California prepares to divert toxic irrigation drainage from US wildlife refuge

Short-term solutions to toxic irrigation runoff in the San Joaquin Valley begin this summer. But permanent answers to the problem, which caused a showdown between farmers and environmentalists this spring, still lie beyond a maze of scientific, political, and economic issues.

The focal point of the problem is the clean up of the Kesterson National Wildlife Refuge, contaminated by toxic irrigation drainage from San Joaquin Valley farms.

Irrigation pollution is peculiar to the geology of the western side of the 250-mile long San Joaquin Valley, which cradles five of the nation's top 10 agricultural counties.

Salinity is high in the arid soil here. And impermeable clay under the crops causes a high water table. As acreage is irrigated it must also be drained so that water doesn't suffocate the roots of crops. The constant flushing of water carries with it the salts and concentrations of selenium, an element occuring naturally in the soil. Selenium has been blamed for deaths of plants, fish, birds, and even cattle downstream from the irrigated land.

Fresno County farmers, given a reprieve from a threatened US Interior Department cutoff of federal water early this spring, must cut the flow of drainage into the once lush Kesterson preserve by June 1986.

The Westlands Water District, which serves farmers on the 42,000 affected acres, must find a new and environmentally safe place for the drainage. So the district plans to reduce water flow to the refuge by building 390 acres of earthen storage basins this summer.

The basins are designed to collect irrigation runoff to incrementally slow the flow into the refuge. The district also will build 3,500 acres of evaporation ponds where all drainage from the district must eventually flow. Costs for the two project are estimated at $12 million.

Contaminated water and soil left in the Kesterson refuge remains a problem. But the US Bureau of Reclamation is under an order to clean up the refuge by 1988 and must present a firm plan of action to the California State Water Quality Control Board on July 5.

Last week in Washington, the House subcommittee on water and power rejected an initial Interior Department request for funding for the first phase of a $40 million study of the overall valley drainage problem. Portions of the study would have explored the possibilities of sending valley drainage to San Francisco and Monterey bays.

Based on the Kesterson problem itself, those appear to be politically unacceptable ideas. The Central Valley Project, designed to take valley drainage all the way to San Francisco Bay, was halted midway by Bay Area resistance. The plan was halted at Kesterson, where the drainage water now collects.

Long-range planning for valley drainage is urgent because while the problem only effects 42,000 acres today, 2 million acres will eventually need drainage, explains Larry Hancock, assistant regional director of the federal Bureau of Reclamation in Sacramento.