Lake drain pipe sealing 1

[moosetracks555]

My dad has a 18 acre lake that had a drain pipe that he didn't know about until it began to leak. He found the drain end of the pipe and it is now open and draining and after lots of scuba diving with terrible visibility he finally found where it is in the lake buried under a mound of rocks near the center of the lake 22 feet underwater.

He is having a hard time figuring out how to fix it. The pipe is old and rusty and someone told him that capping the outlet would eventually cause a leak somewhere else. So for right now its still draining. Its about 2" in diameter. They sent a camera up the pipe, but from all the silt they could not see the walls of the pipe to inspect it.

One company said they could pump a grout mixture from the outlet up through the pipe and that would seal it up, but other companies have said that it may not work and not completely fill the pipe because of its deteriorated condition and create a leak in a detrimental location. Their plan was to pump 3 times the volume of pipe in grout to make sure and make it all the way to the lake.

Another company said they would bring in equipment to move the rocks and then pump the mixture from inside the lake However they are out of state and they wanted a small fortune to do it.

I would think pumping from the drain end would work because even if the pipe is damaged elsewhere the holes around the pipe would eventually be filled with grout continue to make its way to the end of the pipe inside the lake.

Does anyone have any advice on this?

 

[cvg]

you need to observe the grout coming all the way through into the lake. you need to monitor the pressure and volume of grout to make sure you pump enough and that you dont have a blow out inside the dam. you do not want to have a pressurized pipe running through the dam embankment, that is a recipe for disaster.

given the size of the lake, you may well have a jurisdictional dam. assuming the dam is about 30 feet high and with 22 feet of water in the middle of the lake, you could easily have 200 acre-feet of water stored. you do not want the dam to breach because of a leaking pipe at the base of the dam. suggest you ask your state dam safety engineer for some help with this.

 

[r13]

I wonder to what purpose the pipe services? 2" steel pipe, with/without control valve?

 

[cvg]

2 inch is hardly large enough to drain such a large lake, typically these type of small pipes are for water supply/irrigation

control valve is often on the downstream end which is much cheaper than putting on the upstream (lake) side
unfortunately, this is a risky design and not recommended under current dam safety guidelines

 

[r13]

What I am trying to point out is, it is a weird design, but it might serve a special function, which should be found out. The best scenario is it could be a convenience of drain during construction, but forgot to cap off.

 

[cvg]

installing pipes through dam embankments is frowned upon, especially for convenience. capping them off is not an accepted practice. they create a potential failure mode which is hard to mitigate, especially if they are constantly under pressure. but they do provide steady work for us dam safety engineers

 

[r13]

Not to claim I know dam design, but I doubt the 2" pipe is for unknown function. For purpose of irrigation, wouldn't be there a intake, or gate structure? The problem now is that the pipe could have rusted through, that allowed the entering of fines, so the water is steady streaming, leaking out (piping?), instead of pressurized water jet, as it would be under 22' head.

Engage a dam safety engineer/expert should be in the highest order sooner than later.

 

[moosetracks555]

Thanks for all your input.

We are not sure of the purpose of the line. He didn't dig it up to find out where it went or what was on the end. It was found when he noticed a soft spot and water coming up through the ground. After digging it up the pipe was left open on the end and had been flowing unrestricted. It has not drained the lake and like others have said its not near big enough to do this.

What type of companies have equipment to pump grout monitoring pressure and volume? Well drillers, or is there something else that I can search for in my area that might lead me to someone that can do this type of work?

 

[cvg]

probably not a driller, a specialty contractor. the equipment is not that sophisticated. volume monitoring simply means counting the number of bags of cement and gallons of water added

 

[LittleInch]

So is this a private dam / artificial lake?

Any sort of a cross section of what it looks like?

How far is it from the current soft bit / leak to the edge of the dam section?

Anyone who does concrete pumping should be able to do grout pumping or knows a man who can.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[moosetracks555]

Thanks again!

@CVG
We will try contracting some concrete pumpers and see what we come up with. Were those pictures you found on google, or personal photos?

@LittleInch
Yes its a private damn. The current end of the pipe is about 30 feet from the base of the damn. The pipe is estimated to be about 300 feet long and extends 100 feet into the lake.

 

[r13]

IMO, you shouldn't rush into action before consulting a dam expert/engineer. You might wounded up grouting the dam instead of the pipe unless the physical condition of the pipe is made known. Also, is there any source of water inflow to the lake, such as stream or creek? And, is there any feature for overflow? I don't think you have answers, that's where the expert to fill in.

 

[cvg]

my personal photos

 

[r13]

I suggest to install a control valve at the down stream outlet, and you may conduct a pressure test after that to confirm the intactness of the pipe. Grout it only at the instruction of an expert. Good luck.

 

[GeoEnvGuy]

If you go to a cementing contractor ask them if they have heard of a Van Ruth Cementing & Wedging Plug. That will probably be required so that you can grout the pipe.