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Land Use and Resource Management Plan for the Primary Zone of the Delta — Water

In California, rainfall runoff and snowmelt are captured in reservoirs to redistribute to urban and agricultural customers and for environmental uses. About 75% of the State's water originates north of Sacramento; and about 75% of the State's water needs occur south of Sacramento.

Water bound for distribution through both the State Water Project and the federal Central Valley Project is taken from the south Delta. In addition, water to serve some Bay Area urban users is taken from the Delta. The State project has contracts to export up to 4.2 million acre feet per year from the Delta and the federal project another 3.3 million acre feet per year. Of the water in the two developed water systems, about 83% is used for agriculture and about 17% is for "urban" uses. About two-thirds of the State's population gets at least a portion of its drinking water from the Delta. In addition, Delta farmers also have rights to irrigate with water taken directly from Delta sloughs and channels.

Water quality in the Delta is regulated by the Regional Water Quality Control Boards through permit review of "point" discharges, such as discharges of treated water from sewage treatment plants and discharges to land. Water quality concerns related to drinking water include salinity intrusion, wastewater discharges, agricultural drainage water, trihalomethane precursor formation, and untreated stormdrain water.

The State Water Resources Control Board and the Regional Boards also designate beneficial uses of the State's waters. In the Delta, beneficial uses include: municipal and domestic supply; agriculture; industry; groundwater recharge; navigation; recreation; wildlife habitat; fish migration and spawning; and preservation of rare and endangered species.

During low flow and drought conditions, increased salinity of water of the western Delta can have a detrimental effect on agriculture in the area as well as the quality of drinking water supplies.

Water is being applied to some Delta lands to restore wetland habitats. This includes some areas proposed for permanent wetland status and thousands of acres of seasonally-flooded agricultural lands. Application of water can also result in enhanced habitat for mosquitoes, a recognized pest and health hazard.

Goal: Protect long-term water quality in the Delta for agriculture, municipal, industrial, water-contact recreation, and fish and wildlife habitat uses, as well as all other designated beneficial uses.

