HR: 15:15h
AN: H42I-07    [PDF]
TI: Integrating spatial watershed and runoff (quantity and quality) data to map and quantify the dominate sources of watershed runoff
AU: * Beighley, E
EM: beighley@icess.ucsb.edu
AF: Donald Bren School of Environmental Science and Management, University of California, Santa Barbara, CA 93106 United States
AU: Leydecker, A
EM: al@icess.ucsb.edu
AF: Donald Bren School of Environmental Science and Management, University of California, Santa Barbara, CA 93106 United States
AU: Dunne, T
EM: tdunne@bren.ucsb.edu
AF: Donald Bren School of Environmental Science and Management, University of California, Santa Barbara, CA 93106 United States
AU: Melack, J M
EM: melack@lifesci.ucsb.edu
AF: Donald Bren School of Environmental Science and Management, University of California, Santa Barbara, CA 93106 United States
AB: Basin landscapes possess an identifiable spatial structure, fashioned by climate, geology and land use, that affects their hydrologic response. This structure defines a basin's pattern of runoff and stream chemistry, its hydrogeological signature. In southern California, coastal watersheds are commonly separated into two geologic regions: mountainous uplands with steep, permeable soils over shallow bedrock and mild sloping coastal plains with deeper soils and debris deposits. The region is characterized as having a Mediterranean climate providing long dry periods and a brief winter (Dec-Mar) rainy season with short duration, intense rainfall. Using commonly available GIS data and measured rainfall and runoff data, we present a new approach for interpreting a basin's hydrogeological signature to identify the spatial distribution of dominant runoff mechanisms and pathways. Using spatially distributed high temporal resolution stream (quantity and quality) data, we verify our inferred distribution of runoff sources and quantify their relative importance at the watershed outlet. The benefit of our research is an integrated spatial representation of runoff quantity and pathways, which is useful for interpreting functions of runoff in the recruitment and transport of sediment and other contaminants. Our hydrogeological interpretation method also provides a quantitative approach for partitioning watersheds into similar hydrologic response units appropriate for hydrologic modeling. Our methods are illustrated in a case study focused on two watersheds (24 and 30 km2) draining the southern coast of California for water years 2002 and 2003. Based on our hydrogeological interpretation, we partition streamflow into both surface and subsurface runoff, where surface runoff is from either urban or rural surfaces and subsurface runoff is either interflow from steep shallow soils or groundwater from bedrock and coarse-textured fan deposits.
UR: http://sbc.lternet.edu/
DE: 1829 Groundwater hydrology
DE: 1860 Runoff and streamflow
DE: 1871 Surface water quality
DE: 1894 Instruments and techniques
SC: Hydrology [H]
MN: 2003 Fall Meeting