PROJECT DESCRIPTIONS

Fluvial Geomorphology

Erosion & Deposition of Stream and River Channel Sediments, Cedar River, WA

Client: King County, WA

Project Description: Sue Perkins investigated erosion and bank stability problems caused by urban runoff in 38 creeks. The degree of instability was related to several factors: the magnitude of flow increases, geologic substrate, and channel slope and morphology. Findings from the investigation were used as a predictive tool to identify locations where future flow increases are likely to cause bank erosion problems. Cross-section surveys and channel migration mapping were used to assess sediment deposition trends, channel stability, and loss of habitat area in the mainstem Cedar River.

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Channel Migration Hazard Mapping, Green, Snoqualmie, Raging and Tolt Rivers, WA

Client: King County, WA

Project Description: Sue Perkins conducted channel migration studies for 32 miles of river. Aerial photographs and historic maps, field observations, and analytical methods were used to compile maps showing historic channel positions, calculate historic migration rates, identify potential avulsion channels, analyze causes of migration rate changes, and develop channel migration hazard maps. Sue Perkins is presently conducting a similar analysis on the lower Hoh River for the Hoh Indian Tribe.

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Landslide and Channel Response Inventory, Stillaguamish WA

Client: Stillaguamish Tribe, Tulalip Tribes, and Snohomish County

Project Description: : Sue Perkins conducted an extensive landslide inventory based on aerial photographs and assembled a master landslide inventory of 1,080 landslides covering the entire Stillaguamish basin. The timing and volume of landslide sediment delivered to channels was estimated. Successive aerial photographs were used to inventory widening and narrowing of channels with anadromous fish use. Channel response was related to riparian harvest and landslide delivery (co-authored with Brian Collins).

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