California Code of Regulations › Title 14 - Natural Resources › Division 9 - Delta Protection Commission › Chapter 3 - Regulations Governing Land Use and Resource Management in the Primary Zone of the Sacramento-San Joaquin Delta › Section 20080 - Water

Current through Register 2024 Notice Reg. No. 28, July 12, 2024
(a) Overview
In California, rainfall runoff and snowmelt are captured in
				  reservoirs to redistribute to urban and agricultural customers while meeting
				  environmental requirements. About 75 percent of the State's water originates
				  north of the Delta; and about 75 percent of the State's water needs occur south
				  of the Delta.
Water bound for distribution through both the State Water
				  Project (SWP) and the federal Central Valley Project (CVP) is taken from the
				  south Delta. The CVP has contracts to divert 3.3 million acre feet per year,
				  which supplies primarily agricultural land south of the Delta but also supplies
				  urban areas and wildlife refuges. In addition, water to serve some Bay area
				  urban users is taken from the Delta. The SWP has contracts to divert 4.2
				  million acre feet per year from the Delta, which supplies primarily urban uses
				  but also supplies agricultural uses south of the Delta. On average, the
				  projects export a total of about 5 million acre feet annually.
About two-thirds of the State's population gets at least a
				  portion of its drinking water from the Delta. In addition, Delta farmers and
				  irrigation districts have rights to irrigate with water taken directly from
				  Delta sloughs and channels.
Because the Delta drains the Sacramento River and San Joaquin
				  River watersheds, urban stormwater runoff and waste discharges from upstream
				  and adjacent areas enter Delta waterways and cause water quality problems.
				  Low-flow years generally carry higher concentrations of waste discharges and
				  agricultural runoff and drainage than do wet years.
Some treated municipal and industrial wastewater, untreated
				  urban storm water, and agricultural runoff and drainage enter the Delta
				  directly. Other urban and agricultural discharges from upstream in the
				  watershed enter the Delta along with the river flows. Seepage onto Delta
				  islands from adjacent channels and drainage from the agricultural lands are
				  released back to the Delta channels at hundreds of locations.
The Central Valley Regional Water Quality Control Board
				  (Board) has identified the Delta as impaired by a number of pollutants,
				  including some pesticides, low dissolved oxygen, electrical conductivity
				  (salinity), and mercury (naturally occurring in the Cache Creek watershed, as
				  well as a legacy of the large-scale hydraulic mining of the Sierra Nevada in
				  the late 1800s). Designation as an impaired water body by the Board, relevant
				  to certain water quality criteria or other stressors, is variable depending on
				  portions of the watershed within the Delta. Delta fish have elevated levels of
				  methylmercury, which poses a risk to humans and wildlife that eat the fish on a
				  regular basis. As of 2009, the Board has adopted a threshold called a total
				  maximum daily load (TMDL) for dissolved oxygen and is developing a TMDL for
				  methylmercury in the Delta.
The daily tidal cycles and the San Joaquin River contribute
				  most of the salinity to the Delta. During periods of high Delta inflows,
				  salinity is low; during periods of low Delta inflows, the salinity level rises.
				  Salinity in the Delta is managed by a mix of releases from upstream reservoirs,
				  Cross Channel Gate operations, Delta outflow, and exports from the Delta. The
				  Delta is governed by water quality standards for municipal and industrial uses,
				  agricultural uses, and fish and wildlife, all of which are currently under
				  review by the State Water Resources Control Board. The combination of organic
				  matter (decaying vegetation), bromide in the seawater, and disinfectants used
				  in water treatment plants produce disinfection byproducts that may pose heath
				  risks.
The State Water Resources Control Board and the Regional
				  Boards 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.
(b) Goals
Protect and enhance 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 beneficial uses.
(c) Policies
(1) State, federal and local agencies shall
				be strongly encouraged to preserve and protect the water quality of the Delta
				both for in-stream purposes and for human use and consumption.
(2) Ensure that Delta water rights and water
				contracts are respected and protected, including area of origin water rights
				and riparian water rights.