The U.S. Environmental Protection Agency labeled a 15-year effort by farmers and others to reduce selenium runoff into the San Joaquin River a "success story" in a two-page report posted on the agency's website.
EPA's Region 9 office in San Francisco recently issued its report, "Grassland Bypass Project Reduces Selenium in the San Joaquin Basin."
Carolyn Yale, who works in the Region 9 watershed group, said the "Grasslands Bypass Project (GBP) is a very significant component in controlling discharge to the river."
Selenium is a naturally-occurring element in the soils along the west side of the San Joaquin Valley and as farmers converted land into food-production, the selenium was picked up in the irrigation water as it seeped into the soil and then flowed away from the fields as drainage water. Farmers, public water agencies, and numerous State and federal agencies formed the GBP in 1996 to halt selenium from reaching the river.
GBP includes nearly 100,000 acres planted mostly to orchards and some row crops. Farmers have installed micro irrigation systems featuring drip and sprinklers on 60,000 acres in an effort to curtail the amount of drainage water by reducing the amount of water applied to the crops.
"Local water districts have also been active participants in the effort to reduce the drainage reaching the river," explained Dennis Falaschi, manager of the Panoche Drainage District. "These districts have lined canals with concrete or installed underground pipelines for water delivery that has resulted in a reduction of more than 2,000 acre-feet of drainage water."
EPA's Yale pointed to the farmers and water districts as "really valuable players. Forming the regional drainage entity was a crucial element of the program by having farmers and districts working together. We don't want to lose that organizational effort and would like to see more collaborative efforts of that kind."
A reuse component of the Grassland Bypass Project has diverted drainage water to pasture fields and has proven so successful that more than 6,000 acres today are receiving the water. Most of the land is planted to forage grasses that can tolerate higher salt levels in the irrigation water.
The selenium issue surfaced in the 1980s when drainage water from farm fields in other areas of the Grasslands Basin emptied into the Kesterson National Wildlife and Refuge Area.
"It is important to realize that the drains delivering the water to Kesterson were closed at that time," recalled Mike Wade, executive director of the California Farm Water Coalition. "Drainage from the farm land that is included in today's Grasslands Bypass Project was never involved in the issue surrounding Kesterson."
The current reduction of drainage discharge to the San Joaquin River has lowered selenium concentrations to levels below river water quality objectives, according to Falaschi.
Between 1998 and 2009, the EPA report acknowledged that "more than 22,300 pounds of selenium and 80,735 acre-feet of drainage" have been prevented from reaching the river. Selenium discharge into the river during this time dropped by 87 percent with salt reduced by 72 percent and 64 percent for boron.
The load reduction resulted "in the de-listing of Salt Slough (10 miles) in 2008 and three segments of the SJR (totaling 40.4 miles) in 2010," according to the EPA report.
"Our final goal is to eliminate all drainage from the Grasslands Drainage Area from reaching the San Joaquin River," concluded Falaschi.