Hydrologic Engineering Center-Hydrologic Modeling System model is used to estimate the water storage in the lakes of three dams due to rainfall events in three wadis located in the northern area of the United Arab Emirates (UAE). Like other arid and semiarid regions, rainfall events in the three wadis are limited, scattered, and random. For model calibration, the simulated results were compared with the observed water storage data for several storm events. A family of rainfall-runoff/storage curves was developed based on the duration and intensity of rainfall events. These curves can be used for prediction of surface water runoff in the three wadis and water storage in the dams in response to different rainfall events. The same rainfall event in wadi Bih generates almost twice as much of the surface water runoff generated in each of wadi Ham and wadi Tawiyean. This is mainly attributed to the large catchment area of wadi Bih as compared to the other two wadis. The sensitivity analysis revealed that the amounts of water storage in dams are highly correlated to the assigned curve number especially for the cases of wadi Bih and wadi Tawiyean.