55B - RESO - CIVIC CENTER WATER SUPPLY

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CITY OF SANTA ANA CIVIC CENTER FACILITIES STRATEGIC PLAN WATER SUPPLY ASSESSMENT The OC Basin's storage levels would be managed in accordance to the 75 percent BPP policy. It is presumed that the BPP will not decrease as long as the storage levels are between 100,000 and 300,000 AF from full capacity. If the OC Basin is less than 100,000 AF below full capacity, the BPP will be raised, If the OC Basin is over 350,000 AF below full capacity, additional supplies will be sought after to refill the OC Basin and the BPP will be lowered. The OC Basin is managed to maintain water storage levels of not more than 500,000 AF below full condition to avoid permanent and significant negative or adverse impacts. Operating the OC Basin in this manner enables OCWD to encourage reduced pumping during wet years when surface water supplies are plentiful and increase pumping during dry years to provide additional local water supplies during droughts, OCWD determines the optimum level of storage for the following year when it sets the BAP each year. Factors that affect this determination include the current storage level, regional water availability, and hydrologic conditions. When the OC Basin's storage approaches the lower end of the operating range, immediate issues that must be addressed include seawater intrusion, increased risk of land subsidence, and potential for shallow wells to become inoperable due to lower water levels. The OCWD's Engineer's Report reports on the groundwater conditions and investigates information related to water supply and OC Basin usage within OCWD's service area. The overall BPP achieved in the 2013 to 2014 water year within OCWD for non - irrigation use was 75.2 percent. However, a BPP level above 75 percent may be difficult to achieve. Therefore, a BPP ranging from 65 percent to 70 percent is currently being proposed for the ensuing FY 2015 -16, Analysis of the OC Basin's projected accumulated overdraft, the available supplies to the OC Basin (assuming average hydrology) and the projected pumping demands indicate that this level of pumping can be sustained for 2015 -I6 without harming the OC Basin. A BPP of 70 percent corresponds to approximately 320,000 AF of groundwater production including 22,000 AF of groundwater production above the BPP to account for several groundwater quality enhancement projects discussed earlier. In FY 2015 -16 additional production of approximately 22,000 AF above the BPP will be undertaken by the City of Tustin, City of Garden Grove, Mesa Water District, and Irvine Ranch Water District. These agencies use the additional pumping allowance in order to accommodate groundwater quality improvement projects. As in prior years, production above the BPP from these projects would be partially or fully exempt from the BEA as a result of the benefit provided to the OC Basin by removing poor - quality groundwater and treating it for beneficial use. Section 3.3.3 of the UWMP describes the Groundwater Recharge Facilities which are essential to support pumping from the OC Basin. Section 3.3.4 of the UWMP describes the Metropolitan Groundwater Replenishment Program to increase storage in the OC Basin. Section 3.3.5 of the UWMP describes the Metropolitan Conjunctive Use Program which allows for the storage of Metropolitan water in the OC Basin. Section 3.3.7 of the UWMP summarizes the annual analysis of basin storage change and accumulated overdraft for the recent years. 13 59B" 14