Mill River Dam Deteriorates, Downtown Closed

If the dam breaks, does this story represent an engineering failure? Is it reasonable to expect such a structure to withstand 16+ inches of rain in an eight-day period? Does this much rainfall represent an extraordinary event that none could anticipate? Comments, please.

Any time a dam breaks its a failure, although not necessarily an engineering one. I'd consider the following "engineering failures":

* Design flaws
* Using improper benchmarks or risk/benefit analysis
* Using substandard materials
* Neglect of general upkeep or necessary repairs

Of course many of these can be enhanced or caused by "political failures" - most notably economic cutbacks, limitations on the plan for economic reasons, or lack of upkeep due to cost.

To answer the primary question though, I don't think it would have been unreasonable to expect 16 inches of rain over 8 days. But I, of course, know the end result so I'm not sure what I would have said a month ago. I can just as easily say that the New Orleans leeves should have been 50 feet thick and 100 feet tall...

Moose, your first link doesn't seem to work.

An additional 16" of water is equivalent to a pressure increase of 83 pounds per square foot over the face of the dam. If that is enough to cause the dam to collapse, then the safety factor was not adequate in the first place. That may be deemed to be a design failure.

Can't they release the water at a faster rate to mitigate the problem?