Where Fields of Green Lead to Dirty Rivers

The Central Valley’s Holy Trinity of sun, dirt and water embraced Tom Maring’s baby tomato plants.

Irrigation water snaked across the field, giving the transplants their first drink of the season. The overflow spilled into a drainage ditch and then on to the San Joaquin River a few miles away.

The watering started in early May and will be repeated every week or so until the mid-September harvest.

As the irrigation runoff leaves the brown clay fields of the valley’s west side, it will carry the residue of the herbicides and pesticides Maring sprays on his tomato plants to ward off weeds, bugs and fungus. Ultimately, the chemicals will wind up in the chocolate brown waters of the San Joaquin.

Most of the river is contaminated with pesticides, as are hundreds of miles of streams, sloughs and drainage canals in the Central Valley’s intricate plumbing system. Beyond, the chemicals foul parts of the Sacramento-San Joaquin Delta.

The government has long looked the other way--or didn’t look at all. Preoccupied with industrial and municipal polluters, state and federal laws for decades have exempted agriculture from water discharge controls. Aside from making sure their topsoil didn’t wash away, most valley farmers haven’t had to worry much about what rolled off their fields.

That is about to change. Some, like Maring, are already starting to pay heed. Soon, thousands of other farmers may be following his lead--whether they want to or not.

Pressured by the Legislature, environmental lawsuits and mounting evidence of pesticide pollution, the state is poised to crack down on farm runoff, sending clouds of anxiety floating across the valley’s 7 million acres of irrigated cropland.

“It just makes you want to pull your hair out,” said Paul Wenger, a ruddy-faced almond grower, pesticide applicator and vice president of the California Farm Bureau Federation. Wenger worries that runoff controls will mean more paperwork and higher production costs--”with nothing out the other side.”

California farmers applied 170 million pounds of pesticides to crops in 2000. More than half of that was used on the fruit and nut trees and vegetable rows that make the Central Valley one of the nation’s most productive food factories.

When rain pounds the orchards in winter storms, pulses of dormant season pesticides roll with it into the river systems that feed the delta. When irrigation water runs off the slow-draining fields of the valley’s west side, the residue of summer sprays goes with it.

Rivers Full of Chemicals

Scientists for the Central Valley Regional Water Quality Control Board have been studying runoff for more than a decade, collecting and testing water samples. Researchers at the UC Davis aquatic toxicology lab and the U.S. Geological Survey have conducted similar surveys.

All have found pesticides. A federal study of the San Joaquin-Tulare river basins, for instance, reported as many as 22 different pesticides in a single water sample.

Concentrations of the chemicals are potent enough to kill aquatic life.

The findings prompted the state in 1998 to list hundreds of miles of Central Valley waterways and parts of the delta as violating clean water standards.

Included were sections of such rivers as the San Joaquin, Sacramento, Merced and Stanislaus, as well as the sloughs and drains that are the workhorses of the valley’s elaborate water grid. Late last year, the regional water board staff recommended declaring eight more pesticide-laden bodies of water in violation of clean water standards.

The problem extends beyond the boundaries of the huge Central Valley. “Almost any agricultural watershed we go into, we see the same thing,” said Victor de Vlaming, director of the UC Davis aquatic lab.

Two parallel currents are forcing action on the issue. When a waterway is listed as polluted, the Clean Water Act demands contaminants be reduced until water quality standards are met. Additionally, legislation passed in 1999 ended agriculture’s exemption from the state’s clean water law as of January 2003. Regional water quality boards could, in theory, renew the waiver, but environmental litigation and the pollution listing make it highly unlikely that a wholesale exemption from clean water standards will continue.

“[Agriculture is] being dragged kicking and screaming under the regulatory umbrella,” said Bill Jennings, whose Santa Claus-like appearance and folksy Tennessee accent belie the intensity with which his group, DeltaKeeper, has hammered the state to end the farm exemption. “They’re not happy about it. But I think the writing is on the wall. Essentially, they’re being asked to do the same things as municipalities, business and industry. They’re not being asked anything special.”

Indeed, a key researcher at the Central Valley water board said that if industry put into the state’s waters what farmers are, it would be ordered to stop. “It’s a double standard,” said Chris Foe, senior staff scientist at the board.

