Pond Boss Forums POND CONSTRUCTION Building a dam new dam

I am beginning to build a dam in a few weeks.I was wanting to know if the water source from the valley is on the south side& the overflow pipe is on the south side could I simply use a spillway instaed of a pipe?There is 25 acres that drain across my property.Can anyone give me any advise /or know anyone else that has this similar set up. The pond will be approx. 3/4 acre

Grant,

The overflow pipe is also called a trickle tube in some quarters, because its most valuable use is to allow slow, continuous flows of water to pass through the dam. The greatest risk to an earthen spillway is not the acute, rapid, but short term flow of water caused by a major storm event. In fact that is what the earthen spillway is designed for. If this spillway is covered with a sod forming grass, then the grass lays over under heavy flows and protects the earth from eroding for short term (hours) flows.

The reason that earthen spillways fail is when a trickle tube is not installed, and the earthen spillway must pass slow flows (trickles) of water for weeks on end. Under these conditions the water will eventually find its way to start eroding the soil, even if it is grass covered. Once the water cuts into the soil, erosion can occur very rapidly and eat its way up to the dam and cause a breach. The only way to use an emergency spillway for both slow and heavy flow events is to completely armor it with appropriately sized/placed rock (with an erosion control fabric beneath) or constructing it out of concrete. The tube will be much cheaper than these options.

Thus a dams most important features are a solid and well compacted core trench, an appropriately sides (and installed) tube, and a properly designed and maintained emergency spillway.

can i put my overflow pipe on the south side?

Grant,

Sorry I didn't answer your main question. There is actually another similar thread in this section as well.

Generally there should not be an issue with where the outflow pipe is in relation to the inflow pipe. The only concern I can think of is if your inflow water might be heavily loaded with debris or sediment that might plug up your tube over time.

In most cases the overflow pipe is placed so that it drains into the normal watercourse the water would follow if the dam weren't in place. The key is getting the water passing through the dam and back into its normal course with as little erosion potential as possible. On our ponds we also place some large rocks under the outlet of the tube to help slow and disperse the flow of the water, so that it doesn't cut down or back into the dam.

I'm curious as to how your topography works such that you would have water both entering and exiting from the same side. They must be some distance apart with an elevation drop between them.