From the Grand Junction Free Press (Hannah Holm):
Driving east on Interstate 70 though De Beque Canyon, it’s hard to miss the elegant towers and arches of the Grand Valley Diversion Dam, also known as the Roller Dam, which will turn 100 next year. Its red tile roofs stand out amid the dusty tans and greens of the canyon, and the river becomes a broken line of waterfalls as it flows over or under the dam’s roller gates, depending on how much water is being diverted.
I recently saw the dam up close on a tour of the canal system operated by the Grand Valley Water Users Association. The association took over operation of the Roller Dam and the Government Highline Canal from the U.S. Bureau of Reclamation, which built the system.
Our little group marveled at the massive gears and chains that move the roller gates, and also learned about features of the system that are less obvious. Just past the historic dam, canal water flows through a pair of much newer screens. Fish and small sticks are shunted back into the river, but bigger items, including small trees and the occasional bear carcass, is hauled out with an excavator.
A few miles downstream, a small octagonal building marks the start of the Orchard Mesa Siphon, which carries a share of the canal’s water underneath the Colorado River and I-70 to the Orchard Mesa Power Canal. I drove right below the concrete wall edging the canal for years without realizing that up to 800 cubic feet per second was flowing above me on its way to a hydroelectric plant and pumping station just south of Palisade.
This hydraulic pumping station lifts water uphill to the Orchard Mesa Irrigation District’s 30-plus miles of canals, serving orchards, vineyards, vegetable plots and subdivisions on the south side of the river. The water that runs through the hydroelectric plant can either return directly to the river or run through a short canal that ends just upstream from the Grand Valley Irrigation Company’s diversion on the other side of the river, facilitating the sharing of water between the two systems.
Beyond the Orchard Mesa Siphon, the Government Highline Canal continues West through a 7,486-foot-long tunnel, which ends at the Price-Stub Pumping Plant near Palisade. Here, water is lifted into the canals of the Palisade Irrigation District and the Mesa County Irrigation District. These two systems pre-date the Government Highline Canal, but the Roller Dam now diverts their water because it made their original diversions from the river inoperable.
As the Government Highline Canal continues west beyond Palisade, orchards and vineyards give way to larger acreages growing corn, alfalfa and other row crops. The Grand Valley Water Users Association uses the 55-mile-long canal to deliver irrigation water to 23,340 acres of land.
In recent years, major upgrades to this historic system have benefited both the health of the river and the irrigators that rely on it for their livelihoods. In order to reduce the amount of water needed to carry irrigation water to the end of the system, checks were placed in the canal. These can raise water levels high enough to reach headgates without requiring the canal to be running full. Farmers still get their water, and more water is left in the river to benefit endangered fish. The checks also allow the canal to remain operational when there is less water in the river to start with.
The checks were paid for with funding from the Upper Colorado River Endangered Fish Recovery Program, which in turn gets its funding from the sale of hydropower from Glen Canyon Dam.
The lining and piping of canals and ditches has reduced seepage, and with it, the leaching of salt and selenium into the Colorado River. This benefits both downstream farmers and endangered fish, and it has been largely paid for with federal funds.
When the Government Highline Canal was completed in 1917, it marked the final stage of the development of Grand Valley desert lands into productive crop land. It did not, however, mark the end of the development of the irrigation system, which continues to evolve in order to maintain its historic mission and meet new demands.
This is part of a series of articles coordinated by the Water Center at Colorado Mesa University in cooperation with the Colorado and Gunnison Basin Roundtables to raise awareness about water needs, uses and policies in our region. To learn more about the basin roundtables and statewide water planning, and to let the roundtables know what you think, go to http://www.coloradomesa.edu/WaterCenter. You can also find the Water Center on Facebook at http://Facebook.com/WaterCenter.CMU or Twitter at http://Twitter.com/WaterCenterCMU.
More Colorado River Basin coverage here.