I have a pond that breached the dam before I owned the property. Apparently, the last dam lasted for quite a while, about 20 to 30 years. It was simply compacted dirt with a culvert stuck through it at about the 4’ high. It appears water started leaking around the entryway to the culvert and eventually washed out the dam over a couple of years.

I need to repair the dam so I can collect water in the pond, attract waterfowl, and use it elsewhere by pumping it for irrigation or to fill other small isolated ponds.

The dimensions of the breached area are:

23 feet long channel

12 feet wide at top of channel

5 feet wide at bottom of channel

9-1/2 feet deep

If I put a spillway wall in it would be about 20 feet wide at the front, curved towards the oncoming water pressure. It would be a single wall of CMU w/reinforced concrete poured from top to bottom in the voids. It would also have 3 support ribs of CMU wall supporting it w/reinforced concrete poured from the top down as well.

The rear spillway would be about 10 feet wide, curved away from oncoming water, supported behind it with 3 rows of CMU, w/reinforced concrete poured from the top-down as well.

My sketch of the fix is larger than 2mb so I can't post it. Email me if you are interested in helping and I'll show you the plan as well as a couple of photos of dam and pond.

Recorring it and packing it with good clay would probably be better than concrete..

Agreed. The new material should be knitted in with new soils. Concrete doesn't knit or mix very well.

Welcome to the forum ylekyote!

The concrete sounds expensive, and a bit extreme and as other's mentioned, it is not tied into the dam anywhere.

A breech can be safely repaired using a track hoe/loader and a very experienced operator that can stitch the new material into the old and compact thoroughly in small lifts.

You might want to consider installing a siphon drain system rather than just an overflow pipe if you are wanting to reclaim the pond for waterfowl. A siphon will give you much more pool level control.