This document discusses hydrological modeling of the Penganga sub-basin in India using the ArcSWAT model. It provides background on the hydrological cycle and importance of hydrological modeling. The study aims to simulate stream flow in the Penganga river to help water resource managers. Input data on soil, climate and land use were generated from GIS. The basin was delineated and hydrological response units were defined in ArcSWAT. The SWAT model was calibrated and validated, with results found to satisfactorily represent the hydrological regime of the sub-basin. The calibrated model can be used to inform future water resource management in the area.