Surface Water Polluted

Pesticide pollution is hardly new--DDT contamination still lingers across the country decades after that insecticide was banned. Municipal drinking water wells up and down the Central Valley were contaminated by the soil fumigant DBCP before it was outlawed in the 1970s. And California rice farmers were forced to treat their field drainage after problems with herbicides in Sacramento Valley waterways arose in the 1980s.

But it is only in the last decade that evidence has emerged of more widespread surface water problems tied to pesticides.

As testing technology advances, scientists have been able to detect chemicals at lower concentrations. Government agencies are also taking a broader look at water quality, finding toxic levels of pesticides in both rural and urban surface waters.

“In the last decade or so, pesticides have been popping up,” said Kathleen Goforth, a scientist in the water division of the U.S. Environmental Protection Agency’s regional office. “It’s a combination of people never looking before and improved science.”

Water quality officials say they do not know what form a cleanup program will take. But it is likely the state will develop a system in which agriculture can continue to release irrigation and storm runoff while reducing contaminant loads. Steps might include water monitoring, timing of pesticide applications to avoid rain or irrigation cycles and construction of holding basins to trap the first flush of storm runoff, which is typically the most polluted.

“A lot of this stuff is really up in the air,” said Rudy Schnagl, chief of the agriculture unit for the Central Valley water board.

Agriculture is not exactly welcoming the scrutiny, which comes as the state is also preparing to bring Central Valley farmers under air pollution regulations they have long avoided.

De Vlaming says his UC Davis lab, which performs work for state regulatory agencies, has been accused by farmers of embarking on a pesticide witch hunt. Farming associations have criticized the toxicity testing methods and insisted that more water monitoring is needed. They argue that pesticide loads in Central Valley waters haven’t been shown to kill anything more than water fleas--one of the organisms commonly used in the laboratory toxicity tests.

Farmers also say their pesticide practices are constantly evolving and that if changes need to be made, they should be allowed to make them without more government regulation. “Everybody is trying to do the right thing,” said Wenger, who grows almonds and walnuts outside Modesto, where his family has farmed for nearly a century.

“We farm differently today than we did 20 years ago, 10 years ago,” he added. “Are the amount [of pesticides] they’re finding in waterways something that has been there for years and years? We’re cleaning up our act.”

Effects on Wildlife

Researchers acknowledge that it’s difficult to assess the impact of pesticide contamination on the broader range of organisms and wildlife found in Central Valley waters. But they say dead water fleas are like dead canaries in a mine shaft, a sign of trouble. “If you kill off water fleas, what are the fish going to eat? Everything is connected,” said the EPA’s Goforth.

Scientists also point out that little is known about what happens when a cocktail of pesticides is mixed together in field runoff. “We need to be very concerned about delayed effects we don’t see,” said De Vlaming.

“There are articles in the literature showing the interaction of pesticides--with one another or other substances--that make them a lot more toxic.”

Although some pesticide-laced waters are used for human consumption--delta waters supply more than 20 million people--regulators say they know of no public health problems in the state stemming from pesticides in surface water.

Trouble in the 1980s with herbicides in Sacramento’s water source led to improvements that could offer a model of sorts for the rest of the Central Valley’s contamination problems. The herbicides, carried into the Sacramento River from the area’s extensive rice fields, caused fish kills in drainage channels and left a metallic taste in river water.

The city sued the state, which then began requiring rice growers to hold water on their fields before releasing it. That allowed herbicide chemicals time to break down.

The rice industry, at first petrified at the requirements, now brags about the results, despite the price tag of about $25 million over 20 years.

“The rice growers are pretty proud now,” said Kati Buehler of the California Rice Commission. “They have a system that allows us to farm healthy rice and a system to keep pesticide residues out of water.”

No Quick Fix for Valley

What works in the rice fields may not work in the orchards and vegetable rows. “It’s not just a simple, one solution here,” said Art Baggett, chairman of the State Water Resources Control Board. “We’re talking about millions of acres of land with a very complex water system.”

Maring is already looking for the answer in his fields.

With the help of a grant from his local water district, he and a couple of neighbors are installing a system to capture some of the irrigation runoff from their sun-drenched cropland and pump it for reuse, rather than sending it off to the San Joaquin River.

“The progressive growers don’t have their heads in the sand,” Maring said. “They know this is coming.”