HR: 09:15h
AN: H51L-06    [Abstracts]
TI: High Resolution Mapping and Interpretation of Channel and Floodplain Topography With a Narrow-Beam Terrestrial-Aquatic Lidar
AU: * McKean, J
EM: jmckean@fs.fed.us
AF: U.S.Forest Service, Rocky Mountain Research Station, 322 E. Front St. Suite 401, Boise, ID 83702, United States
AU: Isaak, D
EM: disaak@fs.fed.us
AF: U.S.Forest Service, Rocky Mountain Research Station, 322 E. Front St. Suite 401, Boise, ID 83702, United States
AU: Tonina, D
EM: dtonina@fs.fed.us
AF: University of California at Berkeley, Dept. of Earth and Planetary Science, 307 McCone Hall, Berkeley, CA 94720, United States
AU: Wright, W
EM: wright@lidar.net
AF: NASA, Goddard Space Flight Center, Wallops Flight Facility Code 972, Wallops Island, VA 23337, United States
AU: Kinzel, P
EM: pjkinzel@usgs.gov
AF: U.S. Geological Survey, 4620 Technology Drive MS 413, Golden, CO 80401, United States
AB: Basic description of channel and floodplain topography remains a fundamental challenge for modeling flow and sediment transport or even simply mapping habitat. Standard field wading and boat surveys of stream topography are limited by costs and logistics to relatively small sample reaches and floodplain maps are seldom well- integrated with channel bathymetry. We used the NASA Experimental Advanced Airborne Research Lidar (EAARL) to map channel and floodplain topography and investigate geomorphic controls on physical habitat in two diverse channels in the watershed of the Middle Fork Salmon River, Idaho. Bear Valley Creek is a small low-gradient gravel-bed stream flowing across an unconfined valley filled with glacial outwash materials. A hierarchy of nested geomorphic features is evident in this channel with the broadest fluvial domains a legacy of ~15,000 years of post-glacial valley evolution. Contemporary hydraulics operate on this broad template and control two smaller scales of pool-riffle morphology. Salmon spawning patterns closely reflect these nested physical domains, demonstrating how geomorphic history can influence modern distributions of aquatic habitat and organisms. In contrast, Big Creek is a higher-gradient stream predominately confined by steep side slopes in a deep valley. Here, the distribution of geomorphic domains and physical habitat is controlled by modern erosion processes and rock quality. Tributaries and valley walls contribute coarse debris, up to large boulders, to the channel, resulting in very rough and poorly organized bed topography. Tributary fans also function as local grade control with sediment deposition in lower-gradient reaches upstream of fans. A GIS toolkit is under development to extract at-a-station channel metrics from EAARL data, including for example, cross section and longitudinal profile characteristics. A new investigation has also begun to further investigate the quality of EAARL data. This study will explore the question of how well we must describe channel topography to adequately: i) map the spatial distribution of physical habitat for management purposes and in support of organism population growth models, and ii) define boundary conditions for flow and sediment transport predictions using the USGS model MD SWMS.
DE: 0439 Ecosystems, structure and dynamics (4815)
DE: 1825 Geomorphology: fluvial (1625)
DE: 1855 Remote sensing (1640)
DE: 1856 River channels (0483, 0744)
DE: 1895 Instruments and techniques: monitoring
SC: Hydrology [H]
MN: 2007 Fall Meeting