2020-103 - Approving the Water Supply Assessment

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Basin 8-1 Overview As the City of La Habra currently depends on local groundwater to meet approximately 40 percent of its water consumption; preserving the sustainability of the La Habra -Brea Management Area is essential. Currently (and historically), the City of La Habra manages (and has managed) the La Habra -Brea Management Area through management plans and programs for groundwater levels, basin storage, and water quality. By January 2020, the City will manage the La Habra -Brea Management Area through a Groundwater Sustainability Plan under SGMA, which will describe the monitoring program and ensure that no undesirable results occur in the future. 2. OCWD MANAGEMENT AREA The OCWD Management Area covers an area of approximately 260 square miles within Basin 8-1, which represents approximately 89 percent of the land area of Basin 8-1. Ninety-eight percent of the groundwater production within Basin 8-1 occurs in the OCWD Management Area. Groundwater produced within the OCWD Management Area provides approximately 70 percent of the total water supply for a population of around 2.4 million residents. Since its formation by the California Legislature in 1933, OCWD has been the managing agency for the majority of Basin 8-1, also referred to as the Coastal Plain of Orange County Groundwater Basin. As a special act district listed in Water Code § 1072(c)(1), OCWD is the exclusive local agency within its jurisdictional boundaries with powers to comply with SGMA. Water demands within the OCWD Management Area have grown from approximately 150,000 acre-feet per year (afy) in the mid-1950s to a high of approximately 366,000 afy in water year 2007-08. OCWD operates an extensive network of recharge basins to increase recharge of surface water into the groundwater basin to support groundwater production. OCWD monitors the basin by collecting groundwater elevation and quality data from nearly 700 wells, including over 400 OCWD-owned monitoring wells, manages an electronic database that stores water elevation, water quality, production, recharge and other data on over 2,000 wells and facilities within and outside OCWD boundaries. An OCWD-operated water recycling plant provides up to 100 million gallons per day of advanced tertiary -treated wastewater that supplies recharge operations and a seawater intrusion barrier operated to protect the basin's water quality. OCWD manages groundwater storage and water levels within an established operating range which has resulted in sustainable conditions with no unreasonable and significant undesirable results. The Sustainability Goal for the OCWD Management Area is to continue to sustainably manage the groundwater basin to prevent conditions that would lead to significant and unreasonable (1) lowering of groundwater levels, (2) reduction in storage, (3) water quality degradation, (4) seawater intrusion, (5) inelastic land subsidence and (6) adverse impacts on hydrologically connected surface water. 2017 BASIN 8-1 ALTERNATIVE Overview 6