Situated in a semi-arid region of southern California, the Upper Los Angeles River Area (ULARA) is a major water supply source for the City of Los Angeles metropolitan area. This has caused long-term legal battles over water rights which ultimately culminated in the 1979 Superior Court adjudication of the area in the case of City of Los Angeles vs. City of San Fernando, et al. As the cumulative result of this case, the Court upheld the Pueblo Water Rights of the City of Los Angeles to all water in the ULARA groundwater basins that is derived from precipitation (infiltration of direct rainfall plus surface water runoff).
The Court's Final Judgment (January 1979) includes provisions and stipulations regarding water rights, storage of water, stored water credits, and arrangements for physical solution water for certain parties as recommended by the Supreme Court. A separate stipulation was filed in Superior Court appointing a ULARA Watermaster, to oversee water usage and basin issues. The author is the 3rd Court-appointed ULARA Watermaster since the Final Judgment of 1979.
The 328,500-acre ULARA area encompasses the entire watershed of the Los Angeles River and its tributaries above (north of) the point in the river near the junction of the Los Angeles River and the Arroyo Seco. Four groundwater basins and their adjoining hill and mountain areas comprise ULARA; from largest to smallest in surface area, these four groundwater basins are known as the San Fernando, the Sylmar, the Verdugo and the Eagle Rock basins. Groundwater recharge to these basins occurs via the following sources: deep percolation from direct rainfall; infiltration of surface water runoff; and infiltration of a portion of the water that is imported and delivered for use within these basins. Artificial recharge also occurs in the San Fernando Basin via the use of spreading basins whenever excess rainfall and runoff are available.
Significant challenges in ULARA over the long-term will continue to be: the accumulation of stored water credits in the San Fernando Basin; ongoing contamination of groundwater in the San Fernando, Verdugo and Sylmar basins; elevated concentrations of nitrate in the groundwater in Sylmar Basin; and the need to increase recharge into the local groundwater basins by different methods, at different locations and depths, and by using different sources of water. This need for increased recharge is particularly important for the San Fernando Basin.
Groundwater contamination from volatile organic compounds (VOCs) and hexavalent chromium continues to be a serious problem for water-supply in the eastern portion of the San Fernando Basin. The cities of Burbank, Glendale and Los Angeles continue to enlist the assistance of key regulatory agencies including the United States Environmental Protection Agency (USEPA), the Regional Water Quality Control Board - Los Angeles (LARWQCB), and the State Department of Toxic Substances Control (DTSC) to help expedite the cleanup of the contaminated soils and aquifers within San Fernando Basin. Pumping of excessive concentrations of chromium by certain wells and limitations of existing treatment facilities to treat those excessive concentrations have also become more recent problems. In addition, various gasoline components continue to impact and/or threaten municipal-supply water wells owned by the Crescenta Valley Water District in the Verdugo Basin. In the Sylmar Basin, nitrate concentrations have been increasing in recent years in wells operated by the City of San Fernando; Los Angeles has one well that has been impacted by TCE in this basin.
An ongoing activity of the Watermaster continues to be the review and the approval/denial of the possible plans for infiltration of stormwater collected at all new development and/or redevelopment projects within the San Fernando Basin portion that lies within the City of Los Angeles. These stormwater collection plans, as prepared by the engineer for the developer, are part of the Standard Urban Stormwater Mitigation Plan (SUSMP) program of the LARWQCB.
Tonight's talk will focus on the basic history of the adjudication, typical Watermaster duties, the local surface and subsurface groundwater conditions in the watershed and in the 4 groundwater basins which comprise ULARA, and typical water level and water quality problems in those groundwater basins.