14 ATTACHMENT 1 EXHIBIT A - Laserfiche WebLink

THE CITY OF Chapter 7.: , _, � .. Water Service Reliability and Drought Risk Assessment PL£ASANTON 7.1.1.1 Potable Water from Zone 7 One of them a in limitations of Zone 7's water system is the lack of interties. All of Zone 7's imported water supplies are conveyed through the Delta and the SBA; Arroyo Valle water is also conveyed through the SBA. Zone 7 has been working closely with DWR, VW, and ACWD to improve the reliability of the SBA. Between 2003 and 2012, DWR made improvements to the SBA within Zone 7's service area to increase capacity and improve reliability. The work included a new pump station (180 cubic feet per second (cfs)), inline reservoir (500 AF) and increased the canal carrying capacity to 380 cfs. As part of this project, Zone 7 had an emergency slide gate installed to maintain service in the event of a pipeline rupture downstream. Zone 7 will continue coordinating with DWR and South Bay Contractors to improve the reliability of the entire SBA system In addition, Zone 7 is pursuing the following projects to diversify its conveyance options: Reliability Intertie — Zone 7 is also planning for the construction of a reliability intertie with another major water agency that would provide an alternative means of conveying water to Zone 7's service area when the Delta and/or the SBA undergo an outage. For example, an intertie with EBMUD could convey treated water supply to the western portion of Zone 7's service area. • Chain of Lakes Pipeline — This pipeline would allow for access to water stored in the Chain of Lakes as an alternative local water supply; water would be accessible to the Del Valle Water Treatment Plant (WTP) via one of the SBA turnouts. Specific constraints for each of Zone 7's supplies are discussed below. 7.1.1.1.1 Imported Water: State Water Project Two key constraints on imported water from the SWP are Delta conveyance and water quality. Each constraint is detailed below. 7.1.1.1.1.1 Delta Conveyance Zone 7's long-term contract with DWR for SWP water provides Zone 7 access to Table A water (and Article 56c water or carryover), Article 21 water, Article 56d water, and Yuba Accord water. As an SWP contractor, Zone 7 is also able to use SWP facilities for conveying water transfers or exchanges of SWP water (from another contractor) or from another water agency outside of the SWP system. SWP water moves through the Delta before it is conveyed by the California Aqueduct and the SBA to Zone 7's water facilities. The instability of the aging levees in the Delta (including their vulnerability to seismic events and climate change), regulatory uncertainty, water quality issues including saltwater intrusion, and the declining health of the Delta ecosystem all challenge the long-term reliability of the SWP and, more generally, the water conveyance capability of the Delta. These issues directly challenge the Tri -Valley's long-term water supply reliability since a majority of Zone 7's water supply is and will continue to be tied to the Delta and SWP system. WEST YOST 7-2 City of Pleasanton 2020 Urban Water Management Plan May 2021