Winchester Dam Repair Project 2023

At 133 years old, Winchester Dam on the North Umpqua River is an aging facility that has been experiencing structural decline in the last decade. These issues include leaking water through the dam face that present additional false attraction flow for migrating fish. Additionally, the dam needs structural integrity testing per the Oregon Water Resources Department (OWRD) requirements, which is a health and human safety issue. The repairs and testing require the owners of the dam, the Winchester Water Control District (WWCD), to temporarily dewater the area behind the dam, subsequently closing the fish ladder.

During this period of dewatering, ODFW is significantly concerned about fish passage at the dam and other potential impacts to fish and aquatic species.

After lengthy discussions with the WWCD, ODFW issued authorizations for a three-week dewatering period from August 7 – 28, 2023. The ODFW authorizations include a number of terms and conditions during this period. Given the risk to fish and other aquatic species, ODFW wants the work by the WWCD to get completed as quickly as possible and have taken other steps to monitor the work during the in-water work window and conditions to complete the work (see below). Other aspects of the repair work occurring on the dam have been authorized by additional state and federal agencies (see below).

WWCD submitted an In-water Work Window Extension Request (IWWE) to the Oregon Department of Fish and Wildlife (ODFW) the afternoon of August 23, 2023 requesting an extension until Sept 4.  ODFW approved the IWWE late in the evening on August 24, 2023 to extend in-water work from August 29 - 31, 2023 with an allowance that the temporary bridge and its associated materials must be removed the next day (September 1, 2023). NMFS and USACOE also approved the IWWE.

WWCD submitted a second IWWE to ODFW late afternoon August 30, 2023 requesting an extension through September 6, 2023. ODFW conditionally approved the request late afternoon September 1, 2023 to have the affected project area and fish ladder fully rewatered by 5 p.m., September. 6, 2023. This IWWE can be found here. NMFS and USACE also approved the IWWE.

ODFW permits issued to WWCD:
ODFW Fish Passage Authorization #PA-17-0138 (issued December 29, 2022).
ODFW Fish Passage Authorization #PA-17-0152 (issued August 14, 2023).
ODFW Wildlife Division Letter of Authorization for herpetofauna (issued July 25, 2023).
ODFW Fish Division Rescue Salvage Authorization #27400 (issued July 27, 2023, Modification 1 issued July 31, 2023, Modification 2 issued August 10, 2023, Modification 3 issued August 25, 2023, Modification 4 issued Sept. 1, 2023).

Why was the period of Aug. 7-28 chosen? Won't it harm summer steelhead and other migratory fish—especially when you had to close the North Umpqua to angling this year?

Although some adult summer steelhead and possibly coho salmon may be attempting to migrate above Winchester Dam during this work window, based on historic run timing data (including a more focused look from 2015-2021 for coho and steelhead) ODFW has chosen the period which will least impact these populations.

Summer steelhead migration: Generally, there are two "peaks" of this run. The first is the larger of the two and generally occurs in late-June to mid-July with the second smaller pulse of fish occurring in October and November. The repair timeframe was chosen as it will have the least impact based on previous observations.

An angling closure was enacted on the North Umpqua because current low summer steelhead returns are unlikely to meet our critical abundance of 1,200 wild fish. The closure from July 31-Nov. 30, 2023 primarily protects summer steelhead that have already migrated above Winchester Dam as part of the first "peak" referenced above.

Coho salmon presence: Historic run timing for these fish indicates that the earliest passage at Winchester Dam is in late August. If warmer temperatures persist, this is likely to be delayed further.

Will any other migratory fish be impacted?

There are likely high numbers of juvenile Pacific lamprey in the substrate upstream of the reservoir, which will be exposed when the dam is de-watered and water levels drop. Per the terms of their fish salvage authorization (issued in conjunction with the fish passage permit), dam owners are responsible for salvaging any Pacific lamprey, and other fish, and getting them back into the river as soon as possible to minimize mortality.

ODFW continues to be on site during the repair work to monitor and provide guidance to the contractor on best management practices for salvage and fish passage.

Are other agencies involved in the permitting process for the WWCD?

Yes. Because the project impacts migratory Threatened and Endangered fish species, dam safety and water quality, other agencies were involved in permits for this work and will be monitoring impacts along with ODFW. Please contact these agencies for additional information. There may be other permits that were issued that are not on this list.

Oregon Department of Environmental Quality's 401 Water Quality Certification (issued July 18, 2023)
National Marine Fisheries Service Section 7 BiOp WCRO-2022-02717 (issued July 20, 2023)
U.S. Army Corps of Engineers verification NWP-2018-505-1 (issued July 26, 2023).

Why doesn't ODFW require Winchester Dam to meet fish passage standards?

Under Oregon's fish passage statutes set by the Oregon State Legislature, only certain events trigger fish passage requirements to upgrade or change current fish passage to comply with modern rules. Those events include installation, major replacement, a fundamental change in permit status (e.g., new water right, renewed hydroelectric license), or abandonment of the artificial obstruction. The repair happening at Winchester Dam did not trigger fish passage rules to upgrade the ladder at the time it was permitted in 2022.

Some advocates are claiming the repairs will release sediments into the river. How will this impact water quality?

Both DEQ and NMFS considered these factors in issuing their permits/opinions and have authority to enforce requirements related to water quality. Questions should be directed to them.

Why isn't a coffer dam being used during construction?

A coffer dam is another construction option to isolate Winchester Dam for the repair work. Consistent with past practice, ODFW evaluated the fish passage plan developed by the applicant, which did not include a coffer dam. Questions about why a coffer dam was not included should be addressed to WWCD. Regardless, ODFW worked with the applicant to adjust proposed passage actions in order that they have the least impact on native fish, especially by minimizing the construction period and making sure the construction is conducted during the period when the fewest migratory fish will be present.

Will changes in river flows affect fish and boats in the river?

ODFW, as part of the salvage authorization, has placed conditions on the rate of both drawdown at the start of de-watering the upstream reservoir and refill of the reservoir after work is completed. Rates were selected to minimize impacts to upstream and downstream aquatic species, as well as boats in the river downstream.

Have fish have been killed during the repair and how many?

ODFW has seen mortality of juvenile Pacific lamprey but quantifying the amount will take time.

ODFW issued WWCD a salvage authorization permit which outlined terms and conditions to avoid mortality. ODFW staff have been on site since the drawdown/dewatering began to monitor the salvage efforts of WWCD and through the end of construction.

Shortly after dewatering began, ODFW saw that emergency salvage of juvenile Pacific lamprey was needed. ODFW gathered a crew of 50 to 60 staff from the agency, other state and federal agencies, and the Cow Creek Band of Umpqua Tribe of Indians to salvage lamprey. This emergency crew worked for two days. Salvage counts are not yet finalized.