Tackling water pollution Stockton Record - March 24, 2005 By Dana Nichols LOCKEFORD -- Bill Koster is thinking about trying a little California grass. No, not that kind of grass. Koster is thinking about varieties like barber's sedge, Baltic rush or purple needlegrass. The Vernalis farmer learned about the native grasses Wednesday during a workshop on controlling farm water pollution. He's considering planting the grasses along drainage ditches as a way to filter pollutants out of runoff. A bonus, in Koster's view, is that once established, the native grasses crowd out other kinds of grasses that can become weedy pests in fields. "I'm tired of spraying, and some of the stuff is getting resistant to Roundup," he said, referring to a widely used herbicide. Koster was among 80 people who turned out for the farm water pollution field day at the Natural Resource Conservation Service Plant Materials Center in Lockeford. Workshop sessions covered everything from how to control pesticide spray drift to ways of managing water pollution from vineyards. The San Joaquin County Resource Conservation District and the San Joaquin County and Delta Water Quality Coalition sponsored the half-day of workshops. The coalition formed to offer local farmers a mechanism to monitor waterways for pollution and comply with state pollution control rules that went into effect in 2003. The coalition and others around the state have an April 1 deadline to turn in reports on the results from the first full year of tests of winter storm and summer irrigation runoff. John Meek, who runs the local coalition, told those gathered at the workshop that summer irrigation season tests of area rivers came up clean. But he said five sites tested toxic during winter rains and that the coalition is now doing more detailed tests to determine the kinds of chemicals and where they may have originated. Meek urged those present to check weather reports before spraying. "If you see rain in the forecast, don't put it on," he said. The problem is that organophosphate pesticides such as chlorpyrifos are extremely toxic and dissolve easily into water, said Mick Canevari of the University of California Agricultural Extension. Canevari said organophosphates kill tiny aquatic organisms at concentrations of 80 parts per billion. That's about the same as two drops of pesticide in an acre-foot of water -- enough water to cover an acre 1 foot deep. "It all has to do with irrigation management and tail water coming off the field," he said during a workshop session. Canevari suggested using the minimum amount of water needed for irrigation and using catch basins and recirculation pumps to prevent runoff from getting into rivers. An option when runoff can't be avoided is to use plants, especially native grasses, to filter and clean the water before it gets back to drainage ditches, said John Anderson, who has grown native California grasses on his farm near Winters since the late 1970s. Many farmers and irrigation districts have kept canal banks bare since herbicides such as Roundup became widely available in the 1970s, Anderson said. The logic is that bare banks give the water maximum room to flow and the herbicides also kill weeds that could spread to fields. The downside is that bare banks erode and may have to be dug out every year. Also, bare banks allow pollution to flow easily back into the water. So Anderson and others persuaded his local irrigation district to try planting native grasses on canal banks. The result: more stable banks, more birds and fish to eat mosquitoes and other insect pests, and more plant matter to filter out pollution. Also, he said grasses like barber's sedge don't interfere with the water flow in the canal. And once established, they prevent invasive annual weeds from getting a foothold. But that prompted Koster to worry if the native perennial grasses might also be trouble. "Are these invasive species that will regrow in my field?" he asked. No, Anderson said. "These are really slow-growing." Anderson said the native grasses also are adapted to burning. That means they'll grow back from their roots after a fire that crisps pesty annual grasses. # http ://www.recordnet.com/articlelink/032405/news/articles/032405-gn-17.php