AbstractArid regions generally lack surface water records for developing flood characteristics for hydraulic design purposes. Consequently good records of floods, particularly large ones, are a data asset to arid zone hydrology.A large rainfall and runoff event which occurred on 23 April 1985 has been fully recorded on Wadi Ghat, a 597 km2catchment in southwest Saudi Arabia.Maximum point rainfall intensity was 115.4 mm hr−1. The peak discharge was 3200 m3s−1. Point rainfall has an expected frequency of occurrence in excess of once every 200 years. The peak discharge is expected to occur on an average once in 143 ye