This article was published on: 01/13/14 12:00 AM
Mirror Pond dam could soon be only structure without passage
By Hillary Borrud
Plans to build fish passage on two dams in Bend mean that within the next five years, the Mirror Pond dam will likely be the only man-made structure still blocking the path of fish on the Middle Deschutes River.
The Bend Park & Recreation District plans to build fish passage into its Colorado Avenue dam project, which will also make it possible for whitewater kayakers and people on inner tubes to pass over the dam.
The district currently expects to complete that project by June 2015.
Meanwhile, three irrigation districts and the Oregon Department of Fish and Wildlife have nearly completed the design for a fish ladder on the North Canal dam on the Deschutes River near Northeast Division Street.
“If we had fish passage on the dams in the Bend vicinity, we would have fish passage at all the human-caused barriers from Billy Chinook to Wickiup and that would enable fish to freely migrate seasonally up and down the river to seek out favorable habitat at different times of the year, and that’s our primary goal,” said Brett Hodgson, district fish biologist for ODFW in Bend. “While you may view passage at Mirror Pond as being of limited value because of the other dams, the fact that we are making progress toward getting fish passage on the other two really puts it in a different perspective.”
Local officials have said if ownership is transferred to a new entity, the state might require the owners of Mirror Pond dam to build fish passage on the structure. Hodgson said repairs or modifications to 30 percent of any dam would also trigger the requirement in state law for fish passage.
PacifiCorp discovered a leak in the dam in October and subsequently announced that it plans to decommission the dam or transfer ownership to another entity. A local committee tasked with deciding the future of the dam and the portion of river behind it wants to keep the dam. But city councilors and Bend Park & Recreation District officials have said they do not currently have the money to pay for acquisition and repairs to the dam or dredging silt from the river.
The state also has criteria for fish habitat that would apply if PacifiCorp removes the dam. “The site would have to be returned to a condition that met our fish passage criteria,” Hodgson said.
The Middle Deschutes River refers to the stretch of river from Wickiup Reservoir down to Lake Billy Chinook. In the Bend area, the Deschutes River is home to native redband trout and mountain white fish and non-native brown trout. “Seasonally, there’s different flow patterns; water temperature changes seasonally and it’s important for fish to be able to move within the river to seek out those areas that are more favorable,” Hodgson said.
The state has designated redband trout as a sensitive species and although ODFW allows anglers to keep some, the agency manages the number harvested with the goal of conservation, he said. “It does not afford them any particular legal protection,” Hodgson said.
New fish passage structures will help the trout species that already live in the area, but they will not result in any new species migrating to the area on their own because large waterfalls downstream prevent those fish from reaching Bend. “The downstream natural barriers would likely prevent salmon and steelhead that are being reintroduced into the Lower Deschutes (River) from making it upwards into the vicinity of Bend,” Hodgson said.
Big Falls near Terrebonne has historically stopped salmon and steelhead from swimming farther upstream, and Hodgson said ODFW has no plans to introduce those fish upstream of the falls. Bull trout historically lived in the Middle Deschutes, but “they were able to colonize the upper Deschutes basin back when conditions were considerably different than they are now,” Hodgson said. “They can’t come back on their own. There would have to be a reintroduction effort.”
Hodgson said the decision on whether to reintroduce bull trout lies with the U.S. Fish and Wildlife Service, and the agency has not announced any intention to do so.
North Canal dam
Hodgson said the plan is to build the fish ladder on North Canal dam within the next few years. “I think it’s both ODFW’s desire and the irrigation districts’ to have passage there within five years,” Hodgson said.
Steve Johnson, manager of the Central Oregon Irrigation District, said the estimated cost of the project has increased. “Originally, we thought the ladder was going to be $1 million,” Johnson said. “Now, it looks like between $1.2 and $1.4 million.”
The three irrigation districts — Central Oregon Irrigation District, Swalley Irrigation District and North Unit Irrigation District — signed a voluntary agreement with ODFW in order to obtain water rights to begin operating hydropower facilities with the water they already had rights to use for irrigation, Johnson said. The irrigation districts’ hydroelectric facilities are not at the dam. “They’re actually in the irrigation canals a ways away from the dam itself,” Hodgson said. “When they put in hydro facilities on their canals, that was a trigger for our fish passage statute to provide fish passage facilities at the pre-existing site.”
The districts agreed to pay 40 percent of the cost for fish passage, and have for three years been putting money into an account to pay for the project. The state has not yet identified how it will come up with its share — at least $600,000 — that is necessary to build the ladder.
Johnson said there is not a deadline to finish the project, but he hopes ODFW can find the money soon to complete it. “If you don’t get this built, the people who helped put this together, they all retire or go off somewhere (else) to work, and you lose history of why something was done,” Johnson said. “The longer it takes to get something done, the more difficult it’s going to be to get it done.”
ODFW is vague on where it might obtain the money. Hodgson said only that the agency is exploring its options.
The irrigation districts and ODFW began working on a design for the ladder in 2013, and they are now working on final details, Hodgson said. Johnson said the irrigation districts and ODFW are still adjusting the fish ladder design to make it as economical as possible. The metal fish ladder will cost less than a traditional concrete structure, Hodgson said.
Colorado Avenue dam
Chelsea Schneider, a landscape architect for the Bend Park & Recreation District, said the agency is still working on the design for the Colorado Avenue dam project. Consultants will meet with parks employees on Monday and Tuesday to finalize some of the details. The current plan is for fish and people on inner tubes to use the same channel to move over the dam. The park district is paying for the $7 million project with money from a bond measure voters approved in 2012, as well as with funds raised by the Bend Paddle Trail Alliance.
“Basically the fish passage will be concurrent with the safe passage channel, so the velocities that we’ve achieved with the design make it slow enough and long enough, the drops are shallow enough that fish can migrate upstream,” Schneider said.
The Colorado Avenue dam already has a fish ladder, but Schneider said ODFW has not observed evidence that fish use the existing passage. “This proposal would be more beneficial to fish, in that smaller fish will be able to pass up it and they’ll have refuge in the eddies and it’s more fully designed for that purpose,” Schneider said.
— Reporter: 541-617-7829, hborrud@bendbulletin.com