Update:
Momentum continues to build for restoring chinook salmon and steelhead runs to the Similkameen River, a major tributary of the Okanogan River above Oroville. Enloe Dam, a wall of concrete without a purpose for the last 63 years, presents an insurmountable obstacle to fish passage into 340 miles of cold-water habitat on the upper Similkameen River. Just last week, the B.C. Minister of the Environment George Heyman sent a letter of support to Washington’s Director of Ecology, Laura Watson, supporting the removal of the dam, “subject to consultation with Indigenous nations who rely on salmon to support their communities.” The Confederated Tribes of the Colville Reservation and the Lower Similkameen Indian Band in British Columbia have both expressed support for removing the dam.
Okanogan Public Utility District (OPUD) manages Enloe Dam. The dam stopped producing power in 1958 and currently fulfills no function. Water simply flows over the spillway. In 2019, OPUD voted unanimously not to electrify the dam. However, the Utility District, and in turn rate payers, continue to pay for dam upkeep: currently OPUD is funding a required $7 million dam-safety study.
Dam removals are complex undertakings. OPUD does not want to shoulder the cost nor the liability of dam removal. The Utility District has identified criteria that would need to be met to consider dam removal. Among the criteria are an “approval that the Canadian Government will allow new fish populations to cross the border” a “feasibility assessment that collects and evaluates scientific data,” and a “delineation of suitable habitat for anadromous fish above the dam, with data.” The letter from the B.C. Minister of the Environment indicates an openness to transboundary salmon migration into Canada; the Colville Tribes recently commissioned a conceptual dam removal plan to begin assessing the feasibility of removal; and Trout Unlimited is conducting ongoing fish habitat studies with NOAA, the Colville Tribes, and the Upper and Lower Similkimeen Indian Bands. Tribes, agencies and NGOs are working together to address OPUD’s concerns and overcome the obstacles to removal.
The method of dam removal—dredging and capping sediment versus allowing it to flow downstream—depends upon the toxicity levels found in the 2.9 million cubic yards of sediment piled up behind the dam. Historic mining did occur upstream of the dam in the Similkameen watershed. In 2019, USGS collected sediment samples above the dam. This summer, they will be releasing an interpretive report based their findings. Further sampling needs to be done to compare these levels to nearby control levels followed by a complete Sediment Management Plan. These next steps could more accurately determine the final cost and help develop a specific strategy for removal.
Removing a dam safely is no small feat, but it has been accomplished at similar and larger scales on numerous rivers around Washington and throughout the West. Often these removals are collaborative efforts in which costs and liability are managed creatively.The potential of restoring hundreds of miles of habitat for endangered salmon species make the challenges worth confronting.
Resources:
Columbiana website