Why Assess Risk?

It is important to know how levees are expected to perform and what the potential consequences of non-performance would be – in other words, to place levee systems in a risk-informed context.  The essential questions are:

• What possible loading events (flood, storm, earthquake, etc.) could occur?
• How will the levee perform when subjected to these events?
• What are the consequences if the levee doesn't perform well – in particular, what loss of life could occur?

Putting levees in a risk context is a consistent and credible way to prioritize actions in a time of constrained resources. USACE plans to use risk assessments to prioritize life safety risks for its own levee safety activities, and also to provide a basis for communicating risk so levee sponsors and other stakeholders can make more informed decisions.

USACE quantifies flood risk associated with four scenarios as shown below.