Repairing a pond dam.

[aarolar]

I have a large pond on the back of my property that has been busted since I bought the place. It busted at some point due to beavers blocking the run around and now I have a 15' wide by 15' deep hole missing in the dam. What is the proper way to repair this what equipment would it involve. Could I make any progress with my MX4800 if I had dirt brought in considering I have unlimited time avaliable?

 

[TripleR]

Pretty much as mentioned, but be sure to install a proper overflow pipe and depending on the size, find a way to keep the water out until finished. And based on our experience you are sure going to need unlimited time to properly fill and pack it. We had to ponds "blow out" that were professionally built when they got filled too son after the build due to excessive rain.

Be prepared for it to take much more dirt than you think.

 

[aarolar]

What options do I have for keeping the water out while I repair it? This could be my biggest roadblock due to time and money restrictions.

 

[bindian]

I'd clean out the busted section to get down to clay with an excavator. The years you are talking about put a lot of sediment over the opening. Leaving it could give you a weak "layer" separating the original core trench clay from your "repair"clay.
I'd also notch into both sides of the opening to give it a tongue and groove shape. Kinda like a splice overlap when looking down at the dam.

Pack it down as Eddie mentioned above. I know, as I have had the same pond fill before the dam was finished and then again during remodeling. Eddie's method for packing is what I used. So far the dam is holding unfinished, with a foot of water going over the spillway and four spots over the dam, last Saturday!

Get a Honda water pump to keep the water down. I bought a Honda 2 inch pump in 2012 (when I built the pond) and now have over 225 hours on it with no problems. Be sure the pump and engine both are made by Honda.
hugs, Brandi

 

[TripleR]

What options do I have for keeping the water out while I repair it? This could be my biggest roadblock due to time and money restrictions.

We used a gas powered transfer pump and left it in place covered up when not in use. On one, we borrowed a diesel irrigation pump from a farmer friend.

Like Brandi, we prefer an excavator, but it can be done with a tractor, some method of compaction is essential.

 

[Xfaxman]

What options do I have for keeping the water out while I repair it? This could be my biggest roadblock due to time and money restrictions.

Setup a temporary siphon:

 

[D2Cat]

I would get some bentonite to mix in with the fill material. You can get in bags at many farm/feed stores and some locations you can buy it bulk.

If you don't have good tight clay you could be facing a leaking pond after all the work is done! The bentonite will help that problem.

 

[lexluther]

Seems like a good opportunity to add an outlet that would allow sediment buildup to be released from out the bottom.

 

[roadhunter]

I've done a few dam/pond rehabs from small dams to large dams on state/federal land. A tractor is a poor choice for this kind of work IMO unless the soil is very solid and dry. All you will do is get stuck unless you dewater the area for an extended period of time before you start work. A tracked excavator is the proper tool for the job. Working with sloppy silt is no fun. It's easier to build a new pond and dam than to repair an old one.

I'd go with the siphon pipe method if possible. Running a gas powered pump gets old and can be an issue if there is a breakdown. Depending on your flow a smaller electric pump might work. I've used the little electric multiquip pumps on jobs with success and it takes time for most soil to dry out enough to work with if you are dredging.

Also this is the opportunity to choose a overflow for the pond which is a big decision IMO. Typically there are what is called stop logs used to adjust the level in smaller ponds but some use PVC pipe or other methods. Might want to use some rip rap where that overflow lets out to prevent erosion as well.

 

[Redneck in training]

I would get some bentonite to mix in with the fill material. You can get in bags at many farm/feed stores and some locations you can buy it bulk.

If you don't have good tight clay you could be facing a leaking pond after all the work is done! The bentonite will help that problem.

If you don't have good clay then bentonite might seal whatever material you use. There are several types of bentonite. The type you need is sodium bentonite because it swells when wet plugging all the crevices in permeable soil. If I remember it right I paid about $5500 for 16 tons delivered from WY to IA about 8 years ago.