DWSM, the dynamic watershed simulation model, was expanded with a subsurface and a reservoir flow routing schemes. The hydrology and sediment components of the model were applied to three agricultural watersheds in Illinois, Big Ditch (100 km2), Court Creek (250 km2), and Upper Sangamon River (2,400 km2), to simulate spatially and temporally varying surface and subsurface storm water runoff, propagation of flood waves, upland soil and streambed erosion, and sediment transport; to evaluate these simulation capabilities through calibration and validation; and to conduct various watershed investigative analyses. The new schemes were selected from the literature. DWSM was able to simulate the major hydrologic, soil erosion, and sediment [...]