HR: 1340h
AN: H13E-1367    [Abstracts]
TI: Physical Process Time and Space Scales Related to River Restoration
AU: * Randle, T
EM: trandle@do.usbr.gov
AF: US Bureau of Recalamation, POB 25007, Attn D 8540, Denver, CO 80225 United States
AU: Boutry, J
EM: jboutry@do.usbr.gov
AF: US Bureau of Recalamation, POB 25007, Attn D 8540, Denver, CO 80225 United States
AB: River restoration studies need to consider stream dynamics, evolution, rates of adjustment, and relative effects of various human disturbances. The history of stream channel adjustment typically needs to be investigated over a time scale of decades to centuries to include the time before human disturbance. An investigation of historical change will help with understanding the processes of physical change, how the system is presently functioning, and how the system will likely function in the future. In our studies for restoration of Pacific Northwest rivers, the spatial area of study is typically tens to hundreds of square kilometers to include water flow and sediment source areas, the reaches and areas of disturbance, and downstream reaches of potential influence. Sediment source areas can include the upstream watershed, local landslides, bank erosion, and channel degradation. Upstream sediment sources can also be blocked by storage reservoirs. Terrace, floodplain, and channel topography and vegetation coverage need to be measured at a scales ranging from centimeters to meters, while sediment grain sizes need to be measured at a scale of millimeters. For example, on the Quinnault and Dungeness Rivers, we rely on LIDAR surveys, historical aerial photography, radio-carbon dating, field surveys, grain size analyses, and hydraulic modeling to develop an understanding of river processes on which to base our restoration strategies.
DE: 1808 Dams
DE: 1815 Erosion
DE: 1825 Geomorphology: fluvial (1625)
DE: 1834 Human impacts
SC: Hydrology [H]
MN: Fall Meeting 2005