Piping project makes way for steelhead

An irrigation piping project currently underway by the Three Sisters Irrigation District (TSID) promises to be the final piece in a decades-old puzzle of how to restore salmon and steelhead runs to Whychus Creek.

The project will transform nearly four miles of the open and leaky principal irrigation diversion into a sealed, watertight pipeline.

Since the 19th century, local farms and ranches have diverted irrigation water from Whychus Creek (formerly Squaw Creek). At times, irrigation diversion was so extensive that the stream could go entirely dry. Faced with deteriorating stream conditions, the already struggling anadromous fish runs were completely extinguished in the 1960s by construction of dams on the lower Deschutes River.

The downward spiral of Whychus Creek stream quality has been reversed in recent years as Three Sisters Irrigation District, the Deschutes River Conservancy, the Deschutes Land Trust, the Upper Deschutes Watershed Council and others have made a concerted effort to restore a guaranteed water flow to the beleaguered stream.

At present, Whychus Creek itself is permanently "entitled" to a flow of more than 15 cubic feet of its own water per second (cfs). Historically, the creek supported strong anadromous runs of summer steelhead and spring chinook salmon. According to the Oregon Department of Fish & Wildlife, 14 to 20 cfs is the absolute minimum flow for maintenance of anadromous fish populations.

The current TSID project, however, will take the lowest guaranteed flow above the "minimum" range for perhaps the first time in a hundred years. That, coupled with the completion of the Pelton-Round Butte Dam fish passage system, could mean the return of anadromous fish runs in as little as two years.

TSID's current undertaking is actually a three-year project, but a key portion is scheduled to be completed before the irrigation season begins in April of this year. According to Marc Thalacker, TSID manager, nearly half of the leaky canal will be fully enclosed before the water starts to flow in April.

Before recent improvements, Thalacker said, roughly 55 percent of the Whychus Creek water that entered the irrigation system was lost to evaporation and leakage.

Thalacker expects that completion of the piping project will not only boost Whychus Creek flow above the 20 cfs level, but that it will provide substantially more water for TSID users, as well. Studies indicate that 10.8 cfs will be saved on this 3.77-mile piping project alone. Of that amount, 6 cfs will stay in the creek, and the balance will be a bonus for TSID users.

"If the farmers see an increased on-farm delivery of irrigation water, that will be a benefit," Thalacker said. "Over the last 10 years, TSID has been able to move from conflict to consensus, both within the district and outside."

He points out that, when complete in 2013, the project will include a hydroelectric system that will use the pipeline flow to generate between four and five million kilowatt hours per year.

"That's enough to power 500 Sisters homes," Thalacker said. "With the renewable green energy, the whole community will benefit. Ultimately, it's a win-win-win situation for everyone."

Right now, TSID is laying side-by-side 54-inch, high-density polyethylene pipes from the main irrigation canal diversion off Whychus Creek, under Three Creek Road, to just beyond Forest Road 4606 that follows the old railroad grade and leads to the back of the Sisters Rodeo Grounds. The twin pipe installation will allow better flow control and permit isolation and separate operation of the two hydroelectric turbines during periods of varying water flow.

The four-and-a-half-foot diameter pipe is delivered in 53-foot lengths that are "welded" together by an elaborate process that melts the surfaces to be joined and presses the pipe ends together. Thalacker said that the resulting joints are stronger than the pipe itself. Ten-piece pipeline segments are then machine-dragged, like enormous garden hoses, to their final positions along the existing diversion canal.

More pipe for the remainder of the project will be laid after the irrigation season ends in the fall of this year. At that time, construction will also begin on an elaborate - "and enormous" - water diversion and fish screening device that is longer than a football field.

The fish screen itself will be approximately 140 feet in length and horizontally aligned so the water flows parallel to and over the top of the screen. Fish entering the irrigation diversion will pass over the screening system and be returned to the creek downstream of the dam through a separate pipe. The openings in the screen will be small enough to exclude even the smallest fish fry.

Thalacker says that half of TSID's 60 miles of canals are already enclosed in pipe, and he expects that the entire district will be piped within the next ten years. Planning for the downstream piping from the TSID reservoirs is already underway.

The hydroelectric turbines are scheduled to be completed in April 2013. When they come online, Thalacker says that "13 percent of Central Oregon's electricity will come from small-conduit in-line renewable hydroelectric power."

The project has been, and continues to be, a rewarding one for Thalacker.

"I enjoy this very much," he said. "There are very few natural resource and environmental projects where you can bring benefits to fish, farms, and the entire community."

Thalacker is proud of the employment opportunities that the TSID project is providing to the area. He also noted that local businesses are seeing trickle-down economic benefits from the project.

The completion of the piping project and the fish screening system is timed to coincide with the earliest possible return of anadromous fish through the Deschutes River system. Chinook salmon and steelhead fry have already been reintroduced into Whychus Creek, and some have been observed making their way to the sea by successfully negotiating the new fish passage system at the dams on the lower Deschutes River.

"If the fish flourish and thrive," said Thalacker, "that will be the true test of the anadromous fish reintroduction experiment."