Every once in a while someone posts a thread about the dangers of low head dams. Dale Briggs just uploaded a video of a resuce in Dayton that illustrates the risks well.
http://www.youtube.com/watch?v=GcfIDj5cAZA&feature=g-all-u
Low head dams look innocuous. But they are perfectly constructed, solid-state killing machines. These folks went rafting once or something and thought it would be a hoot to run the dam. Don't ever do it.
This
type of thing happens all too frequently in the boating world. It was one of the cautions I just received from river boat captains regarding my trip down the Ohio river. They made it quite plain to stay away from these things.
Every Gallon weighs 8 Pounds
Imagine getting pummeled by millions upon millions
of full; plastic 1 gallon milk jugs; relentlesslly;
never ending, and use human strength to escape;
- it simply cannot be done.
If you see an ""Infinity Pool"" looking Flat Line
on the horizon of the river - EXIT the river quickly;
and walk around.
To gain a better understanding of what
really happens when water rushes over
obstacles in the river.
http://serc.carleton.edu/details/files/19075.html
http://serc.carleton.edu/details/files/19076.html
http://bit.ly/RocksWaterFlow
First time I really understand what a
“Low Head Dam” really is and why it’s a danger. Thanks again Pnet!
And if you do…
…decide to run a dam, don’t do it with beach toys 
Apparently not just for
newbies as I believe the woman comments that they made the decision to do this based on their whitewater experience.
A minor miracle
that those rescues weren’t recoveries.
riskiest kind of newbies
I’ve run into a lot of folks with similar mindsets as that woman - they’ve taken a raft trip or two somewhere like the Yough, New, Ocoee, etc., or perhaps they fumble their way successfully down a float stream in a rental canoe every summer, and it makes them think that they are “experienced” paddlers. Can’t really fault them for not knowing what they don’t know, but it can be a recipe for trouble.
beach toys vs boats
I think they may have survived at least in part due to the fact that they were using beach toys instead of boats. Those tubes were light enough and apparently shaped just right to end up in a stable surf instead of swamping and getting repeatedly cartwheeled/maytagged. As a result, the victims had something to hang onto that kept them out of the usual recirculation cycle.