Pond Boss Forums INTRO Questions & Observations New Overflow/Spillway Just Finished

Hey guys, Just wanted to share a few pics of our pond and of the new overflow I just finished up. Here is were I started, 200' of 15" smoth plastic pipe and a concrete drainage box. Got it installed last spring and let the dirt settle for awhile.



I had to cut the inlet of the box about 8" lower that original picture. The box was designed for a curb drainage basin for the street department. Last week I prepped the dirt and set the wall forms. We poured the walls and the floor between rains. I think it turned out OK for a me and my FIL going it. Amateur concrete guys.







We got a 1/4" rain over the weekend and it is about 3 inches from the overflow now. My grandfather re-dug the pond about 15 years ago, and never installed an overflow pipe or spillway. It has been eroding for years and was time to fix it correctly. I didn't want to drain it and breech the damp to install an overflow pipe. I figured this was my best option. It will be nice to see the water flow into the creek and not flood the field below our pond. Here is a shot of the whole pond. I am standing by the pond inlet in the picture.

Does the ramp come from the lake? Or go to the creek? Seems like 2-4" of rain would swamp it? I have a 12-15 (never measured) culvert and I know in major downpours it gets buried a foot or more under water.. I have alot of runoff to deal with maybe you don't..

The water funnels out of the pond into the box, through the pipe, and exits at the creek down the hill about 200' away. In the second pic, you can see the tree line (creek) where the pipe exits. The pipe is buried about 4' under the corn field. This size of the pipe was recommended by the state for my watershed. Last spring, we received a few 2 inch + rains and I never had a problem with it overwhelming the pipe. I have about 20 acres of watershed that drains into the pond and it is all flat. It takes a few hours for the water to work its way to the pond after a rain. No major ditches that flow into it.

You may consider putting a trash guard at the drain - I would hate to have to try and clear a clogged drain with that distance. You may also consider putting rock or stacked stone at the drain to keep the water from trying to go around or under the concrete at the pond. It certainly looks nice and neat though!

I have a 15" pipe in my pond with about 25 acres of watershed. My emergency spillway has been used a couple times but never carried much water. My pipe is not as long as yours but has a lot of drop which means it caries a lot of water once it is full and the water forms a siphon. One suggestion is to add a top to your pipe entrance to avoid a vortex that will pull air into your pipe once the water level reaches the level of the top of the pipe. This will greatly increase the amount of water it moves.

I was thinking of adding a fish trapper/trash guard to the front of the funnel by the waters edge. I was wondering if I will loose fish when it is really flowing through the pipe. I just don’t want it to clog up with trash and restrict the flow. Hopefully in a month or so, the grass I planted takes and the roots will help lock in the soil around the concrete better. I figure I will watch it this spring and modify if needed. There is another emergency grass spillway on the opposite side of the dam. (SW side of the pond) It is 3” higher than the top of the concrete box. If a monsoon would happen and overwhelm the pipe, it could spill over that way. It is just not the preferred way.
Thanks for all of the suggestions.