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HomeMy WebLinkAboutRG23-0005+-+Hydrology+Report+-+Approved For Property Located in a Portion of The East half of Section 32, Township 4 South, Range 6 East, S.B.M. Palm Desert, California TRACT MAP 38434 EXPLORE PALM DESERT January 10, 2024 Prepared for: Pulte Home Company, LLC 27401 Los Altos, Suite 400 Mission Viejo, CA 92691 JN: 2636 MASS/ROUGH GRADING HYDROLOGY REPORT APPROVED 01/19/2024 TY Tract No. 38434 / Explore Palm Desert Mass/Rough Grading Hydrology Report TABLE OF CONTENTS PROJECT LOCATION .................................................................................................... 1 EXISTING CONDITIONS ............................................................................................... 1 Flood Rate Map ..................................................................................................................1 Existing Topography and Storm Flows .................................................................................1 PROPOSED FLOOD CONTROL REQUIREMENTS ............................................................ 1 HYDROLOGY ANALYSIS DESIGN CRITERIA .................................................................... 1 Hydrologic Soil Group .........................................................................................................2 Antecedent Moisture Condition ...........................................................................................2 Land Use Classifications and Runoff Index Numbers .............................................................2 Precipitation Frequency Estimates .......................................................................................2 Site Infiltration ...................................................................................................................2 SUMMARY of SYNTHETIC UNIT (SHORTCUT METHOD) ANALYSES ................................ 3 PRELIMINARY WQMP ANALYSIS ................................................................................. 3 RESULTS AND CONCLUSIONS ...................................................................................... 3 LIST OF APPENDICES A. RIVERSIDE COUNTY TLMA VICINITY MAP B. NFIP FLOOD INSURANCE RATE MAP C. USDA NCSS HYDROLOGIC SOILS MAP D. NOAA ATLAS 14 & RCFCD REFERENCE PLATES E. PERCOLATION TEST SUMMARY F. PROPOSED LAND USE-SYNTHETIC SUMMARY, PROPOSED LAND USE-WQMP SUMMARY AND ONSITE RETENTION BASIN SUMMARY G. RCFCD SYNTHETIC UNIT HYDROGRAPH WORKSHEETS H. RIVERSIDE COUNTY WHITEWATER RIVER REGION WQMP WORKSHEETS I. MASS/ROUGH GRADING SYNTHETIC UNIT HYDROGRAPH (SHORTCUT METHOD) EXHIBIT Tract No. 38434 / Explore Palm Desert Mass/Rough Grading Hydrology Report 1 PROJECT LOCATION The proposed project site comprises approximately 93 acres located at the southeast corner of Gerald Ford Drive and Rembrandt Parkway, in the City of Palm Desert, Riverside County. The site is described as being a portion of the East ½ of Section 32, Township 4 South, Range 6 East, San Bernardino Base and Meridian and is assigned as a portion of Assessor’s Parcel Number 694-310- 002, 003 & 006. A vicinity map obtained from the Riverside TLMA website is included as Appendix A. EXISTING CONDITIONS Flood Rate Map The proposed (to be developed) area is covered by FIRM Panel Number 06065C1595G, revised August 28, 2008, which indicates the project area lies within Zone X. Zone X is defined as “Areas determined to be outside the 0.2% annual chance floodplain. The Flood Rate Map and definitions of FEMA Flodd Zone Designations are included in Appendix B. Existing Topography and Storm Flows The subject area is a sand dune that is sightly vegetated with typical desert vegetation (scrub brush and low-lying plants) throughout the site. Topographically, the site slopes to the east. Surface drainage on this undeveloped property is relatively flat with no defined drainage pattern, or evidence of storm flows leaving this site. PROPOSED FLOOD CONTROL REQUIREMENTS Drainage requirements fall under the authority of the City of Palm Desert. The project design shall provide for the capture and storage of storm flow from the 100-year storm event for the project area. Future proposed catch basins (by separate Storm Drain Plan) will intercept and convey storm flows through storm drain piping to retention basins as shown on the Synthetic Unit Hydrograph (Shortcut Method) Exhibit in Appendix I. All of the proposed retention basins exceed the 100 year storm volumes, any Force Majeure flows will overflow from the proposed retention basin(s) to the public street(s) and eventually Gerald Ford Dr. As the final design documents (Street Improvement Plan, Storm Drain Plan and Precise Grading Plans are generated, a Final Hydrology and Hydraulics Report will be prepared for the City to review; which will include hydraulic calculations for the associated catch basins and storm drain conveyance system. (Refer to the Synthetic Unit Hydrograph (Shortcut Method) Exhibit included in Appendix I) HYDROLOGY ANALYSIS DESIGN CRITERIA Storm run-off volumes for the 100-year event were obtained utilizing the Synthetic Unit (Shortcut Method) Hydrograph, as described in the RCFC&WCD Hydrology Manual. The shortcut method is appropriate for evaluating areas less than 200 acres in size. The hydrologic data used for the calculations are as follows: Tract No. 38434 / Explore Palm Desert Mass/Rough Grading Hydrology Report 2 Hydrologic Soil Group Soil Group A is defined by RCFCD as – “those soils having high infiltration rates. These soils consist mainly of deep, well drained to excessively drained sands or bravely sands. These soils have a high rate of water transmission.” See Appendix C. Antecedent Moisture Condition AMC II – Moderate runoff potential, an intermediate condition. Per RCFC & WCD Hydrology Manual (Dated: April, 1978): “For the purposes of design hydrology using District methods, AMC II should normally be assumed for both the 10 year and 100 year frequency storm”. Land Use Classifications and Runoff Index Numbers Runoff Index Numbers were obtained from RCFCD Plate E-6.1 and are summarized below: Existing Conditions – Open Brush – Poor 62 Proposed Conditions – Commercial Landscaping 32 Percent of Impervious Cover (RCFCD Plate E-6.3): % Impervious Paving/Hardscape 100% Single Family - Detached 50% Single Family - Attached 65% Recreation Center 60% Landscaping 10% Low Loss Rates: 85% Precipitation Frequency Estimates Precipitation depths were obtained from NOAA Atlas 14: 2 Year - 1 Hour Precipitation: 0.359 inches 100 Year – 1 Hour Precipitation: 1.57 inches 100 Year – 3 Hour Precipitation: 2.27 inches 100 Year - 6 Hour Precipitation 2.98 inches 100 Year – 24 Hour Precipitation 4.59 inches Slope of Intensity Duration Curve: 0.48 See Appendix D for the NOAA Atlas 14 Point Precipitation Frequency Estimates and respective RCFCD Plates. Site Infiltration Percolation tests have been performed on the subject property, reporting percolation rates ranging from 57.0 to 65.5 inches per hour, (Porchet Method). See Onsite Percolation Testing Report prepared by Leighton and Associates, Inc. in Appendix E. For the purposes of this report and utilizing a safety factor greater than ten (10), a percolation rate of five inches (5”) per hour were used in the calculations. Tract No. 38434 / Explore Palm Desert Mass/Rough Grading Hydrology Report 3 SUMMARY of SYNTHETIC UNIT (SHORTCUT METHOD) ANALYSES The subject project area of approximately 93 acres is less than the 200-acre limit guideline for utilization of the shortcut method. The project area is divided into eleven (11) tributary areas. The onsite flows are conveyed via surface drainage to proposed retention basins. Minor off-site flows from the east (Julie Lane) will be conveyed to the retention basin at the north end of the project (Retention basin “G”.) The retention basins are sized to provide storage of the 100-year controlling storm event. (Refer to Retention Basin Summary in Appendix G). All retention basins will have a minimum of one foot (1’) of freeboard. It should be noted that the peak flow for the 1-hour storm is not necessarily representative of peak flow. Per RCFCD, peak discharges from the 3-hour storm should normally compare well with rational method peaks. For the purposes of this report, all hydrologic land use areas were derived from the Proposed Improvement Base. The Proposed Land Use Worksheet Summary is included in Appendix F. Synthetic Unit Hydrograph Worksheets are included in Appendix G. PRELIMINARY WQMP ANALYSIS Preliminary design volume and flow for BMP measures were based on Worksheets 1 and 2 from the Riverside County - Whitewater River Region Water Quality Management Plan (Appendix H). Impervious areas for the tributary drainage areas are derived from the Proposed Land Use Worksheet. A summary of the design flow and volumes are included in the Mass/Rough Grading Synthetic Unit Hydrograph Exhibit included in Appendix I. RESULTS AND CONCLUSIONS As indicated on the hydrology maps and supported by the included calculations, the retention basins have adequate capacity to store the entirety of 100-year storm runoff generated for the project area. Flows above the 100-year storm event would be considered “Force Majeure” flows; in this situation flows would overflow the retention basin(s) to the adjoining public street(s) and ultimately to Gerald Ford Drive. These results conclude that the proposed development meets the hydrologic requirements set forth by the City of Palm Desert. Tract No. 38434 / Explore Palm Desert Mass/Rough Grading Hydrology Report Appendix A Riverside County TLMA Vicinity Map *IMPORTANT* Maps and data are to be used for reference purposes only. Map features are approximate, and are not necessarily accurate to surveying or engineering standards. The County of Riverside makes no warranty or guarantee as to the content (the source is often third party), accuracy, timeliness, or completeness of any of the data provided, and assumes no legal responsibility for the information contained on this map. Any use of this product with respect to accuracy and precision shall be the sole responsibility of the user. © Riverside County RCIT GIS 3,423 Feet Legend Lewis Operating Corp. Notes 1,7120 REPORT PRINTED ON...10/24/2016 1:42:18 PM Gerald Ford Dr. & Portola Ave. Property Display Parcels City Boundaries Cities roadsanno highways HWY INTERCHANGE INTERSTATE OFFRAMP ONRAMP USHWY counties cities hydrographylines waterbodies Lakes Rivers Fred Waring Drive Co o k St r e e t Po r t o l a Av e n u e Mo n t e r e y Av e n u e SITE Pulte Home Company, LLC Gerald Ford Drive Explore Palm Desert Tract No. 38434 / Explore Palm Desert Mass/Rough Grading Hydrology Report Appendix B NFIP Flood Insurance Rate Map SITE DEFINITIONS OF FEMA FLOOD ZONE DESIGNATIONS Moderate to Low Risk Areas In communities that participate in the NFIP, flood insurance is available to all property owners and renters in these zones: ZONE DESCRIPTION X (Shaded) Areas of 0.2% annual chance flood; areas of 1% annual chance flood with average depths of less than 1 foot or with drainage areas less than 1 square mile; and areas protected by levees from 1% annual chance flood. Insurance purchase is not required in these zones. X Areas determined to be outside the 0.2% annual chance floodplain. High Risk Areas In communities that participate in the NFIP, mandatory flood insurance purchase requirements apply to all of these zones: ZONE DESCRIPTION A Areas with a 1% annual chance of flooding and a 26% chance of flooding over the life of a 30-year mortgage. Because detailed analyses are not performed for such areas; no depths or base flood elevations are shown within these zones. AE Areas with a 1% annual chance of flooding and a 26% chance of flooding over the life of a 30-year mortgage. In most instances, base flood elevations derived from detailed analyses are shown at selected intervals within these zones. AH Areas with a 1% annual chance of shallow flooding, usually in the form of a pond, with an average depth ranging from 1 to 3 feet. These areas have a 26% chance of flooding over the life of a 30-year mortgage. Base flood elevations derived from detailed analyses are shown at selected intervals within these zones. AO River or stream flood hazard areas, and areas with a 1% or greater chance of shallow flooding each year, usually in the form of sheet flow, with an average depth ranging from 1 to 3 feet. These areas have a 26% chance of flooding over the life of a 30-year mortgage. Average flood depths derived from detailed analyses are shown within these zones. For areas of alluvial fan flooding, velocities are also determined. AR Areas with a temporarily increased flood risk due to the building or restoration of a flood control system (such as a levee or a dam). Mandatory flood insurance purchase requirements will apply, but rates will not exceed the rates for unnumbered A zones if the structure is built or restored in compliance with Zone AR floodplain management regulations. A99 Areas with a 1% annual chance of flooding that will be protected by a Federal flood control system where construction has reached specified legal requirements. No depths or base flood elevations are shown within these zones. High Risk – Coastal Areas In communities that participate in the NFIP, mandatory flood insurance purchase requirements apply to all of these zones: ZONE DESCRIPTION V Coastal areas with a 1% or greater chance of flooding and an additional hazard associated with storm waves. These areas have a 26% chance of flooding over the life of a 30-year mortgage. No base flood elevations are shown within these zones. VE Coastal areas with a 1% or greater chance of flooding and an additional hazard associated with storm waves. These areas have a 26% chance of flooding over the life of a 30-year mortgage. Base flood elevations derived from detailed analyses are shown at selected intervals within these zones. Undetermined Risk Areas ZONE DESCRIPTION D Areas with possible but undetermined flood hazards. No flood hazard analysis has been conducted. Flood insurance rates are commensurate with the uncertainty of the flood risk. Tract No. 38434 / Explore Palm Desert Mass/Rough Grading Hydrology Report Appendix C USDA NCSS Hydrologic Soils Map Hydrologic Soil Group—Riverside County, Coachella Valley Area, California (Lewis Operating Corp. - Gerald Ford Dr. & Portola Ave.) Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 10/24/2016 Page 1 of 4 37 3 7 3 0 0 37 3 7 5 0 0 37 3 7 7 0 0 37 3 7 9 0 0 37 3 8 1 0 0 37 3 8 3 0 0 37 3 8 5 0 0 37 3 8 7 0 0 37 3 8 9 0 0 37 3 7 3 0 0 37 3 7 5 0 0 37 3 7 7 0 0 37 3 7 9 0 0 37 3 8 1 0 0 37 3 8 3 0 0 37 3 8 5 0 0 37 3 8 7 0 0 37 3 8 9 0 0 557300 557500 557700 557900 558100 558300 558500 557300 557500 557700 557900 558100 558300 558500 33° 47' 22'' N 11 6 ° 2 2 ' 5 6 ' ' W 33° 47' 22'' N 11 6 ° 2 2 ' 4 ' ' W 33° 46' 25'' N 11 6 ° 2 2 ' 5 6 ' ' W 33° 46' 25'' N 11 6 ° 2 2 ' 4 ' ' W N Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 11N WGS84 0 400 800 1600 2400 Feet 0 100 200 400 600 Meters Map Scale: 1:8,620 if printed on A portrait (8.5" x 11") sheet. Warning: Soil Map may not be valid at this scale. Site MA P L E G E N D MA P I N F O R M A T I O N Ar e a o f I n t e r e s t ( A O I ) Ar e a o f I n t e r e s t ( A O I ) So i l s So i l R a t i n g P o l y g o n s A A/ D B B/ D C C/ D D No t r a t e d o r n o t a v a i l a b l e So i l R a t i n g L i n e s A A/ D B B/ D C C/ D D No t r a t e d o r n o t a v a i l a b l e So i l R a t i n g P o i n t s A A/ D B B/ D C C/ D D No t r a t e d o r n o t a v a i l a b l e Wa t e r F e a t u r e s St r e a m s a n d C a n a l s Tr a n s p o r t a t i o n Ra i l s In t e r s t a t e H i g h w a y s US R o u t e s Ma j o r R o a d s Lo c a l R o a d s Ba c k g r o u n d Ae r i a l P h o t o g r a p h y Th e s o i l s u r v e y s t h a t c o m p r i s e y o u r A O I w e r e m a p p e d a t 1 : 2 4 , 0 0 0 . Wa r n i n g : S o i l M a p m a y n o t b e v a l i d a t t h i s s c a l e . En l a r g e m e n t o f m a p s b e y o n d t h e s c a l e o f m a p p i n g c a n c a u s e mi s u n d e r s t a n d i n g o f t h e d e t a i l o f m a p p i n g a n d a c c u r a c y o f s o i l l i n e pl a c e m e n t . T h e m a p s d o n o t s h o w t h e s m a l l a r e a s o f c o n t r a s t i n g so i l s t h a t c o u l d h a v e b e e n s h o w n a t a m o r e d e t a i l e d s c a l e . Pl e a s e r e l y o n t h e b a r s c a l e o n e a c h m a p s h e e t f o r m a p me a s u r e m e n t s . So u r c e o f M a p : N a t u r a l R e s o u r c e s C o n s e r v a t i o n S e r v i c e We b S o i l S u r v e y U R L : h t t p : / / w e b s o i l s u r v e y . n r c s . u s d a . g o v Co o r d i n a t e S y s t e m : W e b M e r c a t o r ( E P S G : 3 8 5 7 ) Ma p s f r o m t h e W e b S o i l S u r v e y a r e b a s e d o n t h e W e b M e r c a t o r pr o j e c t i o n , w h i c h p r e s e r v e s d i r e c t i o n a n d s h a p e b u t d i s t o r t s di s t a n c e a n d a r e a . A p r o j e c t i o n t h a t p r e s e r v e s a r e a , s u c h a s t h e Al b e r s e q u a l - a r e a c o n i c p r o j e c t i o n , s h o u l d b e u s e d i f m o r e a c c u r a t e ca l c u l a t i o n s o f d i s t a n c e o r a r e a a r e r e q u i r e d . Th i s p r o d u c t i s g e n e r a t e d f r o m t h e U S D A - N R C S c e r t i f i e d d a t a a s o f th e v e r s i o n d a t e ( s ) l i s t e d b e l o w . So i l S u r v e y A r e a : R i v e r s i d e C o u n t y , C o a c h e l l a V a l l e y A r e a , Ca l i f o r n i a Su r v e y A r e a D a t a : V e r s i o n 7 , S e p 9 , 2 0 1 4 So i l m a p u n i t s a r e l a b e l e d ( a s s p a c e a l l o w s ) f o r m a p s c a l e s 1 : 5 0 , 0 0 0 or l a r g e r . Da t e ( s ) a e r i a l i m a g e s w e r e p h o t o g r a p h e d : J a n 2 2 , 2 0 1 5 — F e b 1 0 , 20 1 5 Th e o r t h o p h o t o o r o t h e r b a s e m a p o n w h i c h t h e s o i l l i n e s w e r e co m p i l e d a n d d i g i t i z e d p r o b a b l y d i f f e r s f r o m t h e b a c k g r o u n d im a g e r y d i s p l a y e d o n t h e s e m a p s . A s a r e s u l t , s o m e m i n o r s h i f t i n g of m a p u n i t b o u n d a r i e s m a y b e e v i d e n t . Hy d r o l o g i c S o i l G r o u p — R i v e r s i d e C o u n t y , C o a c h e l l a V a l l e y A r e a , C a l i f o r n i a (L e w i s O p e r a t i n g C o r p . - G e r a l d F o r d D r . & P o r t o l a A v e . ) Na t u r a l R e s o u r c e s Co n s e r v a t i o n S e r v i c e We b S o i l S u r v e y Na t i o n a l C o o p e r a t i v e S o i l S u r v e y 10 / 2 4 / 2 0 1 6 Pa g e 2 o f 4 Hydrologic Soil Group Hydrologic Soil Group— Summary by Map Unit — Riverside County, Coachella Valley Area, California (CA680) Map unit symbol Map unit name Rating Acres in AOI Percent of AOI MaB Myoma fine sand, 0 to 5 percent slopes A 21.7 5.4% MaD Myoma fine sand, 5 to 15 percent slopes A 382.1 94.6% Totals for Area of Interest 403.8 100.0% Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. Rating Options Aggregation Method: Dominant Condition Hydrologic Soil Group—Riverside County, Coachella Valley Area, California Lewis Operating Corp. - Gerald Ford Dr. & Portola Ave. Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 10/24/2016 Page 3 of 4 Tract No. 38434 / Explore Palm Desert Mass/Rough Grading Hydrology Report Appendix D NOAA Atlas 14 RCFCD Reference Plates NOAA Atlas 14, Volume 6, Version 2 Location name: Palm Desert, California, USA* Latitude: 33.7815°, Longitude: -116.3772° Elevation: 306.99 ft** * source: ESRI Maps ** source: USGS POINT PRECIPITATION FREQUENCY ESTIMATES Sanja Perica, Sarah Dietz, Sarah Heim, Lillian Hiner, Kazungu Maitaria, Deborah Martin, Sandra Pavlovic, Ishani Roy, Carl Trypaluk, Dale Unruh, Fenglin Yan, Michael Yekta, Tan Zhao, Geoffrey Bonnin, Daniel Brewer, Li-Chuan Chen, Tye Parzybok, John Yarchoan NOAA, National Weather Service, Silver Spring, Maryland PF_tabular | PF_graphical | Maps_&_aerials PF tabular PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches)1 Duration Average recurrence interval (years) 1 2 5 10 25 50 100 200 500 1000 5-min 0.060 (0.050‑0.073) 0.092 (0.077‑0.112) 0.142 (0.118‑0.173) 0.188 (0.155‑0.231) 0.262 (0.208‑0.332) 0.327 (0.255‑0.424) 0.403 (0.306‑0.537) 0.493 (0.364‑0.675) 0.637 (0.450‑0.909) 0.772 (0.527‑1.14) 10-min 0.086 (0.072‑0.104) 0.132 (0.110‑0.161) 0.203 (0.169‑0.248) 0.270 (0.222‑0.331) 0.375 (0.298‑0.476) 0.469 (0.365‑0.608) 0.578 (0.439‑0.769) 0.707 (0.522‑0.967) 0.912 (0.646‑1.30) 1.11 (0.756‑1.64) 15-min 0.104 (0.087‑0.126) 0.160 (0.133‑0.194) 0.246 (0.204‑0.299) 0.326 (0.269‑0.400) 0.453 (0.361‑0.576) 0.567 (0.442‑0.736) 0.699 (0.531‑0.930) 0.855 (0.631‑1.17) 1.10 (0.781‑1.58) 1.34 (0.914‑1.98) 30-min 0.160 (0.134‑0.194) 0.247 (0.206‑0.300) 0.379 (0.315‑0.461) 0.503 (0.414‑0.617) 0.699 (0.556‑0.887) 0.874 (0.681‑1.13) 1.08 (0.819‑1.43) 1.32 (0.972‑1.80) 1.70 (1.20‑2.43) 2.06 (1.41‑3.05) 60-min 0.233 (0.194‑0.283) 0.359 (0.299‑0.436) 0.552 (0.458‑0.671) 0.731 (0.602‑0.897) 1.02 (0.809‑1.29) 1.27 (0.990‑1.65) 1.57 (1.19‑2.08) 1.92 (1.41‑2.62) 2.47 (1.75‑3.53) 3.00 (2.05‑4.43) 2-hr 0.332 (0.276‑0.402) 0.498 (0.414‑0.604) 0.746 (0.619‑0.907) 0.972 (0.800‑1.19) 1.32 (1.05‑1.68) 1.63 (1.27‑2.11) 1.97 (1.50‑2.62) 2.37 (1.75‑3.24) 2.97 (2.10‑4.24) 3.52 (2.40‑5.20) 3-hr 0.399 (0.332‑0.483) 0.594 (0.494‑0.721) 0.882 (0.732‑1.07) 1.14 (0.941‑1.40) 1.54 (1.23‑1.96) 1.89 (1.47‑2.45) 2.27 (1.73‑3.02) 2.71 (2.00‑3.71) 3.37 (2.39‑4.81) 3.96 (2.70‑5.85) 6-hr 0.540 (0.450‑0.654) 0.802 (0.667‑0.973) 1.18 (0.983‑1.44) 1.53 (1.26‑1.87) 2.04 (1.63‑2.60) 2.49 (1.94‑3.23) 2.98 (2.26‑3.96) 3.53 (2.61‑4.83) 4.36 (3.08‑6.22) 5.07 (3.46‑7.50) 12-hr 0.643 (0.536‑0.779) 0.972 (0.809‑1.18) 1.45 (1.21‑1.77) 1.88 (1.55‑2.31) 2.53 (2.01‑3.21) 3.09 (2.40‑4.00) 3.70 (2.81‑4.92) 4.39 (3.24‑6.01) 5.43 (3.84‑7.75) 6.33 (4.32‑9.35) 24-hr 0.754 (0.667‑0.869) 1.17 (1.03‑1.35) 1.77 (1.56‑2.05) 2.31 (2.02‑2.69) 3.12 (2.64‑3.76) 3.82 (3.17‑4.69) 4.59 (3.72‑5.77) 5.45 (4.31‑7.05) 6.76 (5.13‑9.10) 7.89 (5.79‑11.0) 2-day 0.833 (0.738‑0.961) 1.31 (1.16‑1.51) 2.00 (1.76‑2.31) 2.61 (2.28‑3.04) 3.52 (2.98‑4.24) 4.29 (3.57‑5.28) 5.15 (4.17‑6.47) 6.10 (4.81‑7.88) 7.52 (5.70‑10.1) 8.73 (6.40‑12.1) 3-day 0.874 (0.774‑1.01) 1.38 (1.22‑1.59) 2.12 (1.87‑2.45) 2.76 (2.42‑3.22) 3.73 (3.16‑4.49) 4.54 (3.77‑5.58) 5.44 (4.41‑6.84) 6.43 (5.08‑8.31) 7.91 (6.00‑10.6) 9.17 (6.73‑12.8) 4-day 0.904 (0.801‑1.04) 1.43 (1.27‑1.66) 2.20 (1.94‑2.55) 2.88 (2.52‑3.36) 3.88 (3.29‑4.68) 4.73 (3.93‑5.81) 5.66 (4.59‑7.12) 6.69 (5.28‑8.64) 8.22 (6.23‑11.1) 9.51 (6.98‑13.2) 7-day 0.955 (0.845‑1.10) 1.53 (1.35‑1.77) 2.36 (2.08‑2.73) 3.10 (2.71‑3.61) 4.18 (3.54‑5.04) 5.09 (4.23‑6.26) 6.08 (4.93‑7.65) 7.18 (5.67‑9.28) 8.80 (6.67‑11.8) 10.2 (7.46‑14.1) 10-day 0.995 (0.881‑1.15) 1.60 (1.42‑1.85) 2.49 (2.19‑2.88) 3.26 (2.86‑3.81) 4.42 (3.74‑5.32) 5.38 (4.47‑6.61) 6.43 (5.22‑8.09) 7.59 (5.99‑9.81) 9.30 (7.05‑12.5) 10.7 (7.88‑14.9) 20-day 1.06 (0.939‑1.22) 1.73 (1.53‑2.00) 2.72 (2.40‑3.14) 3.59 (3.14‑4.18) 4.89 (4.14‑5.88) 5.97 (4.96‑7.34) 7.16 (5.80‑9.01) 8.46 (6.68‑10.9) 10.4 (7.86‑14.0) 12.0 (8.77‑16.6) 30-day 1.16 (1.03‑1.34) 1.91 (1.69‑2.21) 3.02 (2.66‑3.49) 4.00 (3.50‑4.67) 5.48 (4.64‑6.60) 6.72 (5.58‑8.26) 8.07 (6.54‑10.2) 9.55 (7.54‑12.3) 11.7 (8.89‑15.8) 13.5 (9.92‑18.8) 45-day 1.24 (1.10‑1.43) 2.07 (1.83‑2.38) 3.29 (2.90‑3.80) 4.39 (3.84‑5.12) 6.05 (5.13‑7.29) 7.46 (6.20‑9.17) 8.99 (7.29‑11.3) 10.7 (8.43‑13.8) 13.1 (9.95‑17.7) 15.2 (11.1‑21.1) 60-day 1.34 (1.18‑1.54) 2.23 (1.97‑2.57) 3.57 (3.14‑4.13) 4.78 (4.18‑5.58) 6.62 (5.61‑7.98) 8.19 (6.80‑10.1) 9.91 (8.03‑12.5) 11.8 (9.30‑15.2) 14.5 (11.0‑19.5) 16.8 (12.3‑23.3) 1 Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS). Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequency estimates (for a given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper bounds are not checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values. Please refer to NOAA Atlas 14 document for more information. Back to Top PF graphical PROJECT NAME PROJECT NUMBER 2636 STORM EVENT 100 yr DATE: MINUTES RAINFALL RAINFALL INTENSITY DEPTH (in/hr)(in) 5 4.84 0.40 10 3.47 0.58 15 2.80 0.70 30 2.16 1.08 60 1.57 1.57 120 0.99 1.97 CONSTANT FROM GRAPH 10.64 EXPONENT FROM GRAPH -0.48 MINUTES RAINFALL RAINFALL INTENSITY DEPTH (in/hr)(in) 5 4.91 0.41 10 3.52 0.59 15 2.90 0.73 20 2.53 0.84 25 2.27 0.95 30 2.08 1.04 35 1.93 1.13 40 1.81 1.21 45 1.71 1.28 50 1.63 1.36 55 1.55 1.42 60 1.49 1.49 65 1.43 1.55 70 1.38 1.62 75 1.34 1.67 80 1.30 1.73 85 1.26 1.79 90 1.23 1.84 95 1.20 1.89 100 1.17 1.94 105 1.14 1.99 110 1.11 2.04 115 1.09 2.09 120 1.07 2.14 INTENSITY VALUES FROM GRAPH NOAA ATLAS 14 INTENSITY - DURATION WORKSHEET Del Webb Explore at Palm Desert DATA FROM NOAA ATLAS 14 January 9, 2024 y = 10.64x-0.48 0.10 1.00 10.00 1 10 100 1000 0. 4 5 0. 7 4 Tract No. 38434 / Explore Palm Desert Mass/Rough Grading Hydrology Report Appendix E Percolation Test Results Onsite Percolation Test Results prepared by Leighton and Associates, Inc Dated: September 28, 2023 September 28, 2023 Project No. 13629.003 Pulte Home Company 27401 Los Altos, Ste 400 Mission Viejo, CA 92691 Attention: Mr. David Dewegeli Subject: Results of Onsite Percolation Testing Proposed Residential Development – Del Webb Explore APN’s Tentative Tract Map 38434 of -006 City of Palm Desert, California In accordance with your request and authorization, Leighton and Associates, Inc. (Leighton) is pleased to present this percolation test report for the water quality basin associated with the subject development, located southwest of Gerald Ford Drive and Portola Road, in the City of Palm Desert, California (See Figure 1). PURPO SE AN D SCO PE OF WORK The purpose of our testing was to determine general infiltration rates of onsite soils with respect to the proposed retention basins to be located near Lot C, Lot L, and Lot O, within the proposed Explore development (See Figure 2). Services provided for this study consisted of the following: Four (4) percolation tests in accordance with the procedures outlined in the referenced Handbook, at pre-determined locations identified by MSA Consulting, Inc. Compilation of this report that presents the results of our percolation/infiltration testing. SI TE D ESCR I PTION The overall project site is located on previous undeveloped land, situated southwest of Gerald Ford Drive and Portola Avenue, in the City of Palm Desert, California (see Figure 1, Site Location Map). Topographically, the site and surrounding area slopes to the east and northeast. Site elevations range from high point elevation of approximately 323 feet above mean sea level (msl) near the southwestern corner to a low point elevation of approximately 270 (msl) near the northeast corner of the property. The site is currently vacant sand dune topography. Results of Onsite Percolation Testing Project No. 13629.003 Del Webb Explore, Palm Desert, California September 28, 2023 2 Based on the provided site plan by MSA Consulting, Inc., we understand that three retention basins are planned throughout the site. One retention basin is included within Lot C, with an approximate bottom elevation of 272.3 feet msl, one with Lot L with an approximate bottom elevation of 294.0 feet msl, and one with Lot O with an approximate bottom elevation of 291.0 feet msl. The planned basin bottoms are approximately 6 to 10 feet below existing ground elevations. SUBSU RFACE INVESTIGA TI ON Our field investigation consisted of excavating four percolation test holes at each of the pre-determined locations within the proposed basins (at approximately 6 to 10 feet bgs) on September 18, 2023. During a previous study (Leighton, 2022), we have also excavated, logged, and sampled seven exploratory hollow-stem auger borings to a maximum depth of approximately 51.5 feet below ground surface (bgs) to collect samples and verify depth to groundwater and/or impermeable strata. The locations of the percolation test holes are shown on Figure 2. SOI LS AND GROUNDWATER CONDITION S Based on the results of this study, the site is underlain by Quaternary Younger Alluvium consisting primarily of light brown to brownish gray, medium dense to very dense, poorly graded fine sand with silt (SP-SM). During a previous study (Leighton, 2022), groundwater was not encountered in any of our borings to the maximum explored depth of 51.5 feet below ground surface (bgs), and no standing water was observed on the ground surface during the time of the investigation. PERCOLATION TEST RE SU LTS After presoaking the percolation test holes on September 18, 2023, we returned to site after 24 hours to perform the infiltration testing. Percolation testing was performed in general accordance with the procedures of Appendix A, Section 2.3 of the Riverside County Design Handbook referenced above. Results reported below are the most conservative reading in minutes per inch drop and converted to inches per hour per the Porchet method. No factor of safety (FS) has been applied to these rates. Field test data are included in Appendix A. Results of Onsite Percolation Testing Project No. 13629.003 Del Webb Explore, Palm Desert, California September 28, 2023 3 Summary of Percolation/Infiltration Test Results Test Hole # Ex. Ground Surface Elev. (ft) Depth BGS (ft) Percolation Rate (min/in) Infiltration Rate (in/hr) Soil Description/Notes LP-1 279 8 0.05 57.0 SAND with Silt (SP-SM) LP-2 279 8 0.05 60.8 SAND with Silt (SP-SM) LP-3 302 10 0.04 65.5 SAND with Silt (SP-SM) LP-4 299 6 0.10 57.6 SAND with Silt (SP-SM) CONCLUSION S As summarized above, the onsite infiltration rates are relatively high due to poorly graded and relatively clean sand. The results of our exploratory Borings (Leighton, 2022, and Appendix A) indicate that a minimum of 5 feet of permeable soils exist below basins bottom and groundwater is not expected to encroach to within 10 feet below bottom of basins. LIMI TA TION S The above findings and recommendations are based on a general interpretation of soils conditions between test locations, utilizing contemporary engineering principles and practice. We make no other warranty, either expressed or implied. Please notify the engineer in the event conditions are encountered that are not reflected in this report. If you have any questions, please do not hesitate to contact this office. We appreciate this opportunity to be of service. Respectfully submitted, LEIGHTON AND ASSOCIATES, INC. Senior Project Engineer Attachments: Figure 1 – Site Location Map Figure 2 – Boring Location Map Appendix A – Logs of Exploratory Borings and Percolation Test Results Appendix B – Laboratory Test Results Distribution: (1) addressee (PDF copy via email) Results of Onsite Percolation Testing Project No. 13629.003 Del Webb Explore, Palm Desert, California September 28, 2023 Reference Leighton & Associates, Inc., 2022, Preliminary Geotechnical Exploration – Due Diligence, Refuge Palm Desert, Approximately 79 Acre Del Webb Property, Palm Desert, California, PN 13629.001, Dated August 10. Riverside County Flood Control District, Design Handbook for Low Impact Development Best Management Practices, dated September 2018. MSA, 2023, Refuge, Palm Desert, TTM 38434, Preliminary Grading and Drainage Exhibit, dated August 17, 2023. Scale: Base Map: Bing Maps 2023 1 " = 2,000 ' Project: 13629.003 Eng/Geol: BSS/R FR Map Saved as V:\Drafting\13629\003\Maps\13629-003_F01_SLM_2023-09-26.mxd on 9/26/2023 11:17:08 AM Author: (btran) Date: September 2023 Ap proximateSite Boun dary FIGURE 1SITE LOCATION MAPPulte – ExploreTTM 38434Palm Desert, California ³ 0 2,000 4,000 Feet &(&( &( &( LP-1 LP-2 LP-3 LP-4 LEGEND &(Approxim a te b oring loc a tion Approxim a te S ite Bounda ry ³ 0 300 600 Feet Ma p S a v ed a s V:\Dra fting \13629\003\Ma ps\13629-003_F02_BLM_2023-09-26.m xd on 9/26/2023 11:15:10 AM BORING LOCATION MAPP ulte – ExploreTTM 38434P a lm Desert, Ca lifornia S ca le: Ba se Ma p: P relim ina ry Gra ding a nd Dra ina g e Exh ib itda ted: Aug ust 17, 2023 b y MS A Consulting , Inc. 1 " = 300 ' P rojec t: 13629.003 Eng /Geol: BS S /RFR Auth or: (b tra n) Da te: S eptem b er 2023 FIGURE 2 LP-4 LB-1 &( APPENDIX A LOG OF EXPLORATORY BORINGS AND PERCOLATION TEST RESULTS 105 102 SP SP-SM B1 R1 R2 R3 R4 R5 0 0 Poorly graded SAND, loose, gray to yellow, dry, medium to coarse sand, MD = 113.0 @ 13.0, RV = 69, FINES 4% No recovery No recovery Poorly graded SAND, medium dense, gray, dry, medium to coarse sand Poorly graded SAND with Silt, medium dense, grayish brown, moist, some fines, some mica -200 = 6 No Recovery MD, RV, SA -200 5 8 12 11 20 23 10 16 25 15 28 44 17 28 55 SIEVE ANALYSIS SAND EQUIVALENT SPECIFIC GRAVITY UNCONFINED COMPRESSIVE STRENGTH GEOTECHNICAL BORING LOG LB-1 Hole Diameter Mo i s t u r e Ground Elevation De p t h Bl o w s El e v a t i o n Pe r 6 I n c h e s Page 1 of 2 ~297' BULK SAMPLE CORE SAMPLE GRAB SAMPLE RING SAMPLE SPLIT SPOON SAMPLE TUBE SAMPLE B C G R S T MJM Hollow Stem Auger - 140lb - Autohammer - 30" Drop So i l C l a s s . 7-20-22 SOIL DESCRIPTION Sampled By Drilling Co.Drilling Co. Project Project No. See Boring Location Map Pulte Del Webb Refuge 13629.001 Drilling Method 8" Sa m p l e N o . Fe e t At t i t u d e s SAMPLE TYPES: 2R Drilling * * * This log is a part of a report by Leighton and should not be used as a stand-alone document. * * * Co n t e n t , % Logged By Date Drilled MJM Fe e t S (U . S . C . S . ) Lo g Ty p e o f T e s t s Gr a p h i c pc f Location Dr y D e n s i t y N This Soil Description applies only to a location of the exploration at the time of sampling. Subsurface conditions may differ at other locations and may change with time. The description is a simplification of the actual conditions encountered. Transitions between soil types may be gradual. TYPE OF TESTS: -200 AL CN CO CR CU % FINES PASSING ATTERBERG LIMITS CONSOLIDATION COLLAPSE CORROSION UNDRAINED TRIAXIAL DS EI H MD PP RV DIRECT SHEAR EXPANSION INDEX HYDROMETER MAXIMUM DENSITY POCKET PENETROMETER R VALUE SA SE SG UC 0 5 10 15 20 25 30 SP-SMS6 S7 S8 S9 S10 0.3 0.4 SAND, dense, gray, dry, some fines -200 = 5 No Recovery dense, gray, dry, fine sand, some fines, some mica No recovery Poorly graded SAND with Silt, very dense, grayish brown, dry, fine sand, some mica Total Depth 51.5' No Groundwater Encountered Backfilled 7/20/22 -20015 20 28 14 24 33 15 25 33 17 18 21 22 32 37 SIEVE ANALYSIS SAND EQUIVALENT SPECIFIC GRAVITY UNCONFINED COMPRESSIVE STRENGTH GEOTECHNICAL BORING LOG LB-1 Hole Diameter Mo i s t u r e Ground Elevation De p t h Bl o w s El e v a t i o n Pe r 6 I n c h e s Page 2 of 2 ~297' BULK SAMPLE CORE SAMPLE GRAB SAMPLE RING SAMPLE SPLIT SPOON SAMPLE TUBE SAMPLE B C G R S T MJM Hollow Stem Auger - 140lb - Autohammer - 30" Drop So i l C l a s s . 7-20-22 SOIL DESCRIPTION Sampled By Drilling Co.Drilling Co. Project Project No. See Boring Location Map Pulte Del Webb Refuge 13629.001 Drilling Method 8" Sa m p l e N o . Fe e t At t i t u d e s SAMPLE TYPES: 2R Drilling * * * This log is a part of a report by Leighton and should not be used as a stand-alone document. * * * Co n t e n t , % Logged By Date Drilled MJM Fe e t S (U . S . C . S . ) Lo g Ty p e o f T e s t s Gr a p h i c pc f Location Dr y D e n s i t y N This Soil Description applies only to a location of the exploration at the time of sampling. Subsurface conditions may differ at other locations and may change with time. The description is a simplification of the actual conditions encountered. Transitions between soil types may be gradual. TYPE OF TESTS: -200 AL CN CO CR CU % FINES PASSING ATTERBERG LIMITS CONSOLIDATION COLLAPSE CORROSION UNDRAINED TRIAXIAL DS EI H MD PP RV DIRECT SHEAR EXPANSION INDEX HYDROMETER MAXIMUM DENSITY POCKET PENETROMETER R VALUE SA SE SG UC 30 35 40 45 50 55 60 SP-SMB1 Poorly graded SAND, loose, gray to yellow, dry, medium to coarse sand, (SA: 6% FINES) Total Depth 8' No Groundwater Encountered Backfilled 9/18/2023 SA SIEVE ANALYSIS SAND EQUIVALENT SPECIFIC GRAVITY UNCONFINED COMPRESSIVE STRENGTH GEOTECHNICAL BORING LOG LP-1 Hole Diameter Mo i s t u r e Ground Elevation De p t h Bl o w s El e v a t i o n Pe r 6 I n c h e s Page 1 of 1 279' BULK SAMPLE CORE SAMPLE GRAB SAMPLE RING SAMPLE SPLIT SPOON SAMPLE TUBE SAMPLE B C G R S T MJM Hollow Stem Auger - 140lb - Autohammer - 30" Drop So i l C l a s s . 9-18-23 SOIL DESCRIPTION Sampled By Drilling Co.Drilling Co. Project Project No. See Boring Location Map Pulte Del Webb Perc Testing 13629.003 Drilling Method 8" Sa m p l e N o . Fe e t At t i t u d e s SAMPLE TYPES: 2R Drilling * * * This log is a part of a report by Leighton and should not be used as a stand-alone document. * * * Co n t e n t , % Logged By Date Drilled MJM Fe e t S (U . S . C . S . ) Lo g Ty p e o f T e s t s Gr a p h i c pc f Location Dr y D e n s i t y N This Soil Description applies only to a location of the exploration at the time of sampling. Subsurface conditions may differ at other locations and may change with time. The description is a simplification of the actual conditions encountered. Transitions between soil types may be gradual. TYPE OF TESTS: -200 AL CN CO CR CU % FINES PASSING ATTERBERG LIMITS CONSOLIDATION COLLAPSE CORROSION UNDRAINED TRIAXIAL DS EI H MD PP RV DIRECT SHEAR EXPANSION INDEX HYDROMETER MAXIMUM DENSITY POCKET PENETROMETER R VALUE SA SE SG UC 275 270 265 260 0 5 10 15 20 SP-SM Poorly graded SAND Poorly graded SAND, medium dense, gray, dry, coarse sand, some fines Total Depth 8' No Groundwater Encountered Backfilled 9/18/2023 SIEVE ANALYSIS SAND EQUIVALENT SPECIFIC GRAVITY UNCONFINED COMPRESSIVE STRENGTH GEOTECHNICAL BORING LOG LP-2 Hole Diameter Mo i s t u r e Ground Elevation De p t h Bl o w s El e v a t i o n Pe r 6 I n c h e s Page 1 of 1 279' BULK SAMPLE CORE SAMPLE GRAB SAMPLE RING SAMPLE SPLIT SPOON SAMPLE TUBE SAMPLE B C G R S T MJM Hollow Stem Auger - 140lb - Autohammer - 30" Drop So i l C l a s s . 9-18-23 SOIL DESCRIPTION Sampled By Drilling Co.Drilling Co. Project Project No. See Boring Location Map Pulte Del Webb Perc Testing 13629.003 Drilling Method 8" Sa m p l e N o . Fe e t At t i t u d e s SAMPLE TYPES: 2R Drilling * * * This log is a part of a report by Leighton and should not be used as a stand-alone document. * * * Co n t e n t , % Logged By Date Drilled MJM Fe e t S (U . S . C . S . ) Lo g Ty p e o f T e s t s Gr a p h i c pc f Location Dr y D e n s i t y N This Soil Description applies only to a location of the exploration at the time of sampling. Subsurface conditions may differ at other locations and may change with time. The description is a simplification of the actual conditions encountered. Transitions between soil types may be gradual. TYPE OF TESTS: -200 AL CN CO CR CU % FINES PASSING ATTERBERG LIMITS CONSOLIDATION COLLAPSE CORROSION UNDRAINED TRIAXIAL DS EI H MD PP RV DIRECT SHEAR EXPANSION INDEX HYDROMETER MAXIMUM DENSITY POCKET PENETROMETER R VALUE SA SE SG UC 275 270 265 260 0 5 10 15 20 SP-SMB1 Poorly graded SAND with Silt, medium dense, gray, dry, no recovery (SA: 8% FINES) fine to coarse sand Total Depth 10' No Groundwater Encountered Backfilled 9/18/2023 SA SIEVE ANALYSIS SAND EQUIVALENT SPECIFIC GRAVITY UNCONFINED COMPRESSIVE STRENGTH GEOTECHNICAL BORING LOG LP-3 Hole Diameter Mo i s t u r e Ground Elevation De p t h Bl o w s El e v a t i o n Pe r 6 I n c h e s Page 1 of 1 303' BULK SAMPLE CORE SAMPLE GRAB SAMPLE RING SAMPLE SPLIT SPOON SAMPLE TUBE SAMPLE B C G R S T MJM Hollow Stem Auger - 140lb - Autohammer - 30" Drop So i l C l a s s . 9-18-23 SOIL DESCRIPTION Sampled By Drilling Co.Drilling Co. Project Project No. See Boring Location Map Pulte Del Webb Perc Testing 13629.003 Drilling Method 8" Sa m p l e N o . Fe e t At t i t u d e s SAMPLE TYPES: 2R Drilling * * * This log is a part of a report by Leighton and should not be used as a stand-alone document. * * * Co n t e n t , % Logged By Date Drilled MJM Fe e t S (U . S . C . S . ) Lo g Ty p e o f T e s t s Gr a p h i c pc f Location Dr y D e n s i t y N This Soil Description applies only to a location of the exploration at the time of sampling. Subsurface conditions may differ at other locations and may change with time. The description is a simplification of the actual conditions encountered. Transitions between soil types may be gradual. TYPE OF TESTS: -200 AL CN CO CR CU % FINES PASSING ATTERBERG LIMITS CONSOLIDATION COLLAPSE CORROSION UNDRAINED TRIAXIAL DS EI H MD PP RV DIRECT SHEAR EXPANSION INDEX HYDROMETER MAXIMUM DENSITY POCKET PENETROMETER R VALUE SA SE SG UC 300 295 290 285 0 5 10 15 20 SP-SM Poorly graded SAND, loose, gray, dry, fine to coarse sand same as above, some mica Total Depth 6' No Groundwater Encountered Backfilled 9/18/2023 SIEVE ANALYSIS SAND EQUIVALENT SPECIFIC GRAVITY UNCONFINED COMPRESSIVE STRENGTH GEOTECHNICAL BORING LOG LP-4 Hole Diameter Mo i s t u r e Ground Elevation De p t h Bl o w s El e v a t i o n Pe r 6 I n c h e s Page 1 of 1 299' BULK SAMPLE CORE SAMPLE GRAB SAMPLE RING SAMPLE SPLIT SPOON SAMPLE TUBE SAMPLE B C G R S T MJM Hollow Stem Auger - 140lb - Autohammer - 30" Drop So i l C l a s s . 