One key point of the Kerr Center livestock program’s approach to water management is, as much as possible, to take the water to the cattle in the pasture. This allows cattle to make more efficient use of forage, and also minimizes the amount of ground sacrificed for “lanes” to and from watering points – both of which reduce erosion.
Boiled down to the bare essentials, we want to get the water from here…
The next refinement is to let gravity carry the water downhill, instead of relying on power-sucking pumps.
To run downhill from a pond, though, the water usually has to first run at least a little ways uphill. This is because it’s not generally a good idea to drain a pond from below, and because the downhill end of a pond is where the dam is. This is where the siphon principle comes in.
A siphon is simply a tube or pipe that’s higher in the middle than at either end, and with one end lower than the other. Once the tube is completely full of water, it will continue to drain water from the higher end out through the lower until blocked (or until enough air somehow gets into the tube to interrupt the flow of water).
This is exactly the situation when a water line runs out of a pond, over the dam, and downhill to a watering point below the pond.
To set up a siphon in a pond, first insert the intake. The Kerr Ranch siphon intake is shown in the photo below. The uprights have several holes drilled in them for water intakes, but they are capped at the tops, and the horizontal sections are intact, to prevent blockage.
Once the intake is in place, close the valve on the outlet end.
Then, use a pair of valved uprights at the high point to prime the siphon.
With both valves open, pour water in one upright. The water will fill the siphon tube from the intake to the closed valve at the outlet end, forcing air out through the second upright.
When water starts coming out of the second upright, all the air has been forced out, and the pipe section is full of water from intake to outlet valve. Close both priming valves, open the outlet valve, and watch the water flow!
For a more detailed and technical guide to setting up gravity-flow watering systems for livestock, check out this free resource from the British Columbia Ministry of Agriculture and Lands: