While it's crucial to repair the plumbing in the fragile Sacramento-San Joaquín Delta, California has many water needs that are being overlooked.
Largely missing from the debate is the management of California's groundwater resources, which in dry years provide nearly 40 percent of the state's supplies. As the state enters a new phase of emphasizing delta solutions, these groundwater resources can't be ignored.
A recent study by the U.S. Geological Survey warns that the Central Valley aquifer is being depleted at an unsustainable rate, even though the state has enjoyed numerous wet years since the drought of the early 1990s.
"Unless we start doing very large-scale recycling, we run out of groundwater in the valley," Jay Famiglietti, director of hydrologic modeling at the University of California at Irvine, told The Sacramento Bee. "It might be 50 years or 100 years, but it is going to happen."
As with other studies, the USGS report finds that the most severe overdrafting of groundwater is occurring in the Tulare basin of the San Joaquín Valley, which is home to irrigated farmland and large dairy operations.
Scientists estimate the annual overdraft of the Tulare basin to be about 1.4 million acre-feet of water yearly -- enough to supply more than 2.8 million households. Along with depleting groundwater, agricultural operations are contaminating groundwater with nitrates -- a health threat to all those who depend on wells for their drinking supply.
But the San Joaquín Valley isn't the only place where groundwater is being overpumped, land has subsided and aquifers are in danger of being depleted.
The Salinas Valley and other Central Coast basins have a groundwater problem. So do farmers in the Sacramento area. Excess pumping causes a reduction in flow down the Cosumnes River, which supports wild salmon runs.
California's groundwater and surface water supplies are connected, but California, unlike many Western states, has no law that governs groundwater use.
Hundreds of local agencies have some jurisdiction over groundwater, but monitoring of usage is spotty. As the legislative analyst's office has noted, there is "a lack of comprehensive data on statewide water use."
State and federal leaders must be part of the push for better groundwater management. In the Central Valley, groundwater makes up 80 percent of water use, but gets much less attention than management of streams, rivers and the delta. That needs to change if California's cities and farms are going to survive the droughts in our future.
-- Merced Sun-Star, July 30