Date of Graduation

Spring 2012

Degree

Master of Science in Geospatial Sciences

Department

Geography, Geology and Planning

Committee Chair

Jun Luo

Keywords

GIS automation, application development, ArcObjects, VBA, hydrology assessment, flood magnitude, flood frequency, discharge estimation

Subject Categories

Geology | Hydrology | Water Resource Management

Abstract

This research introduces a prototype development for ArcGIS software that calculates flood discharge estimates (Qt) for 2- to 500- year flood events on unregulated Missouri streams. In spite of increasing faith in Geographic Information Systems (GIS), many modern approaches use manual techniques to identify one or more variables necessary to estimate flood magnitudes. For example, stream gradient (slope) is often determined by observing where a watercourse intersects elevation contours on a topographic map. The automation prototype, built with ArcObjects and Visual Basic for Applications (VBA), emulates a researcher's workflow by defining watershed area and channel slope values from a digital elevation model (DEM). Resulting area and slope measures are then input into National Flood Frequency (NFF) regression equations published by the U.S. Geological Survey (USGS) to estimate recurring flood magnitudes. A t-test comparing manual and GIS-based estimates of 100-year flood events for sites in southwest Missouri suggests no significant difference (t-stat = -0.0234 > t-crit = -1.684) with 95% confidence between sample means of the two methods. However, examination of the regression model's spatial limitations show marked error increases for basins smaller than 5 square miles (mi²), so alternative estimation methods are more appropriate for small basins.

Copyright

© Elijah L. Robison

Campus Only

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