Umpqua Watersheds Blog

News, Restoration

THE WINCHESTER DAM A Slow-Motion Ecological Disaster

Published September 10th, 2023 in News, Restoration

by Ken Carloni

The Winchester Dam has degraded the fish runs and aquatic habitats of the North Umpqua River for over a century. It is currently undergoing repairs that will not improve access to the upper North Umpqua River by salmon and steelhead. The state and federal agencies that regulate dams, fisheries, water rights, and water quality all failed for decades to use their authority to require the dam owners, the Winchester Water Control District (WWCD), to bring the dam and its antiquated fish ladder up to current standards. The latest repair continues this lax enforcement: the dam owners were permitted to use the least expensive methods possible for the repairs, which involved drawing down the reservoir. This also drains the fish ladder, blocking access to critical habitat during the migration of imperiled summer steelhead, spring chinook and coho salmon and decimating lamprey larvae in the reservoir pool.

Winchester Dam Construction, Aug. 17, 2023. Photo by the author.

Work on the dam closed the fish ladder on Aug. 7th and was supposed to be completed by Aug. 28th. The WWCD could not complete the work on time, so the owners have predictably been granted an extension until Aug. 31th. As I write, migrating salmon and steelhead continue to be blocked from their natal streams as the reservoir refills.

The Winchester Dam is a derelict structure originally built 4 feet high in 1890 to run a lumber and grist mill. Using wood crib with cobble fill construction, the dam height was later raised to its current 17 feet in the early-1900s as a hydropower facility. A fish ladder was installed in 1945 to improve passage for migrating fish, and counts began the next year. After PacifiCorp discontinued generating hydro power at the dam in 1969, ownership was transferred to the WWCD who now maintains the dam solely to provide a private water ski lake for approximately 120 landowners surrounding the reservoir. Dams are allowed in Oregon ONLY for power generation or irrigation, but the Winchester Dam is “grandfathered in” because it predates those rules.

According to the Oregon Department of Fish and Wildlife (ODF&W), the Winchester Dam impedes access to 160 miles of high-quality habitat for salmon and steelhead, and is one of the state’s highest priorities for fish passage correction. Closing the ladder has now completely trapped those fish in the warm water below the dam with no cold-water refuges nearby. Ironically, rising temperatures earlier in the summer and rapidly diminishing summer steelhead numbers had compelled the ODF&W to shut down all angling in the North Umpqua from August through November. It is incomprehensible that the ODF&W is one of the agencies that signed off on a plan that completely blocks access to 160 miles of high-quality steelhead habitat during a critical time for the survival of this iconic run.

Umpqua Watersheds is a member of a coalition that includes WaterWatch of Oregon, the Native Fish Society, the North Umpqua Foundation, the Steamboaters, Pacific Rivers, and the Conservation Angler, and we’ve been working for years to raise concerns with agency and government officials over the WWCD’s chronic non-compliance with state and federal repair permitting, engineering, water quality, and dam safety requirements, and calling out WWCD’s apparent disregard for protections for fish and wildlife despite the essential habitat importance of the North Umpqua for salmon and steelhead.


The coalition has pointed out serious ecological problems that should have been addressed by the dam owners before permit should have been issued including:

Blocking Upriver Spawning Habitat: First and foremost, the poorly functioning fish ladder was constructed with a number of tight jumps, right-angle turns and little ability to control flow velocities, making it difficult for fish to navigate it under a wide range of flows. The ladder is also on the north side of the dam while the main flow of the river is toward the south. As a consequence of the “false attraction” of the main current, migrating fish spend a significant amount of time and energy jumping against the dam before they finally find the weaker flow that takes them to the ladder. An Oregon Dept. of Fish and Wildlife official is quoted as saying “It’s passing fish. But again, we also recognize that the dam is delaying migration. And that was one of the major reasons for moving it up on that statewide priority list [to improve fish passage]”. The ONE THING in the WWCD proposal that would have made a minimal improvement is fixing the leaks in the dam footing that were creating attractive flows causing injury to fish on sharp concrete and rebar. Unfortunately, photos taken as the reservoir refills show water continuing to leak under the dam.

Winchester fish ladder. Note sharp right angles and small, shallow channel access, Aug. 9, 2023. Drone image by Kasey Hovik.

Injury and Predation of Out-Migrating Smolts: Not only does the dam slow upstream migration, but the 17-foot fall onto bedrock injures or stuns out-migrating smolts, making them easy prey for predators that feast just downstream.

Massive Loss of Lamprey Larvae: Lamprey are jawless fish that are among the most ancient vertebrates, having evolved over 130 million years BEFORE the first dinosaurs walked the planet. Lamprey larvae (known as amocetes) spend the first 2 to 7 years of their lives as filter feeders in sediments of slow-moving side channels and alcoves before beginning their migration to the ocean. Even though reservoir drawdowns during past dam repairs have killed untold thousands of amocetes, sprinklers that were planned to keep at least a small percentage of them alive were deployed late, leading to another massive die-off. After the dam owners failed to conduct an adequate salvage required by their permits, dozens of agency employees spent the first few days of the drawdown in a largely futile emergency effort to save as many as possible. “Save” meant moving amocetes to the narrowing flow of the river where many would fall prey to all of the fish in the reservoir that were also crowded into that much smaller space. The cost of deploying so many state and federal workers has not yet been calculated but will likely run several tens of thousands of state and federal tax dollars.

