Siphon: Good solution for pond drainage

By Kevin Tate/Outdoors Writer

A simple plastic pipe construction can save pond owners countless headaches and dollars when it comes to lowering water levels for work, for maintenance or just for routine management.
Liquid moving down the line of a siphon under the influence of gravity literally sucks the liquid behind it up the line, overcoming the weight of the water on the uphill side in a perpetual flow that will continue until interrupted. To make this work, there needs to be more pipe on the downhill side of the rig than on the uphill side. The more the length of fall on the downhill side exceeds the rise on the uphill side, the more robust the system.
“Usually you want at least two thirds of the pipe on the downhill side,” Greg Briggs, of Porterville, said.
Briggs does land improvement work using bulldozers and other heavy equipment and is often called upon to work on ponds. Impoundments that have silted in and become shallow over the years or others whose owners simply want to alter or expand are best addressed after being drained. Cutting the levee with the use of a backhoe is one simple way to get the water out, but it can be an expensive process, one that can be largely avoided by going over the top with PVC pipe instead.
To set up the siphon, you’ll need at least one ball valve, a clean-out, several sections of non-collapsible pipe and some way to stop the water on the pond side while the pipe is being filled. The ball valve goes at the foot of the downhill run. The clean-out goes on top of the levee or at the highest point of the run.
The pond end can be capped with another ball valve, a one-way valve or any other contrivance that can be quickly opened. If you use a spring-loaded one-way valve positioned to let water flow into the pipe but not out, you can operate the siphon single-handedly. Any other solution requires a second set of hands.
The pipes themselves can be joined with standard glued PVC fittings or with flexible rubber joints and hose clamps. Either method works well, but the rubber joints allow some flexibility to the system after it’s assembled and are easily removed later.
With the ball valve at the bottom of the run closed and the pond end stopped, open the clean-out and fill the pipe with water. With the pipe filled, close the cleanout tightly. If you’ve used a one-way valve on the pond end, just open the ball valve at the bottom of the run and you’re draining water until you turn it off. If you’ve used something other than a one-way valve, both ends will need to be opened at the same time. Either way, this method is a simple, straightforward drainage solution.