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HomeMy WebLinkAboutNo 5 DSRT SURF Water Memo 111121r L J TERRA NOVA PLANNING & RESEARCH, INC.° MEMORANDUM November 11, 2021 TO: Eric Ceja FROM: Kelly Clark SUBJECT: DSRT SURF Water Demand Analysis A Water Supply Assessment (WSA) was prepared for the DSRT SURF project (Project) in 2019 that analyzed Project -specific water demands and potential impacts to the local and regional water supply. At that time, the Project included a 5.5-acre surf lagoon and associated amenities, up to 350 hotel rooms, up to 88 residential villas, and landscaping. The WSA determined that the 2019 Project would result in a gross water demand of 165.21 acre-feet per year (AFY) and a net water demand of 58.46 AFY after accounting for the turf reduction program which resulted in a savings of 106.75 AFY. For comparison, the net 2019 Project water demand of 58.46 AFY is less than the gross water demand for the 350 hotel rooms and 88 villas combined (60.99 AFY) (see below). The 2019 water demand breakdown is as follows: • Surf Lagoon; 73.04 AFY: Cloward H2O (2019) provided an annual water demand based on the following: o Volume: 6,900,000 gallons. Assumed a complete filling annually; Area: 236,720 SF (approx. 5.5 acres) o Water Loss: An average of 1,121 gallons/day from backwash and 45,177 gallons/day from evaporation, for a total of 46,298 gallons/day (16,898,770 gallons/year). • Evaporation was calculated using two methods: 1) 25+ year weather data for average monthly temperatures, humidity, wind, cloud cover and solar radiation rates; 2) published monthly pan evaporation rates for the area.' • Surf Lagoon Amenities; 15.28 AFY: Includes cafe, restaurant, bar, restrooms, maintenance. Standards water demand rates. • Hotel and Villas; 60.99 AFY: Includes 350 hotel rooms, 88 villas, hotel spa, villa clubhouse, and maintenance and equipment buildings. Standards water demand rates. • Swimming Pools; 7.36 AFY: Onsite pools/spas. Assumed one complete fill annually and total loss due to evaporation. • Landscaping; 8.54 AFY of Recycled Water: 120,159 square feet of landscaped area, including 11,795 square feet of turf and 108,364 square feet of native plant materials. CVWD MAWA calculation was used. • Turf Reduction Program for Firecliff and Mountain View Golf Courses: - 106.75 AFY. 'Water Supply Assessment and Water Supply Verification for the D5RT SURF Project, prepared by Terra Nova Planning and Research Inc. May 2019. 42635 MELANIE PLACE, SUITE 101, PALM DESERT, CA 92211 (760) 341-4800 The Project was amended in 2020 and resulted in a 27% reduction in commercial space, 71% reduction in restaurant/bar space, and 53% reduction is hotel and villa building square footage compared to maximum buildout assumptions analyzed in the 2019 EIR and WSA. The water demand for the 2020 project was analyzed using the assumptions shown below: • Surf Lagoon 73.04 AFY: Same assumptions used in the 2019 EIR/WSA. • Surf Lagoon Amenities; 2.62 AFY: Includes ancillary uses, maintenance, general retail. • Hotel and Villas; 22.79 AFY: Includes 92 hotel rooms and 83 villas. • Pools/Landscaping; 15.9 AFY: Same assumptions used in the 2019 EIR/WSA. • Turf Reduction Program;-106.75 AFY: Same assumptions used in the 2019 EIR/WSA. Buildout of the 2020 Project would result in a gross water demand of 114.35 AFY and a net water demand of 7.6 AFY, after accounting for the turf reduction program. For comparison, the net 2020 Project water demand of 7.6 AFY is equivalent to the annual water demands of 58 villas. The 2020 Project's water demand is detailed in the EIR Addendum prepared for the Project and submitted for review as part of the current entitlement package. Similar projects in the Valley, specifically the Wave at Coral Mountain in La Quinta (the Wave), used an oversimplified CVWD evaporation rate forthe wave pool based on a "Plant Factor of 1.10 for a stationary body of water, and 1.20 for a moving body of water:'z The analysis does not appear to account for annual loss due to backwash, spilling, or potential refilling of the wave pool. Compared to the La Quinta Wave project, DSRT SURF used conservative water demand estimates that assume the surf lagoon will require complete filling each year, accounts for water loss due to backwash and spilling, and uses historical weather data to account for monthly temperatures, humility, wind, cloud cover, and solar radiation that affect evaporation rates. 2 Coral Mountain Specific Plan WSA, prepared by MSA Consulting, Inc. March 2020.