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City of Pleasanton 4.0 Water Agency Background Final Water Supply Assessment Stoneridge Drive Specific Plan Amendment and Staples Ranch Project demands would increase allowing more water to be used directly out of Lake Del Valle during rainy months rather than stored and then released for flood control needs." 5.3.4.3.3. Chain of Lakes Supplement to Lake Del Valle Zone 7, in conjunction with the local mining facilities, has formulated plans to reclaim many of the gravel quarries throughout the central portion of the Livermore-Amador Valley for use as groundwater recharge areas and surface water management facilities. The reclaimed quarries would forma "Chain of Lakes" that would allow Zone 7 to capture, store and use more local runoff. Water resource planning studies have shown that local runoff quantities would vary according to the hydrologic year and could reliably supply an additional 3,000 AFY in an average year. Two quarry pits have already been transferred to Zone 7. Completion of the "Chain of Lakes" is scheduled for 2030. 5.3.4.3.4. Recycled Water Currently, recycled water forms a small component of regional water supplies as it rounds out Zone 7's water portfolio. Tertiary treated wastewater supplied by the City of Livermore and Dublin San Ramon Services District is used for irrigation purposes within portions of Zone 7's service area. At present, almost 3,000 AF of irrigation demands are met with recycled water; 1,900 AFA is calculated into the 2007 Sustainable Water Supply Report. Recycled water is used at the City of Livermore's Municipal Golf Course, at Las Positas College and the business parks along the north side of I-580, at the Dublin City Sports Grounds, and at various other areas within the Livermore-Amador Valley. Staff at Zone 7 anticipates that as irrigation demands increase throughout the Tri-Valley area more recycled water can be used for those purposes. In 2030, roughly 6,000 AFA of tertiary treated reclaimed water would be available for irrigation uses. 5.3.4.4. Additional Zone 7 Supplies 5.3.4.4.5. Transfer Agreements and Opportunities In 1994, Zone 7 entered into ashort-term, 5-year water transfer project with Byron Bethany Irrigation District (BBID), which provided a minimum supplemental water supply of 2,000 AFA; the contract allows a potential 5,000 AFA to be purchased. In 1998, both parties agreed to 15-year contract, renewable every five years up to a total of 30 years. In 2006, Zone 7 purchased 1,000 AF. For conservative water supply planning purposes, Zone 7 uses the minimum 2,000 AFA. 5.3.4.5. Out-of-Basin Groundwater Banking Supplies 5.3.4.5.6. Semitropic Water Storage District Zone 7 purchased 22,000 AF of storage capacity in the Semitropic Water Storage District (STWSD) Groundwater Banking Program. Subsequently, an additional 43,000 AF of storage capacity for the Dougherty Valley development was acquired to increase reliability to these customers. In total, 65,000 AF of STWSD Out-of-Basin storage allows Zone 7 to bank SWP supplies during above average precipitation years. This STWSD water can be transferred back to Zone 7 via SWP conveyance facilities when the SWP pumping and conveyance facilities are operational. 5.4 Cawelo Water Storage District In 2004, Zone 7 entered into an "agreement in principle" bond and exchange program with Cawelo Water Storage District (CWSD) for an "In Lieu Banking Program". This involves transferring two acre-feet of surface water from Zone 7 into CWSD storage and taking out one acre-feet in drought 17 2005 Zone 7 Water Agency, Urban Water Management Plan, page 21. P:\Projecte - WP Only\41182.01 Staplea Ranch WSA\FinallFinal WSA.doc 5-15