Mathematical (hydraulic) models for rivers, channels and sewerage systems are perhaps the most widely used types of modelling codes available to water authorities and their consultants. They have proven to be important tools for investigating and predicting the in-stream flows, travel times, and water level variations in rivers, channels and canal systems. As floodplains have become preferred areas for habitation, floods have increasingly adverse impacts on economic activities and result in loss of life and property. An accurate and reliable flood analysis, management and flood forecasting provide, therefore, important bases for mitigating flood hazards and issuing early warnings. In recent years, instream hydraulic model codes and real-time simulations have been important instruments for the above issues.

(GWP 2013b)