The Soil Moisture Water Balance Model (SMWBM) is designed for daily catchment rainfall runoff simulation, catchment water balance accounting and soil moisture accounting.  SMWBM is a semi-deterministic model based on the algorithms of Pitman (1967), who originally developed the model to simulate river flows in South Africa. Model functionality has been extended by WWA to incorporate hourly calculation during rain days, a surface ponding function, daily evaporation, evaporation functions for differing land cover, vadose zone (unsaturated) flow and travel time functionality, along with UI tools for model calibration (hydrographs and flow duration curves), calibration statistics (NSE, PBIAS, etc.), water balance reporting and flow statistics.