David Cooper
8 November 2000
Fluvial Geomorphology
Writing Assignment

Is the Skokomish river in equilibrium? No, it is not in good health. There are three things that have contributed to its poor condition. First, in 1926 Tacoma Power and Light constructed a dam upstream that has diverted 90% of the water in the North Fork of the Skokomish to their hydro generators. This dramatic decrease of water flow has allowed three inches of sediment to build-up. Salmon need gravel -- not sediment to lay eggs in. Floods are now less frequent; causing the nutrients to flush down the system instead of spreading into the flood plain area. Second, parts of the river have been modified to make the river more manageable. The Army Corps of Engineers has channelized or straightened certain stretches. This has caused the river to run faster and interferes with its natural tendency to meander into tight curves. Without a meandering river, a certain aspect of the river is missing. It will not have depressions and shallows which are caused by the actions of helical currents and thalwegs. Salmon need these depth variances to be happy. Third, there are still unsound logging practices upstream which washes an enormous amount of sediment into the river system. Loggers' road building practices also contribute to even more washout. Culvert placement will sometimes cut off salmon runs entirely.

It is good to see the river work toward a sense of stability again. I personally see two ways this is being accomplished. The river is doing the best it can on its own and with the available kinetics or energy needed to change the river. Over time it can reestablish another equilibrium using these new factors. As the river regains momentum, the meanders increase and sediment loads increase. Also, humans are doing what they can to assist in the process. We saw this on a field trip to the Skokomish reservation. Four river sites were using various means to restore the rivers' dynamic equilibrium. We saw ways to reconnect channels and methods to improve salmon habitat by simply using trees stumps. Dikes were removed and culverts were replaced. Jute matting and trees were placed to stabilize soils and enrich the riparian zone. Our guide on the tour was Jim Park who works closely with the Skokomish tribe. He claimed that initial salmon return numbers are promising since habitat is slowly returning to the lower parts of the river. However, there is still three times the normal sediment load still washing into the streams. To fully address and restore salmon, two issues still must be examined closely -- hatcheries and hydropower. Hatcheries are a temporary engineering fix to an ecological problem. Dams cannot help matters when entire rivers are blocked to returning salmon. When the river is once again healthy, salmon numbers will be healthy too.