In Detail: Recommended Practice - Flood Hazard Mapping

Flood extent information is used for damage assessment and risk management. Moreover, the coordination of emergency activities during flood events can be positively affected by the correct use of flood extent information. It is also very important for calibration and validation of hydraulic models to reconstruct what happened during the flood and to determine and monitor the extent of flooded areas, providing a quantifiable estimate of the land area and infrastructure affected by flooding.  Flood prediction and modeling generally involve approximate descriptions of the rainfall-runoff transformation processes. These descriptions are based on either empirical, or physically-based, or combined conceptual physically- based descriptions of the physical processes involved. Although, in general, the conceptualizations may neglect or simplify some of the underlying hydrologic transport processes, the resulting models are quite useful in practice because they are simple and provide adequate estimates of flood hydrographs. GIS is powerful tool in water resources applications like flood risk assessment and mapping at various scales. Hydrologists use GIS technology to integrate various data and applications into one manageable system.