UWM Plan - Municipal Water District of Orange County

Section 3
Water Sources and Supply Reliability
subsurface inflow of 2,246 AFY. Average subsurface outflow to the ocean is estimated to
be about 450 AFY.
SJBA is currently in the process of updating their Groundwater Management Plan.
MWDOC is assisting in the effort by providing groundwater modeling of the basin
resources, including several groundwater desalters and an ocean water desalination
project at the mouth of the basin. Through these current efforts, the Groundwater
Management Plan is expected to update the long term sustainable production out of the
basin and develop an implementation plan of how to achieve such production and
manage the basin through wet and dry cycles. The work is expected to be completed in
2011 with implementation to follow. The overall objectives include developing and
maintaining a reliable, good quality and economical local water supply for the residents
in the Basin by maximizing use of local ground and surface water from, the San Juan
Creek and its tributaries and the local ocean water, with due consideration for the
preservation and enhancement of the environment, including, but not limited to, natural
resources, fish and wildlife, infrastructure improvements and the cultural heritage of the
area.
Groundwater Production
The SJBA completed Phase I of San Juan Basin Desalter Project in December 2004. The
original capacity of the plant was projected to reach 4,800 AFY, although numerous
problems have occurred, including pollution of City of San Juan Capistrano wells with
MTBE. The groundwater desalter plant is currently being expanded to be able to produce
about 6,000 to 7,000 AFY and granular activated carbon treatment is being added to
remove MTBE. Additionally, SCWD constructed a 1 million gallons per day (MGD)
Groundwater Recovery Facility (GRF) that came online in FY 2007-2008. The GRF was
built initially for 1,300 AFY but production is currently limited to about 800 AFY by
water rights restrictions and the capacity of a single well. The plant extracts and treats
brackish groundwater using Reverse Osmosis and iron and manganese removal due to
high mineral content. SCWD plans to expand the GRF facilities as well as adding another
well or two. When complete, the project is expected to extract up to 2,000 AFY from the
basin. Expansion of production requires either agreement with SJBA or confirmation of
an additional water right by the State Water Resources Control Board.
3.3.3. La Habra Basin
No groundwater management plan is available for the La Habra Basin. However, the
following sections are written, with assistance from the City of La Habra, to describe the
basin.
Municipal Water District of Orange County
2010 Regional Urban Water Management Plan
Final
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