WIMER — The 100-year-old Wimer Dam that spans Evans Creek near this community is a classic example of a structure doing far more harm than good to the wild salmon and steelhead that call the creek home.
The 8-foot concrete dam was abandoned as an irrigation diversion more than three decades ago, but it still blocks upstream fish passage. Its antiquated fish ladder, cobbled together by volunteers in 1980, works only under the best of conditions for salmon and steelhead trying to get to miles of prime spawning habitat upstream of it.
"It's a typical story for a partial barrier," says Dan VanDyke, the Oregon Department of Fish and Wildlife's Rogue District fish biologist. "There are times fish can pass it and other times when they can't pass it at all."
That's why the Wimer Dam, and the smaller Fielder Dam six miles down Evans Creek, have the dubious distinction of being listed as two of the 10 worst impediments to fish passage in Oregon.
They join such fish-busting powerhouses as the Snake River's Hell's Canyon Dam and the North Santiam's Detroit Reservoir on the state's new prioritized list of 534 dams, culverts or other fish-passage blockages state biologists would like to see fixed or removed.
Fielder and Wimer dams are the only Rogue River Basin structures to make the new top 10 category, which does not include specific 1-through-10 rankings.
"They're both abandoned, so they really should come out," VanDyke says.
Created during a two-year effort by the ODFW, the list will be presented Friday in Salem to the Oregon Fish and Wildlife Commission for adoption.
Oregon has more than 27,800 documented artificial obstructions to fish passage. More than 23,000 of those do not provide an adequate way for native fish to make it past them, according to the document.
The ODFW is required by state law to identify and prioritize the barriers and the law requires the list to be updated every five years.
The list helps the agency as well as dam owners and watershed councils decide when and where to choose for projects such as screening diversions, modifying, or removing dams and rebuilding culverts. It also can help dam and culvert owners gain grants from sources such as American Rivers and the Oregon Watershed Enhancement Board.
Also, state law allows the ODFW to require dam owners to complete fish-passage work on a Top 10 priority barrier as long as the ODFW secures at least 60 percent of the funding for it.
The rankings were created with a computer formula that takes into account the numbers and different types of native fish that are blocked by the structure, how much habitat is blocked, and the quality of the habitat.
Also taken into account are whether there are other main blockages upstream or downstream of the structure, as well as how well the current screens, ladders or culverts allow fish passage, and whether the structure blocked the migration of a species protected as threatened or endangered under the federal Endangered Species Act.
Those various factors dropped that Fielder and Wimer dams into the dregs of the group.
Each structure impedes fall chinook, coho, summer and winter steelhead, Pacific lamprey, suckers and cutthroat trout, according to the list. Wild coho in the Rogue Basin are listed as threatened under the federal ESA.
Fielder Dam, near Fielder Creek, was built in 1945 and has been abandoned for decades. It's owner listed in the ODFW document is Steve Keeton, who did not return telephone calls for comment.
Wimer Dam is listed simply as "private" with no stated ownership.
Rocky Wardle of Rogue River says he owned the dam in the late 1970s when he bought it and water rights from the failed Vroman Ditch District with hopes of creating a small hydropower plant. But the dream never came to fruition and he gave up ownership years ago, Wardle says.
Wardle disputes VanDyke's and the state's assertion that the dam severely harms fish passage. He also says it would work much better if the ODFW would keep the ladder debris-free for proper passage.
"It just needs maintaining," Wardle says. "They could blow it up and that would be fine, too. "It's just sat there all these years," he says.
The 534 total structures that made the problem list are clumped into 17 different categories of severity, with the least troublesome categorized as "other."
Pomeroy Dam on the Illinois River and Murphy Dam on the Applegate River rated in the category just beneath the Top 10. At the bottom of the list, an unnamed culvert on Anderson Creek is the only one to make the "other" category.
More than half of the structures on the list are dams, and slightly more than a third are culverts. The rest are tide gates, fords, bridges and similar structures.
The 2007 list included Gold Ray Dam as a Top 10 priority, and it was removed from the Rogue in 2010. Four of the 2007 Top 10 were fixed or removed in the past five years, and the six that remain on that list did not make the new Top 10 list, which was compiled under different criteria, the list narrative states.
Reach reporter Mark Freeman at 541-776-4470, or email at firstname.lastname@example.org.