One main natural hazard resulting from interactions between rainfall-runoff is flooding. Extreme precipitation causes surface water flow to rise, hence breaking river systems and causing flooding. This work models and forecasts flood dynamics in the Kunhar River basin with the Hydrologic Engineering Centre's Hydrologic Modelling System (HEC-HMS). It shows how well the technology can combine several hydrological data points to precisely project flood paths. These studies have repeatedly shown the dependability of HEC-HMS over many geographical and climatic environments, therefore confirming its fit for thorough hydrological research. HEC-HMS included obtaining thorough datasets comprising historical hydrological data from NASA, spatial information from ARCGIS, and meteorological data from WAPDA in addition to flow rates and water levels. We started the basin model in HEC-HMS by including Digital Elevation Models (DEMs) to define watershed boundaries and record topography. Terrain preprocessing came next to solve discontinuities and guarantee correct water flow modelling. Combining several datasets, the model was designed to reflect the coordinate system and underwent hydrological study to replicate surface water flow, accumulation, and stream networks inside the basin. With subbasin-10 showing the largest peak flow of 132 cubic meters per second during severe rainfall events, especially on August 7, 2013, results revealed that HEC-HMS effectively forecasted peak discharges in the subbasins of the Kunhar River. With an estimate 90% accuracy rate, this proved the great dependability of HEC-HMS in flood prediction. The results show that the model can help with flood management planning and foresee flood circumstances. HEC-HMS's value in designing flood barriers and enhancing watershed management particular to each subbasin. It emphasizes the need of revised hydrological models to consider land use and increasing temperature.