14 ATTACHMENT 1 EXHIBIT A - Laserfiche WebLink

This chapter describes the City's water service reliability under various hydrologic conditions, including a severe drought for the next five years. The City's existing and planned water management tools for increasing water supply reliability are also addressed. Responses to actual water shortage conditions are detailed in Chapter 8 of this plan. The reliability of the City's potable water supply is largely dependent upon its water supply from Zone 7 and Zone 7's water supply reliability policy. On October 17, 2012, the Zone 7 Board approved a revised Water Supply Reliability Policy (Resolution No. 13-4230, included as Appendix 1), which adopts the following level of service goals to guide the management of Zone 7's treated water (also referred to as municipal and industrial or (M&I) supplies and its Capital Improvement Program (CIP): Goal 1: Zone 7 will meet its treated water customers' water supply needs, in accordance with Zone 7's most current Contracts for M&I Water Supply, including existing and projected demands as specified in Zone 7's most recent UWMP, during normal, average, and drought conditions, as follows: At least 85 percent of M&I water demands 99 percent of the time 100 percent of M&I water demands 90 percent of the time Goal 2: Provide sufficient treated water production capacity and infrastructure to meet at least 80 percent of the maximum month M&I contractual demands should any one of Zone 7's major supply, production, or transmission facilities experience an extended unplanned outage of at least one week. 7.1 WATER SERVICE RELIABILITY ASSESSMENT Approximately 80 percent of the City's water is purchased from Zone 7, which is comprised of treated surface water blended with some local groundwater. The remaining 20 percent comes from local groundwater pumped from wells owned and operated by the City. As discussed in Chapter 6, the groundwater basin is managed by Zone 7, and the City has a GPQ. Additionally, the City receives recycled water from the DSRSD RWTF (through an agreement with DERWA) and the LWRP. As the City's exclusive potable water wholesaler, Zone 7's water supply reliability greatly affects the City's water supply reliability. Therefore, a significant portion of this section presents the constraints on Zone 7's existing and planned water sources and summarizes the historical basis for projecting available supplies in various hydrologic conditions (i.e., normal year, single dry year, and five consecutive dryyears). The City's water service reliability is then presented in five-year increments through 2045 based on earlier analysis of water use (Chapter 4 of this plan) and water supply (Chapter 6 of this plan). Finally, this section discusses the City's water management tools and options to promote regional supply reliability and minimize the need to import water from other regions. 7.1.1 Constraints on Water Sources This section discusses the constraints on Zone 7's water supply sources that affect their reliability and Zone 7's strategies for managing the risks associated with each supply. Constraints on groundwater and recycled water are also discussed. WEST YOST 7-1 City of Pleasanton 2020 Urban Water Management Plan May 2021