9-18-23 SOIL DESCRIPTION Sampled By Drilling Co.Drilling Co. Project Project No. See Boring Location Map Pulte Del Webb Perc Testing 13629.003 Drilling Method 8" Sa m p l e N o . Fe e t At t i t u d e s SAMPLE TYPES: 2R Drilling * * * This log is a part of a report by Leighton and should not be used as a stand-alone document. * * * Co n t e n t , % Logged By Date Drilled MJM Fe e t S (U . S . C . S . ) Lo g Ty p e o f T e s t s Gr a p h i c pc f Location Dr y D e n s i t y N This Soil Description applies only to a location of the exploration at the time of sampling. Subsurface conditions may differ at other locations and may change with time. The description is a simplification of the actual conditions encountered. Transitions between soil types may be gradual. TYPE OF TESTS: -200 AL CN CO CR CU % FINES PASSING ATTERBERG LIMITS CONSOLIDATION COLLAPSE CORROSION UNDRAINED TRIAXIAL DS EI H MD PP RV DIRECT SHEAR EXPANSION INDEX HYDROMETER MAXIMUM DENSITY POCKET PENETROMETER R VALUE SA SE SG UC 295 290 285 280 0 5 10 15 20 96 8 ° 7:44:00 * Based on Prochet Method Percolation Project Number:13629.003 P-1 Date:Sep-23 Test Data Project Name:Pulte Explorer Perc Basins 4.00 20.00 96.00 76.00 57.000 0.053 4.00 20.00 96.00 76.00 57.000 0.053 4.00 20.00 96.00 76.00 57.000 0.053 3.50 20.00 96.00 76.00 65.143 0.046 3.00 20.00 96.00 76.00 76.000 0.039 3.00 20.00 96.00 76.00 76.000 0.039 3.00 20.00 96.00 76.00 76.000 0.039 inches/hour* minute/inch 3.00 20.00 96.00 76.00 76.000 0.039 USCS Soil Type:Sand with Silt (SP-SM)Diameter (in.)Sunny ~90 Time Δt (min)Initial Water Depth (inches) Final Water Depth (inches) Change In Water Level (inches) Infiltration/Percolation Rate Tested by:MJM Date Tested 9/19/2023 Soil Unit: Alluvial (Qal)Depth of Test Hole (in.) Test Hole Number:P-1 Project Pulte Del Webb Explore Date Excavated:9/18/2023 Project Number 13629.003 0.000 10.000 20.000 30.000 40.000 50.000 60.000 70.000 80.000 0 10 20 30 40 50 60 70 80 90 100 Infiltration Rate (in./hr) Time (min) 96 8 ° 7:35:00 Date:Sep-23 * Based on Prochet Method Percolation Project Number:13629.003 Test Data Project Name:Pulte Explorer Perc BasinsP-2 3.75 20.00 96.00 76.00 60.800 0.049 3.75 20.00 96.00 76.00 60.800 0.049 3.75 20.00 96.00 76.00 60.800 0.049 3.25 20.00 96.00 76.00 70.154 0.043 3.00 20.00 96.00 76.00 76.000 0.039 3.00 20.00 96.00 76.00 76.000 0.039 2.00 20.00 96.00 76.00 114.000 0.026 inches/hour* minute/inch 2.00 20.00 96.00 76.00 114.000 0.026 USCS Soil Type:Sand with Silt (SP-SM)Diameter (in.)Sunny ~90 Time Δt (min)Initial Water Depth (inches) Final Water Depth (inches) Change In Water Level (inches) Infiltration/Percolation Rate Tested by:MJM Date Tested 9/19/2023 Soil Unit: Alluvial (Qal)Depth of Test Hole (in.) Test Hole Number:P-2 Project Pulte Del Webb Explore Date Excavated:9/18/2023 Project Number 13629.003 0.000 20.000 40.000 60.000 80.000 100.000 120.000 0 10 20 30 40 50 60 70 80 90 100 Infiltration Rate (in./hr) Time (min) 120 8 ° 8:00:00 Tested by:MJM Date Tested 9/19/2023 Soil Unit: Alluvial (Qal)Depth of Test Hole (in.) Test Hole Number:P-3 Project Pulte Del Webb Explore Date Excavated:9/18/2023 Project Number 13629.003 inches/hour* minute/inch 2.25 36.00 120.00 84.00 101.818 0.027 USCS Soil Type:Sand with Silt (SP-SM)Diameter (in.)Sunny ~90 Time Δt (min)Initial Water Depth (inches) Final Water Depth (inches) Change In Water Level (inches) Infiltration/Percolation Rate 3.00 36.00 120.00 84.00 76.364 0.036 2.50 36.00 120.00 84.00 91.636 0.030 3.00 36.00 120.00 84.00 76.364 0.036 3.00 36.00 120.00 84.00 76.364 0.036 3.50 36.00 120.00 84.00 65.455 0.042 3.00 36.00 120.00 84.00 76.364 0.036 3.50 36.00 120.00 84.00 65.455 0.042 Date:Sep-23 * Based on Prochet Method Percolation Project Number:13629.003 Test Data Project Name:Pulte Explorer Perc BasinsP-3 0.000 20.000 40.000 60.000 80.000 100.000 120.000 0 10 20 30 40 50 60 70 80 90 100 Infiltration Rate (in./hr) Time (min) 72 8 ° 8:30:00 Tested by:MJM Date Tested 9/19/2023 Soil Unit: Alluvial (Qal)Depth of Test Hole (in.) Test Hole Number:P-4 Project Pulte Del Webb Explore Date Excavated:9/18/2023 Project Number 13629.003 inches/hour* minute/inch 2.00 36.00 72.00 36.00 108.000 0.056 USCS Soil Type:Sand with Silt (SP-SM)Diameter (in.)Sunny ~90 Time Δt (min)Initial Water Depth (inches) Final Water Depth (inches) Change In Water Level (inches) Infiltration/Percolation Rate 2.75 36.00 72.00 36.00 78.545 0.076 2.50 36.00 72.00 36.00 86.400 0.069 3.00 36.00 72.00 36.00 72.000 0.083 3.00 36.00 72.00 36.00 72.000 0.083 3.75 36.00 72.00 36.00 57.600 0.104 3.50 36.00 72.00 36.00 61.714 0.097 3.75 36.00 72.00 36.00 57.600 0.104 Date:Sep-23 * Based on Prochet Method Percolation Project Number:13629.003 Test Data Project Name:Pulte Explorer Perc BasinsP-4 0.000 20.000 40.000 60.000 80.000 100.000 120.000 0 10 20 30 40 50 60 70 80 90 100 Infiltration Rate (in./hr) Time (min) APPENDIX B LABORATORY TEST RESULTS B-1 Sep-230:94 :6 Project Name: PARTICLE - SIZE DISTRIBUTION ASTM D 6913 Soil Identification:Poorly Graded Sand with Silt (SP-SM), Yellowish Brown. SP-SM GR:SA:FI : (%) Boring No.: Depth (feet):8.0 - 10.0 SAND SILT FINE HYDROMETER Pulte Del Webb Explore Perc Testing Project No.:P-1 Sample No.: Soil Type :13629.003 3.0" 1 1/2" 3/4" 3/8" #4 #8 #16 #30 #50 #100 #200 U.S. STANDARD SIEVE OPENING U.S. STANDARD SIEVE NUMBER GRAVEL FINES FINE CLAY COARSE COARSE MEDIUM 0 10 20 30 40 50 60 70 80 90 100 0.0010.0100.1001.00010.000100.000 PE R C E N T F I N E R B Y W E I G H T PARTICLE - SIZE (mm) " Sieve; P-1, B-1 (09-18-23) B-1 Sep-230:92 :8 Project Name: PARTICLE - SIZE DISTRIBUTION ASTM D 6913 Soil Identification:Poorly Graded Sand with Silt (SP-SM), Yellowish Brown. SP-SM GR:SA:FI : (%) Boring No.: Depth (feet):0 - 8.0 SAND SILT FINE HYDROMETER Pulte Del Webb Explore Perc Testing Project No.:P-3 Sample No.: Soil Type :13629.003 3.0" 1 1/2" 3/4" 3/8" #4 #8 #16 #30 #50 #100 #200 U.S. STANDARD SIEVE OPENING U.S. STANDARD SIEVE NUMBER GRAVEL FINES FINE CLAY COARSE COARSE MEDIUM 0 10 20 30 40 50 60 70 80 90 100 0.0010.0100.1001.00010.000100.000 PE R C E N T F I N E R B Y W E I G H T PARTICLE - SIZE (mm) " Sieve; P-3, B-1 (09-18-23) Tract No. 38434 / Explore Palm Desert Mass/Rough Grading Hydrology Report Appendix F Proposed Land Use Areas RCWRR WQMP Land Use Areas On-Site Retention Basin Summary Client/Project PULTE - TTM 38434 MSA JOB #2636 DRAINAGE AREA S.F. - DETACHED OPEN/LANDSCAPING PAVING/HARDSCAPE RECREATION CENTER S.F. - ATTACHED TOTAL 50% IMPERVIOUS 10% IMPERVIOUS 100% IMPERVIOUS 60% IMPERVIOUS 65% IMPERVIOUS RI=32 RI=32 RI=32 RI=32 RI=32 (acres)(acres)(acres)(acres)(acres)(acres) DA-A 2.5276 0.5830 0.8028 3.9134 DA-B 3.0911 0.4195 1.1534 4.6640 DA-C 2.6240 0.3636 1.0268 4.0144 DA-D 2.6130 0.5480 1.1842 4.3452 DA-E 5.2593 0.9945 2.1547 2.1846 10.5931 DA-F 2.1656 0.5811 1.0966 3.8433 DA-G 22.8640 6.2417 14.1615 1.0925 44.3597 DA-H 2.4633 2.4633 DA-I 1.3316 1.3316 DA-J 14.2822 14.2822 TOTAL SITE 41.1446 13.5263 21.5800 3.2771 14.2822 93.8102 TOTAL PROJECT AREA 93.8102 TOTAL HYDROLOGIC AREA 93.8102 LAND USE PROPOSED LAND USE AREAS - SYNTHETIC UNIT January 10, 2024 HYDROLOGIC SOIL GROUP "A" Client/Project PULTE - TTM 38434 MSA JOB #2636 DRAINAGE AREA S.F. - DETACHED OPEN/LANDSCAPING PAVING/HARDSCAPE RECREATION CENTER S.F. - ATTACHED TOTAL WQMP 50% IMPERVIOUS 10% IMPERVIOUS 100% IMPERVIOUS 60% IMPERVIOUS 65% IMPERVIOUS TOTAL RI=32 RI=32 RI=32 RI=32 RI=32 (acres)(acres)(acres)(acres)(acres)(acres)(acres) DA-A 2.5276 0.5830 0.8028 3.9134 2.1249 DA-B 3.0911 0.4195 1.1534 4.6640 2.7409 DA-C 2.6240 0.3635 1.0268 4.0143 2.37515 DA-D 2.6130 0.5480 1.1842 4.3452 2.5455 DA-E 5.2593 0.9945 2.1547 2.1846 10.5931 6.19456 DA-F 2.1656 0.5811 1.0966 3.8433 2.23751 DA-G 22.8640 6.2417 14.1615 1.0925 44.3597 26.87317 DA-H 2.4634 2.4634 0.24634 DA-I 1.3316 1.3316 0.13316 DA-J 14.2822 14.2822 9.28343 TOTAL SITE 41.1446 13.5263 21.5800 3.2771 14.2822 93.8102 54.7546 TOTAL PROJECT AREA 93.8102 TOTAL WQMP AREA 54.7546 LAND USE WQMP LAND USE - IMPERVIOUS AREAS January 10, 2024 HYDROLOGIC SOIL GROUP "A" PROJECT:PULTE - REFUGE JOB #:2636 DATE:1/9/2024 RETENTION BASIN STORAGE DRAINAGE BASIN RETENTION BASIN VOLUME A 14,885 1 HR 28,552 B 18,169 1 HR 35,231 C 15,812 1HR 27,883 D 16,876 1HR 27,842 E 38,942 1HR 81,261 F 11,046 1 HR 32,102 G 182,055 1 HR 260,199 H 6,199 1 HR 67,641 I 3,129 1 HR 45,419 J 55,542 1 HR 163,193 TOTAL 362,655 769,323 100 YR FLOOD VOLUME ON-SITE RETENTION BASIN SUMMARY 1.52 (Saftey Factor) Tract No. 38434 / Explore Palm Desert Mass/Rough Grading Hydrology Report Appendix G RCFCD Synthetic Unit Hydrograph Worksheets CONTECH DYODS Underground Retention Worksheets RJB 2 AMC II AREA SOIL TRIBUTARY AREAS ACRES LOW LOSS RI INFILTRATION IMPERVIOUS DESIG GROUP CONDITION NUMBER RATE PERCENT 4 A SF - DETACHED 2.527 D 32 0.74 0.50 9 A LANDSCAPING 0.583 D 32 0.74 0.10 2 A PAVING/HARDSCAPE 0.803 D 32 0.74 1.00 755 ft 375 ft 303.7 ft ELEVATION OF CONCENTRATION POINT 299.0 ft 0.02 100 LOW LOSS RATE (Storm Events > 10 Years)85% POINT RAIN FROM NOAA ATLAS 14 1-HOUR 1.57 in 3-HOUR 2.27 in 6-HOUR 2.98 in 24-HOUR 4.59 in BASIN CHARACTERISTICS:ELEVATION AREA 294.5 ft 3,381 sf 295.0 ft 3,862 sf 296.0 ft 5,313 sf 297.0 ft 6,668 sf 298.0 ft 8,079 sf 299.0 ft 9,550 sf PERCOLATION RATE (in/hr)5.0 in/hr DRYWELL DATA NUMBER USED PERCOLATION RATE LOWEST FLOWLINE ELEVATION 299.00 LOWEST PAD ELEVATION 301.1 LENGTH OF WATERCOURSE (L) AREA DESIGNATION ELEVATION OF HEADWATER AVERAGE MANNINGS 'N' VALUE STORM FREQUENCY (YEAR) LENGTH TO POINT OPPOSITE CENTROID (Lca) Low Loss Conditions: X=Existing; D=Developed; BS=Retention DA-A RCFCD SYNTHETIC UNIT HYDROGRAPH - SHORTCUT METHOD DATA INPUT SHEET WORKSHEET PREPARED BY: PROJECT NAME DATE January 9, 2024 Del Webb Explore at Palm Desert PROJECT NUMBER CONCENTRATION POINT DESIGNATION 2636 Retention Basin - A AMC NUMBER Data Input Sheet Page 1 of 13 PROJECT: Job No.: BY:DATE:1/9/24 [1] AMC II [2] FREQUENCY-YEARS 100 FROM NOAA ATLAS 14 [3] STORM DURATION:Point Rain 1-HOUR 1.57 in 3-HOUR 2.27 in 6-HOUR 2.98 in 24-HOUR 4.59 in STORM DURATION 1-HOUR 3-HOUR 6-HOUR 24-HOUR RAINFALL VOLUME (cu-ft)22,301 32,244 42,329 65,197 SOIL LOSSES (cu-ft)5,374 15,510 25,021 50,699 EFFECTIVE RAIN (in)1.19 1.18 1.22 1.02 FLOOD VOLUME (cu-ft)16,926 16,734 17,308 14,499 (acre-ft)0.39 0.38 0.40 0.33 REQUIRED STORAGE (cu-ft)14,885 12,227 11,241 2,696 (acre-ft)0.34 0.28 0.26 0.06 FACTOR OF SAFETY 1.92 2.33 2.54 10.58 STORAGE PROVIDED (cu-ft) (acre-ft) PEAK FLOW (cfs)n/a 7.32 6.41 1.18 MAXIMUM WSEL (ft)297.34 296.98 296.81 295.19 DEPTH (ft)2.84 2.48 2.31 0.69 DIFFERENCE (ft)1.66 2.02 2.19 3.81 DIFFERENCE (ft)3.76 4.12 4.29 5.91 ESTIMATED TIME TO DEWATER BASIN Based on Total Flood Volume & Average Percolation Rate (days)0.3 0.4 0.6 1.0 [18] 200% OF LAG-MINUTES RAINFALL DATA 5.2 NOTE: PEAK FLOW FOR THE 1-HOUR STORM IS NOT REPRESENTATIVE. PER RCFCD PEAK DISCHARGES FROM THE 3-HOUR STORM SHOULD NORMALLY COMPARE WELL WITH RATIONAL PEAKS. LOWEST PAD ELEVATION LOWEST FLOWLINE ELEVATION STORM EVENT SUMMARY 301.1 299.00 28,522 0.65 0.02 [17] 100% OF LAG-MINUTES 2.6 2.6 [14] AVERAGE MANNINGS 'N' [15] LAG TIME-HOURS 0.04 [16] LAG TIME-MINUTES [13] L*LCA/S^0.5 5.73 [11] S-FEET/MILE [6] La-FEET [7] La-MILES [8] ELEVATION OF HEADWATER 0.002 375.00 [12] S^0.5 0.071 32.9 303.7 299 4.7 [3] AREA - ACRES [4] L-FEET [5] L-MILES 755 0.143 Retention Basin - A DA-A Del Webb Explore at Palm Desert [10] H-FEET [9] ELEVATION OF CONCENTRATION POINT 3.913 PHYSICAL DATA [1] CONCENTRATION POINT HYDROLOGY MANUAL BASIC DATA CALCULATION FORM 2636 RJB RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD [2] AREA DESIGNATION Plate E-2.1 Page 2 of 13 PROJECT: Job No.: BY:DATE:1/9/24 MAX LOW LOW MIN SOIL RI PERVIOUS DECIMAL ADJUSTED AREA AREA AVERAGE LOSS LOSS RATE AVERAGE GROUP NUMBER AREA PERCENT INFILTRATION WEIGHTED ADJUSTED CONDITION PER ADJUSTED INFILTRATION OF AREA RATE AVERAGE INFILTRATION RCFC/2322 INFILTRATION RATE IMPERVIOUS RATE RATE (in/hr)(in/hr)(in/hr) [Plate C-1][Plate E-6.1][Plate E-6.2][Plate E-6.3] A 32 0.74 50%0.41 2.527 0.646 0.2628 DEVELOPED 0.5000 0.3229 A 32 0.74 10%0.67 0.583 0.149 0.1003 DEVELOPED 0.8200 0.1222 A 32 0.74 100%0.07 0.803 0.205 0.0152 DEVELOPED 0.1000 0.0205 SUM 3.913 SUM 0.3784 0.4656 VARIABLE LOSS RATE CURVE (24-HOUR STORM ONLY) Fm=0.189177511 NOTE: Low loss rates established per RCFC/2322 (Dated: May-30-95) C=0.00350 For 10 Year Storms or Less Ft=C(24-(T/60))^1.55+Fm =0.00350 0.19 in/hr Undeveloped Condition: Low Loss = 90% CONSTANT LOSS RATE (3 & 6 HOUR STORMS)=0.3784 Developed Condition: Low Loss = 0.9 - (0.8 * %impervious) LOW LOSS RATE =0.8500 Basin Site: Low Loss = 10% Where:For 100 Year Storm - Low Loss should be between 80% & 90% T=Time in minutes. To get an average value for each unit time period, Use T=1/2 the unit time for the first time period,of the Rainfall Rate T=1 1/2 unit time for the second period, etc. (24-(T/60))^1.55 + LAND USE SF - DETACHED LANDSCAPING PAVING/HARDSCAPE AVERAGE ADJUSTED LOSS RATE RCFC & WCD HYDROLOGY MANUAL SYNTHETIC UNIT HYDROGRAPH METHOD BASIC DATA CALCULATION FORM Del Webb Explore at Palm Desert RJB 2636 AMC II Plate E-2.1 Page 3 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 3.91 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 2.59 Maxwell Drywells UNIT TIME-PERCENT OF LAG 192.8 Number 0 TOTAL ADJUSTED STORM RAIN-INCHES 1.57 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE-in/hr 0.38 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 5 0.08 3.6 0.68 0.38 0.58 0.30 1.18 355 355 3,475 121 121 234 0.01 294.56 2 10 0.17 4.2 0.79 0.38 0.67 0.41 1.63 489 723 3,573 124 124 599 0.01 294.67 3 15 0.25 4.4 0.83 0.38 0.70 0.45 1.78 533 1,132 3,682 128 128 1,005 0.02 294.78 4 20 0.33 4.6 0.87 0.38 0.74 0.49 1.93 578 1,583 3,802 132 132 1,451 0.03 294.90 5 25 0.42 5.0 0.94 0.38 0.80 0.56 2.22 667 2,118 3,960 137 137 1,980 0.05 295.04 6 30 0.50 5.6 1.06 0.38 0.90 0.68 2.67 801 2,781 4,171 145 145 2,636 0.06 295.18 7 35 0.58 6.4 1.21 0.38 1.02 0.83 3.26 979 3,616 4,436 154 154 3,462 0.08 295.36 8 40 0.67 8.1 1.53 0.38 1.30 1.15 4.53 1,358 4,820 4,818 167 167 4,653 0.11 295.62 9 45 0.75 13.1 2.47 0.38 2.10 2.09 8.25 2,474 7,126 5,483 190 190 6,936 0.16 296.09 10 50 0.83 34.5 6.50 0.38 5.52 6.12 24.15 7,246 14,182 7,018 244 244 13,938 0.32 297.21 11 55 0.92 6.7 1.26 0.38 1.07 0.88 3.49 1,046 14,985 7,172 249 249 14,736 0.34 297.32 12 60 1.00 3.8 0.72 0.38 0.61 0.34 1.33 400 15,135 7,201 250 250 14,885 0.34 297.34 TOTAL RAINFALL 1.57 in RAINFALL VOLUME 22,301 cu-ft SOIL LOSSES 5,374 cu-ft EFFECTIVE RAIN 1.19 in FLOOD VOLUME 0.39 acft FLOOD VOLUME 16,926 cu-ft REQUIRED STORAGE 0.34 REQUIRED STORAGE 14,885 cu-ft MAX WSEL 297.34 ft PEAK FLOW RATE 24.15 cfs TOTAL BASIN LOSSES 2,041 cu-ft AVERAGE PERCOLATION RATE 34.02 cf/min EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Total In Basin in/hr Time Loss Rate Basin Losses Del Webb Explore at Palm DesertRCFC & WCD HYDROLOGY MANUAL SYNTHETIC UNIT HYDROGRAPH METHOD SHORTCUT METHOD 1-HOUR STORM Plate E-2.2 1-Hour Storm Page 4 of 13 PROJECT: Job No.:2636 BY:RJB DATE DRAINAGE AREA-ACRES 3.91 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 2.59 Maxwell Drywells UNIT TIME-PERCENT OF LAG 192.8 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.27 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.38 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 5 0.08 1.3 0.35 0.38 0.30 0.05 0.21 63 63 3,397 118 63 0 0.00 294.50 2 10 0.17 1.3 0.35 0.38 0.30 0.05 0.21 63 63 3,397 118 63 0 0.00 294.50 3 15 0.25 1.1 0.30 0.38 0.25 0.04 0.18 53 53 3,395 118 53 0 0.00 294.50 4 20 0.33 1.5 0.41 0.38 0.35 0.03 0.12 36 36 3,390 118 36 0 0.00 294.50 5 25 0.42 1.5 0.41 0.38 0.35 0.03 0.12 36 36 3,390 118 36 0 0.00 294.50 6 30 0.50 1.8 0.49 0.38 0.42 0.11 0.44 133 133 3,416 119 119 14 0.00 294.50 7 35 0.58 1.5 0.41 0.38 0.35 0.03 0.12 36 50 3,394 118 50 0 0.00 294.50 8 40 0.67 1.8 0.49 0.38 0.42 0.11 0.44 133 133 3,416 119 119 14 0.00 294.50 9 45 0.75 1.8 0.49 0.38 0.42 0.11 0.44 133 146 3,420 119 119 28 0.00 294.51 10 50 0.83 1.5 0.41 0.38 0.35 0.03 0.12 36 64 3,398 118 64 0 0.00 294.50 11 55 0.92 1.6 0.44 0.38 0.37 0.06 0.23 68 68 3,399 118 68 0 0.00 294.50 12 60 1.00 1.8 0.49 0.38 0.42 0.11 0.44 133 133 3,416 119 119 14 0.00 294.50 13 65 1.08 2.2 0.60 0.38 0.51 0.22 0.87 262 275 3,454 120 120 155 0.00 294.54 14 70 1.17 2.2 0.60 0.38 0.51 0.22 0.87 262 417 3,492 121 121 296 0.01 294.58 15 75 1.25 2.2 0.60 0.38 0.51 0.22 0.87 262 557 3,529 123 123 435 0.01 294.62 16 80 1.33 2.0 0.54 0.38 0.46 0.17 0.66 197 632 3,549 123 123 509 0.01 294.64 17 85 1.42 2.6 0.71 0.38 0.60 0.33 1.30 390 899 3,620 126 126 773 0.02 294.71 18 90 1.50 2.7 0.74 0.38 0.63 0.36 1.41 423 1,196 3,699 128 128 1,068 0.02 294.80 19 95 1.58 2.4 0.65 0.38 0.56 0.28 1.09 326 1,394 3,751 130 130 1,263 0.03 294.85 20 100 1.67 2.7 0.74 0.38 0.63 0.36 1.41 423 1,686 3,829 133 133 1,553 0.04 294.93 21 105 1.75 3.3 0.90 0.38 0.76 0.52 2.05 616 2,169 3,976 138 138 2,031 0.05 295.05 22 110 1.83 3.1 0.84 0.38 0.72 0.47 1.84 552 2,583 4,108 143 143 2,440 0.06 295.14 23 115 1.92 2.9 0.79 0.38 0.67 0.41 1.62 487 2,928 4,217 146 146 2,781 0.06 295.21 24 120 2.00 3.0 0.82 0.38 0.69 0.44 1.73 519 3,301 4,336 151 151 3,150 0.07 295.29 25 125 2.08 3.1 0.84 0.38 0.72 0.47 1.84 552 3,702 4,463 155 155 3,547 0.08 295.38 RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 3-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Loss Rate Basin Losses Plate E-2.2 3-Hour Storm Page 5 of 13 PROJECT: Job No.:2636 BY:RJB DATE DRAINAGE AREA-ACRES 3.91 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 2.59 Maxwell Drywells UNIT TIME-PERCENT OF LAG 192.8 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.27 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.38 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 3-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Loss Rate Basin Losses 26 130 2.17 4.2 1.14 0.38 0.97 0.77 3.02 906 4,453 4,702 163 163 4,290 0.10 295.54 27 135 2.25 5.0 1.36 0.38 1.16 0.98 3.88 1,164 5,454 5,020 174 174 5,280 0.12 295.76 28 140 2.33 3.5 0.95 0.38 0.81 0.58 2.27 681 5,961 5,181 180 180 5,781 0.13 295.87 29 145 2.42 6.8 1.85 0.38 1.57 1.47 5.82 1,745 7,525 5,573 194 194 7,332 0.17 296.16 30 150 2.50 7.3 1.99 0.38 1.69 1.61 6.35 1,906 9,238 5,962 207 207 9,031 0.21 296.44 31 155 2.58 8.2 2.23 0.38 1.90 1.86 7.32 2,196 11,227 6,413 223 223 11,004 0.25 296.77 32 160 2.67 5.9 1.61 0.38 1.37 1.23 4.85 1,455 12,459 6,688 232 232 12,227 0.28 296.98 33 165 2.75 2.0 0.54 0.38 0.46 0.17 0.66 197 12,424 6,681 232 232 12,192 0.28 296.97 34 170 2.83 1.8 0.49 0.38 0.42 0.11 0.44 133 12,324 6,661 231 231 12,093 0.28 296.96 35 175 2.92 1.8 0.49 0.38 0.42 0.11 0.44 133 12,225 6,639 231 231 11,995 0.28 296.94 36 180 3.00 0.6 0.16 0.38 0.14 0.02 0.10 29 12,024 6,593 229 229 11,795 0.27 296.91 TOTAL RAIN RAINFALL VOLUME SOIL LOSSES EFFECTIVE RAIN FLOOD VOLUME FLOOD VOLUME REQUIRED STORAGE REQUIRED STORAGE MAX WSEL PEAK FLOW RATE TOTAL BASIN LOSSES AVERAGE PERCOLATION RATE EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY 4,939 cu-ft 27.44 cf/min 1.18 in 0.38 acft 16,734 cu-ft 0.28 acft 12,227 cu-ft 15,510 cu-ft 2.27 in 32,244 cu-ft 296.98 ft 7.32 cfs Plate E-2.2 3-Hour Storm Page 6 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 3.91 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 2.59 Maxwell Drywells UNIT TIME-PERCENT OF LAG 192.8 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.98 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.38 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 5 0.08 0.5 0.18 0.38 0.15 0.03 0.11 32 32 3,389 118 32 0 0.00 294.50 2 10 0.17 0.6 0.21 0.38 0.18 0.03 0.13 38 38 3,391 118 38 0 0.00 294.50 3 15 0.25 0.6 0.21 0.38 0.18 0.03 0.13 38 38 3,391 118 38 0 0.00 294.50 4 20 0.33 0.6 0.21 0.38 0.18 0.03 0.13 38 38 3,391 118 38 0 0.00 294.50 5 25 0.42 0.6 0.21 0.38 0.18 0.03 0.13 38 38 3,391 118 38 0 0.00 294.50 6 30 0.50 0.7 0.25 0.38 0.21 0.04 0.15 44 44 3,393 118 44 0 0.00 294.50 7 35 0.58 0.7 0.25 0.38 0.21 0.04 0.15 44 44 3,393 118 44 0 0.00 294.50 8 40 0.67 0.7 0.25 0.38 0.21 0.04 0.15 44 44 3,393 118 44 0 0.00 294.50 9 45 0.75 0.7 0.25 0.38 0.21 0.04 0.15 44 44 3,393 118 44 0 0.00 294.50 10 50 0.83 0.7 0.25 0.38 0.21 0.04 0.15 44 44 3,393 118 44 0 0.00 294.50 11 55 0.92 0.7 0.25 0.38 0.21 0.04 0.15 44 44 3,393 118 44 0 0.00 294.50 12 60 1.00 0.8 0.29 0.38 0.24 0.04 0.17 51 51 3,394 118 51 0 0.00 294.50 13 65 1.08 0.8 0.29 0.38 0.24 0.04 0.17 51 51 3,394 118 51 0 0.00 294.50 14 70 1.17 0.8 0.29 0.38 0.24 0.04 0.17 51 51 3,394 118 51 0 0.00 294.50 15 75 1.25 0.8 0.29 0.38 0.24 0.04 0.17 51 51 3,394 118 51 0 0.00 294.50 16 80 1.33 0.8 0.29 0.38 0.24 0.04 0.17 51 51 3,394 118 51 0 0.00 294.50 17 85 1.42 0.8 0.29 0.38 0.24 0.04 0.17 51 51 3,394 118 51 0 0.00 294.50 18 90 1.50 0.8 0.29 0.38 0.24 0.04 0.17 51 51 3,394 118 51 0 0.00 294.50 19 95 1.58 0.8 0.29 0.38 0.24 0.04 0.17 51 51 3,394 118 51 0 0.00 294.50 20 100 1.67 0.8 0.29 0.38 0.24 0.04 0.17 51 51 3,394 118 51 0 0.00 294.50 21 105 1.75 0.8 0.29 0.38 0.24 0.04 0.17 51 51 3,394 118 51 0 0.00 294.50 22 110 1.83 0.8 0.29 0.38 0.24 0.04 0.17 51 51 3,394 118 51 0 0.00 294.50 23 115 1.92 0.8 0.29 0.38 0.24 0.04 0.17 51 51 3,394 118 51 0 0.00 294.50 24 120 2.00 0.9 0.32 0.38 0.27 0.05 0.19 57 57 3,396 118 57 0 0.00 294.50 Loss Rate RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 6-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Basin Losses Plate E-2.2 6-Hour Storm Page 7 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 3.91 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 2.59 Maxwell Drywells UNIT TIME-PERCENT OF LAG 192.8 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.98 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.38 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft Loss Rate RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 6-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Basin Losses 25 125 2.08 0.8 0.29 0.38 0.24 0.04 0.17 51 51 3,394 118 51 0 0.00 294.50 26 130 2.17 0.9 0.32 0.38 0.27 0.05 0.19 57 57 3,396 118 57 0 0.00 294.50 27 135 2.25 0.9 0.32 0.38 0.27 0.05 0.19 57 57 3,396 118 57 0 0.00 294.50 28 140 2.33 0.9 0.32 0.38 0.27 0.05 0.19 57 57 3,396 118 57 0 0.00 294.50 29 145 2.42 0.9 0.32 0.38 0.27 0.05 0.19 57 57 3,396 118 57 0 0.00 294.50 30 150 2.50 0.9 0.32 0.38 0.27 0.05 0.19 57 57 3,396 118 57 0 0.00 294.50 31 155 2.58 0.9 0.32 0.38 0.27 0.05 0.19 57 57 3,396 118 57 0 0.00 294.50 32 160 2.67 0.9 0.32 0.38 0.27 0.05 0.19 57 57 3,396 118 57 0 0.00 294.50 33 165 2.75 1.0 0.36 0.38 0.30 0.05 0.21 63 63 3,398 118 63 0 0.00 294.50 34 170 2.83 1.0 0.36 0.38 0.30 0.05 0.21 63 63 3,398 118 63 0 0.00 294.50 35 175 2.92 1.0 0.36 0.38 0.30 0.05 0.21 63 63 3,398 118 63 0 0.00 294.50 36 180 3.00 1.0 0.36 0.38 0.30 0.05 0.21 63 63 3,398 118 63 0 0.00 294.50 37 185 3.08 1.0 0.36 0.38 0.30 0.05 0.21 63 63 3,398 118 63 0 0.00 294.50 38 190 3.17 1.1 0.39 0.38 0.33 0.02 0.06 18 18 3,385 118 18 0 0.00 294.50 39 195 3.25 1.1 0.39 0.38 0.33 0.02 0.06 18 18 3,385 118 18 0 0.00 294.50 40 200 3.33 1.1 0.39 0.38 0.33 0.02 0.06 18 18 3,385 118 18 0 0.00 294.50 41 205 3.42 1.2 0.43 0.38 0.36 0.05 0.20 60 60 3,397 118 60 0 0.00 294.50 42 210 3.50 1.3 0.46 0.38 0.40 0.09 0.34 102 102 3,408 118 102 0 0.00 294.50 43 215 3.58 1.4 0.50 0.38 0.43 0.12 0.48 145 145 3,419 119 119 26 0.00 294.51 44 220 3.67 1.4 0.50 0.38 0.43 0.12 0.48 145 171 3,426 119 119 52 0.00 294.51 45 225 3.75 1.5 0.54 0.38 0.46 0.16 0.62 187 239 3,444 120 120 119 0.00 294.53 46 230 3.83 1.5 0.54 0.38 0.46 0.16 0.62 187 306 3,462 120 120 186 0.00 294.55 47 235 3.92 1.6 0.57 0.38 0.49 0.19 0.76 229 416 3,491 121 121 294 0.01 294.58 48 240 4.00 1.6 0.57 0.38 0.49 0.19 0.76 229 524 3,520 122 122 402 0.01 294.61 49 245 4.08 1.7 0.61 0.38 0.52 0.23 0.91 272 673 3,560 124 124 550 0.01 294.65 50 250 4.17 1.8 0.64 0.38 0.55 0.27 1.05 314 864 3,610 125 125 738 0.02 294.70 Plate E-2.2 6-Hour Storm Page 8 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 3.91 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 2.59 Maxwell Drywells UNIT TIME-PERCENT OF LAG 192.8 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.98 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.38 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft Loss Rate RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 6-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Basin Losses 51 255 4.25 1.9 0.68 0.38 0.58 0.30 1.19 356 1,095 3,672 127 127 967 0.02 294.77 52 260 4.33 2.0 0.72 0.38 0.61 0.34 1.33 399 1,366 3,744 130 130 1,236 0.03 294.84 53 265 4.42 2.1 0.75 0.38 0.64 0.37 1.47 441 1,677 3,827 133 133 1,544 0.04 294.93 54 270 4.50 2.1 0.75 0.38 0.64 0.37 1.47 441 1,985 3,918 136 136 1,849 0.04 295.01 55 275 4.58 2.2 0.79 0.38 0.67 0.41 1.61 483 2,333 4,028 140 140 2,193 0.05 295.08 56 280 4.67 2.3 0.82 0.38 0.70 0.44 1.75 526 2,718 4,151 144 144 2,574 0.06 295.17 57 285 4.75 2.4 0.86 0.38 0.73 0.48 1.89 568 3,142 4,285 149 149 2,993 0.07 295.26 58 290 4.83 2.4 0.86 0.38 0.73 0.48 1.89 568 3,562 4,419 153 153 3,408 0.08 295.35 59 295 4.92 2.5 0.89 0.38 0.76 0.52 2.03 610 4,018 4,564 158 158 3,860 0.09 295.45 60 300 5.00 2.6 0.93 0.38 0.79 0.55 2.18 653 4,513 4,721 164 164 4,349 0.10 295.56 61 305 5.08 3.1 1.11 0.38 0.94 0.73 2.88 864 5,213 4,943 172 172 5,041 0.12 295.71 62 310 5.17 3.6 1.29 0.38 1.09 0.91 3.59 1,076 6,117 5,230 182 182 5,936 0.14 295.90 63 315 5.25 3.9 1.39 0.38 1.19 1.02 4.01 1,203 7,139 5,486 190 190 6,948 0.16 296.10 64 320 5.33 4.2 1.50 0.38 1.28 1.12 4.43 1,330 8,278 5,744 199 199 8,079 0.19 296.28 65 325 5.42 4.7 1.68 0.38 1.43 1.30 5.14 1,542 9,620 6,048 210 210 9,410 0.22 296.51 66 330 5.50 5.6 2.00 0.38 1.70 1.62 6.41 1,923 11,333 6,437 223 223 11,109 0.26 296.79 67 335 5.58 1.9 0.68 0.38 0.58 0.30 1.19 356 11,466 6,467 225 225 11,241 0.26 296.81 68 340 5.67 0.9 0.32 0.38 0.27 0.05 0.19 57 11,298 6,429 223 223 11,075 0.25 296.79 69 345 5.75 0.6 0.21 0.38 0.18 0.03 0.13 38 11,113 6,387 222 222 10,892 0.25 296.76 70 350 5.83 0.5 0.18 0.38 0.15 0.03 0.11 32 10,923 6,344 220 220 10,703 0.25 296.72 71 355 5.92 0.3 0.11 0.38 0.09 0.02 0.06 19 10,722 6,298 219 219 10,503 0.24 296.69 72 360 6.00 0.2 0.07 0.38 0.06 0.01 0.04 13 10,516 6,251 217 217 10,299 0.24 296.66 TOTAL RAINFALL RAINFALL VOLUME SOIL LOSSES EFFECTIVE RAIN FLOOD VOLUME FLOOD VOLUME REQUIRED STORAGE REQUIRED STORAGE MAX WSEL PEAK FLOW RATE TOTAL BASIN LOSSES AVERAGE PERCOLATION RATE EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY 19.47 cf/min 7,009 cu-ft 1.22 in 0.40 acft 17,308 cu-ft 0.26 acft 11,241 cu-ft 42,329 cu-ft 2.98 in 25,021 cu-ft 296.81 ft 6.41 cfs Plate E-2.2 6-Hour Storm Page 9 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 3.91 VARIABLE LOSS RATE (AVG) IN/HR Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 15 Fm = Minimum value on loss curve (in/hr)0.19 LAG TIME - MINUTES 2.59 C 0.00350 Maxwell Drywells UNIT TIME-PERCENT OF LAG 579%Low Loss Rate (percent)85.00%Number 0 TOTAL ADJUSTED STORM RAIN (in)4.59 Drywell Percolation Rate 0.00 cfs 0.00 cfm Unit Time Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 15 0.25 0.2 0.037 0.668 0.031 0.01 0.02 20 20 3,386 353 20 0 0.00 294.50 2 30 0.50 0.3 0.055 0.660 0.047 0.01 0.03 29 29 3,389 353 29 0 0.00 294.50 3 45 0.75 0.3 0.055 0.653 0.047 0.01 0.03 29 29 3,389 353 29 0 0.00 294.50 4 60 1.00 0.4 0.073 0.645 0.062 0.01 0.04 39 39 3,391 353 39 0 0.00 294.50 5 75 1.25 0.3 0.055 0.637 0.047 0.01 0.03 29 29 3,389 353 29 0 0.00 294.50 6 90 1.50 0.3 0.055 0.630 0.047 0.01 0.03 29 29 3,389 353 29 0 0.00 294.50 7 105 1.75 0.3 0.055 0.622 0.047 0.01 0.03 29 29 3,389 353 29 0 0.00 294.50 8 120 2.00 0.4 0.073 0.615 0.062 0.01 0.04 39 39 3,391 353 39 0 0.00 294.50 9 135 2.25 0.4 0.073 0.607 0.062 0.01 0.04 39 39 3,391 353 39 0 0.00 294.50 10 150 2.50 0.4 0.073 0.600 0.062 0.01 0.04 39 39 3,391 353 39 0 0.00 294.50 11 165 2.75 0.5 0.092 0.593 0.078 0.01 0.05 49 49 3,394 354 49 0 0.00 294.50 12 180 3.00 0.5 0.092 0.585 0.078 0.01 0.05 49 49 3,394 354 49 0 0.00 294.50 13 195 3.25 0.5 0.092 0.578 0.078 0.01 0.05 49 49 3,394 354 49 0 0.00 294.50 14 210 3.50 0.5 0.092 0.571 0.078 0.01 0.05 49 49 3,394 354 49 0 0.00 294.50 15 225 3.75 0.5 0.092 0.564 0.078 0.01 0.05 49 49 3,394 354 49 0 0.00 294.50 16 240 4.00 0.6 0.110 0.557 0.094 0.02 0.07 59 59 3,396 354 59 0 0.00 294.50 17 255 4.25 0.6 0.110 0.550 0.094 0.02 0.07 59 59 3,396 354 59 0 0.00 294.50 18 270 4.50 0.7 0.129 0.543 0.109 0.02 0.08 68 68 3,399 354 68 0 0.00 294.50 19 285 4.75 0.7 0.129 0.536 0.109 0.02 0.08 68 68 3,399 354 68 0 0.00 294.50 20 300 5.00 0.8 0.147 0.529 0.125 0.02 0.09 78 78 3,402 354 78 0 0.00 294.50 21 315 5.25 0.6 0.110 0.522 0.094 0.02 0.07 59 59 3,396 354 59 0 0.00 294.50 22 330 5.50 0.7 0.129 0.515 0.109 0.02 0.08 68 68 3,399 354 68 0 0.00 294.50 23 345 5.75 0.8 0.147 0.508 0.125 0.02 0.09 78 78 3,402 354 78 0 0.00 294.50 24 360 6.00 0.8 0.147 0.502 0.125 0.02 0.09 78 78 3,402 354 78 0 0.00 294.50 25 375 6.25 0.9 0.165 0.495 0.140 0.02 0.10 88 88 3,404 355 88 0 0.00 294.50 26 390 6.50 0.9 0.165 0.488 0.140 0.02 0.10 88 88 3,404 355 88 0 0.00 294.50 27 405 6.75 1.0 0.184 0.482 0.156 0.03 0.11 98 98 3,407 355 98 0 0.00 294.50 28 420 7.00 1.0 0.184 0.475 0.156 0.03 0.11 98 98 3,407 355 98 0 0.00 294.50 29 435 7.25 1.0 0.184 0.469 0.156 0.03 0.11 98 98 3,407 355 98 0 0.00 294.50 30 450 7.50 1.1 0.202 0.462 0.172 0.03 0.12 108 108 3,409 355 108 0 0.00 294.50 31 465 7.75 1.2 0.220 0.456 0.187 0.03 0.13 117 117 3,412 355 117 0 0.00 294.50 32 480 8.00 1.3 0.239 0.450 0.203 0.04 0.14 127 127 3,415 356 127 0 0.00 294.50 33 495 8.25 1.5 0.275 0.444 0.234 0.04 0.16 147 147 3,420 356 147 0 0.00 294.50 34 510 8.50 1.5 0.275 0.437 0.234 0.04 0.16 147 147 3,420 356 147 0 0.00 294.50 35 525 8.75 1.6 0.294 0.431 0.250 0.04 0.17 156 156 3,422 356 156 0 0.00 294.50 36 540 9.00 1.7 0.312 0.425 0.265 0.05 0.18 166 166 3,425 357 166 0 0.00 294.50 37 555 9.25 1.9 0.349 0.419 0.297 0.05 0.21 186 186 3,430 357 186 0 0.00 294.50 38 570 9.50 2.0 0.367 0.413 0.312 0.06 0.22 196 196 3,433 358 196 0 0.00 294.50 39 585 9.75 2.1 0.386 0.407 0.328 0.06 0.23 205 205 3,435 358 205 0 0.00 294.50 40 600 10.00 2.2 0.404 0.401 0.343 0.00 0.01 9 9 3,383 352 9 0 0.00 294.50 41 615 10.25 1.5 0.275 0.396 0.234 0.04 0.16 147 147 3,420 356 147 0 0.00 294.50 42 630 10.50 1.5 0.275 0.390 0.234 0.04 0.16 147 147 3,420 356 147 0 0.00 294.50 43 645 10.75 2.0 0.367 0.384 0.312 0.06 0.22 196 196 3,433 358 196 0 0.00 294.50 in/hr Total In Basin UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Loss Rate Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD MANUAL 24-HOUR STORM Basin Losses Plate E-2.2 24-Hour Storm Page 10 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 3.91 VARIABLE LOSS RATE (AVG) IN/HR Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 15 Fm = Minimum value on loss curve (in/hr)0.19 LAG TIME - MINUTES 2.59 C 0.00350 Maxwell Drywells UNIT TIME-PERCENT OF LAG 579%Low Loss Rate (percent)85.00%Number 0 TOTAL ADJUSTED STORM RAIN (in)4.59 Drywell Percolation Rate 0.00 cfs 0.00 cfm Unit Time Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft in/hr Total In Basin UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Loss Rate Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD MANUAL 24-HOUR STORM Basin Losses 44 660 11.00 2.0 0.367 0.379 0.312 0.06 0.22 196 196 3,433 358 196 0 0.00 294.50 45 675 11.25 1.9 0.349 0.373 0.297 0.05 0.21 186 186 3,430 357 186 0 0.00 294.50 46 690 11.50 1.9 0.349 0.368 0.297 0.05 0.21 186 186 3,430 357 186 0 0.00 294.50 47 705 11.75 1.7 0.312 0.362 0.265 0.05 0.18 166 166 3,425 357 166 0 0.00 294.50 48 720 12.00 1.8 0.330 0.357 0.281 0.05 0.20 176 176 3,428 357 176 0 0.00 294.50 49 735 12.25 2.5 0.459 0.351 0.390 0.11 0.42 382 382 3,482 363 363 19 0.00 294.51 50 750 12.50 2.6 0.477 0.346 0.406 0.13 0.52 466 485 3,510 366 366 120 0.00 294.53 51 765 12.75 2.8 0.514 0.341 0.437 0.17 0.68 615 734 3,576 373 373 362 0.01 294.60 52 780 13.00 2.9 0.532 0.336 0.453 0.20 0.78 698 1,060 3,663 382 382 679 0.02 294.69 53 795 13.25 3.4 0.624 0.331 0.531 0.29 1.16 1,042 1,721 3,838 400 400 1,321 0.03 294.87 54 810 13.50 3.4 0.624 0.326 0.531 0.30 1.18 1,060 2,381 4,044 421 421 1,960 0.04 295.03 55 825 13.75 2.3 0.422 0.321 0.359 0.10 0.40 360 2,320 4,024 419 419 1,901 0.04 295.02 56 840 14.00 2.3 0.422 0.316 0.359 0.11 0.42 378 2,279 4,011 418 418 1,861 0.04 295.01 57 855 14.25 2.7 0.496 0.311 0.421 0.18 0.73 656 2,517 4,087 426 426 2,091 0.05 295.06 58 870 14.50 2.6 0.477 0.306 0.406 0.17 0.67 607 2,698 4,144 432 432 2,267 0.05 295.10 59 885 14.75 2.6 0.477 0.302 0.406 0.18 0.69 624 2,891 4,205 438 438 2,453 0.06 295.14 60 900 15.00 2.5 0.459 0.297 0.390 0.16 0.64 575 3,028 4,249 443 443 2,585 0.06 295.17 61 915 15.25 2.4 0.441 0.292 0.375 0.15 0.58 526 3,111 4,276 445 445 2,666 0.06 295.19 62 930 15.50 2.3 0.422 0.288 0.359 0.13 0.53 477 3,143 4,285 446 446 2,696 0.06 295.19 63 945 15.75 1.9 0.349 0.284 0.297 0.07 0.26 232 2,928 4,217 439 439 2,489 0.06 295.15 64 960 16.00 1.9 0.349 0.279 0.297 0.07 0.27 247 2,736 4,156 433 433 2,303 0.05 295.11 65 975 16.25 0.4 0.073 0.275 0.062 0.01 0.04 39 2,342 4,031 420 420 1,922 0.04 295.02 66 990 16.50 0.4 0.073 0.271 0.062 0.01 0.04 39 1,961 3,910 407 407 1,554 0.04 294.93 67 1005 16.75 0.3 0.055 0.267 0.047 0.01 0.03 29 1,583 3,802 396 396 1,187 0.03 294.83 68 1020 17.00 0.3 0.055 0.263 0.047 0.01 0.03 29 1,216 3,704 386 386 831 0.02 294.73 69 1035 17.25 0.5 0.092 0.259 0.078 0.01 0.05 49 879 3,615 377 377 503 0.01 294.64 70 1050 17.50 0.5 0.092 0.255 0.078 0.01 0.05 49 552 3,527 367 367 184 0.00 294.55 71 1065 17.75 0.5 0.092 0.251 0.078 0.01 0.05 49 233 3,443 359 233 0 0.00 294.50 72 1080 18.00 0.4 0.073 0.247 0.062 0.01 0.04 39 39 3,391 353 39 0 0.00 294.50 73 1095 18.25 0.4 0.073 0.244 0.062 0.01 0.04 39 39 3,391 353 39 0 0.00 294.50 74 1110 18.50 0.4 0.073 0.240 0.062 0.01 0.04 39 39 3,391 353 39 0 0.00 294.50 75 1125 18.75 0.3 0.055 0.237 0.047 0.01 0.03 29 29 3,389 353 29 0 0.00 294.50 76 1140 19.00 0.2 0.037 0.233 0.031 0.01 0.02 20 20 3,386 353 20 0 0.00 294.50 77 1155 19.25 0.3 0.055 0.230 0.047 0.01 0.03 29 29 3,389 353 29 0 0.00 294.50 78 1170 19.50 0.4 0.073 0.227 0.062 0.01 0.04 39 39 3,391 353 39 0 0.00 294.50 79 1185 19.75 0.3 0.055 0.224 0.047 0.01 0.03 29 29 3,389 353 29 0 0.00 294.50 80 1200 20.00 0.2 0.037 0.221 0.031 0.01 0.02 20 20 3,386 353 20 0 0.00 294.50 81 1215 20.25 0.3 0.055 0.218 0.047 0.01 0.03 29 29 3,389 353 29 0 0.00 294.50 82 1230 20.50 0.3 0.055 0.215 0.047 0.01 0.03 29 29 3,389 353 29 0 0.00 294.50 83 1245 20.75 0.3 0.055 0.212 0.047 0.01 0.03 29 29 3,389 353 29 0 0.00 294.50 84 1260 21.00 0.2 0.037 0.210 0.031 0.01 0.02 20 20 3,386 353 20 0 0.00 294.50 85 1275 21.25 0.3 0.055 0.207 0.047 0.01 0.03 29 29 3,389 353 29 0 0.00 294.50 86 1290 21.50 0.2 0.037 0.205 0.031 0.01 0.02 20 20 3,386 353 20 0 0.00 294.50 Plate E-2.2 24-Hour Storm Page 11 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 3.91 VARIABLE LOSS RATE (AVG) IN/HR Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 15 Fm = Minimum value on loss curve (in/hr)0.19 LAG TIME - MINUTES 2.59 C 0.00350 Maxwell Drywells UNIT TIME-PERCENT OF LAG 579%Low Loss Rate (percent)85.00%Number 0 TOTAL ADJUSTED STORM RAIN (in)4.59 Drywell Percolation Rate 0.00 cfs 0.00 cfm Unit Time Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft in/hr Total In Basin UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Loss Rate Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD MANUAL 24-HOUR STORM Basin Losses 87 1305 21.75 0.3 0.055 0.203 0.047 0.01 0.03 29 29 3,389 353 29 0 0.00 294.50 88 1320 22.00 0.2 0.037 0.200 0.031 0.01 0.02 20 20 3,386 353 20 0 0.00 294.50 89 1335 22.25 0.3 0.055 0.198 0.047 0.01 0.03 29 29 3,389 353 29 0 0.00 294.50 90 1350 22.50 0.2 0.037 0.197 0.031 0.01 0.02 20 20 3,386 353 20 0 0.00 294.50 91 1365 22.75 0.2 0.037 0.195 0.031 0.01 0.02 20 20 3,386 353 20 0 0.00 294.50 92 1380 23.00 0.2 0.037 0.193 0.031 0.01 0.02 20 20 3,386 353 20 0 0.00 294.50 93 1395 23.25 0.2 0.037 0.192 0.031 0.01 0.02 20 20 3,386 353 20 0 0.00 294.50 94 1410 23.50 0.2 0.037 0.191 0.031 0.01 0.02 20 20 3,386 353 20 0 0.00 294.50 95 1425 23.75 0.2 0.037 0.190 0.031 0.01 0.02 20 20 3,386 353 20 0 0.00 294.50 96 1440 24.00 0.2 0.037 0.189 0.031 0.01 0.02 20 20 3,386 353 20 0 0.00 294.50 EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY TOTAL RAINFALL RAINFALL VOLUME SOIL LOSSES EFFECTIVE RAIN FLOOD VOLUME FLOOD VOLUME REQUIRED STORAGE REQUIRED STORAGE MAX WSEL PEAK FLOW RATE TOTAL BASIN LOSSES AVERAGE PERCOLATION RATE 14,499 cu-ft 10.07 cf/min 1.02 in 0.33 acft 14,499 cu-ft 0.06 acft 2,696 cu-ft 4.59 in 65,197 cu-ft 50,699 cu-ft 295.19 ft 1.18 cfs Plate E-2.2 24-Hour Storm Page 12 of 13 PROECT JOB No. BASIN DESIGNATION: BASIN CHARACTERISTICS CONTOUR ELEVATION INCR TOTAL INCR TOTAL INCR (ft)(ft)(sf)(sf)(cuft)(cuft)(acre-ft) 294.5 0 0 3,381 0 0 0.00 295 0.5 0.5 481 3,862 1,809 1,809 0.04 296 1 1.5 1,451 5,313 4,568 6,378 0.15 297 1 2.5 1,355 6,668 5,978 12,356 0.28 298 1 3.5 1,411 8,079 7,363 19,718 0.45 299 1 4.5 1,471 9,550 8,804 28,522 0.65 WHERE: TOTAL Retention Basin - A BASIN VOLUME WORKSHEET DEPTH AREA VOLUME Del Webb Explore at Palm Desert 2636 ()()2121213 1 AAAAEEV++−= Basin Volume Worksheet Page 13 of 13 RJB 2 AMC II AREA SOIL TRIBUTARY AREAS ACRES LOW LOSS RI INFILTRATION IMPERVIOUS DESIG GROUP CONDITION NUMBER RATE PERCENT 4 A SF - DETACHED 3.091 D 32 0.74 0.50 9 A LANDSCAPING 0.420 D 32 0.74 0.10 2 A PAVING/HARDSCAPE 1.153 D 32 0.74 1.00 958 ft 479 ft 303.7 ft ELEVATION OF CONCENTRATION POINT 297.5 ft 0.02 100 LOW LOSS RATE (Storm Events > 10 Years)85% POINT RAIN FROM NOAA ATLAS 14 1-HOUR 1.57 in 3-HOUR 2.27 in 6-HOUR 2.98 in 24-HOUR 4.59 in BASIN CHARACTERISTICS:ELEVATION AREA 294.5 ft 3,819 sf 295.0 ft 4,730 sf 296.0 ft 6,513 sf 297.0 ft 8,246 sf 298.0 ft 10,104 sf 299.0 ft 11,876 sf PERCOLATION RATE (in/hr)5.0 in/hr DRYWELL DATA NUMBER USED PERCOLATION RATE LOWEST FLOWLINE ELEVATION 297.47 LOWEST PAD ELEVATION 299.6 LENGTH OF WATERCOURSE (L) AREA DESIGNATION ELEVATION OF HEADWATER AVERAGE MANNINGS 'N' VALUE STORM FREQUENCY (YEAR) LENGTH TO POINT OPPOSITE CENTROID (Lca) Low Loss Conditions: X=Existing; D=Developed; BS=Retention DA-B RCFCD SYNTHETIC UNIT HYDROGRAPH - SHORTCUT METHOD DATA INPUT SHEET WORKSHEET PREPARED BY: PROJECT NAME DATE January 9, 2024 Del Webb Explore at Palm Desert PROJECT NUMBER CONCENTRATION POINT DESIGNATION 2636 Retention Basin-B AMC NUMBER Data Input Sheet Page 1 of 13 PROJECT: Job No.: BY:DATE:1/9/24 [1] AMC II [2] FREQUENCY-YEARS 100 FROM NOAA ATLAS 14 [3] STORM DURATION:Point Rain 1-HOUR 1.57 in 3-HOUR 2.27 in 6-HOUR 2.98 in 24-HOUR 4.59 in STORM DURATION 1-HOUR 3-HOUR 6-HOUR 24-HOUR RAINFALL VOLUME (cu-ft)26,581 38,432 50,453 77,710 SOIL LOSSES (cu-ft)5,902 17,278 28,879 59,738 EFFECTIVE RAIN (in)1.22 1.25 1.27 1.06 FLOOD VOLUME (cu-ft)20,679 21,154 21,573 17,973 (acre-ft)0.47 0.49 0.50 0.41 REQUIRED STORAGE (cu-ft)18,169 15,372 14,290 4,261 (acre-ft)0.42 0.35 0.33 0.10 FACTOR OF SAFETY 1.94 2.29 2.47 8.27 STORAGE PROVIDED (cu-ft) (acre-ft) PEAK FLOW (cfs)n/a 8.87 7.78 1.52 MAXIMUM WSEL (ft)297.34 297.03 296.89 295.38 DEPTH (ft)2.84 2.53 2.39 0.88 DIFFERENCE (ft)0.13 0.44 0.58 2.09 DIFFERENCE (ft)2.26 2.57 2.71 4.22 ESTIMATED TIME TO DEWATER BASIN Based on Total Flood Volume & Average Percolation Rate (days)0.3 0.4 0.6 1.0 [18] 200% OF LAG-MINUTES RAINFALL DATA 6.2 NOTE: PEAK FLOW FOR THE 1-HOUR STORM IS NOT REPRESENTATIVE. PER RCFCD PEAK DISCHARGES FROM THE 3-HOUR STORM SHOULD NORMALLY COMPARE WELL WITH RATIONAL PEAKS. LOWEST PAD ELEVATION LOWEST FLOWLINE ELEVATION STORM EVENT SUMMARY 299.6 297.47 35,230 0.81 0.02 [17] 100% OF LAG-MINUTES 3.1 3.1 [14] AVERAGE MANNINGS 'N' [15] LAG TIME-HOURS 0.05 [16] LAG TIME-MINUTES [13] L*LCA/S^0.5 5.85 [11] S-FEET/MILE [6] La-FEET [7] La-MILES [8] ELEVATION OF HEADWATER 0.003 479.00 [12] S^0.5 0.091 34.2 303.7 297.5 6.2 [3] AREA - ACRES [4] L-FEET [5] L-MILES 958 0.181 Retention Basin-B DA-B Del Webb Explore at Palm Desert [10] H-FEET [9] ELEVATION OF CONCENTRATION POINT 4.664 PHYSICAL DATA [1] CONCENTRATION POINT HYDROLOGY MANUAL BASIC DATA CALCULATION FORM 2636 RJB RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD [2] AREA DESIGNATION Plate E-2.1 Page 2 of 13 PROJECT: Job No.: BY:DATE:1/9/24 MAX LOW LOW MIN SOIL RI PERVIOUS DECIMAL ADJUSTED AREA AREA AVERAGE LOSS LOSS RATE AVERAGE GROUP NUMBER AREA PERCENT INFILTRATION WEIGHTED ADJUSTED CONDITION PER ADJUSTED INFILTRATION OF AREA RATE AVERAGE INFILTRATION RCFC/2322 INFILTRATION RATE IMPERVIOUS RATE RATE (in/hr)(in/hr)(in/hr) [Plate C-1][Plate E-6.1][Plate E-6.2][Plate E-6.3] A 32 0.74 50%0.41 3.091 0.663 0.2697 DEVELOPED 0.5000 0.3314 A 32 0.74 10%0.67 0.420 0.090 0.0606 DEVELOPED 0.8200 0.0738 A 32 0.74 100%0.07 1.153 0.247 0.0183 DEVELOPED 0.1000 0.0247 SUM 4.664 SUM 0.3486 0.4299 VARIABLE LOSS RATE CURVE (24-HOUR STORM ONLY) Fm=0.174305382 NOTE: Low loss rates established per RCFC/2322 (Dated: May-30-95) C=0.00323 For 10 Year Storms or Less Ft=C(24-(T/60))^1.55+Fm =0.00323 0.17 in/hr Undeveloped Condition: Low Loss = 90% CONSTANT LOSS RATE (3 & 6 HOUR STORMS)=0.3486 Developed Condition: Low Loss = 0.9 - (0.8 * %impervious) LOW LOSS RATE =0.8500 Basin Site: Low Loss = 10% Where:For 100 Year Storm - Low Loss should be between 80% & 90% T=Time in minutes. To get an average value for each unit time period, Use T=1/2 the unit time for the first time period,of the Rainfall Rate T=1 1/2 unit time for the second period, etc. (24-(T/60))^1.55 + LAND USE SF - DETACHED LANDSCAPING PAVING/HARDSCAPE AVERAGE ADJUSTED LOSS RATE RCFC & WCD HYDROLOGY MANUAL SYNTHETIC UNIT HYDROGRAPH METHOD BASIC DATA CALCULATION FORM Del Webb Explore at Palm Desert RJB 2636 AMC II Plate E-2.1 Page 3 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 4.66 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 3.09 Maxwell Drywells UNIT TIME-PERCENT OF LAG 161.7 Number 0 TOTAL ADJUSTED STORM RAIN-INCHES 1.57 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE-in/hr 0.35 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 5 0.08 3.6 0.68 0.35 0.58 0.33 1.55 465 465 4,018 140 140 326 0.01 294.58 2 10 0.17 4.2 0.79 0.35 0.67 0.44 2.08 625 950 4,225 147 147 803 0.02 294.69 3 15 0.25 4.4 0.83 0.35 0.70 0.48 2.26 678 1,481 4,451 155 155 1,327 0.03 294.81 4 20 0.33 4.6 0.87 0.35 0.74 0.52 2.44 731 2,057 4,697 163 163 1,894 0.04 294.94 5 25 0.42 5.0 0.94 0.35 0.80 0.59 2.79 837 2,732 4,920 171 171 2,561 0.06 295.08 6 30 0.50 5.6 1.06 0.35 0.90 0.71 3.32 997 3,557 5,183 180 180 3,377 0.08 295.22 7 35 0.58 6.4 1.21 0.35 1.02 0.86 4.03 1,209 4,587 5,511 191 191 4,395 0.10 295.40 8 40 0.67 8.1 1.53 0.35 1.30 1.18 5.54 1,661 6,057 5,979 208 208 5,849 0.13 295.66 9 45 0.75 13.1 2.47 0.35 2.10 2.12 9.97 2,990 8,839 6,774 235 235 8,604 0.20 296.12 10 50 0.83 34.5 6.50 0.35 5.52 6.15 28.93 8,679 17,282 8,690 302 302 16,981 0.39 297.21 11 55 0.92 6.7 1.26 0.35 1.07 0.91 4.30 1,289 18,270 8,890 309 309 17,961 0.41 297.31 12 60 1.00 3.8 0.72 0.35 0.61 0.37 1.73 518 18,479 8,933 310 310 18,169 0.42 297.34 TOTAL RAINFALL 1.57 in RAINFALL VOLUME 26,581 cu-ft SOIL LOSSES 5,902 cu-ft EFFECTIVE RAIN 1.22 in FLOOD VOLUME 0.47 acft FLOOD VOLUME 20,679 cu-ft REQUIRED STORAGE 0.42 REQUIRED STORAGE 18,169 cu-ft MAX WSEL 297.34 ft PEAK FLOW RATE 28.93 cfs TOTAL BASIN LOSSES 2,509 cu-ft AVERAGE PERCOLATION RATE 41.82 cf/min EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Total In Basin in/hr Time Loss Rate Basin Losses Del Webb Explore at Palm DesertRCFC & WCD HYDROLOGY MANUAL SYNTHETIC UNIT HYDROGRAPH METHOD SHORTCUT METHOD 1-HOUR STORM Plate E-2.2 1-Hour Storm Page 4 of 13 PROJECT: Job No.:2636 BY:RJB DATE DRAINAGE AREA-ACRES 4.66 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 3.09 Maxwell Drywells UNIT TIME-PERCENT OF LAG 161.7 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.27 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.35 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 5 0.08 1.3 0.35 0.35 0.30 0.01 0.03 8 8 3,823 133 8 0 0.00 294.50 2 10 0.17 1.3 0.35 0.35 0.30 0.01 0.03 8 8 3,823 133 8 0 0.00 294.50 3 15 0.25 1.1 0.30 0.35 0.25 0.04 0.21 63 63 3,846 134 63 0 0.00 294.50 4 20 0.33 1.5 0.41 0.35 0.35 0.06 0.28 85 85 3,856 134 85 0 0.00 294.50 5 25 0.42 1.5 0.41 0.35 0.35 0.06 0.28 85 85 3,856 134 85 0 0.00 294.50 6 30 0.50 1.8 0.49 0.35 0.42 0.14 0.67 200 200 3,905 136 136 64 0.00 294.52 7 35 0.58 1.5 0.41 0.35 0.35 0.06 0.28 85 149 3,883 135 135 14 0.00 294.50 8 40 0.67 1.8 0.49 0.35 0.42 0.14 0.67 200 214 3,911 136 136 78 0.00 294.52 9 45 0.75 1.8 0.49 0.35 0.42 0.14 0.67 200 278 3,938 137 137 141 0.00 294.53 10 50 0.83 1.5 0.41 0.35 0.35 0.06 0.28 85 226 3,916 136 136 90 0.00 294.52 11 55 0.92 1.6 0.44 0.35 0.37 0.09 0.41 123 213 3,910 136 136 77 0.00 294.52 12 60 1.00 1.8 0.49 0.35 0.42 0.14 0.67 200 277 3,938 137 137 141 0.00 294.53 13 65 1.08 2.2 0.60 0.35 0.51 0.25 1.18 354 494 4,030 140 140 354 0.01 294.58 14 70 1.17 2.2 0.60 0.35 0.51 0.25 1.18 354 708 4,122 143 143 565 0.01 294.63 15 75 1.25 2.2 0.60 0.35 0.51 0.25 1.18 354 919 4,211 146 146 772 0.02 294.68 16 80 1.33 2.0 0.54 0.35 0.46 0.20 0.92 277 1,049 4,267 148 148 901 0.02 294.71 17 85 1.42 2.6 0.71 0.35 0.60 0.36 1.69 507 1,408 4,420 153 153 1,255 0.03 294.79 18 90 1.50 2.7 0.74 0.35 0.63 0.39 1.82 546 1,801 4,588 159 159 1,641 0.04 294.88 19 95 1.58 2.4 0.65 0.35 0.56 0.31 1.44 431 2,072 4,704 163 163 1,909 0.04 294.95 20 100 1.67 2.7 0.74 0.35 0.63 0.39 1.82 546 2,454 4,832 168 168 2,287 0.05 295.03 21 105 1.75 3.3 0.90 0.35 0.76 0.55 2.59 776 3,063 5,026 175 175 2,889 0.07 295.13 22 110 1.83 3.1 0.84 0.35 0.72 0.50 2.33 700 3,588 5,193 180 180 3,408 0.08 295.23 23 115 1.92 2.9 0.79 0.35 0.67 0.44 2.08 623 4,030 5,334 185 185 3,845 0.09 295.31 24 120 2.00 3.0 0.82 0.35 0.69 0.47 2.20 661 4,506 5,486 190 190 4,316 0.10 295.39 25 125 2.08 3.1 0.84 0.35 0.72 0.50 2.33 700 5,015 5,648 196 196 4,819 0.11 295.48 RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 3-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Loss Rate Basin Losses Plate E-2.2 3-Hour Storm Page 5 of 13 PROJECT: Job No.:2636 BY:RJB DATE DRAINAGE AREA-ACRES 4.66 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 3.09 Maxwell Drywells UNIT TIME-PERCENT OF LAG 161.7 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.27 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.35 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 3-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Loss Rate Basin Losses 26 130 2.17 4.2 1.14 0.35 0.97 0.80 3.74 1,122 5,942 5,943 206 206 5,735 