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A watershed modeling analysis of fluvial geomorphologic influences on flood peak attenuation
Author(s) -
Woltemade Christopher J.,
Potter Kenneth W.
Publication year - 1994
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/94wr00323
Subject(s) - overbank , hydrology (agriculture) , flood myth , environmental science , watershed , surface runoff , floodplain , fluvial , attenuation , magnitude (astronomy) , storm , riparian zone , geology , geomorphology , geotechnical engineering , geography , optics , ecology , oceanography , physics , cartography , archaeology , structural basin , machine learning , astronomy , habitat , computer science , biology
Flood peak attenuation caused by storage of flood water on overbank surfaces effectively reduces the magnitude of peak discharges in some, but not all watersheds. Several geomorphic factors that affect the storage and conveyance of flood water were investigated to assess their quantitative influence on downstream peak discharges. The MIKE11 rainfall‐runoff and hydrodynamic models were calibrated for the Grant River watershed, southwestern Wisconsin. Alternative geomorphic conditions were modeled and compared to the original case. Results indicate that channel‐floodplain‐terrace morphology, valley width, stream slope, and hydraulic roughness each influence peak discharges, especially for moderate magnitude (5‐ to 50‐year recurrence interval) floods. Peak discharges varied by as much as 49% between simulations depending on geomorphic conditions. Watersheds that effectively attenuate produce peak discharges that are strongly correlated with total runoff. Watersheds that attenuate little produce peak discharges that exhibit greater variance due to storm intensity and duration.