Long-term InHM simulations of hydrologic response and sediment transport for the R-5 catchment

The physics-based model known as the Integrated Hydrology Model (InHM) is used to simulate continuous hydrologic response and event-based sediment transport for the R-5 catchment (Oklahoma, USA). For the simulations reported herein the R-5 boundary-value problem was refined, from that reported by Loague et al. (2005), to include (i) an improved conceptualization of the local hydrogeologic setting, (ii) a more accurate topographical representation of the catchment, (iii) improved boundary conditions for surface-water outflow, subsu rface- water outflow and evapotranspiration, (iv) improved characterization of surface and subsurface hydraulic parameters and (v) improved initial conditions. The hydrologic-response simulations were conducted in one-year periods, for a total of six years. The sediment-transport simulations were conducted for six selected events. The multi-year water-balance results from the hydrologic-response simulations match the observed aggregate behavior of the catchment. Event hydrographs were generally simulated best for the larger events. Soil-water content was over-estimated during dry periods compared with the observed data. The sediment-transport simulations were more successful in reproducing the total sediment mass than the peak sediment discharge rate. The results from the effort reported here reinforce the contention that comprehensive and detailed datasets are crucial for testing physics-based hydrologic-response models. Copyright (c) 2007 John Wiley & Sons, Ltd.