Lessons Learned

Gates and other mechanical systems at dams need to be inspected and maintained.

Hazardous hydraulic conditions, such as hydraulic rollers, can occur at dams of all sizes.

High and significant hazard dams should be designed to pass an appropriate design flood. Dams constructed prior to the availability of extreme rainfall data should be assessed to make sure they have adequate spillway capacity.

High and significant hazard embankment dams should have internal filter and seepage collection systems.

Intervention can stop or minimize consequences of a dam failure. Warning signs should not be ignored.

Many earth-cut spillways have been constructed in erodible material that can result in unsatisfactory performance and breaching of the spillway

Natural dams can form quickly through processes such as landslides, avalanches, and river ice jams. In some cases, the formation of natural dams requires prompt intervention to protect people and property.

Past successful dam performance does not guarantee future successful performance.