Hydropower used to replace flood irrigation and to lessen ag runoff and salinity

nd now come new efforts across Colorado to further yoke the power of falling water. One such example is near Yampa, a town between Vail and Steamboat Springs. The site is just a few miles from where the Bear River takes a sharp turn and becomes the Yampa River. On his ranch, Gary Clyncke decided three years ago to use the 126-foot drop in elevation of his irrigation water to power a new center-pivot irrigation system.

Clyncke's hydro-mechanical center-pivot doesn't produce electricity. It does, however, preclude the need for stringing up power lines to operate the center-pivot sprinklers. The sprinkling system, in turn, saves water — which is worth money. The 90 acres were previously irrigated with flood irrigation from ditches spread across the field of timothy, brome and clover several inches thick. Center-pivot irrigation requires just one-sixth the water.

That savings motivated Clyncke to invest in center-pivot. This hydro-mechanical system cost $13,000, of which $6,000 came from the Natural Resources Conservation Service, a federal agency. That left Clyncke a cost of $7,000. Payback on that investment is achieved in three years.

Federal aid is motivation, at least in part, because of concerns about salinity. When large volumes of water are applied to fields in flood irrigation, the water picks up salts that are then returned to creeks and then rivers. It's a major problem on the Western Slope, where water can be used two times for flood irrigation before it enters Utah. Downstream in California's Imperial Valley, an important source of food for the nation, some fields have become so salty they have been abandoned.

One of the most saline areas is in the Uncompahgre Valley, where Delta, Montrose and Paonia are located. An ancient sea left salts and the element of selenium in unusually large quantities in the Mancos shale. Both are harmful to endangered fish downstream in the Colorado River. "Anything that you can do that helps with salinity also helps with selenium, and vice versa," says "Dev" Carey, manager of the Delta Conservation District.

Saving money is a strong argument by itself. Farmers spend an average of $33,000 each year on electricity, more than half of that to power irrigation pumps, according to the Colorado Energy Office. Using hydropower to operate these pumps doesn't work everywhere. Farms near Sterling, for example, tend toward flatness. Still, the state agency estimates Colorado has untapped capacity in pressurized irrigation systems to deliver 30 megawatts in direct production of electricity or avoided electricity. To put that into context, it's enough electricity for 12,125 homes, says Kurt Johnson, president of the Colorado Small Hydro Association.

More potential exists in irrigation ditches. Not just any irrigation ditch will do. It must have flows of more than 100 cubic feet per second, a relatively large volume. And there must be drops of at least 150 feet. When falls of that steepness occur, various devices are used to contain the force.

One such canal is located east of Montrose, where water from the Gunnison River is diverted through a tunnel that emerges near U.S. Highway 50. From there, the water flows through South Canal toward the head of the Uncompahgre Valley. In 2012, the Delta-Montrose Electric Association completed a project that had been talked about for more than 100 years. The two powerhouses generate electricity equal to what is needed for 3,000 homes.

In nearby Delta County, the state has identified nine sites on irrigation ditches where it would be economical to install small hydro systems, collectively producing 0.8 megawatts. That's given current prices of electricity. Should electricity prices go up, as they have steadily, more potential would exist near Delta and many other locations.

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Taxonomy

• Stormwater
• Hydropower
• Energy Efficiency