Topmodel for streamflow simulation of a tropical catchment using different resolutions of ASTER DEM: optimization through response surface methodology

The unavailability of proper hydrological data quality combined with the complexity of most physical based hydrologic models limits research on rainfall-runoff relationships, particularly in the tropics. In this paper, an attempt has been made to use different resolutions of DEM generated from freely available 30 m-based ASTER imagery as primary input to the topographically-based hydrological (TOPMODEL) model to simulate the runoff of a medium catchment located in the tropics. Response surface methodology (RSM) was applied to optimize the most sensitive parameters for streamflow simulation. DEM resolutions from 30 to 300 m have been used to assess their effects on the topographic index distribution (TI) and TOPMODEL simulation. It is found that changing DEM resolutions reduces the TOPMODEL simulation performance as the resolutions are varied from 30 to 300 m. The study concluded that the ASTER 30 m DEM can be used for reasonable streamflow simulation of a data scarce tropical catchment compared with the resampled DEMs