Multiple users challenge irrigators now and into the future

By Larry Dreiling

"Whiskey is for drinking; water is for fighting over," Mark Twain supposedly said.

One of the early tributaries of the Mississippi River that Twain so eloquently wrote about is being fought over by farmers and urban interests close by as well as far away from their source.

Last summer, Colorado State Engineer Hal Simpson ordered the pumps of about 400 wells turned off after the producers failed to prove in water court they could replace their groundwater withdrawals.

The producers, operating about 300,000 acres in Weld, Adams, Arapahoe and Elbert counties, claim that their pumping doesn't harm the river because they are tapping an underground aquifer that has very little connection to the surface water.

The producers, seeking to form the Box Elder Creek Designated Ground Water Basin, have failed to prove so far, to the satisfaction of the Colorado Ground Water Commission, that their use of groundwater isn't linked to reduced return flows. The producers claim that their pumps, many as far as 60 miles away from the river, pump water from an aquifer and not directly from the river.

There are several ditch companies, cities and major water providers, however, lining up to fight the proposed basin designation, saying the irrigators pump about 20,000 acre feet annually from the river. Cities included in the fight look like a map of the South Platte itself, with Denver, Aurora, Greeley and Sterling in opposition to the designation.

"Complicated

and complex"

The thirsty population of the East Slope of Colorado, Simpson said, is expected to climb by 2.4 million people between 2000 and 2030, placing further pressure on agriculture, with, by some estimates, a potential decrease in irrigated acres along the South Platte rated as low as 133,000 acres to as much as 226,000 acres.

"It's complicated and it's complex. I could stop right there," Simpson said in a recent speech about water issues. At the heart of the issue is the concept of return flow, or water having been diverted from a water body, usually for irrigation, that is not consumed in the process and flows back to the original or some other body of water.

The Platte River is actually comprised of three rivers connecting into two more rivers. The North Platte, from its headwaters in Jackson County, Colo., stretches 618 miles. The South Platte, from its headwaters in Park County, Colo., is 424 miles long.

At the confluence of the two rivers, at North Platte, Neb., the river traverses the Cornhusker State for another 310 miles to its confluence with the Missouri River at Omaha and finally merging with the Mississippi River at St. Louis, Mo.

Because the South Platte is in essence a major tributary of America's major river, with an historic annual stream flow of 403,400 acre feet of water, Simpson said every state whose waters flow eastward are affected by waters far away, and that includes the South Platte. Because of this, Colorado entered into a compact with Nebraska in 1923 based on an 1890 water right at the border of the two states.

The South Platte River basin covered about 1.003 million acres in 2000 with about 2.545 million acre feet of gross agricultural diversions, according to Dr. Reagan Waskom, director of the Colorado Water Resources Research Institute at Colorado State University. That's the equivalent of 2.54 acre feet of water per acre used for irrigation.

Simpson said return flows are critical to the life of a river. Ground water pumping reduces the stake of return flows that rights holders all along the river must share.

"The maintenance return flows that target any change in water rights that complicates the ability to use water to its most efficient use," Simpson said.

Because of that, proper administration of ground water management is tied to compliance with the compact.

"We are in compliance with the compact. We will stay in compliance if we augment the use of the water properly," Simpson said. "Nebraska is starting to ask questions about 'how do you know your augmentation is working. We want more information that you are doing the right thing.'"

Simpson also said the state has hired a consultant to evaluate its ground water administration and signed a recovery agreement along with Nebraska, Wyoming and the federal government to take surplus loads of water back to the river at certain times of the year to assist Nebraska with water for migratory fowl.

Solutions studied

Gov. Bill Ritter, D-CO, was just sworn into office in January. One of the first major meetings he held was the Colorado Water Congress. It examined four long-term solutions for water management:

--Ag and urban water conservation;

--Increased water reuse;

--Water sharing agreements between cities and farmers, and;

--As a last option, build more reservoirs and storage projects, particularly on the Front Range.

Waskom, for his part, said there is a host of concepts to address Ritter's first point on ag water conservation. Conversion of flood irrigation to gated pipe, surge, sprinkler and drip has an increasingly higher level of irrigation efficiency.

"The typical efficiency of flood irrigation is between 25 and 50 percent," Waskom said. "Furrows are 25 to 60 percent, a big gun is 50 to 75 percent; side rolls are 60 to 85 percent efficient, a center pivot is from 70 to 85 percent. Drip irrigation is 75 to 95 percent efficient."

Besides the method of distribution, Waskom said there are many other ways to save water.

"Ditch lining, lower water use cropping systems, limited irrigation, water metering, irrigation scheduling, alternate row irrigation, tail water recovery and polyacrylamide use in ditches and furrows all can work," Waskom said.

"The question remains, can irrigation water conservation alone solve the problem?"

Think efficiency, too

That's why Waskom said producers might want to think about water efficiency along with conservation. Those efficiencies can be found many different ways.

"The way you measure water use efficiency is the ratio of water applied compared to water consumed by ET, evapotranspiration," Waskom said. "Water that is conserved through more efficient diversion and application methods is called saved water. Water that is conserved from a nonbeneficial loss of water diverted under a valid water right is called salvaged water."

There's also reduced consumptive water use, Waskom said. It occurs when producers reduce their acres, switch to cool season crops or switch to crops with a shorter growing season.

Alfalfa, as measured at a test plot at Wray, Colo., takes about 35 inches of water to produce a crop over 204 days. Grain sorghum, meanwhile, requires about 16 inches in a 92-day growing period to produce a crop.

"These are things we have to consider," Waskom said.

More questions

There are other questions Waskom thinks will have to be answered by anyone who uses or cares about water and agriculture:

--Are additional policy alternatives needed to address ag water movement?

--Can increased irrigation efficiency or reduced crop consumptive use help maintain irrigated acreage?

--Can increased storage help maintain irrigated agriculture?

--How will urban conservation and reuse impact agriculture?

--Are there priority-irrigated areas in Colorado that should be targeted for preservation?

"The biggest question of all is how will the loss of 250,000 to 400,000 irrigated acres in the next 25 years change Colorado and agriculture?"

A hearing officer for the ground water commission Feb. 20 ruled against the proponents of the designation ground water basin. The full commission is expected to rule on the hearing officer's recommendation at a May 18 hearing. Meanwhile, proponents of the designation have been quoted in the local media that the fight isn't over yet.

"We have a lot of competition and lack of cooperation on the South Platte River basin," Simpson said. "Leadership and cooperation is needed more than ever."

Larry Dreiling can be reached by phone at 785-628-1117 or by e-mail at ldreiling@aol.com.

A

1

4/2/07

None

Date: 3/29/07

	Web hpj.com

Copyright/Privacy
Copyright 1995-2008.  High Plains Publishers, Inc.  All rights reserved.  Any republishing of these pages, including electronic reproduction of the editorial archives or classified advertising, is strictly prohibited. If you have questions or comments you can reach us at High Plains Journal 1500 E. Wyatt Earp Blvd., P.O. Box 760, Dodge City, KS 67801 or call 1-800-452-7171. Email: webmaster@hpj.com