"Lost control of the project?"

I mean, it's not like they're just letting a schedule slip past a due date or something.

So, if more of Nashville were to be inundated, would that have been an "involuntary wetlands conversion?"

BTW: Wife is in Bellevue as volunteer relief as we speak. Her words - "heartbreaking."

Is lost control of the project synonymous with overtopping the dam? Maybe it's a larger category.

Surely they didn't mean the dam would have failed, although the link did mention the need to draw down to a safe level. I think they meant that they would no longer have the ability to mitigate downstream flow, which at 451.4 was pretty much true already.

But I'm obviously guessing and I hope someone can give an authoritative answer.

I ain't no engineer, but I seem to recall reading somewhere that if water overtops a dam for very long it can undermine the bottom structure/foundation on the downstream side which can weaken it enough to pose a risk of breach.

But in this case I read "loss of control" to mean "involuntary wetlands" downriver.

There are tons of variables here but overtopping a dam tends to lead to an erosive failure from the top down. The failure can be partial or total and there are a number of forces that can be unleashed into a number of failure scenarios. Dams are constructed with spillways to alleviate this to a point, but once the water reaches a given level at a reservoir systems and engineering are overwhelmed and events can cascade on their own with catastrophic consequences.

The Johnstown Flood was the result of the overtopping of the South Fork Hunting and Fishing Club's dam during a heavy rainfall event in May, 1889. It was an earthen dam and all means of lowering the water levels had been removed years before the collapse. The spillway was also clogged as debris collected on a barrier that was installed to keep the club's stock of fish from escaping the lake.

UPDATE: TVA doubts system would have handled the event here.

Also according to the article, the Corps says if Hickory had overtopped it would have added four more feet of water to the flood in Nashville.

I don't buy that this was a 1000 year flood event without knowing a lot more. It was only 12 feet above flood stage.

Some of the flood's severity may be related to sprawl, which creates impermeable surfaces. The rampant and un-checked replacement of woods with pavement, roofs and lawns(which allow about as much infiltration or rainwater as pavement) is a recipe for flooding.

In the past few decades Nashville has become one of the most sprawled out cities in the US, so its not surprising that we're now seeing intensified flooding there.