HR: 15:25h
AN: H13M-07    [Abstracts]
TI: Drainage Density: A Framework for Predicting Peak and Low Flows in Ungaged Catchments
AU: Jefferson, A
EM: ajefferson@uncc.edu
AF: University of North Carolina-Charlotte, Department of Geography and Earth Sciences 9201 University City Blvd., Charlotte, NC 28223, United States
AU: * Grant, G E
EM: gordon.grant@oregonstate.edu
AF: USDA Forest Service, Pacific Northwest Research Station 3200 SW Jefferson Way, Corvallis, OR 97331, United States
AU: Lewis, S L
EM: sarah.lewis@oregonstate.edu
AF: Oregon State University, Department of Geosciences, Corvallis, OR 97331, United States
AB: Drainage density, a measure of the linear concentration of streams on the landscape, has been recognized as an important geomorphic descriptor for decades, but has received comparatively little attention as a predictor of hydrologic behavior. Here we present a conceptual and analytical framework linking the underlying geologic structure of a landscape through drainage density to peak flow and drought response. In this framework, drainage density provides a first-order measure of the ratio of surface to sub-surface flow at the landscape scale, hence storage and response times during floods and droughts. We argue that this landscape-level metric can constrain estimates of peak flows and drought response in ungaged basins. We present data from the U.S. Pacific Northwest demonstrating the strong coupling between geology, climate, drainage density, and hydrologic response. We then show that unit peak flows increase with drainage density and minimum 7-day flows decrease with drainage density, although other factors also contribute to these relationships. The strength of the relationship between drainage density and flow increases as the return period between events increases. Thus, this relationship could be used to predict the magnitude of long return period events if one event of comparable return period is known in the region.
DE: 1812 Drought
DE: 1821 Floods
DE: 1824 Geomorphology: general (1625)
DE: 1830 Groundwater/surface water interaction
DE: 1879 Watershed
SC: Hydrology [H]
MN: 2007 Fall Meeting