Abstract
Flood hydrograph determination under arid climate for countries like Saudi Arabia is essential for the assessment of water resource potential and for the design of various hydraulic structures. To meet such objectives, hydrological and morphological data from different regions of Saudi Arabia are evaluated for their suitability and tested for model application. The suggested model used in the present study, geomorphologic instantaneous unit hydrograph (GIUH), is applied by the researchers for its application in the selected thirteen representative basins. The calibrated model for gaged wadis can be applied to other ungaged wadis by following the proposed procedure. The mathematically and graphically derived relations are found to be the key elements in the prediction of flood hydrographs for ungaged wadis.