Hello all,
Excited to be a forum member. I have a pond that is just over an acre and over the years it has filled in with silt due to field runoff (will most likely be an ongoing issue). The pond used to be about 20-25 feet deep (according to my dad) and has now filled in to about 5 feet at its deepest. Watermeal and Duckweed have taken over and I usually have a fish die off every summer. My question is, do you think I would be better off draining the pond by cutting the dam out and then going in with a bulldozer, or would there be any benefit to using an excavator to periodically dig out what can be reached?

The quality of the fish is very low due to the yearly die-off and some green sunfish have taken over. It seems to me that draining it and starting over would be the best bet, but I wanted to get some thoughts. If I do choose the draining route, how long do you think it'll take the dirt to dry out enough to get a bulldozer in there to push the dirt out and over the dam? There would be a creek running through the middle and a couple small springs that would continue to flow, but I would think those wouldn't have a major effect on the drying time but I'm not sure.

I was wanting to create shelves at different depths and also add in some fish habitat, so draining and doing that without water seems easier to me. Thoughts?

Thank you in advance,
Matt

Do you have the real estate available to increase the height of the dam and increase depth that way? Sometimes that is the best option.

I'd cut and drain. That way you remove the sediment that has a BUNCH of nutrients in it which are causing problems like the duckweed. Just plan on it being a year project - it will take time to let the muck drain and dry so the dozer can push it.

I think i could raise the dam a foot or two, but not sure it'd be enough to solve my issues. When rebuilding the dam after cutting it out i could raise it up then and i think it'd be an additional benefit. Thanks for your response!

Not a pro here, but I would dig a temporary catch-basin, hay bails, small dam, etc. behind the dam to catch the silt coming out, cut the dam as a narrow channel to begin with, and take advantage of the stream (depending on the flow) to erode a lot of the material out for you. Maybe help it along with a trash pump to stir it up along the edges to wash it out. Then you can get an idea of actual depth to know how much material you actually need to be rid of.

Once you have a grip on it, let it drain, widen the hole to the size of the dozer when/if it comes time.

The concern is if it was really 25ft deep once, there will be a hell of a lot of pudding to deal with. I doubt if it is that deep that the goop will dry out before we kick the bucket, but the goal is to get enough water out of the silt/muck that it can be dealt with.

As people are alluding to, it is complex and messy work to drain with a steep price. Building up the dam is likely cheaper and results in a usable pond until it too fills with silt.

If you go the draining route, once cleaned, it may make sense to install a bottom-feeding siphon system that will at least excavate the areas where the pipe sits.

But, if just raising the dam, you will still have all the excess nutrients in the goop in the bottom of the pond to deal with....... What's that going to do to the pond over the next 20-30 years and what will it cost over that time to keep the excess weeds/algae at bay?

We just finished draining our lake to scoop out the muck. It's close to three acres and the guy who did it for us first dug out a hole in the dam in stages with a backhoe and then came back this year and dug it out big enough to get his loader and dozer through the hole.

It was a year before he could get his equipment back down in the deepest part. He came out a few times over that year during dryer periods and would work on the areas adjacent to the deepest muck which seemed to help that area dry out more. He said he would have preferred to let it sit for two years but this past week he was able to run his equipment through the deepest part without issue and get a lot of it out.

He originally wanted to open the dam and then push all the sloppy muck out the hole while it could flow easier but our dam is close to the property line and our neighbor was not going to agree to that. We had to drain the lake in stages to be careful not to make too big of a flow to where it damaged our neighbor's property or released muck onto it. I contacted the DNR prior to getting the work started and they said it would be a legal issue should any muck laden water make it to a public stream about a half mile away so that was a concern as well.

If it went from 25' deep to 5' deep you have an enormous amount of muck to deal with, that being said, imo, raising the dam height will be a like a small and somewhat ineffective bandage for a bigger problem and even if it somewhat worked it wont be a beautiful useful body of water, cutting draining and cleaning it out will result in a much better product, although a little expensive, probably comparable to the cost of building one from scratch, but you would have basically a brand new pond. and you might think about puttin a silt catching pond right above it to avoid as much muck in the new pond, and could also be used as a forage pond. Good Luck!

Agree - time to drain and get the muck out. Be ready to deal with DW seeds in any muck remaining.