Changes in Runoff as a Result of Wildfires

State dam safety program responses to the following inquiry:

State seeks information regarding the evaluation of the potential changes in run off as a result of wildfires and dam design. In particular we’re wondering if any other states evaluate the potential change in runoff after a fire event while reviewing the design of the dam. There are numerous studies showing the potential increase in run off after a fire event due to the loss of vegetation and the effects of ash. As we continue to evaluate our recent failures at the Wenner Lakes Dams from back in August, we’re calculating runoff similar to 1/1000 year storm event even though the actual storm was about a 1/5 year storm event. Specific questions:
• Any dam incidents after a forest fire in their watershed? If so, how did the fire contribute to the incident? How was a failure averted?
• Any dam failures after a forest fire in their watershed? If so, how did the fire contribute to the failure?
• Any policies or protocols for dam operations and/or emergency action planning after a forest fire in their watershed?
• Any policies or protocols for spillway designs for dams in fire-prone watersheds?

The ASDSO surveys archive is available to members through the members only section of DamSafety.org