Exploiting the topographic information in a PDM-based conceptual hydrological model

In this work, a conceptual lumped model was developed to simulate runoff and analyze hydrological processes with the goal of incorporating the morphological information into a probability-distributed model (PDM). PDMs usually describe the process of runoff generation as the result of soil saturation excess caused by precipitation with soil storage capacity represented by a spatially distributed quantity and described by a probability distribution. The proposed model, called topography-based probability distributed model (TOPDM), based on a simple water balance whose components are basin soil moisture storage, precipitation, drainage to groundwater, evapotranspiration, and Dunnian and Hortonian surface runoff, is the result of the combination and integration of the topographic index within a PDM. A TOPDM was applied to the Baron Fork basin in Oklahoma in this research, and simulation results show that it provides a reasonably good estimation of runoff and a realistic representation of physical process in the catchment confirmed by the comparison with soil moisture data and with the results provided by a more complex, physically based distributed hydrological model.