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.