Lamprey larvae stranded by the Winchester Reservoir drawdown, Aug. 7, 2023. Photo by the author.

The Dam DOES NOT Block Access to Invasive Smallmouth Bass: Ryan Beckley, the president of the WWCD, has been quoted as saying “It appears as though the Winchester Dam and its fish ladder, in its current configuration, is keeping out only smallmouth bass. It’s allowing salmon, it’s allowing trout, it’s allowing steelhead in huge and vibrant, healthy numbers.” In a recent News-Review article, Beckley said that without the dam “…every other kind of invasive species that’s in this river [would] migrate their way right up this river and they would destroy this habitat.” These statements are laughable for a couple of reasons.

First, if the ladder was passing “huge and vibrant” numbers of salmon, the ODF&W would not have made it one of the highest priority dams in Oregon for fish passage improvement. But the biggest red herring in this statement is the pervasive myth that the dam is somehow blocking smallmouth bass (smb), an invasive predator known to prey heavily on out-migrating salmonid smolts. The 12-inch steps of the ladder present a much smaller challenge to smb than Red Beach and Burkhart’s Rapids do a few miles downstream – so if smb can make it to the dam, a percentage will make it across.

In a recent conversation with an ODF&W official, I was told that the first observation of smb passing through the ladder was in 1980 when 5 fish crossed the dam, and that they have been traversing the ladder sporadically ever since. Some years, none are counted, but in 2013, 27 were observed passing the ladder. I live 4+ miles upriver from the dam, and about that same year, I saw two adult smb swimming in our eddy. I worried that this was the beginning of the end, but I haven’t seen a single one since. A fishing guide friend saw one at about that time at Gravel Bin, and a former Umpqua National Forest fisheries biologist told me that a team from OSU reported juveniles at the mouth of Steamboat Creek about 20 years ago. So why haven’t all those bass been able to colonize the river above the dam and “destroy this habitat” in over 40 years?

All species of bass including smb require warm, slow water with lots of submerged vegetation – conditions that make smb a real problem in the warmer, slower South and Main branches of the Umpqua. However, the North Umpqua above the dam gets progressively faster and colder, making it very poor bass habitat. Native fish need wild rivers, but exotic fish thrive in domesticated ones.

Reservoir Heats Up Water in Lower North Umpqua: If anything, the reservoir with its warmer, flat water creates far better bass habitat (and poorer salmonid habitat) than the North Umpqua below the dam. As water from the cool North Umpqua spreads out in the shallow reservoir, it is exposed to significantly more solar radiation. As the warmest water from the surface of the reservoir passes over the dam, it adds heat to the last stretch of the river before it joins the South Umpqua at River Forks.

Invasive Aquatic Weeds: The warm, slow water of the reservoir also creates perfect conditions for water milfoil, a highly invasive exotic weed that can impact water chemistry, choke out other native aquatic plants, and create habitat for other invasive species including smb. A large amount of milfoil was released downstream when the dam gates were first opened on Aug. 7th. As the planet continues to warm, we can expect the dam to increasingly degrade the habitat for native species in the reservoir and downstream.

Water milfoil released from the Winchester Reservoir, Aug. 9, 2023. Photo by the author.

Potentially Toxic Materials: Repairs over the last several decades have included the use of pressure treated wood, with older timbers having been treated with copper-chromium-arsenate (yep, it’s as toxic as it sounds). The drinking water for over 37,000 Roseburg residents comes from the south side of the Winchester Dam. No effort is being made to remove that material, and the voids in the dam are being repaired by filing them with polyurethane foam, a know source of microplastic pollution.

Downstream Water Rights: The WWCD was notified by state officials in a January 2023 letter that they were storing more acre feet of water than their filed water right claim. The reservoir refill will begin in early September and will temporarily reduce river flows downstream of the dam during the driest and hottest time of the year, likely impacting North Umpqua instream water rights intended to protect salmonids, particularly the struggling summer steel head run. The WWCD could have installed a coffer dam behind the main dam to create a dry space over the top and face. This would not have required a significant drawdown and would have kept the fish ladder open, but that would have cost more money. Despite the ongoing storage of more water than they claim, the WWCD’s proposal to cut costs on dam repairs received all necessary state and federal permits to dewater the reservoir to the detriment of lamprey, steelhead, and the Oregonians to whom that water belongs.


The Winchester Dam has no ecological value to the North Umpqua River, to the citizens of Douglas County, or to the iconic fish we revere. At an absolute minimum, the fish ladder must be brought up to modern standards. But the less costly and more environmentally responsible option is to simply take out the dam. WaterWatch has offered to take the lead in raising the money to remove the dam, but the WWCD has not surprisingly rejected that offer.

We urge you to learn more about the value of restoring free-flowing waters to one of the crown jewels of southwest Oregon’s natural heritage. Please visit, and other local conservation websites and podcasts, and keep an eye out for Watersheds Moments in your inbox to stay informed on more Winchester Dam details and updates.




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