Title: Comparing influence of combinations of precipitation loss and rainfall excess-runoff transform models to flood flow rate in a flatland watershed

Authors: Zhiyong Duan; David C. Froehlich

Addresses: Bechtel Corporation, 3000 Post Oak Blvd Mail Stop 19, Houston, TX 77056, USA. ' Bechtel Corporation, 3000 Post Oak Blvd Mail Stop 19, Houston, TX 77056, USA

Abstract: Hydrologists can use many different precipitation loss rate functions and rainfall-excess transform techniques to develop watershed runoff hydrographs. For the most part, they can apply the loss and transform approaches in nearly any combination. To evaluate some of the many possible groupings, we formed a matrix of three commonly used precipitation loss rate models and three rainfall-excess runoff transform models, and compared the simulated runoff hydrographs for a single large storm. Peak flow rates predicted by US Geological Survey (USGS) regression equations were compared to those calculated by the various loss-rate/excess-transform models. Parameter estimates of the precipitation loss functions and rainfall-excess transform models were also analysed. The combination of the Natural Resources Conservation Service (NRCS) curve number (CN) loss-rate function and the NRCS unit hydrograph (UH) model was found to be best option because it requires simple parameters that can represent watershed characteristics adequately. The other combinations also have reasonable predictions. However, the estimate of some of their parameters brings in uncertainty in predictions.

Keywords: runoff hydrographs; precipitation loss; rainfall excess runoff transform; modelling; flood flow rate; flatland watersheds; simulation; hydrology.

DOI: 10.1504/IJHST.2012.045937

International Journal of Hydrology Science and Technology, 2012 Vol.2 No.1, pp.22 - 33

Published online: 16 Aug 2014 *

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