Pond Boss Forums POND CONSTRUCTION Building a dam Washout around exit pipe on new pond... what to do

I did not use heat to bend the 1/4" all thread, but it may have been better to use heat. You can surely design a bar guard that will fit over the plate - its needs to be a larger anyway - more "surface area" to collect trash.

It does make sense to have a higher free board to enable full flow of the pipe. Since you are only adding additional free board to the top of the dam that will not always have water against it, its my opinion your tractor can do sufficient compaction. Perhaps have the dozer out to push dirt while you run the tractor with all the weight you can get on it.

Have NRCS tell you what elevation the emergency spillway should be too. ie they set my water level (8' pipe) at 99' from a benchmark, the emergency spillway is two feet higher at 101', and the dam top at 103 which was expected to settle to perhaps 102. On second thought just have them design a pond as if yours was not there yet, then see what it takes to make yours "right".

Do you have a plan on getting extending the discharge pipe down the back of the dam?

Since you stated on another site that you are going to drain the pond down, why don't you build a siphon system and let it do the work instead of a pump. Rick

I had bought a 6' stick of 1/4" all-thread (ebay I think), cut it into two pieces. I slowly bent them around the pipe trying not to kink it. No problem. After tightening the nuts down I sawed off the excess thread. Don't saw them off before getting it through the holes you drilled in the plate!

I second the thought of using a temporary siphon system to draw down the pond. Search on YouTube for videos. I used 2" PVC, and only glued the angles and cleanout on top of the dam, the 10' sticks were connected by temporary fernco rubber couplings. You will need a screen on the intake. Much better to let it run 24/7 by itself and not worry about a gas engine.

Neo07, you've gotten lots of good advice.

If you're worried about the immediate damage to the back of the dam, then I might look at geotextile road fabrics. I've been using it for several years now under limestone rocks on 24' watershed pipes, and a small emergency spillway. Erosion has pretty much stopped.

I have used the back of the backhoe bucket to compact a couple of core trenched below grade after stripping the topsoil (in excellent clay soil). They have not leaked, but I did not take shortcuts on the tamping which takes a lot of time. I used a sheepsfoot above grade. Do you have the topography to install a drain in the bottom of the pond (I used a 3" schedule 40 PVC pipe for my last pond and put a valve at the bottom of the pond in case needed later). Having a drain let me get plenty of clay from the basin to over-build the dam. I tried to explain the advantages of a steeply sloped pipe above ("One additional thing to consider is refitting you pipe with the exit end as low as possible..."). This allows a pipe to carry as much water as a larger pipe set with little drop when full because the water in the pipe pulls more water in like a siphon when the drop increases. The anti-vortex plate keeps the pipe from pulling air which decreases the pipes capacity. Having a drain gives you time to work slower with existing equipment. A dozer is nice for moving soil out of the bowl if things are not too wet. You also get a deeper pond. If you zoom in on the far left in the pic below, you can see the hole I dug that has the drain pipe in the bottom.

The bottom drain in my first pond was put in after the dam was done. The trench was dug, and when burying the pipe, each scoop was packed with the back of the excavator bucket. I did install the bottom drain on the new pond before adding the top 6 feet. I needed it to take incoming water during construction.

I did look into that but finding the stuff where I live has been tough...

Well thats very helpful, and will be fine tuned once they visit to see the site. When they come out ask about the use of that double wall HPDE corrugated pipe. I'm skeptical it and its joints are rated for a siphon effect in a downslope dam installation.

Looks like topsoil on the dam around the spillway, I like to pack clay around and on top to make sure it doesn’t wash next to pipe and bypass it....on the downside of the dam you might have to extend the rock and concrete so it don’t wash so bad