I work for a conservation district and we are looking at building a dam on a guys place here shortly. It will be spring fed, approximately 2/3 of an acre and 8-10 ft deep. We want to incorporate a standpipe setup which will hook into an existing culvert that goes under a road behind the dam. My question is how do you anchor the stand pipe so it doesn't tip over come spring melt when there may be ice pushing against it? Any other advice would be appreciated too. Thanks.
If you can make the standpipe out of thicker walled pipe, and not the corregated culvert stuff, weld it together on site. If you are worried about ice, try and weld a few braces between the standpipe and the new culvert as high on the standpipe as you can, at a 45° angle. If you make the braces from 1/4 wall angle, it will hold up better than just flat stock.
One solution would be to have your standpipe actually buried in the face of the dam. In South Dakota we hae to deal with ice as you will. Place a small extra berm on the face of the dam where the stand pipe will be located. Then bury the standpipe in well packed clay, leaving only 6 inches or so of the pipe sticking out above the clay berm. Then place riprap or large field stone around the pipe inlet, so the water flow doesn't erode any of the soil. You will also want to place a trash guard of some type over the tube inlet to prevent it from getting plugged.
Thanks guys. We want to keep the standpipe out further in the water because it will be located fairly close to a road and there will be less chance of tampering or vandalism if it's far enough out that it can't be reached from shore. We'll try some angle iron braces and maybe some rock piled around the bottom to help stabilize it. I'll post some pics once we get the work underway. We are extremely wet here this summer so it'll probably be later in the fall before we get to work on this project.
In another thread Tim poured concrete around the base of the standpipe. TO help minimize erosion from water currents, and to help counteract the uplift of the pipe when it's empty.
Fastening my pond standpipe was easy, I made a big tripod and used stainless steel anchors into the bedrock. The hard part is (as you said) the concerns about ice and ice flows.
This has been in since 2004 and working great. Normal summer operation is drawing off the bottom with the level set by the standpipe in the dam. For winter I draw down to the pond standpipe. Since I have the springs overflowing year round, I put an insulated & counterweighted 32 gal plastic trash can over the standpipe in the pond. It has a couple of pvc pipes inside across the top so it can't suck down onto the pipe. The flow (5-10 gpm in winter) and the insulated cap keeps it from freezing.
I was planning on an exposed overflow down the backside (because we like the sound), but the more cautious and practical side of me is glad I went with the PVC culvert. No worries about erosion etc. If there is no reason for you to draw off the top, you could certainly skip the pond standpipe. I would still put a flap valve on the inlet side so you work on the outlet should you need to.
Hope that gives you some more ideas to consider. I have some other thoughts and observations on this design if you are interested, otherwise I'll save the paper.
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