Stream Profiles in Rapids or near Falls

Or do it yourself with THESE as pontoons. A rope to each bank...slowly let it float downstream.

DDSM:beer:

UM, I believe he is talking about this kind of water.
White water rafting.

Thats more like it! Not quite as rough but more than I can put a boat or a person into.

Tom

Just off the top of my head the only way I can see being able to do this without getting in the water (and be somewhat economically feasible) is to make a rope bridge. Send someone out on the bridge with a safety harness and the prism rod/level rod secured somehow and profile it.

Cy

I've seen machines rigged up with a cable that spans the river with pulleys, weights, sounders, etc., the idea being you can move the cable back and forth across the water to get your position, then lower the sounder to get depths, but I'm not even sure that would work in very heavy rapids. Perhaps they can increase the weight on the sounder to make it work.

I found some info on it. This one says it can handle flows up to 9.2 feet per second, but I'm not sure how that relates to rapids ...

http://stream.fs.fed.us/news/streamnt/apr00/apr00_1.htm

Link doesn't work. At least not entirely.

I've done a number of small bridge replacement projects back in MI. It didn't really involve profiles of the water course, but cross sections. Both sides of the structure, 50'to 100' upstream and down stream, then another cross section approx 1000' up & down stream. Generally they were 20' to 80' wide.

Several times due to rapid water flow I donned my wetsuit, life vest and sturdy rope. Tied it to a tree on one bank, made it across to the other bank. Got it taunt, and then clipped myself up while I went back and took the necessary shots.

It sounds like a time to be creative. I'd think you could create a profile from many cross sections. If the flow is that heavy, I'd be the first to ask why they want to know and how accurate does it need to be? You could always use a big, really big, heavy chain with a big load attached and figure out a way to drop it down at whatever interval you need. All the while using a safety rope from bank to bank.

Or an experienced kayaker with all that GPS gizmo stuff attached.

Sounds fun. Need an extra helper?

Is there a different season with much lower flow?

It's not dam controlled somewhere upstream, is it?

Dam

These lower a velocity measurement device into the stream with a streamlined weight that minimises the drag on it. I think it might not be able to cope with the velocities and turbulence you have though. It would be an expensive experiment!

My Dad used to do it many many years ago. I think they may have more accurate methods now.

Yes, would be safest to wait for a drought or at least the driest time of year.

Yes, you are right. I don't know what happened there, the search still shows up in Google and Google Images, but the page is now either down or removed. I doubt that page saw much action, so maybe the 15 hits it got from beerlegs was overwhelming and crashed the site. 😛

Shhh don't let anyone know but....

(okay you did NOT hear this from me... okay?)

There is a little known technology called UAV's. You may have heard of it? Well, some have said that you could even get topographic data from one of these things! Sounds very safe to me. Especially for something like this hmmm?

Just a thought..... 😉

Shhh don't let anyone know but....

Didn't know they could fly underwater.

Shhh don't let anyone know but....

> Didn't know they could fly underwater.

http://www.airbornehydro.com/

What sort of depth are you talking about? Is this a case where you can double tie off upstream and "walk" it out?

I volunteer Thadd (spledeus) and Bob F. for the task, I know they are up for it!

Dtp

Shhh don't let anyone know but....

Couldn't have said it better ?.

Airborne Hydrography

Are there any firms using this technology in the USA?

DDSM:beer: