Sara Muir McCune

Graduation Year


Date of Thesis Acceptance

Fall 5-15-2010

Major Department or Program

Geology - Environmental Studies


Robert J Carson; Nicholas E. Bader


Road networks are an integral part of the hydrologic system of many forested watersheds . The U.S . Forest Service (USFS) alone has over 616, 379 kilometers of roads on its land — more than the total mileage of all interstate highways . Numerous studies have shown that roads contribute vast amounts of sediment to streams, negatively impacting the stream ecosystems . Because the USFS has limited resources, it is important that it target for improvement roads th at have strong negative effects on their watersheds . To do this, forest managers must understand the factors that create ―high - risk‖ roads . In this study, we used the Geomorphic Road Analysis and Inventory Package data collection method to inventory road features that may relate to sediment and water delivery in the Wall Creek Watershed, located in Oregon’s Umatilla National Forest . Inventories included data on flow path length, drain point type, flow obstructions, elevation and vegetation . We used thes e data in a model to determine which road features most strongly predicted stream connectivity probabilities . Results suggest that stream connectivity is best predicted by a model that includes distance from stream, drain point type, and elevation . These findings can be used to adjust road management plans to diminish sediment input into streams, and to improve the overall health of the watershed .

Page Count


Subject Headings

Water -- Pollution, Forest roads, Roads -- Environmental aspects, Umatilla National Forest (Or. and Wash.), Streams -- Oregon, River sediments, Road drainage, Runoff, Whitman College -- Dissertation collection 2010 -- Environmental Studies-Geology

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Public Accessible Thesis

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