Lessons Learned

Dams located in seismic areas should be evaluated for liquefaction, cracking, potential fault offsets, deformations, and settlement due to seismic loading.

Dams should be thoroughly assessed for risk using a periodic risk review process including a site inspection, review of original design/construction/performance, and analysis of potential failure modes and consequences of failure.

Downstream flooding can be caused by spillway flows that exceed channel capacity or as a result of reservoir misoperation.

Downstream of constructed spillway exit channels, spillway outflows can erode and even breach dam embankments and can adversely impact the operation of outlet works.

Dozens of dams can fail or be in danger of failing during a single event (i.e. swarming failures). Dam owners and regulators need to prepare for these types of events.

Drum gates are complex mechanical systems that must be carefully operated and maintained.

Early Warning Systems can provide real-time information on the health of a dam, conditions during incidents, and advanced warning to evacuate ahead of dam failure flooding.

Earth and rockfill embankment dams must be stable under the full range of anticipated loading conditions.