Flood prevention includes the measures installed to prevent or reduce damages caused by floodwater. Flood prevention is further defined as the control and disposal of surface water caused by abnormally high direct precipitation,stream overflow, or floods aggravated or caused by wind or tidal effects. Where completed watershed projects are in place, damages from natural disasters are greatly reduced.
A variety of measures are used for flood protection in watershed projects. Some are larger, more complex and often costly practices that require group action to plan, install, operate and maintain. Structural measures might include levees, dikes, floodways, floodwater diversions, and flood control dams. Other measures can also be used to reduce the impacts of flooding. These may include regulatory measures such as land use zoning and enforcement of building codes, as well as relocation of structures, flood proofing buildings, land acquisition, and preparing emergency action plans and flood warning and response systems.