Hi -

I'm new to the forum and this is my first post! So excited to have found this resource!

So I am the HOA president in a small neighborhood(40 homes) in Oklahoma that has a common area with several ponds. Our 2.6 acre upper pond has small 30' wide concrete spillway that runs into the lower 3 acre pond. This year I have noticed that it has begun to seep across most of the spillway and in one spot has a small but constant leak that we haven't noticed in the past.

If we wanted to repair this with the intent to prevent it from becoming worse in the future what is the best suggested method? Our pond maintenance people want to pump the upper pond down about 2 feet and run new concrete along the base of the vertical wall of the spillway. I'm concerned about doing this as we have a lot of shoreline vegetation that would likely die as the pond would take time to return to naturally refill. My idea was to sandbag in front of the spillway (depth is only about 1 foot and is a concrete base) and then pump out between the sandbag wall and the spillway. The pond guys others suggestion was just to gently dump bags of unmixed concrete at the base of the spillway. Seems like a lazy fix to me?

Pics:








Thank you in advance for any advice!

A couple of thoughts from a non expert in this area.

First, shoreline vegetation "generally' has deep enough roots to survive.

Second. In the pictures, it does appear that the leak is at the area where your "blocks" sit on the actual dam. If that is true, I don't think you would lose any more water than where you are now. And, at this time of year, you're probably not get rained out during the repair.

It looks to me like those "blocks" might have been bags of concrete that were put in place to raise the level of the pond years and years ago. What is the history of the pond and how long have they been in place?

I believe any fix will require the water to be drained, the concrete and blocks cleaned with a sandblaster or muratic acid to get a good clean surface for whatever you want to use to bond them together and create a waterproof seal.

Yes drain down so you can clean. They make a hydraulic cement for patching foundations, use that. Then cover with a rubber coating of some sort. If that does not work I would then take wall down and repour your wall. Good luck

I would not sandbag in front of the raised bag wall....if the wall lets go you will have all that sand spilling all over and it will make repair a pain

The bag method used isn't meant to be a water tight solution, it is simply slowing the flow of water and slightly holding back more water. Think of it as a weir with a distributed gap.

Hydro cement + a driveway type brush on sealer is your easiest bet. You'll have to clear all that sediment in front of the wall and power wash the face of the blocks. They make special bag crete for building those walls but in any case, none of them are meant as a permanent solution

https://www.quikrete.com/pdfs/projects/riprapprojectsanderosioncontrol.pdf

https://www.sakrete.com/products/rip-rap