I have a 14 acre lake that is about 20 years old. Recently, the water level control drain pipe developed a substantial hole on the underneath side about 3 feet under normal level (looks like rust and corrosion). The pipe is 24" corrugated galvanized steel and is 100' long running under damn. There is no stackpipe.

I attempted to temporarily fix the leak by strapping a piece of corrugated steel to bottom of pipe. It worked great for about 10 days until water pressure caused the pipe to bend upward to the point that the pipe is no longer under water.
This has raised the normal level about a foot and if it rains, the lake drains over emergency spillway.

- Are there ways to fix this without digging up and replacing entire drain pipe?
- What is reason not to use emergency spillway as permanent drain system?
- What can be done to reduce fish kill if I have to drain lake down approx 6 feet?

Welcome to the forum!

1) Not that I know of.
2) If the emergency spillway is earth, the water will slowly erode the soil at first, then faster, and you have the potential of the whole dam breaching if a large enough rain event happens for a long enough duration.
3) How deep is the pond ? The fish might very well survive the drawdown to fix the dam without any significant fish kill.

Can he plug the existing drainpipe (hydraulic cement) and then install a siphon system instead? This may prevent needing to drain down the pond to the level the pipe was installed at.

Just a thought, I could be really off.

No, you are correct, I didn't think of that. It'd take a bunch of hydraulic cement even IF you could plug it tight enough so the cement wouldn't run all along the 100' length..........

Assuming the corrosion is limited to just the 6 - 8 feet of pipe that lays in the lake, could I drain the lake down to expose "good" pipe, cut it off, install a 20" PVC into end as far as I can ram it (but at least 3 feet), pump calk into space between pvc and corrugated, attach pvc to new stack pipe?

I know this sounds complicated, but it would save me a TON of $$$.

Since steel rusts at about the same rate if O2 and water is present, that might buy you some time. Whether it's 6 mos-a year or 5 years I have no idea. Who's to say the pipe inside the dam isn't rusted thru too?

Get a plumber who has one of those cameras on a snake to inspect it first.

"Camera on a snake" - great idea! I'll start looking for a plumber w/ a snake.

Does anyone know of a website that provides design ideas for stackpipe? I understand there are issues w/ vortex if not designed properly. Also would be interested in options for grate over top so as to prevent people from getting sucked in and also to keep large debris from entering.

Maybe these guys?

http://ponddampiping.com/accessories1.html

Its been almost 3 years since I started this thread and the damn dam still isn't fixed. The pipe finally rusted through and broke off right where the pipe goes underground into the damn. It is 24" corrugated 110 feet long. The drain pipe broke off about 2.5 feet lower than "normal water depth. With the loke lower than normal, I was able to dig a new spillway adjacent to emergency spillway. In the next couple weeks I will pour cement in new spillway. Then I will plug old pipe and start using new spillway.

My question is what is best way to plug the old pipe? So far, best idea I have heard is to ram a makeshift plug at least 6 feet into pipe then fill with hydraulic cement. Any other ideas? I'd like to plug it from the bottom, but that is 110 feet of cement = 12.8 cubic yards!!!

I'd dig the pipe out 20' back on the pond side, pack the dug out area with clay and call it good.

Filling the pipe allows the metal outside of the concrete to rust away, and how do you know water won't seep thru that area?

As esshup said, dig out the old well into the core of the dam, then re-compact the space. It is a perfect time to install a quality bottom draw siphon system too!

It isn't a fun job, nor cheap, but sure cheaper than 12 yards of concrete that is far from a "sure fix" and would probably still allow leakage.

What part of MO are you in? I am in the St Louis burbs.

I am in the Robertsville/Catawissa area, about 12 miles from Pacific. I grew up in STL. Where are you located?

I'm sure esshup is correct and I should dig up old pipe, but I just don't have the $. The job has been bid 3 times and all 3 came in over $20k. At $100/yard, I can buy lots of cement. Reason for high bids = The pipe goes down at such an aggressive angle that 20 feet of pipe would be an enormous amount of earth and deep hole. As dirt is removed, it will have to be stacked on back side of damn to build platform for backhoe. Also, not only will lake have to be drained, a coffer damn will need to be constructed so as not to breach the hole during construction.

