We are in the early process of building a new home and including a 1 acre lake. Since all gutters and site drainage will be directed to the pond, the question has came up about how to address the 12" outlets for the pipes. The civil engineer has suggested installing a concrete head wall 1' above the waters edge. The only issue is that this design will not look natural and is expensive. The contractor has suggested that we submerge the 12" pipe below the freeze line of the pond, so that it is out of site.
1) Can anyone suggest the pros and cons on submerging the pipe below the water line?
2) Can we use PVC plastic pipe?
3) Should we have a head wall if we submerge the pipe?
I am no engineer, but if you extend the pipe into the pond below the freeze line, then I see no reason for concrete. My only concern would be having a pipe that can handle the worst rain that you might get, or an alternative high-flow route for the water in a deluge (some type of emergency spillway of sorts). You will need sufficient drop to the high water mark of the pond during flooding so that the water will continue to flow in the worst floods. PVC should be fine as long as its buried below the frost line and has sufficient continuous pitch to drain completely.
I agree with the advice from the previous posts. Plastic pipe works well for this application. I would put clean-outs on each 4" pipe so you can clean them if every needed. Make sure you put a rust resistance screen over the end that goes into the pond. Animals love going up these pipes and Pooh Bear could get stuck. I have fished around these pipes several times and they are a fish magnet. You would be wise to locate structure around this area and you won't be disappointed. Good luck!!
Two ponds, 13 and 15 acres on the Mattaponi River.
CB I live in south Alabama and did the same thing to make it look Natural. First I have a Metal roof and do not have to worry with any contamination. I used a 10" PVC green gasket sewage pipe. The pipe runs next to my drive going around to the pond and is about 2' under the water surface. I extended the pipe about 10' out into the water about 2' off the bottom. I do not have any silt coming down the pipe and do not have any issues about it being under water. I did not use no cement and just packed the pipe down and covered it with good clay compacting it well. If you will look in the attached pick the Piping is run thru the trees to the right front of the house. One look at the picture tell you how naturally it looks. I did a ruff edit also in paint to show how the piping runs underground from where it leaves my yard.
Thanks to everyone who has taken the time to respond. Your answers are great! At this time, I'll communicate to the contractor the following information. Please feel free to add additional comments & suggestions.
* PVC green gasket sewage pipe (sized properly to drain sq/ft of roof) * Extend pipe into the pond below the freeze line (possible 2' off the bottom) * Pack pipe down & cover it with good clay, compacting it well * Install clean-outs on each section of pipe to assist in cleaning when needed
Tums, did you extend the pipe out 10 feet or 10 inches? Your post mentioned 10 feet. Is there an advantage of extending it out this far?
It originally was just a short distance and I learned this was a mistake for my situation. The pipe was to close to the bottom at the edge and the currents in heavy rains started blowing out a hole in the bottom. This was making a silt deposit sand bar in front of the pipe and creating a hole issue. I made changes to get it in deep enough water and far enough out to no longer effect anything. It actually turned into a good little fishing spot as BG tend to bed in the area around the pipe and use it for cover. PS Remember If your pond water level fluctuates and ever falls below the reach of your pipe it can cause problem. The run off water coming from the end of you pipe will start to wash out a hole. This can possible cause a ground stability issue near the edge of a pond. Cemented in pipes at the edge have to be built to account for this also.
whould you need a rat guard if the outlet pipes are to be submerged?
Never had an issue with rats here in 3 years and my submerged pipe is uncovered. Being over 10' from the bank underwater I do not think any rat will be out there roaming around. I have wondered if I would ever get a turtle in there and die though.
Blair I am near the southern edge of muskrat range and have seen none in this county in 43 years here. I have otters ,beavers, snakes & turtles that probably check the pipe out though. That is why i stated about a turtle dying in there. More than just a rat to think about. I just count on what goes in will come out since my water is coming down a steep hill. If the pipe ever did stop water would just run out in my yard until it was fixed.
I would also install a rat guard on the outlet. I do not think that you need to go overboard on the cleanouts.
Actually if he has trees near the house he could get leaves and twigs into the pipe if he doesn't have a leave guards on his gutters. All it would take is a twig or two jammed sideways with leaves behind it to cause problems.
Leave guards on gutters are a must though if you have trees IMHO. So if he had those he should be good.
If pigs could fly bacon would be harder to come by and there would be a lot of damaged trees.