The Importance of Flood Routing

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Flood routing is a key element in hydrologic analysis, but one that is often overlooked. Civil engineers, hydrologists, and conservationists all need to be ready to use flood routing as an analytical tool when dealing with any river system that might have its flood profile altered by proposed or ongoing projects. By performing flood routing, one can enhance safety and efficiency while reducing environmental impact.

Flood routing is crucial in:

  • Flood forecasting
  • Flood protection
  • Reservoir design
  • Spillway design

While there are several different approaches to flood routing, they fall broadly into the categories of hydrologic routing and hydraulic routing, the former being more common than the latter. Hydrologic routing depends upon the equation of continuity. On the other hand, hydraulic routing combines both the continuity equation and the equation of motion for unsteady flow.

What is Flood Routing?

During flood routing, the civil engineer models a flood wave to understand its behavior at the different points along a waterway. Today, advanced computer software is used to develop very sophisticated models, taking into account variances in precipitation and other factors. However, it is also possible for researchers to perform many of the key calculations by hand. Even though water may seem to behave in very complicated ways, that behavior is ultimately predictable.

Why is Flood Routing Important?

Flood routing is used in a wide variety of different applications:

Reservoir Management

Many communities rely on reservoirs to supply their water needs. In order for reservoirs to be effective, they must experience periodic high water volumes. Engineers must be able to predict how the reservoir will respond under these conditions, maximizing the usage of the water while preventing dangerous floods. Engineers use flood routing to decipher whether community needs will be met, whether outflow is needed, and how water management strategies should be adjusted.

Environmental Stewardship

Flood routing can be used as one tool for understanding how precipitation and other conditions affect the waterway as a whole. For example, it can help researchers to understand how weather patterns and other environmental factors affect the plants and animals who rely on the river environment. Flood conditions and other cyclical changes in waterway behavior often have a profound impact on erosion, which scientists must be aware of to plan their conservation efforts.

Flood Preparation and Response

Many towns and cities throughout the United States are prone to some degree of flooding. Even if flooding is rare, the conditions that could cause it may arise with very short notice. Before the danger materializes, hydrologists can use flood routing to understand the potential effects – and what steps should be taken in preparation. This can reduce the risk to lives and property. It can also provide information to others, such as epidemiologists, to safeguard against related public health risks.


Effective agriculture often depends to a great extent on being able to predict and respond to the behavior of a waterway. Farms and ranches that might be subject to flooding need to be able to protect crops and take appropriate action before, during, and after a flooding event. Just as it was along the ancient Nile River, many agricultural concerns also depend upon periodic flooding or unusual heavy precipitation to make their crop yields possible. Still, flood routing provides additional knowledge and security to keep people out of danger in difficult conditions.

Flood routing is just one of many tools a hydrologist uses to understand the environment – but it is of critical importance. In the private sector, state governments, and at the federal level, experts in flood routing provide vital information. As weather and climate patterns continue to adjust over time, flood routing is sure to remain one of the most important tools for monitoring the health of waterways.

Learn More

Civil engineers play a crucial role in engineering the structural solutions of tomorrow and plan, design, construct, and operate the infrastructure essential to our modern lives. As a student in the online Master of Science in Civil Engineering program, you can enhance your quantitative decision-making skills and learn how to justify managerial decisions with data. You will also explore the capabilities of modern management technologies and discover how to successfully leverage these tools to maximize efficiencies in your projects and on your teams.