Feds revoked failed Midland Michigan dam's license in 2018 over inability to handle big floods

[DrQ]

One of the problem with earth dams are burrowing animals. If you don't keep on top of them, they will make swiss cheese of the retaining wall.

 

[Steve Fatula]

Sounds like I should be glad we have real dams here. Army corps rules!

 

[DrQ]

We have our own "troubled dams" in the DFW area:

Lewisville Dam: The dam called trouble

The Army Corps of Engineers will need millions of dollars to repair the Lake Lewisville Dam, one of the nation’s most dangerous. A breach could put 431,000 people in harm’s way.

interactives.dallasnews.com

But the only mussels they give a dam about are zebra mussels.

 

[T_R_Oglodyte]

One of the problem with earth dams are burrowing animals. If you don't keep on top of them, they will make swiss cheese of the retaining wall.

At first glance, that doesn't appear to be the immediate cause of failure. Holes created by burrowing animals most often lead to piping failures. Water begins to flow through the hole, then washing out and enlarging the hole.

Looking at the video, there were more problems with the dam than just the spillway capacity. The dam did not fail from overtopping, though overtopping may have been the initiating event. It failed structurally. The toe of the dam was unable to resist the horizontal pressure imposed by the full-to-the,brim reservoir. That involves combinations of toe drainage system, width of the base, keying of the foundation into underlying materials, and other items.

That's not to say that burrowing animals wasn't a major factor. For example, if there were animal burrows on the upstream face of the dam, near the typical water line, water could invade the core of dam through the burrows. If the drainage system were unable to remove that volume of water, the added bouyancy of the water would reduce the ability of the dam to withstand horizontal pressure.