In this project a gravity dam was designed across wadi Banban north of Riyadh city. The dam was designed for flood control where a total of more than one million cubic meter of water were detained. In order to assure an effective flood control, five outlets were provided. These outlets allow stored water to be discharged within one day keeping the dam empty for the next flood and smoothing the flood hydrograph over a longer duration. Designed dam was checked for stability condition and found safe for the loading combination used.