Item 07 - Response to OC Grand Jury Report_ Historic Rain, Yet Drought

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HISTORIC RAIN, YET DROUGHT REMAINS ORANGE COUNTY GRAND JURY 2022 I 2023 Page 41 of 57 In summary, water recycling is an important part of Orange County’s water supply and needs to be utilized to the maximum extent. However, it will not resolve water resiliency issues by itself and it relies on existing sources of water. Reuse of Water for Potable Purposes Reusing wastewater for potable purposes is an important part of North Orange County’s water portfolio. Orange County Water District produces 130 million gallons of indirect reuse water per day. However, the amount reused water is dependent upon the diminishing supplies within Orange County. Water reuse is used to enhance water security, sustainability, and resilience. The process of using treated wastewater for drinking water is called potable water reuse. Potable water reuse provides another option for expanding a region’s water supply portfolio. There are two types of potable water reuse: • Indirect potable reuse: Uses an environmental buffer, such as a lake, river, or a groundwater aquifer, before the water is treated at a drinking water treatment plant. • Direct potable reuse: Involves the treatment and distribution of water without an environmental buffer.25 Orange County Water District has been providing indirect potable reuse. In the mid- 1990s, OCWD began the planning and construction that created the Groundwater Replenishment System to produce indirect potable water. The process built upon an earlier process to produce water to prevent groundwater intrusion. The process took over ten years to implement and the system is working well. However, it should be noted as being limited because it relies upon a declining supply and it is a lengthy process. Interviewees have noted that OCWD is considering direct potable reuse. The State of California is currently enacting regulations to enable direct potable reuse. One of the advantages of direct potable reuse is the elimination of the loss due to evaporation at the percolation ponds and the efficiency of direct use. In summary, water reuse is a vital part of the portfolio of water for Orange County to insure water resiliency. Water reuse should also be expanded to the practical extent possible. The time to complete such projects is lengthy and needs to be started immediately. However, reuse is only part of the water needed by Orange County and the source problem needs to be addressed. Aquifer Management Managing the aquifer underneath North Orange County created a highly resilient source of water, but it is challenged by the climate change. The main and supplemental supplies of water are diminishing with less precipitation. The use of the aquifer for wet