Physically Based, Hydrologic Model Results Based on Three Precipitation Products

Authors

  • Singaiah Chintalapudi,

    1. Respectively, Graduate Research Assistant (Chintalapudi), Assistant Professor (Sharif), and Graduate Research Assistant (Elhassan), Department of Civil and Environmental Engineering, University of Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249
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  • Hatim O. Sharif,

    1. Respectively, Graduate Research Assistant (Chintalapudi), Assistant Professor (Sharif), and Graduate Research Assistant (Elhassan), Department of Civil and Environmental Engineering, University of Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249
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  • Subash Yeggina,

    1. Graduate Research Assistant (Yeggina), Department of Civil Engineering, Indian Institute of Science, Bangalore, India 560012
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  • Almoutaz Elhassan

    1. Respectively, Graduate Research Assistant (Chintalapudi), Assistant Professor (Sharif), and Graduate Research Assistant (Elhassan), Department of Civil and Environmental Engineering, University of Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249
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  • Paper No. JAWRA-11-0146-P of the Journal of the American Water Resources Association (JAWRA). Discussions are open until six months from print publication.

(E-Mail/Chintalapudi: nok880@my.utsa.edu).

Abstract

Abstract:  The main objective of the study is to examine the accuracy of and differences among simulated streamflows driven by rainfall estimates from a network of 22 rain gauges spread over a 2,170 km2 watershed, NEXRAD Stage III radar data, and Tropical Rainfall Measuring Mission (TRMM) 3B42 satellite data. The Gridded Surface Subsurface Hydrologic Analysis (GSSHA), a physically based, distributed parameter, grid-structured, hydrologic model, was used to simulate the June-2002 flooding event in the Upper Guadalupe River watershed in south central Texas. There were significant differences between the rainfall fields estimated by the three types of measurement technologies. These differences resulted in even larger differences in the simulated hydrologic response of the watershed. In general, simulations driven by radar rainfall yielded better results than those driven by satellite or rain-gauge estimates. This study also presents an overview of effects of land cover changes on runoff and stream discharge. The results demonstrate that, for major rainfall events similar to the 2002 event, the effect of urbanization on the watershed in the past two decades would not have made any significant effect on the hydrologic response. The effect of urbanization on the hydrologic response increases as the size of the rainfall event decreases.

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