While that's the bad news, I think it may also be the good news. If I can plug the pipe, it will be entombed in lots of packed earth.

I am no pond expert as many know here. But I would think about 3 plugs in the 110' of pipe. One in the bottom, one in or near the middle and one in the top. it works in the oil patch when plugging pipe.

Tracy

Call Mike Otto (940)665-2258.
He's repaired many corrugated pipes, some of which he installed 25-30 years ago.
There are several approaches he takes.
One is to pump the rotten pipe full of concrete and improve the emergency spillway and leave at that.
Another is to run pvc pipe into the corrugated pipe, pump concrete around it and the pvc pipe becomes the new primary spillway.
Another is to dig up and replace the rotten pipe.
Another is to dig into the emergency spillway, put a pipe there, along the entire length of the emergency spillway, add anti-seep collars, seal around it and bury it...and you have both the overflow pipe and emergency spillway.
Another is to build a siphon pipe, install it at water level through the dam and concrete the rotten pipe.
What you CAN'T do is leave it as it is.
I'd call Otto...he's "been there, done that".

Another vote to call Otto.

I cannot thank you guys enough. I will call Otto.

I'm no expert, but if the pipe is plugged and there is no leakage around the outside, it is unlikely for the plugged area to rust. Very little O2 available to rust it.

Thinks makes me thankful I have been able to get away with just an overflow, and my pond is relatively small. If every I struck the lotto and fell into a larger pond, it would be a pvc siphon drain.

I am glad that I went with plastic pipe in my pond and not steel!

I live in Maryland Heights, grew up in the KC area and Boonville, Mo.

Please keep us updated, and take/post pictures of the repair you go with! Lots of people can benefit from proper repairs!

Hi folks,

I am also in the club of pond owners with a failing corrugated metal drain serving as primary spillway. I am quite interested in replacing the failing system with a pond siphon, and I think the pond would be well suited to it in terms of placing the through the dam pipe at the desire water level vs. the elevation of the emergency spillway. However, I am wondering about peoples experience or satisfaction with siphon systems in regard to maintaining a relatively constant water level. The existing system has a 24" vertical riser which drops 4' and then drains out through a 15" inch tube, so the water level remains pretty constant unless you get a pretty good rain and even then it takes it back to normal pool pretty quick. With a siphon, which I anticipate would be 12" pipe aren't I going to have quite a bit of rise before it begins moving very much water? So I am going to be subject to rises of several more inches than we typically experience with the standpipe system, right? I probably wouldn't care much about 4-6 inches regularly, but 9-12 inches all the time might be less than desireable in my view. Anyone have any thoughts?

Also, I really don't want to go the route of multiple smaller siphon tubes due to the inceasing expense.

Thanks,

Matt

I have an old metal standpipe in my pond. We moved here with the pond already existing. I am not certain about when the pond was built, but I assume in the 60's - 70's. My husband went out to unclog the standpipe and it broke off. We aren't sure how far down but since treating the algae bloom, we are losing water rapidly. It sounds like a bathtub filling up and water is gushing out the other side of the overflow pipe. Is there any way to decommission this standpipe without draining the entire pond? We tried to put a seal over the pipe, and worked but then we began finding seepage and leaking around the pipe. In fear of losing the entire dam, we removed the seal and the pond is now draining as mentioned above. It is well stocked with large bass and brim and grass carp and maybe others. We don't want to lose all the fish. Any suggestions? Also, once the standpipe is decommissioned, what type of overflow would be recommended? We do have an emergency spillway (just a sloped area to the side of the dam - no pipe or plastic) in addition to the standpipe.

Drain Pipe Needs Repair that it's better get the line to butt up as near each different as conceivable to stay away from any means inside - this being something structure control majors are entirely search on obviously.

Jennifer, Lots of possible or potential fixes but I doubt any would work.

Ha!!! Dave, this one is a fooler. Dates are so close it took a while before I noticed it was a post from a whole year ago. I wonder what ever happened for these folks. Both ( Jennifer and townpops ) never had any responses.