HR: 0800h
AN: H41D-0437    [Abstracts]
TI: Consequences of Urban Streamflow Patterns for Channel Form and Streambed Disturbance
AU: * Konrad, C P
EM: cpkonrad@usgs.gov
AF: U.S. Geological Survey, 1201 Pacific Ave. Suite 600, Tacoma, WA 98402 United States
AB: Changes in streamflow patterns as a result of urban development are well documented at the scale of individual storm events, but some of the geomorphic and ecological consequences of urban streamflow patterns accrue of over longer time scales. Inter-annual measures of streamflow patterns are needed to assess the geomorphic and ecological impacts of hydrologic changes in urban areas. Channel form and stability in 16 streams in western Washington were related to inter-annual streamflow patterns that are modified by urban development. Streams with short-duration high flows are narrower than expected from empirical relations (hydraulic geometry) referencing flood frequency and are likely to have more frequent and extensive bed material entrainment. Stream channel morphology, regardless of the level of urban development in the basin, is better explained by measures of the duration of high flows. Although stream channels may adjust to urban streamflow patterns through the expansion of channel dimensions or an increase in the size of bed material, these adjustments may be insufficient to re-establish the benthic disturbance regime produced by bed material entrainment during high flows because of a differential increase in the frequency of high flows compared to the cumulative duration that those flows are exceeded.
DE: 1803 Anthropogenic effects (4802, 4902)
DE: 1825 Geomorphology: fluvial (1625)
DE: 1834 Human impacts
DE: 1860 Streamflow
SC: Hydrology [H]
MN: Fall Meeting 2005