Abstract The movement of water on the land surface, within channels and through the soil is dependent on some hydrological factors. For surface flow, the velocity of flow increases with the bottom gradient of the channel and the flow depth, but when roughness increases, it decreases. For a given flow depth, the velocity decreases as the channel height increases. The construction of sub-surface drainage helps to remove excess soil water that can cause flood. To model overland flow, a kinematic-wave approach is applied so that flood prediction could be made.