0.13 295.64 27 135 2.25 5.0 1.36 0.35 1.16 1.01 4.77 1,430 7,165 6,333 220 220 6,945 0.16 295.86 28 140 2.33 3.5 0.95 0.35 0.81 0.60 2.84 853 7,798 6,529 227 227 7,572 0.17 295.97 29 145 2.42 6.8 1.85 0.35 1.57 1.50 7.07 2,122 9,693 6,975 242 242 9,451 0.22 296.23 30 150 2.50 7.3 1.99 0.35 1.69 1.64 7.71 2,314 11,765 7,462 259 259 11,506 0.26 296.51 31 155 2.58 8.2 2.23 0.35 1.90 1.89 8.87 2,660 14,165 8,027 279 279 13,887 0.32 296.84 32 160 2.67 5.9 1.61 0.35 1.37 1.26 5.92 1,776 15,662 8,361 290 290 15,372 0.35 297.03 33 165 2.75 2.0 0.54 0.35 0.46 0.20 0.92 277 15,649 8,358 290 290 15,358 0.35 297.03 34 170 2.83 1.8 0.49 0.35 0.42 0.14 0.67 200 15,558 8,340 290 290 15,269 0.35 297.02 35 175 2.92 1.8 0.49 0.35 0.42 0.14 0.67 200 15,469 8,322 289 289 15,180 0.35 297.01 36 180 3.00 0.6 0.16 0.35 0.14 0.02 0.12 35 15,214 8,270 287 287 14,927 0.34 296.98 TOTAL RAIN RAINFALL VOLUME SOIL LOSSES EFFECTIVE RAIN FLOOD VOLUME FLOOD VOLUME REQUIRED STORAGE REQUIRED STORAGE MAX WSEL PEAK FLOW RATE TOTAL BASIN LOSSES AVERAGE PERCOLATION RATE EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY 6,227 cu-ft 34.59 cf/min 1.25 in 0.49 acft 21,154 cu-ft 0.35 acft 15,372 cu-ft 17,278 cu-ft 2.27 in 38,432 cu-ft 297.03 ft 8.87 cfs Plate E-2.2 3-Hour Storm Page 6 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 4.66 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 3.09 Maxwell Drywells UNIT TIME-PERCENT OF LAG 161.7 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.98 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.35 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 5 0.08 0.5 0.18 0.35 0.15 0.03 0.13 38 38 3,836 133 38 0 0.00 294.50 2 10 0.17 0.6 0.21 0.35 0.18 0.03 0.15 45 45 3,839 133 45 0 0.00 294.50 3 15 0.25 0.6 0.21 0.35 0.18 0.03 0.15 45 45 3,839 133 45 0 0.00 294.50 4 20 0.33 0.6 0.21 0.35 0.18 0.03 0.15 45 45 3,839 133 45 0 0.00 294.50 5 25 0.42 0.6 0.21 0.35 0.18 0.03 0.15 45 45 3,839 133 45 0 0.00 294.50 6 30 0.50 0.7 0.25 0.35 0.21 0.04 0.18 53 53 3,842 133 53 0 0.00 294.50 7 35 0.58 0.7 0.25 0.35 0.21 0.04 0.18 53 53 3,842 133 53 0 0.00 294.50 8 40 0.67 0.7 0.25 0.35 0.21 0.04 0.18 53 53 3,842 133 53 0 0.00 294.50 9 45 0.75 0.7 0.25 0.35 0.21 0.04 0.18 53 53 3,842 133 53 0 0.00 294.50 10 50 0.83 0.7 0.25 0.35 0.21 0.04 0.18 53 53 3,842 133 53 0 0.00 294.50 11 55 0.92 0.7 0.25 0.35 0.21 0.04 0.18 53 53 3,842 133 53 0 0.00 294.50 12 60 1.00 0.8 0.29 0.35 0.24 0.04 0.20 61 61 3,845 134 61 0 0.00 294.50 13 65 1.08 0.8 0.29 0.35 0.24 0.04 0.20 61 61 3,845 134 61 0 0.00 294.50 14 70 1.17 0.8 0.29 0.35 0.24 0.04 0.20 61 61 3,845 134 61 0 0.00 294.50 15 75 1.25 0.8 0.29 0.35 0.24 0.04 0.20 61 61 3,845 134 61 0 0.00 294.50 16 80 1.33 0.8 0.29 0.35 0.24 0.04 0.20 61 61 3,845 134 61 0 0.00 294.50 17 85 1.42 0.8 0.29 0.35 0.24 0.04 0.20 61 61 3,845 134 61 0 0.00 294.50 18 90 1.50 0.8 0.29 0.35 0.24 0.04 0.20 61 61 3,845 134 61 0 0.00 294.50 19 95 1.58 0.8 0.29 0.35 0.24 0.04 0.20 61 61 3,845 134 61 0 0.00 294.50 20 100 1.67 0.8 0.29 0.35 0.24 0.04 0.20 61 61 3,845 134 61 0 0.00 294.50 21 105 1.75 0.8 0.29 0.35 0.24 0.04 0.20 61 61 3,845 134 61 0 0.00 294.50 22 110 1.83 0.8 0.29 0.35 0.24 0.04 0.20 61 61 3,845 134 61 0 0.00 294.50 23 115 1.92 0.8 0.29 0.35 0.24 0.04 0.20 61 61 3,845 134 61 0 0.00 294.50 24 120 2.00 0.9 0.32 0.35 0.27 0.05 0.23 68 68 3,848 134 68 0 0.00 294.50 Loss Rate RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 6-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Basin Losses Plate E-2.2 6-Hour Storm Page 7 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 4.66 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 3.09 Maxwell Drywells UNIT TIME-PERCENT OF LAG 161.7 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.98 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.35 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft Loss Rate RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 6-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Basin Losses 25 125 2.08 0.8 0.29 0.35 0.24 0.04 0.20 61 61 3,845 134 61 0 0.00 294.50 26 130 2.17 0.9 0.32 0.35 0.27 0.05 0.23 68 68 3,848 134 68 0 0.00 294.50 27 135 2.25 0.9 0.32 0.35 0.27 0.05 0.23 68 68 3,848 134 68 0 0.00 294.50 28 140 2.33 0.9 0.32 0.35 0.27 0.05 0.23 68 68 3,848 134 68 0 0.00 294.50 29 145 2.42 0.9 0.32 0.35 0.27 0.05 0.23 68 68 3,848 134 68 0 0.00 294.50 30 150 2.50 0.9 0.32 0.35 0.27 0.05 0.23 68 68 3,848 134 68 0 0.00 294.50 31 155 2.58 0.9 0.32 0.35 0.27 0.05 0.23 68 68 3,848 134 68 0 0.00 294.50 32 160 2.67 0.9 0.32 0.35 0.27 0.05 0.23 68 68 3,848 134 68 0 0.00 294.50 33 165 2.75 1.0 0.36 0.35 0.30 0.01 0.04 13 13 3,825 133 13 0 0.00 294.50 34 170 2.83 1.0 0.36 0.35 0.30 0.01 0.04 13 13 3,825 133 13 0 0.00 294.50 35 175 2.92 1.0 0.36 0.35 0.30 0.01 0.04 13 13 3,825 133 13 0 0.00 294.50 36 180 3.00 1.0 0.36 0.35 0.30 0.01 0.04 13 13 3,825 133 13 0 0.00 294.50 37 185 3.08 1.0 0.36 0.35 0.30 0.01 0.04 13 13 3,825 133 13 0 0.00 294.50 38 190 3.17 1.1 0.39 0.35 0.33 0.04 0.21 63 63 3,846 134 63 0 0.00 294.50 39 195 3.25 1.1 0.39 0.35 0.33 0.04 0.21 63 63 3,846 134 63 0 0.00 294.50 40 200 3.33 1.1 0.39 0.35 0.33 0.04 0.21 63 63 3,846 134 63 0 0.00 294.50 41 205 3.42 1.2 0.43 0.35 0.36 0.08 0.38 114 114 3,868 134 114 0 0.00 294.50 42 210 3.50 1.3 0.46 0.35 0.40 0.12 0.55 164 164 3,889 135 135 29 0.00 294.51 43 215 3.58 1.4 0.50 0.35 0.43 0.15 0.71 214 243 3,923 136 136 107 0.00 294.53 44 220 3.67 1.4 0.50 0.35 0.43 0.15 0.71 214 322 3,957 137 137 184 0.00 294.54 45 225 3.75 1.5 0.54 0.35 0.46 0.19 0.88 265 449 4,011 139 139 310 0.01 294.57 46 230 3.83 1.5 0.54 0.35 0.46 0.19 0.88 265 575 4,065 141 141 434 0.01 294.60 47 235 3.92 1.6 0.57 0.35 0.49 0.22 1.05 315 749 4,139 144 144 606 0.01 294.64 48 240 4.00 1.6 0.57 0.35 0.49 0.22 1.05 315 921 4,212 146 146 775 0.02 294.68 49 245 4.08 1.7 0.61 0.35 0.52 0.26 1.22 366 1,141 4,306 150 150 991 0.02 294.73 50 250 4.17 1.8 0.64 0.35 0.55 0.30 1.39 416 1,407 4,420 153 153 1,254 0.03 294.79 Plate E-2.2 6-Hour Storm Page 8 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 4.66 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 3.09 Maxwell Drywells UNIT TIME-PERCENT OF LAG 161.7 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.98 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.35 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft Loss Rate RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 6-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Basin Losses 51 255 4.25 1.9 0.68 0.35 0.58 0.33 1.56 467 1,721 4,554 158 158 1,562 0.04 294.87 52 260 4.33 2.0 0.72 0.35 0.61 0.37 1.72 517 2,080 4,707 163 163 1,916 0.04 294.95 53 265 4.42 2.1 0.75 0.35 0.64 0.40 1.89 568 2,484 4,841 168 168 2,316 0.05 295.03 54 270 4.50 2.1 0.75 0.35 0.64 0.40 1.89 568 2,883 4,969 173 173 2,711 0.06 295.10 55 275 4.58 2.2 0.79 0.35 0.67 0.44 2.06 618 3,329 5,111 177 177 3,152 0.07 295.18 56 280 4.67 2.3 0.82 0.35 0.70 0.47 2.23 669 3,820 5,267 183 183 3,637 0.08 295.27 57 285 4.75 2.4 0.86 0.35 0.73 0.51 2.40 719 4,356 5,438 189 189 4,167 0.10 295.36 58 290 4.83 2.4 0.86 0.35 0.73 0.51 2.40 719 4,886 5,607 195 195 4,692 0.11 295.46 59 295 4.92 2.5 0.89 0.35 0.76 0.55 2.56 769 5,461 5,790 201 201 5,260 0.12 295.56 60 300 5.00 2.6 0.93 0.35 0.79 0.58 2.73 820 6,080 5,987 208 208 5,872 0.13 295.67 61 305 5.08 3.1 1.11 0.35 0.94 0.76 3.57 1,072 6,944 6,262 217 217 6,727 0.15 295.82 62 310 5.17 3.6 1.29 0.35 1.09 0.94 4.41 1,324 8,051 6,588 229 229 7,823 0.18 296.01 63 315 5.25 3.9 1.39 0.35 1.19 1.05 4.92 1,476 9,299 6,882 239 239 9,060 0.21 296.18 64 320 5.33 4.2 1.50 0.35 1.28 1.15 5.42 1,627 10,687 7,209 250 250 10,436 0.24 296.37 65 325 5.42 4.7 1.68 0.35 1.43 1.33 6.26 1,879 12,316 7,592 264 264 12,052 0.28 296.59 66 330 5.50 5.6 2.00 0.35 1.70 1.65 7.78 2,333 14,386 8,079 281 281 14,105 0.32 296.87 67 335 5.58 1.9 0.68 0.35 0.58 0.33 1.56 467 14,572 8,123 282 282 14,290 0.33 296.89 68 340 5.67 0.9 0.32 0.35 0.27 0.05 0.23 68 14,358 8,073 280 280 14,078 0.32 296.86 69 345 5.75 0.6 0.21 0.35 0.18 0.03 0.15 45 14,123 8,017 278 278 13,845 0.32 296.83 70 350 5.83 0.5 0.18 0.35 0.15 0.03 0.13 38 13,883 7,961 276 276 13,606 0.31 296.80 71 355 5.92 0.3 0.11 0.35 0.09 0.02 0.08 23 13,629 7,901 274 274 13,355 0.31 296.76 72 360 6.00 0.2 0.07 0.35 0.06 0.01 0.05 15 13,370 7,840 272 272 13,097 0.30 296.73 TOTAL RAINFALL RAINFALL VOLUME SOIL LOSSES EFFECTIVE RAIN FLOOD VOLUME FLOOD VOLUME REQUIRED STORAGE REQUIRED STORAGE MAX WSEL PEAK FLOW RATE TOTAL BASIN LOSSES AVERAGE PERCOLATION RATE EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY 23.54 cf/min 8,476 cu-ft 1.27 in 0.50 acft 21,573 cu-ft 0.33 acft 14,290 cu-ft 50,453 cu-ft 2.98 in 28,879 cu-ft 296.89 ft 7.78 cfs Plate E-2.2 6-Hour Storm Page 9 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 4.66 VARIABLE LOSS RATE (AVG) IN/HR Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 15 Fm = Minimum value on loss curve (in/hr)0.17 LAG TIME - MINUTES 3.09 C 0.00323 Maxwell Drywells UNIT TIME-PERCENT OF LAG 485%Low Loss Rate (percent)85.00%Number 0 TOTAL ADJUSTED STORM RAIN (in)4.59 Drywell Percolation Rate 0.00 cfs 0.00 cfm Unit Time Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 15 0.25 0.2 0.037 0.616 0.031 0.01 0.03 23 23 3,829 399 23 0 0.00 294.50 2 30 0.50 0.3 0.055 0.608 0.047 0.01 0.04 35 35 3,834 399 35 0 0.00 294.50 3 45 0.75 0.3 0.055 0.601 0.047 0.01 0.04 35 35 3,834 399 35 0 0.00 294.50 4 60 1.00 0.4 0.073 0.594 0.062 0.01 0.05 47 47 3,839 400 47 0 0.00 294.50 5 75 1.25 0.3 0.055 0.587 0.047 0.01 0.04 35 35 3,834 399 35 0 0.00 294.50 6 90 1.50 0.3 0.055 0.580 0.047 0.01 0.04 35 35 3,834 399 35 0 0.00 294.50 7 105 1.75 0.3 0.055 0.573 0.047 0.01 0.04 35 35 3,834 399 35 0 0.00 294.50 8 120 2.00 0.4 0.073 0.566 0.062 0.01 0.05 47 47 3,839 400 47 0 0.00 294.50 9 135 2.25 0.4 0.073 0.560 0.062 0.01 0.05 47 47 3,839 400 47 0 0.00 294.50 10 150 2.50 0.4 0.073 0.553 0.062 0.01 0.05 47 47 3,839 400 47 0 0.00 294.50 11 165 2.75 0.5 0.092 0.546 0.078 0.01 0.06 58 58 3,844 400 58 0 0.00 294.50 12 180 3.00 0.5 0.092 0.539 0.078 0.01 0.06 58 58 3,844 400 58 0 0.00 294.50 13 195 3.25 0.5 0.092 0.533 0.078 0.01 0.06 58 58 3,844 400 58 0 0.00 294.50 14 210 3.50 0.5 0.092 0.526 0.078 0.01 0.06 58 58 3,844 400 58 0 0.00 294.50 15 225 3.75 0.5 0.092 0.519 0.078 0.01 0.06 58 58 3,844 400 58 0 0.00 294.50 16 240 4.00 0.6 0.110 0.513 0.094 0.02 0.08 70 70 3,849 401 70 0 0.00 294.50 17 255 4.25 0.6 0.110 0.506 0.094 0.02 0.08 70 70 3,849 401 70 0 0.00 294.50 18 270 4.50 0.7 0.129 0.500 0.109 0.02 0.09 82 82 3,854 401 82 0 0.00 294.50 19 285 4.75 0.7 0.129 0.494 0.109 0.02 0.09 82 82 3,854 401 82 0 0.00 294.50 20 300 5.00 0.8 0.147 0.487 0.125 0.02 0.10 93 93 3,859 402 93 0 0.00 294.50 21 315 5.25 0.6 0.110 0.481 0.094 0.02 0.08 70 70 3,849 401 70 0 0.00 294.50 22 330 5.50 0.7 0.129 0.475 0.109 0.02 0.09 82 82 3,854 401 82 0 0.00 294.50 23 345 5.75 0.8 0.147 0.468 0.125 0.02 0.10 93 93 3,859 402 93 0 0.00 294.50 24 360 6.00 0.8 0.147 0.462 0.125 0.02 0.10 93 93 3,859 402 93 0 0.00 294.50 25 375 6.25 0.9 0.165 0.456 0.140 0.02 0.12 105 105 3,864 403 105 0 0.00 294.50 26 390 6.50 0.9 0.165 0.450 0.140 0.02 0.12 105 105 3,864 403 105 0 0.00 294.50 27 405 6.75 1.0 0.184 0.444 0.156 0.03 0.13 117 117 3,869 403 117 0 0.00 294.50 28 420 7.00 1.0 0.184 0.438 0.156 0.03 0.13 117 117 3,869 403 117 0 0.00 294.50 29 435 7.25 1.0 0.184 0.432 0.156 0.03 0.13 117 117 3,869 403 117 0 0.00 294.50 30 450 7.50 1.1 0.202 0.426 0.172 0.03 0.14 128 128 3,874 404 128 0 0.00 294.50 31 465 7.75 1.2 0.220 0.420 0.187 0.03 0.16 140 140 3,879 404 140 0 0.00 294.50 32 480 8.00 1.3 0.239 0.414 0.203 0.04 0.17 152 152 3,884 405 152 0 0.00 294.50 33 495 8.25 1.5 0.275 0.409 0.234 0.04 0.19 175 175 3,894 406 175 0 0.00 294.50 34 510 8.50 1.5 0.275 0.403 0.234 0.04 0.19 175 175 3,894 406 175 0 0.00 294.50 35 525 8.75 1.6 0.294 0.397 0.250 0.04 0.21 187 187 3,899 406 187 0 0.00 294.50 36 540 9.00 1.7 0.312 0.392 0.265 0.05 0.22 198 198 3,904 407 198 0 0.00 294.50 37 555 9.25 1.9 0.349 0.386 0.297 0.05 0.25 221 221 3,914 408 221 0 0.00 294.50 38 570 9.50 2.0 0.367 0.381 0.312 0.06 0.26 233 233 3,919 408 233 0 0.00 294.50 39 585 9.75 2.1 0.386 0.375 0.328 0.01 0.05 43 43 3,838 400 43 0 0.00 294.50 40 600 10.00 2.2 0.404 0.370 0.343 0.03 0.16 144 144 3,881 404 144 0 0.00 294.50 41 615 10.25 1.5 0.275 0.365 0.234 0.04 0.19 175 175 3,894 406 175 0 0.00 294.50 42 630 10.50 1.5 0.275 0.359 0.234 0.04 0.19 175 175 3,894 406 175 0 0.00 294.50 43 645 10.75 2.0 0.367 0.354 0.312 0.01 0.06 56 56 3,843 400 56 0 0.00 294.50 in/hr Total In Basin UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Loss Rate Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD MANUAL 24-HOUR STORM Basin Losses Plate E-2.2 24-Hour Storm Page 10 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 4.66 VARIABLE LOSS RATE (AVG) IN/HR Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 15 Fm = Minimum value on loss curve (in/hr)0.17 LAG TIME - MINUTES 3.09 C 0.00323 Maxwell Drywells UNIT TIME-PERCENT OF LAG 485%Low Loss Rate (percent)85.00%Number 0 TOTAL ADJUSTED STORM RAIN (in)4.59 Drywell Percolation Rate 0.00 cfs 0.00 cfm Unit Time Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft in/hr Total In Basin UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Loss Rate Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD MANUAL 24-HOUR STORM Basin Losses 44 660 11.00 2.0 0.367 0.349 0.312 0.02 0.09 78 78 3,852 401 78 0 0.00 294.50 45 675 11.25 1.9 0.349 0.344 0.297 0.01 0.02 22 22 3,829 399 22 0 0.00 294.50 46 690 11.50 1.9 0.349 0.339 0.297 0.01 0.05 43 43 3,838 400 43 0 0.00 294.50 47 705 11.75 1.7 0.312 0.334 0.265 0.05 0.22 198 198 3,904 407 198 0 0.00 294.50 48 720 12.00 1.8 0.330 0.329 0.281 0.00 0.01 8 8 3,823 398 8 0 0.00 294.50 49 735 12.25 2.5 0.459 0.324 0.390 0.14 0.64 572 572 4,064 423 423 149 0.00 294.53 50 750 12.50 2.6 0.477 0.319 0.406 0.16 0.75 671 820 4,169 434 434 385 0.01 294.59 51 765 12.75 2.8 0.514 0.314 0.437 0.20 0.94 846 1,231 4,345 453 453 779 0.02 294.68 52 780 13.00 2.9 0.532 0.309 0.453 0.22 1.05 944 1,723 4,555 474 474 1,248 0.03 294.79 53 795 13.25 3.4 0.624 0.305 0.531 0.32 1.50 1,352 2,601 4,879 508 508 2,093 0.05 294.99 54 810 13.50 3.4 0.624 0.300 0.531 0.32 1.52 1,372 3,464 5,154 537 537 2,928 0.07 295.14 55 825 13.75 2.3 0.422 0.296 0.359 0.13 0.60 536 3,464 5,154 537 537 2,927 0.07 295.14 56 840 14.00 2.3 0.422 0.291 0.359 0.13 0.62 555 3,482 5,160 537 537 2,945 0.07 295.15 57 855 14.25 2.7 0.496 0.287 0.421 0.21 0.98 885 3,830 5,270 549 549 3,281 0.08 295.21 58 870 14.50 2.6 0.477 0.282 0.406 0.20 0.92 826 4,107 5,358 558 558 3,549 0.08 295.25 59 885 14.75 2.6 0.477 0.278 0.406 0.20 0.94 844 4,393 5,450 568 568 3,825 0.09 295.30 60 900 15.00 2.5 0.459 0.274 0.390 0.19 0.87 784 4,610 5,519 575 575 4,035 0.09 295.34 61 915 15.25 2.4 0.441 0.269 0.375 0.17 0.80 724 4,759 5,566 580 580 4,179 0.10 295.37 62 930 15.50 2.3 0.422 0.265 0.359 0.16 0.74 664 4,843 5,593 583 583 4,261 0.10 295.38 63 945 15.75 1.9 0.349 0.261 0.297 0.09 0.41 370 4,631 5,525 576 576 4,056 0.09 295.34 64 960 16.00 1.9 0.349 0.257 0.297 0.09 0.43 387 4,443 5,466 569 569 3,874 0.09 295.31 65 975 16.25 0.4 0.073 0.253 0.062 0.01 0.05 47 3,920 5,299 552 552 3,368 0.08 295.22 66 990 16.50 0.4 0.073 0.250 0.062 0.01 0.05 47 3,415 5,138 535 535 2,880 0.07 295.13 67 1005 16.75 0.3 0.055 0.246 0.047 0.01 0.04 35 2,915 4,979 519 519 2,396 0.06 295.05 68 1020 17.00 0.3 0.055 0.242 0.047 0.01 0.04 35 2,431 4,825 503 503 1,929 0.04 294.95 69 1035 17.25 0.5 0.092 0.238 0.078 0.01 0.06 58 1,987 4,667 486 486 1,501 0.03 294.85 70 1050 17.50 0.5 0.092 0.235 0.078 0.01 0.06 58 1,559 4,485 467 467 1,092 0.03 294.76 71 1065 17.75 0.5 0.092 0.231 0.078 0.01 0.06 58 1,150 4,310 449 449 701 0.02 294.66 72 1080 18.00 0.4 0.073 0.228 0.062 0.01 0.05 47 748 4,139 431 431 317 0.01 294.57 73 1095 18.25 0.4 0.073 0.225 0.062 0.01 0.05 47 363 3,974 414 363 0 0.00 294.50 74 1110 18.50 0.4 0.073 0.221 0.062 0.01 0.05 47 47 3,839 400 47 0 0.00 294.50 75 1125 18.75 0.3 0.055 0.218 0.047 0.01 0.04 35 35 3,834 399 35 0 0.00 294.50 76 1140 19.00 0.2 0.037 0.215 0.031 0.01 0.03 23 23 3,829 399 23 0 0.00 294.50 77 1155 19.25 0.3 0.055 0.212 0.047 0.01 0.04 35 35 3,834 399 35 0 0.00 294.50 78 1170 19.50 0.4 0.073 0.209 0.062 0.01 0.05 47 47 3,839 400 47 0 0.00 294.50 79 1185 19.75 0.3 0.055 0.206 0.047 0.01 0.04 35 35 3,834 399 35 0 0.00 294.50 80 1200 20.00 0.2 0.037 0.203 0.031 0.01 0.03 23 23 3,829 399 23 0 0.00 294.50 81 1215 20.25 0.3 0.055 0.201 0.047 0.01 0.04 35 35 3,834 399 35 0 0.00 294.50 82 1230 20.50 0.3 0.055 0.198 0.047 0.01 0.04 35 35 3,834 399 35 0 0.00 294.50 83 1245 20.75 0.3 0.055 0.196 0.047 0.01 0.04 35 35 3,834 399 35 0 0.00 294.50 84 1260 21.00 0.2 0.037 0.193 0.031 0.01 0.03 23 23 3,829 399 23 0 0.00 294.50 85 1275 21.25 0.3 0.055 0.191 0.047 0.01 0.04 35 35 3,834 399 35 0 0.00 294.50 86 1290 21.50 0.2 0.037 0.189 0.031 0.01 0.03 23 23 3,829 399 23 0 0.00 294.50 Plate E-2.2 24-Hour Storm Page 11 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 4.66 VARIABLE LOSS RATE (AVG) IN/HR Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 15 Fm = Minimum value on loss curve (in/hr)0.17 LAG TIME - MINUTES 3.09 C 0.00323 Maxwell Drywells UNIT TIME-PERCENT OF LAG 485%Low Loss Rate (percent)85.00%Number 0 TOTAL ADJUSTED STORM RAIN (in)4.59 Drywell Percolation Rate 0.00 cfs 0.00 cfm Unit Time Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft in/hr Total In Basin UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Loss Rate Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD MANUAL 24-HOUR STORM Basin Losses 87 1305 21.75 0.3 0.055 0.187 0.047 0.01 0.04 35 35 3,834 399 35 0 0.00 294.50 88 1320 22.00 0.2 0.037 0.185 0.031 0.01 0.03 23 23 3,829 399 23 0 0.00 294.50 89 1335 22.25 0.3 0.055 0.183 0.047 0.01 0.04 35 35 3,834 399 35 0 0.00 294.50 90 1350 22.50 0.2 0.037 0.181 0.031 0.01 0.03 23 23 3,829 399 23 0 0.00 294.50 91 1365 22.75 0.2 0.037 0.180 0.031 0.01 0.03 23 23 3,829 399 23 0 0.00 294.50 92 1380 23.00 0.2 0.037 0.178 0.031 0.01 0.03 23 23 3,829 399 23 0 0.00 294.50 93 1395 23.25 0.2 0.037 0.177 0.031 0.01 0.03 23 23 3,829 399 23 0 0.00 294.50 94 1410 23.50 0.2 0.037 0.176 0.031 0.01 0.03 23 23 3,829 399 23 0 0.00 294.50 95 1425 23.75 0.2 0.037 0.175 0.031 0.01 0.03 23 23 3,829 399 23 0 0.00 294.50 96 1440 24.00 0.2 0.037 0.174 0.031 0.01 0.03 23 23 3,829 399 23 0 0.00 294.50 EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY TOTAL RAINFALL RAINFALL VOLUME SOIL LOSSES EFFECTIVE RAIN FLOOD VOLUME FLOOD VOLUME REQUIRED STORAGE REQUIRED STORAGE MAX WSEL PEAK FLOW RATE TOTAL BASIN LOSSES AVERAGE PERCOLATION RATE 17,973 cu-ft 12.48 cf/min 1.06 in 0.41 acft 17,973 cu-ft 0.10 acft 4,261 cu-ft 4.59 in 77,710 cu-ft 59,738 cu-ft 295.38 ft 1.52 cfs Plate E-2.2 24-Hour Storm Page 12 of 13 PROECT JOB No. BASIN DESIGNATION: BASIN CHARACTERISTICS CONTOUR ELEVATION INCR TOTAL INCR TOTAL INCR (ft)(ft)(sf)(sf)(cuft)(cuft)(acre-ft) 294.5 0 0 3,819 0 0 0.00 295 0.5 0.5 910 4,730 2,133 2,133 0.05 296 1 1.5 1,783 6,513 5,598 7,731 0.18 297 1 2.5 1,733 8,246 7,362 15,093 0.35 298 1 3.5 1,859 10,104 9,159 24,252 0.56 299 1 4.5 1,771 11,876 10,978 35,230 0.81 WHERE: TOTAL Retention Basin-B BASIN VOLUME WORKSHEET DEPTH AREA VOLUME Del Webb Explore at Palm Desert 2636 ()()2121213 1 AAAAEEV++−= Basin Volume Worksheet Page 13 of 13 RJB 2 AMC II AREA SOIL TRIBUTARY AREAS ACRES LOW LOSS RI INFILTRATION IMPERVIOUS DESIG GROUP CONDITION NUMBER RATE PERCENT 4 A SF - DETACHED 2.624 D 32 0.74 0.50 9 A LANDSCAPING 0.364 D 32 0.74 0.10 2 A PAVING/HARDSCAPE 1.027 D 32 0.74 1.00 800 ft 400 ft 303.9 ft ELEVATION OF CONCENTRATION POINT 298.5 ft 0.02 100 LOW LOSS RATE (Storm Events > 10 Years)85% POINT RAIN FROM NOAA ATLAS 14 1-HOUR 1.57 in 3-HOUR 2.27 in 6-HOUR 2.98 in 24-HOUR 4.59 in BASIN CHARACTERISTICS:ELEVATION AREA 294.5 ft 2,426 sf 295.0 ft 3,545 sf 296.0 ft 5,027 sf 297.0 ft 6,683 sf 298.0 ft 8,157 sf 299.0 ft 9,646 sf PERCOLATION RATE (in/hr)5.0 in/hr DRYWELL DATA NUMBER USED PERCOLATION RATE LOWEST FLOWLINE ELEVATION 298.54 LOWEST PAD ELEVATION 300.6 PROJECT NUMBER CONCENTRATION POINT DESIGNATION 2636 Retention Basin AMC NUMBER RCFCD SYNTHETIC UNIT HYDROGRAPH - SHORTCUT METHOD DATA INPUT SHEET WORKSHEET PREPARED BY: PROJECT NAME DATE January 9, 2024 Del Webb Explore at Palm Desert LENGTH OF WATERCOURSE (L) AREA DESIGNATION ELEVATION OF HEADWATER AVERAGE MANNINGS 'N' VALUE STORM FREQUENCY (YEAR) LENGTH TO POINT OPPOSITE CENTROID (Lca) Low Loss Conditions: X=Existing; D=Developed; BS=Retention DA-C MASS GRADING Data Input Sheet Page 1 of 13 PROJECT: Job No.: BY:DATE:1/9/24 [1] AMC II [2] FREQUENCY-YEARS 100 FROM NOAA ATLAS 14 [3] STORM DURATION:Point Rain 1-HOUR 1.57 in 3-HOUR 2.27 in 6-HOUR 2.98 in 24-HOUR 4.59 in STORM DURATION 1-HOUR 3-HOUR 6-HOUR 24-HOUR RAINFALL VOLUME (cu-ft)22,878 33,078 43,424 66,885 SOIL LOSSES (cu-ft)5,041 14,761 24,743 51,219 EFFECTIVE RAIN (in)1.22 1.26 1.28 1.08 FLOOD VOLUME (cu-ft)17,837 18,317 18,681 15,667 (acre-ft)0.41 0.42 0.43 0.36 REQUIRED STORAGE (cu-ft)15,812 13,666 12,695 4,213 (acre-ft)0.36 0.31 0.29 0.10 FACTOR OF SAFETY 1.76 2.04 2.20 6.62 STORAGE PROVIDED (cu-ft) (acre-ft) PEAK FLOW (cfs)n/a 7.64 6.71 1.32 MAXIMUM WSEL (ft)297.57 297.28 297.15 295.64 DEPTH (ft)3.07 2.78 2.65 1.14 DIFFERENCE (ft)0.97 1.26 1.39 2.90 DIFFERENCE (ft)3.03 3.32 3.45 4.96 ESTIMATED TIME TO DEWATER BASIN Based on Total Flood Volume & Average Percolation Rate (days)0.4 0.5 0.7 1.0 Retention Basin DA-C MASS GRADING Del Webb Explore at Palm Desert [10] H-FEET [9] ELEVATION OF CONCENTRATION POINT 4.014 PHYSICAL DATA [1] CONCENTRATION POINT HYDROLOGY MANUAL BASIC DATA CALCULATION FORM 2636 RJB RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD [2] AREA DESIGNATION [3] AREA - ACRES [4] L-FEET [5] L-MILES 800 0.152 [13] L*LCA/S^0.5 5.97 [11] S-FEET/MILE [6] La-FEET [7] La-MILES [8] ELEVATION OF HEADWATER 0.002 400.00 [12] S^0.5 0.076 35.6 303.9 298.5 5.4 0.02 [17] 100% OF LAG-MINUTES 2.7 2.7 [14] AVERAGE MANNINGS 'N' [15] LAG TIME-HOURS 0.04 [16] LAG TIME-MINUTES [18] 200% OF LAG-MINUTES RAINFALL DATA 5.3 NOTE: PEAK FLOW FOR THE 1-HOUR STORM IS NOT REPRESENTATIVE. PER RCFCD PEAK DISCHARGES FROM THE 3-HOUR STORM SHOULD NORMALLY COMPARE WELL WITH RATIONAL PEAKS. LOWEST PAD ELEVATION LOWEST FLOWLINE ELEVATION STORM EVENT SUMMARY 300.6 298.54 27,883 0.64 Plate E-2.1 Page 2 of 13 PROJECT: Job No.: BY:DATE:1/9/24 MAX LOW LOW MIN SOIL RI PERVIOUS DECIMAL ADJUSTED AREA AREA AVERAGE LOSS LOSS RATE AVERAGE GROUP NUMBER AREA PERCENT INFILTRATION WEIGHTED ADJUSTED CONDITION PER ADJUSTED INFILTRATION OF AREA RATE AVERAGE INFILTRATION RCFC/2322 INFILTRATION RATE IMPERVIOUS RATE RATE (in/hr)(in/hr)(in/hr) [Plate C-1][Plate E-6.1][Plate E-6.2][Plate E-6.3] A 32 0.74 50%0.41 2.624 0.654 0.2660 DEVELOPED 0.5000 0.3268 A 32 0.74 10%0.67 0.364 0.091 0.0610 DEVELOPED 0.8200 0.0743 A 32 0.74 100%0.07 1.027 0.256 0.0189 DEVELOPED 0.1000 0.0256 SUM 4.014 SUM 0.3459 0.4267 VARIABLE LOSS RATE CURVE (24-HOUR STORM ONLY) Fm=0.172973134 NOTE: Low loss rates established per RCFC/2322 (Dated: May-30-95) C=0.00320 For 10 Year Storms or Less Ft=C(24-(T/60))^1.55+Fm =0.00320 0.17 in/hr Undeveloped Condition: Low Loss = 90% CONSTANT LOSS RATE (3 & 6 HOUR STORMS)=0.3459 Developed Condition: Low Loss = 0.9 - (0.8 * %impervious) LOW LOSS RATE =0.8500 Basin Site: Low Loss = 10% Where:For 100 Year Storm - Low Loss should be between 80% & 90% T=Time in minutes. To get an average value for each unit time period, Use T=1/2 the unit time for the first time period,of the Rainfall Rate T=1 1/2 unit time for the second period, etc. AVERAGE ADJUSTED LOSS RATE RCFC & WCD HYDROLOGY MANUAL SYNTHETIC UNIT HYDROGRAPH METHOD BASIC DATA CALCULATION FORM Del Webb Explore at Palm Desert RJB 2636 AMC II (24-(T/60))^1.55 + LAND USE SF - DETACHED LANDSCAPING PAVING/HARDSCAPE Plate E-2.1 Page 3 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 4.01 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 2.67 Maxwell Drywells UNIT TIME-PERCENT OF LAG 186.9 Number 0 TOTAL ADJUSTED STORM RAIN-INCHES 1.57 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE-in/hr 0.35 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 5 0.08 3.6 0.68 0.35 0.58 0.33 1.35 404 404 2,730 95 95 309 0.01 294.60 2 10 0.17 4.2 0.79 0.35 0.67 0.45 1.80 541 850 3,067 106 106 743 0.02 294.75 3 15 0.25 4.4 0.83 0.35 0.70 0.48 1.96 587 1,330 3,429 119 119 1,211 0.03 294.91 4 20 0.33 4.6 0.87 0.35 0.74 0.52 2.11 632 1,843 3,670 127 127 1,715 0.04 295.05 5 25 0.42 5.0 0.94 0.35 0.80 0.60 2.41 724 2,439 3,877 135 135 2,305 0.05 295.19 6 30 0.50 5.6 1.06 0.35 0.90 0.71 2.87 861 3,166 4,130 143 143 3,022 0.07 295.36 7 35 0.58 6.4 1.21 0.35 1.02 0.86 3.48 1,044 4,066 4,442 154 154 3,912 0.09 295.57 8 40 0.67 8.1 1.53 0.35 1.30 1.18 4.78 1,433 5,345 4,887 170 170 5,175 0.12 295.87 9 45 0.75 13.1 2.47 0.35 2.10 2.12 8.59 2,577 7,752 5,595 194 194 7,558 0.17 296.31 10 50 0.83 34.5 6.50 0.35 5.52 6.15 24.91 7,473 15,031 7,369 256 256 14,775 0.34 297.43 11 55 0.92 6.7 1.26 0.35 1.07 0.92 3.71 1,113 15,888 7,540 262 262 15,626 0.36 297.55 12 60 1.00 3.8 0.72 0.35 0.61 0.37 1.50 449 16,075 7,577 263 263 15,812 0.36 297.57 TOTAL RAINFALL 1.57 in RAINFALL VOLUME 22,878 cu-ft SOIL LOSSES 5,041 cu-ft EFFECTIVE RAIN 1.22 in FLOOD VOLUME 0.41 acft FLOOD VOLUME 17,837 cu-ft REQUIRED STORAGE 0.36 REQUIRED STORAGE 15,812 cu-ft MAX WSEL 297.57 ft PEAK FLOW RATE 24.91 cfs TOTAL BASIN LOSSES 2,025 cu-ft AVERAGE PERCOLATION RATE 33.75 cf/min Del Webb Explore at Palm DesertRCFC & WCD HYDROLOGY MANUAL SYNTHETIC UNIT HYDROGRAPH METHOD SHORTCUT METHOD 1-HOUR STORM EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Total In Basin in/hr Time Loss Rate Basin Losses Plate E-2.2 1-Hour Storm Page 4 of 13 PROJECT: Job No.:2636 BY:RJB DATE DRAINAGE AREA-ACRES 4.01 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 2.67 Maxwell Drywells UNIT TIME-PERCENT OF LAG 186.9 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.27 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.35 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 5 0.08 1.3 0.35 0.35 0.30 0.01 0.03 10 10 2,433 84 10 0 0.00 294.50 2 10 0.17 1.3 0.35 0.35 0.30 0.01 0.03 10 10 2,433 84 10 0 0.00 294.50 3 15 0.25 1.1 0.30 0.35 0.25 0.04 0.18 55 55 2,467 86 55 0 0.00 294.50 4 20 0.33 1.5 0.41 0.35 0.35 0.06 0.25 76 76 2,483 86 76 0 0.00 294.50 5 25 0.42 1.5 0.41 0.35 0.35 0.06 0.25 76 76 2,483 86 76 0 0.00 294.50 6 30 0.50 1.8 0.49 0.35 0.42 0.14 0.58 175 175 2,558 89 89 86 0.00 294.53 7 35 0.58 1.5 0.41 0.35 0.35 0.06 0.25 76 163 2,548 88 88 74 0.00 294.52 8 40 0.67 1.8 0.49 0.35 0.42 0.14 0.58 175 249 2,614 91 91 159 0.00 294.55 9 45 0.75 1.8 0.49 0.35 0.42 0.14 0.58 175 334 2,678 93 93 241 0.01 294.58 10 50 0.83 1.5 0.41 0.35 0.35 0.06 0.25 76 317 2,665 93 93 225 0.01 294.58 11 55 0.92 1.6 0.44 0.35 0.37 0.09 0.36 109 334 2,677 93 93 241 0.01 294.58 12 60 1.00 1.8 0.49 0.35 0.42 0.14 0.58 175 416 2,740 95 95 321 0.01 294.61 13 65 1.08 2.2 0.60 0.35 0.51 0.25 1.03 308 629 2,900 101 101 528 0.01 294.68 14 70 1.17 2.2 0.60 0.35 0.51 0.25 1.03 308 836 3,056 106 106 729 0.02 294.75 15 75 1.25 2.2 0.60 0.35 0.51 0.25 1.03 308 1,037 3,208 111 111 926 0.02 294.81 16 80 1.33 2.0 0.54 0.35 0.46 0.20 0.80 241 1,167 3,306 115 115 1,052 0.02 294.85 17 85 1.42 2.6 0.71 0.35 0.60 0.36 1.47 440 1,492 3,548 123 123 1,369 0.03 294.96 18 90 1.50 2.7 0.74 0.35 0.63 0.39 1.58 473 1,842 3,670 127 127 1,715 0.04 295.05 19 95 1.58 2.4 0.65 0.35 0.56 0.31 1.25 374 2,088 3,755 130 130 1,958 0.04 295.11 20 100 1.67 2.7 0.74 0.35 0.63 0.39 1.58 473 2,431 3,874 135 135 2,297 0.05 295.19 21 105 1.75 3.3 0.90 0.35 0.76 0.55 2.24 671 2,968 4,061 141 141 2,827 0.06 295.31 22 110 1.83 3.1 0.84 0.35 0.72 0.50 2.02 605 3,432 4,222 147 147 3,286 0.08 295.42 23 115 1.92 2.9 0.79 0.35 0.67 0.44 1.80 539 3,825 4,359 151 151 3,674 0.08 295.51 24 120 2.00 3.0 0.82 0.35 0.69 0.47 1.91 572 4,246 4,505 156 156 4,089 0.09 295.61 25 125 2.08 3.1 0.84 0.35 0.72 0.50 2.02 605 4,695 4,661 162 162 4,533 0.10 295.71 Total In Basin in/hr MANUAL 3-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Loss Rate Basin Losses RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Plate E-2.2 3-Hour Storm Page 5 of 13 PROJECT: Job No.:2636 BY:RJB DATE DRAINAGE AREA-ACRES 4.01 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 2.67 Maxwell Drywells UNIT TIME-PERCENT OF LAG 186.9 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.27 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.35 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft Total In Basin in/hr MANUAL 3-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Loss Rate Basin Losses RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD 26 130 2.17 4.2 1.14 0.35 0.97 0.80 3.23 969 5,502 4,941 172 172 5,331 0.12 295.90 27 135 2.25 5.0 1.36 0.35 1.16 1.02 4.11 1,234 6,564 5,258 183 183 6,382 0.15 296.11 28 140 2.33 3.5 0.95 0.35 0.81 0.61 2.46 738 7,119 5,416 188 188 6,931 0.16 296.20 29 145 2.42 6.8 1.85 0.35 1.57 1.51 6.10 1,829 8,761 5,882 204 204 8,556 0.20 296.48 30 150 2.50 7.3 1.99 0.35 1.69 1.64 6.65 1,995 10,551 6,390 222 222 10,329 0.24 296.79 31 155 2.58 8.2 2.23 0.35 1.90 1.89 7.64 2,292 12,622 6,889 239 239 12,382 0.28 297.11 32 160 2.67 5.9 1.61 0.35 1.37 1.26 5.11 1,532 13,914 7,147 248 248 13,666 0.31 297.28 33 165 2.75 2.0 0.54 0.35 0.46 0.20 0.80 241 13,907 7,145 248 248 13,659 0.31 297.28 34 170 2.83 1.8 0.49 0.35 0.42 0.14 0.58 175 13,834 7,131 248 248 13,587 0.31 297.27 35 175 2.92 1.8 0.49 0.35 0.42 0.14 0.58 175 13,762 7,116 247 247 13,515 0.31 297.26 36 180 3.00 0.6 0.16 0.35 0.14 0.02 0.10 30 13,545 7,073 246 246 13,299 0.31 297.23 TOTAL RAIN RAINFALL VOLUME SOIL LOSSES EFFECTIVE RAIN FLOOD VOLUME FLOOD VOLUME REQUIRED STORAGE REQUIRED STORAGE MAX WSEL PEAK FLOW RATE TOTAL BASIN LOSSES AVERAGE PERCOLATION RATE 14,761 cu-ft 2.27 in 33,078 cu-ft 297.28 ft 7.64 cfs 5,018 cu-ft 27.88 cf/min 1.26 in 0.42 acft 18,317 cu-ft 0.31 acft 13,666 cu-ft EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY Plate E-2.2 3-Hour Storm Page 6 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 4.01 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 2.67 Maxwell Drywells UNIT TIME-PERCENT OF LAG 186.9 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.98 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.35 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 5 0.08 0.5 0.18 0.35 0.15 0.03 0.11 33 33 2,450 85 33 0 0.00 294.50 2 10 0.17 0.6 0.21 0.35 0.18 0.03 0.13 39 39 2,455 85 39 0 0.00 294.50 3 15 0.25 0.6 0.21 0.35 0.18 0.03 0.13 39 39 2,455 85 39 0 0.00 294.50 4 20 0.33 0.6 0.21 0.35 0.18 0.03 0.13 39 39 2,455 85 39 0 0.00 294.50 5 25 0.42 0.6 0.21 0.35 0.18 0.03 0.13 39 39 2,455 85 39 0 0.00 294.50 6 30 0.50 0.7 0.25 0.35 0.21 0.04 0.15 46 46 2,460 85 46 0 0.00 294.50 7 35 0.58 0.7 0.25 0.35 0.21 0.04 0.15 46 46 2,460 85 46 0 0.00 294.50 8 40 0.67 0.7 0.25 0.35 0.21 0.04 0.15 46 46 2,460 85 46 0 0.00 294.50 9 45 0.75 0.7 0.25 0.35 0.21 0.04 0.15 46 46 2,460 85 46 0 0.00 294.50 10 50 0.83 0.7 0.25 0.35 0.21 0.04 0.15 46 46 2,460 85 46 0 0.00 294.50 11 55 0.92 0.7 0.25 0.35 0.21 0.04 0.15 46 46 2,460 85 46 0 0.00 294.50 12 60 1.00 0.8 0.29 0.35 0.24 0.04 0.17 52 52 2,465 86 52 0 0.00 294.50 13 65 1.08 0.8 0.29 0.35 0.24 0.04 0.17 52 52 2,465 86 52 0 0.00 294.50 14 70 1.17 0.8 0.29 0.35 0.24 0.04 0.17 52 52 2,465 86 52 0 0.00 294.50 15 75 1.25 0.8 0.29 0.35 0.24 0.04 0.17 52 52 2,465 86 52 0 0.00 294.50 16 80 1.33 0.8 0.29 0.35 0.24 0.04 0.17 52 52 2,465 86 52 0 0.00 294.50 17 85 1.42 0.8 0.29 0.35 0.24 0.04 0.17 52 52 2,465 86 52 0 0.00 294.50 18 90 1.50 0.8 0.29 0.35 0.24 0.04 0.17 52 52 2,465 86 52 0 0.00 294.50 19 95 1.58 0.8 0.29 0.35 0.24 0.04 0.17 52 52 2,465 86 52 0 0.00 294.50 20 100 1.67 0.8 0.29 0.35 0.24 0.04 0.17 52 52 2,465 86 52 0 0.00 294.50 21 105 1.75 0.8 0.29 0.35 0.24 0.04 0.17 52 52 2,465 86 52 0 0.00 294.50 22 110 1.83 0.8 0.29 0.35 0.24 0.04 0.17 52 52 2,465 86 52 0 0.00 294.50 23 115 1.92 0.8 0.29 0.35 0.24 0.04 0.17 52 52 2,465 86 52 0 0.00 294.50 24 120 2.00 0.9 0.32 0.35 0.27 0.05 0.20 59 59 2,470 86 59 0 0.00 294.50 Loss Rate RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 6-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Basin Losses Plate E-2.2 6-Hour Storm Page 7 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 4.01 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 2.67 Maxwell Drywells UNIT TIME-PERCENT OF LAG 186.9 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.98 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.35 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft Loss Rate RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 6-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Basin Losses 25 125 2.08 0.8 0.29 0.35 0.24 0.04 0.17 52 52 2,465 86 52 0 0.00 294.50 26 130 2.17 0.9 0.32 0.35 0.27 0.05 0.20 59 59 2,470 86 59 0 0.00 294.50 27 135 2.25 0.9 0.32 0.35 0.27 0.05 0.20 59 59 2,470 86 59 0 0.00 294.50 28 140 2.33 0.9 0.32 0.35 0.27 0.05 0.20 59 59 2,470 86 59 0 0.00 294.50 29 145 2.42 0.9 0.32 0.35 0.27 0.05 0.20 59 59 2,470 86 59 0 0.00 294.50 30 150 2.50 0.9 0.32 0.35 0.27 0.05 0.20 59 59 2,470 86 59 0 0.00 294.50 31 155 2.58 0.9 0.32 0.35 0.27 0.05 0.20 59 59 2,470 86 59 0 0.00 294.50 32 160 2.67 0.9 0.32 0.35 0.27 0.05 0.20 59 59 2,470 86 59 0 0.00 294.50 33 165 2.75 1.0 0.36 0.35 0.30 0.01 0.05 14 14 2,436 85 14 0 0.00 294.50 34 170 2.83 1.0 0.36 0.35 0.30 0.01 0.05 14 14 2,436 85 14 0 0.00 294.50 35 175 2.92 1.0 0.36 0.35 0.30 0.01 0.05 14 14 2,436 85 14 0 0.00 294.50 36 180 3.00 1.0 0.36 0.35 0.30 0.01 0.05 14 14 2,436 85 14 0 0.00 294.50 37 185 3.08 1.0 0.36 0.35 0.30 0.01 0.05 14 14 2,436 85 14 0 0.00 294.50 38 190 3.17 1.1 0.39 0.35 0.33 0.05 0.19 58 58 2,469 86 58 0 0.00 294.50 39 195 3.25 1.1 0.39 0.35 0.33 0.05 0.19 58 58 2,469 86 58 0 0.00 294.50 40 200 3.33 1.1 0.39 0.35 0.33 0.05 0.19 58 58 2,469 86 58 0 0.00 294.50 41 205 3.42 1.2 0.43 0.35 0.36 0.08 0.34 101 101 2,502 87 87 14 0.00 294.50 42 210 3.50 1.3 0.46 0.35 0.40 0.12 0.48 144 159 2,545 88 88 70 0.00 294.52 43 215 3.58 1.4 0.50 0.35 0.43 0.15 0.63 188 258 2,620 91 91 167 0.00 294.56 44 220 3.67 1.4 0.50 0.35 0.43 0.15 0.63 188 355 2,693 94 94 261 0.01 294.59 45 225 3.75 1.5 0.54 0.35 0.46 0.19 0.77 231 493 2,797 97 97 396 0.01 294.63 46 230 3.83 1.5 0.54 0.35 0.46 0.19 0.77 231 627 2,899 101 101 526 0.01 294.68 47 235 3.92 1.6 0.57 0.35 0.49 0.23 0.92 275 801 3,030 105 105 696 0.02 294.73 48 240 4.00 1.6 0.57 0.35 0.49 0.23 0.92 275 970 3,158 110 110 861 0.02 294.79 49 245 4.08 1.7 0.61 0.35 0.52 0.26 1.06 318 1,179 3,315 115 115 1,064 0.02 294.86 50 250 4.17 1.8 0.64 0.35 0.55 0.30 1.21 362 1,425 3,501 122 122 1,304 0.03 294.94 Plate E-2.2 6-Hour Storm Page 8 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 4.01 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 2.67 Maxwell Drywells UNIT TIME-PERCENT OF LAG 186.9 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.98 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.35 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft Loss Rate RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 6-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Basin Losses 51 255 4.25 1.9 0.68 0.35 0.58 0.33 1.35 405 1,709 3,623 126 126 1,583 0.04 295.02 52 260 4.33 2.0 0.72 0.35 0.61 0.37 1.49 448 2,031 3,735 130 130 1,902 0.04 295.10 53 265 4.42 2.1 0.75 0.35 0.64 0.41 1.64 492 2,393 3,861 134 134 2,259 0.05 295.18 54 270 4.50 2.1 0.75 0.35 0.64 0.41 1.64 492 2,751 3,986 138 138 2,613 0.06 295.26 55 275 4.58 2.2 0.79 0.35 0.67 0.44 1.78 535 3,148 4,123 143 143 3,005 0.07 295.36 56 280 4.67 2.3 0.82 0.35 0.70 0.48 1.93 579 3,583 4,275 148 148 3,435 0.08 295.46 57 285 4.75 2.4 0.86 0.35 0.73 0.51 2.07 622 4,057 4,439 154 154 3,903 0.09 295.57 58 290 4.83 2.4 0.86 0.35 0.73 0.51 2.07 622 4,525 4,602 160 160 4,365 0.10 295.68 59 295 4.92 2.5 0.89 0.35 0.76 0.55 2.22 666 5,031 4,777 166 166 4,865 0.11 295.79 60 300 5.00 2.6 0.93 0.35 0.79 0.58 2.36 709 5,574 4,966 172 172 5,401 0.12 295.92 61 305 5.08 3.1 1.11 0.35 0.94 0.76 3.09 926 6,328 5,191 180 180 6,147 0.14 296.07 62 310 5.17 3.6 1.29 0.35 1.09 0.94 3.81 1,143 7,290 5,464 190 190 7,101 0.16 296.23 63 315 5.25 3.9 1.39 0.35 1.19 1.05 4.24 1,273 8,374 5,772 200 200 8,174 0.19 296.42 64 320 5.33 4.2 1.50 0.35 1.28 1.16 4.68 1,404 9,577 6,113 212 212 9,365 0.21 296.62 65 325 5.42 4.7 1.68 0.35 1.43 1.33 5.40 1,621 10,986 6,513 226 226 10,760 0.25 296.86 66 330 5.50 5.6 2.00 0.35 1.70 1.66 6.71 2,012 12,772 6,919 240 240 12,531 0.29 297.13 67 335 5.58 1.9 0.68 0.35 0.58 0.33 1.35 405 12,936 6,952 241 241 12,695 0.29 297.15 68 340 5.67 0.9 0.32 0.35 0.27 0.05 0.20 59 12,754 6,916 240 240 12,513 0.29 297.13 69 345 5.75 0.6 0.21 0.35 0.18 0.03 0.13 39 12,553 6,876 239 239 12,314 0.28 297.10 70 350 5.83 0.5 0.18 0.35 0.15 0.03 0.11 33 12,346 6,835 237 237 12,109 0.28 297.07 71 355 5.92 0.3 0.11 0.35 0.09 0.02 0.07 20 12,129 6,791 236 236 11,893 0.27 297.04 72 360 6.00 0.2 0.07 0.35 0.06 0.01 0.04 13 11,906 6,747 234 234 11,672 0.27 297.01 TOTAL RAINFALL RAINFALL VOLUME SOIL LOSSES EFFECTIVE RAIN FLOOD VOLUME FLOOD VOLUME REQUIRED STORAGE REQUIRED STORAGE MAX WSEL PEAK FLOW RATE TOTAL BASIN LOSSES AVERAGE PERCOLATION RATE 43,424 cu-ft 2.98 in 24,743 cu-ft 297.15 ft 6.71 cfs 19.47 cf/min 7,010 cu-ft 1.28 in 0.43 acft 18,681 cu-ft 0.29 acft 12,695 cu-ft EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY Plate E-2.2 6-Hour Storm Page 9 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 4.01 VARIABLE LOSS RATE (AVG) IN/HR Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 15 Fm = Minimum value on loss curve (in/hr)0.17 LAG TIME - MINUTES 2.67 C 0.00320 Maxwell Drywells UNIT TIME-PERCENT OF LAG 561%Low Loss Rate (percent)85.00%Number 0 TOTAL ADJUSTED STORM RAIN (in)4.59 Drywell Percolation Rate 0.00 cfs 0.00 cfm Unit Time Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 15 0.25 0.2 0.037 0.611 0.031 0.01 0.02 20 20 2,441 254 20 0 0.00 294.50 2 30 0.50 0.3 0.055 0.604 0.047 0.01 0.03 30 30 2,448 255 30 0 0.00 294.50 3 45 0.75 0.3 0.055 0.597 0.047 0.01 0.03 30 30 2,448 255 30 0 0.00 294.50 4 60 1.00 0.4 0.073 0.590 0.062 0.01 0.04 40 40 2,456 256 40 0 0.00 294.50 5 75 1.25 0.3 0.055 0.583 0.047 0.01 0.03 30 30 2,448 255 30 0 0.00 294.50 6 90 1.50 0.3 0.055 0.576 0.047 0.01 0.03 30 30 2,448 255 30 0 0.00 294.50 7 105 1.75 0.3 0.055 0.569 0.047 0.01 0.03 30 30 2,448 255 30 0 0.00 294.50 8 120 2.00 0.4 0.073 0.562 0.062 0.01 0.04 40 40 2,456 256 40 0 0.00 294.50 9 135 2.25 0.4 0.073 0.555 0.062 0.01 0.04 40 40 2,456 256 40 0 0.00 294.50 10 150 2.50 0.4 0.073 0.549 0.062 0.01 0.04 40 40 2,456 256 40 0 0.00 294.50 11 165 2.75 0.5 0.092 0.542 0.078 0.01 0.06 50 50 2,464 257 50 0 0.00 294.50 12 180 3.00 0.5 0.092 0.535 0.078 0.01 0.06 50 50 2,464 257 50 0 0.00 294.50 13 195 3.25 0.5 0.092 0.529 0.078 0.01 0.06 50 50 2,464 257 50 0 0.00 294.50 14 210 3.50 0.5 0.092 0.522 0.078 0.01 0.06 50 50 2,464 257 50 0 0.00 294.50 15 225 3.75 0.5 0.092 0.515 0.078 0.01 0.06 50 50 2,464 257 50 0 0.00 294.50 16 240 4.00 0.6 0.110 0.509 0.094 0.02 0.07 60 60 2,471 257 60 0 0.00 294.50 17 255 4.25 0.6 0.110 0.503 0.094 0.02 0.07 60 60 2,471 257 60 0 0.00 294.50 18 270 4.50 0.7 0.129 0.496 0.109 0.02 0.08 70 70 2,479 258 70 0 0.00 294.50 19 285 4.75 0.7 0.129 0.490 0.109 0.02 0.08 70 70 2,479 258 70 0 0.00 294.50 20 300 5.00 0.8 0.147 0.483 0.125 0.02 0.09 80 80 2,486 259 80 0 0.00 294.50 21 315 5.25 0.6 0.110 0.477 0.094 0.02 0.07 60 60 2,471 257 60 0 0.00 294.50 22 330 5.50 0.7 0.129 0.471 0.109 0.02 0.08 70 70 2,479 258 70 0 0.00 294.50 23 345 5.75 0.8 0.147 0.465 0.125 0.02 0.09 80 80 2,486 259 80 0 0.00 294.50 24 360 6.00 0.8 0.147 0.459 0.125 0.02 0.09 80 80 2,486 259 80 0 0.00 294.50 25 375 6.25 0.9 0.165 0.453 0.140 0.02 0.10 90 90 2,494 260 90 0 0.00 294.50 26 390 6.50 0.9 0.165 0.447 0.140 0.02 0.10 90 90 2,494 260 90 0 0.00 294.50 27 405 6.75 1.0 0.184 0.441 0.156 0.03 0.11 100 100 2,501 261 100 0 0.00 294.50 28 420 7.00 1.0 0.184 0.435 0.156 0.03 0.11 100 100 2,501 261 100 0 0.00 294.50 29 435 7.25 1.0 0.184 0.429 0.156 0.03 0.11 100 100 2,501 261 100 0 0.00 294.50 30 450 7.50 1.1 0.202 0.423 0.172 0.03 0.12 110 110 2,509 261 110 0 0.00 294.50 31 465 7.75 1.2 0.220 0.417 0.187 0.03 0.13 120 120 2,517 262 120 0 0.00 294.50 32 480 8.00 1.3 0.239 0.411 0.203 0.04 0.14 130 130 2,524 263 130 0 0.00 294.50 33 495 8.25 1.5 0.275 0.406 0.234 0.04 0.17 150 150 2,539 265 150 0 0.00 294.50 34 510 8.50 1.5 0.275 0.400 0.234 0.04 0.17 150 150 2,539 265 150 0 0.00 294.50 35 525 8.75 1.6 0.294 0.394 0.250 0.04 0.18 161 161 2,547 265 161 0 0.00 294.50 36 540 9.00 1.7 0.312 0.389 0.265 0.05 0.19 171 171 2,554 266 171 0 0.00 294.50 37 555 9.25 1.9 0.349 0.383 0.297 0.05 0.21 191 191 2,569 268 191 0 0.00 294.50 38 570 9.50 2.0 0.367 0.378 0.312 0.06 0.22 201 201 2,577 268 201 0 0.00 294.50 39 585 9.75 2.1 0.386 0.372 0.328 0.01 0.05 48 48 2,462 256 48 0 0.00 294.50 40 600 10.00 2.2 0.404 0.367 0.343 0.04 0.15 134 134 2,527 263 134 0 0.00 294.50 41 615 10.25 1.5 0.275 0.362 0.234 0.04 0.17 150 150 2,539 265 150 0 0.00 294.50 42 630 10.50 1.5 0.275 0.357 0.234 0.04 0.17 150 150 2,539 265 150 0 0.00 294.50 43 645 10.75 2.0 0.367 0.351 0.312 0.02 0.06 58 58 2,469 257 58 0 0.00 294.50 RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Loss Rate Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD MANUAL 24-HOUR STORM Basin Losses in/hr Total In Basin UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Plate E-2.2 24-Hour Storm Page 10 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 4.01 VARIABLE LOSS RATE (AVG) IN/HR Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 15 Fm = Minimum value on loss curve (in/hr)0.17 LAG TIME - MINUTES 2.67 C 0.00320 Maxwell Drywells UNIT TIME-PERCENT OF LAG 561%Low Loss Rate (percent)85.00%Number 0 TOTAL ADJUSTED STORM RAIN (in)4.59 Drywell Percolation Rate 0.00 cfs 0.00 cfm Unit Time Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Loss Rate Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD MANUAL 24-HOUR STORM Basin Losses in/hr Total In Basin UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM 44 660 11.00 2.0 0.367 0.346 0.312 0.02 0.08 76 76 2,483 259 76 0 0.00 294.50 45 675 11.25 1.9 0.349 0.341 0.297 0.01 0.03 28 28 2,447 255 28 0 0.00 294.50 46 690 11.50 1.9 0.349 0.336 0.297 0.01 0.05 46 46 2,461 256 46 0 0.00 294.50 47 705 11.75 1.7 0.312 0.331 0.265 0.05 0.19 171 171 2,554 266 171 0 0.00 294.50 48 720 12.00 1.8 0.330 0.326 0.281 0.00 0.02 16 16 2,437 254 16 0 0.00 294.50 49 735 12.25 2.5 0.459 0.321 0.390 0.14 0.56 502 502 2,804 292 292 209 0.00 294.57 50 750 12.50 2.6 0.477 0.317 0.406 0.16 0.65 586 795 3,026 315 315 480 0.01 294.66 51 765 12.75 2.8 0.514 0.312 0.437 0.20 0.82 737 1,217 3,344 348 348 869 0.02 294.79 52 780 13.00 2.9 0.532 0.307 0.453 0.23 0.91 821 1,690 3,617 377 377 1,313 0.03 294.94 53 795 13.25 3.4 0.624 0.302 0.531 0.32 1.30 1,172 2,486 3,893 406 406 2,080 0.05 295.14 54 810 13.50 3.4 0.624 0.298 0.531 0.33 1.32 1,189 3,269 4,166 434 434 2,835 0.07 295.32 55 825 13.75 2.3 0.422 0.293 0.359 0.13 0.52 470 3,305 4,178 435 435 2,870 0.07 295.33 56 840 14.00 2.3 0.422 0.289 0.359 0.13 0.54 486 3,356 4,196 437 437 2,919 0.07 295.34 57 855 14.25 2.7 0.496 0.284 0.421 0.21 0.86 770 3,689 4,311 449 449 3,240 0.07 295.41 58 870 14.50 2.6 0.477 0.280 0.406 0.20 0.80 719 3,958 4,405 459 459 3,500 0.08 295.47 59 885 14.75 2.6 0.477 0.276 0.406 0.20 0.82 734 4,234 4,501 469 469 3,765 0.09 295.53 60 900 15.00 2.5 0.459 0.272 0.390 0.19 0.76 683 4,448 4,575 477 477 3,971 0.09 295.58 61 915 15.25 2.4 0.441 0.267 0.375 0.17 0.70 631 4,602 4,629 482 482 4,120 0.09 295.62 62 930 15.50 2.3 0.422 0.263 0.359 0.16 0.64 579 4,699 4,662 486 486 4,213 0.10 295.64 63 945 15.75 1.9 0.349 0.259 0.297 0.09 0.36 326 4,540 4,607 480 480 4,060 0.09 295.60 64 960 16.00 1.9 0.349 0.255 0.297 0.09 0.38 341 4,400 4,558 475 475 3,925 0.09 295.57 65 975 16.25 0.4 0.073 