San Joaquin River DOTMDL -- Technical Working Group

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

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

"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

The San Joaquin County Resource Conservation
District and the San Joaquin County and Delta
Water Quality Coalition sponsored the half-day of

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

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

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

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. #

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