HR: 1330h
AN: H42E-1126    [PDF]
TI: Multi-scale factors influencing stream substrate size within and among watersheds
AU: * Bledsoe, B P
EM: bbledsoe@engr.colostate.edu
AF: Department of Civil Engineering, Engineering Research Center, Colorado State University, Fort Collins, CO 80523 United States
AU: Flores, A N
EM: lejo@mit.edu
AF: Department of Civil and Environmental Engineering, Ralph M. Parsons Laboratory, 77 Massachusetts Avenue, Cambridge, MA 02139 United States
AU: Sanborn, S C
EM: ssanborn@engr.colostate.edu
AF: Department of Civil Engineering, Engineering Research Center, Colorado State University, Fort Collins, CO 80523 United States
AU: Cuhaciyan, C O
EM: fluvial@engr.colostate.edu
AF: Department of Civil Engineering, Engineering Research Center, Colorado State University, Fort Collins, CO 80523 United States
AB: Variables representing processes at multiple spatial scales that influence stream bed substrate at the outlet of a basin (a sample location) are developed to augment existing models that include only stream bed gradient and upstream drainage area. These multi-scale models can explain up to 95 percent of the variation in stream bed substrate size and consistently explain an additional 32 to 52 percent of the variation in substrate size when compared to models that use only channel gradient and drainage area. Results demonstrate that variables reflecting valley topographic configuration in the vicinity of a sample location explain significant additional variation in substrate size. When the geographic extent being considered exhibits significant variability in hydroclimatic processes and basin lithology, accounting for variability in these controlling factors can significantly increase the explanatory power of these models. In contrast, when considering an area of relatively homogeneous hydroclimatic processes and basin lithology, including variables that reflect the distribution of flow energy and/or relief in the upstream channel network significantly improves models to predict substrate size. The ability to produce reliable predictive models of substrate size using only variables generated from geospatial data is also addressed. Values of channel gradient obtained through field survey are substituted with values of channel gradient sampled from digital elevation models and model development repeated. Models developed in this fashion explain up to 91 percent of the variation in stream bed substrate size and can, in general, explain as much or more variation in substrate size as models that use only field surveyed channel gradient and drainage area. Furthermore, when appreciable variability in hydroclimatic processes and basin lithology exists, models using only variables derived from geospatial data can explain more variation in substrate size than similar models that use field surveyed channel gradient. Important applications for several fields that could benefit through these analyses are discussed.
DE: 1815 Erosion and sedimentation
DE: 1824 Geomorphology (1625)
DE: 1848 Networks
SC: Hydrology [H]
MN: 2003 Fall Meeting