--> Abstract: Evaluation of High-Resolution Digital Elevation Models for Creating Inundation Maps, by M. A. Wonkovich; #90087 (2009).
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Evaluation of High-Resolution Digital Elevation Models for Creating Inundation Maps

M. A. Wonkovich
Bowling Green State University

The Village of Pemberville, Ohio experiences frequent flooding. Accurate Previous HitfloodNext Hit maps are needed to reduce damage caused by these floods. Photogrammetry software was used to create a high-resolution DEM using two overlapping USGS NAPP aerial photographs each with resolutions of 1:40,000 and scanned at 1800 DPI. The resulting DEM had a resolution of 0.57 m (1.87 ft) and a minimum detectible elevation of 0.95 m (3.1 ft). HEC-GeoRAS was used to produce cross-sections of the North Branch of the Portage River and an inundation map of a 100-year Previous HitfloodNext Hit from the high-resolution DEM. The inundation map was compared to a 100-year Previous HitfloodNext Hit inundation map produced with ground surveyed cross-sections provided by TMACOG and the FIRM for Pemberville. The datasets produced Previous HitfloodNext Hit profile elevations of 196 m (643 ft) along the North Branch of the Portage River in the Village of Pemberville, which is the same as on the FIRM. When compared areally, the high-resolution DEM data produced larger Previous HitfloodTop extents than both the surveyed data and the FIRM of the village due to the length and distance of the cross-sections. Different lengths and large distances between cross-sections can cause large changes in the width of the bounding polygon, not accurately representing the floodplain, and limiting the extent of the estimated inundation.

AAPG Search and Discover Article #90087 © 2008 AAPG/SEG Student Expo, Houston, Texas