NASA Report Highlights Need to Retire Drainage Impaired Land in California
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Alarming new space observations revealing increased rates of groundwater depletion in California highlight the urgent need to retire drainage impaired, selenium-filled farmland on the west side of the San Joaquin Valley.
The findings, based on data from the NASA/German Aerospace Center Gravity Recovery and Climate Experiment (Grace), demonstrate that the aquifers for California's Central Valley and the Sierra Nevada have lost nearly enough water combined to fill the Colorado River's Lake Mead, America's largest reservoir, since October 2003. The observations "reflect California's extended drought and increased rates of groundwater being pumped for human uses, such as irrigation," according to the Jet Propulsion Laboratory in Pasadena.
The data was released as Governor Arnold Schwarzenegger, Senator Dianne Feinstein, Senate President Pro Tem Darrell Steinberg, corporate agribusiness and southern California water interests are pushing for the fast-track construction of a peripheral canal and more dams. The data's release also occurs as Feinstein, most likely at the urging of Beverly Hills agribusiness tycoon Stuart Resnick, has recently introduced a "Water Transfer" bill, S 1759, that would allow the re-sale of subsidized water by wealthy Central Valley Project contractors for enormous profits.
Combined, the Sacramento and San Joaquin River drainage basins have shed more than 30 cubic kilometers of water since late 2003, said professor Jay Famiglietti of the University of California, Irvine. A cubic kilometer is about 264.2 billion gallons, enough to fill 400,000 Olympic-size pools. The bulk of the loss occurred in the Central Valley, California's huge agricultural region that receives its irrigation from a combination of groundwater pumped from wells and surface water diverted from elsewhere.
"Grace data reveal groundwater in these basins is being pumped for irrigation at rates that are not sustainable if current trends continue," Famiglietti said. "This is leading to declining water tables, water shortages, decreasing crop sizes and continued land subsidence. The findings have major implications for the U.S. economy, as California's Central Valley is home to one sixth of all U.S. irrigated land, and the state leads the nation in agricultural production and exports."
"Preliminary studies show most of the water loss is coming from the more southerly located San Joaquin basin, which gets less precipitation than the Sacramento River basin farther north," according to Alan Buis of the Jet Propulsion Laboratory. "Initial results suggest the Sacramento River basin is losing about 2 cubic kilometers of water a year. Surface water losses account for half of this, while groundwater losses in the northern Central Valley add another 0.6 cubic kilometers annually."
The San Joaquin Basin is losing 3.5 cubic kilometers a year. More than 75 percent of this is the result of groundwater pumping in the southern Central Valley, primarily to irrigate crops, including those on drainage impaired land filled with selenium and other toxic salts and heavy metals.
The depletion of groundwater supplies is not just a major problem in California, but in India and other countries across the globe. "The California results come just months after a team of hydrologists led by Matt Rodell of NASA's Goddard Space Flight Center, Greenbelt, Md., found groundwater levels in northwest India have declined by 17.7 cubic kilometers per year over the past decade, a loss due almost entirely to pumping and consumption of groundwater by humans," noted Buis.
The latest NASA findings on Central Valley groundwater depletion demonstrate the urgent need to stop the construction of the peripheral canal. The peripheral canal is designed to export more water from the Sacramento Valley and California Delta to southern California and drainage impaired land on the west side of the San Joaquin Valley -- and will only exacerbate the groundwater crisis by continuing to irrigate land that should have never been irrigated. The water policy/water bond package passed by Legislature in November will clear the path to the construction of the canal and Temperance Flat and Sites reservoirs.