Learning to Manage a Very Salty River

Flowing through the heart of agricultural issues in southeast Colorado is a very salty river.

Jim Valliant, regional irrigation specialist for Colorado State University Extension in the Arkansas River Basin, frequently looks to history to understand the problems--present and potential--facing farmers who rely on the Arkansas River for water.

"The Arkansas River is one of the most saline rivers in the United States, especially for its size," Valliant explains. "Where the mountains meet the plains, it measures 500 parts per million dissolved solids, which is a measure of salinity. It has been recorded as high as 5,100 parts per million at Coolidge, Kan., a measuring point just east of the Kansas-Colorado border," Valliant said.

At least part of the problem has been traced to traditional irrigation practices, which divert the already salty water over salty soils. The water picks up salt and carries it back to the river. Meanwhile, salty soils grow saltier, reducing yields, raising farming costs and lowering returns.

Valliant reaches back millions of years to explain the problem's roots: "The source, of course, is that we used to be the bottom of an ocean and the sea collected here." The salt remained after the mountains rose and the seas drained away. Over the years the river, and the run-off waters that feed it, have collected salt from the former ocean bottom. An estimated 75 percent to 85 percent of the salt in the river is contributed when rainwater flows over rangeland and down to the river. "It's a naturally occurring thing. The problem is we concentrate it on the irrigated land."

Human manipulation of the river waters has served to increase the naturally occurring saline levels, Valliant said. Irrigation, reservoirs and growth and development all play a role.

He reaches back into history again to point out why it matters--intensive agriculture and excessive irrigation have contributed to the demise of past civilizations. The ancient Mayans, Romans and Mesopotamians all built elaborate irrigation systems. In the overpopulation and drought problems that contributed to their downfalls, Valliant sees ominous reminders.

Valliant has devoted much of the past 10 years to finding and demonstrating new irrigation practices and technology to help stem the salty tide in the Arkansas River Basin.

"I've had as many as 21 demonstrations over the area. We've demonstrated surge irrigation, the use of polyacrylimides to reduce erosion and enhance water absorption, and reduced tillage procedures," Valliant said, ticking off a few.

Like the water that flows from ditch to ditch, the information gleaned from these on-farm demonstration projects flows from farmer to farmer. "The good thing is the person who did the work is down at the coffee shop talking to neighbors and therefore it spreads."

Farm practices seem to be changing, said Lorenz Sutherland, area agronomist for the Natural Resources Conservation Service. He observes change particularly among farmers most likely to adopt new techniques and technologies. "Jim has done an outstanding job in working with those early adopters. Before Jim came along, there was no one using polyacrylimides. Now, there are quite a few."

Polyacrylimides are added to the soil to increase water absorption and reduce soil erosion during irrigation. This helps farmers cut costs through more efficient irrigation while reducing the amount of sediment and salt that is returned to the river.

Scientists are convinced that the kinds of irrigation and farm management practices that Valliant has been demonstrating and discussing in the Arkansas River Basin are benefiting the river, Sutherland said. But the enormous size of the watershed makes it difficult to measure an actual change.

"It's really difficult to tell," he said. "When you're dealing with a very, very large watershed with somewhere around 25,000 square miles, a burp in the upper part of the watershed--a big rainstorm in some cases--can have more affect than anything we may do on farms."

Valliant's work has raised awareness of the necessity and benefits of efficient irrigation, said farmer Cliff Walter. Walter partners with his wife and two sons in a general farming operation in Crowley County near Manzanola. The Walters produce alfalfa, corn, onions, watermelon and cantaloupe on about 3,000 acres and run a 125-head cow-calf operation on another 1,000 acres. The Walters must focus on efficient water use in the face of decreasing water supplies.

In Crowley County, much of the surface irrigation water has long since been sold to thirsty Front Range cities, Walter said. "As less and less water is available, then the kind of things Jim has been working on will come in to play and be more and more important."

Walter said he appreciates the volume of information that Valliant and other CSU researchers produce. "That's where they do a real good job is everything that they're working on is documented" and published in newsletters, magazines and local newspapers.

"Jim has always been very progressive in his ideas," Walter said. "He has done very well in research with water management and grass seeding, and just new ideas. So we've tried to work with him very closely and have benefited quite a lot with what we've learned."

--Sue Lenthe

For more information, contact your local Colorado State University Extension office.

Go to top of this page.

Uploaded Wednesday, July 09, 2008 Error processing SSI file