SENSITIVITY ANALYSIS OF HEC-HMS HYDROLOGIC MODEL TO THE NUMBER OF SUB-BASINS: CASE STUDY

摘要

This paper presents a sensitivity analysis of the hydrologic model HEC-HMS to thenumber of sub-basins for the McDonald Creek watershed in Huntsville, Alabama.ArcGIS was used to estimate the parameters needed for the model. The sensitivityanalysis of HEC-HMS runoff results was evaluated for two cases, namely, Case 1 andCase 2. The number of sub-basins of the watershed was 3 and 5 for Case 1 and 2,respectively. This study implements kinematic wave method to model the overlandflow transform and Muskingum-Cunge method for channel routing. The loss rate wasestimated using both Green-Ampt and SCS curve number methods. The resultsdemonstrated that the number of sub-basins did not significantly affect the dischargeresults. However, increasing the number of sub-basins changed the discharge peakvalues. The results also showed that HEC-HMS model was sensitive to the inputslope parameter when the SCS method was used, while it was not in case of using theGreen-Ampt method.