Irrigation season has come to a close in Central Oregon, and the canals that run through Bend and water the agricultural land in the region will be dry for the winter months.
But when irrigators start diverting water from the Deschutes River again in the spring, they'll be able to leave a little more in the river.
The Swalley Irrigation District, the Central Oregon Irrigation District and the Deschutes River Conservancy have replaced four side canals with more than 3 miles of pipes, reducing the amount of water that seeps through the rocks lining the canal.
Because of these water-saving measures, the irrigation districts can divert less water, and the resource can be returned to the river where it improves habitat and water quality in the Middle Des-chutes.
In addition, the Swalley Irrigation District, which stretches north of Bend, is gearing up to start an even bigger piping project on its main canal, which could return about 20 percent of the water the district uses to the river.
”The open canal is basically losing water to the ground, to the underlying soil, as the water travels through it,” said Scott McCaulou, program director with the Deschutes River Conservancy. ”Putting it in a pipe basically reduces the seepage lost to zero.”
Irrigators with water rights have been taking water from the Middle Deschutes below Bend for about a century, and the resulting loss of stream flow has had an impact on water quality as well as fish and wildlife habitat, he said. Less water means higher temperatures, which can be harmful for fish like the native redband trout.
The irrigators have had a ”gentleman's agreement” to leave a certain amount of water in the river, but the Deschutes River Conservancy has been working to conduct conservation projects and lease water for the river.
The organization recently bought the water rights for the water conserved from the four lateral canal projects, which total 6.6 cubic feet per second (cfs), or 810 million gallons over the course of an irrigation season from April through October. That's enough water to fill more than 1,200 Olympic-sized swimming pools, he estimated.
Over the last seven to eight years, the organization has worked to increase the summertime flow of that section of the river from 30 cfs to about 100 cfs. Most of that has been accomplished through temporary leasing agreements, as opposed to the permanent water rights the piping projects bring.
And another piping project scheduled to start in November should bring an additional 24 cfs of water to the Middle Deschutes, as the Swalley Irrigation District pipes 5 miles of the main canal in two phases.
In the first phase, contractors will dig up the canal for the 1.7 miles from Fort Thompson Road to the Bend city limit and replace it with a 48-inch pipe, said Jan Lee, the district's manager.
”It's nice to see it finally happening, because more and more subdivisions are being built by the canals,” Lee said. ”It's very difficult to be in people's backyard where we used to be in rural areas.”
Having an enclosed, underground pipe would eliminate the safety concerns of children falling into the fast-moving water of the canals, she said. It also pressurizes the water that the district delivers to farmers, which could save energy by eliminating the need to pump water.
The irrigation district is also planning to generate energy, Lee said. They are proposing to build a small, 1-megawatt hydropower facility with a turbine and generator that would turn the water flow into electricity. The power from the plant, scheduled to be built in spring 2008, would be sold to a utility, she said.
The idea for the main canal piping project started in 2000, with the city of Bend as a partner, she said. The city had planned to use credits from the water saved to acquire more groundwater rights, but the $9 million project ended up being funded by grants instead.
With the main canal piping project set to break ground before the end of November, Lee said she would like to pipe all 28 miles of Swalley's canals, ideally within the next five years if the funding is available.
Tod Heisler, executive director of the Deschutes River Conservancy, said the organization would support piping projects on the Swalley District as well as the other four districts in Central Oregon.
”Every irrigation district that's motivated to pipe canals, and wants to look to us as a partner to purchase conserved water, we're with them all the way,” Heisler said.
The cost of buying water rights varies depending on how old the rights are, and how likely they are to translate into actual water in the river, he said. But for a district like Swalley, with water rights dating back to 1899, the cost can be from $200,000 to $300,000 per cfs, he said.
The main hurdle in the way of the piping is finding funding for the projects, he said. He is looking at other ways of obtaining the money needed, such as getting loans and selling the water rights to conservation buyers such as Bonneville Power Administration, or marketing stream flow restoration to the general public, he said.
Once funding is available, ”we have plenty of irrigation districts who are lined up, ready to go,” he said.
One project is with the Tumalo Irrigation District, which has plans to conserve 20 cfs, and another is with the Central Oregon Irrigation District, Heisler said. In the end, he said, the Deschutes River Conservancy wants to work with all of the irrigation districts to pipe canals and return water to the Middle Deschutes.