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Farm Runoff: It's An Ongoing Challenge

By Gary Polakovic
The Press-Enterprise

® California water officials are seeking easy ways for farms to inexpensively clean up wastewater in the Salton Sea but no one is expecting a 'magic bullet.'

Irrigation practices that transformed California's scorched desert into one of the nation's most productive farming regions are the chief cause of pollution ruining the Salton Sea.

Growers who put food on the table dump waste water into the sea on a scale that would make big industries blush. Since the first drop of Colorado River water was diverted to make the desert bloom nearly a century ago, irrigated crop land spanning 600,000 acres in the Imperial and Coachella valleys has flushed a steady stream of salts, pesticides, fertilizers and selenium into the sea.

In the eyes of local farmers, the sea is first and foremost a waste dump. It is as vital to their fortunes as good markets and sunshine because its expansive shores swallow tainted water that if left on the fields would eventually saturate the soil with crop-killing minerals.

"The purpose of the sea is to receive agricultural drainage. That's what it's there for," said John Benson, a second-generation farmer who grows lettuce, cotton and cauliflower on 4,000 acres near Brawley.

Salton Sea area farms pour about 3 million tons of salt into the sea annually -- enough to fill about 40,000 railroad boxcars. The sea gets saltier each day, slowly killing fish and reducing the number of birds, fishermen and tourists that once flocked to it.

Farm wastewater pumps 50 pounds of selenium into the sea a year. Hazardous amount of the natural toxicant have been detected in silt, plants, insects, fish, birds and many living creatures in the sea and the maze of reedy canals that surrounds it.

Imperial County farmland is flooded to wash away salts and pesticides. Much of the polluted runoff drains into the Salton Sea.

Hundreds of miles of drains that funnel water from the farms to the sea contain elevated concentrations of pesticides washed from fields during irrigation. Fish kills in the drains are not uncommon. DDT has been linked to eggshell thinning in Salton Sea birds.

Yet, agricultural pollution goes largely unregulated in California and much of the nation. Clean Water Act requirements have cracked down on industries, sewer plants and other "point source" polluters for 20 years, but ignored farms until very recently.

"Agriculture is the number one non-point source pollution problem in this country," said Jovita Pajarillo of the U.S. Environmental Protection Agency's California office. "The agricultural industry has a very strong lobby. They are able to stave off a lot of regulations."

California agricultural interests last year successfully opposed a plan to require farms to pay fees to support a statewide pollution-tracking program for agricultural drains.

Farms that drain to the Salton Sea do not treat their waste water. Technologies are available to filter out many of the pollutants, but they are not employed.

The Firebaugh Canal Irrigation District uses a reverse osmosis treatment system to extract up to 80 percent of the selenium from tainted farm water near Mendota, west of Fresno.

But the technology is very costly. If employed in the Salton Sea area, It could cost about $1,000 an acre-foot of water -- an expenditure for dirty water about 90 times more than farmers pay for deliveries of clean Colorado river water. An acre-foot equals 326,000 gallons, the amount used by a household for five people in a year.

"It is an expensive process, but it can be done," said William Oswald, professor emeritus of environmental engineering and public health at the University of California, Berkeley.

For example, an inexpensive method called tail water recovery in use at a dozen Imperial County farms to capture and reuse water running off fields cuts pesticides and silt, but concentrates selenium in the agricultural drains.

Similarly, a $187,000 settling pond proposed near Holtville will eliminate pesticides from waste water, but may not stop selenium from reaching the sea. 

"It's kind of like you win one place, but lose somewhere else," said Phil Gruenberg, executive officer for the state Colorado River Basin Regional Water Quality Control Board.

This month, irrigation water suppliers must submit to state water officials a list of so-called best management practices showing how farms can cut their pollution. No one is expecting a magic bullet.

State water officials have done little to stop pollution. Some of their actions actually make it worse.

For example, the state Water Resources Control Board in 1988 mandated increased water conservation for Imperial County farms. But more efficient irrigation reduces fresh water flows to the sea, causing it to shrink faster, grow more saline and load more toxic selenium.

Critics, including the EPA and federal wildlife biologists, have scored the policy. The state water board has indicated it is willing to reconsider its position if petitioned to do so. But that has not happened.

Also, the state water board in 1991 exempted agricultural drains from attaining tough, new pollution standards contained in a management plan for land-locked water bodies in California.

