Yakama Nation Fisheries Upper Columbia Habitat Restoration Project contracted Inter-Fluve to perform a reach assessment, and design of a 2,200-foot-long groundwater-fed side channel to provide year-round rearing habitat for summer chinook and steelhead. The side channel intercepts groundwater, collecting hyporheic water near the river, and conveys it to the head of the side channel. The developed spring provides approximately 4 cubic feet per second of flow in the new side channel during the lowest Methow River flows.
Why groundwater? Groundwater buffers the water temperature, helping to maintain a more consistent and optimal fish rearing temperature. During the peaks of winter and summer, groundwater-fed side channels provide critical thermal refuge habitat for juvenile fish which experience physiological stress with overly warm or cool temperatures.