Download pdf - Water Replenishment District of Southern California

Projects and Programs
contamination or other anthropogenic (man-made) constituents, now classified as Priority A
Projects. Further, any treatment projects for naturally-occurring constituents would be classified as
Priority B Projects and funded on a secondary priority, on a case-by-case basis, and only if program
monies are still available during the fiscal year. While such projects are of interest to WRD,
availability of funding for them will not be determined until after the budget process.
Projects under the SDWP involve the treatment of contaminated groundwater for subsequent
beneficial use. This water quality improvement assists in meeting the District’s groundwater
cleanup objectives. Thus, funding for the costs of the program is drawn wholly from the Clean
Water Fund.
018 – Dominguez Gap Barrier Recycled Water Injection
This Project involves the delivery of recycled water from the City of Los Angeles Department of
Water and Power’s (“LADWP”) Terminal Island Treatment Plant (“TITP”) Advanced Water
Treatment Facility (“AWTF”) to the Dominguez Gap Barrier (“DGB”). Deliveries of recycled water
to the barrier commenced in late February 2006 and have continued to November 2011 when the
plant was shut down for upgraded and maintenance.
The influent water is being treated with microfiltration, reverse osmosis, and chlorination before
being injected into the DGB. The project is permitted to maintain an overall ratio of 50% recycled
water and 50% potable water up to a maximum of 5 mgd to satisfy regulatory requirements.
Additional water quality requirements, including turbidity and modified fouling index (“MFI”), must
also be met to minimize potential fouling of injection wells in the DGB, which is owned and
operated by the County of Los Angeles Department of Public Works.
While LADWP is responsible for the treatment and delivery of the recycled water and all the water
quality sampling associated with those activities, WRD has responsibility over groundwater
monitoring compliance. As part of the permit, groundwater monitoring is required to measure and
track water quality conditions and to anticipate potential problems before recycled water arrives at
downgradient drinking water wells. In addition, a tracer study was conducted at the start of recycled
water injection (February 2006) through fall 2010 to determine the extent of travel and movement of
the recycled water blend. The tracer study confirmed that adequate mixing and further blending in
the ground is occurring and that groundwater samples being collected are representative of the
recycled water blend.
Recycled water use at the seawater intrusion barriers in Los Angeles County improves the reliability
of a supply that is needed on a continuous basis. Traditionally, water purchases for the barriers have
been viewed as a replenishment function. Therefore, this program is funded 100% through the
Replenishment Fund.
023 – Replenishment Operations
WRD actively monitors the operation and maintenance practices at the LACDPW-owned and
operated spreading grounds and seawater barriers within the District. Optimizing replenishment
opportunities is fundamentally important to WRD, in part because imported and recycled water
WRD Engineering Survey and Report, 2012 V-9