0.251 0.062 0.01 0.04 40 3,966 4,407 459 459 3,506 0.08 295.47 66 990 16.50 0.4 0.073 0.248 0.062 0.01 0.04 40 3,547 4,262 444 444 3,103 0.07 295.38 67 1005 16.75 0.3 0.055 0.244 0.047 0.01 0.03 30 3,133 4,118 429 429 2,704 0.06 295.29 68 1020 17.00 0.3 0.055 0.240 0.047 0.01 0.03 30 2,734 3,980 415 415 2,319 0.05 295.20 69 1035 17.25 0.5 0.092 0.237 0.078 0.01 0.06 50 2,370 3,853 401 401 1,968 0.05 295.11 70 1050 17.50 0.5 0.092 0.233 0.078 0.01 0.06 50 2,018 3,731 389 389 1,630 0.04 295.03 71 1065 17.75 0.5 0.092 0.230 0.078 0.01 0.06 50 1,680 3,613 376 376 1,303 0.03 294.94 72 1080 18.00 0.4 0.073 0.226 0.062 0.01 0.04 40 1,344 3,439 358 358 985 0.02 294.83 73 1095 18.25 0.4 0.073 0.223 0.062 0.01 0.04 40 1,025 3,199 333 333 692 0.02 294.73 74 1110 18.50 0.4 0.073 0.220 0.062 0.01 0.04 40 732 2,978 310 310 422 0.01 294.64 75 1125 18.75 0.3 0.055 0.216 0.047 0.01 0.03 30 452 2,767 288 288 164 0.00 294.56 76 1140 19.00 0.2 0.037 0.213 0.031 0.01 0.02 20 184 2,565 267 184 0 0.00 294.50 77 1155 19.25 0.3 0.055 0.210 0.047 0.01 0.03 30 30 2,448 255 30 0 0.00 294.50 78 1170 19.50 0.4 0.073 0.207 0.062 0.01 0.04 40 40 2,456 256 40 0 0.00 294.50 79 1185 19.75 0.3 0.055 0.205 0.047 0.01 0.03 30 30 2,448 255 30 0 0.00 294.50 80 1200 20.00 0.2 0.037 0.202 0.031 0.01 0.02 20 20 2,441 254 20 0 0.00 294.50 81 1215 20.25 0.3 0.055 0.199 0.047 0.01 0.03 30 30 2,448 255 30 0 0.00 294.50 82 1230 20.50 0.3 0.055 0.197 0.047 0.01 0.03 30 30 2,448 255 30 0 0.00 294.50 83 1245 20.75 0.3 0.055 0.194 0.047 0.01 0.03 30 30 2,448 255 30 0 0.00 294.50 84 1260 21.00 0.2 0.037 0.192 0.031 0.01 0.02 20 20 2,441 254 20 0 0.00 294.50 85 1275 21.25 0.3 0.055 0.189 0.047 0.01 0.03 30 30 2,448 255 30 0 0.00 294.50 86 1290 21.50 0.2 0.037 0.187 0.031 0.01 0.02 20 20 2,441 254 20 0 0.00 294.50 Plate E-2.2 24-Hour Storm Page 11 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 4.01 VARIABLE LOSS RATE (AVG) IN/HR Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 15 Fm = Minimum value on loss curve (in/hr)0.17 LAG TIME - MINUTES 2.67 C 0.00320 Maxwell Drywells UNIT TIME-PERCENT OF LAG 561%Low Loss Rate (percent)85.00%Number 0 TOTAL ADJUSTED STORM RAIN (in)4.59 Drywell Percolation Rate 0.00 cfs 0.00 cfm Unit Time Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Loss Rate Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD MANUAL 24-HOUR STORM Basin Losses in/hr Total In Basin UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM 87 1305 21.75 0.3 0.055 0.185 0.047 0.01 0.03 30 30 2,448 255 30 0 0.00 294.50 88 1320 22.00 0.2 0.037 0.183 0.031 0.01 0.02 20 20 2,441 254 20 0 0.00 294.50 89 1335 22.25 0.3 0.055 0.181 0.047 0.01 0.03 30 30 2,448 255 30 0 0.00 294.50 90 1350 22.50 0.2 0.037 0.180 0.031 0.01 0.02 20 20 2,441 254 20 0 0.00 294.50 91 1365 22.75 0.2 0.037 0.178 0.031 0.01 0.02 20 20 2,441 254 20 0 0.00 294.50 92 1380 23.00 0.2 0.037 0.177 0.031 0.01 0.02 20 20 2,441 254 20 0 0.00 294.50 93 1395 23.25 0.2 0.037 0.176 0.031 0.01 0.02 20 20 2,441 254 20 0 0.00 294.50 94 1410 23.50 0.2 0.037 0.175 0.031 0.01 0.02 20 20 2,441 254 20 0 0.00 294.50 95 1425 23.75 0.2 0.037 0.174 0.031 0.01 0.02 20 20 2,441 254 20 0 0.00 294.50 96 1440 24.00 0.2 0.037 0.173 0.031 0.01 0.02 20 20 2,441 254 20 0 0.00 294.50 EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY TOTAL RAINFALL RAINFALL VOLUME SOIL LOSSES EFFECTIVE RAIN FLOOD VOLUME FLOOD VOLUME REQUIRED STORAGE REQUIRED STORAGE MAX WSEL PEAK FLOW RATE TOTAL BASIN LOSSES AVERAGE PERCOLATION RATE 4.59 in 66,885 cu-ft 51,219 cu-ft 295.64 ft 1.32 cfs 15,667 cu-ft 10.88 cf/min 1.08 in 0.36 acft 15,667 cu-ft 0.10 acft 4,213 cu-ft Plate E-2.2 24-Hour Storm Page 12 of 13 PROECT JOB No. BASIN DESIGNATION: BASIN CHARACTERISTICS CONTOUR ELEVATION INCR TOTAL INCR TOTAL INCR (ft)(ft)(sf)(sf)(cuft)(cuft)(acre-ft) 294.5 0 0 2,426 0 0 0.00 295 0.5 0.5 1,120 3,545 1,484 1,484 0.03 296 1 1.5 1,482 5,027 4,265 5,748 0.13 297 1 2.5 1,656 6,683 5,835 11,584 0.27 298 1 3.5 1,475 8,157 7,408 18,991 0.44 299 1 4.5 1,489 9,646 8,891 27,883 0.64 WHERE: TOTAL Retention Basin BASIN VOLUME WORKSHEET DEPTH AREA VOLUME Del Webb Explore at Palm Desert 2636 ()()2121213 1 AAAAEEV++−= Basin Volume Worksheet Page 13 of 13 RJB 2 AMC II AREA SOIL TRIBUTARY AREAS ACRES LOW LOSS RI INFILTRATION IMPERVIOUS DESIG GROUP CONDITION NUMBER RATE PERCENT 4 A SF - DETACHED 2.613 D 32 0.74 0.50 9 A LANDSCAPING 0.548 D 32 0.74 0.10 2 A PAVING/HARDSCAPE 1.184 D 32 0.74 1.00 862 ft 431 ft 307.4 ft ELEVATION OF CONCENTRATION POINT 298.9 ft 0.02 100 LOW LOSS RATE (Storm Events > 10 Years)85% POINT RAIN FROM NOAA ATLAS 14 1-HOUR 1.57 in 3-HOUR 2.27 in 6-HOUR 2.98 in 24-HOUR 4.59 in BASIN CHARACTERISTICS:ELEVATION AREA 294.0 ft 3,738 sf 295.0 ft 5,450 sf 296.0 ft 7,070 sf 297.0 ft 8,505 sf 298.0 ft 10,028 sf PERCOLATION RATE (in/hr)5.0 in/hr DRYWELL DATA NUMBER USED PERCOLATION RATE LOWEST FLOWLINE ELEVATION 298.85 LOWEST PAD ELEVATION 301.5 LENGTH OF WATERCOURSE (L) AREA DESIGNATION ELEVATION OF HEADWATER AVERAGE MANNINGS 'N' VALUE STORM FREQUENCY (YEAR) LENGTH TO POINT OPPOSITE CENTROID (Lca) Low Loss Conditions: X=Existing; D=Developed; BS=Retention DA-D RCFCD SYNTHETIC UNIT HYDROGRAPH - SHORTCUT METHOD DATA INPUT SHEET WORKSHEET PREPARED BY: PROJECT NAME DATE January 9, 2024 Del Webb Explore at Palm Desert PROJECT NUMBER CONCENTRATION POINT DESIGNATION 2636 Retention Basin- D AMC NUMBER Data Input Sheet Page 1 of 13 PROJECT: Job No.: BY:DATE:1/9/24 [1] AMC II [2] FREQUENCY-YEARS 100 FROM NOAA ATLAS 14 [3] STORM DURATION:Point Rain 1-HOUR 1.57 in 3-HOUR 2.27 in 6-HOUR 2.98 in 24-HOUR 4.59 in STORM DURATION 1-HOUR 3-HOUR 6-HOUR 24-HOUR RAINFALL VOLUME (cu-ft)24,764 35,805 47,004 72,399 SOIL LOSSES (cu-ft)5,518 16,152 26,962 55,753 EFFECTIVE RAIN (in)1.22 1.25 1.27 1.06 FLOOD VOLUME (cu-ft)19,246 19,653 20,042 16,645 (acre-ft)0.44 0.45 0.46 0.38 REQUIRED STORAGE (cu-ft)16,876 14,177 13,175 3,739 (acre-ft)0.39 0.33 0.30 0.09 FACTOR OF SAFETY 1.65 1.96 2.11 7.45 STORAGE PROVIDED (cu-ft) (acre-ft) PEAK FLOW (cfs)n/a 8.25 7.24 1.42 MAXIMUM WSEL (ft)296.78 296.43 296.30 294.82 DEPTH (ft)2.78 2.43 2.30 0.82 DIFFERENCE (ft)2.07 2.42 2.55 4.03 DIFFERENCE (ft)4.72 5.07 5.20 6.68 ESTIMATED TIME TO DEWATER BASIN Based on Total Flood Volume & Average Percolation Rate (days)0.3 0.4 0.6 1.0 [18] 200% OF LAG-MINUTES RAINFALL DATA 5.3 NOTE: PEAK FLOW FOR THE 1-HOUR STORM IS NOT REPRESENTATIVE. PER RCFCD PEAK DISCHARGES FROM THE 3-HOUR STORM SHOULD NORMALLY COMPARE WELL WITH RATIONAL PEAKS. LOWEST PAD ELEVATION LOWEST FLOWLINE ELEVATION STORM EVENT SUMMARY 301.5 298.85 27,842 0.64 0.02 [17] 100% OF LAG-MINUTES 2.6 2.6 [14] AVERAGE MANNINGS 'N' [15] LAG TIME-HOURS 0.04 [16] LAG TIME-MINUTES [13] L*LCA/S^0.5 7.24 [11] S-FEET/MILE [6] La-FEET [7] La-MILES [8] ELEVATION OF HEADWATER 0.002 431.00 [12] S^0.5 0.082 52.4 307.4 298.85 8.55 [3] AREA - ACRES [4] L-FEET [5] L-MILES 862 0.163 Retention Basin- D DA-D Del Webb Explore at Palm Desert [10] H-FEET [9] ELEVATION OF CONCENTRATION POINT 4.345 PHYSICAL DATA [1] CONCENTRATION POINT HYDROLOGY MANUAL BASIC DATA CALCULATION FORM 2636 RJB RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD [2] AREA DESIGNATION Plate E-2.1 Page 2 of 13 PROJECT: Job No.: BY:DATE:1/9/24 MAX LOW LOW MIN SOIL RI PERVIOUS DECIMAL ADJUSTED AREA AREA AVERAGE LOSS LOSS RATE AVERAGE GROUP NUMBER AREA PERCENT INFILTRATION WEIGHTED ADJUSTED CONDITION PER ADJUSTED INFILTRATION OF AREA RATE AVERAGE INFILTRATION RCFC/2322 INFILTRATION RATE IMPERVIOUS RATE RATE (in/hr)(in/hr)(in/hr) [Plate C-1][Plate E-6.1][Plate E-6.2][Plate E-6.3] A 32 0.74 50%0.41 2.613 0.601 0.2448 DEVELOPED 0.5000 0.3007 A 32 0.74 10%0.67 0.548 0.126 0.0849 DEVELOPED 0.8200 0.1034 A 32 0.74 100%0.07 1.184 0.273 0.0202 DEVELOPED 0.1000 0.0273 SUM 4.345 SUM 0.3498 0.4313 VARIABLE LOSS RATE CURVE (24-HOUR STORM ONLY) Fm=0.174922328 NOTE: Low loss rates established per RCFC/2322 (Dated: May-30-95) C=0.00324 For 10 Year Storms or Less Ft=C(24-(T/60))^1.55+Fm =0.00324 0.17 in/hr Undeveloped Condition: Low Loss = 90% CONSTANT LOSS RATE (3 & 6 HOUR STORMS)=0.3498 Developed Condition: Low Loss = 0.9 - (0.8 * %impervious) LOW LOSS RATE =0.8500 Basin Site: Low Loss = 10% Where:For 100 Year Storm - Low Loss should be between 80% & 90% T=Time in minutes. To get an average value for each unit time period, Use T=1/2 the unit time for the first time period,of the Rainfall Rate T=1 1/2 unit time for the second period, etc. (24-(T/60))^1.55 + LAND USE SF - DETACHED LANDSCAPING PAVING/HARDSCAPE AVERAGE ADJUSTED LOSS RATE RCFC & WCD HYDROLOGY MANUAL SYNTHETIC UNIT HYDROGRAPH METHOD BASIC DATA CALCULATION FORM Del Webb Explore at Palm Desert RJB 2636 AMC II Plate E-2.1 Page 3 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 4.35 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 2.63 Maxwell Drywells UNIT TIME-PERCENT OF LAG 190.0 Number 0 TOTAL ADJUSTED STORM RAIN-INCHES 1.57 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE-in/hr 0.35 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 5 0.08 3.6 0.68 0.35 0.58 0.33 1.44 432 432 3,900 135 135 296 0.01 294.06 2 10 0.17 4.2 0.79 0.35 0.67 0.44 1.93 580 876 4,067 141 141 735 0.02 294.16 3 15 0.25 4.4 0.83 0.35 0.70 0.48 2.10 630 1,365 4,250 148 148 1,217 0.03 294.27 4 20 0.33 4.6 0.87 0.35 0.74 0.52 2.26 679 1,897 4,449 154 154 1,742 0.04 294.38 5 25 0.42 5.0 0.94 0.35 0.80 0.59 2.59 778 2,521 4,683 163 163 2,358 0.05 294.52 6 30 0.50 5.6 1.06 0.35 0.90 0.71 3.09 927 3,285 4,969 173 173 3,112 0.07 294.68 7 35 0.58 6.4 1.21 0.35 1.02 0.86 3.75 1,125 4,237 5,326 185 185 4,053 0.09 294.89 8 40 0.67 8.1 1.53 0.35 1.30 1.18 5.15 1,546 5,599 5,718 199 199 5,400 0.12 295.13 9 45 0.75 13.1 2.47 0.35 2.10 2.12 9.28 2,784 8,184 6,389 222 222 7,962 0.18 295.54 10 50 0.83 34.5 6.50 0.35 5.52 6.15 26.95 8,084 16,046 8,036 279 279 15,767 0.36 296.64 11 55 0.92 6.7 1.26 0.35 1.07 0.91 4.00 1,199 16,966 8,206 285 285 16,681 0.38 296.76 12 60 1.00 3.8 0.72 0.35 0.61 0.37 1.60 481 17,163 8,242 286 286 16,876 0.39 296.78 TOTAL RAINFALL 1.57 in RAINFALL VOLUME 24,764 cu-ft SOIL LOSSES 5,518 cu-ft EFFECTIVE RAIN 1.22 in FLOOD VOLUME 0.44 acft FLOOD VOLUME 19,246 cu-ft REQUIRED STORAGE 0.39 REQUIRED STORAGE 16,876 cu-ft MAX WSEL 296.78 ft PEAK FLOW RATE 26.95 cfs TOTAL BASIN LOSSES 2,369 cu-ft AVERAGE PERCOLATION RATE 39.49 cf/min EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Total In Basin in/hr Time Loss Rate Basin Losses Del Webb Explore at Palm DesertRCFC & WCD HYDROLOGY MANUAL SYNTHETIC UNIT HYDROGRAPH METHOD SHORTCUT METHOD 1-HOUR STORM Plate E-2.2 1-Hour Storm Page 4 of 13 PROJECT: Job No.:2636 BY:RJB DATE DRAINAGE AREA-ACRES 4.35 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 2.63 Maxwell Drywells UNIT TIME-PERCENT OF LAG 190.0 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.27 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.35 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 5 0.08 1.3 0.35 0.35 0.30 0.00 0.02 6 6 3,740 130 6 0 0.00 294.00 2 10 0.17 1.3 0.35 0.35 0.30 0.00 0.02 6 6 3,740 130 6 0 0.00 294.00 3 15 0.25 1.1 0.30 0.35 0.25 0.04 0.20 59 59 3,760 131 59 0 0.00 294.00 4 20 0.33 1.5 0.41 0.35 0.35 0.06 0.26 77 77 3,767 131 77 0 0.00 294.00 5 25 0.42 1.5 0.41 0.35 0.35 0.06 0.26 77 77 3,767 131 77 0 0.00 294.00 6 30 0.50 1.8 0.49 0.35 0.42 0.14 0.62 185 185 3,807 132 132 52 0.00 294.01 7 35 0.58 1.5 0.41 0.35 0.35 0.06 0.26 77 130 3,787 131 130 0 0.00 294.00 8 40 0.67 1.8 0.49 0.35 0.42 0.14 0.62 185 185 3,807 132 132 52 0.00 294.01 9 45 0.75 1.8 0.49 0.35 0.42 0.14 0.62 185 237 3,827 133 133 104 0.00 294.02 10 50 0.83 1.5 0.41 0.35 0.35 0.06 0.26 77 181 3,806 132 132 49 0.00 294.01 11 55 0.92 1.6 0.44 0.35 0.37 0.09 0.38 113 162 3,799 132 132 30 0.00 294.01 12 60 1.00 1.8 0.49 0.35 0.42 0.14 0.62 185 215 3,819 133 133 82 0.00 294.02 13 65 1.08 2.2 0.60 0.35 0.51 0.25 1.09 328 410 3,892 135 135 275 0.01 294.06 14 70 1.17 2.2 0.60 0.35 0.51 0.25 1.09 328 603 3,964 138 138 465 0.01 294.10 15 75 1.25 2.2 0.60 0.35 0.51 0.25 1.09 328 793 4,035 140 140 653 0.01 294.14 16 80 1.33 2.0 0.54 0.35 0.46 0.19 0.85 256 909 4,079 142 142 768 0.02 294.17 17 85 1.42 2.6 0.71 0.35 0.60 0.36 1.57 471 1,239 4,202 146 146 1,093 0.03 294.24 18 90 1.50 2.7 0.74 0.35 0.63 0.39 1.69 507 1,600 4,338 151 151 1,449 0.03 294.32 19 95 1.58 2.4 0.65 0.35 0.56 0.30 1.33 399 1,849 4,431 154 154 1,695 0.04 294.37 20 100 1.67 2.7 0.74 0.35 0.63 0.39 1.69 507 2,202 4,563 158 158 2,043 0.05 294.45 21 105 1.75 3.3 0.90 0.35 0.76 0.55 2.41 722 2,765 4,774 166 166 2,599 0.06 294.57 22 110 1.83 3.1 0.84 0.35 0.72 0.49 2.17 650 3,249 4,956 172 172 3,077 0.07 294.67 23 115 1.92 2.9 0.79 0.35 0.67 0.44 1.93 578 3,656 5,108 177 177 3,478 0.08 294.76 24 120 2.00 3.0 0.82 0.35 0.69 0.47 2.05 614 4,093 5,272 183 183 3,910 0.09 294.86 25 125 2.08 3.1 0.84 0.35 0.72 0.49 2.17 650 4,560 5,447 189 189 4,371 0.10 294.96 RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 3-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Loss Rate Basin Losses Plate E-2.2 3-Hour Storm Page 5 of 13 PROJECT: Job No.:2636 BY:RJB DATE DRAINAGE AREA-ACRES 4.35 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 2.63 Maxwell Drywells UNIT TIME-PERCENT OF LAG 190.0 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.27 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.35 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 3-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Loss Rate Basin Losses 26 130 2.17 4.2 1.14 0.35 0.97 0.79 3.48 1,044 5,415 5,670 197 197 5,218 0.12 295.10 27 135 2.25 5.0 1.36 0.35 1.16 1.01 4.43 1,330 6,548 5,964 207 207 6,341 0.15 295.28 28 140 2.33 3.5 0.95 0.35 0.81 0.60 2.64 793 7,134 6,116 212 212 6,922 0.16 295.38 29 145 2.42 6.8 1.85 0.35 1.57 1.50 6.58 1,975 8,897 6,574 228 228 8,669 0.20 295.66 30 150 2.50 7.3 1.99 0.35 1.69 1.64 7.18 2,154 10,823 7,072 246 246 10,577 0.24 295.96 31 155 2.58 8.2 2.23 0.35 1.90 1.88 8.25 2,476 13,053 7,484 260 260 12,793 0.29 296.26 32 160 2.67 5.9 1.61 0.35 1.37 1.26 5.51 1,653 14,446 7,741 269 269 14,177 0.33 296.43 33 165 2.75 2.0 0.54 0.35 0.46 0.19 0.85 256 14,433 7,739 269 269 14,165 0.33 296.43 34 170 2.83 1.8 0.49 0.35 0.42 0.14 0.62 185 14,349 7,723 268 268 14,081 0.32 296.42 35 175 2.92 1.8 0.49 0.35 0.42 0.14 0.62 185 14,266 7,708 268 268 13,998 0.32 296.41 36 180 3.00 0.6 0.16 0.35 0.14 0.02 0.11 32 14,030 7,664 266 266 13,764 0.32 296.38 TOTAL RAIN RAINFALL VOLUME SOIL LOSSES EFFECTIVE RAIN FLOOD VOLUME FLOOD VOLUME REQUIRED STORAGE REQUIRED STORAGE MAX WSEL PEAK FLOW RATE TOTAL BASIN LOSSES AVERAGE PERCOLATION RATE EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY 5,889 cu-ft 32.71 cf/min 1.25 in 0.45 acft 19,653 cu-ft 0.33 acft 14,177 cu-ft 16,152 cu-ft 2.27 in 35,805 cu-ft 296.43 ft 8.25 cfs Plate E-2.2 3-Hour Storm Page 6 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 4.35 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 2.63 Maxwell Drywells UNIT TIME-PERCENT OF LAG 190.0 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.98 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.35 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 5 0.08 0.5 0.18 0.35 0.15 0.03 0.12 35 35 3,751 130 35 0 0.00 294.00 2 10 0.17 0.6 0.21 0.35 0.18 0.03 0.14 42 42 3,754 130 42 0 0.00 294.00 3 15 0.25 0.6 0.21 0.35 0.18 0.03 0.14 42 42 3,754 130 42 0 0.00 294.00 4 20 0.33 0.6 0.21 0.35 0.18 0.03 0.14 42 42 3,754 130 42 0 0.00 294.00 5 25 0.42 0.6 0.21 0.35 0.18 0.03 0.14 42 42 3,754 130 42 0 0.00 294.00 6 30 0.50 0.7 0.25 0.35 0.21 0.04 0.16 49 49 3,756 130 49 0 0.00 294.00 7 35 0.58 0.7 0.25 0.35 0.21 0.04 0.16 49 49 3,756 130 49 0 0.00 294.00 8 40 0.67 0.7 0.25 0.35 0.21 0.04 0.16 49 49 3,756 130 49 0 0.00 294.00 9 45 0.75 0.7 0.25 0.35 0.21 0.04 0.16 49 49 3,756 130 49 0 0.00 294.00 10 50 0.83 0.7 0.25 0.35 0.21 0.04 0.16 49 49 3,756 130 49 0 0.00 294.00 11 55 0.92 0.7 0.25 0.35 0.21 0.04 0.16 49 49 3,756 130 49 0 0.00 294.00 12 60 1.00 0.8 0.29 0.35 0.24 0.04 0.19 56 56 3,759 131 56 0 0.00 294.00 13 65 1.08 0.8 0.29 0.35 0.24 0.04 0.19 56 56 3,759 131 56 0 0.00 294.00 14 70 1.17 0.8 0.29 0.35 0.24 0.04 0.19 56 56 3,759 131 56 0 0.00 294.00 15 75 1.25 0.8 0.29 0.35 0.24 0.04 0.19 56 56 3,759 131 56 0 0.00 294.00 16 80 1.33 0.8 0.29 0.35 0.24 0.04 0.19 56 56 3,759 131 56 0 0.00 294.00 17 85 1.42 0.8 0.29 0.35 0.24 0.04 0.19 56 56 3,759 131 56 0 0.00 294.00 18 90 1.50 0.8 0.29 0.35 0.24 0.04 0.19 56 56 3,759 131 56 0 0.00 294.00 19 95 1.58 0.8 0.29 0.35 0.24 0.04 0.19 56 56 3,759 131 56 0 0.00 294.00 20 100 1.67 0.8 0.29 0.35 0.24 0.04 0.19 56 56 3,759 131 56 0 0.00 294.00 21 105 1.75 0.8 0.29 0.35 0.24 0.04 0.19 56 56 3,759 131 56 0 0.00 294.00 22 110 1.83 0.8 0.29 0.35 0.24 0.04 0.19 56 56 3,759 131 56 0 0.00 294.00 23 115 1.92 0.8 0.29 0.35 0.24 0.04 0.19 56 56 3,759 131 56 0 0.00 294.00 24 120 2.00 0.9 0.32 0.35 0.27 0.05 0.21 63 63 3,762 131 63 0 0.00 294.00 Loss Rate RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 6-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Basin Losses Plate E-2.2 6-Hour Storm Page 7 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 4.35 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 2.63 Maxwell Drywells UNIT TIME-PERCENT OF LAG 190.0 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.98 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.35 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft Loss Rate RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 6-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Basin Losses 25 125 2.08 0.8 0.29 0.35 0.24 0.04 0.19 56 56 3,759 131 56 0 0.00 294.00 26 130 2.17 0.9 0.32 0.35 0.27 0.05 0.21 63 63 3,762 131 63 0 0.00 294.00 27 135 2.25 0.9 0.32 0.35 0.27 0.05 0.21 63 63 3,762 131 63 0 0.00 294.00 28 140 2.33 0.9 0.32 0.35 0.27 0.05 0.21 63 63 3,762 131 63 0 0.00 294.00 29 145 2.42 0.9 0.32 0.35 0.27 0.05 0.21 63 63 3,762 131 63 0 0.00 294.00 30 150 2.50 0.9 0.32 0.35 0.27 0.05 0.21 63 63 3,762 131 63 0 0.00 294.00 31 155 2.58 0.9 0.32 0.35 0.27 0.05 0.21 63 63 3,762 131 63 0 0.00 294.00 32 160 2.67 0.9 0.32 0.35 0.27 0.05 0.21 63 63 3,762 131 63 0 0.00 294.00 33 165 2.75 1.0 0.36 0.35 0.30 0.01 0.03 10 10 3,742 130 10 0 0.00 294.00 34 170 2.83 1.0 0.36 0.35 0.30 0.01 0.03 10 10 3,742 130 10 0 0.00 294.00 35 175 2.92 1.0 0.36 0.35 0.30 0.01 0.03 10 10 3,742 130 10 0 0.00 294.00 36 180 3.00 1.0 0.36 0.35 0.30 0.01 0.03 10 10 3,742 130 10 0 0.00 294.00 37 185 3.08 1.0 0.36 0.35 0.30 0.01 0.03 10 10 3,742 130 10 0 0.00 294.00 38 190 3.17 1.1 0.39 0.35 0.33 0.04 0.19 57 57 3,759 131 57 0 0.00 294.00 39 195 3.25 1.1 0.39 0.35 0.33 0.04 0.19 57 57 3,759 131 57 0 0.00 294.00 40 200 3.33 1.1 0.39 0.35 0.33 0.04 0.19 57 57 3,759 131 57 0 0.00 294.00 41 205 3.42 1.2 0.43 0.35 0.36 0.08 0.35 104 104 3,777 131 104 0 0.00 294.00 42 210 3.50 1.3 0.46 0.35 0.40 0.12 0.50 151 151 3,795 132 132 19 0.00 294.00 43 215 3.58 1.4 0.50 0.35 0.43 0.15 0.66 198 218 3,820 133 133 85 0.00 294.02 44 220 3.67 1.4 0.50 0.35 0.43 0.15 0.66 198 283 3,844 133 133 150 0.00 294.03 45 225 3.75 1.5 0.54 0.35 0.46 0.19 0.82 245 395 3,886 135 135 260 0.01 294.06 46 230 3.83 1.5 0.54 0.35 0.46 0.19 0.82 245 505 3,927 136 136 369 0.01 294.08 47 235 3.92 1.6 0.57 0.35 0.49 0.22 0.97 292 661 3,986 138 138 523 0.01 294.11 48 240 4.00 1.6 0.57 0.35 0.49 0.22 0.97 292 815 4,043 140 140 675 0.02 294.15 49 245 4.08 1.7 0.61 0.35 0.52 0.26 1.13 339 1,014 4,118 143 143 871 0.02 294.19 50 250 4.17 1.8 0.64 0.35 0.55 0.29 1.29 386 1,257 4,209 146 146 1,111 0.03 294.24 Plate E-2.2 6-Hour Storm Page 8 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 4.35 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 2.63 Maxwell Drywells UNIT TIME-PERCENT OF LAG 190.0 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.98 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.35 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft Loss Rate RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 6-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Basin Losses 51 255 4.25 1.9 0.68 0.35 0.58 0.33 1.44 433 1,544 4,317 150 150 1,394 0.03 294.31 52 260 4.33 2.0 0.72 0.35 0.61 0.37 1.60 480 1,874 4,441 154 154 1,720 0.04 294.38 53 265 4.42 2.1 0.75 0.35 0.64 0.40 1.76 527 2,247 4,580 159 159 2,088 0.05 294.46 54 270 4.50 2.1 0.75 0.35 0.64 0.40 1.76 527 2,616 4,718 164 164 2,452 0.06 294.54 55 275 4.58 2.2 0.79 0.35 0.67 0.44 1.91 574 3,026 4,872 169 169 2,857 0.07 294.63 56 280 4.67 2.3 0.82 0.35 0.70 0.47 2.07 621 3,478 5,042 175 175 3,303 0.08 294.72 57 285 4.75 2.4 0.86 0.35 0.73 0.51 2.23 668 3,971 5,227 181 181 3,790 0.09 294.83 58 290 4.83 2.4 0.86 0.35 0.73 0.51 2.23 668 4,458 5,409 188 188 4,270 0.10 294.94 59 295 4.92 2.5 0.89 0.35 0.76 0.54 2.38 715 4,986 5,558 193 193 4,793 0.11 295.04 60 300 5.00 2.6 0.93 0.35 0.79 0.58 2.54 762 5,555 5,706 198 198 5,357 0.12 295.13 61 305 5.08 3.1 1.11 0.35 0.94 0.76 3.32 997 6,354 5,914 205 205 6,149 0.14 295.25 62 310 5.17 3.6 1.29 0.35 1.09 0.94 4.11 1,232 7,381 6,180 215 215 7,166 0.16 295.42 63 315 5.25 3.9 1.39 0.35 1.19 1.04 4.58 1,373 8,540 6,481 225 225 8,315 0.19 295.60 64 320 5.33 4.2 1.50 0.35 1.28 1.15 5.05 1,514 9,829 6,816 237 237 9,592 0.22 295.81 65 325 5.42 4.7 1.68 0.35 1.43 1.33 5.83 1,749 11,342 7,168 249 249 11,093 0.25 296.04 66 330 5.50 5.6 2.00 0.35 1.70 1.65 7.24 2,172 13,265 7,523 261 261 13,004 0.30 296.28 67 335 5.58 1.9 0.68 0.35 0.58 0.33 1.44 433 13,437 7,555 262 262 13,175 0.30 296.30 68 340 5.67 0.9 0.32 0.35 0.27 0.05 0.21 63 13,238 7,518 261 261 12,977 0.30 296.28 69 345 5.75 0.6 0.21 0.35 0.18 0.03 0.14 42 13,019 7,478 260 260 12,760 0.29 296.25 70 350 5.83 0.5 0.18 0.35 0.15 0.03 0.12 35 12,795 7,436 258 258 12,537 0.29 296.22 71 355 5.92 0.3 0.11 0.35 0.09 0.02 0.07 21 12,558 7,393 257 257 12,301 0.28 296.19 72 360 6.00 0.2 0.07 0.35 0.06 0.01 0.05 14 12,315 7,348 255 255 12,060 0.28 296.16 TOTAL RAINFALL RAINFALL VOLUME SOIL LOSSES EFFECTIVE RAIN FLOOD VOLUME FLOOD VOLUME REQUIRED STORAGE REQUIRED STORAGE MAX WSEL PEAK FLOW RATE TOTAL BASIN LOSSES AVERAGE PERCOLATION RATE EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY 22.17 cf/min 7,982 cu-ft 1.27 in 0.46 acft 20,042 cu-ft 0.30 acft 13,175 cu-ft 47,004 cu-ft 2.98 in 26,962 cu-ft 296.30 ft 7.24 cfs Plate E-2.2 6-Hour Storm Page 9 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 4.35 VARIABLE LOSS RATE (AVG) IN/HR Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 15 Fm = Minimum value on loss curve (in/hr)0.17 LAG TIME - MINUTES 2.63 C 0.00324 Maxwell Drywells UNIT TIME-PERCENT OF LAG 570%Low Loss Rate (percent)85.00%Number 0 TOTAL ADJUSTED STORM RAIN (in)4.59 Drywell Percolation Rate 0.00 cfs 0.00 cfm Unit Time Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 15 0.25 0.2 0.037 0.618 0.031 0.01 0.02 22 22 3,746 390 22 0 0.00 294.00 2 30 0.50 0.3 0.055 0.611 0.047 0.01 0.04 33 33 3,750 391 33 0 0.00 294.00 3 45 0.75 0.3 0.055 0.603 0.047 0.01 0.04 33 33 3,750 391 33 0 0.00 294.00 4 60 1.00 0.4 0.073 0.596 0.062 0.01 0.05 43 43 3,754 391 43 0 0.00 294.00 5 75 1.25 0.3 0.055 0.589 0.047 0.01 0.04 33 33 3,750 391 33 0 0.00 294.00 6 90 1.50 0.3 0.055 0.582 0.047 0.01 0.04 33 33 3,750 391 33 0 0.00 294.00 7 105 1.75 0.3 0.055 0.575 0.047 0.01 0.04 33 33 3,750 391 33 0 0.00 294.00 8 120 2.00 0.4 0.073 0.568 0.062 0.01 0.05 43 43 3,754 391 43 0 0.00 294.00 9 135 2.25 0.4 0.073 0.562 0.062 0.01 0.05 43 43 3,754 391 43 0 0.00 294.00 10 150 2.50 0.4 0.073 0.555 0.062 0.01 0.05 43 43 3,754 391 43 0 0.00 294.00 11 165 2.75 0.5 0.092 0.548 0.078 0.01 0.06 54 54 3,758 391 54 0 0.00 294.00 12 180 3.00 0.5 0.092 0.541 0.078 0.01 0.06 54 54 3,758 391 54 0 0.00 294.00 13 195 3.25 0.5 0.092 0.535 0.078 0.01 0.06 54 54 3,758 391 54 0 0.00 294.00 14 210 3.50 0.5 0.092 0.528 0.078 0.01 0.06 54 54 3,758 391 54 0 0.00 294.00 15 225 3.75 0.5 0.092 0.521 0.078 0.01 0.06 54 54 3,758 391 54 0 0.00 294.00 16 240 4.00 0.6 0.110 0.515 0.094 0.02 0.07 65 65 3,762 392 65 0 0.00 294.00 17 255 4.25 0.6 0.110 0.508 0.094 0.02 0.07 65 65 3,762 392 65 0 0.00 294.00 18 270 4.50 0.7 0.129 0.502 0.109 0.02 0.08 76 76 3,766 392 76 0 0.00 294.00 19 285 4.75 0.7 0.129 0.495 0.109 0.02 0.08 76 76 3,766 392 76 0 0.00 294.00 20 300 5.00 0.8 0.147 0.489 0.125 0.02 0.10 87 87 3,771 393 87 0 0.00 294.00 21 315 5.25 0.6 0.110 0.483 0.094 0.02 0.07 65 65 3,762 392 65 0 0.00 294.00 22 330 5.50 0.7 0.129 0.476 0.109 0.02 0.08 76 76 3,766 392 76 0 0.00 294.00 23 345 5.75 0.8 0.147 0.470 0.125 0.02 0.10 87 87 3,771 393 87 0 0.00 294.00 24 360 6.00 0.8 0.147 0.464 0.125 0.02 0.10 87 87 3,771 393 87 0 0.00 294.00 25 375 6.25 0.9 0.165 0.458 0.140 0.02 0.11 98 98 3,775 393 98 0 0.00 294.00 26 390 6.50 0.9 0.165 0.452 0.140 0.02 0.11 98 98 3,775 393 98 0 0.00 294.00 27 405 6.75 1.0 0.184 0.446 0.156 0.03 0.12 109 109 3,779 394 109 0 0.00 294.00 28 420 7.00 1.0 0.184 0.440 0.156 0.03 0.12 109 109 3,779 394 109 0 0.00 294.00 29 435 7.25 1.0 0.184 0.434 0.156 0.03 0.12 109 109 3,779 394 109 0 0.00 294.00 30 450 7.50 1.1 0.202 0.428 0.172 0.03 0.13 119 119 3,783 394 119 0 0.00 294.00 31 465 7.75 1.2 0.220 0.422 0.187 0.03 0.14 130 130 3,787 394 130 0 0.00 294.00 32 480 8.00 1.3 0.239 0.416 0.203 0.04 0.16 141 141 3,791 395 141 0 0.00 294.00 33 495 8.25 1.5 0.275 0.410 0.234 0.04 0.18 163 163 3,799 396 163 0 0.00 294.00 34 510 8.50 1.5 0.275 0.404 0.234 0.04 0.18 163 163 3,799 396 163 0 0.00 294.00 35 525 8.75 1.6 0.294 0.399 0.250 0.04 0.19 174 174 3,803 396 174 0 0.00 294.00 36 540 9.00 1.7 0.312 0.393 0.265 0.05 0.21 185 185 3,807 397 185 0 0.00 294.00 37 555 9.25 1.9 0.349 0.388 0.297 0.05 0.23 206 206 3,815 397 206 0 0.00 294.00 38 570 9.50 2.0 0.367 0.382 0.312 0.06 0.24 217 217 3,819 398 217 0 0.00 294.00 39 585 9.75 2.1 0.386 0.377 0.328 0.01 0.04 35 35 3,751 391 35 0 0.00 294.00 40 600 10.00 2.2 0.404 0.371 0.343 0.03 0.14 129 129 3,786 394 129 0 0.00 294.00 41 615 10.25 1.5 0.275 0.366 0.234 0.04 0.18 163 163 3,799 396 163 0 0.00 294.00 42 630 10.50 1.5 0.275 0.361 0.234 0.04 0.18 163 163 3,799 396 163 0 0.00 294.00 43 645 10.75 2.0 0.367 0.355 0.312 0.01 0.05 47 47 3,756 391 47 0 0.00 294.00 in/hr Total In Basin UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Loss Rate Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD MANUAL 24-HOUR STORM Basin Losses Plate E-2.2 24-Hour Storm Page 10 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 4.35 VARIABLE LOSS RATE (AVG) IN/HR Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 15 Fm = Minimum value on loss curve (in/hr)0.17 LAG TIME - MINUTES 2.63 C 0.00324 Maxwell Drywells UNIT TIME-PERCENT OF LAG 570%Low Loss Rate (percent)85.00%Number 0 TOTAL ADJUSTED STORM RAIN (in)4.59 Drywell Percolation Rate 0.00 cfs 0.00 cfm Unit Time Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft in/hr Total In Basin UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Loss Rate Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD MANUAL 24-HOUR STORM Basin Losses 44 660 11.00 2.0 0.367 0.350 0.312 0.02 0.07 67 67 3,763 392 67 0 0.00 294.00 45 675 11.25 1.9 0.349 0.345 0.297 0.00 0.02 15 15 3,744 390 15 0 0.00 294.00 46 690 11.50 1.9 0.349 0.340 0.297 0.01 0.04 35 35 3,751 391 35 0 0.00 294.00 47 705 11.75 1.7 0.312 0.335 0.265 0.05 0.21 185 185 3,807 397 185 0 0.00 294.00 48 720 12.00 1.8 0.330 0.330 0.281 0.00 0.00 2 2 3,739 389 2 0 0.00 294.00 49 735 12.25 2.5 0.459 0.325 0.390 0.13 0.59 529 529 3,936 410 410 119 0.00 294.03 50 750 12.50 2.6 0.477 0.320 0.406 0.16 0.69 620 739 4,015 418 418 321 0.01 294.07 51 765 12.75 2.8 0.514 0.315 0.437 0.20 0.87 784 1,105 4,152 433 433 672 0.02 294.15 52 780 13.00 2.9 0.532 0.311 0.453 0.22 0.97 875 1,547 4,318 450 450 1,097 0.03 294.24 53 795 13.25 3.4 0.624 0.306 0.531 0.32 1.40 1,256 2,353 4,620 481 481 1,872 0.04 294.41 54 810 13.50 3.4 0.624 0.301 0.531 0.32 1.42 1,274 3,146 4,917 512 512 2,634 0.06 294.58 55 825 13.75 2.3 0.422 0.297 0.359 0.13 0.55 496 3,129 4,911 512 512 2,618 0.06 294.57 56 840 14.00 2.3 0.422 0.292 0.359 0.13 0.57 513 3,131 4,912 512 512 2,619 0.06 294.57 57 855 14.25 2.7 0.496 0.288 0.421 0.21 0.91 821 3,440 5,027 524 524 2,916 0.07 294.64 58 870 14.50 2.6 0.477 0.283 0.406 0.19 0.85 765 3,682 5,118 533 533 3,149 0.07 294.69 59 885 14.75 2.6 0.477 0.279 0.406 0.20 0.87 783 3,931 5,211 543 543 3,388 0.08 294.74 60 900 15.00 2.5 0.459 0.275 0.390 0.18 0.81 727 4,115 5,280 550 550 3,565 0.08 294.78 61 915 15.25 2.4 0.441 0.270 0.375 0.17 0.75 671 4,236 5,326 555 555 3,681 0.08 294.81 62 930 15.50 2.3 0.422 0.266 0.359 0.16 0.68 615 4,297 5,348 557 557 3,739 0.09 294.82 63 945 15.75 1.9 0.349 0.262 0.297 0.09 0.38 342 4,081 5,268 549 549 3,532 0.08 294.77 64 960 16.00 1.9 0.349 0.258 0.297 0.09 0.40 357 3,890 5,196 541 541 3,348 0.08 294.73 65 975 16.25 0.4 0.073 0.254 0.062 0.01 0.05 43 3,392 5,009 522 522 2,870 0.07 294.63 66 990 16.50 0.4 0.073 0.250 0.062 0.01 0.05 43 2,913 4,830 503 503 2,410 0.06 294.53 67 1005 16.75 0.3 0.055 0.247 0.047 0.01 0.04 33 2,443 4,654 485 485 1,958 0.04 294.43 68 1020 17.00 0.3 0.055 0.243 0.047 0.01 0.04 33 1,991 4,484 467 467 1,524 0.03 294.33 69 1035 17.25 0.5 0.092 0.239 0.078 0.01 0.06 54 1,578 4,329 451 451 1,127 0.03 294.25 70 1050 17.50 0.5 0.092 0.236 0.078 0.01 0.06 54 1,181 4,181 435 435 746 0.02 294.16 71 1065 17.75 0.5 0.092 0.232 0.078 0.01 0.06 54 800 4,038 421 421 379 0.01 294.08 72 1080 18.00 0.4 0.073 0.229 0.062 0.01 0.05 43 423 3,896 406 406 17 0.00 294.00 73 1095 18.25 0.4 0.073 0.225 0.062 0.01 0.05 43 60 3,761 392 60 0 0.00 294.00 74 1110 18.50 0.4 0.073 0.222 0.062 0.01 0.05 43 43 3,754 391 43 0 0.00 294.00 75 1125 18.75 0.3 0.055 0.219 0.047 0.01 0.04 33 33 3,750 391 33 0 0.00 294.00 76 1140 19.00 0.2 0.037 0.216 0.031 0.01 0.02 22 22 3,746 390 22 0 0.00 294.00 77 1155 19.25 0.3 0.055 0.213 0.047 0.01 0.04 33 33 3,750 391 33 0 0.00 294.00 78 1170 19.50 0.4 0.073 0.210 0.062 0.01 0.05 43 43 3,754 391 43 0 0.00 294.00 79 1185 19.75 0.3 0.055 0.207 0.047 0.01 0.04 33 33 3,750 391 33 0 0.00 294.00 80 1200 20.00 0.2 0.037 0.204 0.031 0.01 0.02 22 22 3,746 390 22 0 0.00 294.00 81 1215 20.25 0.3 0.055 0.201 0.047 0.01 0.04 33 33 3,750 391 33 0 0.00 294.00 82 1230 20.50 0.3 0.055 0.199 0.047 0.01 0.04 33 33 3,750 391 33 0 0.00 294.00 83 1245 20.75 0.3 0.055 0.196 0.047 0.01 0.04 33 33 3,750 391 33 0 0.00 294.00 84 1260 21.00 0.2 0.037 0.194 0.031 0.01 0.02 22 22 3,746 390 22 0 0.00 294.00 85 1275 21.25 0.3 0.055 0.192 0.047 0.01 0.04 33 33 3,750 391 33 0 0.00 294.00 86 1290 21.50 0.2 0.037 0.189 0.031 0.01 0.02 22 22 3,746 390 22 0 0.00 294.00 Plate E-2.2 24-Hour Storm Page 11 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 4.35 VARIABLE LOSS RATE (AVG) IN/HR Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 15 Fm = Minimum value on loss curve (in/hr)0.17 LAG TIME - MINUTES 2.63 C 0.00324 Maxwell Drywells UNIT TIME-PERCENT OF LAG 570%Low Loss Rate (percent)85.00%Number 0 TOTAL ADJUSTED STORM RAIN (in)4.59 Drywell Percolation Rate 0.00 cfs 0.00 cfm Unit Time Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft in/hr Total In Basin UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Loss Rate Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD MANUAL 24-HOUR STORM Basin Losses 87 1305 21.75 0.3 0.055 0.187 0.047 0.01 0.04 33 33 3,750 391 33 0 0.00 294.00 88 1320 22.00 0.2 0.037 0.185 0.031 0.01 0.02 22 22 3,746 390 22 0 0.00 294.00 89 1335 22.25 0.3 0.055 0.184 0.047 0.01 0.04 33 33 3,750 391 33 0 0.00 294.00 90 1350 22.50 0.2 0.037 0.182 0.031 0.01 0.02 22 22 3,746 390 22 0 0.00 294.00 91 1365 22.75 0.2 0.037 0.180 0.031 0.01 0.02 22 22 3,746 390 22 0 0.00 294.00 92 1380 23.00 0.2 0.037 0.179 0.031 0.01 0.02 22 22 3,746 390 22 0 0.00 294.00 93 1395 23.25 0.2 0.037 0.178 0.031 0.01 0.02 22 22 3,746 390 22 0 0.00 294.00 94 1410 23.50 0.2 0.037 0.176 0.031 0.01 0.02 22 22 3,746 390 22 0 0.00 294.00 95 1425 23.75 0.2 0.037 0.176 0.031 0.01 0.02 22 22 3,746 390 22 0 0.00 294.00 96 1440 24.00 0.2 0.037 0.175 0.031 0.01 0.02 22 22 3,746 390 22 0 0.00 294.00 EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY TOTAL RAINFALL RAINFALL VOLUME SOIL LOSSES EFFECTIVE RAIN FLOOD VOLUME FLOOD VOLUME REQUIRED STORAGE REQUIRED STORAGE MAX WSEL PEAK FLOW RATE TOTAL BASIN LOSSES AVERAGE PERCOLATION RATE 16,645 cu-ft 11.56 cf/min 1.06 in 0.38 acft 16,645 cu-ft 0.09 acft 3,739 cu-ft 4.59 in 72,399 cu-ft 55,753 cu-ft 294.82 ft 1.42 cfs Plate E-2.2 24-Hour Storm Page 12 of 13 PROECT JOB No. BASIN DESIGNATION: BASIN CHARACTERISTICS CONTOUR ELEVATION INCR TOTAL INCR TOTAL INCR (ft)(ft)(sf)(sf)(cuft)(cuft)(acre-ft) 294 0 0 3,738 0 0 0.00 295 1 1 1,712 5,450 4,567 4,567 0.10 296 1 2 1,620 7,070 6,242 10,809 0.25 297 1 3 1,435 8,505 7,776 18,586 0.43 298 1 4 1,523 10,028 9,256 27,842 0.64 WHERE: TOTAL Retention Basin- D BASIN VOLUME WORKSHEET DEPTH AREA VOLUME Del Webb Explore at Palm Desert 2636 ()()2121213 1 AAAAEEV++−= Basin Volume Worksheet Page 13 of 13 FOS 2 AMC II AREA SOIL TRIBUTARY AREAS ACRES LOW LOSS RI INFILTRATION IMPERVIOUS DESIG GROUP CONDITION NUMBER RATE PERCENT 4 A SF - DETACHED 5.259 D 32 0.74 0.50 9 A LANDSCAPING 0.995 D 32 0.74 0.10 2 A PAVING/HARDSCAPE 2.155 D 32 0.74 1.00 1 A RECREATION CENTER 2.185 D 32 0.74 0.60 803 ft 402 ft 308.3 ft ELEVATION OF CONCENTRATION POINT 300.0 ft 0.02 100 LOW LOSS RATE (Storm Events > 10 Years)85% POINT RAIN FROM NOAA ATLAS 14 1-HOUR 1.57 in 3-HOUR 2.27 in 6-HOUR 2.98 in 24-HOUR 4.59 in BASIN CHARACTERISTICS:ELEVATION AREA 291.2 ft 17,560 sf 292.0 ft 19,127 sf 293.0 ft 21,142 sf 294.0 ft 23,225 sf 295.0 ft 25,369 sf PERCOLATION RATE (in/hr)5.0 in/hr DRYWELL DATA NUMBER USED 50 PERCOLATION RATE LOWEST FLOWLINE ELEVATION 299.96 LOWEST PAD ELEVATION 301.7 LENGTH OF WATERCOURSE (L) AREA DESIGNATION ELEVATION OF HEADWATER AVERAGE MANNINGS 'N' VALUE STORM FREQUENCY (YEAR) LENGTH TO POINT OPPOSITE CENTROID (Lca) Low Loss Conditions: X=Existing; D=Developed; BS=Retention DA-E RCFCD SYNTHETIC UNIT HYDROGRAPH - SHORTCUT METHOD DATA INPUT SHEET WORKSHEET PREPARED BY: PROJECT NAME DATE January 9, 2024 Del Webb Explore at Palm Desert PROJECT NUMBER CONCENTRATION POINT DESIGNATION 2636 Retention Basin E AMC NUMBER Data Input Sheet Page 1 of 13 PROJECT: Job No.: BY:DATE:1/9/24 [1] AMC II [2] FREQUENCY-YEARS 100 FROM NOAA ATLAS 14 [3] STORM DURATION:Point Rain 1-HOUR 1.57 in 3-HOUR 2.27 in 6-HOUR 2.98 in 24-HOUR 4.59 in STORM DURATION 1-HOUR 3-HOUR 6-HOUR 24-HOUR RAINFALL VOLUME (cu-ft)60,371 87,289 114,590 176,500 SOIL LOSSES (cu-ft)13,479 39,453 65,808 135,580 EFFECTIVE RAIN (in)1.22 1.24 1.27 1.06 FLOOD VOLUME (cu-ft)46,892 47,836 48,782 40,920 (acre-ft)1.08 1.10 1.12 0.94 REQUIRED STORAGE (cu-ft)38,942 30,408 27,289 2,737 (acre-ft)0.89 0.70 0.63 0.06 FACTOR OF SAFETY 2.09 2.67 2.98 29.69 STORAGE PROVIDED (cu-ft) (acre-ft) PEAK FLOW (cfs)n/a 20.11 17.65 3.44 MAXIMUM WSEL (ft)293.19 292.78 292.63 291.35 DEPTH (ft)1.99 1.58 1.43 0.15 DIFFERENCE (ft)6.77 7.18 7.33 8.61 DIFFERENCE (ft)8.51 8.92 9.07 10.35 ESTIMATED TIME TO DEWATER BASIN Based on Total Flood Volume & Average Percolation Rate (days)0.2 0.3 0.5 1.0 [18] 200% OF LAG-MINUTES RAINFALL DATA 4.9 NOTE: PEAK FLOW FOR THE 1-HOUR STORM IS NOT REPRESENTATIVE. PER RCFCD PEAK DISCHARGES FROM THE 3-HOUR STORM SHOULD NORMALLY COMPARE WELL WITH RATIONAL PEAKS. LOWEST PAD ELEVATION LOWEST FLOWLINE ELEVATION STORM EVENT SUMMARY 301.7 299.96 81,261 1.87 0.02 [17] 100% OF LAG-MINUTES 2.5 2.5 [14] AVERAGE MANNINGS 'N' [15] LAG TIME-HOURS 0.04 [16] LAG TIME-MINUTES [13] L*LCA/S^0.5 7.41 [11] S-FEET/MILE [6] La-FEET [7] La-MILES [8] ELEVATION OF HEADWATER 0.002 401.50 [12] S^0.5 0.076 54.8 308.3 299.96 8.34 [3] AREA - ACRES [4] L-FEET [5] L-MILES 803 0.152 Retention Basin E DA-E Del Webb Explore at Palm Desert [10] H-FEET [9] ELEVATION OF CONCENTRATION POINT 10.593 PHYSICAL DATA [1] CONCENTRATION POINT HYDROLOGY MANUAL BASIC DATA CALCULATION FORM 2636 FOS RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD [2] AREA DESIGNATION Plate E-2.1 Page 2 of 13 PROJECT: Job No.: BY:DATE:1/9/24 MAX LOW LOW MIN SOIL RI PERVIOUS DECIMAL ADJUSTED AREA AREA AVERAGE LOSS LOSS RATE AVERAGE GROUP NUMBER AREA PERCENT INFILTRATION WEIGHTED ADJUSTED CONDITION PER ADJUSTED INFILTRATION OF AREA RATE AVERAGE INFILTRATION RCFC/2322 INFILTRATION RATE IMPERVIOUS RATE RATE (in/hr)(in/hr)(in/hr) [Plate C-1][Plate E-6.1][Plate E-6.2][Plate E-6.3] A 32 0.74 50%0.41 5.259 0.496 0.2021 DEVELOPED 0.5000 0.2482 A 32 0.74 10%0.67 0.995 0.094 0.0632 DEVELOPED 0.8200 0.0770 A 32 0.74 100%0.07 2.155 0.203 0.0151 DEVELOPED 0.1000 0.0203 A 32 0.74 60%0.34 2.185 0.206 0.0702 DEVELOPED 0.4200 0.0866 SUM 10.593 SUM 0.3505 0.4322 VARIABLE LOSS RATE CURVE (24-HOUR STORM ONLY) Fm=0.175270555 NOTE: Low loss rates established per RCFC/2322 (Dated: May-30-95) C=0.00325 For 10 Year Storms or Less Ft=C(24-(T/60))^1.55+Fm =0.00325 0.18 in/hr Undeveloped Condition: Low Loss = 90% CONSTANT LOSS RATE (3 & 6 HOUR STORMS)=0.3505 Developed Condition: Low Loss = 0.9 - (0.8 * %impervious) LOW LOSS RATE =0.8500 Basin Site: Low Loss = 10% Where:For 100 Year Storm - Low Loss should be between 80% & 90% T=Time in minutes. To get an average value for each unit time period, Use T=1/2 the unit time for the first time period,of the Rainfall Rate T=1 1/2 unit time for the second period, etc. (24-(T/60))^1.55 + LAND USE SF - DETACHED LANDSCAPING PAVING/HARDSCAPE RECREATION CENTER AVERAGE ADJUSTED LOSS RATE RCFC & WCD HYDROLOGY MANUAL SYNTHETIC UNIT HYDROGRAPH METHOD BASIC DATA CALCULATION FORM Del Webb Explore at Palm Desert FOS 2636 AMC II Plate E-2.1 Page 3 of 13 PROJECT: Job No.:2636 BY:FOS DATE 1/9/24 DRAINAGE AREA-ACRES 10.59 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 2.47 Maxwell Drywells UNIT TIME-PERCENT OF LAG 202.3 Number 50 TOTAL ADJUSTED STORM RAIN-INCHES 1.57 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE-in/hr 0.35 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 5 0.08 3.6 0.68 0.35 0.58 0.33 3.50 1,050 1,050 17,672 614 614 436 0.01 291.22 2 10 0.17 4.2 0.79 0.35 0.67 0.44 4.71 1,412 1,849 17,757 617 617 1,232 0.03 291.27 3 15 0.25 4.4 0.83 0.35 0.70 0.48 5.11 1,533 2,765 17,855 620 620 2,145 0.05 291.32 4 20 0.33 4.6 0.87 0.35 0.74 0.52 5.51 1,654 3,799 17,966 624 624 3,175 0.07 291.37 5 25 0.42 5.0 0.94 0.35 0.80 0.59 6.32 1,895 5,071 18,102 629 629 4,442 0.10 291.44 6 30 0.50 5.6 1.06 0.35 0.90 0.70 7.53 2,258 6,700 18,276 635 635 6,065 0.14 291.53 7 35 0.58 6.4 1.21 0.35 1.02 0.86 9.13 2,740 8,805 18,501 642 642 8,163 0.19 291.65 8 40 0.67 8.1 1.53 0.35 1.30 1.18 12.56 3,767 11,930 18,834 654 654 11,276 0.26 291.81 9 45 0.75 13.1 2.47 0.35 2.10 2.12 22.62 6,785 18,061 19,466 676 676 17,385 0.40 292.13 10 50 0.83 34.5 6.50 0.35 5.52 6.15 65.68 19,705 37,090 21,357 742 742 36,349 0.83 293.07 11 55 0.92 6.7 1.26 0.35 1.07 0.91 9.74 2,922 39,270 21,562 749 749 38,522 0.88 293.17 12 60 1.00 3.8 0.72 0.35 0.61 0.37 3.90 1,171 39,692 21,602 750 750 38,942 0.89 293.19 TOTAL RAINFALL 1.57 in RAINFALL VOLUME 60,371 cu-ft SOIL LOSSES 13,479 cu-ft EFFECTIVE RAIN 1.22 in FLOOD VOLUME 1.08 acft FLOOD VOLUME 46,892 cu-ft REQUIRED STORAGE 0.89 REQUIRED STORAGE 38,942 cu-ft MAX WSEL 293.19 ft PEAK FLOW RATE 65.68 cfs TOTAL BASIN LOSSES 7,950 cu-ft AVERAGE PERCOLATION RATE 132.49 cf/min EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Total In Basin in/hr Time Loss Rate Basin Losses Del Webb Explore at Palm DesertRCFC & WCD HYDROLOGY MANUAL SYNTHETIC UNIT HYDROGRAPH METHOD SHORTCUT METHOD 1-HOUR STORM Plate E-2.2 1-Hour Storm Page 4 of 13 PROJECT: Job No.:2636 BY:FOS DATE DRAINAGE AREA-ACRES 10.59 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 2.47 Maxwell Drywells UNIT TIME-PERCENT OF LAG 202.3 Number 50 TOTAL ADJUSTED STORM RAIN (in)2.27 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.35 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 5 0.08 1.3 0.35 0.35 0.30 0.00 0.04 11 11 17,561 610 11 0 0.00 291.20 2 10 0.17 1.3 0.35 0.35 0.30 0.00 0.04 11 11 17,561 610 11 0 0.00 291.20 3 15 0.25 1.1 0.30 0.35 0.25 0.04 0.48 144 144 17,575 610 144 0 0.00 291.20 4 20 0.33 1.5 0.41 0.35 0.35 0.06 0.62 186 186 17,580 610 186 0 0.00 291.20 5 25 0.42 1.5 0.41 0.35 0.35 0.06 0.62 186 186 17,580 610 186 0 0.00 291.20 6 30 0.50 1.8 0.49 0.35 0.42 0.14 1.49 448 448 17,608 611 448 0 0.00 291.20 7 35 0.58 1.5 0.41 0.35 0.35 0.06 0.62 186 186 17,580 610 186 0 0.00 291.20 8 40 0.67 1.8 0.49 0.35 0.42 0.14 1.49 448 448 17,608 611 448 0 0.00 291.20 9 45 0.75 1.8 0.49 0.35 0.42 0.14 1.49 448 448 17,608 611 448 0 0.00 291.20 10 50 0.83 1.5 0.41 0.35 0.35 0.06 0.62 186 186 17,580 610 186 0 0.00 291.20 11 55 0.92 1.6 0.44 0.35 0.37 0.09 0.91 273 273 17,589 611 273 0 0.00 291.20 12 60 1.00 1.8 0.49 0.35 0.42 0.14 1.49 448 448 17,608 611 448 0 0.00 291.20 13 65 1.08 2.2 0.60 0.35 0.51 0.25 2.66 797 797 17,645 613 613 184 0.00 291.21 14 70 1.17 2.2 0.60 0.35 0.51 0.25 2.66 797 981 17,665 613 613 368 0.01 291.22 15 75 1.25 2.2 0.60 0.35 0.51 0.25 2.66 797 1,165 17,684 614 614 551 0.01 291.23 16 80 1.33 2.0 0.54 0.35 0.46 0.19 2.07 622 1,174 17,685 614 614 560 0.01 291.23 17 85 1.42 2.6 0.71 0.35 0.60 0.36 3.82 1,146 1,706 17,742 616 616 1,090 0.03 291.26 18 90 1.50 2.7 0.74 0.35 0.63 0.38 4.11 1,234 2,323 17,808 618 618 1,705 0.04 291.29 19 95 1.58 2.4 0.65 0.35 0.56 0.30 3.24 972 2,677 17,846 620 620 2,057 0.05 291.31 20 100 1.67 2.7 0.74 0.35 0.63 0.38 4.11 1,234 3,290 17,911 622 622 2,668 0.06 291.35 21 105 1.75 3.3 0.90 0.35 0.76 0.55 5.86 1,757 4,426 18,033 626 626 3,800 0.09 291.41 22 110 1.83 3.1 0.84 0.35 0.72 0.49 5.28 1,583 5,382 18,135 630 630 4,753 0.11 291.46 23 115 1.92 2.9 0.79 0.35 0.67 0.44 4.69 1,408 6,161 18,218 633 633 5,528 0.13 291.50 24 120 2.00 3.0 0.82 0.35 0.69 0.47 4.98 1,495 7,023 18,310 636 636 6,388 0.15 291.55 25 125 2.08 3.1 0.84 0.35 0.72 0.49 5.28 1,583 7,970 18,411 639 639 7,331 0.17 291.60 RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 3-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Loss Rate Basin Losses Plate E-2.2 3-Hour Storm Page 5 of 13 PROJECT: Job No.:2636 BY:FOS DATE DRAINAGE AREA-ACRES 10.59 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 2.47 Maxwell Drywells UNIT TIME-PERCENT OF LAG 202.3 Number 50 TOTAL ADJUSTED STORM RAIN (in)2.27 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.35 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 3-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Loss Rate Basin Losses 26 130 2.17 4.2 1.14 0.35 0.97 0.79 8.48 2,543 9,874 18,615 646 646 9,228 0.21 291.70 27 135 2.25 5.0 1.36 0.35 1.16 1.01 10.80 3,241 12,469 18,892 656 656 11,813 0.27 291.84 28 140 2.33 3.5 0.95 0.35 0.81 0.60 6.44 1,932 13,745 19,028 661 661 13,084 0.30 291.91 29 145 2.42 6.8 1.85 0.35 1.57 1.50 16.04 4,812 17,896 19,450 675 675 17,221 0.40 292.13 30 150 2.50 7.3 1.99 0.35 1.69 1.64 17.50 5,249 22,470 19,908 691 691 21,778 0.50 292.35 31 155 2.58 8.2 2.23 0.35 1.90 1.88 20.11 6,034 27,813 20,443 710 710 27,103 0.62 292.62 32 160 2.67 5.9 1.61 0.35 1.37 1.26 13.42 4,027 31,130 20,775 721 721 30,408 0.70 292.78 33 165 2.75 2.0 0.54 0.35 0.46 0.19 2.07 622 31,031 20,765 721 721 30,310 0.70 292.78 34 170 2.83 1.8 0.49 0.35 0.42 0.14 1.49 448 30,758 20,738 720 720 30,038 0.69 292.76 35 175 2.92 1.8 0.49 0.35 0.42 0.14 1.49 448 30,486 20,710 719 719 29,766 0.68 292.75 36 180 3.00 0.6 0.16 0.35 0.14 0.02 0.26 79 29,845 20,646 717 717 29,128 0.67 292.72 TOTAL RAIN RAINFALL VOLUME SOIL LOSSES EFFECTIVE RAIN FLOOD VOLUME FLOOD VOLUME REQUIRED STORAGE REQUIRED STORAGE MAX WSEL PEAK FLOW RATE TOTAL BASIN LOSSES AVERAGE PERCOLATION RATE EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY 18,708 cu-ft 103.93 cf/min 1.24 in 1.10 acft 47,836 cu-ft 0.70 acft 30,408 cu-ft 39,453 cu-ft 2.27 in 87,289 cu-ft 292.78 ft 20.11 cfs Plate E-2.2 3-Hour Storm Page 6 of 13 PROJECT: Job No.:2636 BY:FOS DATE 1/9/24 DRAINAGE AREA-ACRES 10.59 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 2.47 Maxwell Drywells UNIT TIME-PERCENT OF LAG 202.3 Number 50 TOTAL ADJUSTED STORM RAIN (in)2.98 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.35 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 5 0.08 0.5 0.18 