Water Findings:
  • F-1. Water flows from the Central Valley watershed into the Delta. The Delta's natural and constructed waterways transport water towards lower elevation areas and San Francisco Bay, and to the State and federal project pumps.
  • F-2. About 83% of the State's developed water is used for agricultural irrigation. Developed water means water stored and managed for urban, agricultural, or environmental uses.
  • F-3. Most Delta farms use water taken directly from Delta sloughs and rivers under riparian water rights through unscreened diversions.
  • F-4. Urban water users use about 17% of the State's developed water; residential water use is about half that amount.
  • F-5. Other water uses which use approximately 132 million acre feet per year include: wildlife habitat, salinity control, wild and scenic rivers, and other natural uses.
  • F-6. The Central Valley Regional Water Quality Control Board has designated the following beneficial uses in the Delta:
    • Municipal and Domestic Supply
    • Agricultural Supply: Irrigation and Stock Watering
    • Industrial Process and Service Supply
    • Groundwater Recharge
    • Freshwater Replenishment
    • Navigation
    • Hydroelectric Power Generation
    • Water-Contact and Nonwater-Contact Recreation
    • Freshwater Habitat
    • Preservation of Rare and Endangered Species
    • Fish Migration/Fish Spawning
  • F-7. Water quality is regulated by the State Water Resources Control Board and both the Central Valley Regional Water Quality Control Board (Central and Eastern Delta) and the San Francisco Regional Water Quality Control Board (Western Delta) under both State and federal laws.
  • F-8. Use of water is regulated by the State Water Resources Control Board and by the federal government as it affects critical environmental issues.
  • F-9. Water in the Delta generally meets current standards for beneficial uses, including drinking water standards once the water is treated.
  • F-10. Water quality issues include: ocean salinity intrusion; materials carried in agricultural return waters; runoff from urban areas in the Delta watershed including discharge of treated municipal wastewater; formation of trihalomethane precursors and other disinfection by-products in drinking water resulting from chemicals added during water treatment processes; possible local problems associated with on-site sewage disposal; and on-land disposal of biosolids (sludge) and treated wastewater.
  • F-11. Salinity is a key Delta water quality issue which affects land use, and which is under regulation of State and federal agencies.
  • F-12. The impacts of non-point source discharges including agricultural discharges, both within and upstream of the Delta, are currently being studied and subjected to increasing regulation.
  • F-13. Water is needed to enhance seasonal and year-round wildlife habitat in the Delta such as flooding agricultural fields in fall and winter. Seasonal flooding is of particular value to migratory waterfowl.
  • F-14. Flooding in the Delta, if not properly managed can create habitat for mosquitoes, a concern where wetlands and population centers are near to each other.
  • F-15. Water-contact recreation is popular in the Delta and requires appropriate water quality.
  • F-16. Water regulators, water producers, and water consumers all hold interests and responsibilities for various aspects of the State's waters. The responsibilities of various agencies are set out in State and federal laws and regulations.
  • F-17. Transport of State and federal project water through the Delta does result in levee erosion and reverse flows and may detrimentally affect some fish species.
  • F-18. Recreational boating activities may degrade water quality by increasing turbidity, release of oily wastes, particularly from outboard motors, anti-fouling paints, and release of untreated sewage and other wastes.
  • F-19. Commercial shipping vessel activities may degrade water quality by increasing turbidity, releasing bilge water, and discharging other solid and liquid wastes.
  • F-20. The State has contracts, which are enforceable in court, with a number of entities in the Delta, including the North and South Delta Water Agencies and the East Contra Costa Irrigation District, that deal with specified needs in the Agencies' boundaries for water for agricultural use.
  • F-21. In 1992, Governor Pete Wilson established a comprehensive state water policy. In 1994, the Governor and the Secretary of the Interior, and others, signed the CALFED accord setting water policy for the next three years and outlining a new process for a long-term resolution of California's water issues.
Water Policies:
  • P-1. Local governments shall ensure that salinity in Delta waters allows full agricultural use of Delta agricultural lands, provide habitat for aquatic life, and meet requirements for drinking water and industrial uses.
  • P-2. Local governments shall ensure that design, construction, and management of any flooding program to provide seasonal wildlife habitat on agricultural lands shall incorporate "best management practices" to minimize mosquito breeding opportunities and shall be coordinated with the local vector control districts. (Each of the four vector control districts in the Delta provides specific wetland/mosquito management criteria to landowners within their district.)
  • P-3. Water agencies at local, State, and federal levels shall work together to ensure that adequate Delta water quality standards are set and met and that beneficial uses of State waters are protected consistent with the CALFED (see Water Code Section 12310 (f)) Record of Decision dated August 8, 2000.
Water Recommendations:
  • R-1. The Delta waterways should continue to serve as a primary transportation system moving water to the State's natural and developed water systems.
  • R-2. Delta water rights should be respected and protected.
  • R-3. Programs to enhance the natural values of the State's aquatic habitats and water quality will benefit the Delta and should be supported.
  • R-4. Programs to regulate agricultural drainage in the Delta should be accompanied with education programs, be implemented over time, and should, where needed, provide financial assistance such as grants and interest-free loans to ensure compliance. Any regulation of Delta agricultural discharges must recognize that a) dischargers must be permitted to discharge back to the channels any dissolved solid loads that were derived from the channels in irrigation diversions and seepage inflows, and b) any net addition of dissolved carbon compounds must be compared to the addition of such compounds that would occur with any other land use option that would provide equal protection of the land and channel configuration and would consume no more water.
  • R-5. Water for flooding to provide seasonal and year-round wildlife habitat should be provided as part of State and federal programs to provide water for wildlife habitat.
  • R-6. Water quality monitoring programs should measure Delta waters to ensure they meet water-contact recreation and other water quality standards.
  • R-7. State and federal water projects are beneficiaries of the Delta waterways and levees; the projects should fund that portion of levee erosion caused by water transport and should continue programs that fund protection of Delta levees.
  • R-8. Water quality at Delta drinking water intakes should be maintained or enhanced.