(April 4 — By Jerry Meral, Special to The Bee)
While more visible water conflicts rage in California, such as calls for new dams throughout the Central Valley and disputes over the need for water to save endangered fish, a lesser-known water crisis threatens the viability of much of California's agriculture, and even the water supply of some Central Valley cities. That crisis is over-reliance on water from wells: groundwater overdraft.
Some basic facts about California's underground water supply:
About a third of the water used in California comes from underground.
The underground water supply is huge: equal to hundreds of Folsom Reservoirs.
We are seriously overdrawing our groundwater account. This is causing land subsidence, in some areas as much as 28 feet. Subsidence disrupts canals and causes flooding problems. Once subsidence takes place, the underground storage capacity can never be replaced.
Overdraft makes people have to deepen their wells. This can cost as much as half a million dollars for an agricultural well. Deeper wells tend to draw poorer-quality water.
In droughts, well water is what keeps farmers and many cities going. A properly managed underground water supply fills in wet years, and then is used to get through droughts.
There is no difference between surface and groundwater. If there is too much pumping of groundwater, nearby streams and rivers are depleted, harming fish and wildlife, and also those with a right to use the water in the streams.
Overpumping groundwater can harm plants and trees.
We have a huge problem, but there is time to solve it. We are not about to run out of groundwater, but the continuing drought is making matters much worse. Demand for new wells is growing fast, and more groundwater is being pumped.
While most urban areas manage their groundwater wisely, in the Central Valley there is very little restriction on pumping. It would not be wise to suddenly eliminate groundwater overdraft: the impact on agriculture would be enormous. Pumping controls should be gradually phased in, restricting pumping and allowing groundwater to be traded between those with a right to pump.
Groundwater districts could be established cooperatively by counties and water agencies. By including county government in this program, all pumpers - whether inside or outside organized water districts - would have a voice in the new system. The new districts would establish targets for groundwater pumping, with the goal of stabilizing overdraft over a period of years.
A fee would be placed on non-residential pumping to pay to administer the system and monitor groundwater pumping and well levels. All groundwater users would have to report their use.
Groundwater rights would be assigned to landowners, but they would collectively have to reduce their use to meet the goal established by the local district. The landowners would be allowed to gradually reduce pumping levels through a "pump and trade" system where the right to pump would be traded between landowners. This will assign a higher value to groundwater, and result in investment in efficient irrigation technology. It is important to recognize the true value of groundwater. Protections for the environment would have to be included.
The alternatives to this system are:
Lengthy litigation to establish the rights of landowners and pumpers. Although this is often done in urban areas, it is probably not practical in the enormous Central Valley.
State regulation of groundwater, as is done in all other western states. This is strongly resisted by groundwater users. The state role could be to simply make sure the new district system is set up and working properly.
Heavy taxes on groundwater pumping, to force reduced use. Groundwater users would strongly resist such new taxes.
California must begin to get its huge groundwater overdraft under control, or face severe economic consequences for cities and agriculture in years to come. Something must be done to avoid handing the next generation of Californians an unsustainable groundwater supply.
The "pump and trade" proposal offers a market-driven solution which can be gradually implemented without severe economic disruption. Legislation is needed to create this system.
Jerry Meral, former deputy director of the California Department of Water Resources, directs the Natural Heritage Institute California Water Program.