Hydrologic simulation is an important process for better understanding the spatial and temporal distribution of water resources at any watersheds. Three hydrological models with different structures and spatial capabilities were selected to simulate at three small to large watersheds; Providence/Kings River (4.55 km2), Susquehanna River (71,230 km2), and Congo River (3.7 million km2). First, the Regional Hydro-Ecological Simulation System (RHESSys) model applied at Providence watershed to analyze impacts on key elements of the hydrologic cycle affected by forest harvesting – snowpack accumulation, ablation, transpiration, and streamflow. Second, Hillslope River Routing (HRR) model coupled with Variable Infiltration Capacity (VIC) model applied at Susquehanna River Basin for streamflow simulation using in situ measurements. Third, three satellite derived precipitation datasets (TRMM, CMORPH, and PERSIANN) are used to drive HRR model in the Congo River Basin. Due to limited in-situ measurements in Congo River Basin, the model outputs were validated using water surface elevations derived from ENVISAT laser altimetry data and monthly water storage values derived from GRACE data. This presentation will address the issues associated with hydrological simulation for small scale to large scale watersheds and focus on approach for streamflow simulation for the watershed with limited in-situ measurements using remotely sensed data. Finally, landslides analysis using remotely sensed data will be briefly discussed.