Depression threshold control proxy to improve HEC-HMS modeling of depression-dominated watersheds

ABSTRACT

Many hydrologic models utilize delineation results from traditional methods which create a hydrologically connected drainage system. In depression-dominated areas, topographic characteristics of depressions are vital to modeling unique hydrologic processes associated with puddle-to-puddle (P2P) filling-spilling dynamics. The objective of this study is to evaluate the impacts of the P2P processes and dynamic changes in contributing area on outlet discharge. To do so, an improved HEC-HMS model is developed by incorporating a depression threshold control proxy (DTCP) and an improved conceptual framework. The DTCP uses a storage–discharge function to simulate the P2P dynamics. The improved conceptual framework counteracts the effect of full hydrologic connectivity created by traditional delineation methods by introducing depressional and non-depressional areas to each sub-basin. Application of the improved HEC-HMS model demonstrated that it was capable of accurately simulating outlet discharge and providing the details on surface connectivity and depression storage.