Farmers heard this week that they are doing a good job of keeping pollutants out of streams, but they have deeper concerns about groundwater contamination.
The East San Joaquin Water Quality Coalition reported continued progress in 2013 against pesticides and other substances that can taint surface water.
The pesticide chlorpyrifos, for example, was detected just once last year compared with 27 times in 2008, the annual report for the farmer-funded group said.
“Over the course of the years, you guys have made a lot of changes in your operations, and things have improved dramatically,” said Mike Johnson, the Davis-based consultant who manages the testing.
He and other leaders warned that the job could be trickier as the coalition moves into groundwater, as required by the state. The key issue is nitrates, a fertilizer residue that could sicken people who drink from public wells.
Several hundred coalition members turned out for a pair of meetings Wednesday at the Stanislaus County Agricultural Center, off Crows Landing Road. The meetings will be repeated Wednesday in Merced.
The coalition’s nearly 4,000 members have more than 700,000 acres of irrigated farmland in the parts of Stanislaus, Merced and Madera counties that are east of the San Joaquin River. It is one of seven such groups that watch for farm-based pollutants under the supervision of the Central Valley Water Quality Control Board, a state agency. They do not cover dairy farms, which are under a separate program.
The board has allowed the coalitions to do the monitoring since 2004 as an alternative to direct, and more costly, regulation by the state. Farmers who do not join these groups have to get waste discharge permits on their own.
“Nobody needs to have one of these permits individually,” said Parry Klassen, a fruit grower and executive director of the east side coalition. “They are too complicated, too expensive.”
The state renewed its support for the coalition approach in 2012, which is also when it launched the groundwater effort. The decision drew criticism from environmentalists, who did not think farmers could police themselves.
The coalition has educated members about how to keep pollutants out of waterways: Don’t spray in windy conditions; create berms or basins to catch irrigation water so it does not run off; use drip systems or microsprinklers to reduce the volume of water.
A key part of the nitrate effort will involve limiting nitrogen fertilizer use to what the crops actually take up, so little is left to leach into the aquifers.
The issue has come to the fore thanks in part to a University of California at Davis report that raised concerns about drinking-water wells in the Tulare Lake Basin and Salinas Valley.