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"But, even though they pose little danger in the event of a breach, low head dams create a public safety issue that has caused more fatalities in the U.S. than
by mauvehaus 5y ago
"But, even though they pose little danger in the event of a breach, low head dams create a public safety issue that has caused more fatalities in the U.S. than all dam failures in the past 20 years."
Good article generally, but that's a super misleading statistic, or at least easily cherry picked to support a point. Dam failures in general are pretty rare, and fatal ones are even rarer.
Imagine if there was a bad but not Johnstown level fatal dam failure 25 years ago. You can tell two radically different stories if you choose to compare deaths over the last 20 years vs last 30.
The author's point would be more convincingly made if they talked about fatal dam failures over time and demonstrated that they had nothing up their sleeve before making that comparison.
Incidentally, you get naturally occurring keepers as well. I'm not privy to the full details but there was a drowning in the BWCA in 2002. AIUI somebody took a dip in a hydraulic below a falls along Horse Portage and wasn't able to escape. They went through too many times and could not be resuscitated. As I understand it, they were pulled out in an extremely risky and improvised rescue attempt, but it was too late for the victim.
- greenie_beans 5y agoThe writer links to some data at the end: https://krcproject.groups.et.byu.net/browse.php https://krcproject.groups.et.byu.net/browse.php. Do you know of any other data they could use or ?
- pge 5y agoI agree that comparing low head dams to dam failures is a weird comparison, so here’s a different one - on average about 10% of fatalities on moving water (ie rivers) are caused by low head dams (source: American Whitewater). That’s a lot. As you note, hydraulic jumps occur naturally (and that’s what makes whitewater kayaking fun!), and deaths do occur on natural holes as well. Naturally occuring recirculating holes, however, are not as deadly as low head dams because they are rarely as uniform or as wide. There’s usually something that breaks up the flow or a place from which rescuers can reach the victim with a rope. Dams are typically wide and smoothly uniform across the width of the river leaving no place to escape. Whitewater boaters (the people most likely to come across natual hydraulics) learn early how to distinguish the fun hydraulics from the scary ones. It’s usually inexperienced boaters that see the small drop of a low head dam and think it looks like a fun ride.
- denimnerd42 5y agoYeah I didn't like that bit either. Sounds misleading given how rare dam failures are.