Existing comment:
The Spillway
When properly designed and maintained, dams made of earth can hold back huge bodies of water. However, water must never be allowed to run over the top of an earth dam. Running water can rapidly erode an embankment, causing a dam to give way. It was this "overtopping" the doomed the South Fork Dam.
The dry, rocky channel in front of you was the dam's spillway. Designed to prevent overtopping, it should have allowed excess water to escape during floods. Why didn't it save the dam?
- The spillway was not wide enough or deep enough to handle the flow which increased dramatically after the heavy rains.
- The spillway was the only outlet. Pipes and valves originally installed at the base of the dam to release water had been removed.
- Heavy metal screens had been fixed to the bottom of the spillway bridge to keep game fish from escaping. The screens impeded the water.
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