Document Type

Dissertation - Open Access

Award Date

2021

Degree Name

Doctor of Philosophy (PhD)

Department

Civil and Environmental Engineering

First Advisor

Suzette Burckhard

Keywords

Dataset resolution, Hydrologic analysis, Ungauged watershed, Watershed processing, Watershed subdivision

Abstract

The increasing application of geographic information system (GIS) technology in watershed modeling makes is necessary to further evaluate its impacts on runoff characteristics as a basis for improved hydrologic analysis in ungauged watersheds. Experts in the field of water resources and hydrology have recommended the practice of subdivision when modeling a watershed, and the use of observed data from hydrologically similar watershed to calibrate and validate an ungauged watershed’s model. However, previous studies have failed to adequately address the issues of watershed heterogeneity, spatial and temporal variability in physical parameters, GIS data resolution issues, including artifacts in automated extraction of topographic attributes from elevation datasets. This study utilized the US Army Corps of Engineers Hydrologic Engineering Center Hydrologic Modeling System (HEC-HMS) to evaluate the effects of watershed subdivision and input data resolution on peak discharge in ungauged watersheds. To better understand the underlying processes in ungauged watershed hydrology, runoff hydrographs were simulated at the outlets of study areas located in different hydrological subregions and subdivided into different subdivision scenarios or levels. Simulation results show that total channel slopes and total flow lengths increased with further subdivision, resulting in high peak discharges. Similarly, runoff hydrographs at the outlets of different resolution models were simulated and analyzed. Simulation results indicate that peak discharge values increased as finer resolution datasets were resampled to coarser resolutions with a slight reduction in the sizes of drainage areas. A better understanding of a watershed’s runoff characteristics is a basis for improved hydrologic analysis of ungauged watersheds.

Number of Pages

141

Publisher

South Dakota State University

Rights

Copyright © 2021 the Author

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