Martin Fox, Muckleshoot: Monitoring sediment in streams
Martin Fox – Muckleshoot Tribe – Monitoring sediment in streams
The tribe monitored fine sediment in the middle Green River to determine if it was impacting chinook salmon egg survival, as the tribe had noticed lower egg survival compared to other rivers.The stretch of river was from Howard Hansen dam to SR 18.
The objectives were to evaluate spawning gravel and look at sediment delivery in the river and from a landslide and how it related to salmon survival. They sampled during low flow times of the year using a barrel sampler – a big metal cylinder that was driven down into gravel about 30cm to get down to egg pocket and sample the gravel there.
Results showed that levels of fine sediment were greater closest to the dam but all the samples had properly function conditions, so the tribe was able to determine that fine sediment levels probably aren’t at a level that is impacting survival.
With the landslide, near Flaming Geyser State Park, the tribe thought that the sediment from the landslide would be causing some sedimentation in the river. The biggest area that was affected was just immediately downstream of the dam but did not degrade the quality of the gravel to harmful levels. His conclusion is that sediment not too much of a problem and the tribe can start looking elsewhere for the source of the problem.