Farmers were asked instead to voluntarily trim their pollution over six years or more. And they need only meet "performance goals," non-enforceable pollution targets more lax than what is required of other polluters.

Farmers argued, and state water officials agreed, they were entitled to flexibility since the drains were built to carry waste water, not to support wildlife or recreation. But the EPA disagreed, overturned those provisions in the state plan and will impose stringent federal standards for agricultural drains next month, said Maria Rea, chief of the water quality standards section for EPA's California office.

"I'll be the first to admit the progress made has not been satisfactory," Gruenberg said. "But it's not as if we're not doing anything. There are things being done and more is going to be done."

Agriculture has dominated the political and physical landscape of the Salton Sea area since the turn of the century.

A U.S. government geological team headed by William Blake was dispatched to the desert in 1853 to find railroad routes. Instead, Blake recognized the fertile soil in the ancient lake bed of what was then called the Salton Sink and wrote the whole region "may be considered as capable of supporting a luxuriant growth of vegetation, provided it is supplied with water by irrigation."

By 1901, farmers scraped out a channel for the Imperial Canal using horse-drawn plows. The Salton Sea did not even exist at that time, for the man-made accident that diverted the Colorado River into a sub-sea level depression to form the sea would come four years later.

TOP CROPS

The top 10 cash crops grown in the Coachella and Imperial valleys in 1991:

Grapes

$130 million

Alfalfa

$129 million

Lettuce

$109 million

Carrots

 $57.4 million

Dates

 $50 million

Cantaloupes

 $49.4 million

Sugar beets

 $46.4 million

Onions

 $46 million

Tomatoes

 $37 million

Lemons

 $30.5 million

The Press-Enterprise  

In 1928, farmers and the local irrigation authority completed the larder All-American canal, the lifeline connecting farms to the precious fresh water in the might river 60 miles to the east. Agricultural drains, which today crisscross the agricultural valleys and supply the sea with fresh, albeit polluted, water, came in 1929.

President Calvin Coolidge in 1924 and 1928 designated land at about 220 feet below sea level -- site of the current Salton Sea -- as an agricultural sump.

The Salton Sea National Wildlife Refuge was one of the last additions to the area in 1930.

Nineteenth-century pioneers called the area the Valley of the Dead. But it was Blake the geologist who correctly predicted the future.

Today, the Salton Sea area is an agricultural miracle. The bread basket called Coachella and Imperial valleys produces $1.1 billion worth of food each year -- the eight largest agricultural center in the nation.

About 85 percent of the nation's winter vegetable crop comes from farms in the sun-filled valleys that abut the sea like bookends at its north and south shores.

Land where once scorpions and rattlesnakes dared go now sprouts fields of melons, broccoli, asparagus, carrots and sugar beets. All accomplished in a region with 2.5 inches annual rainfall and temperatures at or above 100 degrees on third of the year.

Water, lots of it, drives this agricultural engine -- and the pollution.

The region's farms draw nearly 3 million acre-feet of Colorado River water annually -- accounting for half of California's draw on the Colorado River and more water than thirsty cities in the metropolitan Los Angeles and San Diego areas import.

But high evaporation loss due to extreme temperatures coupled with the chalky texture of Colorado River water spells trouble.

Every acre-foot of Colorado River water contains one tone of dissolved salts and minerals. The material is leached from rocks during the river's 1,400-mile journey from the Rocky Mountains.

Selenium, a sulfur-like element, comes from the Green River Valley in northern Utah, among other places where pockets of selenium-rich sedimentary soils prevail in the West.

Every time a crops is irrigated, the water evaporated in the withering desert heat, but the salts and selenium are left behind in the soil and start to accumulate in amounts that kill the roots of plants.

To protect their crops, farmers flush their fields with 15 percent more water than plants need, driving the pollutants about 8 feet deep into the ground and then out through underground drains.

A crop dusting plane makes a banked turn as it flies over a field in Imperial County

Photos by Steve Medd /The Press Enterprise

Drain water that runs off the top of the field contains pesticides while the water that comes from the bottom of the field is loaded with salts and selenium.

In some agriculture drains, selenium measures up to 60 times greater than the federal standard to protect aquatic life. An elaborate system of drains spanning 1,600 miles carries the pollutants to the New, Alamo and Whitewater rivers which empty in the Salton Sea.

Selenium pollution plagues agricultural regions throughout the western United States.

Four sites showed enough contamination to merit detailed investigations of pollution effects on plants and animals. The detailed study for the Salton Sea is expected to be released this year.


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