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Methods

The data and information on this site originates from publicly available sources. Many of these sources, however, are not in an electronic form. The data presented was exhaustively extracted from reports, legal documents, management plans, and other sources. CCSC developed these databases of available quantitative information for water management in the region to support on-going projects assessing local water reliance and the future of L.A. water.

Information on water demand and supplies for agencies throughout the regions was primarily derived from the 2010 Urban Water Management Plans. Urban Water Management Plans (UWMPs) are prepared by California's urban water suppliers every five years to support long-term resource planning and ensure that water supplies are available to meet existing and future water demands. We used the 2010 documents to create the current database of annual water demand, supplies, supply sources, and water transfer agreements. Every urban water supplier that either provides over 3,000 acre-feet of water annually or serves 3,000 or more connections is required to assess the reliability of its water sources over a 20-year planning horizon considering normal, dry, and multiple dry years. The management plans provide information about how agencies calculate their future water needs and estimate water availability.

Each adjudicated basin in the region, where rights are legally determined among pumpers, has a watermaster that oversees annual pumping and recharge operations. They publish Annual Groundwater Master Reports for their board members, which are also available to the public. The reports provide information on groundwater levels, annual pumping rights for pumpers, allocations to large agencies, and more. We used previous watermaster reports from 2011 through 2013 to develop the current database and analysis.

Each adjudicated groundwater basin also published an Adjudication that describes the legally binding agreement among pumpers. All adjudications were approved by courts and specified pumping rights, court-appointed watermasters, and governance structures of leadership boards. We used the adjudications to extract data on pumping rights by rights holders at the time of original adjudication, which ranged from 1949 to 1998.

The California State Water Resources Control Board (SWRCB) publishes the most accurate estimates of Residential Per Capita Use Esimates for major retailers throughout the state. Beginning in 2014, the SWRCB required utilities and city water supply agencies to report per capita consumption in residencies using standardized methods that created comparable data for consumption throughout the state. By 2015, water agencies had updated assessments of service area populations and consumption for calculating per capita use, which helps assess success in meeting mandatory water use reduction targets as part of the state's response to the recent servere drought.

We compiled the data in spreadsheet software and created electronic GeoJSON databases to support mapping. Each entity has associated shapefiles with data as attributes, which are mapped using the open-source JavaScript library Leaflet. The web pages use HTML, CSS, and JavaScript.

References

  1. 2010 Urban Water Management Plans. The complete list of UWMPs is available from the California Department of Water Resources.

  2. California State Water Resources Control Board (2016). Water Conservation Portal: Conservation Reporting. Sacramento, CA.

  3. MWD (2007). Groundwater Assessment Study (Chapter IV). Metropolitan Water District of Southern California. Los Angeles, CA.

  4. Central and West Basin Water Replenishment District v. Charles E. Adams et al., No. 786,656, Superior Court of the State of California, Los Angeles County, 11 October 1965. (The original adjudication for the Central Groundwater Basin).

  5. Central and West Basin Water Replenishment District v. Charles E. Adams et al: Third Amended Judgment, No. 786,656, Superior Court of the State of California, Los Angeles County, 18 December 2013. (The recently updated adjudication for the Central Groundwater Basin).

  6. City of Los Angeles v. City of San Fernando et al., No. 650079, Superior Court of the State of California for the County of Los Angeles, 26 January 1979. (The adjudication for the San Fernando groundwater basin and ULARA groundwater basin area).

  7. City of Pasadena v. City of Alhambra et al., No. L.A. Number 19610, Supreme Court of California, 3 June 1949. (The adjudication for the Raymond Groundwater Basin).

  8. DWR (2013). Watermaster Service in the West Coast Basin of Los Angeles County (West Coast Basin Watermaster Report). Sacramento, CA: California Department of Water Resources (West Coast Basin Watermaster)

  9. Six Basins Watermaster. (2013). Annual Report for Calendar Year 2012. Lake Forest, CA: Prepared by: Wildermuth Environmental

  10. ULARA Watermaster. (2013). 2011-12 Annual Report: Upper Los Angeles River Area Watermaster

  11. Upper San Gabriel Valley Municipal Water District v. City of Alhambra, et al., No. 924128, Ammended Judgement (1989). Original Judgement filed 29 December 1972. (Updated adjudication for the Main San Gabriel Groundwater Basin).