2019-113 - Mainplace Mall Mixed-Use Project

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City of Santa Ana MainPlace Mall Transformation Project Water Supply Assessment 4.3 Water Rights/Groundwater Supply The City uses pumped groundwater from the OC Basin, which underlies the northern half of Orange County beneath broad lowlands. The OC Basin, managed by OCWD, covers an area of approximately 350 square miles, bordered by the Coyote and Chino Hills to the north, the Santa Ana Mountains to the northeast, and the Pacific Ocean to the southwest. The OC Basin boundary extends to the Orange County - Los Angeles line to the northwest, where groundwater flows across the county line into the Central Groundwater Basin of Los Angeles County. The OC Basin's full volume is approximately 66 million acre- feet. Santa Ana currently meets 71 percent of its water demand through groundwater from the OC Basin. The OC Basin is not adjudicated and as such, pumping from the OC Basin is managed through a process that uses financial incentives to encourage groundwater producers to pump a sustainable amount of water. The framework for the financial incentives is based on establishing the basin production percentage (BPP): the percentage of each Producer's total water supply that comes from groundwater pumped from the OC Basin. Groundwater production at or below the BPP is assessed a Replenishment Assessment. While there is no legal limit as to how much an agency pumps from the OC Basin, there is a financial disincentive to pump above the BPP. Agencies that pump above the BPP are charged the Replenishment Assessment plus the Basin Equity Assessment (BEA), which is calculated so that the cost of groundwater production is greater than MWD's full service rate. The BEA can be increased to discourage production above the BPP. The BPP is set uniformly for all Producers by OCWD on an annual basis. The BPP is set based on groundwater conditions, availability of imported water supplies, and OC Basin management objectives. The supplies available for recharge must be estimated for a given year. The supplies of recharge water that are estimated are: (1) Santa Ana River storm flow; (2) natural incidental recharge; (3) Santa Ana River baseflow, (4) groundwater replenishment system supplies; and, (5) other supplies such as imported waterand recycled water purchased forthe Alamitos Barrier. The BPP is a major factor in determining the cost of groundwater production from the OC Basin for that year. In some cases, OCWD encourages treating and pumping groundwater that does not meet drinking water standards in order to protect water quality. This is achieved by using a financial incentive called the BEA Exemption. A BEA Exemption is used to clean up and contain the spread of poor quality water. OCWD uses a partial or total exemption of the BEA to compensate a qualified participating agency or Producer for the costs of treating poor quality groundwater. When OCWD authorizes a BEA exemption for a project, it is obligated to provide the replenishment water for the production above the BPP and forgoes the BEA revenue that OCWD would otherwise receive from the producer. The BPP is the primary mechanism used by OCWD to manage pumping in the OC Basin. In 2013, OCWD's Board of Directors adopted a policy to establish a stable BPP with the intention to work toward achieving and maintaining a 75 percent BPP by Fiscal Year (FY) 2015-16. Although BPP is set at 75 percent, based on discussions with OCWD a conservative BPP of 70 percent is assumed through 2040. Principles of this policy include: ■ OCWD's goal is to achieve a stable 75 percent BPP, while maintaining the same process of setting the BPP on an annual basis, with the BPP set in April of each year after a public hearing has been Kimley)))Horn 55C-21 Page 113