0.35 0.15 0.03 0.29 86 86 17,569 610 86 0 0.00 291.20 2 10 0.17 0.6 0.21 0.35 0.18 0.03 0.34 103 103 17,571 610 103 0 0.00 291.20 3 15 0.25 0.6 0.21 0.35 0.18 0.03 0.34 103 103 17,571 610 103 0 0.00 291.20 4 20 0.33 0.6 0.21 0.35 0.18 0.03 0.34 103 103 17,571 610 103 0 0.00 291.20 5 25 0.42 0.6 0.21 0.35 0.18 0.03 0.34 103 103 17,571 610 103 0 0.00 291.20 6 30 0.50 0.7 0.25 0.35 0.21 0.04 0.40 120 120 17,573 610 120 0 0.00 291.20 7 35 0.58 0.7 0.25 0.35 0.21 0.04 0.40 120 120 17,573 610 120 0 0.00 291.20 8 40 0.67 0.7 0.25 0.35 0.21 0.04 0.40 120 120 17,573 610 120 0 0.00 291.20 9 45 0.75 0.7 0.25 0.35 0.21 0.04 0.40 120 120 17,573 610 120 0 0.00 291.20 10 50 0.83 0.7 0.25 0.35 0.21 0.04 0.40 120 120 17,573 610 120 0 0.00 291.20 11 55 0.92 0.7 0.25 0.35 0.21 0.04 0.40 120 120 17,573 610 120 0 0.00 291.20 12 60 1.00 0.8 0.29 0.35 0.24 0.04 0.46 138 138 17,575 610 138 0 0.00 291.20 13 65 1.08 0.8 0.29 0.35 0.24 0.04 0.46 138 138 17,575 610 138 0 0.00 291.20 14 70 1.17 0.8 0.29 0.35 0.24 0.04 0.46 138 138 17,575 610 138 0 0.00 291.20 15 75 1.25 0.8 0.29 0.35 0.24 0.04 0.46 138 138 17,575 610 138 0 0.00 291.20 16 80 1.33 0.8 0.29 0.35 0.24 0.04 0.46 138 138 17,575 610 138 0 0.00 291.20 17 85 1.42 0.8 0.29 0.35 0.24 0.04 0.46 138 138 17,575 610 138 0 0.00 291.20 18 90 1.50 0.8 0.29 0.35 0.24 0.04 0.46 138 138 17,575 610 138 0 0.00 291.20 19 95 1.58 0.8 0.29 0.35 0.24 0.04 0.46 138 138 17,575 610 138 0 0.00 291.20 20 100 1.67 0.8 0.29 0.35 0.24 0.04 0.46 138 138 17,575 610 138 0 0.00 291.20 21 105 1.75 0.8 0.29 0.35 0.24 0.04 0.46 138 138 17,575 610 138 0 0.00 291.20 22 110 1.83 0.8 0.29 0.35 0.24 0.04 0.46 138 138 17,575 610 138 0 0.00 291.20 23 115 1.92 0.8 0.29 0.35 0.24 0.04 0.46 138 138 17,575 610 138 0 0.00 291.20 24 120 2.00 0.9 0.32 0.35 0.27 0.05 0.52 155 155 17,577 610 155 0 0.00 291.20 Loss Rate RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 6-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Basin Losses Plate E-2.2 6-Hour Storm Page 7 of 13 PROJECT: Job No.:2636 BY:FOS DATE 1/9/24 DRAINAGE AREA-ACRES 10.59 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 2.47 Maxwell Drywells UNIT TIME-PERCENT OF LAG 202.3 Number 50 TOTAL ADJUSTED STORM RAIN (in)2.98 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.35 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft Loss Rate RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 6-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Basin Losses 25 125 2.08 0.8 0.29 0.35 0.24 0.04 0.46 138 138 17,575 610 138 0 0.00 291.20 26 130 2.17 0.9 0.32 0.35 0.27 0.05 0.52 155 155 17,577 610 155 0 0.00 291.20 27 135 2.25 0.9 0.32 0.35 0.27 0.05 0.52 155 155 17,577 610 155 0 0.00 291.20 28 140 2.33 0.9 0.32 0.35 0.27 0.05 0.52 155 155 17,577 610 155 0 0.00 291.20 29 145 2.42 0.9 0.32 0.35 0.27 0.05 0.52 155 155 17,577 610 155 0 0.00 291.20 30 150 2.50 0.9 0.32 0.35 0.27 0.05 0.52 155 155 17,577 610 155 0 0.00 291.20 31 155 2.58 0.9 0.32 0.35 0.27 0.05 0.52 155 155 17,577 610 155 0 0.00 291.20 32 160 2.67 0.9 0.32 0.35 0.27 0.05 0.52 155 155 17,577 610 155 0 0.00 291.20 33 165 2.75 1.0 0.36 0.35 0.30 0.01 0.08 23 23 17,562 610 23 0 0.00 291.20 34 170 2.83 1.0 0.36 0.35 0.30 0.01 0.08 23 23 17,562 610 23 0 0.00 291.20 35 175 2.92 1.0 0.36 0.35 0.30 0.01 0.08 23 23 17,562 610 23 0 0.00 291.20 36 180 3.00 1.0 0.36 0.35 0.30 0.01 0.08 23 23 17,562 610 23 0 0.00 291.20 37 185 3.08 1.0 0.36 0.35 0.30 0.01 0.08 23 23 17,562 610 23 0 0.00 291.20 38 190 3.17 1.1 0.39 0.35 0.33 0.04 0.46 137 137 17,575 610 137 0 0.00 291.20 39 195 3.25 1.1 0.39 0.35 0.33 0.04 0.46 137 137 17,575 610 137 0 0.00 291.20 40 200 3.33 1.1 0.39 0.35 0.33 0.04 0.46 137 137 17,575 610 137 0 0.00 291.20 41 205 3.42 1.2 0.43 0.35 0.36 0.08 0.84 252 252 17,587 611 252 0 0.00 291.20 42 210 3.50 1.3 0.46 0.35 0.40 0.11 1.22 366 366 17,599 611 366 0 0.00 291.20 43 215 3.58 1.4 0.50 0.35 0.43 0.15 1.60 481 481 17,611 612 481 0 0.00 291.20 44 220 3.67 1.4 0.50 0.35 0.43 0.15 1.60 481 481 17,611 612 481 0 0.00 291.20 45 225 3.75 1.5 0.54 0.35 0.46 0.19 1.99 596 596 17,624 612 596 0 0.00 291.20 46 230 3.83 1.5 0.54 0.35 0.46 0.19 1.99 596 596 17,624 612 596 0 0.00 291.20 47 235 3.92 1.6 0.57 0.35 0.49 0.22 2.37 710 710 17,636 612 612 98 0.00 291.21 48 240 4.00 1.6 0.57 0.35 0.49 0.22 2.37 710 808 17,646 613 613 195 0.00 291.21 49 245 4.08 1.7 0.61 0.35 0.52 0.26 2.75 825 1,020 17,669 614 614 406 0.01 291.22 50 250 4.17 1.8 0.64 0.35 0.55 0.29 3.13 939 1,346 17,704 615 615 731 0.02 291.24 Plate E-2.2 6-Hour Storm Page 8 of 13 PROJECT: Job No.:2636 BY:FOS DATE 1/9/24 DRAINAGE AREA-ACRES 10.59 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 2.47 Maxwell Drywells UNIT TIME-PERCENT OF LAG 202.3 Number 50 TOTAL ADJUSTED STORM RAIN (in)2.98 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.35 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft Loss Rate RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 6-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Basin Losses 51 255 4.25 1.9 0.68 0.35 0.58 0.33 3.51 1,054 1,785 17,751 616 616 1,169 0.03 291.26 52 260 4.33 2.0 0.72 0.35 0.61 0.36 3.90 1,169 2,337 17,810 618 618 1,719 0.04 291.29 53 265 4.42 2.1 0.75 0.35 0.64 0.40 4.28 1,283 3,002 17,881 621 621 2,381 0.05 291.33 54 270 4.50 2.1 0.75 0.35 0.64 0.40 4.28 1,283 3,664 17,951 623 623 3,041 0.07 291.37 55 275 4.58 2.2 0.79 0.35 0.67 0.44 4.66 1,398 4,439 18,034 626 626 3,812 0.09 291.41 56 280 4.67 2.3 0.82 0.35 0.70 0.47 5.04 1,512 5,325 18,129 629 629 4,695 0.11 291.46 57 285 4.75 2.4 0.86 0.35 0.73 0.51 5.42 1,627 6,322 18,235 633 633 5,689 0.13 291.51 58 290 4.83 2.4 0.86 0.35 0.73 0.51 5.42 1,627 7,316 18,341 637 637 6,679 0.15 291.56 59 295 4.92 2.5 0.89 0.35 0.76 0.54 5.80 1,741 8,420 18,459 641 641 7,780 0.18 291.62 60 300 5.00 2.6 0.93 0.35 0.79 0.58 6.19 1,856 9,636 18,589 645 645 8,990 0.21 291.69 61 305 5.08 3.1 1.11 0.35 0.94 0.76 8.10 2,429 11,419 18,780 652 652 10,767 0.25 291.79 62 310 5.17 3.6 1.29 0.35 1.09 0.94 10.01 3,002 13,769 19,031 661 661 13,108 0.30 291.91 63 315 5.25 3.9 1.39 0.35 1.19 1.04 11.15 3,346 16,454 19,306 670 670 15,784 0.36 292.06 64 320 5.33 4.2 1.50 0.35 1.28 1.15 12.30 3,690 19,473 19,608 681 681 18,792 0.43 292.20 65 325 5.42 4.7 1.68 0.35 1.43 1.33 14.21 4,262 23,055 19,966 693 693 22,361 0.51 292.38 66 330 5.50 5.6 2.00 0.35 1.70 1.65 17.65 5,294 27,655 20,427 709 709 26,946 0.62 292.61 67 335 5.58 1.9 0.68 0.35 0.58 0.33 3.51 1,054 28,000 20,462 710 710 27,289 0.63 292.63 68 340 5.67 0.9 0.32 0.35 0.27 0.05 0.52 155 27,444 20,406 709 709 26,736 0.61 292.60 69 345 5.75 0.6 0.21 0.35 0.18 0.03 0.34 103 26,839 20,345 706 706 26,132 0.60 292.57 70 350 5.83 0.5 0.18 0.35 0.15 0.03 0.29 86 26,218 20,283 704 704 25,514 0.59 292.54 71 355 5.92 0.3 0.11 0.35 0.09 0.02 0.17 52 25,566 20,218 702 702 24,864 0.57 292.51 72 360 6.00 0.2 0.07 0.35 0.06 0.01 0.11 34 24,898 20,151 700 700 24,198 0.56 292.47 TOTAL RAINFALL RAINFALL VOLUME SOIL LOSSES EFFECTIVE RAIN FLOOD VOLUME FLOOD VOLUME REQUIRED STORAGE REQUIRED STORAGE MAX WSEL PEAK FLOW RATE TOTAL BASIN LOSSES AVERAGE PERCOLATION RATE EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY 68.29 cf/min 24,584 cu-ft 1.27 in 1.12 acft 48,782 cu-ft 0.63 acft 27,289 cu-ft 114,590 cu-ft 2.98 in 65,808 cu-ft 292.63 ft 17.65 cfs Plate E-2.2 6-Hour Storm Page 9 of 13 PROJECT: Job No.:2636 BY:FOS DATE 1/9/24 DRAINAGE AREA-ACRES 10.59 VARIABLE LOSS RATE (AVG) IN/HR Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 15 Fm = Minimum value on loss curve (in/hr)0.18 LAG TIME - MINUTES 2.47 C 0.00325 Maxwell Drywells UNIT TIME-PERCENT OF LAG 607%Low Loss Rate (percent)85.00%Number 50 TOTAL ADJUSTED STORM RAIN (in)4.59 Drywell Percolation Rate 0.00 cfs 0.00 cfm Unit Time Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 15 0.25 0.2 0.037 0.619 0.031 0.01 0.06 53 53 17,566 1,830 53 0 0.00 291.20 2 30 0.50 0.3 0.055 0.612 0.047 0.01 0.09 79 79 17,568 1,830 79 0 0.00 291.20 3 45 0.75 0.3 0.055 0.605 0.047 0.01 0.09 79 79 17,568 1,830 79 0 0.00 291.20 4 60 1.00 0.4 0.073 0.598 0.062 0.01 0.12 106 106 17,571 1,830 106 0 0.00 291.20 5 75 1.25 0.3 0.055 0.591 0.047 0.01 0.09 79 79 17,568 1,830 79 0 0.00 291.20 6 90 1.50 0.3 0.055 0.584 0.047 0.01 0.09 79 79 17,568 1,830 79 0 0.00 291.20 7 105 1.75 0.3 0.055 0.577 0.047 0.01 0.09 79 79 17,568 1,830 79 0 0.00 291.20 8 120 2.00 0.4 0.073 0.570 0.062 0.01 0.12 106 106 17,571 1,830 106 0 0.00 291.20 9 135 2.25 0.4 0.073 0.563 0.062 0.01 0.12 106 106 17,571 1,830 106 0 0.00 291.20 10 150 2.50 0.4 0.073 0.556 0.062 0.01 0.12 106 106 17,571 1,830 106 0 0.00 291.20 11 165 2.75 0.5 0.092 0.549 0.078 0.01 0.15 132 132 17,574 1,831 132 0 0.00 291.20 12 180 3.00 0.5 0.092 0.542 0.078 0.01 0.15 132 132 17,574 1,831 132 0 0.00 291.20 13 195 3.25 0.5 0.092 0.536 0.078 0.01 0.15 132 132 17,574 1,831 132 0 0.00 291.20 14 210 3.50 0.5 0.092 0.529 0.078 0.01 0.15 132 132 17,574 1,831 132 0 0.00 291.20 15 225 3.75 0.5 0.092 0.522 0.078 0.01 0.15 132 132 17,574 1,831 132 0 0.00 291.20 16 240 4.00 0.6 0.110 0.516 0.094 0.02 0.18 159 159 17,577 1,831 159 0 0.00 291.20 17 255 4.25 0.6 0.110 0.509 0.094 0.02 0.18 159 159 17,577 1,831 159 0 0.00 291.20 18 270 4.50 0.7 0.129 0.503 0.109 0.02 0.21 185 185 17,580 1,831 185 0 0.00 291.20 19 285 4.75 0.7 0.129 0.496 0.109 0.02 0.21 185 185 17,580 1,831 185 0 0.00 291.20 20 300 5.00 0.8 0.147 0.490 0.125 0.02 0.24 212 212 17,583 1,832 212 0 0.00 291.20 21 315 5.25 0.6 0.110 0.484 0.094 0.02 0.18 159 159 17,577 1,831 159 0 0.00 291.20 22 330 5.50 0.7 0.129 0.477 0.109 0.02 0.21 185 185 17,580 1,831 185 0 0.00 291.20 23 345 5.75 0.8 0.147 0.471 0.125 0.02 0.24 212 212 17,583 1,832 212 0 0.00 291.20 24 360 6.00 0.8 0.147 0.465 0.125 0.02 0.24 212 212 17,583 1,832 212 0 0.00 291.20 25 375 6.25 0.9 0.165 0.459 0.140 0.02 0.26 238 238 17,585 1,832 238 0 0.00 291.20 26 390 6.50 0.9 0.165 0.452 0.140 0.02 0.26 238 238 17,585 1,832 238 0 0.00 291.20 27 405 6.75 1.0 0.184 0.446 0.156 0.03 0.29 265 265 17,588 1,832 265 0 0.00 291.20 28 420 7.00 1.0 0.184 0.440 0.156 0.03 0.29 265 265 17,588 1,832 265 0 0.00 291.20 29 435 7.25 1.0 0.184 0.434 0.156 0.03 0.29 265 265 17,588 1,832 265 0 0.00 291.20 30 450 7.50 1.1 0.202 0.428 0.172 0.03 0.32 291 291 17,591 1,832 291 0 0.00 291.20 31 465 7.75 1.2 0.220 0.423 0.187 0.03 0.35 318 318 17,594 1,833 318 0 0.00 291.20 32 480 8.00 1.3 0.239 0.417 0.203 0.04 0.38 344 344 17,597 1,833 344 0 0.00 291.20 33 495 8.25 1.5 0.275 0.411 0.234 0.04 0.44 397 397 17,602 1,834 397 0 0.00 291.20 34 510 8.50 1.5 0.275 0.405 0.234 0.04 0.44 397 397 17,602 1,834 397 0 0.00 291.20 35 525 8.75 1.6 0.294 0.400 0.250 0.04 0.47 424 424 17,605 1,834 424 0 0.00 291.20 36 540 9.00 1.7 0.312 0.394 0.265 0.05 0.50 450 450 17,608 1,834 450 0 0.00 291.20 37 555 9.25 1.9 0.349 0.388 0.297 0.05 0.56 503 503 17,614 1,835 503 0 0.00 291.20 38 570 9.50 2.0 0.367 0.383 0.312 0.06 0.59 529 529 17,617 1,835 529 0 0.00 291.20 39 585 9.75 2.1 0.386 0.377 0.328 0.01 0.09 79 79 17,568 1,830 79 0 0.00 291.20 40 600 10.00 2.2 0.404 0.372 0.343 0.03 0.34 307 307 17,593 1,833 307 0 0.00 291.20 41 615 10.25 1.5 0.275 0.367 0.234 0.04 0.44 397 397 17,602 1,834 397 0 0.00 291.20 42 630 10.50 1.5 0.275 0.361 0.234 0.04 0.44 397 397 17,602 1,834 397 0 0.00 291.20 43 645 10.75 2.0 0.367 0.356 0.312 0.01 0.12 108 108 17,571 1,830 108 0 0.00 291.20 in/hr Total In Basin UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Loss Rate Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD MANUAL 24-HOUR STORM Basin Losses Plate E-2.2 24-Hour Storm Page 10 of 13 PROJECT: Job No.:2636 BY:FOS DATE 1/9/24 DRAINAGE AREA-ACRES 10.59 VARIABLE LOSS RATE (AVG) IN/HR Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 15 Fm = Minimum value on loss curve (in/hr)0.18 LAG TIME - MINUTES 2.47 C 0.00325 Maxwell Drywells UNIT TIME-PERCENT OF LAG 607%Low Loss Rate (percent)85.00%Number 50 TOTAL ADJUSTED STORM RAIN (in)4.59 Drywell Percolation Rate 0.00 cfs 0.00 cfm Unit Time Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft in/hr Total In Basin UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Loss Rate Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD MANUAL 24-HOUR STORM Basin Losses 44 660 11.00 2.0 0.367 0.351 0.312 0.02 0.18 158 158 17,577 1,831 158 0 0.00 291.20 45 675 11.25 1.9 0.349 0.346 0.297 0.00 0.03 31 31 17,563 1,830 31 0 0.00 291.20 46 690 11.50 1.9 0.349 0.341 0.297 0.01 0.09 80 80 17,569 1,830 80 0 0.00 291.20 47 705 11.75 1.7 0.312 0.336 0.265 0.05 0.50 450 450 17,608 1,834 450 0 0.00 291.20 48 720 12.00 1.8 0.330 0.331 0.281 0.05 0.53 477 477 17,611 1,834 477 0 0.00 291.20 49 735 12.25 2.5 0.459 0.326 0.390 0.13 1.43 1,283 1,283 17,697 1,843 1,283 0 0.00 291.20 50 750 12.50 2.6 0.477 0.321 0.406 0.16 1.67 1,506 1,506 17,721 1,846 1,506 0 0.00 291.20 51 765 12.75 2.8 0.514 0.316 0.437 0.20 2.12 1,905 1,905 17,764 1,850 1,850 55 0.00 291.20 52 780 13.00 2.9 0.532 0.311 0.453 0.22 2.36 2,128 2,182 17,793 1,853 1,853 329 0.01 291.22 53 795 13.25 3.4 0.624 0.306 0.531 0.32 3.39 3,055 3,384 17,921 1,867 1,867 1,517 0.03 291.28 54 810 13.50 3.4 0.624 0.302 0.531 0.32 3.44 3,100 4,617 18,053 1,881 1,881 2,737 0.06 291.35 55 825 13.75 2.3 0.422 0.297 0.359 0.13 1.34 1,202 3,939 17,981 1,873 1,873 2,066 0.05 291.31 56 840 14.00 2.3 0.422 0.293 0.359 0.13 1.38 1,246 3,312 17,914 1,866 1,866 1,446 0.03 291.28 57 855 14.25 2.7 0.496 0.288 0.421 0.21 2.22 1,995 3,441 17,928 1,867 1,867 1,574 0.04 291.29 58 870 14.50 2.6 0.477 0.284 0.406 0.19 2.07 1,861 3,434 17,927 1,867 1,867 1,567 0.04 291.29 59 885 14.75 2.6 0.477 0.279 0.406 0.20 2.11 1,902 3,469 17,931 1,868 1,868 1,601 0.04 291.29 60 900 15.00 2.5 0.459 0.275 0.390 0.18 1.96 1,767 3,368 17,920 1,867 1,867 1,502 0.03 291.28 61 915 15.25 2.4 0.441 0.271 0.375 0.17 1.81 1,631 3,133 17,895 1,864 1,864 1,269 0.03 291.27 62 930 15.50 2.3 0.422 0.267 0.359 0.16 1.66 1,494 2,763 17,855 1,860 1,860 903 0.02 291.25 63 945 15.75 1.9 0.349 0.263 0.297 0.09 0.92 828 1,731 17,745 1,848 1,731 0 0.00 291.20 64 960 16.00 1.9 0.349 0.259 0.297 0.09 0.96 866 866 17,653 1,839 866 0 0.00 291.20 65 975 16.25 0.4 0.073 0.255 0.062 0.01 0.12 106 106 17,571 1,830 106 0 0.00 291.20 66 990 16.50 0.4 0.073 0.251 0.062 0.01 0.12 106 106 17,571 1,830 106 0 0.00 291.20 67 1005 16.75 0.3 0.055 0.247 0.047 0.01 0.09 79 79 17,568 1,830 79 0 0.00 291.20 68 1020 17.00 0.3 0.055 0.243 0.047 0.01 0.09 79 79 17,568 1,830 79 0 0.00 291.20 69 1035 17.25 0.5 0.092 0.240 0.078 0.01 0.15 132 132 17,574 1,831 132 0 0.00 291.20 70 1050 17.50 0.5 0.092 0.236 0.078 0.01 0.15 132 132 17,574 1,831 132 0 0.00 291.20 71 1065 17.75 0.5 0.092 0.233 0.078 0.01 0.15 132 132 17,574 1,831 132 0 0.00 291.20 72 1080 18.00 0.4 0.073 0.229 0.062 0.01 0.12 106 106 17,571 1,830 106 0 0.00 291.20 73 1095 18.25 0.4 0.073 0.226 0.062 0.01 0.12 106 106 17,571 1,830 106 0 0.00 291.20 74 1110 18.50 0.4 0.073 0.222 0.062 0.01 0.12 106 106 17,571 1,830 106 0 0.00 291.20 75 1125 18.75 0.3 0.055 0.219 0.047 0.01 0.09 79 79 17,568 1,830 79 0 0.00 291.20 76 1140 19.00 0.2 0.037 0.216 0.031 0.01 0.06 53 53 17,566 1,830 53 0 0.00 291.20 77 1155 19.25 0.3 0.055 0.213 0.047 0.01 0.09 79 79 17,568 1,830 79 0 0.00 291.20 78 1170 19.50 0.4 0.073 0.210 0.062 0.01 0.12 106 106 17,571 1,830 106 0 0.00 291.20 79 1185 19.75 0.3 0.055 0.207 0.047 0.01 0.09 79 79 17,568 1,830 79 0 0.00 291.20 80 1200 20.00 0.2 0.037 0.204 0.031 0.01 0.06 53 53 17,566 1,830 53 0 0.00 291.20 81 1215 20.25 0.3 0.055 0.202 0.047 0.01 0.09 79 79 17,568 1,830 79 0 0.00 291.20 82 1230 20.50 0.3 0.055 0.199 0.047 0.01 0.09 79 79 17,568 1,830 79 0 0.00 291.20 83 1245 20.75 0.3 0.055 0.197 0.047 0.01 0.09 79 79 17,568 1,830 79 0 0.00 291.20 84 1260 21.00 0.2 0.037 0.194 0.031 0.01 0.06 53 53 17,566 1,830 53 0 0.00 291.20 85 1275 21.25 0.3 0.055 0.192 0.047 0.01 0.09 79 79 17,568 1,830 79 0 0.00 291.20 86 1290 21.50 0.2 0.037 0.190 0.031 0.01 0.06 53 53 17,566 1,830 53 0 0.00 291.20 Plate E-2.2 24-Hour Storm Page 11 of 13 PROJECT: Job No.:2636 BY:FOS DATE 1/9/24 DRAINAGE AREA-ACRES 10.59 VARIABLE LOSS RATE (AVG) IN/HR Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 15 Fm = Minimum value on loss curve (in/hr)0.18 LAG TIME - MINUTES 2.47 C 0.00325 Maxwell Drywells UNIT TIME-PERCENT OF LAG 607%Low Loss Rate (percent)85.00%Number 50 TOTAL ADJUSTED STORM RAIN (in)4.59 Drywell Percolation Rate 0.00 cfs 0.00 cfm Unit Time Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft in/hr Total In Basin UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Loss Rate Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD MANUAL 24-HOUR STORM Basin Losses 87 1305 21.75 0.3 0.055 0.188 0.047 0.01 0.09 79 79 17,568 1,830 79 0 0.00 291.20 88 1320 22.00 0.2 0.037 0.186 0.031 0.01 0.06 53 53 17,566 1,830 53 0 0.00 291.20 89 1335 22.25 0.3 0.055 0.184 0.047 0.01 0.09 79 79 17,568 1,830 79 0 0.00 291.20 90 1350 22.50 0.2 0.037 0.182 0.031 0.01 0.06 53 53 17,566 1,830 53 0 0.00 291.20 91 1365 22.75 0.2 0.037 0.181 0.031 0.01 0.06 53 53 17,566 1,830 53 0 0.00 291.20 92 1380 23.00 0.2 0.037 0.179 0.031 0.01 0.06 53 53 17,566 1,830 53 0 0.00 291.20 93 1395 23.25 0.2 0.037 0.178 0.031 0.01 0.06 53 53 17,566 1,830 53 0 0.00 291.20 94 1410 23.50 0.2 0.037 0.177 0.031 0.01 0.06 53 53 17,566 1,830 53 0 0.00 291.20 95 1425 23.75 0.2 0.037 0.176 0.031 0.01 0.06 53 53 17,566 1,830 53 0 0.00 291.20 96 1440 24.00 0.2 0.037 0.175 0.031 0.01 0.06 53 53 17,566 1,830 53 0 0.00 291.20 EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY TOTAL RAINFALL RAINFALL VOLUME SOIL LOSSES EFFECTIVE RAIN FLOOD VOLUME FLOOD VOLUME REQUIRED STORAGE REQUIRED STORAGE MAX WSEL PEAK FLOW RATE TOTAL BASIN LOSSES AVERAGE PERCOLATION RATE 40,920 cu-ft 28.42 cf/min 1.06 in 0.94 acft 40,920 cu-ft 0.06 acft 2,737 cu-ft 4.59 in 176,500 cu-ft 135,580 cu-ft 291.35 ft 3.44 cfs Plate E-2.2 24-Hour Storm Page 12 of 13 PROECT JOB No. BASIN DESIGNATION: BASIN CHARACTERISTICS CONTOUR ELEVATION INCR TOTAL INCR TOTAL INCR (ft)(ft)(sf)(sf)(cuft)(cuft)(acre-ft) 291.2 0 0 17,560 0 0 0.00 292 0.8 0.8 1,567 19,127 14,670 14,670 0.34 293 1 1.8 2,015 21,142 20,126 34,796 0.80 294 1 2.8 2,083 23,225 22,175 56,972 1.31 295 1 3.8 2,144 25,369 24,289 81,261 1.87 WHERE: TOTAL Retention Basin E BASIN VOLUME WORKSHEET DEPTH AREA VOLUME Del Webb Explore at Palm Desert 2636 ()()2121213 1 AAAAEEV++−= Basin Volume Worksheet Page 13 of 13 FOS 2 AMC II AREA SOIL TRIBUTARY AREAS ACRES LOW LOSS RI INFILTRATION IMPERVIOUS DESIG GROUP CONDITION NUMBER RATE PERCENT 4 A SF - DETACHED 2.166 D 32 0.74 0.50 9 A LANDSCAPING 0.581 D 32 0.74 0.10 2 A PAVING/HARDSCAPE 1.097 D 32 0.74 1.00 498 ft 249 ft 310.3 ft ELEVATION OF CONCENTRATION POINT 303.7 ft 0.02 100 LOW LOSS RATE (Storm Events > 10 Years)85% POINT RAIN FROM NOAA ATLAS 14 1-HOUR 1.57 in 3-HOUR 2.27 in 6-HOUR 2.98 in 24-HOUR 4.59 in BASIN CHARACTERISTICS:ELEVATION AREA 302.0 ft 14,437 sf 303.0 ft 16,041 sf 304.0 ft 17,712 sf PERCOLATION RATE (in/hr)5.0 in/hr DRYWELL DATA NUMBER USED PERCOLATION RATE LOWEST FLOWLINE ELEVATION 303.67 LOWEST PAD ELEVATION 305.6 LENGTH OF WATERCOURSE (L) AREA DESIGNATION ELEVATION OF HEADWATER AVERAGE MANNINGS 'N' VALUE STORM FREQUENCY (YEAR) LENGTH TO POINT OPPOSITE CENTROID (Lca) Low Loss Conditions: X=Existing; D=Developed; BS=Retention DA-F RCFCD SYNTHETIC UNIT HYDROGRAPH - SHORTCUT METHOD DATA INPUT SHEET WORKSHEET PREPARED BY: PROJECT NAME DATE January 9, 2024 Del Webb Explore at Palm Desert PROJECT NUMBER CONCENTRATION POINT DESIGNATION 2636 Retention Basin F AMC NUMBER Data Input Sheet Page 1 of 13 PROJECT: Job No.: BY:DATE:1/9/24 [1] AMC II [2] FREQUENCY-YEARS 100 FROM NOAA ATLAS 14 [3] STORM DURATION:Point Rain 1-HOUR 1.57 in 3-HOUR 2.27 in 6-HOUR 2.98 in 24-HOUR 4.59 in STORM DURATION 1-HOUR 3-HOUR 6-HOUR 24-HOUR RAINFALL VOLUME (cu-ft)21,903 31,669 41,575 64,036 SOIL LOSSES (cu-ft)4,915 14,382 23,946 49,307 EFFECTIVE RAIN (in)1.22 1.24 1.26 1.06 FLOOD VOLUME (cu-ft)16,989 17,287 17,629 14,730 (acre-ft)0.39 0.40 0.40 0.34 REQUIRED STORAGE (cu-ft)11,046 6,788 5,403 0 (acre-ft)0.25 0.16 0.12 0.00 FACTOR OF SAFETY 2.91 4.73 5.94 #DIV/0! STORAGE PROVIDED (cu-ft) (acre-ft) PEAK FLOW (cfs)n/a 7.29 6.40 1.24 MAXIMUM WSEL (ft)302.73 302.45 302.35 302.00 DEPTH (ft)0.73 0.45 0.35 0.00 DIFFERENCE (ft)0.94 1.22 1.32 1.67 DIFFERENCE (ft)2.87 3.15 3.25 3.60 ESTIMATED TIME TO DEWATER BASIN Based on Total Flood Volume & Average Percolation Rate (days)0.1 0.2 0.3 1.0 [18] 200% OF LAG-MINUTES RAINFALL DATA 3.3 NOTE: PEAK FLOW FOR THE 1-HOUR STORM IS NOT REPRESENTATIVE. PER RCFCD PEAK DISCHARGES FROM THE 3-HOUR STORM SHOULD NORMALLY COMPARE WELL WITH RATIONAL PEAKS. LOWEST PAD ELEVATION LOWEST FLOWLINE ELEVATION STORM EVENT SUMMARY 305.6 303.67 32,102 0.74 0.02 [17] 100% OF LAG-MINUTES 1.6 1.6 [14] AVERAGE MANNINGS 'N' [15] LAG TIME-HOURS 0.03 [16] LAG TIME-MINUTES [13] L*LCA/S^0.5 8.38 [11] S-FEET/MILE [6] La-FEET [7] La-MILES [8] ELEVATION OF HEADWATER 0.001 249.00 [12] S^0.5 0.047 70.3 310.3 303.67 6.63 [3] AREA - ACRES [4] L-FEET [5] L-MILES 498 0.094 Retention Basin F DA-F Del Webb Explore at Palm Desert [10] H-FEET [9] ELEVATION OF CONCENTRATION POINT 3.843 PHYSICAL DATA [1] CONCENTRATION POINT HYDROLOGY MANUAL BASIC DATA CALCULATION FORM 2636 FOS RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD [2] AREA DESIGNATION Plate E-2.1 Page 2 of 13 PROJECT: Job No.: BY:DATE:1/9/24 MAX LOW LOW MIN SOIL RI PERVIOUS DECIMAL ADJUSTED AREA AREA AVERAGE LOSS LOSS RATE AVERAGE GROUP NUMBER AREA PERCENT INFILTRATION WEIGHTED ADJUSTED CONDITION PER ADJUSTED INFILTRATION OF AREA RATE AVERAGE INFILTRATION RCFC/2322 INFILTRATION RATE IMPERVIOUS RATE RATE (in/hr)(in/hr)(in/hr) [Plate C-1][Plate E-6.1][Plate E-6.2][Plate E-6.3] A 32 0.74 50%0.41 2.166 0.563 0.2293 DEVELOPED 0.5000 0.2817 A 32 0.74 10%0.67 0.581 0.151 0.1018 DEVELOPED 0.8200 0.1240 A 32 0.74 100%0.07 1.097 0.285 0.0211 DEVELOPED 0.1000 0.0285 SUM 3.843 SUM 0.3523 0.4343 VARIABLE LOSS RATE CURVE (24-HOUR STORM ONLY) Fm=0.176132535 NOTE: Low loss rates established per RCFC/2322 (Dated: May-30-95) C=0.00326 For 10 Year Storms or Less Ft=C(24-(T/60))^1.55+Fm =0.00326 0.18 in/hr Undeveloped Condition: Low Loss = 90% CONSTANT LOSS RATE (3 & 6 HOUR STORMS)=0.3523 Developed Condition: Low Loss = 0.9 - (0.8 * %impervious) LOW LOSS RATE =0.8500 Basin Site: Low Loss = 10% Where:For 100 Year Storm - Low Loss should be between 80% & 90% T=Time in minutes. To get an average value for each unit time period, Use T=1/2 the unit time for the first time period,of the Rainfall Rate T=1 1/2 unit time for the second period, etc. (24-(T/60))^1.55 + LAND USE SF - DETACHED LANDSCAPING PAVING/HARDSCAPE AVERAGE ADJUSTED LOSS RATE RCFC & WCD HYDROLOGY MANUAL SYNTHETIC UNIT HYDROGRAPH METHOD BASIC DATA CALCULATION FORM Del Webb Explore at Palm Desert FOS 2636 AMC II Plate E-2.1 Page 3 of 13 PROJECT: Job No.:2636 BY:FOS DATE 1/9/24 DRAINAGE AREA-ACRES 3.84 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 1.64 Maxwell Drywells UNIT TIME-PERCENT OF LAG 304.9 Number 0 TOTAL ADJUSTED STORM RAIN-INCHES 1.57 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE-in/hr 0.35 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 5 0.08 3.6 0.68 0.35 0.58 0.33 1.26 379 379 14,477 503 379 0 0.00 302.00 2 10 0.17 4.2 0.79 0.35 0.67 0.44 1.70 510 510 14,491 503 503 7 0.00 302.00 3 15 0.25 4.4 0.83 0.35 0.70 0.48 1.85 554 561 14,496 503 503 58 0.00 302.00 4 20 0.33 4.6 0.87 0.35 0.74 0.51 1.99 598 656 14,506 504 504 152 0.00 302.01 5 25 0.42 5.0 0.94 0.35 0.80 0.59 2.29 686 838 14,525 504 504 334 0.01 302.02 6 30 0.50 5.6 1.06 0.35 0.90 0.70 2.72 817 1,151 14,558 505 505 645 0.01 302.04 7 35 0.58 6.4 1.21 0.35 1.02 0.85 3.31 992 1,638 14,609 507 507 1,130 0.03 302.07 8 40 0.67 8.1 1.53 0.35 1.30 1.17 4.55 1,365 2,495 14,700 510 510 1,985 0.05 302.13 9 45 0.75 13.1 2.47 0.35 2.10 2.12 8.20 2,460 4,444 14,905 518 518 3,927 0.09 302.26 10 50 0.83 34.5 6.50 0.35 5.52 6.15 23.82 7,147 11,074 15,603 542 542 10,532 0.24 302.69 11 55 0.92 6.7 1.26 0.35 1.07 0.91 3.53 1,058 11,590 15,657 544 544 11,046 0.25 302.73 12 60 1.00 3.8 0.72 0.35 0.61 0.36 1.41 423 11,469 15,645 543 543 10,926 0.25 302.72 TOTAL RAINFALL 1.57 in RAINFALL VOLUME 21,903 cu-ft SOIL LOSSES 4,915 cu-ft EFFECTIVE RAIN 1.22 in FLOOD VOLUME 0.39 acft FLOOD VOLUME 16,989 cu-ft REQUIRED STORAGE 0.25 REQUIRED STORAGE 11,046 cu-ft MAX WSEL 302.73 ft PEAK FLOW RATE 23.82 cfs TOTAL BASIN LOSSES 6,063 cu-ft AVERAGE PERCOLATION RATE 101.05 cf/min EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Total In Basin in/hr Time Loss Rate Basin Losses Del Webb Explore at Palm DesertRCFC & WCD HYDROLOGY MANUAL SYNTHETIC UNIT HYDROGRAPH METHOD SHORTCUT METHOD 1-HOUR STORM Plate E-2.2 1-Hour Storm Page 4 of 13 PROJECT: Job No.:2636 BY:FOS DATE DRAINAGE AREA-ACRES 3.84 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 1.64 Maxwell Drywells UNIT TIME-PERCENT OF LAG 304.9 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.27 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.35 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 5 0.08 1.3 0.35 0.35 0.30 0.00 0.01 2 2 14,437 501 2 0 0.00 302.00 2 10 0.17 1.3 0.35 0.35 0.30 0.00 0.01 2 2 14,437 501 2 0 0.00 302.00 3 15 0.25 1.1 0.30 0.35 0.25 0.04 0.17 52 52 14,443 501 52 0 0.00 302.00 4 20 0.33 1.5 0.41 0.35 0.35 0.06 0.22 65 65 14,444 502 65 0 0.00 302.00 5 25 0.42 1.5 0.41 0.35 0.35 0.06 0.22 65 65 14,444 502 65 0 0.00 302.00 6 30 0.50 1.8 0.49 0.35 0.42 0.14 0.54 161 161 14,454 502 161 0 0.00 302.00 7 35 0.58 1.5 0.41 0.35 0.35 0.06 0.22 65 65 14,444 502 65 0 0.00 302.00 8 40 0.67 1.8 0.49 0.35 0.42 0.14 0.54 161 161 14,454 502 161 0 0.00 302.00 9 45 0.75 1.8 0.49 0.35 0.42 0.14 0.54 161 161 14,454 502 161 0 0.00 302.00 10 50 0.83 1.5 0.41 0.35 0.35 0.06 0.22 65 65 14,444 502 65 0 0.00 302.00 11 55 0.92 1.6 0.44 0.35 0.37 0.08 0.32 97 97 14,447 502 97 0 0.00 302.00 12 60 1.00 1.8 0.49 0.35 0.42 0.14 0.54 161 161 14,454 502 161 0 0.00 302.00 13 65 1.08 2.2 0.60 0.35 0.51 0.25 0.96 287 287 14,467 502 287 0 0.00 302.00 14 70 1.17 2.2 0.60 0.35 0.51 0.25 0.96 287 287 14,467 502 287 0 0.00 302.00 15 75 1.25 2.2 0.60 0.35 0.51 0.25 0.96 287 287 14,467 502 287 0 0.00 302.00 16 80 1.33 2.0 0.54 0.35 0.46 0.19 0.75 224 224 14,461 502 224 0 0.00 302.00 17 85 1.42 2.6 0.71 0.35 0.60 0.36 1.38 414 414 14,481 503 414 0 0.00 302.00 18 90 1.50 2.7 0.74 0.35 0.63 0.38 1.49 446 446 14,484 503 446 0 0.00 302.00 19 95 1.58 2.4 0.65 0.35 0.56 0.30 1.17 351 351 14,474 503 351 0 0.00 302.00 20 100 1.67 2.7 0.74 0.35 0.63 0.38 1.49 446 446 14,484 503 446 0 0.00 302.00 21 105 1.75 3.3 0.90 0.35 0.76 0.55 2.12 636 636 14,504 504 504 132 0.00 302.01 22 110 1.83 3.1 0.84 0.35 0.72 0.49 1.91 572 704 14,511 504 504 200 0.00 302.01 23 115 1.92 2.9 0.79 0.35 0.67 0.44 1.70 509 709 14,512 504 504 205 0.00 302.01 24 120 2.00 3.0 0.82 0.35 0.69 0.46 1.80 541 746 14,516 504 504 242 0.01 302.02 25 125 2.08 3.1 0.84 0.35 0.72 0.49 1.91 572 814 14,523 504 504 310 0.01 302.02 RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 3-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Loss Rate Basin Losses Plate E-2.2 3-Hour Storm Page 5 of 13 PROJECT: Job No.:2636 BY:FOS DATE DRAINAGE AREA-ACRES 3.84 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 1.64 Maxwell Drywells UNIT TIME-PERCENT OF LAG 304.9 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.27 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.35 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 3-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Loss Rate Basin Losses 26 130 2.17 4.2 1.14 0.35 0.97 0.79 3.07 921 1,230 14,567 506 506 725 0.02 302.05 27 135 2.25 5.0 1.36 0.35 1.16 1.01 3.91 1,174 1,898 14,637 508 508 1,390 0.03 302.09 28 140 2.33 3.5 0.95 0.35 0.81 0.60 2.33 699 2,089 14,657 509 509 1,580 0.04 302.10 29 145 2.42 6.8 1.85 0.35 1.57 1.50 5.81 1,744 3,324 14,787 513 513 2,811 0.06 302.18 30 150 2.50 7.3 1.99 0.35 1.69 1.64 6.34 1,902 4,713 14,933 519 519 4,194 0.10 302.28 31 155 2.58 8.2 2.23 0.35 1.90 1.88 7.29 2,187 6,382 15,109 525 525 5,857 0.13 302.38 32 160 2.67 5.9 1.61 0.35 1.37 1.25 4.86 1,459 7,316 15,207 528 528 6,788 0.16 302.45 33 165 2.75 2.0 0.54 0.35 0.46 0.19 0.75 224 7,012 15,175 527 527 6,485 0.15 302.43 34 170 2.83 1.8 0.49 0.35 0.42 0.14 0.54 161 6,646 15,137 526 526 6,120 0.14 302.40 35 175 2.92 1.8 0.49 0.35 0.42 0.14 0.54 161 6,280 15,098 524 524 5,756 0.13 302.38 36 180 3.00 0.6 0.16 0.35 0.14 0.02 0.10 29 5,785 15,046 522 522 5,262 0.12 302.35 TOTAL RAIN RAINFALL VOLUME SOIL LOSSES EFFECTIVE RAIN FLOOD VOLUME FLOOD VOLUME REQUIRED STORAGE REQUIRED STORAGE MAX WSEL PEAK FLOW RATE TOTAL BASIN LOSSES AVERAGE PERCOLATION RATE EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY 12,025 cu-ft 66.80 cf/min 1.24 in 0.40 acft 17,287 cu-ft 0.16 acft 6,788 cu-ft 14,382 cu-ft 2.27 in 31,669 cu-ft 302.45 ft 7.29 cfs Plate E-2.2 3-Hour Storm Page 6 of 13 PROJECT: Job No.:2636 BY:FOS DATE 1/9/24 DRAINAGE AREA-ACRES 3.84 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 1.64 Maxwell Drywells UNIT TIME-PERCENT OF LAG 304.9 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.98 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.35 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 5 0.08 0.5 0.18 0.35 0.15 0.03 0.10 31 31 14,440 501 31 0 0.00 302.00 2 10 0.17 0.6 0.21 0.35 0.18 0.03 0.12 37 37 14,441 501 37 0 0.00 302.00 3 15 0.25 0.6 0.21 0.35 0.18 0.03 0.12 37 37 14,441 501 37 0 0.00 302.00 4 20 0.33 0.6 0.21 0.35 0.18 0.03 0.12 37 37 14,441 501 37 0 0.00 302.00 5 25 0.42 0.6 0.21 0.35 0.18 0.03 0.12 37 37 14,441 501 37 0 0.00 302.00 6 30 0.50 0.7 0.25 0.35 0.21 0.04 0.15 44 44 14,442 501 44 0 0.00 302.00 7 35 0.58 0.7 0.25 0.35 0.21 0.04 0.15 44 44 14,442 501 44 0 0.00 302.00 8 40 0.67 0.7 0.25 0.35 0.21 0.04 0.15 44 44 14,442 501 44 0 0.00 302.00 9 45 0.75 0.7 0.25 0.35 0.21 0.04 0.15 44 44 14,442 501 44 0 0.00 302.00 10 50 0.83 0.7 0.25 0.35 0.21 0.04 0.15 44 44 14,442 501 44 0 0.00 302.00 11 55 0.92 0.7 0.25 0.35 0.21 0.04 0.15 44 44 14,442 501 44 0 0.00 302.00 12 60 1.00 0.8 0.29 0.35 0.24 0.04 0.17 50 50 14,442 501 50 0 0.00 302.00 13 65 1.08 0.8 0.29 0.35 0.24 0.04 0.17 50 50 14,442 501 50 0 0.00 302.00 14 70 1.17 0.8 0.29 0.35 0.24 0.04 0.17 50 50 14,442 501 50 0 0.00 302.00 15 75 1.25 0.8 0.29 0.35 0.24 0.04 0.17 50 50 14,442 501 50 0 0.00 302.00 16 80 1.33 0.8 0.29 0.35 0.24 0.04 0.17 50 50 14,442 501 50 0 0.00 302.00 17 85 1.42 0.8 0.29 0.35 0.24 0.04 0.17 50 50 14,442 501 50 0 0.00 302.00 18 90 1.50 0.8 0.29 0.35 0.24 0.04 0.17 50 50 14,442 501 50 0 0.00 302.00 19 95 1.58 0.8 0.29 0.35 0.24 0.04 0.17 50 50 14,442 501 50 0 0.00 302.00 20 100 1.67 0.8 0.29 0.35 0.24 0.04 0.17 50 50 14,442 501 50 0 0.00 302.00 21 105 1.75 0.8 0.29 0.35 0.24 0.04 0.17 50 50 14,442 501 50 0 0.00 302.00 22 110 1.83 0.8 0.29 0.35 0.24 0.04 0.17 50 50 14,442 501 50 0 0.00 302.00 23 115 1.92 0.8 0.29 0.35 0.24 0.04 0.17 50 50 14,442 501 50 0 0.00 302.00 24 120 2.00 0.9 0.32 0.35 0.27 0.05 0.19 56 56 14,443 501 56 0 0.00 302.00 Loss Rate RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 6-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Basin Losses Plate E-2.2 6-Hour Storm Page 7 of 13 PROJECT: Job No.:2636 BY:FOS DATE 1/9/24 DRAINAGE AREA-ACRES 3.84 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 1.64 Maxwell Drywells UNIT TIME-PERCENT OF LAG 304.9 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.98 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.35 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft Loss Rate RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 6-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Basin Losses 25 125 2.08 0.8 0.29 0.35 0.24 0.04 0.17 50 50 14,442 501 50 0 0.00 302.00 26 130 2.17 0.9 0.32 0.35 0.27 0.05 0.19 56 56 14,443 501 56 0 0.00 302.00 27 135 2.25 0.9 0.32 0.35 0.27 0.05 0.19 56 56 14,443 501 56 0 0.00 302.00 28 140 2.33 0.9 0.32 0.35 0.27 0.05 0.19 56 56 14,443 501 56 0 0.00 302.00 29 145 2.42 0.9 0.32 0.35 0.27 0.05 0.19 56 56 14,443 501 56 0 0.00 302.00 30 150 2.50 0.9 0.32 0.35 0.27 0.05 0.19 56 56 14,443 501 56 0 0.00 302.00 31 155 2.58 0.9 0.32 0.35 0.27 0.05 0.19 56 56 14,443 501 56 0 0.00 302.00 32 160 2.67 0.9 0.32 0.35 0.27 0.05 0.19 56 56 14,443 501 56 0 0.00 302.00 33 165 2.75 1.0 0.36 0.35 0.30 0.01 0.02 6 6 14,438 501 6 0 0.00 302.00 34 170 2.83 1.0 0.36 0.35 0.30 0.01 0.02 6 6 14,438 501 6 0 0.00 302.00 35 175 2.92 1.0 0.36 0.35 0.30 0.01 0.02 6 6 14,438 501 6 0 0.00 302.00 36 180 3.00 1.0 0.36 0.35 0.30 0.01 0.02 6 6 14,438 501 6 0 0.00 302.00 37 185 3.08 1.0 0.36 0.35 0.30 0.01 0.02 6 6 14,438 501 6 0 0.00 302.00 38 190 3.17 1.1 0.39 0.35 0.33 0.04 0.16 48 48 14,442 501 48 0 0.00 302.00 39 195 3.25 1.1 0.39 0.35 0.33 0.04 0.16 48 48 14,442 501 48 0 0.00 302.00 40 200 3.33 1.1 0.39 0.35 0.33 0.04 0.16 48 48 14,442 501 48 0 0.00 302.00 41 205 3.42 1.2 0.43 0.35 0.36 0.08 0.30 89 89 14,446 502 89 0 0.00 302.00 42 210 3.50 1.3 0.46 0.35 0.40 0.11 0.44 131 131 14,451 502 131 0 0.00 302.00 43 215 3.58 1.4 0.50 0.35 0.43 0.15 0.58 173 173 14,455 502 173 0 0.00 302.00 44 220 3.67 1.4 0.50 0.35 0.43 0.15 0.58 173 173 14,455 502 173 0 0.00 302.00 45 225 3.75 1.5 0.54 0.35 0.46 0.18 0.71 214 214 14,460 502 214 0 0.00 302.00 46 230 3.83 1.5 0.54 0.35 0.46 0.18 0.71 214 214 14,460 502 214 0 0.00 302.00 47 235 3.92 1.6 0.57 0.35 0.49 0.22 0.85 256 256 14,464 502 256 0 0.00 302.00 48 240 4.00 1.6 0.57 0.35 0.49 0.22 0.85 256 256 14,464 502 256 0 0.00 302.00 49 245 4.08 1.7 0.61 0.35 0.52 0.26 0.99 297 297 14,468 502 297 0 0.00 302.00 50 250 4.17 1.8 0.64 0.35 0.55 0.29 1.13 339 339 14,473 503 339 0 0.00 302.00 Plate E-2.2 6-Hour Storm Page 8 of 13 PROJECT: Job No.:2636 BY:FOS DATE 1/9/24 DRAINAGE AREA-ACRES 3.84 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 1.64 Maxwell Drywells UNIT TIME-PERCENT OF LAG 304.9 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.98 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.35 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft Loss Rate RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 6-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Basin Losses 51 255 4.25 1.9 0.68 0.35 0.58 0.33 1.27 380 380 14,477 503 380 0 0.00 302.00 52 260 4.33 2.0 0.72 0.35 0.61 0.36 1.41 422 422 14,481 503 422 0 0.00 302.00 53 265 4.42 2.1 0.75 0.35 0.64 0.40 1.55 464 464 14,486 503 464 0 0.00 302.00 54 270 4.50 2.1 0.75 0.35 0.64 0.40 1.55 464 464 14,486 503 464 0 0.00 302.00 55 275 4.58 2.2 0.79 0.35 0.67 0.43 1.68 505 505 14,490 503 503 2 0.00 302.00 56 280 4.67 2.3 0.82 0.35 0.70 0.47 1.82 547 549 14,495 503 503 45 0.00 302.00 57 285 4.75 2.4 0.86 0.35 0.73 0.51 1.96 588 634 14,504 504 504 130 0.00 302.01 58 290 4.83 2.4 0.86 0.35 0.73 0.51 1.96 588 718 14,513 504 504 214 0.00 302.01 59 295 4.92 2.5 0.89 0.35 0.76 0.54 2.10 630 844 14,526 504 504 340 0.01 302.02 60 300 5.00 2.6 0.93 0.35 0.79 0.58 2.24 671 1,011 14,543 505 505 506 0.01 302.03 61 305 5.08 3.1 1.11 0.35 0.94 0.76 2.93 879 1,385 14,583 506 506 879 0.02 302.06 62 310 5.17 3.6 1.29 0.35 1.09 0.94 3.62 1,087 1,966 14,644 508 508 1,458 0.03 302.10 63 315 5.25 3.9 1.39 0.35 1.19 1.04 4.04 1,212 2,670 14,718 511 511 2,159 0.05 302.14 64 320 5.33 4.2 1.50 0.35 1.28 1.15 4.46 1,337 3,495 14,805 514 514 2,981 0.07 302.20 65 325 5.42 4.7 1.68 0.35 1.43 1.33 5.15 1,544 4,526 14,914 518 518 4,008 0.09 302.26 66 330 5.50 5.6 2.00 0.35 1.70 1.65 6.40 1,919 5,926 15,061 523 523 5,403 0.12 302.35 67 335 5.58 1.9 0.68 0.35 0.58 0.33 1.27 380 5,784 15,046 522 522 5,261 0.12 302.35 68 340 5.67 0.9 0.32 0.35 0.27 0.05 0.19 56 5,318 14,997 521 521 4,797 0.11 302.31 69 345 5.75 0.6 0.21 0.35 0.18 0.03 0.12 37 4,834 14,946 519 519 4,315 0.10 302.28 70 350 5.83 0.5 0.18 0.35 0.15 0.03 0.10 31 4,346 14,895 517 517 3,829 0.09 302.25 71 355 5.92 0.3 0.11 0.35 0.09 0.02 0.06 19 3,848 14,842 515 515 3,333 0.08 302.22 72 360 6.00 0.2 0.07 0.35 0.06 0.01 0.04 12 3,345 14,789 514 514 2,832 0.07 302.19 TOTAL RAINFALL RAINFALL VOLUME SOIL LOSSES EFFECTIVE RAIN FLOOD VOLUME FLOOD VOLUME REQUIRED STORAGE REQUIRED STORAGE MAX WSEL PEAK FLOW RATE TOTAL BASIN LOSSES AVERAGE PERCOLATION RATE EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY 41.10 cf/min 14,797 cu-ft 1.26 in 0.40 acft 17,629 cu-ft 0.12 acft 5,403 cu-ft 41,575 cu-ft 2.98 in 23,946 cu-ft 302.35 ft 6.40 cfs Plate E-2.2 6-Hour Storm Page 9 of 13 PROJECT: Job No.:2636 BY:FOS DATE 1/9/24 DRAINAGE AREA-ACRES 3.84 VARIABLE LOSS RATE (AVG) IN/HR Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 15 Fm = Minimum value on loss curve (in/hr)0.18 LAG TIME - MINUTES 1.64 C 0.00326 Maxwell Drywells UNIT TIME-PERCENT OF LAG 915%Low Loss Rate (percent)85.00%Number 0 TOTAL ADJUSTED STORM RAIN (in)4.59 Drywell Percolation Rate 0.00 cfs 0.00 cfm Unit Time Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 15 0.25 0.2 0.037 0.622 0.031 0.01 0.02 19 19 14,439 1,504 19 0 0.00 302.00 2 30 0.50 0.3 0.055 0.615 0.047 0.01 0.03 29 29 14,440 1,504 29 0 0.00 302.00 3 45 0.75 0.3 0.055 0.608 0.047 0.01 0.03 29 29 14,440 1,504 29 0 0.00 302.00 4 60 1.00 0.4 0.073 0.601 0.062 0.01 0.04 38 38 14,441 1,504 38 0 0.00 302.00 5 75 1.25 0.3 0.055 0.593 0.047 0.01 0.03 29 29 14,440 1,504 29 0 0.00 302.00 6 90 1.50 0.3 0.055 0.586 0.047 0.01 0.03 29 29 14,440 1,504 29 0 0.00 302.00 7 105 1.75 0.3 0.055 0.579 0.047 0.01 0.03 29 29 14,440 1,504 29 0 0.00 302.00 8 120 2.00 0.4 0.073 0.572 0.062 0.01 0.04 38 38 14,441 1,504 38 0 0.00 302.00 9 135 2.25 0.4 0.073 0.566 0.062 0.01 0.04 38 38 14,441 1,504 38 0 0.00 302.00 10 150 2.50 0.4 0.073 0.559 0.062 0.01 0.04 38 38 14,441 1,504 38 0 0.00 302.00 11 165 2.75 0.5 0.092 0.552 0.078 0.01 0.05 48 48 14,442 1,504 48 0 0.00 302.00 12 180 3.00 0.5 0.092 0.545 0.078 0.01 0.05 48 48 14,442 1,504 48 0 0.00 302.00 13 195 3.25 0.5 0.092 0.538 0.078 0.01 0.05 48 48 14,442 1,504 48 0 0.00 302.00 14 210 3.50 0.5 0.092 0.532 0.078 0.01 0.05 48 48 14,442 1,504 48 0 0.00 302.00 15 225 3.75 0.5 0.092 0.525 0.078 0.01 0.05 48 48 14,442 1,504 48 0 0.00 302.00 16 240 4.00 0.6 0.110 0.518 0.094 0.02 0.06 58 58 14,443 1,504 58 0 0.00 302.00 17 255 4.25 0.6 0.110 0.512 0.094 0.02 0.06 58 58 14,443 1,504 58 0 0.00 302.00 18 270 4.50 0.7 0.129 0.505 0.109 0.02 0.07 67 67 14,444 1,505 67 0 0.00 302.00 19 285 4.75 0.7 0.129 0.499 0.109 0.02 0.07 67 67 14,444 1,505 67 0 0.00 302.00 20 300 5.00 0.8 0.147 0.492 0.125 0.02 0.09 77 77 14,445 1,505 77 0 0.00 302.00 21 315 5.25 0.6 0.110 0.486 0.094 0.02 0.06 58 58 14,443 1,504 58 0 0.00 302.00 22 330 5.50 0.7 0.129 0.480 0.109 0.02 0.07 67 67 14,444 1,505 67 0 0.00 302.00 23 345 5.75 0.8 0.147 0.473 0.125 0.02 0.09 77 77 14,445 1,505 77 0 0.00 302.00 24 360 6.00 0.8 0.147 0.467 0.125 0.02 0.09 77 77 14,445 1,505 77 0 0.00 302.00 25 375 6.25 0.9 0.165 0.461 0.140 0.02 0.10 86 86 14,446 1,505 86 0 0.00 302.00 26 390 6.50 0.9 0.165 0.455 0.140 0.02 0.10 86 86 14,446 1,505 86 0 0.00 302.00 27 405 6.75 1.0 0.184 0.449 0.156 0.03 0.11 96 96 14,447 1,505 96 0 0.00 302.00 28 420 7.00 1.0 0.184 0.443 0.156 0.03 0.11 96 96 14,447 1,505 96 0 0.00 302.00 29 435 7.25 1.0 0.184 0.437 0.156 0.03 0.11 96 96 14,447 1,505 96 0 0.00 302.00 30 450 7.50 1.1 0.202 0.431 0.172 0.03 0.12 106 106 14,448 1,505 106 0 0.00 302.00 31 465 7.75 1.2 0.220 0.425 0.187 0.03 0.13 115 115 14,449 1,505 115 0 0.00 302.00 32 480 8.00 1.3 0.239 0.419 0.203 0.04 0.14 125 125 14,450 1,505 125 0 0.00 302.00 33 495 8.25 1.5 0.275 0.413 0.234 0.04 0.16 144 144 14,452 1,505 144 0 0.00 302.00 34 510 8.50 1.5 0.275 0.407 0.234 0.04 0.16 144 144 14,452 1,505 144 0 0.00 302.00 35 525 8.75 1.6 0.294 0.402 0.250 0.04 0.17 154 154 14,453 1,506 154 0 0.00 302.00 36 540 9.00 1.7 0.312 0.396 0.265 0.05 0.18 163 163 14,454 1,506 163 0 0.00 302.00 37 555 9.25 1.9 0.349 0.390 0.297 0.05 0.20 183 183 14,456 1,506 183 0 0.00 302.00 38 570 9.50 2.0 0.367 0.385 0.312 0.06 0.21 192 192 14,457 1,506 192 0 0.00 302.00 39 585 9.75 2.1 0.386 0.379 0.328 0.01 0.02 22 22 14,439 1,504 22 0 0.00 302.00 40 600 10.00 2.2 0.404 0.374 0.343 0.03 0.12 105 105 14,448 1,505 105 0 0.00 302.00 41 615 10.25 1.5 0.275 0.368 0.234 0.04 0.16 144 144 14,452 1,505 144 0 0.00 302.00 42 630 10.50 1.5 0.275 0.363 0.234 0.04 0.16 144 144 14,452 1,505 144 0 0.00 302.00 43 645 10.75 2.0 0.367 0.358 0.312 0.01 0.04 33 33 14,440 1,504 33 0 0.00 302.00 in/hr Total In Basin UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Loss Rate Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD MANUAL 24-HOUR STORM Basin Losses Plate E-2.2 24-Hour Storm Page 10 of 13 PROJECT: Job No.:2636 BY:FOS DATE 1/9/24 DRAINAGE AREA-ACRES 3.84 VARIABLE LOSS RATE (AVG) IN/HR Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 15 Fm = Minimum value on loss curve (in/hr)0.18 LAG TIME - MINUTES 1.64 C 0.00326 Maxwell Drywells UNIT TIME-PERCENT OF LAG 915%Low Loss Rate (percent)85.00%Number 0 TOTAL ADJUSTED STORM RAIN (in)4.59 Drywell Percolation Rate 0.00 cfs 0.00 cfm Unit Time Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft in/hr Total In Basin UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Loss Rate Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD MANUAL 24-HOUR STORM Basin Losses 44 660 11.00 2.0 0.367 0.353 0.312 0.01 0.06 51 51 14,442 1,504 51 0 0.00 302.00 45 675 11.25 1.9 0.349 0.347 0.297 0.00 0.01 5 5 14,438 1,504 5 0 0.00 302.00 46 690 11.50 1.9 0.349 0.342 0.297 0.01 0.03 23 23 14,439 1,504 23 0 0.00 302.00 47 705 11.75 1.7 0.312 0.337 0.265 0.05 0.18 163 163 14,454 1,506 163 0 0.00 302.00 48 720 12.00 1.8 0.330 0.332 0.281 0.05 0.19 173 173 14,455 1,506 173 0 0.00 302.00 49 735 12.25 2.5 0.459 0.327 0.390 0.13 0.51 460 460 14,485 1,509 460 0 0.00 302.00 50 750 12.50 2.6 0.477 0.322 0.406 0.16 0.60 541 541 14,494 1,510 541 0 0.00 302.00 51 765 12.75 2.8 0.514 0.317 0.437 0.20 0.76 686 686 14,509 1,511 686 0 0.00 302.00 52 780 13.00 2.9 0.532 0.313 0.453 0.22 0.85 767 767 14,518 1,512 767 0 0.00 302.00 53 795 13.25 3.4 0.624 0.308 0.531 0.32 1.23 1,103 1,103 14,553 1,516 1,103 0 0.00 302.00 54 810 13.50 3.4 0.624 0.303 0.531 0.32 1.24 1,120 1,120 14,555 1,516 1,120 0 0.00 302.00 55 825 13.75 2.3 0.422 0.299 0.359 0.12 0.48 431 431 14,482 1,509 431 0 0.00 302.00 56 840 14.00 2.3 0.422 0.294 0.359 0.13 0.50 447 447 14,484 1,509 447 0 0.00 302.00 57 855 14.25 2.7 0.496 0.290 0.421 0.21 0.80 719 719 14,513 1,512 719 0 0.00 302.00 58 870 14.50 2.6 0.477 0.285 0.406 0.19 0.74 670 670 14,508 1,511 670 0 0.00 302.00 59 885 14.75 2.6 0.477 0.281 0.406 0.20 0.76 685 685 14,509 1,511 685 0 0.00 302.00 60 900 15.00 2.5 0.459 0.277 0.390 0.18 0.71 636 636 14,504 1,511 636 0 0.00 302.00 61 915 15.25 2.4 0.441 0.272 0.375 0.17 0.65 587 587 14,499 1,510 587 0 0.00 302.00 62 930 15.50 2.3 0.422 0.268 0.359 0.15 0.60 538 538 14,494 1,510 538 0 0.00 302.00 63 945 15.75 1.9 0.349 0.264 0.297 0.08 0.33 296 296 14,468 1,507 296 0 0.00 302.00 64 960 16.00 1.9 0.349 0.260 0.297 0.09 0.34 310 310 14,470 1,507 310 0 0.00 302.00 65 975 16.25 0.4 0.073 0.256 0.062 0.01 0.04 38 38 14,441 1,504 38 0 0.00 302.00 66 990 16.50 0.4 0.073 0.252 0.062 0.01 0.04 38 38 14,441 1,504 38 0 0.00 302.00 67 1005 16.75 0.3 0.055 0.248 0.047 0.01 0.03 29 29 14,440 1,504 29 0 0.00 302.00 68 1020 17.00 0.3 0.055 0.245 0.047 0.01 0.03 29 29 14,440 1,504 29 0 0.00 302.00 69 1035 17.25 0.5 0.092 0.241 0.078 0.01 0.05 48 48 14,442 1,504 48 0 0.00 302.00 70 1050 17.50 0.5 0.092 0.237 0.078 0.01 0.05 48 48 14,442 1,504 48 0 0.00 302.00 71 1065 17.75 0.5 0.092 0.234 0.078 0.01 0.05 48 48 14,442 1,504 48 0 0.00 302.00 72 1080 18.00 0.4 0.073 0.230 0.062 0.01 0.04 38 38 14,441 1,504 38 0 0.00 302.00 73 1095 18.25 0.4 0.073 0.227 0.062 0.01 0.04 38 38 14,441 1,504 38 0 0.00 302.00 74 1110 18.50 0.4 0.073 0.224 0.062 0.01 0.04 38 38 14,441 1,504 38 0 0.00 302.00 75 1125 18.75 0.3 0.055 0.220 0.047 0.01 0.03 29 29 14,440 1,504 29 0 0.00 302.00 76 1140 19.00 0.2 0.037 0.217 0.031 0.01 0.02 19 19 14,439 1,504 19 0 0.00 302.00 77 1155 19.25 0.3 0.055 0.214 0.047 0.01 0.03 29 29 14,440 1,504 29 0 0.00 302.00 78 1170 19.50 0.4 0.073 0.211 0.062 0.01 0.04 38 38 14,441 1,504 38 0 0.00 302.00 79 1185 