Flood routing is the process of modeling a flood wave to understand what it will do at various points along a waterway. This is critical for reservoir and waterway management and can also become important in an emergency when accurate flooding forecasts are necessary to determine whether a flood poses a risk to health and safety. Software programs can perform flood routing, and it is also possible to do calculations by hand.
Water behaves in predictable ways that can be modeled by researchers who understand the dynamics of water, waterways, and flood behavior. In a flood, a very high volume of water moves through established waterways and may spill out onto neighboring land. With information about how much water is present and the physical characteristics of the region, an engineer can perform some flood routing equations to make predictions about the movement of the flood.
In reservoir management, engineers rely on periodically high volumes of water to recharge the reservoir and provide adequate water supplies for the community. They use flood routing to determine if a flood will meet the need and to check for signs that they need to make adjustments to the reservoir or their water management plans. It may be necessary to open the spillway on a dam for outflow, for instance, to prevent overload as the flood waters move in.
Hydrologists concerned with waterways and environmental health can use flood routing and other modeling tools to predict situations and collect information about ongoing flood conditions. This information may also help with erosion predictions. The hydrologist wants to be able to model the shape of the wave, as this can have important implications for how it moves, along with the height and the timing. It can be important to know when flood waters should crest and recede.
Another use for flood routing is in modeling for health and safety reasons. It can take time to get an evacuation order and to ensure that everyone in a community complies. In conditions where a flood may occur, hydrologists perform calculations to make predictions and determine if an evacuation is recommended. They may also suggest sheltering in place or other safety measures to reduce the loss of life or property.
Government agencies rely on hydrologists to perform flood routing tasks. They can also work in private industry, particularly industries like agriculture, where accurate flood forecasting is very important. Insurance agencies also have a use for flood modeling, as they use this information when they issue policies and pay out on claims.