Pond Boss Forums POND CONSTRUCTION Building a dam Overflow Pipe or Not

After reading the thread I am not seeing how big the pond is and how large is the watershed topography. Smaller ponds in my area commonly have plastic overflow pipes (4"-8" dia) that are laid horizontal and buried around 12"-24" below the ground embeded in the free board as the pipe leaves the pond. Water is drained to a ditch or another outlet tile.

Outlet pipe structures are intended for releasing water from common rain events. Most spillways are for emergency high water surges. Siphon pipes are good for fish, weed, and shallow shoreline management.

A wide, deep high water earthen or cement spillway designed with proper slope and soils for the velocity of watershed water could be used for your pond if budget is critical. It is easier and cheaper to plan and design a spillway than fix one. Devote good money to better spillway design and construction, rather than the outlet pipe structure. Spillways have a tendency to erode, wash out, get perforated by digging burrowing animals. A wide well built stabilized spillway IMO, would handle more water release than a outlet pipe structure. A larger volume spillway IMO should have rip rap or cement on both sides to help reduce any possible water movement causing erosion during high water events. A cement sluceway on the back side of the dam, if the spillway in on the dam, might be appropriate. The emergency overflow spillway for my pond is not on the dam.

The drainage ditch to move water from your water spillway would not have to be ripraped the entire length; just riprap until the water is . It could be grassed and have gentle sloping sides (4:1 marginal - 5:1 better) where you could mow it or keep the brush out of it (slow sloped surface ditch).