19.75 0.3 0.055 0.208 0.047 0.01 0.03 29 29 14,440 1,504 29 0 0.00 302.00 80 1200 20.00 0.2 0.037 0.205 0.031 0.01 0.02 19 19 14,439 1,504 19 0 0.00 302.00 81 1215 20.25 0.3 0.055 0.203 0.047 0.01 0.03 29 29 14,440 1,504 29 0 0.00 302.00 82 1230 20.50 0.3 0.055 0.200 0.047 0.01 0.03 29 29 14,440 1,504 29 0 0.00 302.00 83 1245 20.75 0.3 0.055 0.198 0.047 0.01 0.03 29 29 14,440 1,504 29 0 0.00 302.00 84 1260 21.00 0.2 0.037 0.195 0.031 0.01 0.02 19 19 14,439 1,504 19 0 0.00 302.00 85 1275 21.25 0.3 0.055 0.193 0.047 0.01 0.03 29 29 14,440 1,504 29 0 0.00 302.00 86 1290 21.50 0.2 0.037 0.191 0.031 0.01 0.02 19 19 14,439 1,504 19 0 0.00 302.00 Plate E-2.2 24-Hour Storm Page 11 of 13 PROJECT: Job No.:2636 BY:FOS DATE 1/9/24 DRAINAGE AREA-ACRES 3.84 VARIABLE LOSS RATE (AVG) IN/HR Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 15 Fm = Minimum value on loss curve (in/hr)0.18 LAG TIME - MINUTES 1.64 C 0.00326 Maxwell Drywells UNIT TIME-PERCENT OF LAG 915%Low Loss Rate (percent)85.00%Number 0 TOTAL ADJUSTED STORM RAIN (in)4.59 Drywell Percolation Rate 0.00 cfs 0.00 cfm Unit Time Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft in/hr Total In Basin UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Loss Rate Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD MANUAL 24-HOUR STORM Basin Losses 87 1305 21.75 0.3 0.055 0.189 0.047 0.01 0.03 29 29 14,440 1,504 29 0 0.00 302.00 88 1320 22.00 0.2 0.037 0.187 0.031 0.01 0.02 19 19 14,439 1,504 19 0 0.00 302.00 89 1335 22.25 0.3 0.055 0.185 0.047 0.01 0.03 29 29 14,440 1,504 29 0 0.00 302.00 90 1350 22.50 0.2 0.037 0.183 0.031 0.01 0.02 19 19 14,439 1,504 19 0 0.00 302.00 91 1365 22.75 0.2 0.037 0.181 0.031 0.01 0.02 19 19 14,439 1,504 19 0 0.00 302.00 92 1380 23.00 0.2 0.037 0.180 0.031 0.01 0.02 19 19 14,439 1,504 19 0 0.00 302.00 93 1395 23.25 0.2 0.037 0.179 0.031 0.01 0.02 19 19 14,439 1,504 19 0 0.00 302.00 94 1410 23.50 0.2 0.037 0.178 0.031 0.01 0.02 19 19 14,439 1,504 19 0 0.00 302.00 95 1425 23.75 0.2 0.037 0.177 0.031 0.01 0.02 19 19 14,439 1,504 19 0 0.00 302.00 96 1440 24.00 0.2 0.037 0.176 0.031 0.01 0.02 19 19 14,439 1,504 19 0 0.00 302.00 EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY TOTAL RAINFALL RAINFALL VOLUME SOIL LOSSES EFFECTIVE RAIN FLOOD VOLUME FLOOD VOLUME REQUIRED STORAGE REQUIRED STORAGE MAX WSEL PEAK FLOW RATE TOTAL BASIN LOSSES AVERAGE PERCOLATION RATE 14,730 cu-ft 10.23 cf/min 1.06 in 0.34 acft 14,730 cu-ft 0.00 acft 0 cu-ft 4.59 in 64,036 cu-ft 49,307 cu-ft 302.00 ft 1.24 cfs Plate E-2.2 24-Hour Storm Page 12 of 13 PROECT JOB No. BASIN DESIGNATION: BASIN CHARACTERISTICS CONTOUR ELEVATION INCR TOTAL INCR TOTAL INCR (ft)(ft)(sf)(sf)(cuft)(cuft)(acre-ft) 302 0 0 14,437 0 0 0.00 303 1 1 1,604 16,041 15,232 15,232 0.35 304 1 2 1,671 17,712 16,870 32,102 0.74 WHERE: TOTAL Retention Basin F BASIN VOLUME WORKSHEET DEPTH AREA VOLUME Del Webb Explore at Palm Desert 2636 ()()2121213 1 AAAAEEV++−= Basin Volume Worksheet Page 13 of 13 RJB 2 AMC II AREA SOIL TRIBUTARY AREAS ACRES LOW LOSS RI INFILTRATION IMPERVIOUS DESIG GROUP CONDITION NUMBER RATE PERCENT 4 A SF - DETACHED 22.864 D 32 0.74 0.50 9 A LANDSCAPING 6.242 D 32 0.74 0.10 2 A PAVING/HARDSCAPE 14.162 D 32 0.74 1.00 1 A RECREATION CENTER 1.093 D 32 0.74 0.60 3,500 ft 1,750 ft 300.8 ft ELEVATION OF CONCENTRATION POINT 280.0 ft 0.02 100 LOW LOSS RATE (Storm Events > 10 Years)85% POINT RAIN FROM NOAA ATLAS 14 1-HOUR 1.57 in 3-HOUR 2.27 in 6-HOUR 2.98 in 24-HOUR 4.59 in BASIN CHARACTERISTICS:ELEVATION AREA 269.0 ft 34,231 sf 270.0 ft 37,586 sf 271.0 ft 40,827 sf 272.0 ft 43,508 sf 273.0 ft 46,245 sf 274.0 ft 49,038 sf 275.0 ft 51,862 sf PERCOLATION RATE (in/hr)5.0 in/hr DRYWELL DATA NUMBER USED 50 PERCOLATION RATE LOWEST FLOWLINE ELEVATION LOWEST PAD ELEVATION PROJECT NUMBER CONCENTRATION POINT DESIGNATION 2636 Retention Basin G AMC NUMBER RCFCD SYNTHETIC UNIT HYDROGRAPH - SHORTCUT METHOD DATA INPUT SHEET WORKSHEET PREPARED BY: PROJECT NAME DATE January 9, 2024 Del Webb Explore at Palm Desert LENGTH OF WATERCOURSE (L) AREA DESIGNATION ELEVATION OF HEADWATER AVERAGE MANNINGS 'N' VALUE STORM FREQUENCY (YEAR) LENGTH TO POINT OPPOSITE CENTROID (Lca) Low Loss Conditions: X=Existing; D=Developed; BS=Retention DA-G Data Input Sheet Page 1 of 13 PROJECT: Job No.: BY:DATE:1/9/24 [1] AMC II [2] FREQUENCY-YEARS 100 FROM NOAA ATLAS 14 [3] STORM DURATION:Point Rain 1-HOUR 1.57 in 3-HOUR 2.27 in 6-HOUR 2.98 in 24-HOUR 4.59 in STORM DURATION 1-HOUR 3-HOUR 6-HOUR 24-HOUR RAINFALL VOLUME (cu-ft)252,819 365,541 479,873 739,133 SOIL LOSSES (cu-ft)54,193 158,828 269,009 558,299 EFFECTIVE RAIN (in)1.23 1.28 1.31 1.12 FLOOD VOLUME (cu-ft)198,626 206,713 210,864 180,833 (acre-ft)4.56 4.75 4.84 4.15 REQUIRED STORAGE (cu-ft)182,055 163,153 151,770 60,831 (acre-ft)4.18 3.75 3.48 1.40 FACTOR OF SAFETY 1.43 1.59 1.71 4.28 STORAGE PROVIDED (cu-ft) (acre-ft) PEAK FLOW (cfs)n/a 84.86 74.52 14.96 MAXIMUM WSEL (ft)273.42 273.02 272.77 270.64 DEPTH (ft)4.42 4.02 3.77 1.64 DIFFERENCE (ft) DIFFERENCE (ft) ESTIMATED TIME TO DEWATER BASIN Based on Total Flood Volume & Average Percolation Rate (days)0.5 0.6 0.8 1.0 Retention Basin G DA-G Del Webb Explore at Palm Desert [10] H-FEET [9] ELEVATION OF CONCENTRATION POINT 44.361 PHYSICAL DATA [1] CONCENTRATION POINT HYDROLOGY MANUAL BASIC DATA CALCULATION FORM 2636 RJB RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD [2] AREA DESIGNATION [3] AREA - ACRES [4] L-FEET [5] L-MILES 3500 0.663 [13] L*LCA/S^0.5 5.60 [11] S-FEET/MILE [6] La-FEET [7] La-MILES [8] ELEVATION OF HEADWATER 0.039 1750.00 [12] S^0.5 0.331 31.4 300.8 280 20.8 0.02 [17] 100% OF LAG-MINUTES 8.4 8.4 [14] AVERAGE MANNINGS 'N' [15] LAG TIME-HOURS 0.14 [16] LAG TIME-MINUTES [18] 200% OF LAG-MINUTES RAINFALL DATA 16.8 NOTE: PEAK FLOW FOR THE 1-HOUR STORM IS NOT REPRESENTATIVE. PER RCFCD PEAK DISCHARGES FROM THE 3-HOUR STORM SHOULD NORMALLY COMPARE WELL WITH RATIONAL PEAKS. LOWEST PAD ELEVATION LOWEST FLOWLINE ELEVATION STORM EVENT SUMMARY 260,199 5.97 Plate E-2.1 Page 2 of 13 PROJECT: Job No.: BY:DATE:1/9/24 MAX LOW LOW MIN SOIL RI PERVIOUS DECIMAL ADJUSTED AREA AREA AVERAGE LOSS LOSS RATE AVERAGE GROUP NUMBER AREA PERCENT INFILTRATION WEIGHTED ADJUSTED CONDITION PER ADJUSTED INFILTRATION OF AREA RATE AVERAGE INFILTRATION RCFC/2322 INFILTRATION RATE IMPERVIOUS RATE RATE (in/hr)(in/hr)(in/hr) [Plate C-1][Plate E-6.1][Plate E-6.2][Plate E-6.3] A 32 0.74 50%0.41 22.864 0.515 0.2098 DEVELOPED 0.5000 0.2577 A 32 0.74 10%0.67 6.242 0.141 0.0948 DEVELOPED 0.8200 0.1154 A 32 0.74 100%0.07 14.162 0.319 0.0236 DEVELOPED 0.1000 0.0319 A 32 0.74 60%0.34 1.093 0.025 0.0084 DEVELOPED 0.4200 0.0103 SUM 44.361 SUM 0.3365 0.4154 VARIABLE LOSS RATE CURVE (24-HOUR STORM ONLY) Fm=0.168267803 NOTE: Low loss rates established per RCFC/2322 (Dated: May-30-95) C=0.00312 For 10 Year Storms or Less Ft=C(24-(T/60))^1.55+Fm =0.00312 0.17 in/hr Undeveloped Condition: Low Loss = 90% CONSTANT LOSS RATE (3 & 6 HOUR STORMS)=0.3365 Developed Condition: Low Loss = 0.9 - (0.8 * %impervious) LOW LOSS RATE =0.8500 Basin Site: Low Loss = 10% Where:For 100 Year Storm - Low Loss should be between 80% & 90% T=Time in minutes. To get an average value for each unit time period, Use T=1/2 the unit time for the first time period,of the Rainfall Rate T=1 1/2 unit time for the second period, etc. AVERAGE ADJUSTED LOSS RATE RCFC & WCD HYDROLOGY MANUAL SYNTHETIC UNIT HYDROGRAPH METHOD BASIC DATA CALCULATION FORM Del Webb Explore at Palm Desert RJB 2636 AMC II (24-(T/60))^1.55 + LAND USE SF - DETACHED LANDSCAPING PAVING/HARDSCAPE RECREATION CENTER Plate E-2.1 Page 3 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 44.36 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 8.41 Maxwell Drywells UNIT TIME-PERCENT OF LAG 59.4 Number 50 TOTAL ADJUSTED STORM RAIN-INCHES 1.57 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE-in/hr 0.34 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 5 0.08 3.6 0.68 0.34 0.58 0.34 15.28 4,585 4,585 34,660 1,203 1,203 3,382 0.08 269.09 2 10 0.17 4.2 0.79 0.34 0.67 0.45 20.34 6,102 9,484 35,117 1,219 1,219 8,265 0.19 269.23 3 15 0.25 4.4 0.83 0.34 0.70 0.49 22.03 6,608 14,873 35,621 1,237 1,237 13,636 0.31 269.38 4 20 0.33 4.6 0.87 0.34 0.74 0.53 23.71 7,114 20,750 36,170 1,256 1,256 19,494 0.45 269.54 5 25 0.42 5.0 0.94 0.34 0.80 0.61 27.08 8,125 27,619 36,812 1,278 1,278 26,340 0.60 269.73 6 30 0.50 5.6 1.06 0.34 0.90 0.72 32.14 9,642 35,982 37,593 1,305 1,305 34,677 0.80 269.97 7 35 0.58 6.4 1.21 0.34 1.02 0.87 38.88 11,664 46,341 38,450 1,335 1,335 45,006 1.03 270.23 8 40 0.67 8.1 1.53 0.34 1.30 1.19 53.21 15,962 60,968 39,659 1,377 1,377 59,591 1.37 270.60 9 45 0.75 13.1 2.47 0.34 2.10 2.13 95.34 28,603 88,195 41,660 1,447 1,447 86,748 1.99 271.28 10 50 0.83 34.5 6.50 0.34 5.52 6.16 275.69 82,706 169,454 46,675 1,621 1,621 167,834 3.85 273.12 11 55 0.92 6.7 1.26 0.34 1.07 0.93 41.41 12,423 180,257 47,308 1,643 1,643 178,614 4.10 273.35 12 60 1.00 3.8 0.72 0.34 0.61 0.38 16.97 5,091 183,705 47,511 1,650 1,650 182,055 4.18 273.42 TOTAL RAINFALL 1.57 in RAINFALL VOLUME 252,819 cu-ft SOIL LOSSES 54,193 cu-ft EFFECTIVE RAIN 1.23 in FLOOD VOLUME 4.56 acft FLOOD VOLUME 198,626 cu-ft REQUIRED STORAGE 4.18 REQUIRED STORAGE 182,055 cu-ft MAX WSEL 273.42 ft PEAK FLOW RATE 275.69 cfs TOTAL BASIN LOSSES 16,571 cu-ft AVERAGE PERCOLATION RATE 276.18 cf/min Del Webb Explore at Palm DesertRCFC & WCD HYDROLOGY MANUAL SYNTHETIC UNIT HYDROGRAPH METHOD SHORTCUT METHOD 1-HOUR STORM EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Total In Basin in/hr Time Loss Rate Basin Losses Plate E-2.2 1-Hour Storm Page 4 of 13 PROJECT: Job No.:2636 BY:RJB DATE DRAINAGE AREA-ACRES 44.36 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 8.41 Maxwell Drywells UNIT TIME-PERCENT OF LAG 59.4 Number 50 TOTAL ADJUSTED STORM RAIN (in)2.27 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.34 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 5 0.08 1.3 0.35 0.34 0.30 0.02 0.79 236 236 34,253 1,189 236 0 0.00 269.00 2 10 0.17 1.3 0.35 0.34 0.30 0.02 0.79 236 236 34,253 1,189 236 0 0.00 269.00 3 15 0.25 1.1 0.30 0.34 0.25 0.04 2.01 603 603 34,287 1,191 603 0 0.00 269.00 4 20 0.33 1.5 0.41 0.34 0.35 0.07 3.22 967 967 34,321 1,192 967 0 0.00 269.00 5 25 0.42 1.5 0.41 0.34 0.35 0.07 3.22 967 967 34,321 1,192 967 0 0.00 269.00 6 30 0.50 1.8 0.49 0.34 0.42 0.15 6.88 2,064 2,064 34,424 1,195 1,195 868 0.02 269.02 7 35 0.58 1.5 0.41 0.34 0.35 0.07 3.22 967 1,835 34,403 1,195 1,195 641 0.01 269.02 8 40 0.67 1.8 0.49 0.34 0.42 0.15 6.88 2,064 2,705 34,484 1,197 1,197 1,507 0.03 269.04 9 45 0.75 1.8 0.49 0.34 0.42 0.15 6.88 2,064 3,571 34,565 1,200 1,200 2,371 0.05 269.07 10 50 0.83 1.5 0.41 0.34 0.35 0.07 3.22 967 3,338 34,543 1,199 1,199 2,138 0.05 269.06 11 55 0.92 1.6 0.44 0.34 0.37 0.10 4.44 1,333 3,471 34,555 1,200 1,200 2,271 0.05 269.06 12 60 1.00 1.8 0.49 0.34 0.42 0.15 6.88 2,064 4,335 34,636 1,203 1,203 3,132 0.07 269.09 13 65 1.08 2.2 0.60 0.34 0.51 0.26 11.75 3,526 6,658 34,853 1,210 1,210 5,448 0.13 269.15 14 70 1.17 2.2 0.60 0.34 0.51 0.26 11.75 3,526 8,974 35,070 1,218 1,218 7,756 0.18 269.22 15 75 1.25 2.2 0.60 0.34 0.51 0.26 11.75 3,526 11,282 35,285 1,225 1,225 10,057 0.23 269.28 16 80 1.33 2.0 0.54 0.34 0.46 0.21 9.32 2,795 12,851 35,432 1,230 1,230 11,621 0.27 269.32 17 85 1.42 2.6 0.71 0.34 0.60 0.37 16.63 4,988 16,609 35,783 1,242 1,242 15,367 0.35 269.43 18 90 1.50 2.7 0.74 0.34 0.63 0.40 17.85 5,354 20,720 36,168 1,256 1,256 19,464 0.45 269.54 19 95 1.58 2.4 0.65 0.34 0.56 0.32 14.19 4,257 23,721 36,448 1,266 1,266 22,456 0.52 269.63 20 100 1.67 2.7 0.74 0.34 0.63 0.40 17.85 5,354 27,809 36,830 1,279 1,279 26,530 0.61 269.74 21 105 1.75 3.3 0.90 0.34 0.76 0.56 25.16 7,547 34,077 37,416 1,299 1,299 32,778 0.75 269.91 22 110 1.83 3.1 0.84 0.34 0.72 0.51 22.72 6,816 39,594 37,892 1,316 1,316 38,278 0.88 270.06 23 115 1.92 2.9 0.79 0.34 0.67 0.45 20.28 6,085 44,363 38,286 1,329 1,329 43,033 0.99 270.18 24 120 2.00 3.0 0.82 0.34 0.69 0.48 21.50 6,450 49,483 38,710 1,344 1,344 48,139 1.11 270.31 25 125 2.08 3.1 0.84 0.34 0.72 0.51 22.72 6,816 54,955 39,162 1,360 1,360 53,595 1.23 270.45 Total In Basin in/hr MANUAL 3-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Loss Rate Basin Losses RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Plate E-2.2 3-Hour Storm Page 5 of 13 PROJECT: Job No.:2636 BY:RJB DATE DRAINAGE AREA-ACRES 44.36 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 8.41 Maxwell Drywells UNIT TIME-PERCENT OF LAG 59.4 Number 50 TOTAL ADJUSTED STORM RAIN (in)2.27 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.34 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft Total In Basin in/hr MANUAL 3-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Loss Rate Basin Losses RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD 26 130 2.17 4.2 1.14 0.34 0.97 0.81 36.12 10,837 64,432 39,946 1,387 1,387 63,045 1.45 270.69 27 135 2.25 5.0 1.36 0.34 1.16 1.03 45.87 13,761 76,806 40,936 1,421 1,421 75,384 1.73 271.01 28 140 2.33 3.5 0.95 0.34 0.81 0.62 27.59 8,278 83,662 41,372 1,437 1,437 82,226 1.89 271.17 29 145 2.42 6.8 1.85 0.34 1.57 1.52 67.80 20,341 102,566 42,574 1,478 1,478 101,088 2.32 271.62 30 150 2.50 7.3 1.99 0.34 1.69 1.65 73.89 22,168 123,257 43,874 1,523 1,523 121,733 2.79 272.10 31 155 2.58 8.2 2.23 0.34 1.90 1.90 84.86 25,458 147,191 45,334 1,574 1,574 145,617 3.34 272.63 32 160 2.67 5.9 1.61 0.34 1.37 1.27 56.84 17,051 162,668 46,277 1,607 1,607 161,061 3.70 272.98 33 165 2.75 2.0 0.54 0.34 0.46 0.21 9.32 2,795 163,856 46,347 1,609 1,609 162,247 3.72 273.00 34 170 2.83 1.8 0.49 0.34 0.42 0.15 6.88 2,064 164,310 46,373 1,610 1,610 162,700 3.74 273.01 35 175 2.92 1.8 0.49 0.34 0.42 0.15 6.88 2,064 164,764 46,400 1,611 1,611 163,153 3.75 273.02 36 180 3.00 0.6 0.16 0.34 0.14 0.02 1.10 329 163,482 46,325 1,609 1,609 161,873 3.72 272.99 TOTAL RAIN RAINFALL VOLUME SOIL LOSSES EFFECTIVE RAIN FLOOD VOLUME FLOOD VOLUME REQUIRED STORAGE REQUIRED STORAGE MAX WSEL PEAK FLOW RATE TOTAL BASIN LOSSES AVERAGE PERCOLATION RATE 158,828 cu-ft 2.27 in 365,541 cu-ft 273.02 ft 84.86 cfs 44,839 cu-ft 249.11 cf/min 1.28 in 4.75 acft 206,713 cu-ft 3.75 acft 163,153 cu-ft EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY Plate E-2.2 3-Hour Storm Page 6 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 44.36 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 8.41 Maxwell Drywells UNIT TIME-PERCENT OF LAG 59.4 Number 50 TOTAL ADJUSTED STORM RAIN (in)2.98 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.34 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 5 0.08 0.5 0.18 0.34 0.15 0.03 1.20 360 360 34,265 1,190 360 0 0.00 269.00 2 10 0.17 0.6 0.21 0.34 0.18 0.03 1.44 432 432 34,271 1,190 432 0 0.00 269.00 3 15 0.25 0.6 0.21 0.34 0.18 0.03 1.44 432 432 34,271 1,190 432 0 0.00 269.00 4 20 0.33 0.6 0.21 0.34 0.18 0.03 1.44 432 432 34,271 1,190 432 0 0.00 269.00 5 25 0.42 0.6 0.21 0.34 0.18 0.03 1.44 432 432 34,271 1,190 432 0 0.00 269.00 6 30 0.50 0.7 0.25 0.34 0.21 0.04 1.68 504 504 34,278 1,190 504 0 0.00 269.00 7 35 0.58 0.7 0.25 0.34 0.21 0.04 1.68 504 504 34,278 1,190 504 0 0.00 269.00 8 40 0.67 0.7 0.25 0.34 0.21 0.04 1.68 504 504 34,278 1,190 504 0 0.00 269.00 9 45 0.75 0.7 0.25 0.34 0.21 0.04 1.68 504 504 34,278 1,190 504 0 0.00 269.00 10 50 0.83 0.7 0.25 0.34 0.21 0.04 1.68 504 504 34,278 1,190 504 0 0.00 269.00 11 55 0.92 0.7 0.25 0.34 0.21 0.04 1.68 504 504 34,278 1,190 504 0 0.00 269.00 12 60 1.00 0.8 0.29 0.34 0.24 0.04 1.92 576 576 34,285 1,190 576 0 0.00 269.00 13 65 1.08 0.8 0.29 0.34 0.24 0.04 1.92 576 576 34,285 1,190 576 0 0.00 269.00 14 70 1.17 0.8 0.29 0.34 0.24 0.04 1.92 576 576 34,285 1,190 576 0 0.00 269.00 15 75 1.25 0.8 0.29 0.34 0.24 0.04 1.92 576 576 34,285 1,190 576 0 0.00 269.00 16 80 1.33 0.8 0.29 0.34 0.24 0.04 1.92 576 576 34,285 1,190 576 0 0.00 269.00 17 85 1.42 0.8 0.29 0.34 0.24 0.04 1.92 576 576 34,285 1,190 576 0 0.00 269.00 18 90 1.50 0.8 0.29 0.34 0.24 0.04 1.92 576 576 34,285 1,190 576 0 0.00 269.00 19 95 1.58 0.8 0.29 0.34 0.24 0.04 1.92 576 576 34,285 1,190 576 0 0.00 269.00 20 100 1.67 0.8 0.29 0.34 0.24 0.04 1.92 576 576 34,285 1,190 576 0 0.00 269.00 21 105 1.75 0.8 0.29 0.34 0.24 0.04 1.92 576 576 34,285 1,190 576 0 0.00 269.00 22 110 1.83 0.8 0.29 0.34 0.24 0.04 1.92 576 576 34,285 1,190 576 0 0.00 269.00 23 115 1.92 0.8 0.29 0.34 0.24 0.04 1.92 576 576 34,285 1,190 576 0 0.00 269.00 24 120 2.00 0.9 0.32 0.34 0.27 0.05 2.16 648 648 34,292 1,191 648 0 0.00 269.00 Loss Rate RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 6-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Basin Losses Plate E-2.2 6-Hour Storm Page 7 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 44.36 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 8.41 Maxwell Drywells UNIT TIME-PERCENT OF LAG 59.4 Number 50 TOTAL ADJUSTED STORM RAIN (in)2.98 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.34 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft Loss Rate RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 6-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Basin Losses 25 125 2.08 0.8 0.29 0.34 0.24 0.04 1.92 576 576 34,285 1,190 576 0 0.00 269.00 26 130 2.17 0.9 0.32 0.34 0.27 0.05 2.16 648 648 34,292 1,191 648 0 0.00 269.00 27 135 2.25 0.9 0.32 0.34 0.27 0.05 2.16 648 648 34,292 1,191 648 0 0.00 269.00 28 140 2.33 0.9 0.32 0.34 0.27 0.05 2.16 648 648 34,292 1,191 648 0 0.00 269.00 29 145 2.42 0.9 0.32 0.34 0.27 0.05 2.16 648 648 34,292 1,191 648 0 0.00 269.00 30 150 2.50 0.9 0.32 0.34 0.27 0.05 2.16 648 648 34,292 1,191 648 0 0.00 269.00 31 155 2.58 0.9 0.32 0.34 0.27 0.05 2.16 648 648 34,292 1,191 648 0 0.00 269.00 32 160 2.67 0.9 0.32 0.34 0.27 0.05 2.16 648 648 34,292 1,191 648 0 0.00 269.00 33 165 2.75 1.0 0.36 0.34 0.30 0.02 0.94 283 283 34,257 1,189 283 0 0.00 269.00 34 170 2.83 1.0 0.36 0.34 0.30 0.02 0.94 283 283 34,257 1,189 283 0 0.00 269.00 35 175 2.92 1.0 0.36 0.34 0.30 0.02 0.94 283 283 34,257 1,189 283 0 0.00 269.00 36 180 3.00 1.0 0.36 0.34 0.30 0.02 0.94 283 283 34,257 1,189 283 0 0.00 269.00 37 185 3.08 1.0 0.36 0.34 0.30 0.02 0.94 283 283 34,257 1,189 283 0 0.00 269.00 38 190 3.17 1.1 0.39 0.34 0.33 0.06 2.54 763 763 34,302 1,191 763 0 0.00 269.00 39 195 3.25 1.1 0.39 0.34 0.33 0.06 2.54 763 763 34,302 1,191 763 0 0.00 269.00 40 200 3.33 1.1 0.39 0.34 0.33 0.06 2.54 763 763 34,302 1,191 763 0 0.00 269.00 41 205 3.42 1.2 0.43 0.34 0.36 0.09 4.14 1,242 1,242 34,347 1,193 1,193 50 0.00 269.00 42 210 3.50 1.3 0.46 0.34 0.40 0.13 5.74 1,722 1,772 34,397 1,194 1,194 578 0.01 269.02 43 215 3.58 1.4 0.50 0.34 0.43 0.16 7.34 2,202 2,780 34,491 1,198 1,198 1,582 0.04 269.04 44 220 3.67 1.4 0.50 0.34 0.43 0.16 7.34 2,202 3,784 34,585 1,201 1,201 2,584 0.06 269.07 45 225 3.75 1.5 0.54 0.34 0.46 0.20 8.94 2,682 5,266 34,723 1,206 1,206 4,060 0.09 269.11 46 230 3.83 1.5 0.54 0.34 0.46 0.20 8.94 2,682 6,742 34,861 1,210 1,210 5,532 0.13 269.15 47 235 3.92 1.6 0.57 0.34 0.49 0.24 10.54 3,162 8,693 35,044 1,217 1,217 7,477 0.17 269.21 48 240 4.00 1.6 0.57 0.34 0.49 0.24 10.54 3,162 10,639 35,225 1,223 1,223 9,415 0.22 269.26 49 245 4.08 1.7 0.61 0.34 0.52 0.27 12.14 3,642 13,057 35,451 1,231 1,231 11,826 0.27 269.33 50 250 4.17 1.8 0.64 0.34 0.55 0.31 13.74 4,122 15,948 35,722 1,240 1,240 14,708 0.34 269.41 Plate E-2.2 6-Hour Storm Page 8 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 44.36 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 8.41 Maxwell Drywells UNIT TIME-PERCENT OF LAG 59.4 Number 50 TOTAL ADJUSTED STORM RAIN (in)2.98 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.34 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft Loss Rate RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 6-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Basin Losses 51 255 4.25 1.9 0.68 0.34 0.58 0.34 15.34 4,602 19,309 36,036 1,251 1,251 18,058 0.41 269.50 52 260 4.33 2.0 0.72 0.34 0.61 0.38 16.94 5,081 23,139 36,394 1,264 1,264 21,876 0.50 269.61 53 265 4.42 2.1 0.75 0.34 0.64 0.41 18.54 5,561 27,437 36,795 1,278 1,278 26,159 0.60 269.73 54 270 4.50 2.1 0.75 0.34 0.64 0.41 18.54 5,561 31,721 37,196 1,292 1,292 30,429 0.70 269.85 55 275 4.58 2.2 0.79 0.34 0.67 0.45 20.14 6,041 36,470 37,634 1,307 1,307 35,163 0.81 269.98 56 280 4.67 2.3 0.82 0.34 0.70 0.49 21.74 6,521 41,684 38,065 1,322 1,322 40,363 0.93 270.11 57 285 4.75 2.4 0.86 0.34 0.73 0.52 23.34 7,001 47,364 38,534 1,338 1,338 46,026 1.06 270.26 58 290 4.83 2.4 0.86 0.34 0.73 0.52 23.34 7,001 53,027 39,003 1,354 1,354 51,672 1.19 270.40 59 295 4.92 2.5 0.89 0.34 0.76 0.56 24.94 7,481 59,153 39,509 1,372 1,372 57,781 1.33 270.56 60 300 5.00 2.6 0.93 0.34 0.79 0.59 26.54 7,961 65,742 40,054 1,391 1,391 64,351 1.48 270.73 61 305 5.08 3.1 1.11 0.34 0.94 0.77 34.53 10,360 74,711 40,796 1,417 1,417 73,295 1.68 270.95 62 310 5.17 3.6 1.29 0.34 1.09 0.95 42.53 12,759 86,054 41,524 1,442 1,442 84,612 1.94 271.23 63 315 5.25 3.9 1.39 0.34 1.19 1.06 47.33 14,199 98,811 42,335 1,470 1,470 97,341 2.23 271.53 64 320 5.33 4.2 1.50 0.34 1.28 1.17 52.13 15,639 112,980 43,236 1,501 1,501 111,478 2.56 271.86 65 325 5.42 4.7 1.68 0.34 1.43 1.34 60.13 18,038 129,516 44,256 1,537 1,537 127,980 2.94 272.24 66 330 5.50 5.6 2.00 0.34 1.70 1.67 74.52 22,357 150,336 45,526 1,581 1,581 148,756 3.41 272.70 67 335 5.58 1.9 0.68 0.34 0.58 0.34 15.34 4,602 153,357 45,710 1,587 1,587 151,770 3.48 272.77 68 340 5.67 0.9 0.32 0.34 0.27 0.05 2.16 648 152,418 45,653 1,585 1,585 150,833 3.46 272.75 69 345 5.75 0.6 0.21 0.34 0.18 0.03 1.44 432 151,265 45,583 1,583 1,583 149,682 3.44 272.72 70 350 5.83 0.5 0.18 0.34 0.15 0.03 1.20 360 150,042 45,508 1,580 1,580 148,462 3.41 272.70 71 355 5.92 0.3 0.11 0.34 0.09 0.02 0.72 216 148,678 45,425 1,577 1,577 147,100 3.38 272.67 72 360 6.00 0.2 0.07 0.34 0.06 0.01 0.48 144 147,244 45,338 1,574 1,574 145,670 3.34 272.63 TOTAL RAINFALL RAINFALL VOLUME SOIL LOSSES EFFECTIVE RAIN FLOOD VOLUME FLOOD VOLUME REQUIRED STORAGE REQUIRED STORAGE MAX WSEL PEAK FLOW RATE TOTAL BASIN LOSSES AVERAGE PERCOLATION RATE 479,873 cu-ft 2.98 in 269,009 cu-ft 272.77 ft 74.52 cfs 181.09 cf/min 65,194 cu-ft 1.31 in 4.84 acft 210,864 cu-ft 3.48 acft 151,770 cu-ft EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY Plate E-2.2 6-Hour Storm Page 9 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 44.36 VARIABLE LOSS RATE (AVG) IN/HR Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 15 Fm = Minimum value on loss curve (in/hr)0.17 LAG TIME - MINUTES 8.41 C 0.00312 Maxwell Drywells UNIT TIME-PERCENT OF LAG 178%Low Loss Rate (percent)85.00%Number 50 TOTAL ADJUSTED STORM RAIN (in)4.59 Drywell Percolation Rate 0.00 cfs 0.00 cfm Unit Time Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 15 0.25 0.2 0.037 0.594 0.031 0.01 0.25 222 222 34,252 3,568 222 0 0.00 269.00 2 30 0.50 0.3 0.055 0.587 0.047 0.01 0.37 333 333 34,262 3,569 333 0 0.00 269.00 3 45 0.75 0.3 0.055 0.581 0.047 0.01 0.37 333 333 34,262 3,569 333 0 0.00 269.00 4 60 1.00 0.4 0.073 0.574 0.062 0.01 0.49 443 443 34,272 3,570 443 0 0.00 269.00 5 75 1.25 0.3 0.055 0.567 0.047 0.01 0.37 333 333 34,262 3,569 333 0 0.00 269.00 6 90 1.50 0.3 0.055 0.560 0.047 0.01 0.37 333 333 34,262 3,569 333 0 0.00 269.00 7 105 1.75 0.3 0.055 0.554 0.047 0.01 0.37 333 333 34,262 3,569 333 0 0.00 269.00 8 120 2.00 0.4 0.073 0.547 0.062 0.01 0.49 443 443 34,272 3,570 443 0 0.00 269.00 9 135 2.25 0.4 0.073 0.540 0.062 0.01 0.49 443 443 34,272 3,570 443 0 0.00 269.00 10 150 2.50 0.4 0.073 0.534 0.062 0.01 0.49 443 443 34,272 3,570 443 0 0.00 269.00 11 165 2.75 0.5 0.092 0.527 0.078 0.01 0.62 554 554 34,283 3,571 554 0 0.00 269.00 12 180 3.00 0.5 0.092 0.521 0.078 0.01 0.62 554 554 34,283 3,571 554 0 0.00 269.00 13 195 3.25 0.5 0.092 0.514 0.078 0.01 0.62 554 554 34,283 3,571 554 0 0.00 269.00 14 210 3.50 0.5 0.092 0.508 0.078 0.01 0.62 554 554 34,283 3,571 554 0 0.00 269.00 15 225 3.75 0.5 0.092 0.501 0.078 0.01 0.62 554 554 34,283 3,571 554 0 0.00 269.00 16 240 4.00 0.6 0.110 0.495 0.094 0.02 0.74 665 665 34,293 3,572 665 0 0.00 269.00 17 255 4.25 0.6 0.110 0.489 0.094 0.02 0.74 665 665 34,293 3,572 665 0 0.00 269.00 18 270 4.50 0.7 0.129 0.483 0.109 0.02 0.86 776 776 34,304 3,573 776 0 0.00 269.00 19 285 4.75 0.7 0.129 0.476 0.109 0.02 0.86 776 776 34,304 3,573 776 0 0.00 269.00 20 300 5.00 0.8 0.147 0.470 0.125 0.02 0.99 887 887 34,314 3,574 887 0 0.00 269.00 21 315 5.25 0.6 0.110 0.464 0.094 0.02 0.74 665 665 34,293 3,572 665 0 0.00 269.00 22 330 5.50 0.7 0.129 0.458 0.109 0.02 0.86 776 776 34,304 3,573 776 0 0.00 269.00 23 345 5.75 0.8 0.147 0.452 0.125 0.02 0.99 887 887 34,314 3,574 887 0 0.00 269.00 24 360 6.00 0.8 0.147 0.446 0.125 0.02 0.99 887 887 34,314 3,574 887 0 0.00 269.00 25 375 6.25 0.9 0.165 0.440 0.140 0.02 1.11 998 998 34,324 3,575 998 0 0.00 269.00 26 390 6.50 0.9 0.165 0.434 0.140 0.02 1.11 998 998 34,324 3,575 998 0 0.00 269.00 27 405 6.75 1.0 0.184 0.429 0.156 0.03 1.23 1,109 1,109 34,335 3,577 1,109 0 0.00 269.00 28 420 7.00 1.0 0.184 0.423 0.156 0.03 1.23 1,109 1,109 34,335 3,577 1,109 0 0.00 269.00 29 435 7.25 1.0 0.184 0.417 0.156 0.03 1.23 1,109 1,109 34,335 3,577 1,109 0 0.00 269.00 30 450 7.50 1.1 0.202 0.411 0.172 0.03 1.36 1,220 1,220 34,345 3,578 1,220 0 0.00 269.00 31 465 7.75 1.2 0.220 0.406 0.187 0.03 1.48 1,330 1,330 34,355 3,579 1,330 0 0.00 269.00 32 480 8.00 1.3 0.239 0.400 0.203 0.04 1.60 1,441 1,441 34,366 3,580 1,441 0 0.00 269.00 33 495 8.25 1.5 0.275 0.395 0.234 0.04 1.85 1,663 1,663 34,386 3,582 1,663 0 0.00 269.00 34 510 8.50 1.5 0.275 0.389 0.234 0.04 1.85 1,663 1,663 34,386 3,582 1,663 0 0.00 269.00 35 525 8.75 1.6 0.294 0.384 0.250 0.04 1.97 1,774 1,774 34,397 3,583 1,774 0 0.00 269.00 36 540 9.00 1.7 0.312 0.378 0.265 0.05 2.09 1,885 1,885 34,407 3,584 1,885 0 0.00 269.00 37 555 9.25 1.9 0.349 0.373 0.297 0.05 2.34 2,107 2,107 34,428 3,586 2,107 0 0.00 269.00 38 570 9.50 2.0 0.367 0.368 0.312 0.06 2.46 2,217 2,217 34,438 3,587 2,217 0 0.00 269.00 39 585 9.75 2.1 0.386 0.362 0.328 0.02 1.04 936 936 34,318 3,575 936 0 0.00 269.00 40 600 10.00 2.2 0.404 0.357 0.343 0.05 2.09 1,885 1,885 34,407 3,584 1,885 0 0.00 269.00 41 615 10.25 1.5 0.275 0.352 0.234 0.04 1.85 1,663 1,663 34,386 3,582 1,663 0 0.00 269.00 42 630 10.50 1.5 0.275 0.347 0.234 0.04 1.85 1,663 1,663 34,386 3,582 1,663 0 0.00 269.00 43 645 10.75 2.0 0.367 0.342 0.312 0.03 1.14 1,023 1,023 34,327 3,576 1,023 0 0.00 269.00 RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Loss Rate Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD MANUAL 24-HOUR STORM Basin Losses in/hr Total In Basin UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Plate E-2.2 24-Hour Storm Page 10 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 44.36 VARIABLE LOSS RATE (AVG) IN/HR Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 15 Fm = Minimum value on loss curve (in/hr)0.17 LAG TIME - MINUTES 8.41 C 0.00312 Maxwell Drywells UNIT TIME-PERCENT OF LAG 178%Low Loss Rate (percent)85.00%Number 50 TOTAL ADJUSTED STORM RAIN (in)4.59 Drywell Percolation Rate 0.00 cfs 0.00 cfm Unit Time Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Loss Rate Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD MANUAL 24-HOUR STORM Basin Losses in/hr Total In Basin UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM 44 660 11.00 2.0 0.367 0.337 0.312 0.03 1.36 1,224 1,224 34,345 3,578 1,224 0 0.00 269.00 45 675 11.25 1.9 0.349 0.332 0.297 0.02 0.76 684 684 34,295 3,572 684 0 0.00 269.00 46 690 11.50 1.9 0.349 0.327 0.297 0.02 0.98 881 881 34,313 3,574 881 0 0.00 269.00 47 705 11.75 1.7 0.312 0.322 0.265 0.05 2.09 1,885 1,885 34,407 3,584 1,885 0 0.00 269.00 48 720 12.00 1.8 0.330 0.317 0.281 0.01 0.59 530 530 34,281 3,571 530 0 0.00 269.00 49 735 12.25 2.5 0.459 0.313 0.390 0.15 6.55 5,895 5,895 34,782 3,623 3,623 2,272 0.05 269.06 50 750 12.50 2.6 0.477 0.308 0.406 0.17 7.58 6,822 9,094 35,081 3,654 3,654 5,440 0.12 269.15 51 765 12.75 2.8 0.514 0.303 0.437 0.21 9.43 8,487 13,927 35,533 3,701 3,701 10,225 0.23 269.28 52 780 13.00 2.9 0.532 0.299 0.453 0.23 10.46 9,410 19,635 36,066 3,757 3,757 15,878 0.36 269.44 53 795 13.25 3.4 0.624 0.294 0.531 0.33 14.76 13,287 29,166 36,957 3,850 3,850 25,316 0.58 269.71 54 810 13.50 3.4 0.624 0.290 0.531 0.33 14.96 13,467 38,783 37,825 3,940 3,940 34,843 0.80 269.97 55 825 13.75 2.3 0.422 0.285 0.359 0.14 6.13 5,514 40,356 37,955 3,954 3,954 36,403 0.84 270.01 56 840 14.00 2.3 0.422 0.281 0.359 0.14 6.32 5,688 42,091 38,098 3,969 3,969 38,123 0.88 270.06 57 855 14.25 2.7 0.496 0.277 0.421 0.22 9.80 8,817 46,940 38,499 4,010 4,010 42,930 0.99 270.18 58 870 14.50 2.6 0.477 0.272 0.406 0.20 9.16 8,248 51,178 38,850 4,047 4,047 47,131 1.08 270.29 59 885 14.75 2.6 0.477 0.268 0.406 0.21 9.35 8,416 55,547 39,211 4,084 4,084 51,463 1.18 270.40 60 900 15.00 2.5 0.459 0.264 0.390 0.19 8.71 7,842 59,305 39,522 4,117 4,117 55,188 1.27 270.49 61 915 15.25 2.4 0.441 0.260 0.375 0.18 8.07 7,266 62,454 39,782 4,144 4,144 58,310 1.34 270.57 62 930 15.50 2.3 0.422 0.256 0.359 0.17 7.43 6,687 64,997 39,992 4,166 4,166 60,831 1.40 270.64 63 945 15.75 1.9 0.349 0.252 0.297 0.10 4.32 3,888 64,719 39,969 4,163 4,163 60,556 1.39 270.63 64 960 16.00 1.9 0.349 0.248 0.297 0.10 4.49 4,043 64,599 39,959 4,162 4,162 60,437 1.39 270.63 65 975 16.25 0.4 0.073 0.245 0.062 0.01 0.49 443 60,880 39,652 4,130 4,130 56,750 1.30 270.53 66 990 16.50 0.4 0.073 0.241 0.062 0.01 0.49 443 57,193 39,347 4,099 4,099 53,095 1.22 270.44 67 1005 16.75 0.3 0.055 0.237 0.047 0.01 0.37 333 53,427 39,036 4,066 4,066 49,361 1.13 270.34 68 1020 17.00 0.3 0.055 0.234 0.047 0.01 0.37 333 49,694 38,727 4,034 4,034 45,660 1.05 270.25 69 1035 17.25 0.5 0.092 0.230 0.078 0.01 0.62 554 46,214 38,439 4,004 4,004 42,210 0.97 270.16 70 1050 17.50 0.5 0.092 0.227 0.078 0.01 0.62 554 42,764 38,154 3,974 3,974 38,790 0.89 270.07 71 1065 17.75 0.5 0.092 0.223 0.078 0.01 0.62 554 39,344 37,871 3,945 3,945 35,399 0.81 269.99 72 1080 18.00 0.4 0.073 0.220 0.062 0.01 0.49 443 35,843 37,581 3,915 3,915 31,928 0.73 269.89 73 1095 18.25 0.4 0.073 0.217 0.062 0.01 0.49 443 32,371 37,257 3,881 3,881 28,491 0.65 269.79 74 1110 18.50 0.4 0.073 0.214 0.062 0.01 0.49 443 28,934 36,935 3,847 3,847 25,087 0.58 269.70 75 1125 18.75 0.3 0.055 0.211 0.047 0.01 0.37 333 25,419 36,607 3,813 3,813 21,606 0.50 269.60 76 1140 19.00 0.2 0.037 0.207 0.031 0.01 0.25 222 21,828 36,271 3,778 3,778 18,050 0.41 269.50 77 1155 19.25 0.3 0.055 0.205 0.047 0.01 0.37 333 18,382 35,949 3,745 3,745 14,637 0.34 269.41 78 1170 19.50 0.4 0.073 0.202 0.062 0.01 0.49 443 15,081 35,641 3,713 3,713 11,368 0.26 269.32 79 1185 19.75 0.3 0.055 0.199 0.047 0.01 0.37 333 11,701 35,325 3,680 3,680 8,021 0.18 269.22 80 1200 20.00 0.2 0.037 0.196 0.031 0.01 0.25 222 8,243 35,001 3,646 3,646 4,597 0.11 269.13 81 1215 20.25 0.3 0.055 0.194 0.047 0.01 0.37 333 4,930 34,692 3,614 3,614 1,316 0.03 269.04 82 1230 20.50 0.3 0.055 0.191 0.047 0.01 0.37 333 1,649 34,385 3,582 1,649 0 0.00 269.00 83 1245 20.75 0.3 0.055 0.189 0.047 0.01 0.37 333 333 34,262 3,569 333 0 0.00 269.00 84 1260 21.00 0.2 0.037 0.186 0.031 0.01 0.25 222 222 34,252 3,568 222 0 0.00 269.00 85 1275 21.25 0.3 0.055 0.184 0.047 0.01 0.37 333 333 34,262 3,569 333 0 0.00 269.00 86 1290 21.50 0.2 0.037 0.182 0.031 0.01 0.25 222 222 34,252 3,568 222 0 0.00 269.00 Plate E-2.2 24-Hour Storm Page 11 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 44.36 VARIABLE LOSS RATE (AVG) IN/HR Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 15 Fm = Minimum value on loss curve (in/hr)0.17 LAG TIME - MINUTES 8.41 C 0.00312 Maxwell Drywells UNIT TIME-PERCENT OF LAG 178%Low Loss Rate (percent)85.00%Number 50 TOTAL ADJUSTED STORM RAIN (in)4.59 Drywell Percolation Rate 0.00 cfs 0.00 cfm Unit Time Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Loss Rate Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD MANUAL 24-HOUR STORM Basin Losses in/hr Total In Basin UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM 87 1305 21.75 0.3 0.055 0.180 0.047 0.01 0.37 333 333 34,262 3,569 333 0 0.00 269.00 88 1320 22.00 0.2 0.037 0.178 0.031 0.01 0.25 222 222 34,252 3,568 222 0 0.00 269.00 89 1335 22.25 0.3 0.055 0.177 0.047 0.01 0.37 333 333 34,262 3,569 333 0 0.00 269.00 90 1350 22.50 0.2 0.037 0.175 0.031 0.01 0.25 222 222 34,252 3,568 222 0 0.00 269.00 91 1365 22.75 0.2 0.037 0.173 0.031 0.01 0.25 222 222 34,252 3,568 222 0 0.00 269.00 92 1380 23.00 0.2 0.037 0.172 0.031 0.01 0.25 222 222 34,252 3,568 222 0 0.00 269.00 93 1395 23.25 0.2 0.037 0.171 0.031 0.01 0.25 222 222 34,252 3,568 222 0 0.00 269.00 94 1410 23.50 0.2 0.037 0.170 0.031 0.01 0.25 222 222 34,252 3,568 222 0 0.00 269.00 95 1425 23.75 0.2 0.037 0.169 0.031 0.01 0.25 222 222 34,252 3,568 222 0 0.00 269.00 96 1440 24.00 0.2 0.037 0.168 0.031 0.01 0.25 222 222 34,252 3,568 222 0 0.00 269.00 EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY TOTAL RAINFALL RAINFALL VOLUME SOIL LOSSES EFFECTIVE RAIN FLOOD VOLUME FLOOD VOLUME REQUIRED STORAGE REQUIRED STORAGE MAX WSEL PEAK FLOW RATE TOTAL BASIN LOSSES AVERAGE PERCOLATION RATE 4.59 in 739,133 cu-ft 558,299 cu-ft 270.64 ft 14.96 cfs 180,833 cu-ft 125.58 cf/min 1.12 in 4.15 acft 180,833 cu-ft 1.40 acft 60,831 cu-ft Plate E-2.2 24-Hour Storm Page 12 of 13 PROECT JOB No. BASIN DESIGNATION: BASIN CHARACTERISTICS CONTOUR ELEVATION INCR TOTAL INCR TOTAL INCR (ft)(ft)(sf)(sf)(cuft)(cuft)(acre-ft) 269 0 0 34,231 0 0 0.00 270 1 1 3,355 37,586 35,895 35,895 0.82 271 1 2 3,241 40,827 39,195 75,091 1.72 272 1 3 2,681 43,508 42,160 117,251 2.69 273 1 4 2,737 46,245 44,870 162,121 3.72 274 1 5 2,793 49,038 47,635 209,755 4.82 275 1 6 2,824 51,862 50,443 260,199 5.97 WHERE: TOTAL Retention Basin G BASIN VOLUME WORKSHEET DEPTH AREA VOLUME Del Webb Explore at Palm Desert 2636 ()()2121213 1 AAAAEEV++−= Basin Volume Worksheet Page 13 of 13 RJB 2 AMC II AREA SOIL TRIBUTARY AREAS ACRES LOW LOSS RI INFILTRATION IMPERVIOUS DESIG GROUP CONDITION NUMBER RATE PERCENT 9 A LANDSCAPING 2.463 D 32 0.74 0.10 2,230 ft 1,115 ft 292.0 ft ELEVATION OF CONCENTRATION POINT 289.0 ft 0.02 100 LOW LOSS RATE (Storm Events > 10 Years)85% POINT RAIN FROM NOAA ATLAS 14 1-HOUR 1.57 in 3-HOUR 2.27 in 6-HOUR 2.98 in 24-HOUR 4.59 in BASIN CHARACTERISTICS:ELEVATION AREA 289.0 ft 348 sf 290.0 ft 19,871 sf 291.0 ft 28,849 sf 292.0 ft 43,242 sf PERCOLATION RATE (in/hr)5.0 in/hr DRYWELL DATA NUMBER USED PERCOLATION RATE LOWEST FLOWLINE ELEVATION LOWEST PAD ELEVATION LENGTH OF WATERCOURSE (L) AREA DESIGNATION ELEVATION OF HEADWATER AVERAGE MANNINGS 'N' VALUE STORM FREQUENCY (YEAR) LENGTH TO POINT OPPOSITE CENTROID (Lca) Low Loss Conditions: X=Existing; D=Developed; BS=Retention DA-H RCFCD SYNTHETIC UNIT HYDROGRAPH - SHORTCUT METHOD DATA INPUT SHEET WORKSHEET PREPARED BY: PROJECT NAME DATE January 10, 2024 Del Webb Explore at Palm Desert PROJECT NUMBER CONCENTRATION POINT DESIGNATION 2636 Retention Basin - H AMC NUMBER Data Input Sheet Page 1 of 13 PROJECT: Job No.: BY:DATE:1/10/24 [1] AMC II [2] FREQUENCY-YEARS 100 FROM NOAA ATLAS 14 [3] STORM DURATION:Point Rain 1-HOUR 1.57 in 3-HOUR 2.27 in 6-HOUR 2.98 in 24-HOUR 4.59 in STORM DURATION 1-HOUR 3-HOUR 6-HOUR 24-HOUR RAINFALL VOLUME (cu-ft)14,037 20,295 26,643 41,038 SOIL LOSSES (cu-ft)6,021 13,685 19,966 35,122 EFFECTIVE RAIN (in)0.90 0.74 0.75 0.66 FLOOD VOLUME (cu-ft)8,016 6,611 6,677 5,916 (acre-ft)0.18 0.15 0.15 0.14 REQUIRED STORAGE (cu-ft)6,201 3,813 3,219 284 (acre-ft)0.14 0.09 0.07 0.01 FACTOR OF SAFETY 10.91 17.74 21.01 238.27 STORAGE PROVIDED (cu-ft) (acre-ft) PEAK FLOW (cfs)n/a 3.88 3.30 0.20 MAXIMUM WSEL (ft)289.81 289.50 289.42 289.04 DEPTH (ft)0.81 0.50 0.42 0.04 DIFFERENCE (ft) DIFFERENCE (ft) ESTIMATED TIME TO DEWATER BASIN Based on Total Flood Volume & Average Percolation Rate (days)0.1 0.2 0.3 1.0 [18] 200% OF LAG-MINUTES RAINFALL DATA 15.8 NOTE: PEAK FLOW FOR THE 1-HOUR STORM IS NOT REPRESENTATIVE. PER RCFCD PEAK DISCHARGES FROM THE 3-HOUR STORM SHOULD NORMALLY COMPARE WELL WITH RATIONAL PEAKS. LOWEST PAD ELEVATION LOWEST FLOWLINE ELEVATION STORM EVENT SUMMARY 67,641 1.55 0.02 [17] 100% OF LAG-MINUTES 7.9 7.9 [14] AVERAGE MANNINGS 'N' [15] LAG TIME-HOURS 0.13 [16] LAG TIME-MINUTES [13] L*LCA/S^0.5 2.67 [11] S-FEET/MILE [6] La-FEET [7] La-MILES [8] ELEVATION OF HEADWATER 0.033 1115.00 [12] S^0.5 0.211 7.1 292 289 3 [3] AREA - ACRES [4] L-FEET [5] L-MILES 2230 0.422 Retention Basin - H DA-H Del Webb Explore at Palm Desert [10] H-FEET [9] ELEVATION OF CONCENTRATION POINT 2.463 PHYSICAL DATA [1] CONCENTRATION POINT HYDROLOGY MANUAL BASIC DATA CALCULATION FORM 2636 RJB RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD [2] AREA DESIGNATION Plate E-2.1 Page 2 of 13 PROJECT: Job No.: BY:DATE:1/10/24 MAX LOW LOW MIN SOIL RI PERVIOUS DECIMAL ADJUSTED AREA AREA AVERAGE LOSS LOSS RATE AVERAGE GROUP NUMBER AREA PERCENT INFILTRATION WEIGHTED ADJUSTED CONDITION PER ADJUSTED INFILTRATION OF AREA RATE AVERAGE INFILTRATION RCFC/2322 INFILTRATION RATE IMPERVIOUS RATE RATE (in/hr)(in/hr)(in/hr) [Plate C-1][Plate E-6.1][Plate E-6.2][Plate E-6.3] A 32 0.74 10%0.67 2.463 1.000 0.6734 DEVELOPED 0.8200 0.8200 SUM 2.463 SUM 0.6734 0.8200 VARIABLE LOSS RATE CURVE (24-HOUR STORM ONLY) Fm=0.3367 NOTE: Low loss rates established per RCFC/2322 (Dated: May-30-95) C=0.00624 For 10 Year Storms or Less Ft=C(24-(T/60))^1.55+Fm =0.00624 0.34 in/hr Undeveloped Condition: Low Loss = 90% CONSTANT LOSS RATE (3 & 6 HOUR STORMS)=0.6734 Developed Condition: Low Loss = 0.9 - (0.8 * %impervious) LOW LOSS RATE =0.8500 Basin Site: Low Loss = 10% Where:For 100 Year Storm - Low Loss should be between 80% & 90% T=Time in minutes. To get an average value for each unit time period, Use T=1/2 the unit time for the first time period,of the Rainfall Rate T=1 1/2 unit time for the second period, etc. (24-(T/60))^1.55 + LAND USE LANDSCAPING AVERAGE ADJUSTED LOSS RATE RCFC & WCD HYDROLOGY MANUAL SYNTHETIC UNIT HYDROGRAPH METHOD BASIC DATA CALCULATION FORM Del Webb Explore at Palm Desert RJB 2636 AMC II Plate E-2.1 Page 3 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/10/24 DRAINAGE AREA-ACRES 2.46 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 7.92 Maxwell Drywells UNIT TIME-PERCENT OF LAG 63.1 Number 0 TOTAL ADJUSTED STORM RAIN-INCHES 1.57 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE-in/hr 0.67 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 5 0.08 3.6 0.68 0.67 0.58 0.00 0.01 4 4 357 12 4 0 0.00 289.00 2 10 0.17 4.2 0.79 0.67 0.67 0.12 0.29 88 88 573 20 20 68 0.00 289.01 3 15 0.25 4.4 0.83 0.67 0.70 0.16 0.39 116 184 819 28 28 155 0.00 289.02 4 20 0.33 4.6 0.87 0.67 0.74 0.19 0.48 144 299 1,115 39 39 261 0.01 289.03 5 25 0.42 5.0 0.94 0.67 0.80 0.27 0.67 200 461 1,529 53 53 408 0.01 289.05 6 30 0.50 5.6 1.06 0.67 0.90 0.38 0.95 284 692 2,122 74 74 618 0.01 289.08 7 35 0.58 6.4 1.21 0.67 1.02 0.53 1.32 397 1,015 2,950 102 102 913 0.02 289.12 8 40 0.67 8.1 1.53 0.67 1.30 0.85 2.12 635 1,548 4,316 150 150 1,398 0.03 289.18 9 45 0.75 13.1 2.47 0.67 2.10 1.79 4.46 1,337 2,735 7,359 256 256 2,480 0.06 289.33 10 50 0.83 34.5 6.50 0.67 5.52 5.83 14.47 4,341 6,821 17,832 619 619 6,201 0.14 289.81 11 55 0.92 6.7 1.26 0.67 1.07 0.59 1.46 439 6,640 17,369 603 603 6,037 0.14 289.79 12 60 1.00 3.8 0.72 0.67 0.61 0.04 0.11 32 6,069 15,904 552 552 5,517 0.13 289.72 TOTAL RAINFALL 1.57 in RAINFALL VOLUME 14,037 cu-ft SOIL LOSSES 6,021 cu-ft EFFECTIVE RAIN 0.90 in FLOOD VOLUME 0.18 acft FLOOD VOLUME 8,016 cu-ft REQUIRED STORAGE 0.14 REQUIRED STORAGE 6,201 cu-ft MAX WSEL 289.81 ft PEAK FLOW RATE 14.47 cfs TOTAL BASIN LOSSES 2,500 cu-ft AVERAGE PERCOLATION RATE 41.66 cf/min EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Total In Basin in/hr Time Loss Rate Basin Losses Del Webb Explore at Palm DesertRCFC & WCD HYDROLOGY MANUAL SYNTHETIC UNIT HYDROGRAPH METHOD SHORTCUT METHOD 1-HOUR STORM Plate E-2.2 1-Hour Storm Page 4 of 13 PROJECT: Job No.:2636 BY:RJB DATE DRAINAGE AREA-ACRES 2.46 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 7.92 Maxwell Drywells UNIT TIME-PERCENT OF LAG 63.1 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.27 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.67 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 5 0.08 1.3 0.35 0.67 0.30 0.05 0.13 40 40 449 16 16 24 0.00 289.00 2 10 0.17 1.3 0.35 0.67 0.30 0.05 0.13 40 64 511 18 18 46 0.00 289.01 3 15 0.25 1.1 0.30 0.67 0.25 0.04 0.11 33 79 551 19 19 60 0.00 289.01 4 20 0.33 1.5 0.41 0.67 0.35 0.06 0.15 46 106 619 22 22 84 0.00 289.01 5 25 0.42 1.5 0.41 0.67 0.35 0.06 0.15 46 130 681 24 24 106 0.00 289.01 6 30 0.50 1.8 0.49 0.67 0.42 0.07 0.18 55 161 761 26 26 135 0.00 289.02 7 35 0.58 1.5 0.41 0.67 0.35 0.06 0.15 46 180 810 28 28 152 0.00 289.02 8 40 0.67 1.8 0.49 0.67 0.42 0.07 0.18 55 207 879 31 31 177 0.00 289.02 9 45 0.75 1.8 0.49 0.67 0.42 0.07 0.18 55 231 941 33 33 199 0.00 289.03 10 50 0.83 1.5 0.41 0.67 0.35 0.06 0.15 46 244 974 34 34 210 0.00 289.03 11 55 0.92 1.6 0.44 0.67 0.37 0.07 0.16 49 259 1,012 35 35 224 0.01 289.03 12 60 1.00 1.8 0.49 0.67 0.42 0.07 0.18 55 279 1,063 37 37 242 0.01 289.03 13 65 1.08 2.2 0.60 0.67 0.51 0.09 0.22 67 309 1,140 40 40 269 0.01 289.04 14 70 1.17 2.2 0.60 0.67 0.51 0.09 0.22 67 336 1,210 42 42 294 0.01 289.04 15 75 1.25 2.2 0.60 0.67 0.51 0.09 0.22 67 361 1,274 44 44 317 0.01 289.04 16 80 1.33 2.0 0.54 0.67 0.46 0.08 0.20 61 378 1,317 46 46 332 0.01 289.04 17 85 1.42 2.6 0.71 0.67 0.60 0.03 0.09 26 358 1,266 44 44 314 0.01 289.04 18 90 1.50 2.7 0.74 0.67 0.63 0.06 0.15 46 360 1,272 44 44 316 0.01 289.04 19 95 1.58 2.4 0.65 0.67 0.56 0.10 0.24 73 389 1,346 47 47 343 0.01 289.04 20 100 1.67 2.7 0.74 0.67 0.63 0.06 0.15 46 389 1,345 47 47 342 0.01 289.04 21 105 1.75 3.3 0.90 0.67 0.76 0.23 0.56 168 510 1,656 57 57 453 0.01 289.06 22 110 1.83 3.1 0.84 0.67 0.72 0.17 0.42 127 580 1,835 64 64 516 0.01 289.07 23 115 1.92 2.9 0.79 0.67 0.67 0.12 0.29 87 603 1,894 66 66 537 0.01 289.07 24 120 2.00 3.0 0.82 0.67 0.69 0.14 0.36 107 645 2,000 69 69 575 0.01 289.08 25 125 2.08 3.1 0.84 0.67 0.72 0.17 0.42 127 703 2,149 75 75 628 0.01 289.08 RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 3-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Loss Rate Basin Losses Plate E-2.2 3-Hour Storm Page 5 of 13 PROJECT: Job No.:2636 BY:RJB DATE DRAINAGE AREA-ACRES 2.46 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 7.92 Maxwell Drywells UNIT TIME-PERCENT OF LAG 63.1 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.27 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.67 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 3-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Loss Rate Basin Losses 26 130 2.17 4.2 1.14 0.67 0.97 0.47 1.17 351 979 2,857 99 99 879 0.02 289.12 27 135 2.25 5.0 1.36 0.67 1.16 0.69 1.71 513 1,393 3,918 136 136 1,257 0.03 289.16 28 140 2.33 3.5 0.95 0.67 0.81 0.28 0.70 209 1,465 4,104 142 142 1,323 0.03 289.17 29 145 2.42 6.8 1.85 0.67 1.57 1.18 2.93 878 2,201 5,990 208 208 1,993 0.05 289.26 30 150 2.50 7.3 1.99 0.67 1.69 1.32 3.27 980 2,973 7,968 277 277 2,696 0.06 289.35 31 155 2.58 8.2 2.23 0.67 1.90 1.56 3.88 1,163 3,859 10,239 356 356 3,503 0.08 289.46 32 160 2.67 5.9 1.61 0.67 1.37 0.93 2.32 696 4,199 11,111 386 386 3,813 0.09 289.50 33 165 2.75 2.0 0.54 0.67 0.46 0.08 0.20 61 3,874 10,278 357 357 3,517 0.08 289.46 34 170 2.83 1.8 0.49 0.67 0.42 0.07 0.18 55 3,572 9,504 330 330 3,242 0.07 289.43 35 175 2.92 1.8 0.49 0.67 0.42 0.07 0.18 55 3,297 8,798 306 306 2,991 0.07 289.39 36 180 3.00 0.6 0.16 0.67 0.14 0.02 0.06 18 3,009 8,062 280 280 2,729 0.06 289.36 TOTAL RAIN RAINFALL VOLUME SOIL LOSSES EFFECTIVE RAIN FLOOD VOLUME FLOOD VOLUME REQUIRED STORAGE REQUIRED STORAGE MAX WSEL PEAK FLOW RATE TOTAL BASIN LOSSES AVERAGE PERCOLATION RATE EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY 3,881 cu-ft 21.56 cf/min 0.74 in 0.15 acft 6,611 cu-ft 0.09 acft 3,813 cu-ft 13,685 cu-ft 2.27 in 20,295 cu-ft 289.50 ft 3.88 cfs Plate E-2.2 3-Hour Storm Page 6 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/10/24 DRAINAGE AREA-ACRES 2.46 