imaudigger, post: 396345, member: 7286 wrote: At 30 to 40 ft deep, you will have a difficult time determining where the top of the pipe is.
Is it out of the question for the maintenance crew to enter the manhole with specialized equipment?
I'm thinking the worker would have to have a harness on and be lowered via. a cable/winch. Obviously using fresh air line.Not familiar with doing something like this, but I'm sure it could be done.
I was working with a town sewer Dept. They had the guy tied off in a manhole where we had place a monitor for flow. Only problem the manhole had a pumpline coming in about half way up. You could hear the extra flow coming and had to crank him up a few times.
Thank you all for the replies. I haven't been logged in for a bit. I like many of the ideas but I'm still on the fence as about it as well. I think going at night will help out tremendously.
Hover this over it. http://www.riegl.com/products/unmanned-scanning/newbathycopter/
not my real name, post: 396348, member: 8199 wrote: First of all, I would refuse to do this. Secondly, it is hydraulics, not hydrology.
The time to get record information on how the pipe was constructed is when
it is being constructed and not afterward. Once there is back fill over the pipe
that is all I see.Then the assumption that people will want you to make after you obtain the invert
elevations is to calculate the slope of the pipe between the manholes.Without seeing the pipe there is no guarantee that it was laid straight or at a constant
slope. I would not assume any liability without these assurances.
Yeah, I believe the municipality has lost the as built info, etc. Definetly going to hit on all those "assumptions" in the contract and have some careful language.
We haven't done it in a few years, but we used to do river cross sections in some pretty extreme flows from a jetboat. We bought several 10' lengths of 1" steel electrical conduit with threaded ends and used as many as were necessary for each site. In our scenario we had a prism mounted on the top section of the rods and shot it from shore at each point. For your situation I would probably duct tape a level rod to the conduit at some fixed distance from the bottom and read that.
