My farm is in a river bottom flood plain. According to the records my potential lake site would only would have flooded 4 times since 1971.
1)My concern would be pressure on both sides of the dam?
2)When water gets high the discharge wouldn’t work so I’d need to have a rip rap or concrete spillway
3)Other fish coming in through the creek that feeds the lake and then flood waters.
4)My fishing leaving in a potential flood

I’ve had two lake builders tell me it’s doable but have not go prices yet.

One lake builder was worried about the river.
1 option is 12 acres
2 options is 18 acres
Below is my thoughts. The small blue area is 1 acre pond I built a few years back.


Thank you for reading

Are you in the U.S.?

Building a sizeable dam in a floodplain will almost certainly require multiple layers of government approval. That will be quite expensive to pursue.

A groundwater pond (no dam) in a floodplain would be much more likely to be approved (depending upon your state). If your excavated material was moved OUT of the floodplain then your project would not be worsening the flood height. However, your pond would definitely have the problems of fish going in and out during floods.

Water pressure on both sides of the dam is not a problem. A normal dam has water pushing on one side and air pushing on the other side. This is obviously unbalanced, so the dam has to be built strong enough so the water side does not push downstream.

Water on both sides would be more stable. However, rapidly moving floodwaters are highly erosive. Rising flood waters moving parallel to the long axis of your dam could erode the dam and cause catastrophic failure.

P.S. The link to your pond site did not come through in your post.

I think you need to post a lot more info to get more definitive help from the Pond Boss experts.

Good luck on your project!

Yes sir I’m in The US.
Trying to get my pictures to work. Thank you for the response

SSW of Birmingham. Alabama

Hey man! I don't know what to say, and I'm not a specialist. But if it has the potential for flooding, I do not recommend building a pond. It is best to keep your farm in a safe place, away from flooding or other damage. Maybe you've never been through a flood, but that isn't very pleasant. I have only been through such situations once in my life, and since then, I have avoided houses near the ocean, the sea, lakes, etc. The good part was that we quickly found a company that helped us with the water flood damage, and we got over it quickly, but anyway, I don't want anyone to go through such situations. So I do not recommend you to build a pond near the farm for your safety and in addition to all the construction process is very difficult, requires a lot of documentation and is not worth it in my opinion.

As I recall Bob Lusk had an article in Pond Boss Magazine about his experience managing a newly built pond in a flood plain. It was a really good article, but I don't know what issue it was in. Seems like it was two or three years ago. There were definitely some travails.