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 7.92 Maxwell Drywells UNIT TIME-PERCENT OF LAG 63.1 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.98 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.67 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 5 0.08 0.5 0.18 0.67 0.15 0.03 0.07 20 20 399 14 14 6 0.00 289.00 2 10 0.17 0.6 0.21 0.67 0.18 0.03 0.08 24 30 425 15 15 15 0.00 289.00 3 15 0.25 0.6 0.21 0.67 0.18 0.03 0.08 24 39 449 16 16 24 0.00 289.00 4 20 0.33 0.6 0.21 0.67 0.18 0.03 0.08 24 48 470 16 16 31 0.00 289.00 5 25 0.42 0.6 0.21 0.67 0.18 0.03 0.08 24 55 490 17 17 38 0.00 289.01 6 30 0.50 0.7 0.25 0.67 0.21 0.04 0.09 28 66 518 18 18 48 0.00 289.01 7 35 0.58 0.7 0.25 0.67 0.21 0.04 0.09 28 76 544 19 19 57 0.00 289.01 8 40 0.67 0.7 0.25 0.67 0.21 0.04 0.09 28 85 567 20 20 66 0.00 289.01 9 45 0.75 0.7 0.25 0.67 0.21 0.04 0.09 28 94 588 20 20 73 0.00 289.01 10 50 0.83 0.7 0.25 0.67 0.21 0.04 0.09 28 101 608 21 21 80 0.00 289.01 11 55 0.92 0.7 0.25 0.67 0.21 0.04 0.09 28 108 625 22 22 86 0.00 289.01 12 60 1.00 0.8 0.29 0.67 0.24 0.04 0.11 32 118 652 23 23 96 0.00 289.01 13 65 1.08 0.8 0.29 0.67 0.24 0.04 0.11 32 128 675 23 23 104 0.00 289.01 14 70 1.17 0.8 0.29 0.67 0.24 0.04 0.11 32 136 697 24 24 112 0.00 289.01 15 75 1.25 0.8 0.29 0.67 0.24 0.04 0.11 32 144 717 25 25 119 0.00 289.02 16 80 1.33 0.8 0.29 0.67 0.24 0.04 0.11 32 151 735 26 26 126 0.00 289.02 17 85 1.42 0.8 0.29 0.67 0.24 0.04 0.11 32 158 752 26 26 131 0.00 289.02 18 90 1.50 0.8 0.29 0.67 0.24 0.04 0.11 32 163 767 27 27 137 0.00 289.02 19 95 1.58 0.8 0.29 0.67 0.24 0.04 0.11 32 169 781 27 27 142 0.00 289.02 20 100 1.67 0.8 0.29 0.67 0.24 0.04 0.11 32 174 793 28 28 146 0.00 289.02 21 105 1.75 0.8 0.29 0.67 0.24 0.04 0.11 32 178 804 28 28 150 0.00 289.02 22 110 1.83 0.8 0.29 0.67 0.24 0.04 0.11 32 182 815 28 28 154 0.00 289.02 23 115 1.92 0.8 0.29 0.67 0.24 0.04 0.11 32 186 824 29 29 157 0.00 289.02 24 120 2.00 0.9 0.32 0.67 0.27 0.05 0.12 36 193 843 29 29 164 0.00 289.02 Loss Rate RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 6-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Basin Losses Plate E-2.2 6-Hour Storm Page 7 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/10/24 DRAINAGE AREA-ACRES 2.46 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 7.92 Maxwell Drywells UNIT TIME-PERCENT OF LAG 63.1 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.98 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.67 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft Loss Rate RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 6-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Basin Losses 25 125 2.08 0.8 0.29 0.67 0.24 0.04 0.11 32 196 850 30 30 166 0.00 289.02 26 130 2.17 0.9 0.32 0.67 0.27 0.05 0.12 36 202 867 30 30 172 0.00 289.02 27 135 2.25 0.9 0.32 0.67 0.27 0.05 0.12 36 208 882 31 31 178 0.00 289.02 28 140 2.33 0.9 0.32 0.67 0.27 0.05 0.12 36 214 895 31 31 182 0.00 289.02 29 145 2.42 0.9 0.32 0.67 0.27 0.05 0.12 36 218 908 32 32 187 0.00 289.02 30 150 2.50 0.9 0.32 0.67 0.27 0.05 0.12 36 223 919 32 32 191 0.00 289.03 31 155 2.58 0.9 0.32 0.67 0.27 0.05 0.12 36 227 930 32 32 195 0.00 289.03 32 160 2.67 0.9 0.32 0.67 0.27 0.05 0.12 36 231 939 33 33 198 0.00 289.03 33 165 2.75 1.0 0.36 0.67 0.30 0.05 0.13 40 238 958 33 33 205 0.00 289.03 34 170 2.83 1.0 0.36 0.67 0.30 0.05 0.13 40 245 975 34 34 211 0.00 289.03 35 175 2.92 1.0 0.36 0.67 0.30 0.05 0.13 40 251 991 34 34 216 0.00 289.03 36 180 3.00 1.0 0.36 0.67 0.30 0.05 0.13 40 256 1,005 35 35 221 0.01 289.03 37 185 3.08 1.0 0.36 0.67 0.30 0.05 0.13 40 261 1,018 35 35 226 0.01 289.03 38 190 3.17 1.1 0.39 0.67 0.33 0.06 0.15 44 270 1,040 36 36 234 0.01 289.03 39 195 3.25 1.1 0.39 0.67 0.33 0.06 0.15 44 278 1,060 37 37 241 0.01 289.03 40 200 3.33 1.1 0.39 0.67 0.33 0.06 0.15 44 285 1,079 37 37 248 0.01 289.03 41 205 3.42 1.2 0.43 0.67 0.36 0.06 0.16 48 296 1,105 38 38 257 0.01 289.03 42 210 3.50 1.3 0.46 0.67 0.40 0.07 0.17 52 309 1,140 40 40 269 0.01 289.04 43 215 3.58 1.4 0.50 0.67 0.43 0.08 0.19 56 325 1,182 41 41 284 0.01 289.04 44 220 3.67 1.4 0.50 0.67 0.43 0.08 0.19 56 340 1,220 42 42 298 0.01 289.04 45 225 3.75 1.5 0.54 0.67 0.46 0.08 0.20 60 358 1,265 44 44 314 0.01 289.04 46 230 3.83 1.5 0.54 0.67 0.46 0.08 0.20 60 374 1,306 45 45 329 0.01 289.04 47 235 3.92 1.6 0.57 0.67 0.49 0.09 0.21 64 392 1,354 47 47 345 0.01 289.05 48 240 4.00 1.6 0.57 0.67 0.49 0.09 0.21 64 409 1,397 49 49 361 0.01 289.05 49 245 4.08 1.7 0.61 0.67 0.52 0.09 0.23 68 429 1,447 50 50 379 0.01 289.05 50 250 4.17 1.8 0.64 0.67 0.55 0.10 0.24 72 451 1,503 52 52 398 0.01 289.05 Plate E-2.2 6-Hour Storm Page 8 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/10/24 DRAINAGE AREA-ACRES 2.46 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 7.92 Maxwell Drywells UNIT TIME-PERCENT OF LAG 63.1 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.98 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.67 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft Loss Rate RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 6-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Basin Losses 51 255 4.25 1.9 0.68 0.67 0.58 0.01 0.02 5 403 1,381 48 48 355 0.01 289.05 52 260 4.33 2.0 0.72 0.67 0.61 0.04 0.10 31 386 1,338 46 46 340 0.01 289.04 53 265 4.42 2.1 0.75 0.67 0.64 0.08 0.19 58 397 1,367 47 47 350 0.01 289.05 54 270 4.50 2.1 0.75 0.67 0.64 0.08 0.19 58 408 1,393 48 48 359 0.01 289.05 55 275 4.58 2.2 0.79 0.67 0.67 0.11 0.28 84 444 1,486 52 52 392 0.01 289.05 56 280 4.67 2.3 0.82 0.67 0.70 0.15 0.37 111 503 1,638 57 57 446 0.01 289.06 57 285 4.75 2.4 0.86 0.67 0.73 0.18 0.46 138 584 1,845 64 64 520 0.01 289.07 58 290 4.83 2.4 0.86 0.67 0.73 0.18 0.46 138 658 2,034 71 71 587 0.01 289.08 59 295 4.92 2.5 0.89 0.67 0.76 0.22 0.55 164 751 2,274 79 79 673 0.02 289.09 60 300 5.00 2.6 0.93 0.67 0.79 0.26 0.64 191 864 2,562 89 89 775 0.02 289.10 61 305 5.08 3.1 1.11 0.67 0.94 0.44 1.08 324 1,099 3,165 110 110 989 0.02 289.13 62 310 5.17 3.6 1.29 0.67 1.09 0.61 1.52 457 1,446 4,056 141 141 1,306 0.03 289.17 63 315 5.25 3.9 1.39 0.67 1.19 0.72 1.79 537 1,843 5,072 176 176 1,667 0.04 289.22 64 320 5.33 4.2 1.50 0.67 1.28 0.83 2.06 617 2,284 6,203 215 215 2,069 0.05 289.27 65 325 5.42 4.7 1.68 0.67 1.43 1.01 2.50 751 2,819 7,575 263 263 2,556 0.06 289.34 66 330 5.50 5.6 2.00 0.67 1.70 1.33 3.30 990 3,547 9,439 328 328 3,219 0.07 289.42 67 335 5.58 1.9 0.68 0.67 0.58 0.01 0.02 5 3,223 8,610 299 299 2,924 0.07 289.38 68 340 5.67 0.9 0.32 0.67 0.27 0.05 0.12 36 2,960 7,936 276 276 2,685 0.06 289.35 69 345 5.75 0.6 0.21 0.67 0.18 0.03 0.08 24 2,709 7,291 253 253 2,456 0.06 289.32 70 350 5.83 0.5 0.18 0.67 0.15 0.03 0.07 20 2,476 6,694 232 232 2,243 0.05 289.29 71 355 5.92 0.3 0.11 0.67 0.09 0.02 0.04 12 2,255 6,129 213 213 2,042 0.05 289.27 72 360 6.00 0.2 0.07 0.67 0.06 0.01 0.03 8 2,050 5,604 195 195 1,856 0.04 289.24 TOTAL RAINFALL RAINFALL VOLUME SOIL LOSSES EFFECTIVE RAIN FLOOD VOLUME FLOOD VOLUME REQUIRED STORAGE REQUIRED STORAGE MAX WSEL PEAK FLOW RATE TOTAL BASIN LOSSES AVERAGE PERCOLATION RATE EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY 13.39 cf/min 4,822 cu-ft 0.75 in 0.15 acft 6,677 cu-ft 0.07 acft 3,219 cu-ft 26,643 cu-ft 2.98 in 19,966 cu-ft 289.42 ft 3.30 cfs Plate E-2.2 6-Hour Storm Page 9 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/10/24 DRAINAGE AREA-ACRES 2.46 VARIABLE LOSS RATE (AVG) IN/HR Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 15 Fm = Minimum value on loss curve (in/hr)0.34 LAG TIME - MINUTES 7.92 C 0.00624 Maxwell Drywells UNIT TIME-PERCENT OF LAG 189%Low Loss Rate (percent)85.00%Number 0 TOTAL ADJUSTED STORM RAIN (in)4.59 Drywell Percolation Rate 0.00 cfs 0.00 cfm Unit Time Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 15 0.25 0.2 0.037 1.189 0.031 0.01 0.01 12 12 380 40 12 0 0.00 289.00 2 30 0.50 0.3 0.055 1.175 0.047 0.01 0.02 18 18 395 41 18 0 0.00 289.00 3 45 0.75 0.3 0.055 1.162 0.047 0.01 0.02 18 18 395 41 18 0 0.00 289.00 4 60 1.00 0.4 0.073 1.148 0.062 0.01 0.03 25 25 411 43 25 0 0.00 289.00 5 75 1.25 0.3 0.055 1.134 0.047 0.01 0.02 18 18 395 41 18 0 0.00 289.00 6 90 1.50 0.3 0.055 1.121 0.047 0.01 0.02 18 18 395 41 18 0 0.00 289.00 7 105 1.75 0.3 0.055 1.108 0.047 0.01 0.02 18 18 395 41 18 0 0.00 289.00 8 120 2.00 0.4 0.073 1.094 0.062 0.01 0.03 25 25 411 43 25 0 0.00 289.00 9 135 2.25 0.4 0.073 1.081 0.062 0.01 0.03 25 25 411 43 25 0 0.00 289.00 10 150 2.50 0.4 0.073 1.068 0.062 0.01 0.03 25 25 411 43 25 0 0.00 289.00 11 165 2.75 0.5 0.092 1.055 0.078 0.01 0.03 31 31 427 44 31 0 0.00 289.00 12 180 3.00 0.5 0.092 1.042 0.078 0.01 0.03 31 31 427 44 31 0 0.00 289.00 13 195 3.25 0.5 0.092 1.029 0.078 0.01 0.03 31 31 427 44 31 0 0.00 289.00 14 210 3.50 0.5 0.092 1.016 0.078 0.01 0.03 31 31 427 44 31 0 0.00 289.00 15 225 3.75 0.5 0.092 1.003 0.078 0.01 0.03 31 31 427 44 31 0 0.00 289.00 16 240 4.00 0.6 0.110 0.991 0.094 0.02 0.04 37 37 443 46 37 0 0.00 289.00 17 255 4.25 0.6 0.110 0.978 0.094 0.02 0.04 37 37 443 46 37 0 0.00 289.00 18 270 4.50 0.7 0.129 0.966 0.109 0.02 0.05 43 43 458 48 43 0 0.00 289.00 19 285 4.75 0.7 0.129 0.953 0.109 0.02 0.05 43 43 458 48 43 0 0.00 289.00 20 300 5.00 0.8 0.147 0.941 0.125 0.02 0.05 49 49 474 49 49 0 0.00 289.00 21 315 5.25 0.6 0.110 0.929 0.094 0.02 0.04 37 37 443 46 37 0 0.00 289.00 22 330 5.50 0.7 0.129 0.917 0.109 0.02 0.05 43 43 458 48 43 0 0.00 289.00 23 345 5.75 0.8 0.147 0.905 0.125 0.02 0.05 49 49 474 49 49 0 0.00 289.00 24 360 6.00 0.8 0.147 0.893 0.125 0.02 0.05 49 49 474 49 49 0 0.00 289.00 25 375 6.25 0.9 0.165 0.881 0.140 0.02 0.06 55 55 490 51 51 4 0.00 289.00 26 390 6.50 0.9 0.165 0.869 0.140 0.02 0.06 55 60 501 52 52 8 0.00 289.00 27 405 6.75 1.0 0.184 0.858 0.156 0.03 0.07 62 69 525 55 55 14 0.00 289.00 28 420 7.00 1.0 0.184 0.846 0.156 0.03 0.07 62 76 543 57 57 19 0.00 289.00 29 435 7.25 1.0 0.184 0.835 0.156 0.03 0.07 62 81 556 58 58 23 0.00 289.00 30 450 7.50 1.1 0.202 0.823 0.172 0.03 0.08 68 91 581 61 61 30 0.00 289.00 31 465 7.75 1.2 0.220 0.812 0.187 0.03 0.08 74 104 615 64 64 40 0.00 289.01 32 480 8.00 1.3 0.239 0.801 0.203 0.04 0.09 80 120 656 68 68 52 0.00 289.01 33 495 8.25 1.5 0.275 0.790 0.234 0.04 0.10 92 144 718 75 75 69 0.00 289.01 34 510 8.50 1.5 0.275 0.779 0.234 0.04 0.10 92 162 763 79 79 82 0.00 289.01 35 525 8.75 1.6 0.294 0.768 0.250 0.04 0.11 98 181 811 85 85 96 0.00 289.01 36 540 9.00 1.7 0.312 0.757 0.265 0.05 0.12 105 201 863 90 90 111 0.00 289.01 37 555 9.25 1.9 0.349 0.746 0.297 0.05 0.13 117 228 932 97 97 131 0.00 289.02 38 570 9.50 2.0 0.367 0.735 0.312 0.06 0.14 123 254 999 104 104 150 0.00 289.02 39 585 9.75 2.1 0.386 0.725 0.328 0.06 0.14 129 279 1,064 111 111 168 0.00 289.02 40 600 10.00 2.2 0.404 0.715 0.343 0.06 0.15 135 304 1,127 117 117 186 0.00 289.02 41 615 10.25 1.5 0.275 0.704 0.234 0.04 0.10 92 279 1,063 111 111 168 0.00 289.02 42 630 10.50 1.5 0.275 0.694 0.234 0.04 0.10 92 260 1,016 106 106 155 0.00 289.02 43 645 10.75 2.0 0.367 0.684 0.312 0.06 0.14 123 278 1,060 110 110 167 0.00 289.02 in/hr Total In Basin UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Loss Rate Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD MANUAL 24-HOUR STORM Basin Losses Plate E-2.2 24-Hour Storm Page 10 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/10/24 DRAINAGE AREA-ACRES 2.46 VARIABLE LOSS RATE (AVG) IN/HR Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 15 Fm = Minimum value on loss curve (in/hr)0.34 LAG TIME - MINUTES 7.92 C 0.00624 Maxwell Drywells UNIT TIME-PERCENT OF LAG 189%Low Loss Rate (percent)85.00%Number 0 TOTAL ADJUSTED STORM RAIN (in)4.59 Drywell Percolation Rate 0.00 cfs 0.00 cfm Unit Time Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft in/hr Total In Basin UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Loss Rate Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD MANUAL 24-HOUR STORM Basin Losses 44 660 11.00 2.0 0.367 0.674 0.312 0.06 0.14 123 290 1,093 114 114 177 0.00 289.02 45 675 11.25 1.9 0.349 0.664 0.297 0.05 0.13 117 294 1,101 115 115 179 0.00 289.02 46 690 11.50 1.9 0.349 0.654 0.297 0.05 0.13 117 296 1,107 115 115 181 0.00 289.02 47 705 11.75 1.7 0.312 0.645 0.265 0.05 0.12 105 285 1,079 112 112 173 0.00 289.02 48 720 12.00 1.8 0.330 0.635 0.281 0.05 0.12 111 284 1,075 112 112 172 0.00 289.02 49 735 12.25 2.5 0.459 0.625 0.390 0.07 0.17 154 326 1,183 123 123 202 0.00 289.03 50 750 12.50 2.6 0.477 0.616 0.406 0.07 0.18 160 362 1,277 133 133 229 0.01 289.03 51 765 12.75 2.8 0.514 0.607 0.437 0.08 0.19 172 402 1,378 144 144 258 0.01 289.03 52 780 13.00 2.9 0.532 0.598 0.453 0.08 0.20 179 437 1,468 153 153 284 0.01 289.04 53 795 13.25 3.4 0.624 0.589 0.531 0.04 0.09 80 363 1,280 133 133 230 0.01 289.03 54 810 13.50 3.4 0.624 0.580 0.531 0.04 0.11 99 330 1,193 124 124 205 0.00 289.03 55 825 13.75 2.3 0.422 0.571 0.359 0.06 0.16 142 347 1,237 129 129 218 0.01 289.03 56 840 14.00 2.3 0.422 0.562 0.359 0.06 0.16 142 360 1,270 132 132 227 0.01 289.03 57 855 14.25 2.7 0.496 0.554 0.421 0.07 0.18 166 394 1,357 141 141 252 0.01 289.03 58 870 14.50 2.6 0.477 0.545 0.406 0.07 0.18 160 412 1,405 146 146 266 0.01 289.03 59 885 14.75 2.6 0.477 0.537 0.406 0.07 0.18 160 426 1,440 150 150 276 0.01 289.04 60 900 15.00 2.5 0.459 0.529 0.390 0.07 0.17 154 430 1,450 151 151 279 0.01 289.04 61 915 15.25 2.4 0.441 0.521 0.375 0.07 0.16 148 427 1,441 150 150 276 0.01 289.04 62 930 15.50 2.3 0.422 0.513 0.359 0.06 0.16 142 418 1,420 148 148 270 0.01 289.04 63 945 15.75 1.9 0.349 0.505 0.297 0.05 0.13 117 387 1,340 140 140 247 0.01 289.03 64 960 16.00 1.9 0.349 0.497 0.297 0.05 0.13 117 364 1,282 134 134 231 0.01 289.03 65 975 16.25 0.4 0.073 0.489 0.062 0.01 0.03 25 256 1,003 104 104 151 0.00 289.02 66 990 16.50 0.4 0.073 0.482 0.062 0.01 0.03 25 176 798 83 83 93 0.00 289.01 67 1005 16.75 0.3 0.055 0.475 0.047 0.01 0.02 18 111 632 66 66 45 0.00 289.01 68 1020 17.00 0.3 0.055 0.468 0.047 0.01 0.02 18 64 511 53 53 10 0.00 289.00 69 1035 17.25 0.5 0.092 0.460 0.078 0.01 0.03 31 41 453 47 41 0 0.00 289.00 70 1050 17.50 0.5 0.092 0.454 0.078 0.01 0.03 31 31 427 44 31 0 0.00 289.00 71 1065 17.75 0.5 0.092 0.447 0.078 0.01 0.03 31 31 427 44 31 0 0.00 289.00 72 1080 18.00 0.4 0.073 0.440 0.062 0.01 0.03 25 25 411 43 25 0 0.00 289.00 73 1095 18.25 0.4 0.073 0.434 0.062 0.01 0.03 25 25 411 43 25 0 0.00 289.00 74 1110 18.50 0.4 0.073 0.427 0.062 0.01 0.03 25 25 411 43 25 0 0.00 289.00 75 1125 18.75 0.3 0.055 0.421 0.047 0.01 0.02 18 18 395 41 18 0 0.00 289.00 76 1140 19.00 0.2 0.037 0.415 0.031 0.01 0.01 12 12 380 40 12 0 0.00 289.00 77 1155 19.25 0.3 0.055 0.409 0.047 0.01 0.02 18 18 395 41 18 0 0.00 289.00 78 1170 19.50 0.4 0.073 0.404 0.062 0.01 0.03 25 25 411 43 25 0 0.00 289.00 79 1185 19.75 0.3 0.055 0.398 0.047 0.01 0.02 18 18 395 41 18 0 0.00 289.00 80 1200 20.00 0.2 0.037 0.393 0.031 0.01 0.01 12 12 380 40 12 0 0.00 289.00 81 1215 20.25 0.3 0.055 0.388 0.047 0.01 0.02 18 18 395 41 18 0 0.00 289.00 82 1230 20.50 0.3 0.055 0.383 0.047 0.01 0.02 18 18 395 41 18 0 0.00 289.00 83 1245 20.75 0.3 0.055 0.378 0.047 0.01 0.02 18 18 395 41 18 0 0.00 289.00 84 1260 21.00 0.2 0.037 0.373 0.031 0.01 0.01 12 12 380 40 12 0 0.00 289.00 85 1275 21.25 0.3 0.055 0.369 0.047 0.01 0.02 18 18 395 41 18 0 0.00 289.00 86 1290 21.50 0.2 0.037 0.365 0.031 0.01 0.01 12 12 380 40 12 0 0.00 289.00 Plate E-2.2 24-Hour Storm Page 11 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/10/24 DRAINAGE AREA-ACRES 2.46 VARIABLE LOSS RATE (AVG) IN/HR Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 15 Fm = Minimum value on loss curve (in/hr)0.34 LAG TIME - MINUTES 7.92 C 0.00624 Maxwell Drywells UNIT TIME-PERCENT OF LAG 189%Low Loss Rate (percent)85.00%Number 0 TOTAL ADJUSTED STORM RAIN (in)4.59 Drywell Percolation Rate 0.00 cfs 0.00 cfm Unit Time Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft in/hr Total In Basin UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Loss Rate Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD MANUAL 24-HOUR STORM Basin Losses 87 1305 21.75 0.3 0.055 0.361 0.047 0.01 0.02 18 18 395 41 18 0 0.00 289.00 88 1320 22.00 0.2 0.037 0.357 0.031 0.01 0.01 12 12 380 40 12 0 0.00 289.00 89 1335 22.25 0.3 0.055 0.353 0.047 0.01 0.02 18 18 395 41 18 0 0.00 289.00 90 1350 22.50 0.2 0.037 0.350 0.031 0.01 0.01 12 12 380 40 12 0 0.00 289.00 91 1365 22.75 0.2 0.037 0.347 0.031 0.01 0.01 12 12 380 40 12 0 0.00 289.00 92 1380 23.00 0.2 0.037 0.344 0.031 0.01 0.01 12 12 380 40 12 0 0.00 289.00 93 1395 23.25 0.2 0.037 0.342 0.031 0.01 0.01 12 12 380 40 12 0 0.00 289.00 94 1410 23.50 0.2 0.037 0.340 0.031 0.01 0.01 12 12 380 40 12 0 0.00 289.00 95 1425 23.75 0.2 0.037 0.338 0.031 0.01 0.01 12 12 380 40 12 0 0.00 289.00 96 1440 24.00 0.2 0.037 0.337 0.031 0.01 0.01 12 12 380 40 12 0 0.00 289.00 EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY TOTAL RAINFALL RAINFALL VOLUME SOIL LOSSES EFFECTIVE RAIN FLOOD VOLUME FLOOD VOLUME REQUIRED STORAGE REQUIRED STORAGE MAX WSEL PEAK FLOW RATE TOTAL BASIN LOSSES AVERAGE PERCOLATION RATE 5,916 cu-ft 4.11 cf/min 0.66 in 0.14 acft 5,916 cu-ft 0.01 acft 284 cu-ft 4.59 in 41,038 cu-ft 35,122 cu-ft 289.04 ft 0.20 cfs Plate E-2.2 24-Hour Storm Page 12 of 13 PROECT JOB No. BASIN DESIGNATION: BASIN CHARACTERISTICS CONTOUR ELEVATION INCR TOTAL INCR TOTAL INCR (ft)(ft)(sf)(sf)(cuft)(cuft)(acre-ft) 289 0 0 348 0 0 0.00 290 1 1 19,523 19,871 7,616 7,616 0.17 291 1 2 8,978 28,849 24,221 31,837 0.73 292 1 3 14,393 43,242 35,804 67,641 1.55 WHERE: TOTAL Retention Basin - H BASIN VOLUME WORKSHEET DEPTH AREA VOLUME Del Webb Explore at Palm Desert 2636 ()()2121213 1 AAAAEEV++−= Basin Volume Worksheet Page 13 of 13 RJB 2 AMC II AREA SOIL TRIBUTARY AREAS ACRES LOW LOSS RI INFILTRATION IMPERVIOUS DESIG GROUP CONDITION NUMBER RATE PERCENT 9 A LANDSCAPING 1.331 D 32 0.74 0.10 715 ft 3,578 ft 296.3 ft ELEVATION OF CONCENTRATION POINT 291.0 ft 0.02 100 LOW LOSS RATE (Storm Events > 10 Years)85% POINT RAIN FROM NOAA ATLAS 14 1-HOUR 1.57 in 3-HOUR 2.27 in 6-HOUR 2.98 in 24-HOUR 4.59 in BASIN CHARACTERISTICS:ELEVATION AREA 285.7 ft 3,785 sf 286.0 ft 4,241 sf 287.0 ft 5,743 sf 288.0 ft 7,481 sf 289.0 ft 9,538 sf 290.0 ft 11,971 sf 291.0 ft 14,944 sf PERCOLATION RATE (in/hr)5.0 in/hr DRYWELL DATA NUMBER USED PERCOLATION RATE LOWEST FLOWLINE ELEVATION LOWEST PAD ELEVATION PROJECT NUMBER CONCENTRATION POINT DESIGNATION 2636 Retention Basin - I AMC NUMBER RCFCD SYNTHETIC UNIT HYDROGRAPH - SHORTCUT METHOD DATA INPUT SHEET WORKSHEET PREPARED BY: PROJECT NAME DATE January 9, 2024 Del Webb Explore at Palm Desert LENGTH OF WATERCOURSE (L) AREA DESIGNATION ELEVATION OF HEADWATER AVERAGE MANNINGS 'N' VALUE STORM FREQUENCY (YEAR) LENGTH TO POINT OPPOSITE CENTROID (Lca) Low Loss Conditions: X=Existing; D=Developed; BS=Retention DA-I Data Input Sheet Page 1 of 13 PROJECT: Job No.: BY:DATE:1/9/24 [1] AMC II [2] FREQUENCY-YEARS 100 FROM NOAA ATLAS 14 [3] STORM DURATION:Point Rain 1-HOUR 1.57 in 3-HOUR 2.27 in 6-HOUR 2.98 in 24-HOUR 4.59 in STORM DURATION 1-HOUR 3-HOUR 6-HOUR 24-HOUR RAINFALL VOLUME (cu-ft)7,586 10,968 14,398 22,177 SOIL LOSSES (cu-ft)3,254 7,395 10,790 18,980 EFFECTIVE RAIN (in)0.90 0.74 0.75 0.66 FLOOD VOLUME (cu-ft)4,332 3,573 3,608 3,197 (acre-ft)0.10 0.08 0.08 0.07 REQUIRED STORAGE (cu-ft)3,129 1,594 1,149 0 (acre-ft)0.07 0.04 0.03 0.00 FACTOR OF SAFETY 14.52 28.49 39.51 #DIV/0! STORAGE PROVIDED (cu-ft) (acre-ft) PEAK FLOW (cfs)n/a 2.09 1.78 0.11 MAXIMUM WSEL (ft)286.39 286.08 285.99 285.70 DEPTH (ft)0.69 0.38 0.29 0.00 DIFFERENCE (ft) DIFFERENCE (ft) ESTIMATED TIME TO DEWATER BASIN Based on Total Flood Volume & Average Percolation Rate (days)0.1 0.2 0.3 1.0 Retention Basin - I DA-I Del Webb Explore at Palm Desert [10] H-FEET [9] ELEVATION OF CONCENTRATION POINT 1.331 PHYSICAL DATA [1] CONCENTRATION POINT HYDROLOGY MANUAL BASIC DATA CALCULATION FORM 2636 RJB RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD [2] AREA DESIGNATION [3] AREA - ACRES [4] L-FEET [5] L-MILES 715 0.135 [13] L*LCA/S^0.5 6.26 [11] S-FEET/MILE [6] La-FEET [7] La-MILES [8] ELEVATION OF HEADWATER 0.015 3578.00 [12] S^0.5 0.678 39.1 296.3 291 5.3 0.02 [17] 100% OF LAG-MINUTES 5.8 5.8 [14] AVERAGE MANNINGS 'N' [15] LAG TIME-HOURS 0.10 [16] LAG TIME-MINUTES [18] 200% OF LAG-MINUTES RAINFALL DATA 11.6 NOTE: PEAK FLOW FOR THE 1-HOUR STORM IS NOT REPRESENTATIVE. PER RCFCD PEAK DISCHARGES FROM THE 3-HOUR STORM SHOULD NORMALLY COMPARE WELL WITH RATIONAL PEAKS. LOWEST PAD ELEVATION LOWEST FLOWLINE ELEVATION STORM EVENT SUMMARY 45,419 1.04 Plate E-2.1 Page 2 of 13 PROJECT: Job No.: BY:DATE:1/9/24 MAX LOW LOW MIN SOIL RI PERVIOUS DECIMAL ADJUSTED AREA AREA AVERAGE LOSS LOSS RATE AVERAGE GROUP NUMBER AREA PERCENT INFILTRATION WEIGHTED ADJUSTED CONDITION PER ADJUSTED INFILTRATION OF AREA RATE AVERAGE INFILTRATION RCFC/2322 INFILTRATION RATE IMPERVIOUS RATE RATE (in/hr)(in/hr)(in/hr) [Plate C-1][Plate E-6.1][Plate E-6.2][Plate E-6.3] A 32 0.74 10%0.67 1.331 1.000 0.6734 DEVELOPED 0.8200 0.8200 SUM 1.331 SUM 0.6734 0.8200 VARIABLE LOSS RATE CURVE (24-HOUR STORM ONLY) Fm=0.3367 NOTE: Low loss rates established per RCFC/2322 (Dated: May-30-95) C=0.00624 For 10 Year Storms or Less Ft=C(24-(T/60))^1.55+Fm =0.00624 0.34 in/hr Undeveloped Condition: Low Loss = 90% CONSTANT LOSS RATE (3 & 6 HOUR STORMS)=0.6734 Developed Condition: Low Loss = 0.9 - (0.8 * %impervious) LOW LOSS RATE =0.8500 Basin Site: Low Loss = 10% Where:For 100 Year Storm - Low Loss should be between 80% & 90% T=Time in minutes. To get an average value for each unit time period, Use T=1/2 the unit time for the first time period,of the Rainfall Rate T=1 1/2 unit time for the second period, etc. AVERAGE ADJUSTED LOSS RATE RCFC & WCD HYDROLOGY MANUAL SYNTHETIC UNIT HYDROGRAPH METHOD BASIC DATA CALCULATION FORM Del Webb Explore at Palm Desert RJB 2636 AMC II (24-(T/60))^1.55 + LAND USE LANDSCAPING Plate E-2.1 Page 3 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 1.33 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 5.79 Maxwell Drywells UNIT TIME-PERCENT OF LAG 86.4 Number 0 TOTAL ADJUSTED STORM RAIN-INCHES 1.57 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE-in/hr 0.67 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 5 0.08 3.6 0.68 0.67 0.58 0.00 0.01 2 2 3,786 131 2 0 0.00 285.70 2 10 0.17 4.2 0.79 0.67 0.67 0.12 0.16 47 47 3,803 132 47 0 0.00 285.70 3 15 0.25 4.4 0.83 0.67 0.70 0.16 0.21 63 63 3,809 132 63 0 0.00 285.70 4 20 0.33 4.6 0.87 0.67 0.74 0.19 0.26 78 78 3,814 132 78 0 0.00 285.70 5 25 0.42 5.0 0.94 0.67 0.80 0.27 0.36 108 108 3,826 133 108 0 0.00 285.70 6 30 0.50 5.6 1.06 0.67 0.90 0.38 0.51 154 154 3,843 133 133 20 0.00 285.71 7 35 0.58 6.4 1.21 0.67 1.02 0.53 0.71 214 235 3,874 135 135 100 0.00 285.72 8 40 0.67 8.1 1.53 0.67 1.30 0.85 1.14 343 443 3,953 137 137 306 0.01 285.78 9 45 0.75 13.1 2.47 0.67 2.10 1.79 2.41 723 1,029 4,175 145 145 884 0.02 285.92 10 50 0.83 34.5 6.50 0.67 5.52 5.83 7.82 2,346 3,230 4,853 169 169 3,061 0.07 286.37 11 55 0.92 6.7 1.26 0.67 1.07 0.59 0.79 237 3,298 4,874 169 169 3,129 0.07 286.39 12 60 1.00 3.8 0.72 0.67 0.61 0.04 0.06 17 3,146 4,828 168 168 2,978 0.07 286.36 TOTAL RAINFALL 1.57 in RAINFALL VOLUME 7,586 cu-ft SOIL LOSSES 3,254 cu-ft EFFECTIVE RAIN 0.90 in FLOOD VOLUME 0.10 acft FLOOD VOLUME 4,332 cu-ft REQUIRED STORAGE 0.07 REQUIRED STORAGE 3,129 cu-ft MAX WSEL 286.39 ft PEAK FLOW RATE 7.82 cfs TOTAL BASIN LOSSES 1,354 cu-ft AVERAGE PERCOLATION RATE 22.56 cf/min Del Webb Explore at Palm DesertRCFC & WCD HYDROLOGY MANUAL SYNTHETIC UNIT HYDROGRAPH METHOD SHORTCUT METHOD 1-HOUR STORM EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Total In Basin in/hr Time Loss Rate Basin Losses Plate E-2.2 1-Hour Storm Page 4 of 13 PROJECT: Job No.:2636 BY:RJB DATE DRAINAGE AREA-ACRES 1.33 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 5.79 Maxwell Drywells UNIT TIME-PERCENT OF LAG 86.4 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.27 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.67 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 5 0.08 1.3 0.35 0.67 0.30 0.05 0.07 21 21 3,793 132 21 0 0.00 285.70 2 10 0.17 1.3 0.35 0.67 0.30 0.05 0.07 21 21 3,793 132 21 0 0.00 285.70 3 15 0.25 1.1 0.30 0.67 0.25 0.04 0.06 18 18 3,792 132 18 0 0.00 285.70 4 20 0.33 1.5 0.41 0.67 0.35 0.06 0.08 25 25 3,794 132 25 0 0.00 285.70 5 25 0.42 1.5 0.41 0.67 0.35 0.06 0.08 25 25 3,794 132 25 0 0.00 285.70 6 30 0.50 1.8 0.49 0.67 0.42 0.07 0.10 30 30 3,796 132 30 0 0.00 285.70 7 35 0.58 1.5 0.41 0.67 0.35 0.06 0.08 25 25 3,794 132 25 0 0.00 285.70 8 40 0.67 1.8 0.49 0.67 0.42 0.07 0.10 30 30 3,796 132 30 0 0.00 285.70 9 45 0.75 1.8 0.49 0.67 0.42 0.07 0.10 30 30 3,796 132 30 0 0.00 285.70 10 50 0.83 1.5 0.41 0.67 0.35 0.06 0.08 25 25 3,794 132 25 0 0.00 285.70 11 55 0.92 1.6 0.44 0.67 0.37 0.07 0.09 26 26 3,795 132 26 0 0.00 285.70 12 60 1.00 1.8 0.49 0.67 0.42 0.07 0.10 30 30 3,796 132 30 0 0.00 285.70 13 65 1.08 2.2 0.60 0.67 0.51 0.09 0.12 36 36 3,799 132 36 0 0.00 285.70 14 70 1.17 2.2 0.60 0.67 0.51 0.09 0.12 36 36 3,799 132 36 0 0.00 285.70 15 75 1.25 2.2 0.60 0.67 0.51 0.09 0.12 36 36 3,799 132 36 0 0.00 285.70 16 80 1.33 2.0 0.54 0.67 0.46 0.08 0.11 33 33 3,797 132 33 0 0.00 285.70 17 85 1.42 2.6 0.71 0.67 0.60 0.03 0.05 14 14 3,790 132 14 0 0.00 285.70 18 90 1.50 2.7 0.74 0.67 0.63 0.06 0.08 25 25 3,794 132 25 0 0.00 285.70 19 95 1.58 2.4 0.65 0.67 0.56 0.10 0.13 39 39 3,800 132 39 0 0.00 285.70 20 100 1.67 2.7 0.74 0.67 0.63 0.06 0.08 25 25 3,794 132 25 0 0.00 285.70 21 105 1.75 3.3 0.90 0.67 0.76 0.23 0.30 91 91 3,819 133 91 0 0.00 285.70 22 110 1.83 3.1 0.84 0.67 0.72 0.17 0.23 69 69 3,811 132 69 0 0.00 285.70 23 115 1.92 2.9 0.79 0.67 0.67 0.12 0.16 47 47 3,803 132 47 0 0.00 285.70 24 120 2.00 3.0 0.82 0.67 0.69 0.14 0.19 58 58 3,807 132 58 0 0.00 285.70 25 125 2.08 3.1 0.84 0.67 0.72 0.17 0.23 69 69 3,811 132 69 0 0.00 285.70 Total In Basin in/hr MANUAL 3-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Loss Rate Basin Losses RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Plate E-2.2 3-Hour Storm Page 5 of 13 PROJECT: Job No.:2636 BY:RJB DATE DRAINAGE AREA-ACRES 1.33 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 5.79 Maxwell Drywells UNIT TIME-PERCENT OF LAG 86.4 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.27 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.67 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft Total In Basin in/hr MANUAL 3-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Loss Rate Basin Losses RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD 26 130 2.17 4.2 1.14 0.67 0.97 0.47 0.63 190 190 3,857 134 134 56 0.00 285.71 27 135 2.25 5.0 1.36 0.67 1.16 0.69 0.92 277 333 3,911 136 136 197 0.00 285.75 28 140 2.33 3.5 0.95 0.67 0.81 0.28 0.38 113 310 3,902 135 135 174 0.00 285.74 29 145 2.42 6.8 1.85 0.67 1.57 1.18 1.58 475 649 4,031 140 140 509 0.01 285.83 30 150 2.50 7.3 1.99 0.67 1.69 1.32 1.77 530 1,038 4,179 145 145 893 0.02 285.92 31 155 2.58 8.2 2.23 0.67 1.90 1.56 2.09 628 1,522 4,337 151 151 1,371 0.03 286.03 32 160 2.67 5.9 1.61 0.67 1.37 0.93 1.25 376 1,747 4,405 153 153 1,594 0.04 286.08 33 165 2.75 2.0 0.54 0.67 0.46 0.08 0.11 33 1,627 4,369 152 152 1,475 0.03 286.05 34 170 2.83 1.8 0.49 0.67 0.42 0.07 0.10 30 1,505 4,332 150 150 1,354 0.03 286.03 35 175 2.92 1.8 0.49 0.67 0.42 0.07 0.10 30 1,384 4,296 149 149 1,235 0.03 286.01 36 180 3.00 0.6 0.16 0.67 0.14 0.02 0.03 10 1,245 4,254 148 148 1,097 0.03 285.97 TOTAL RAIN RAINFALL VOLUME SOIL LOSSES EFFECTIVE RAIN FLOOD VOLUME FLOOD VOLUME REQUIRED STORAGE REQUIRED STORAGE MAX WSEL PEAK FLOW RATE TOTAL BASIN LOSSES AVERAGE PERCOLATION RATE 7,395 cu-ft 2.27 in 10,968 cu-ft 286.08 ft 2.09 cfs 2,475 cu-ft 13.75 cf/min 0.74 in 0.08 acft 3,573 cu-ft 0.04 acft 1,594 cu-ft EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY Plate E-2.2 3-Hour Storm Page 6 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 1.33 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 5.79 Maxwell Drywells UNIT TIME-PERCENT OF LAG 86.4 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.98 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.67 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 5 0.08 0.5 0.18 0.67 0.15 0.03 0.04 11 11 3,789 132 11 0 0.00 285.70 2 10 0.17 0.6 0.21 0.67 0.18 0.03 0.04 13 13 3,790 132 13 0 0.00 285.70 3 15 0.25 0.6 0.21 0.67 0.18 0.03 0.04 13 13 3,790 132 13 0 0.00 285.70 4 20 0.33 0.6 0.21 0.67 0.18 0.03 0.04 13 13 3,790 132 13 0 0.00 285.70 5 25 0.42 0.6 0.21 0.67 0.18 0.03 0.04 13 13 3,790 132 13 0 0.00 285.70 6 30 0.50 0.7 0.25 0.67 0.21 0.04 0.05 15 15 3,791 132 15 0 0.00 285.70 7 35 0.58 0.7 0.25 0.67 0.21 0.04 0.05 15 15 3,791 132 15 0 0.00 285.70 8 40 0.67 0.7 0.25 0.67 0.21 0.04 0.05 15 15 3,791 132 15 0 0.00 285.70 9 45 0.75 0.7 0.25 0.67 0.21 0.04 0.05 15 15 3,791 132 15 0 0.00 285.70 10 50 0.83 0.7 0.25 0.67 0.21 0.04 0.05 15 15 3,791 132 15 0 0.00 285.70 11 55 0.92 0.7 0.25 0.67 0.21 0.04 0.05 15 15 3,791 132 15 0 0.00 285.70 12 60 1.00 0.8 0.29 0.67 0.24 0.04 0.06 17 17 3,792 132 17 0 0.00 285.70 13 65 1.08 0.8 0.29 0.67 0.24 0.04 0.06 17 17 3,792 132 17 0 0.00 285.70 14 70 1.17 0.8 0.29 0.67 0.24 0.04 0.06 17 17 3,792 132 17 0 0.00 285.70 15 75 1.25 0.8 0.29 0.67 0.24 0.04 0.06 17 17 3,792 132 17 0 0.00 285.70 16 80 1.33 0.8 0.29 0.67 0.24 0.04 0.06 17 17 3,792 132 17 0 0.00 285.70 17 85 1.42 0.8 0.29 0.67 0.24 0.04 0.06 17 17 3,792 132 17 0 0.00 285.70 18 90 1.50 0.8 0.29 0.67 0.24 0.04 0.06 17 17 3,792 132 17 0 0.00 285.70 19 95 1.58 0.8 0.29 0.67 0.24 0.04 0.06 17 17 3,792 132 17 0 0.00 285.70 20 100 1.67 0.8 0.29 0.67 0.24 0.04 0.06 17 17 3,792 132 17 0 0.00 285.70 21 105 1.75 0.8 0.29 0.67 0.24 0.04 0.06 17 17 3,792 132 17 0 0.00 285.70 22 110 1.83 0.8 0.29 0.67 0.24 0.04 0.06 17 17 3,792 132 17 0 0.00 285.70 23 115 1.92 0.8 0.29 0.67 0.24 0.04 0.06 17 17 3,792 132 17 0 0.00 285.70 24 120 2.00 0.9 0.32 0.67 0.27 0.05 0.06 19 19 3,792 132 19 0 0.00 285.70 Loss Rate RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 6-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Basin Losses Plate E-2.2 6-Hour Storm Page 7 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 1.33 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 5.79 Maxwell Drywells UNIT TIME-PERCENT OF LAG 86.4 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.98 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.67 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft Loss Rate RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 6-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Basin Losses 25 125 2.08 0.8 0.29 0.67 0.24 0.04 0.06 17 17 3,792 132 17 0 0.00 285.70 26 130 2.17 0.9 0.32 0.67 0.27 0.05 0.06 19 19 3,792 132 19 0 0.00 285.70 27 135 2.25 0.9 0.32 0.67 0.27 0.05 0.06 19 19 3,792 132 19 0 0.00 285.70 28 140 2.33 0.9 0.32 0.67 0.27 0.05 0.06 19 19 3,792 132 19 0 0.00 285.70 29 145 2.42 0.9 0.32 0.67 0.27 0.05 0.06 19 19 3,792 132 19 0 0.00 285.70 30 150 2.50 0.9 0.32 0.67 0.27 0.05 0.06 19 19 3,792 132 19 0 0.00 285.70 31 155 2.58 0.9 0.32 0.67 0.27 0.05 0.06 19 19 3,792 132 19 0 0.00 285.70 32 160 2.67 0.9 0.32 0.67 0.27 0.05 0.06 19 19 3,792 132 19 0 0.00 285.70 33 165 2.75 1.0 0.36 0.67 0.30 0.05 0.07 22 22 3,793 132 22 0 0.00 285.70 34 170 2.83 1.0 0.36 0.67 0.30 0.05 0.07 22 22 3,793 132 22 0 0.00 285.70 35 175 2.92 1.0 0.36 0.67 0.30 0.05 0.07 22 22 3,793 132 22 0 0.00 285.70 36 180 3.00 1.0 0.36 0.67 0.30 0.05 0.07 22 22 3,793 132 22 0 0.00 285.70 37 185 3.08 1.0 0.36 0.67 0.30 0.05 0.07 22 22 3,793 132 22 0 0.00 285.70 38 190 3.17 1.1 0.39 0.67 0.33 0.06 0.08 24 24 3,794 132 24 0 0.00 285.70 39 195 3.25 1.1 0.39 0.67 0.33 0.06 0.08 24 24 3,794 132 24 0 0.00 285.70 40 200 3.33 1.1 0.39 0.67 0.33 0.06 0.08 24 24 3,794 132 24 0 0.00 285.70 41 205 3.42 1.2 0.43 0.67 0.36 0.06 0.09 26 26 3,795 132 26 0 0.00 285.70 42 210 3.50 1.3 0.46 0.67 0.40 0.07 0.09 28 28 3,796 132 28 0 0.00 285.70 43 215 3.58 1.4 0.50 0.67 0.43 0.08 0.10 30 30 3,796 132 30 0 0.00 285.70 44 220 3.67 1.4 0.50 0.67 0.43 0.08 0.10 30 30 3,796 132 30 0 0.00 285.70 45 225 3.75 1.5 0.54 0.67 0.46 0.08 0.11 32 32 3,797 132 32 0 0.00 285.70 46 230 3.83 1.5 0.54 0.67 0.46 0.08 0.11 32 32 3,797 132 32 0 0.00 285.70 47 235 3.92 1.6 0.57 0.67 0.49 0.09 0.12 35 35 3,798 132 35 0 0.00 285.70 48 240 4.00 1.6 0.57 0.67 0.49 0.09 0.12 35 35 3,798 132 35 0 0.00 285.70 49 245 4.08 1.7 0.61 0.67 0.52 0.09 0.12 37 37 3,799 132 37 0 0.00 285.70 50 250 4.17 1.8 0.64 0.67 0.55 0.10 0.13 39 39 3,800 132 39 0 0.00 285.70 Plate E-2.2 6-Hour Storm Page 8 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 1.33 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 5.79 Maxwell Drywells UNIT TIME-PERCENT OF LAG 86.4 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.98 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.67 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft Loss Rate RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 6-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Basin Losses 51 255 4.25 1.9 0.68 0.67 0.58 0.01 0.01 2 2 3,786 131 2 0 0.00 285.70 52 260 4.33 2.0 0.72 0.67 0.61 0.04 0.06 17 17 3,791 132 17 0 0.00 285.70 53 265 4.42 2.1 0.75 0.67 0.64 0.08 0.10 31 31 3,797 132 31 0 0.00 285.70 54 270 4.50 2.1 0.75 0.67 0.64 0.08 0.10 31 31 3,797 132 31 0 0.00 285.70 55 275 4.58 2.2 0.79 0.67 0.67 0.11 0.15 46 46 3,802 132 46 0 0.00 285.70 56 280 4.67 2.3 0.82 0.67 0.70 0.15 0.20 60 60 3,808 132 60 0 0.00 285.70 57 285 4.75 2.4 0.86 0.67 0.73 0.18 0.25 74 74 3,813 132 74 0 0.00 285.70 58 290 4.83 2.4 0.86 0.67 0.73 0.18 0.25 74 74 3,813 132 74 0 0.00 285.70 59 295 4.92 2.5 0.89 0.67 0.76 0.22 0.30 89 89 3,819 133 89 0 0.00 285.70 60 300 5.00 2.6 0.93 0.67 0.79 0.26 0.34 103 103 3,824 133 103 0 0.00 285.70 61 305 5.08 3.1 1.11 0.67 0.94 0.44 0.58 175 175 3,851 134 134 41 0.00 285.71 62 310 5.17 3.6 1.29 0.67 1.09 0.61 0.82 247 289 3,894 135 135 153 0.00 285.74 63 315 5.25 3.9 1.39 0.67 1.19 0.72 0.97 290 444 3,953 137 137 307 0.01 285.78 64 320 5.33 4.2 1.50 0.67 1.28 0.83 1.11 334 640 4,028 140 140 500 0.01 285.82 65 325 5.42 4.7 1.68 0.67 1.43 1.01 1.35 406 906 4,128 143 143 763 0.02 285.89 66 330 5.50 5.6 2.00 0.67 1.70 1.33 1.78 535 1,298 4,270 148 148 1,149 0.03 285.99 67 335 5.58 1.9 0.68 0.67 0.58 0.01 0.01 2 1,152 4,222 147 147 1,005 0.02 285.95 68 340 5.67 0.9 0.32 0.67 0.27 0.05 0.06 19 1,025 4,173 145 145 880 0.02 285.92 69 345 5.75 0.6 0.21 0.67 0.18 0.03 0.04 13 893 4,123 143 143 750 0.02 285.89 70 350 5.83 0.5 0.18 0.67 0.15 0.03 0.04 11 760 4,073 141 141 619 0.01 285.85 71 355 5.92 0.3 0.11 0.67 0.09 0.02 0.02 6 625 4,022 140 140 486 0.01 285.82 72 360 6.00 0.2 0.07 0.67 0.06 0.01 0.01 4 490 3,971 138 138 352 0.01 285.79 TOTAL RAINFALL RAINFALL VOLUME SOIL LOSSES EFFECTIVE RAIN FLOOD VOLUME FLOOD VOLUME REQUIRED STORAGE REQUIRED STORAGE MAX WSEL PEAK FLOW RATE TOTAL BASIN LOSSES AVERAGE PERCOLATION RATE 14,398 cu-ft 2.98 in 10,790 cu-ft 285.99 ft 1.78 cfs 9.04 cf/min 3,256 cu-ft 0.75 in 0.08 acft 3,608 cu-ft 0.03 acft 1,149 cu-ft EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY Plate E-2.2 6-Hour Storm Page 9 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 1.33 VARIABLE LOSS RATE (AVG) IN/HR Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 15 Fm = Minimum value on loss curve (in/hr)0.34 LAG TIME - MINUTES 5.79 C 0.00624 Maxwell Drywells UNIT TIME-PERCENT OF LAG 259%Low Loss Rate (percent)85.00%Number 0 TOTAL ADJUSTED STORM RAIN (in)4.59 Drywell Percolation Rate 0.00 cfs 0.00 cfm Unit Time Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 15 0.25 0.2 0.037 1.189 0.031 0.01 0.01 7 7 3,788 395 7 0 0.00 285.70 2 30 0.50 0.3 0.055 1.175 0.047 0.01 0.01 10 10 3,789 395 10 0 0.00 285.70 3 45 0.75 0.3 0.055 1.162 0.047 0.01 0.01 10 10 3,789 395 10 0 0.00 285.70 4 60 1.00 0.4 0.073 1.148 0.062 0.01 0.01 13 13 3,790 395 13 0 0.00 285.70 5 75 1.25 0.3 0.055 1.134 0.047 0.01 0.01 10 10 3,789 395 10 0 0.00 285.70 6 90 1.50 0.3 0.055 1.121 0.047 0.01 0.01 10 10 3,789 395 10 0 0.00 285.70 7 105 1.75 0.3 0.055 1.108 0.047 0.01 0.01 10 10 3,789 395 10 0 0.00 285.70 8 120 2.00 0.4 0.073 1.094 0.062 0.01 0.01 13 13 3,790 395 13 0 0.00 285.70 9 135 2.25 0.4 0.073 1.081 0.062 0.01 0.01 13 13 3,790 395 13 0 0.00 285.70 10 150 2.50 0.4 0.073 1.068 0.062 0.01 0.01 13 13 3,790 395 13 0 0.00 285.70 11 165 2.75 0.5 0.092 1.055 0.078 0.01 0.02 17 17 3,791 395 17 0 0.00 285.70 12 180 3.00 0.5 0.092 1.042 0.078 0.01 0.02 17 17 3,791 395 17 0 0.00 285.70 13 195 3.25 0.5 0.092 1.029 0.078 0.01 0.02 17 17 3,791 395 17 0 0.00 285.70 14 210 3.50 0.5 0.092 1.016 0.078 0.01 0.02 17 17 3,791 395 17 0 0.00 285.70 15 225 3.75 0.5 0.092 1.003 0.078 0.01 0.02 17 17 3,791 395 17 0 0.00 285.70 16 240 4.00 0.6 0.110 0.991 0.094 0.02 0.02 20 20 3,793 395 20 0 0.00 285.70 17 255 4.25 0.6 0.110 0.978 0.094 0.02 0.02 20 20 3,793 395 20 0 0.00 285.70 18 270 4.50 0.7 0.129 0.966 0.109 0.02 0.03 23 23 3,794 395 23 0 0.00 285.70 19 285 4.75 0.7 0.129 0.953 0.109 0.02 0.03 23 23 3,794 395 23 0 0.00 285.70 20 300 5.00 0.8 0.147 0.941 0.125 0.02 0.03 27 27 3,795 395 27 0 0.00 285.70 21 315 5.25 0.6 0.110 0.929 0.094 0.02 0.02 20 20 3,793 395 20 0 0.00 285.70 22 330 5.50 0.7 0.129 0.917 0.109 0.02 0.03 23 23 3,794 395 23 0 0.00 285.70 23 345 5.75 0.8 0.147 0.905 0.125 0.02 0.03 27 27 3,795 395 27 0 0.00 285.70 24 360 6.00 0.8 0.147 0.893 0.125 0.02 0.03 27 27 3,795 395 27 0 0.00 285.70 25 375 6.25 0.9 0.165 0.881 0.140 0.02 0.03 30 30 3,796 395 30 0 0.00 285.70 26 390 6.50 0.9 0.165 0.869 0.140 0.02 0.03 30 30 3,796 395 30 0 0.00 285.70 27 405 6.75 1.0 0.184 0.858 0.156 0.03 0.04 33 33 3,798 396 33 0 0.00 285.70 28 420 7.00 1.0 0.184 0.846 0.156 0.03 0.04 33 33 3,798 396 33 0 0.00 285.70 29 435 7.25 1.0 0.184 0.835 0.156 0.03 0.04 33 33 3,798 396 33 0 0.00 285.70 30 450 7.50 1.1 0.202 0.823 0.172 0.03 0.04 37 37 3,799 396 37 0 0.00 285.70 31 465 7.75 1.2 0.220 0.812 0.187 0.03 0.04 40 40 3,800 396 40 0 0.00 285.70 32 480 8.00 1.3 0.239 0.801 0.203 0.04 0.05 43 43 3,801 396 43 0 0.00 285.70 33 495 8.25 1.5 0.275 0.790 0.234 0.04 0.06 50 50 3,804 396 50 0 0.00 285.70 34 510 8.50 1.5 0.275 0.779 0.234 0.04 0.06 50 50 3,804 396 50 0 0.00 285.70 35 525 8.75 1.6 0.294 0.768 0.250 0.04 0.06 53 53 3,805 396 53 0 0.00 285.70 36 540 9.00 1.7 0.312 0.757 0.265 0.05 0.06 57 57 3,806 397 57 0 0.00 285.70 37 555 9.25 1.9 0.349 0.746 0.297 0.05 0.07 63 63 3,809 397 63 0 0.00 285.70 38 570 9.50 2.0 0.367 0.735 0.312 0.06 0.07 67 67 3,810 397 67 0 0.00 285.70 39 585 9.75 2.1 0.386 0.725 0.328 0.06 0.08 70 70 3,811 397 70 0 0.00 285.70 40 600 10.00 2.2 0.404 0.715 0.343 0.06 0.08 73 73 3,813 397 73 0 0.00 285.70 41 615 10.25 1.5 0.275 0.704 0.234 0.04 0.06 50 50 3,804 396 50 0 0.00 285.70 42 630 10.50 1.5 0.275 0.694 0.234 0.04 0.06 50 50 3,804 396 50 0 0.00 285.70 43 645 10.75 2.0 0.367 0.684 0.312 0.06 0.07 67 67 3,810 397 67 0 0.00 285.70 RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Loss Rate Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD MANUAL 24-HOUR STORM Basin Losses in/hr Total In Basin UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Plate E-2.2 24-Hour Storm Page 10 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 1.33 VARIABLE LOSS RATE (AVG) IN/HR Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 15 Fm = Minimum value on loss curve (in/hr)0.34 LAG TIME - MINUTES 5.79 C 0.00624 Maxwell Drywells UNIT TIME-PERCENT OF LAG 259%Low Loss Rate (percent)85.00%Number 0 TOTAL ADJUSTED STORM RAIN (in)4.59 Drywell Percolation Rate 0.00 cfs 0.00 cfm Unit Time Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Loss Rate Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD MANUAL 24-HOUR STORM Basin Losses in/hr Total In Basin UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM 44 660 11.00 2.0 0.367 0.674 0.312 0.06 0.07 67 67 3,810 397 67 0 0.00 285.70 45 675 11.25 1.9 0.349 0.664 0.297 0.05 0.07 63 63 3,809 397 63 0 0.00 285.70 46 690 11.50 1.9 0.349 0.654 0.297 0.05 0.07 63 63 3,809 397 63 0 0.00 285.70 47 705 11.75 1.7 0.312 0.645 0.265 0.05 0.06 57 57 3,806 397 57 0 0.00 285.70 48 720 12.00 1.8 0.330 0.635 0.281 0.05 0.07 60 60 3,808 397 60 0 0.00 285.70 49 735 12.25 2.5 0.459 0.625 0.390 0.07 0.09 83 83 3,817 398 83 0 0.00 285.70 50 750 12.50 2.6 0.477 0.616 0.406 0.07 0.10 86 86 3,818 398 86 0 0.00 285.70 51 765 12.75 2.8 0.514 0.607 0.437 0.08 0.10 93 93 3,820 398 93 0 0.00 285.70 52 780 13.00 2.9 0.532 0.598 0.453 0.08 0.11 96 96 3,822 398 96 0 0.00 285.70 53 795 13.25 3.4 0.624 0.589 0.531 0.04 0.05 43 43 3,801 396 43 0 0.00 285.70 54 810 13.50 3.4 0.624 0.580 0.531 0.04 0.06 54 54 3,805 396 54 0 0.00 285.70 55 825 13.75 2.3 0.422 0.571 0.359 0.06 0.09 77 77 3,814 397 77 0 0.00 285.70 56 840 14.00 2.3 0.422 0.562 0.359 0.06 0.09 77 77 3,814 397 77 0 0.00 285.70 57 855 14.25 2.7 0.496 0.554 0.421 0.07 0.10 90 90 3,819 398 90 0 0.00 285.70 58 870 14.50 2.6 0.477 0.545 0.406 0.07 0.10 86 86 3,818 398 86 0 0.00 285.70 59 885 14.75 2.6 0.477 0.537 0.406 0.07 0.10 86 86 3,818 398 86 0 0.00 285.70 60 900 15.00 2.5 0.459 0.529 0.390 0.07 0.09 83 83 3,817 398 83 0 0.00 285.70 61 915 15.25 2.4 0.441 0.521 0.375 0.07 0.09 80 80 3,815 397 80 0 0.00 285.70 62 930 15.50 2.3 0.422 0.513 0.359 0.06 0.09 77 77 3,814 397 77 0 0.00 285.70 63 945 15.75 1.9 0.349 0.505 0.297 0.05 0.07 63 63 3,809 397 63 0 0.00 285.70 64 960 16.00 1.9 0.349 0.497 0.297 0.05 0.07 63 63 3,809 397 63 0 0.00 285.70 65 975 16.25 0.4 0.073 0.489 0.062 0.01 0.01 13 13 3,790 395 13 0 0.00 285.70 66 990 16.50 0.4 0.073 0.482 0.062 0.01 0.01 13 13 3,790 395 13 0 0.00 285.70 67 1005 16.75 0.3 0.055 0.475 0.047 0.01 0.01 10 10 3,789 395 10 0 0.00 285.70 68 1020 17.00 0.3 0.055 0.468 0.047 0.01 0.01 10 10 3,789 395 10 0 0.00 285.70 69 1035 17.25 0.5 0.092 0.460 0.078 0.01 0.02 17 17 3,791 395 17 0 0.00 285.70 70 1050 17.50 0.5 0.092 0.454 0.078 0.01 0.02 17 17 3,791 395 17 0 0.00 285.70 71 1065 17.75 0.5 0.092 0.447 0.078 0.01 0.02 17 17 3,791 395 17 0 0.00 285.70 72 1080 18.00 0.4 0.073 0.440 0.062 0.01 0.01 13 13 3,790 395 13 0 0.00 285.70 73 1095 18.25 0.4 0.073 0.434 0.062 0.01 0.01 13 13 3,790 395 13 0 0.00 285.70 74 1110 18.50 0.4 0.073 0.427 0.062 0.01 0.01 13 13 3,790 395 13 0 0.00 285.70 75 1125 18.75 0.3 0.055 0.421 0.047 0.01 0.01 10 10 3,789 395 10 0 0.00 285.70 76 1140 19.00 0.2 0.037 0.415 0.031 0.01 0.01 7 7 3,788 395 7 0 0.00 285.70 77 1155 19.25 0.3 0.055 0.409 0.047 0.01 0.01 10 10 3,789 395 10 0 0.00 285.70 78 1170 19.50 0.4 0.073 0.404 0.062 0.01 0.01 13 13 3,790 395 13 0 0.00 285.70 79 1185 19.75 0.3 0.055 0.398 0.047 0.01 0.01 10 10 3,789 395 10 0 0.00 285.70 80 1200 20.00 0.2 0.037 0.393 0.031 0.01 0.01 7 7 3,788 395 7 0 0.00 285.70 81 1215 20.25 0.3 0.055 0.388 0.047 0.01 0.01 10 10 3,789 395 10 0 0.00 285.70 82 1230 20.50 0.3 0.055 0.383 0.047 0.01 0.01 10 10 3,789 395 10 0 0.00 285.70 83 1245 20.75 0.3 0.055 0.378 0.047 0.01 0.01 10 10 3,789 395 10 0 0.00 285.70 84 1260 21.00 0.2 0.037 0.373 0.031 0.01 0.01 7 7 3,788 395 7 0 0.00 285.70 85 1275 21.25 0.3 0.055 0.369 0.047 0.01 0.01 10 10 3,789 395 10 0 0.00 285.70 86 1290 21.50 0.2 0.037 0.365 0.031 0.01 0.01 7 7 3,788 395 7 0 0.00 285.70 Plate E-2.2 24-Hour Storm Page 11 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 1.33 VARIABLE LOSS RATE (AVG) IN/HR Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 15 Fm = Minimum value on loss curve (in/hr)0.34 LAG TIME - MINUTES 5.79 C 0.00624 Maxwell Drywells UNIT TIME-PERCENT OF LAG 259%Low Loss Rate (percent)85.00%Number 0 TOTAL ADJUSTED STORM RAIN (in)4.59 Drywell Percolation Rate 0.00 cfs 0.00 cfm Unit Time Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Loss Rate Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD MANUAL 24-HOUR STORM Basin Losses in/hr Total In Basin UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM 87 1305 21.75 0.3 0.055 0.361 0.047 0.01 0.01 10 10 3,789 395 10 0 0.00 285.70 88 1320 22.00 0.2 0.037 0.357 0.031 0.01 0.01 7 7 3,788 395 7 0 0.00 285.70 89 1335 22.25 0.3 0.055 0.353 0.047 0.01 0.01 10 10 3,789 395 10 0 0.00 285.70 90 1350 22.50 0.2 0.037 0.350 0.031 0.01 0.01 7 7 3,788 395 