Item 21 - Water Supply Assessment for the Warner - Red Hill Mixed Use Development Project

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T HE W ARNER P ROJECT W ATER S UPPLY A SSESSMENT A UGUST 21, 2020 F USCOE E NGINEERING , I NC. 15 overdraft. DWR has one year to evaluate the Basin 8-1 Alterative. The paragraphs below will further explain how OCWD successfully manages the OC Basin to meet these new groundwater monitoring and management requirements. OCWD manages the Basin through the Basin Production Percentage (BPP) which is determined each water year. The BPP is set based on groundwater conditions, availability of imported water supplies, water year precipitation, SAR runoff, and basin management objectives. The BPP represents an established percentage identifying the amount of groundwater all pumpers in the Basin can pump without paying a “pumping tax” or Basin Equity Assessment (BEA) to OCWD. For example, if the BPP is set to 75%, all pumpers within the Basin, including the City, can supply 75% of their water needs from groundwater supplies at a cost significantly less than the cost of imported water. If groundwater production is equal to or less than the BPP (i.e. less than 75% in the example above), all producers within the Basin pay a replenishment assessment (RA) fee which is used to fund groundwater replenishment and recharge programs aimed at ensuring the long-term viability and stability of the Basin. If groundwater production is greater than the established BPP for that water year (i.e. greater than 75% in the example above), the BEA is determined for the producer of that amount of groundwater provided in excess of the BPP. The BEA is an additional fee paid on each AF of water pumped above the BPP, making the total cost of that additional water equal to the higher cost of imported water from Metropolitan. According to OCWD’s Engineer’s Report for fiscal year 2017/18, total water demands within the OCWD jurisdiction were 419,477 AF for the 2017-18 water year. Groundwater production totaled 310,025 AF with supplemental water totaling 227,413 AF. As shown in Table 6 below, the City utilized 35,054.1 AF of water in the 2017-18 water year. Table 6 City of Santa Ana Groundwater Production Data 2015-16 Groundwater Producer Groundwater Supplemental Water (AF) (AF) Actual BPP Total Deliveries Conservation Credit Total Grand Total Non-Irrigation Only City of Santa Ana 25,705.3 9,265.4 83.4 9,348.8 35,054.1 73.3% Source: OCWD 2017-18 Engineer’s Report Over the recent past, production capability of the Basin has increased as a result of increased wastewater reclamation at the Groundwater Replenishment System (GWRS) located in Fountain Valley. The GWRS, which is designed to turn wastewater into drinking water, is one of the most technologically advanced wastewater treatment plants in the world. A treatment plant expansion of 30 million gallons per day was recently put on line by OCWD increasing the recharge capacity of the GWRS to 100 million gallons per day. This equates to the recycling of over 110,000 AFY of wastewater back into the Basin for future extraction and potable use. A final expansion of the treatment system is being designed to have a capacity of 130 million gallons per day. Expansion projects to the GWRS increase local water supply reliability and ensure low- cost water supplies throughout northern Orange County, including the City of Santa Ana.