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GEOREF RECORD

A combined GIS and HEC model for the analysis of the effect of urbanization on flooding; the Swan Creek watershed, Ohio

Abstract

This study investigates the effects of changes in land-use on the hydrology of the Swan Creek watershed in Lucas County, Ohio, over a thirty-year period. The study presents the GIS based runoff models and the HEC-RAS Flood analysis for the watershed. The runoff modeling was performed using a modification of the rational formula first proposed by Rossmiller in 1980. The C factor (land use) in the rational equation (Q = CIA) is modified to account for land use, soil type and slope factors. Four model runs for each of the land-use coverages were created based on the statistical precipitation recurrence intervals: P (sub 10) , P (sub 25) , P (sub 50) , P (sub 100) (a total of 12 model runs). The models differed only in the basic land-use classifications for each decade of interest. The runoff analysis predicts that increased runoff volumes in the watershed are directly related to increasing urbanization. The study showed that runoff volumes of a P (sub 100) storm in 1973 of certain sub-basins has the equivalent runoff of a P (sub 10) storm in 1995. The flood modeling was performed in the Army Corps of Engineer's Hydrologic Engineering Center's River Analysis System (HEC-RAS). Twelve model runs were also created in HEC-RAS to evaluate the effect of the land-use changes in each of the time periods for each of the storms. The study showed that flood extent of a P (sub 50) storm in 1973 across the watershed has the equivalent flood extent of a P (sub 10) storm in 1995. The flood modeling predicts that the Swan Creek hydrologic system responds more quickly and severely today to events that would have been smaller in the past.


ISSN: 1078-7275
EISSN: 1558-9161
Coden: ENGEA9
Serial Title: Environmental & Engineering Geoscience
Serial Volume: 8
Serial Issue: 1
Title: A combined GIS and HEC model for the analysis of the effect of urbanization on flooding; the Swan Creek watershed, Ohio
Affiliation: Ohio Environmental Protection Agency, Division of Drinking and Ground Water, Columbus, OH, United States
Pages: 47-61
Published: 200202
Text Language: English
Publisher: Association of Engineering Geologists and the Geological Society of America, College Station, TX, United States
References: 40
Accession Number: 2002-064359
Categories: Hydrogeology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 5 tables, sketch maps
N41°23'60" - N41°43'00", W83°52'60" - W83°10'60"
Secondary Affiliation: Bowling Green State University, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2022, American Geosciences Institute.
Update Code: 200220
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