393670 - A New Model for Rainfall-runoff Simulation in Depression Dominated Areas
Thursday, June 7
10:30 AM - 12:00 PM
Location: Skyway Room
North Dakota State University
Xuefeng Chu, Dept 2470, PO Box 6050 Fargo, ND 58108-6050 – North Dakota State University
Depressions, which break the continuity of hydrologic processes and delay generation of surface runoff, are nonnegligible for simulation of rainfall-runoff processes in depression dominated areas. Instead of flowing to an outlet directly, surface runoff fills depressions first and then drains to the outlet. However, in traditional methods depressions are often fully filled, which fails to reflect the influences of depressions on rainfall-runoff processes. Though there are some functions to account for depressions in some models, it is difficult to quantify the dynamic depression storage changes and the associated threshold control of water release. To simulate hydrologic processes under the influence of surface depressions, a new semi-distributed, depression-oriented model (HYDROL-D) was developed. In HYDROL-D, a watershed is divided into a number of subbasins, each of which is further divided into a non-depressional area (NDA) and a depression area (DA). Each DA includes a contributing area (CA) and a ponding area (PA). A depression-dominated delineation (D-cubed) algorithm was used to delineate surface depressions and calculate topographic parameters, including maximum depression storage and maximum ponding area for each depression. The results from the D-cubed algorithm were processed and utilized in HYDROL-D to determine the ratios of NDA and DA, the dynamic CA-PA relationships for all DAs, and the water release thresholds of all PAs. HYDROL-D and the widely used HEC-HMS were applied to a watershed in North Dakota, and the simulation results for four modeling scenarios were compared against the observed data. The results indicated that HYDROL-D with multiple water release thresholds had a better ability to effectively simulate hydrologic processes influenced by surface depressions.