Overview -- Groundwater Management in California Western States Water Council April 2004

GW resources background Supports about 30% of California urban & ag needs in average water years Important drought resource Supplies majority of state’s public water systems (largest urban agencies use surface water, almost all small systems use groundwater)

Rights to use of groundwater Not administered by State (unlike surface water) Developed through case law

Case law examples City of Los Angeles v. City of San Fernando (1975) – mutual prescription not applicable between public agencies Niles Sand & Gravel Co. v. Alameda County Water District (1974) – public agencies can store water underground & recover stored water

Impetus for GW management Seawater intrusion – widespread by 1950s Overdraft, land subsidence Fear of exports State financial assistance Other

Physical realities of GW management Limit/regulate extraction Develop new in-basin surface supply Bring in new imported water source Storage/conjunctive use projects require available aquifer capacity, conveyance, and surface water source

GW management techniques Basin adjudication in court (19) Special or general act districts AB 3030 plans (>160 agencies) County ordinances (28)

Basin adjudications Expensive Entail years in court system

AB 3030 plans Enabling legislation enacted in 1992 Plan adoption is voluntary Hydrologic/hydrogeologic/political boundaries often differ Plans may be multi-agency Are they effective?

GW storage projects increasing Existing “large” projects w/ ballpark of 10 MAF total managed capacity More than $500M in state financial assistance authorized Many “small” and “medium” projects now in planning stages, reflecting availability of substantial state funding