The Performance of Physically Based and Conceptual Hydrologic Models: A Case Study for Makkah Watershed, Saudi Arabia

Population growth and land use modification in urban areas require the of accurate tools for rainfall-runoff modeling, especially where topography is complex. The recent improvement quality resolution remotely sensed precipitation satisfies a major need such tools. A physically-based, fully distributed hydrologic model conceptual semi-distributed model, forced by satellite rainfall estimates, were used to simulate flooding events very arid, rapidly urbanizing watershed Saudi Arabia. Observed peak discharge two flood was compare hydrographs simulated models, one calibration validation. To further explore effect heterogeneity, produced three implementations compared against each other output physically-based model. results showed ability models capture complex variability soils watershed. In general, GSSHA required less performed better than HEC-HMS. This study confirms that HEC-HMS cannot be without calibration, while can best option case lack data. Although good agreement at point, there significant differences runoff, discharge, infiltration values interior points