Video for New Paddlers: Low Head Dams

This is classic way to die . Fortunately he got out of it more by luck than knowing what to do.



http://www.youtube.com/watch?v=T0dD1yz9Gtw&feature=channel_page




Kind of confusing… He screws up the
first time, but swims out. Then for some reason he runs again and lucks through. And the vantage point for the second run makes one wonder whether he is running the same spot, in the same conditions.



I ran a spillway once, kept the boat straight, and drove it through the backwash. The guy behind me, in a Blue Hole OCA, was turned, spilled, and recirculated for quite a while. We at least had an excuse for our attempt, because signs along the bankside portage route said NOT to trespass.



If I could, I would get youtube to pull this video. It does not send the message we want sent… Don’t run stuff like this.

Screaming little faces…


http://video.google.com/videoplay?docid=-6846124409391034920

0
http://www.youtube.com/watch?v=IPaCXSwjLA4

That was good! How did you get a
volunteer?

a tribute
To go over the first time may have been simple ignorance. To go over the second time was sheer stupidity. The clip is a tribute to the durability and stupidity of youth.

His "inspiration"
http://www.youtube.com/watch?v=cx0JyzJNqQk&feature=related

The guy in the video posted it on
boatertalk, and is he getting hammered ! Everyone told him he should not have run a low head dam. He called it a 2 foot “waterfall” and said kayakers run 15 foot waterfalls. He was told it was not the height of the drop, it was what happened at the bottom.



The video really sets a very bad example.

The sad part
is that despite all the warning posts and explanations of the danger he did not get it and wants to go back wearing a helmet and paddling harder at the bottom.

Yeah, he seems not to understand the
part about the backwash. I told him that if the water had been a little higher, the backwash might be strong enough that neither of his attempts would have ended well.

Let’s hope he doesn’t breed.

Just a young kid.
Let’s hope some of the stuff sinks in before he goes out again, I would have hated to be parent or friend filming and realize he was going down for good. I don’t know about the rest of you but I was invincible when I was 15, I was into downhill racing and gelande jumping and have the broken bones to show for it. For most males judgement comes slowly with experience.

90% + survival
People will always run these things, because there is a big shance of survival, like 90% or 95% or maybe 99%. They see people do it, or do it themselves, then warning signs be damned. The best you can do is warn, and take your 1% casualties - or don’t build them in the first place. How could you design them where they aren’t traps? By having the bottom on a 45-degree slope? Couldn’t you have the same problem at the end of the 45-degeree segment? Alos, it seems like you might have a problem where a given design might be safe at one water level but still a trap at different water levels.


is this safe?
Well, maybe not exactly safe, but fairly free of backwash entrapment danger?



Look at the end of this run - you only see it for a second each time someone comes down, but pause it around 0:54 and you’ll get a good look. There might not be much backwash here, depending upon how the bottom is shaped under those waves. Or do the waves indicate backwash?



http://www.youtube.com/watch?v=n_EtObcbOBI

What do you think will happen with a
higher flow? The same inexperienced people running it, but with a stronger backwash…

don’t know
I don’t know, I guess it would be more dangerous as the rapids at the end would be bigger, but as long as the level at the bottom isn’t over the wall shown, I don’t think it would change the hydrolics. As long as the chute keeps flushing out, and assuming the area below the chute is a big pool (which the picture doesn’t show), then you would seem to be safe from backwash-entrapment.

How do you know?

– Last Updated: May-24-09 10:50 PM EST –

Do you have statistics to back up your assertions? I think you are looking at the wrong characteristics of the situation. The major problem with low head dams is that they are river wide and uniform. The amount of drop is irrelevant. A natural waterfall is irregular. You can often move to one side or another and take advantage of the irregularity and escape. The video shows a low head dam that is not river wide and is not uniform at the ends. But most paddlers would not recognize that. And they could easily conclude that a low head dam that is dangerously different looks just like the one in the video. The message is a killer message to those who do not know better.

I do not have the impression that there
are ANY rapids prior to or following the low head dam. An increase in flow will almost certainly strengthen the backwash or hydraulic, and will make it harder for a paddler to blast through the backwash, or to swim out of the backwash if the boat is captured.



I can’t say how dangerous this particular low head dam is, but as a class, such dams are amongst the most deadly features on rivers. That is why it concerns me when someone passes around a video of running a low head dam. It can only lead to imitators, some of whom may come to grief.

wrong dam
I was referring to the dam in the video I posted, not the original one, since your comment was in reply to my “is this safe” post, not my “90%” post.



As for the original post dam, yes, I agree, if it was much stronger that guy would not have gotten out on his first trip. But the water also have been flowing faster and deeper over the lip, giving him more chance to boof it. So, it would still seem to be in the general 90%+ survival class.



By the way, in case anybody missed the point, I bring up the 90% survival thing only to explain why people do it, not to justify them doing it. If you do JUST ONE 90% survival stunt every summer from your 16th birthday, odds are you’ll be dead by 21.

99% survival rate isn’t good…
When you think about how many people may go down a river in a summer in canoes, innertubes, rec-kayaks.



Say you have three scout troops of each weekend … a ninety nine percent survival rate would mean killing about 52 young kids a year.



I used to work near a lowhead dam on Clear Creek in suburban Denver, near I-25 and US-36. Several people drowned in the hole there in the 7 years I worked at the company. All of those deaths were needless and stupid. There were warning markers above the feature but people paid them no heed because it looked so trivial and safe and the water did not look like whitewater in that area at all.