Angelo Coast Range Reserve

29 Jul, 03 AM - 29 Jul, 01 PM

Traditional bedload transport models predict reduced sediment stability with increasing slope because of the force of gravity pulling sediment downhill. However, a new theory suggests that particles of the same size may be more stable on steep slopes because the critical Shields stress for initial sediment motion may increase with slope. We are exploring the implications of this new theory in Fox Creek, a steep, forested headwater stream in the Angelo Coast Range Reserve of Mendocino County, California where large boulders with diameters up to one meter are ubiquitous throughout the creek. Our preliminary analyses suggest that the largest boulders were not likely transported to their present location by stream flow, but may have arrived by landslides or mudslides. We compare the water depths required to move these boulders using a traditional model and the slope-dependent model for calculating critical Shield?s stress. The boulders in this steep, headwater stream were probably not transported by stream flow; and higher flows may generally be needed to move boulder in steep streams than previously thought.

Visit #15855 @Angelo Coast Range Reserve

Approved

Under Project # 10352 | Research

Mobility of boulders in steep headwater streams: evaluation of the critical Shield's stress model

graduate_student - University of California, Berkeley

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Group of 2 Graduate Student Jul 29, 2008 (1 days)

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Day use 2 Jul 29 (10 hours)