I will try to tell my tale. Bought a property in Lawrence Co, Indiana with some acreage for a retirement place. The house needed work and it had no pond. Both of those can be fixed. That area gets a good amount of rain/snow and there is a lovely wooded ravine begging for a dam. I asked around and found the consensus among pond owners that one gent was the master dam-builder in the area. We spoke and looked at the site. This is a very rural area and he'd played in that ravine as a kid as relatives are next door.. well, I'm practically in the clan now. He sounded much more knowledgeable than I, though as a mechanical engineer, I have some of the fundamentals. He described significant water flow events and the need to have a solid core, lots of freeboard, good overflow & spillway capability, a valved drain line under the dam with collars, and such. It sounded like he was on top of the game, so we shook hands.
I spent the entire summer logging that ravine, me and my chainsaw. They wanted all the trees down, above the waterline and below the dam. I dropped trees, cut them up and half-filled my barn to the roof. It will be about 1 acre and 14-15' deep by the dam.
Clearing out the draw
The last of Sept, he brought in his ace dozer man (70+ yrs old and lots of dams under his belt) and he ran a track hoe (excavator). They spent 2 weeks building the dam. They took out every stump and scraped down to solid rock. They declared the soapstone to be a good solid base that won't leak.
The sides are fairly steep, some is bare rock, some soil. They took soil from the ravine, and then had to go out to the sides of the dam to get more.
They put the 2" PVC drain line in when they started, along with collars on either side of the core. I couldn't say how thick the layers were they built the core with- and it appeared they compacted it with the dozer. The drain was fed by a 7' vertical section of pipe that had been drilled with small holes both inside a rock-filled barrel and to the top above the barrel.
You can see the drain arrangement standing in the bottom of the pond when the dam was almost done. And that is a lovely cherry tree I dropped and took out when they told me the roots would be under water.
Note there is no overflow pipe at this point. They said they would put that in with the track hoe, but then they blew a hydraulic cylinder on it. They said they would put the pipe in with the dozer. I wasn't there, so I don't know how they did it.
This is the dry side of the dam at full height, before the overflow went in.
Next time I saw it, it had rained 4" that weekend. There was 7'+ of water. That was scarey.
One weekend's rain in the pond.
I had some good email chats with Esshup and decided to stock fatheads and gold shiners and give them a year to do the fishy thing. I will put in bluegill, redears and LMB in a year.
I had fun building habitat up in what would be the shallows. I did PVC structures, slate nooks, pallets with rocks piled on top, etc.
So it filled gradually through to December. Before Christmas, it lacked about 3 1/2 feet to the overflow. It was going to snow and go cold. It froze over completely in one day- but then it got down to -14F that night.
Nice snow, the day before it froze over.
After Christmas, I got a call from a neighbor. It had rained hard again. "The overflow pipe is down in your field below the dam and there's a huge hole." Needless to say, I took a quick trip down to check on it. What I saw about made me cry.
50' long (12" dia) overflow pipe is 30' downstream
My pond man saw that two pallets were lodged in the hole in the dam. They'd gotten washed out from the top of the pond. (Should have attached the rocks or blocks so they wouldn't float) He declared the pallets blocked the overflow pipe, the water swirled around the entrance, and caused the pipe to come out.
Still water, but big hole in dam
Now as I see it, even if the pallets got to the pipe before it failed, it shouldn't make a pipe wash out. The water never got anywhere near the emergency spillway (far side of the dam in view above), you could tell from the leaves how far it got. It looks like the overflow pipe washed out pretty much as soon as water got flowing through it. There was a large water outflow, the newly sprouted rye grass, oats, and winter wheat were flattened but still rooted along most of the back side of the dam. There is a lot of dam soil downstream in the drainage and a large mound where it dumps into the creek.
There are no collars on the overflow. I theorize that they did not get any decent compaction around the pipe when they dug a channel for it and back-filled with the dozer.
So we need to have a serious discussion. I'm not the expert, but I really believe he's trying to shift blame for bad work by saying it's the pallets' fault.
What to do next? Very good question. Obviously, I welcome input from you all. I fear I do not respect his input quite as much. I know I need a good bit more soil to rebuild and I suspect we'll need to draw the water down a ways so they can get equipment in there. I am thinking I should offer to pay for several dump trucks of good clean (not rocky) clay soil. I suspect we should create some kind of collars for that pipe to prevent seepage along the outside. They didn't do anything on the entrance of the pipe. No concrete facing along the dam, they just broke the pipe along the angle of the dam so it was flush. With clean soil, can you get decent compaction with the bucket of a track hoe? I'm willing to fund and run a manual compactor if that's best. I kinda think he needs to fund their time rebuilding, but he may not agree.
Isn't that an interesting way to get into the world of pond management?
