Pond Boss Forums POND CONSTRUCTION Building a dam Pipe overflow?

My pond is an excavated hole in the ground (no Dam). I want to make a culvert overflow so that when the pond reaches a certain level it will start to run off. Is it possible to put an elbow on the pipe to take the water from deeper in the pond? keep in mind there is little difference in the elevation from the level of the main pipe to the outflow. I was thinking that once the pond level reaches the horizontal pipe it would flow out and the pressure from the pond water would keep the up tube full to the same level as the pond itself. Thanks for your help.

My Dad has a drain in his garage made from a 55 gal drum that has used this method (high level outflow pipe with an elbow down into the basin) of drain for 45 years. He put it in this way to try and keep sediment from washing cars from entering his drywell.

It works as you hypothesized - as the water level reaches the bottom of the outflow pipe, it also rises inside the down-turned elbow and begins to exit the basin.

It's not actually an elbow - he used a "T" with a cap on top so he could access the vertical pipe from the top in case it needs cleaning. I would recommend the same approach in your pond overflow in case the vertical pipe gets clogged.

Note that the vertical pipe will always have water in it and will therefore be subjected to freezing (and quite possibly busting) if temperatures get low enough for that.

Thanks Theo for the info. Now I need to think about the freezing aspect of the project. It doesn't get that cold every winter but there are times when the pond will get a thin layer of ice on it. I was thinking about using plastic, do you recommend using metal? Also I was going to use an elbow because I wanted to use a 45 degree entry into the pond. do they make a 45 degree T? I like the idea of being able to access the pipe through the T. Thanks again for any help.

bassandgrass,
You can get a Y fitting that is straight through with a 90 out the side.

If your freezing never amounts to more than an inch or so I wouldn't worry. To be safe use sch. 40 pipe & fittings where it is above the water.

As Ric suggested, I'd use Schedule 40 (PVC). Large metal pipes would also be susceptible to freeze damage (more/less - I don't know) and are heavier and harder to work with. If you get a freeze event every few years that trashed the plastic pipe at the waterline, you can cut it off and glue in replacement pieces as needed pretty easy. It would be much harder for a non-plumber to do the same with metal (heck, find ANYBODY not using plastic for soil pipe in houses nowadays!).

I suggest you see what fittings are available and plan your drain around them. In addition to looking at places such as Lowe's and Home Depot, look for someplace specializing in drain and tile supplies. Our local supplier is titled something like "Discount Tile and Drainage" - they had EVERYTHING we needed for our pond drain, at good prices.

Paint any plastic pipe exposed above ground/water to help prevent deterioration by ultraviolet light. There's a post here somewhere in the archives that talks about sunlight resistance of various types of plastic pipe, but I'd paint whatever I used, thinking it couldn't hurt.

Thanks for the great tips. I realize there is much to be learned from you guys on this forum. I will start to refine my plan for this project soon, I appreciate your input.