7 0 0.00 285.70 91 1365 22.75 0.2 0.037 0.347 0.031 0.01 0.01 7 7 3,788 395 7 0 0.00 285.70 92 1380 23.00 0.2 0.037 0.344 0.031 0.01 0.01 7 7 3,788 395 7 0 0.00 285.70 93 1395 23.25 0.2 0.037 0.342 0.031 0.01 0.01 7 7 3,788 395 7 0 0.00 285.70 94 1410 23.50 0.2 0.037 0.340 0.031 0.01 0.01 7 7 3,788 395 7 0 0.00 285.70 95 1425 23.75 0.2 0.037 0.338 0.031 0.01 0.01 7 7 3,788 395 7 0 0.00 285.70 96 1440 24.00 0.2 0.037 0.337 0.031 0.01 0.01 7 7 3,788 395 7 0 0.00 285.70 EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY TOTAL RAINFALL RAINFALL VOLUME SOIL LOSSES EFFECTIVE RAIN FLOOD VOLUME FLOOD VOLUME REQUIRED STORAGE REQUIRED STORAGE MAX WSEL PEAK FLOW RATE TOTAL BASIN LOSSES AVERAGE PERCOLATION RATE 4.59 in 22,177 cu-ft 18,980 cu-ft 285.70 ft 0.11 cfs 3,197 cu-ft 2.22 cf/min 0.66 in 0.07 acft 3,197 cu-ft 0.00 acft 0 cu-ft Plate E-2.2 24-Hour Storm Page 12 of 13 PROECT JOB No. BASIN DESIGNATION: BASIN CHARACTERISTICS CONTOUR ELEVATION INCR TOTAL INCR TOTAL INCR (ft)(ft)(sf)(sf)(cuft)(cuft)(acre-ft) 285.7 0 0 3,785 0 0 0.00 286 0.3 0.3 456 4,241 1,203 1,203 0.03 287 1 1.3 1,502 5,743 4,973 6,176 0.14 288 1 2.3 1,738 7,481 6,593 12,769 0.29 289 1 3.3 2,057 9,538 8,489 21,258 0.49 290 1 4.3 2,433 11,971 10,731 31,989 0.73 291 1 5.3 2,973 14,944 13,430 45,419 1.04 WHERE: TOTAL Retention Basin - I BASIN VOLUME WORKSHEET DEPTH AREA VOLUME Del Webb Explore at Palm Desert 2636 ()()2121213 1 AAAAEEV++−= Basin Volume Worksheet Page 13 of 13 RJB 2 AMC II AREA SOIL TRIBUTARY AREAS ACRES LOW LOSS RI INFILTRATION IMPERVIOUS DESIG GROUP CONDITION NUMBER RATE PERCENT 5 A SF - ATTACHED 14.282 D 32 0.74 0.65 1,010 ft 505 ft 310.0 ft ELEVATION OF CONCENTRATION POINT 290.7 ft 0.02 100 LOW LOSS RATE (Storm Events > 10 Years)85% POINT RAIN FROM NOAA ATLAS 14 1-HOUR 1.57 in 3-HOUR 2.27 in 6-HOUR 2.98 in 24-HOUR 4.59 in BASIN CHARACTERISTICS:ELEVATION AREA 283.0 ft 12,844 sf 284.0 ft 28,951 sf 285.0 ft 32,230 sf 286.0 ft 35,631 sf 287.0 ft 39,156 sf 288.0 ft 42,794 sf PERCOLATION RATE (in/hr)5.0 in/hr DRYWELL DATA NUMBER USED PERCOLATION RATE LOWEST FLOWLINE ELEVATION LOWEST PAD ELEVATION LENGTH OF WATERCOURSE (L) AREA DESIGNATION ELEVATION OF HEADWATER AVERAGE MANNINGS 'N' VALUE STORM FREQUENCY (YEAR) LENGTH TO POINT OPPOSITE CENTROID (Lca) Low Loss Conditions: X=Existing; D=Developed; BS=Retention DA-J RCFCD SYNTHETIC UNIT HYDROGRAPH - SHORTCUT METHOD DATA INPUT SHEET WORKSHEET PREPARED BY: PROJECT NAME DATE January 9, 2024 Del Webb Explore at Palm Desert PROJECT NUMBER CONCENTRATION POINT DESIGNATION 2636 Retention Basin - J AMC NUMBER Data Input Sheet Page 1 of 13 PROJECT: Job No.: BY:DATE:1/9/24 [1] AMC II [2] FREQUENCY-YEARS 100 FROM NOAA ATLAS 14 [3] STORM DURATION:Point Rain 1-HOUR 1.57 in 3-HOUR 2.27 in 6-HOUR 2.98 in 24-HOUR 4.59 in STORM DURATION 1-HOUR 3-HOUR 6-HOUR 24-HOUR RAINFALL VOLUME (cu-ft)81,396 117,687 154,497 237,967 SOIL LOSSES (cu-ft)15,921 46,811 83,461 173,226 EFFECTIVE RAIN (in)1.26 1.37 1.37 1.25 FLOOD VOLUME (cu-ft)65,475 70,876 71,036 64,740 (acre-ft)1.50 1.63 1.63 1.49 REQUIRED STORAGE (cu-ft)55,542 47,141 43,430 11,514 (acre-ft)1.28 1.08 1.00 0.26 FACTOR OF SAFETY 2.94 3.46 3.76 14.17 STORAGE PROVIDED (cu-ft) (acre-ft) PEAK FLOW (cfs)n/a 27.75 24.42 5.18 MAXIMUM WSEL (ft)285.14 284.88 284.75 283.57 DEPTH (ft)2.14 1.88 1.75 0.57 DIFFERENCE (ft) DIFFERENCE (ft) ESTIMATED TIME TO DEWATER BASIN Based on Total Flood Volume & Average Percolation Rate (days)0.3 0.3 0.5 1.0 [18] 200% OF LAG-MINUTES RAINFALL DATA 5.2 NOTE: PEAK FLOW FOR THE 1-HOUR STORM IS NOT REPRESENTATIVE. PER RCFCD PEAK DISCHARGES FROM THE 3-HOUR STORM SHOULD NORMALLY COMPARE WELL WITH RATIONAL PEAKS. LOWEST PAD ELEVATION LOWEST FLOWLINE ELEVATION STORM EVENT SUMMARY 163,193 3.75 0.02 [17] 100% OF LAG-MINUTES 2.6 2.6 [14] AVERAGE MANNINGS 'N' [15] LAG TIME-HOURS 0.04 [16] LAG TIME-MINUTES [13] L*LCA/S^0.5 10.04 [11] S-FEET/MILE [6] La-FEET [7] La-MILES [8] ELEVATION OF HEADWATER 0.002 505.00 [12] S^0.5 0.096 100.9 310 290.7 19.3 [3] AREA - ACRES [4] L-FEET [5] L-MILES 1010 0.191 Retention Basin - J DA-J Del Webb Explore at Palm Desert [10] H-FEET [9] ELEVATION OF CONCENTRATION POINT 14.282 PHYSICAL DATA [1] CONCENTRATION POINT HYDROLOGY MANUAL BASIC DATA CALCULATION FORM 2636 RJB RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD [2] AREA DESIGNATION Plate E-2.1 Page 2 of 13 PROJECT: Job No.: BY:DATE:1/9/24 MAX LOW LOW MIN SOIL RI PERVIOUS DECIMAL ADJUSTED AREA AREA AVERAGE LOSS LOSS RATE AVERAGE GROUP NUMBER AREA PERCENT INFILTRATION WEIGHTED ADJUSTED CONDITION PER ADJUSTED INFILTRATION OF AREA RATE AVERAGE INFILTRATION RCFC/2322 INFILTRATION RATE IMPERVIOUS RATE RATE (in/hr)(in/hr)(in/hr) [Plate C-1][Plate E-6.1][Plate E-6.2][Plate E-6.3] A 32 0.74 65%0.31 14.282 1.000 0.3071 DEVELOPED 0.3800 0.3800 SUM 14.282 SUM 0.3071 0.3800 VARIABLE LOSS RATE CURVE (24-HOUR STORM ONLY) Fm=0.15355 NOTE: Low loss rates established per RCFC/2322 (Dated: May-30-95) C=0.00284 For 10 Year Storms or Less Ft=C(24-(T/60))^1.55+Fm =0.00284 0.15 in/hr Undeveloped Condition: Low Loss = 90% CONSTANT LOSS RATE (3 & 6 HOUR STORMS)=0.3071 Developed Condition: Low Loss = 0.9 - (0.8 * %impervious) LOW LOSS RATE =0.8500 Basin Site: Low Loss = 10% Where:For 100 Year Storm - Low Loss should be between 80% & 90% T=Time in minutes. To get an average value for each unit time period, Use T=1/2 the unit time for the first time period,of the Rainfall Rate T=1 1/2 unit time for the second period, etc. (24-(T/60))^1.55 + LAND USE SF - ATTACHED AVERAGE ADJUSTED LOSS RATE RCFC & WCD HYDROLOGY MANUAL SYNTHETIC UNIT HYDROGRAPH METHOD BASIC DATA CALCULATION FORM Del Webb Explore at Palm Desert RJB 2636 AMC II Plate E-2.1 Page 3 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 14.28 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 2.62 Maxwell Drywells UNIT TIME-PERCENT OF LAG 190.8 Number 0 TOTAL ADJUSTED STORM RAIN-INCHES 1.57 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE-in/hr 0.31 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 5 0.08 3.6 0.68 0.31 0.58 0.37 5.34 1,603 1,603 14,113 490 490 1,113 0.03 283.05 2 10 0.17 4.2 0.79 0.31 0.67 0.48 6.97 2,092 3,205 15,380 534 534 2,671 0.06 283.13 3 15 0.25 4.4 0.83 0.31 0.70 0.52 7.52 2,255 4,926 16,741 581 581 4,345 0.10 283.21 4 20 0.33 4.6 0.87 0.31 0.74 0.56 8.06 2,417 6,762 18,194 632 632 6,130 0.14 283.30 5 25 0.42 5.0 0.94 0.31 0.80 0.63 9.14 2,743 8,873 19,864 690 690 8,184 0.19 283.40 6 30 0.50 5.6 1.06 0.31 0.90 0.75 10.77 3,231 11,415 21,875 760 760 10,655 0.24 283.52 7 35 0.58 6.4 1.21 0.31 1.02 0.90 12.94 3,883 14,538 24,345 845 845 13,693 0.31 283.67 8 40 0.67 8.1 1.53 0.31 1.30 1.22 17.55 5,266 18,959 27,843 967 967 17,992 0.41 283.88 9 45 0.75 13.1 2.47 0.31 2.10 2.16 31.12 9,336 27,328 29,698 1,031 1,031 26,297 0.60 284.19 10 50 0.83 34.5 6.50 0.31 5.52 6.19 89.18 26,755 53,052 32,442 1,126 1,126 51,925 1.19 285.03 11 55 0.92 6.7 1.26 0.31 1.07 0.96 13.76 4,127 56,052 32,743 1,137 1,137 54,915 1.26 285.12 12 60 1.00 3.8 0.72 0.31 0.61 0.41 5.89 1,766 56,682 32,806 1,139 1,139 55,542 1.28 285.14 TOTAL RAINFALL 1.57 in RAINFALL VOLUME 81,396 cu-ft SOIL LOSSES 15,921 cu-ft EFFECTIVE RAIN 1.26 in FLOOD VOLUME 1.50 acft FLOOD VOLUME 65,475 cu-ft REQUIRED STORAGE 1.28 REQUIRED STORAGE 55,542 cu-ft MAX WSEL 285.14 ft PEAK FLOW RATE 89.18 cfs TOTAL BASIN LOSSES 9,932 cu-ft AVERAGE PERCOLATION RATE 165.53 cf/min EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Total In Basin in/hr Time Loss Rate Basin Losses Del Webb Explore at Palm DesertRCFC & WCD HYDROLOGY MANUAL SYNTHETIC UNIT HYDROGRAPH METHOD SHORTCUT METHOD 1-HOUR STORM Plate E-2.2 1-Hour Storm Page 4 of 13 PROJECT: Job No.:2636 BY:RJB DATE DRAINAGE AREA-ACRES 14.28 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 2.62 Maxwell Drywells UNIT TIME-PERCENT OF LAG 190.8 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.27 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.31 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 5 0.08 1.3 0.35 0.31 0.30 0.05 0.68 203 203 13,005 452 203 0 0.00 283.00 2 10 0.17 1.3 0.35 0.31 0.30 0.05 0.68 203 203 13,005 452 203 0 0.00 283.00 3 15 0.25 1.1 0.30 0.31 0.25 0.04 0.65 194 194 12,998 451 194 0 0.00 283.00 4 20 0.33 1.5 0.41 0.31 0.35 0.10 1.46 439 439 13,191 458 439 0 0.00 283.00 5 25 0.42 1.5 0.41 0.31 0.35 0.10 1.46 439 439 13,191 458 439 0 0.00 283.00 6 30 0.50 1.8 0.49 0.31 0.42 0.18 2.64 792 792 13,470 468 468 324 0.01 283.02 7 35 0.58 1.5 0.41 0.31 0.35 0.10 1.46 439 762 13,447 467 467 295 0.01 283.01 8 40 0.67 1.8 0.49 0.31 0.42 0.18 2.64 792 1,087 13,704 476 476 611 0.01 283.03 9 45 0.75 1.8 0.49 0.31 0.42 0.18 2.64 792 1,403 13,954 485 485 918 0.02 283.05 10 50 0.83 1.5 0.41 0.31 0.35 0.10 1.46 439 1,357 13,917 483 483 874 0.02 283.04 11 55 0.92 1.6 0.44 0.31 0.37 0.13 1.85 556 1,430 13,975 485 485 945 0.02 283.05 12 60 1.00 1.8 0.49 0.31 0.42 0.18 2.64 792 1,736 14,217 494 494 1,242 0.03 283.06 13 65 1.08 2.2 0.60 0.31 0.51 0.29 4.21 1,262 2,505 14,826 515 515 1,990 0.05 283.10 14 70 1.17 2.2 0.60 0.31 0.51 0.29 4.21 1,262 3,252 15,417 535 535 2,717 0.06 283.13 15 75 1.25 2.2 0.60 0.31 0.51 0.29 4.21 1,262 3,979 15,992 555 555 3,424 0.08 283.17 16 80 1.33 2.0 0.54 0.31 0.46 0.24 3.42 1,027 4,451 16,365 568 568 3,883 0.09 283.19 17 85 1.42 2.6 0.71 0.31 0.60 0.40 5.78 1,733 5,616 17,287 600 600 5,016 0.12 283.25 18 90 1.50 2.7 0.74 0.31 0.63 0.43 6.17 1,851 6,866 18,276 635 635 6,232 0.14 283.31 19 95 1.58 2.4 0.65 0.31 0.56 0.35 4.99 1,498 7,729 18,959 658 658 7,071 0.16 283.35 20 100 1.67 2.7 0.74 0.31 0.63 0.43 6.17 1,851 8,922 19,902 691 691 8,231 0.19 283.40 21 105 1.75 3.3 0.90 0.31 0.76 0.59 8.52 2,557 10,788 21,379 742 742 10,045 0.23 283.49 22 110 1.83 3.1 0.84 0.31 0.72 0.54 7.74 2,322 12,367 22,628 786 786 11,581 0.27 283.57 23 115 1.92 2.9 0.79 0.31 0.67 0.48 6.95 2,086 13,667 23,657 821 821 12,846 0.29 283.63 24 120 2.00 3.0 0.82 0.31 0.69 0.51 7.35 2,204 15,050 24,750 859 859 14,190 0.33 283.70 25 125 2.08 3.1 0.84 0.31 0.72 0.54 7.74 2,322 16,512 25,907 900 900 15,612 0.36 283.77 RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 3-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Loss Rate Basin Losses Plate E-2.2 3-Hour Storm Page 5 of 13 PROJECT: Job No.:2636 BY:RJB DATE DRAINAGE AREA-ACRES 14.28 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 2.62 Maxwell Drywells UNIT TIME-PERCENT OF LAG 190.8 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.27 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.31 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 3-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Loss Rate Basin Losses 26 130 2.17 4.2 1.14 0.31 0.97 0.84 12.05 3,616 19,228 28,056 974 974 18,254 0.42 283.90 27 135 2.25 5.0 1.36 0.31 1.16 1.05 15.19 4,558 22,812 29,214 1,014 1,014 21,798 0.50 284.05 28 140 2.33 3.5 0.95 0.31 0.81 0.65 9.31 2,792 24,590 29,405 1,021 1,021 23,569 0.54 284.10 29 145 2.42 6.8 1.85 0.31 1.57 1.55 22.25 6,676 30,245 30,011 1,042 1,042 29,203 0.67 284.29 30 150 2.50 7.3 1.99 0.31 1.69 1.68 24.21 7,264 36,467 30,678 1,065 1,065 35,402 0.81 284.49 31 155 2.58 8.2 2.23 0.31 1.90 1.93 27.75 8,324 43,725 31,457 1,092 1,092 42,633 0.98 284.73 32 160 2.67 5.9 1.61 0.31 1.37 1.30 18.72 5,617 48,250 31,942 1,109 1,109 47,141 1.08 284.88 33 165 2.75 2.0 0.54 0.31 0.46 0.24 3.42 1,027 48,168 31,933 1,109 1,109 47,059 1.08 284.87 34 170 2.83 1.8 0.49 0.31 0.42 0.18 2.64 792 47,851 31,899 1,108 1,108 46,743 1.07 284.86 35 175 2.92 1.8 0.49 0.31 0.42 0.18 2.64 792 47,535 31,865 1,106 1,106 46,428 1.07 284.85 36 180 3.00 0.6 0.16 0.31 0.14 0.02 0.35 106 46,534 31,758 1,103 1,103 45,431 1.04 284.82 TOTAL RAIN RAINFALL VOLUME SOIL LOSSES EFFECTIVE RAIN FLOOD VOLUME FLOOD VOLUME REQUIRED STORAGE REQUIRED STORAGE MAX WSEL PEAK FLOW RATE TOTAL BASIN LOSSES AVERAGE PERCOLATION RATE EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY 25,445 cu-ft 141.36 cf/min 1.37 in 1.63 acft 70,876 cu-ft 1.08 acft 47,141 cu-ft 46,811 cu-ft 2.27 in 117,687 cu-ft 284.88 ft 27.75 cfs Plate E-2.2 3-Hour Storm Page 6 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 14.28 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 2.62 Maxwell Drywells UNIT TIME-PERCENT OF LAG 190.8 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.98 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.31 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 5 0.08 0.5 0.18 0.31 0.15 0.03 0.39 116 116 12,936 449 116 0 0.00 283.00 2 10 0.17 0.6 0.21 0.31 0.18 0.03 0.46 139 139 12,954 450 139 0 0.00 283.00 3 15 0.25 0.6 0.21 0.31 0.18 0.03 0.46 139 139 12,954 450 139 0 0.00 283.00 4 20 0.33 0.6 0.21 0.31 0.18 0.03 0.46 139 139 12,954 450 139 0 0.00 283.00 5 25 0.42 0.6 0.21 0.31 0.18 0.03 0.46 139 139 12,954 450 139 0 0.00 283.00 6 30 0.50 0.7 0.25 0.31 0.21 0.04 0.54 162 162 12,972 450 162 0 0.00 283.00 7 35 0.58 0.7 0.25 0.31 0.21 0.04 0.54 162 162 12,972 450 162 0 0.00 283.00 8 40 0.67 0.7 0.25 0.31 0.21 0.04 0.54 162 162 12,972 450 162 0 0.00 283.00 9 45 0.75 0.7 0.25 0.31 0.21 0.04 0.54 162 162 12,972 450 162 0 0.00 283.00 10 50 0.83 0.7 0.25 0.31 0.21 0.04 0.54 162 162 12,972 450 162 0 0.00 283.00 11 55 0.92 0.7 0.25 0.31 0.21 0.04 0.54 162 162 12,972 450 162 0 0.00 283.00 12 60 1.00 0.8 0.29 0.31 0.24 0.04 0.62 185 185 12,991 451 185 0 0.00 283.00 13 65 1.08 0.8 0.29 0.31 0.24 0.04 0.62 185 185 12,991 451 185 0 0.00 283.00 14 70 1.17 0.8 0.29 0.31 0.24 0.04 0.62 185 185 12,991 451 185 0 0.00 283.00 15 75 1.25 0.8 0.29 0.31 0.24 0.04 0.62 185 185 12,991 451 185 0 0.00 283.00 16 80 1.33 0.8 0.29 0.31 0.24 0.04 0.62 185 185 12,991 451 185 0 0.00 283.00 17 85 1.42 0.8 0.29 0.31 0.24 0.04 0.62 185 185 12,991 451 185 0 0.00 283.00 18 90 1.50 0.8 0.29 0.31 0.24 0.04 0.62 185 185 12,991 451 185 0 0.00 283.00 19 95 1.58 0.8 0.29 0.31 0.24 0.04 0.62 185 185 12,991 451 185 0 0.00 283.00 20 100 1.67 0.8 0.29 0.31 0.24 0.04 0.62 185 185 12,991 451 185 0 0.00 283.00 21 105 1.75 0.8 0.29 0.31 0.24 0.04 0.62 185 185 12,991 451 185 0 0.00 283.00 22 110 1.83 0.8 0.29 0.31 0.24 0.04 0.62 185 185 12,991 451 185 0 0.00 283.00 23 115 1.92 0.8 0.29 0.31 0.24 0.04 0.62 185 185 12,991 451 185 0 0.00 283.00 24 120 2.00 0.9 0.32 0.31 0.27 0.01 0.21 64 64 12,894 448 64 0 0.00 283.00 Loss Rate RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 6-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Basin Losses Plate E-2.2 6-Hour Storm Page 7 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 14.28 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 2.62 Maxwell Drywells UNIT TIME-PERCENT OF LAG 190.8 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.98 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.31 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft Loss Rate RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 6-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Basin Losses 25 125 2.08 0.8 0.29 0.31 0.24 0.04 0.62 185 185 12,991 451 185 0 0.00 283.00 26 130 2.17 0.9 0.32 0.31 0.27 0.01 0.21 64 64 12,894 448 64 0 0.00 283.00 27 135 2.25 0.9 0.32 0.31 0.27 0.01 0.21 64 64 12,894 448 64 0 0.00 283.00 28 140 2.33 0.9 0.32 0.31 0.27 0.01 0.21 64 64 12,894 448 64 0 0.00 283.00 29 145 2.42 0.9 0.32 0.31 0.27 0.01 0.21 64 64 12,894 448 64 0 0.00 283.00 30 150 2.50 0.9 0.32 0.31 0.27 0.01 0.21 64 64 12,894 448 64 0 0.00 283.00 31 155 2.58 0.9 0.32 0.31 0.27 0.01 0.21 64 64 12,894 448 64 0 0.00 283.00 32 160 2.67 0.9 0.32 0.31 0.27 0.01 0.21 64 64 12,894 448 64 0 0.00 283.00 33 165 2.75 1.0 0.36 0.31 0.30 0.05 0.73 218 218 13,017 452 218 0 0.00 283.00 34 170 2.83 1.0 0.36 0.31 0.30 0.05 0.73 218 218 13,017 452 218 0 0.00 283.00 35 175 2.92 1.0 0.36 0.31 0.30 0.05 0.73 218 218 13,017 452 218 0 0.00 283.00 36 180 3.00 1.0 0.36 0.31 0.30 0.05 0.73 218 218 13,017 452 218 0 0.00 283.00 37 185 3.08 1.0 0.36 0.31 0.30 0.05 0.73 218 218 13,017 452 218 0 0.00 283.00 38 190 3.17 1.1 0.39 0.31 0.33 0.09 1.24 373 373 13,139 456 373 0 0.00 283.00 39 195 3.25 1.1 0.39 0.31 0.33 0.09 1.24 373 373 13,139 456 373 0 0.00 283.00 40 200 3.33 1.1 0.39 0.31 0.33 0.09 1.24 373 373 13,139 456 373 0 0.00 283.00 41 205 3.42 1.2 0.43 0.31 0.36 0.12 1.76 527 527 13,261 460 460 67 0.00 283.00 42 210 3.50 1.3 0.46 0.31 0.40 0.16 2.27 682 748 13,436 467 467 282 0.01 283.01 43 215 3.58 1.4 0.50 0.31 0.43 0.19 2.79 836 1,118 13,729 477 477 641 0.01 283.03 44 220 3.67 1.4 0.50 0.31 0.43 0.19 2.79 836 1,478 14,013 487 487 991 0.02 283.05 45 225 3.75 1.5 0.54 0.31 0.46 0.23 3.30 991 1,982 14,412 500 500 1,481 0.03 283.07 46 230 3.83 1.5 0.54 0.31 0.46 0.23 3.30 991 2,472 14,800 514 514 1,958 0.04 283.10 47 235 3.92 1.6 0.57 0.31 0.49 0.27 3.82 1,145 3,103 15,299 531 531 2,572 0.06 283.13 48 240 4.00 1.6 0.57 0.31 0.49 0.27 3.82 1,145 3,717 15,785 548 548 3,169 0.07 283.16 49 245 4.08 1.7 0.61 0.31 0.52 0.30 4.33 1,300 4,469 16,379 569 569 3,900 0.09 283.19 50 250 4.17 1.8 0.64 0.31 0.55 0.34 4.85 1,454 5,354 17,080 593 593 4,761 0.11 283.23 Plate E-2.2 6-Hour Storm Page 8 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 14.28 Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 5 LAG TIME - MINUTES 2.62 Maxwell Drywells UNIT TIME-PERCENT OF LAG 190.8 Number 0 TOTAL ADJUSTED STORM RAIN (in)2.98 Drywell Percolation Rate 0.00 cfs 0.00 cfm CONSTANT LOSS RATE (in/hr)0.31 LOW LOSS RATE - PERCENT 85.00% Unit Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft Loss Rate RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD Total In Basin in/hr MANUAL 6-HOUR STORM UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM Time Basin Losses 51 255 4.25 1.9 0.68 0.31 0.58 0.37 5.36 1,609 6,370 17,883 621 621 5,749 0.13 283.28 52 260 4.33 2.0 0.72 0.31 0.61 0.41 5.88 1,763 7,512 18,787 652 652 6,860 0.16 283.34 53 265 4.42 2.1 0.75 0.31 0.64 0.44 6.39 1,918 8,777 19,788 687 687 8,090 0.19 283.40 54 270 4.50 2.1 0.75 0.31 0.64 0.44 6.39 1,918 10,008 20,761 721 721 9,287 0.21 283.46 55 275 4.58 2.2 0.79 0.31 0.67 0.48 6.91 2,072 11,359 21,831 758 758 10,601 0.24 283.52 56 280 4.67 2.3 0.82 0.31 0.70 0.52 7.42 2,227 12,828 22,992 798 798 12,029 0.28 283.59 57 285 4.75 2.4 0.86 0.31 0.73 0.55 7.94 2,381 14,410 24,245 842 842 13,569 0.31 283.67 58 290 4.83 2.4 0.86 0.31 0.73 0.55 7.94 2,381 15,950 25,462 884 884 15,066 0.35 283.74 59 295 4.92 2.5 0.89 0.31 0.76 0.59 8.45 2,536 17,601 26,769 929 929 16,672 0.38 283.82 60 300 5.00 2.6 0.93 0.31 0.79 0.62 8.97 2,690 19,362 28,162 978 978 18,384 0.42 283.90 61 305 5.08 3.1 1.11 0.31 0.94 0.80 11.54 3,463 21,847 29,110 1,011 1,011 20,836 0.48 284.02 62 310 5.17 3.6 1.29 0.31 1.09 0.98 14.12 4,235 25,071 29,456 1,023 1,023 24,048 0.55 284.12 63 315 5.25 3.9 1.39 0.31 1.19 1.09 15.66 4,699 28,747 29,850 1,036 1,036 27,710 0.64 284.24 64 320 5.33 4.2 1.50 0.31 1.28 1.19 17.21 5,162 32,872 30,293 1,052 1,052 31,821 0.73 284.37 65 325 5.42 4.7 1.68 0.31 1.43 1.37 19.78 5,935 37,755 30,817 1,070 1,070 36,685 0.84 284.53 66 330 5.50 5.6 2.00 0.31 1.70 1.70 24.42 7,325 44,010 31,487 1,093 1,093 42,917 0.99 284.74 67 335 5.58 1.9 0.68 0.31 0.58 0.37 5.36 1,609 44,526 31,543 1,095 1,095 43,430 1.00 284.75 68 340 5.67 0.9 0.32 0.31 0.27 0.01 0.21 64 43,494 31,432 1,091 1,091 42,403 0.97 284.72 69 345 5.75 0.6 0.21 0.31 0.18 0.03 0.46 139 42,542 31,330 1,088 1,088 41,454 0.95 284.69 70 350 5.83 0.5 0.18 0.31 0.15 0.03 0.39 116 41,570 31,226 1,084 1,084 40,485 0.93 284.66 71 355 5.92 0.3 0.11 0.31 0.09 0.02 0.23 70 40,555 31,117 1,080 1,080 39,475 0.91 284.63 72 360 6.00 0.2 0.07 0.31 0.06 0.01 0.15 46 39,521 31,006 1,077 1,077 38,444 0.88 284.59 TOTAL RAINFALL RAINFALL VOLUME SOIL LOSSES EFFECTIVE RAIN FLOOD VOLUME FLOOD VOLUME REQUIRED STORAGE REQUIRED STORAGE MAX WSEL PEAK FLOW RATE TOTAL BASIN LOSSES AVERAGE PERCOLATION RATE EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY 90.53 cf/min 32,591 cu-ft 1.37 in 1.63 acft 71,036 cu-ft 1.00 acft 43,430 cu-ft 154,497 cu-ft 2.98 in 83,461 cu-ft 284.75 ft 24.42 cfs Plate E-2.2 6-Hour Storm Page 9 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 14.28 VARIABLE LOSS RATE (AVG) IN/HR Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 15 Fm = Minimum value on loss curve (in/hr)0.15 LAG TIME - MINUTES 2.62 C 0.00284 Maxwell Drywells UNIT TIME-PERCENT OF LAG 572%Low Loss Rate (percent)85.00%Number 0 TOTAL ADJUSTED STORM RAIN (in)4.59 Drywell Percolation Rate 0.00 cfs 0.00 cfm Unit Time Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft 1 15 0.25 0.2 0.037 0.542 0.031 0.01 0.08 71 71 12,900 1,344 71 0 0.00 283.00 2 30 0.50 0.3 0.055 0.536 0.047 0.01 0.12 107 107 12,929 1,347 107 0 0.00 283.00 3 45 0.75 0.3 0.055 0.530 0.047 0.01 0.12 107 107 12,929 1,347 107 0 0.00 283.00 4 60 1.00 0.4 0.073 0.524 0.062 0.01 0.16 143 143 12,957 1,350 143 0 0.00 283.00 5 75 1.25 0.3 0.055 0.517 0.047 0.01 0.12 107 107 12,929 1,347 107 0 0.00 283.00 6 90 1.50 0.3 0.055 0.511 0.047 0.01 0.12 107 107 12,929 1,347 107 0 0.00 283.00 7 105 1.75 0.3 0.055 0.505 0.047 0.01 0.12 107 107 12,929 1,347 107 0 0.00 283.00 8 120 2.00 0.4 0.073 0.499 0.062 0.01 0.16 143 143 12,957 1,350 143 0 0.00 283.00 9 135 2.25 0.4 0.073 0.493 0.062 0.01 0.16 143 143 12,957 1,350 143 0 0.00 283.00 10 150 2.50 0.4 0.073 0.487 0.062 0.01 0.16 143 143 12,957 1,350 143 0 0.00 283.00 11 165 2.75 0.5 0.092 0.481 0.078 0.01 0.20 178 178 12,985 1,353 178 0 0.00 283.00 12 180 3.00 0.5 0.092 0.475 0.078 0.01 0.20 178 178 12,985 1,353 178 0 0.00 283.00 13 195 3.25 0.5 0.092 0.469 0.078 0.01 0.20 178 178 12,985 1,353 178 0 0.00 283.00 14 210 3.50 0.5 0.092 0.463 0.078 0.01 0.20 178 178 12,985 1,353 178 0 0.00 283.00 15 225 3.75 0.5 0.092 0.458 0.078 0.01 0.20 178 178 12,985 1,353 178 0 0.00 283.00 16 240 4.00 0.6 0.110 0.452 0.094 0.02 0.24 214 214 13,013 1,356 214 0 0.00 283.00 17 255 4.25 0.6 0.110 0.446 0.094 0.02 0.24 214 214 13,013 1,356 214 0 0.00 283.00 18 270 4.50 0.7 0.129 0.440 0.109 0.02 0.28 250 250 13,042 1,359 250 0 0.00 283.00 19 285 4.75 0.7 0.129 0.435 0.109 0.02 0.28 250 250 13,042 1,359 250 0 0.00 283.00 20 300 5.00 0.8 0.147 0.429 0.125 0.02 0.32 286 286 13,070 1,361 286 0 0.00 283.00 21 315 5.25 0.6 0.110 0.424 0.094 0.02 0.24 214 214 13,013 1,356 214 0 0.00 283.00 22 330 5.50 0.7 0.129 0.418 0.109 0.02 0.28 250 250 13,042 1,359 250 0 0.00 283.00 23 345 5.75 0.8 0.147 0.413 0.125 0.02 0.32 286 286 13,070 1,361 286 0 0.00 283.00 24 360 6.00 0.8 0.147 0.407 0.125 0.02 0.32 286 286 13,070 1,361 286 0 0.00 283.00 25 375 6.25 0.9 0.165 0.402 0.140 0.02 0.36 321 321 13,098 1,364 321 0 0.00 283.00 26 390 6.50 0.9 0.165 0.396 0.140 0.02 0.36 321 321 13,098 1,364 321 0 0.00 283.00 27 405 6.75 1.0 0.184 0.391 0.156 0.03 0.40 357 357 13,126 1,367 357 0 0.00 283.00 28 420 7.00 1.0 0.184 0.386 0.156 0.03 0.40 357 357 13,126 1,367 357 0 0.00 283.00 29 435 7.25 1.0 0.184 0.381 0.156 0.03 0.40 357 357 13,126 1,367 357 0 0.00 283.00 30 450 7.50 1.1 0.202 0.375 0.172 0.03 0.44 393 393 13,155 1,370 393 0 0.00 283.00 31 465 7.75 1.2 0.220 0.370 0.187 0.03 0.48 428 428 13,183 1,373 428 0 0.00 283.00 32 480 8.00 1.3 0.239 0.365 0.203 0.04 0.52 464 464 13,211 1,376 464 0 0.00 283.00 33 495 8.25 1.5 0.275 0.360 0.234 0.04 0.59 535 535 13,268 1,382 535 0 0.00 283.00 34 510 8.50 1.5 0.275 0.355 0.234 0.04 0.59 535 535 13,268 1,382 535 0 0.00 283.00 35 525 8.75 1.6 0.294 0.350 0.250 0.04 0.63 571 571 13,296 1,385 571 0 0.00 283.00 36 540 9.00 1.7 0.312 0.345 0.265 0.05 0.67 607 607 13,324 1,388 607 0 0.00 283.00 37 555 9.25 1.9 0.349 0.340 0.297 0.01 0.12 111 111 12,932 1,347 111 0 0.00 283.00 38 570 9.50 2.0 0.367 0.335 0.312 0.03 0.46 412 412 13,170 1,372 412 0 0.00 283.00 39 585 9.75 2.1 0.386 0.331 0.328 0.05 0.79 712 712 13,407 1,397 712 0 0.00 283.00 40 600 10.00 2.2 0.404 0.326 0.343 0.08 1.12 1,012 1,012 13,644 1,421 1,012 0 0.00 283.00 41 615 10.25 1.5 0.275 0.321 0.234 0.04 0.59 535 535 13,268 1,382 535 0 0.00 283.00 42 630 10.50 1.5 0.275 0.317 0.234 0.04 0.59 535 535 13,268 1,382 535 0 0.00 283.00 43 645 10.75 2.0 0.367 0.312 0.312 0.06 0.80 717 717 13,411 1,397 717 0 0.00 283.00 in/hr Total In Basin UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Loss Rate Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD MANUAL 24-HOUR STORM Basin Losses Plate E-2.2 24-Hour Storm Page 10 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 14.28 VARIABLE LOSS RATE (AVG) IN/HR Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 15 Fm = Minimum value on loss curve (in/hr)0.15 LAG TIME - MINUTES 2.62 C 0.00284 Maxwell Drywells UNIT TIME-PERCENT OF LAG 572%Low Loss Rate (percent)85.00%Number 0 TOTAL ADJUSTED STORM RAIN (in)4.59 Drywell Percolation Rate 0.00 cfs 0.00 cfm Unit Time Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft in/hr Total In Basin UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Loss Rate Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD MANUAL 24-HOUR STORM Basin Losses 44 660 11.00 2.0 0.367 0.307 0.312 0.06 0.86 776 776 13,458 1,402 776 0 0.00 283.00 45 675 11.25 1.9 0.349 0.303 0.297 0.05 0.66 597 597 13,316 1,387 597 0 0.00 283.00 46 690 11.50 1.9 0.349 0.298 0.297 0.05 0.73 654 654 13,362 1,392 654 0 0.00 283.00 47 705 11.75 1.7 0.312 0.294 0.265 0.02 0.26 236 236 13,031 1,357 236 0 0.00 283.00 48 720 12.00 1.8 0.330 0.290 0.281 0.04 0.59 530 530 13,264 1,382 530 0 0.00 283.00 49 735 12.25 2.5 0.459 0.285 0.390 0.17 2.50 2,252 2,252 14,626 1,524 1,524 729 0.02 283.04 50 750 12.50 2.6 0.477 0.281 0.406 0.20 2.83 2,546 3,274 15,434 1,608 1,608 1,666 0.04 283.08 51 765 12.75 2.8 0.514 0.277 0.437 0.24 3.42 3,076 4,743 16,596 1,729 1,729 3,014 0.07 283.15 52 780 13.00 2.9 0.532 0.273 0.453 0.26 3.74 3,368 6,382 17,893 1,864 1,864 4,518 0.10 283.22 53 795 13.25 3.4 0.624 0.268 0.531 0.36 5.12 4,611 9,130 20,067 2,090 2,090 7,039 0.16 283.35 54 810 13.50 3.4 0.624 0.264 0.531 0.36 5.18 4,664 11,704 22,103 2,302 2,302 9,401 0.22 283.46 55 825 13.75 2.3 0.422 0.260 0.359 0.16 2.33 2,099 11,500 21,942 2,286 2,286 9,214 0.21 283.45 56 840 14.00 2.3 0.422 0.256 0.359 0.17 2.39 2,150 11,364 21,834 2,274 2,274 9,090 0.21 283.45 57 855 14.25 2.7 0.496 0.252 0.421 0.24 3.50 3,152 12,242 22,529 2,347 2,347 9,895 0.23 283.49 58 870 14.50 2.6 0.477 0.249 0.406 0.23 3.29 2,964 12,860 23,018 2,398 2,398 10,462 0.24 283.51 59 885 14.75 2.6 0.477 0.245 0.406 0.23 3.35 3,014 13,476 23,505 2,448 2,448 11,027 0.25 283.54 60 900 15.00 2.5 0.459 0.241 0.390 0.22 3.14 2,824 13,852 23,803 2,479 2,479 11,372 0.26 283.56 61 915 15.25 2.4 0.441 0.237 0.375 0.20 2.93 2,634 14,007 23,925 2,492 2,492 11,514 0.26 283.57 62 930 15.50 2.3 0.422 0.234 0.359 0.19 2.71 2,443 13,958 23,886 2,488 2,488 11,470 0.26 283.56 63 945 15.75 1.9 0.349 0.230 0.297 0.12 1.71 1,538 13,007 23,134 2,410 2,410 10,597 0.24 283.52 64 960 16.00 1.9 0.349 0.227 0.297 0.12 1.76 1,583 12,181 22,481 2,342 2,342 9,839 0.23 283.48 65 975 16.25 0.4 0.073 0.223 0.062 0.01 0.16 143 9,982 20,741 2,161 2,161 7,821 0.18 283.38 66 990 16.50 0.4 0.073 0.220 0.062 0.01 0.16 143 7,964 19,145 1,994 1,994 5,970 0.14 283.29 67 1005 16.75 0.3 0.055 0.216 0.047 0.01 0.12 107 6,077 17,652 1,839 1,839 4,238 0.10 283.21 68 1020 17.00 0.3 0.055 0.213 0.047 0.01 0.12 107 4,345 16,282 1,696 1,696 2,649 0.06 283.13 69 1035 17.25 0.5 0.092 0.210 0.078 0.01 0.20 178 2,828 15,081 1,571 1,571 1,257 0.03 283.06 70 1050 17.50 0.5 0.092 0.207 0.078 0.01 0.20 178 1,435 13,980 1,456 1,435 0 0.00 283.00 71 1065 17.75 0.5 0.092 0.204 0.078 0.01 0.20 178 178 12,985 1,353 178 0 0.00 283.00 72 1080 18.00 0.4 0.073 0.201 0.062 0.01 0.16 143 143 12,957 1,350 143 0 0.00 283.00 73 1095 18.25 0.4 0.073 0.198 0.062 0.01 0.16 143 143 12,957 1,350 143 0 0.00 283.00 74 1110 18.50 0.4 0.073 0.195 0.062 0.01 0.16 143 143 12,957 1,350 143 0 0.00 283.00 75 1125 18.75 0.3 0.055 0.192 0.047 0.01 0.12 107 107 12,929 1,347 107 0 0.00 283.00 76 1140 19.00 0.2 0.037 0.189 0.031 0.01 0.08 71 71 12,900 1,344 71 0 0.00 283.00 77 1155 19.25 0.3 0.055 0.187 0.047 0.01 0.12 107 107 12,929 1,347 107 0 0.00 283.00 78 1170 19.50 0.4 0.073 0.184 0.062 0.01 0.16 143 143 12,957 1,350 143 0 0.00 283.00 79 1185 19.75 0.3 0.055 0.182 0.047 0.01 0.12 107 107 12,929 1,347 107 0 0.00 283.00 80 1200 20.00 0.2 0.037 0.179 0.031 0.01 0.08 71 71 12,900 1,344 71 0 0.00 283.00 81 1215 20.25 0.3 0.055 0.177 0.047 0.01 0.12 107 107 12,929 1,347 107 0 0.00 283.00 82 1230 20.50 0.3 0.055 0.174 0.047 0.01 0.12 107 107 12,929 1,347 107 0 0.00 283.00 83 1245 20.75 0.3 0.055 0.172 0.047 0.01 0.12 107 107 12,929 1,347 107 0 0.00 283.00 84 1260 21.00 0.2 0.037 0.170 0.031 0.01 0.08 71 71 12,900 1,344 71 0 0.00 283.00 85 1275 21.25 0.3 0.055 0.168 0.047 0.01 0.12 107 107 12,929 1,347 107 0 0.00 283.00 86 1290 21.50 0.2 0.037 0.166 0.031 0.01 0.08 71 71 12,900 1,344 71 0 0.00 283.00 Plate E-2.2 24-Hour Storm Page 11 of 13 PROJECT: Job No.:2636 BY:RJB DATE 1/9/24 DRAINAGE AREA-ACRES 14.28 VARIABLE LOSS RATE (AVG) IN/HR Basin Percolation Rate 5.0 in/hr UNIT TIME-MINUTES 15 Fm = Minimum value on loss curve (in/hr)0.15 LAG TIME - MINUTES 2.62 C 0.00284 Maxwell Drywells UNIT TIME-PERCENT OF LAG 572%Low Loss Rate (percent)85.00%Number 0 TOTAL ADJUSTED STORM RAIN (in)4.59 Drywell Percolation Rate 0.00 cfs 0.00 cfm Unit Time Time Pattern Storm Effective Flood Volume Basin Basin Period Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSEL in/hr Flow Area Percolation Out (Plate E-5.9)Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft in/hr Total In Basin UNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORM RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD Loss Rate Del Webb Explore at Palm Desert HYDROLOGY SHORTCUT METHOD MANUAL 24-HOUR STORM Basin Losses 87 1305 21.75 0.3 0.055 0.164 0.047 0.01 0.12 107 107 12,929 1,347 107 0 0.00 283.00 88 1320 22.00 0.2 0.037 0.163 0.031 0.01 0.08 71 71 12,900 1,344 71 0 0.00 283.00 89 1335 22.25 0.3 0.055 0.161 0.047 0.01 0.12 107 107 12,929 1,347 107 0 0.00 283.00 90 1350 22.50 0.2 0.037 0.160 0.031 0.01 0.08 71 71 12,900 1,344 71 0 0.00 283.00 91 1365 22.75 0.2 0.037 0.158 0.031 0.01 0.08 71 71 12,900 1,344 71 0 0.00 283.00 92 1380 23.00 0.2 0.037 0.157 0.031 0.01 0.08 71 71 12,900 1,344 71 0 0.00 283.00 93 1395 23.25 0.2 0.037 0.156 0.031 0.01 0.08 71 71 12,900 1,344 71 0 0.00 283.00 94 1410 23.50 0.2 0.037 0.155 0.031 0.01 0.08 71 71 12,900 1,344 71 0 0.00 283.00 95 1425 23.75 0.2 0.037 0.154 0.031 0.01 0.08 71 71 12,900 1,344 71 0 0.00 283.00 96 1440 24.00 0.2 0.037 0.154 0.031 0.01 0.08 71 71 12,900 1,344 71 0 0.00 283.00 EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY TOTAL RAINFALL RAINFALL VOLUME SOIL LOSSES EFFECTIVE RAIN FLOOD VOLUME FLOOD VOLUME REQUIRED STORAGE REQUIRED STORAGE MAX WSEL PEAK FLOW RATE TOTAL BASIN LOSSES AVERAGE PERCOLATION RATE 64,740 cu-ft 44.96 cf/min 1.25 in 1.49 acft 64,740 cu-ft 0.26 acft 11,514 cu-ft 4.59 in 237,967 cu-ft 173,226 cu-ft 283.57 ft 5.18 cfs Plate E-2.2 24-Hour Storm Page 12 of 13 PROECT JOB No. BASIN DESIGNATION: BASIN CHARACTERISTICS CONTOUR ELEVATION INCR TOTAL INCR TOTAL INCR (ft)(ft)(sf)(sf)(cuft)(cuft)(acre-ft) 283 0 0 12,844 0 0 0.00 284 1 1 16,107 28,951 20,359 20,359 0.47 285 1 2 3,279 32,230 30,576 50,935 1.17 286 1 3 3,401 35,631 33,916 84,852 1.95 287 1 4 3,525 39,156 37,380 122,231 2.81 288 1 5 3,638 42,794 40,962 163,193 3.75 WHERE: TOTAL Retention Basin - J BASIN VOLUME WORKSHEET DEPTH AREA VOLUME Del Webb Explore at Palm Desert 2636 ()()2121213 1 AAAAEEV++−= Basin Volume Worksheet Page 13 of 13 Tract No. 38434 / Explore Palm Desert Mass/Rough Grading Hydrology Report Appendix H Riverside County Whitewater River Region WQMP Worksheets ATRIB = 3.913 acres Determine the Impervious Area Within ATRIB (AIMP)AIMP = 2.125 acres Calculate the Impervious Area Ratio (IF) IF = AIMP/ATRIB IF = 0.54 Use the following equation based on the WEF/ASCE Method CBMP = 0.858If 3 - 0.78If 2 + 0.774If + 0.04 CBMP = 0.37 Calculate VU, the 80% Unit Storage Volume VU = 0.40 x CBMP VU = 0.15 (in*ac)/ac Calculate the design storage volume of the BMP, VBMP VBMP (ft3) =VBMP = 2,089 ft3 QBMP = CBMP x I x ATRIB QBMP = 0.29 ft3/s I = Design Rainfall Intensity, 0.2 in/hr Notes: BMP Design Flow Rate, QBMP Company Name Designed By Company Project Number/Name Drainage Area Number/Name 2636 / DEL WEBB EXPLORE DA-A January 9, 2024 VU (in-ac/ac) x AT (ac) x 43,560 (ft2/ac) 12(in/ft) Calculate the Composite Runoff Coefficient, C for the BMP Tributary Area Determine Design Storage Volume, VBMP Legend: Required Entries Calculated Cells Determine the Impervious Area Ratio Whitewater Watershed BMP Design Volume, VBMP & Design Flow Rate , QBMP (Rev. 06-2014) Enter the Area Tributary to this Feature (ATRIB) MSA Consulting, Inc FOS Date County/City Case No. ATRIB = 4.664 acres Determine the Impervious Area Within ATRIB (AIMP)AIMP = 2.741 acres Calculate the Impervious Area Ratio (IF) IF = AIMP/ATRIB IF = 0.59 Use the following equation based on the WEF/ASCE Method CBMP = 0.858If 3 - 0.78If 2 + 0.774If + 0.04 CBMP = 0.40 Calculate VU, the 80% Unit Storage Volume VU = 0.40 x CBMP VU = 0.16 (in*ac)/ac Calculate the design storage volume of the BMP, VBMP VBMP (ft3) =VBMP = 2,706 ft3 QBMP = CBMP x I x ATRIB QBMP = 0.37 ft3/s I = Design Rainfall Intensity, 0.2 in/hr Notes: BMP Design Flow Rate, QBMP Company Name Designed By Company Project Number/Name Drainage Area Number/Name 2636 / DEL WEBB EXPLORE DA-B January 9, 2024 VU (in-ac/ac) x AT (ac) x 43,560 (ft2/ac) 12(in/ft) Calculate the Composite Runoff Coefficient, C for the BMP Tributary Area Determine Design Storage Volume, VBMP Legend: Required Entries Calculated Cells Determine the Impervious Area Ratio Whitewater Watershed BMP Design Volume, VBMP & Design Flow Rate , QBMP (Rev. 06-2014) Enter the Area Tributary to this Feature (ATRIB) MSA Consulting, Inc FOS Date County/City Case No. ATRIB = 4.014 acres Determine the Impervious Area Within ATRIB (AIMP)AIMP = 2.375 acres Calculate the Impervious Area Ratio (IF) IF = AIMP/ATRIB IF = 0.59 Use the following equation based on the WEF/ASCE Method CBMP = 0.858If 3 - 0.78If 2 + 0.774If + 0.04 CBMP = 0.40 Calculate VU, the 80% Unit Storage Volume VU = 0.40 x CBMP VU = 0.16 (in*ac)/ac Calculate the design storage volume of the BMP, VBMP VBMP (ft3) =VBMP = 2,347 ft3 QBMP = CBMP x I x ATRIB QBMP = 0.32 ft3/s I = Design Rainfall Intensity, 0.2 in/hr Legend: Required Entries Calculated Cells Determine the Impervious Area Ratio Whitewater Watershed BMP Design Volume, VBMP & Design Flow Rate , QBMP (Rev. 06-2014) Enter the Area Tributary to this Feature (ATRIB) MSA Consulting, Inc FOS Date County/City Case No. Notes: BMP Design Flow Rate, QBMP Company Name Designed By Company Project Number/Name Drainage Area Number/Name 2636 / DEL WEBB EXPLORE DA-C January 9, 2024 VU (in-ac/ac) x AT (ac) x 43,560 (ft2/ac) 12(in/ft) Calculate the Composite Runoff Coefficient, C for the BMP Tributary Area Determine Design Storage Volume, VBMP ATRIB = 4.345 acres Determine the Impervious Area Within ATRIB (AIMP)AIMP = 2.546 acres Calculate the Impervious Area Ratio (IF) IF = AIMP/ATRIB IF = 0.59 Use the following equation based on the WEF/ASCE Method CBMP = 0.858If 3 - 0.78If 2 + 0.774If + 0.04 CBMP = 0.40 Calculate VU, the 80% Unit Storage Volume VU = 0.40 x CBMP VU = 0.16 (in*ac)/ac Calculate the design storage volume of the BMP, VBMP VBMP (ft3) =VBMP = 2,513 ft3 QBMP = CBMP x I x ATRIB QBMP = 0.35 ft3/s I = Design Rainfall Intensity, 0.2 in/hr Legend: Required Entries Calculated Cells Determine the Impervious Area Ratio Whitewater Watershed BMP Design Volume, VBMP & Design Flow Rate , QBMP (Rev. 06-2014) Enter the Area Tributary to this Feature (ATRIB) MSA Consulting, Inc FOS Date County/City Case No. Notes: BMP Design Flow Rate, QBMP Company Name Designed By Company Project Number/Name Drainage Area Number/Name 2636 / DEL WEBB EXPLORE DA-D January 9, 2024 VU (in-ac/ac) x AT (ac) x 43,560 (ft2/ac) 12(in/ft) Calculate the Composite Runoff Coefficient, C for the BMP Tributary Area Determine Design Storage Volume, VBMP ATRIB = 10.593 acres Determine the Impervious Area Within ATRIB (AIMP)AIMP = 6.195 acres Calculate the Impervious Area Ratio (IF) IF = AIMP/ATRIB IF = 0.58 Use the following equation based on the WEF/ASCE Method CBMP = 0.858If 3 - 0.78If 2 + 0.774If + 0.04 CBMP = 0.40 Calculate VU, the 80% Unit Storage Volume VU = 0.40 x CBMP VU = 0.16 (in*ac)/ac Calculate the design storage volume of the BMP, VBMP VBMP (ft3) =VBMP = 6,113 ft3 QBMP = CBMP x I x ATRIB QBMP = 0.84 ft3/s I = Design Rainfall Intensity, 0.2 in/hr Notes: BMP Design Flow Rate, QBMP Company Name Designed By Company Project Number/Name Drainage Area Number/Name 2636 / DEL WEBB EXPLORE DA-E January 9, 2024 VU (in-ac/ac) x AT (ac) x 43,560 (ft2/ac) 12(in/ft) Calculate the Composite Runoff Coefficient, C for the BMP Tributary Area Determine Design Storage Volume, VBMP Legend: Required Entries Calculated Cells Determine the Impervious Area Ratio Whitewater Watershed BMP Design Volume, VBMP & Design Flow Rate , QBMP (Rev. 06-2014) Enter the Area Tributary to this Feature (ATRIB) MSA Consulting, Inc FOS Date County/City Case No. ATRIB = 3.843 acres Determine the Impervious Area Within ATRIB (AIMP)AIMP = 2.238 acres Calculate the Impervious Area Ratio (IF) IF = AIMP/ATRIB IF = 0.58 Use the following equation based on the WEF/ASCE Method CBMP = 0.858If 3 - 0.78If 2 + 0.774If + 0.04 CBMP = 0.40 Calculate VU, the 80% Unit Storage Volume VU = 0.40 x CBMP VU = 0.16 (in*ac)/ac Calculate the design storage volume of the BMP, VBMP VBMP (ft3) =VBMP = 2,207 ft3 QBMP = CBMP x I x ATRIB QBMP = 0.30 ft3/s I = Design Rainfall Intensity, 0.2 in/hr Legend: Required Entries Calculated Cells Determine the Impervious Area Ratio Whitewater Watershed BMP Design Volume, VBMP & Design Flow Rate , QBMP (Rev. 06-2014) Enter the Area Tributary to this Feature (ATRIB) MSA Consulting, Inc FOS Date County/City Case No. Notes: BMP Design Flow Rate, QBMP Company Name Designed By Company Project Number/Name Drainage Area Number/Name 2636 / DEL WEBB EXPLORE DA-F January 9, 2024 VU (in-ac/ac) x AT (ac) x 43,560 (ft2/ac) 12(in/ft) Calculate the Composite Runoff Coefficient, C for the BMP Tributary Area Determine Design Storage Volume, VBMP ATRIB = 44.360 acres Determine the Impervious Area Within ATRIB (AIMP)AIMP = 26.873 acres Calculate the Impervious Area Ratio (IF) IF = AIMP/ATRIB IF = 0.61 Use the following equation based on the WEF/ASCE Method CBMP = 0.858If 3 - 0.78If 2 + 0.774If + 0.04 CBMP = 0.41 Calculate VU, the 80% Unit Storage Volume VU = 0.40 x CBMP VU = 0.17 (in*ac)/ac Calculate the design storage volume of the BMP, VBMP VBMP (ft3) =VBMP = 26,627 ft3 QBMP = CBMP x I x ATRIB QBMP = 3.67 ft3/s I = Design Rainfall Intensity, 0.2 in/hr Legend: Required Entries Calculated Cells Determine the Impervious Area Ratio Whitewater Watershed BMP Design Volume, VBMP & Design Flow Rate , QBMP (Rev. 06-2014) Enter the Area Tributary to this Feature (ATRIB) MSA Consulting, Inc FOS Date County/City Case No. Notes: BMP Design Flow Rate, QBMP Company Name Designed By Company Project Number/Name Drainage Area Number/Name 2636 / DEL WEBB EXPLORE DA-G January 9, 2024 VU (in-ac/ac) x AT (ac) x 43,560 (ft2/ac) 12(in/ft) Calculate the Composite Runoff Coefficient, C for the BMP Tributary Area Determine Design Storage Volume, VBMP ATRIB = 2.463 acres Determine the Impervious Area Within ATRIB (AIMP)AIMP = 0.246 acres Calculate the Impervious Area Ratio (IF) IF = AIMP/ATRIB IF = 0.10 Use the following equation based on the WEF/ASCE Method CBMP = 0.858If 3 - 0.78If 2 + 0.774If + 0.04 CBMP = 0.11 Calculate VU, the 80% Unit Storage Volume VU = 0.40 x CBMP VU = 0.04 (in*ac)/ac Calculate the design storage volume of the BMP, VBMP VBMP (ft3) =VBMP = 395 ft3 QBMP = CBMP x I x ATRIB QBMP = 0.05 ft3/s I = Design Rainfall Intensity, 0.2 in/hr Legend: Required Entries Calculated Cells Determine the Impervious Area Ratio Whitewater Watershed BMP Design Volume, VBMP & Design Flow Rate , QBMP (Rev. 06-2014) Enter the Area Tributary to this Feature (ATRIB) MSA Consulting, Inc FOS Date County/City Case No. Notes: BMP Design Flow Rate, QBMP Company Name Designed By Company Project Number/Name Drainage Area Number/Name 2636 / DEL WEBB EXPLORE DA-H January 9, 2024 VU (in-ac/ac) x AT (ac) x 43,560 (ft2/ac) 12(in/ft) Calculate the Composite Runoff Coefficient, C for the BMP Tributary Area Determine Design Storage Volume, VBMP ATRIB = 1.332 acres Determine the Impervious Area Within ATRIB (AIMP)AIMP = 0.133 acres Calculate the Impervious Area Ratio (IF) IF = AIMP/ATRIB IF = 0.10 Use the following equation based on the WEF/ASCE Method CBMP = 0.858If 3 - 0.78If 2 + 0.774If + 0.04 CBMP = 0.11 Calculate VU, the 80% Unit Storage Volume VU = 0.40 x CBMP VU = 0.04 (in*ac)/ac Calculate the design storage volume of the BMP, VBMP VBMP (ft3) =VBMP = 214 ft3 QBMP = CBMP x I x ATRIB QBMP = 0.03 ft3/s I = Design Rainfall Intensity, 0.2 in/hr Legend: Required Entries Calculated Cells Determine the Impervious Area Ratio Whitewater Watershed BMP Design Volume, VBMP & Design Flow Rate , QBMP (Rev. 06-2014) Enter the Area Tributary to this Feature (ATRIB) MSA Consulting, Inc FOS Date County/City Case No. Notes: BMP Design Flow Rate, QBMP Company Name Designed By Company Project Number/Name Drainage Area Number/Name 2636 / DEL WEBB EXPLORE DA-I January 9, 2024 VU (in-ac/ac) x AT (ac) x 43,560 (ft2/ac) 12(in/ft) Calculate the Composite Runoff Coefficient, C for the BMP Tributary Area Determine Design Storage Volume, VBMP ATRIB = 14.282 acres Determine the Impervious Area Within ATRIB (AIMP)AIMP = 9.283 acres Calculate the Impervious Area Ratio (IF) IF = AIMP/ATRIB IF = 0.65 Use the following equation based on the WEF/ASCE Method CBMP = 0.858If 3 - 0.78If 2 + 0.774If + 0.04 CBMP = 0.45 Calculate VU, the 80% Unit Storage Volume VU = 0.40 x CBMP VU = 0.18 (in*ac)/ac Calculate the design storage volume of the BMP, VBMP VBMP (ft3) =VBMP = 9,315 ft3 QBMP = CBMP x I x ATRIB QBMP = 1.28 ft3/s I = Design Rainfall Intensity, 0.2 in/hr Notes: BMP Design Flow Rate, QBMP Company Name Designed By Company Project Number/Name Drainage Area Number/Name 2636 / DEL WEBB EXPLORE DA-J January 10, 2024 VU (in-ac/ac) x AT (ac) x 43,560 (ft2/ac) 12(in/ft) Calculate the Composite Runoff Coefficient, C for the BMP Tributary Area Determine Design Storage Volume, VBMP Legend: Required Entries Calculated Cells Determine the Impervious Area Ratio Whitewater Watershed BMP Design Volume, VBMP & Design Flow Rate , QBMP (Rev. 06-2014) Enter the Area Tributary to this Feature (ATRIB) MSA Consulting, Inc FOS Date County/City Case No. Tract No. 38434 / Explore Palm Desert Mass/Rough Grading Hydrology Report Appendix I Mass/Rough Grading Synthetic Unit Hydrograph (Shortcut Method) Hydrology Exhibit DA-B L=958' A=4.664DA-A L=755' A=3.193 DA-C L=800' A=4.014 DA-D L=862' A=4.345 DA-E L=803' A=10.593 NO PAR K I N G NO PAR K I N G NO PA R K I N G NOPARKING NO PA R K I N G C O M P A C T C A R C O M P A C T C A R C O M P A C T C A R C O M P A C T C A R C O M P A C T C A R C O M P A C T C A R C O M P A C T C A R COM P A C T CA R CO M P A C T CAR DA-F L=498' A=3.843 DA-G L=3515' A=44.359 DA-J L=1185' A=14.282DA-H L=1767' A=2.462 DA-I L=715' A=1.331 MSA CONSULTING, INC.> PLANNING > CIVIL ENGINEERING > LAND SURVEYING 34200 Bob Hope Drive, Rancho Mirage, CA 92270 760.320.9811 msaconsultinginc.com R: \ 2 6 3 6 \ A c a d \ H y d r o l o g y \ R O U G H G R A D I N G \ 2 6 3 6 R o u g h G r a d i n g S U H E x h i b i t S H T 0 1 . d w g , 1 / 9 / 2 0 2 4 3 : 4 7 : 1 2 P M , r b u t l e r , M S A C o n s u l t i n g , I n c . MSA CONSULTING, INC.> PLANNING > CIVIL ENGINEERING > LAND SURVEYING 34200 Bob Hope Drive, Rancho Mirage, CA 92270 760.320.9811 msaconsultinginc.com DRAINAGE AREA A DRAINAGE AREA B DRAINAGE AREA C DRAINAGE AREA D DRAINAGE AREA GDRAINAGE AREA F DRAINAGE AREA E DRAINAGE AREA JDRAINAGE AREA H DRAINAGE AREA I R: \ 2 6 3 6 \ A c a d \ H y d r o l o g y \ R O U G H G R A D I N G \ 2 6 3 6 R o u g h G r a d i n g S U H E x h i b i t S H T 0 2 . d w g , 1 / 9 / 2 0 2 4 3 : 4 8 : 1 9 P M , r b u t l e r , M S A C o n s u l t i n g , I n c .