Lessons from a Dam Failure

The IVEX Dam (Chagrin River, northeastern Ohio) failed catastrophically on 13 August 1994, releasing 38,000 m3 (about 10 million gallons) of impounded water and sediment. This event was triggered by a 70-year rainfall event (13.54 cm of rainfall within 24-hours), resulting in flows 1.9 m above the top of the spillway and impinging on the top of the dam. The failure was the result of seepage piping at the toe of the dam, near the masonry spillway-earthen dam contact. Eyewitnesses reported that collapse of the seepage pipe created a breach in the dam that rapidly downcut. Paleohydrologic modeling suggests peak discharge through the breach was about 466 m'sec1, substantially dewatering the reservoir in approximately 2-3 minutes.