January 2013
The 1,500 foot long side channel on the Methow River at Whitefish Island is one of the few side channels in an eight mile reach known as the middle Methow River. Side channels like these can provide important habitat for juvenile fish, particularly if they offer what biologists call habitat complexity. Scientists believe that stream channel and floodplain complexity are the most important factors in improving the productivity of Chinook salmon in the Upper Columbia Basin.
A complex stream habitat includes several environments – fallen trees, large boulders, gravel, and vegetation often complemented by ground water springs. Unlike a scoured streambed, channel complexity provides tree roots and shade, places for the juvenile fish to hide from predators as
they grow, and places to rest on their way to the ocean.
Side channels like this one in the Methow provide sheltered places
for young salmon to grow.
In 2012, a partnership between the Upper Columbia Salmon Recovery Board and the Bureau of Reclamation resulted in the installation of log jams and wood assemblies at the head of Whitefish Island and along the banks of the side channels. These logjams will help catch additional wood and develop natural logjams. This will create high quality side channel rearing habitat, improve surface and groundwater connection to the floodplain, and help plants and vegetation develop along the stream banks. Wood placements throughout the channel will provide more habitat complexity and pool depth in both the the side channel and the mainstem of the river.
Watch a video about the project:
Left: 100 year flood plain superimposed over LiDAR image of Whitefish Island.
Right: Engineered logjams shown in this conceptual drawing help create habitat complexity on this sidechannel at Whitefish Island.
