14 ATTACHMENT 1 EXHIBIT A - Laserfiche WebLink

THE CITY OF Chapter 7.: , _, � .. Water Service Reliability and Drought Risk Assessment PL£ASANTON 7.1.1.2 Groundwater Chapter 6 of this plan details the issues affecting the City and Zone 7's use of the Main Basin, specifically water quality management and prevention of overdraft. Zone 7 is actively implementing its Salt and Nutrient Management Plan. Salinity levels are being addressed primarily through groundwater pumping and demineralization using the MGDP in the Mocho wellfield. The facility simultaneously allows for the export of concentrated minerals or salts from the Main Basin while improving the water quality of treated water. Zone 7 has several groundwater wells with naturally -occurring Cr(VI) concentrations near the MCL and PFAS above the notification limit. In response, Zone 7 is actively managing flows from the affected wells. Conditions are regularly monitored, and management actions may change in the future. A PFAS treatment facility is under consideration for construction based on pending regulations. Zone 7 continues to study the groundwater basin and develop new tools (e.g., an improved groundwater model) to better understand the levels of groundwater extraction possible under various conditions while maintaining levels above the historical levels that have been reached in certain portions of the Main Basin ("historic lows"). Zone 7 also plans to augment its ability to recharge the Main Basin (e.g., through the Chain of Lakes) to increase local storage and allow for more pumping when necessary, which will improve both water supply reliability and salt management. Zone 7 plans to build an additional demineralization facility to continue to decrease the salt content of the Main Basin. Finally, Zone 7 plans to build additional wells to allow for improved management of groundwater levels and to increase groundwater production capacity during droughts and surface water -related outages. A new booster pump station will improve Zone 7's ability to convey groundwater throughout Zone 7's service area and increase production capacity. The City has a GPQ of 3,500 AFY from the Main Basin, which comprises approximately 20 percent of its water supply. The City may also carry over any unused portion of its annual GPQ up to a total of 700 AF. GPQ's for the Main Basin were determined based on the natural sustainable yield of the Main Basin. As such, the City's groundwater supply from its GPQ is considered reliable under all hydrologic conditions. 7.1.1.3 Recycled Water The recycled water that the City receives comes from DSRSD's RWTF and the LWRP, which are described in Section 6.2.5.2. Both facilities produce Title 22 disinfected tertiary recycled water. The City anticipates no significant changes to the land uses in either DSRSD's or Livermore's wastewater service area; therefore, it does not anticipate any changes to the quality of the wastewater effluent used to produce recycled water. The City does not expect recycled water quality issues to impact its ability to reliably deliver recycled water to its customers. On March 25, 2019, DERWA found that it cannot meet the combined peak demands and projected demands of its member agencies (DSRSD and EBMUD) and its retailer, the City. DERWA approved Resolution No. 19-3 (Appendix J) requesting that its member agencies take action to reduce recycled water demands and implement a connection moratorium. As discussed in Section 6.2.5.1.1, the City maintains the first right to use the secondary effluent produced from wastewater originating from the City's wastewater collection system for recycling. While the City's recycled water supply is limited by the secondary wastewater effluent from its service area, this supply is expected to meet the City's current and projected recycled water demands. WEST YOST 7-6 City of Pleasanton 2020 Urban Water Management Plan N-680-00-20-04-wP-a-680-2020uwMP May 2021