Using a pond for landscape irrigation as opposed to a well or public water system has its positives and negatives. Pulling water from a pond to irrigate your lawn or garden can be an economical use of water as long as the pond is large enough, and self-sustaining enough through rainfall or underground springs to meet your needs. You still need a pump and piping, and you will definitely need a plan before you get started.
If the pond can provide enough water for irrigation, start with a scale drawing, showing all of your plants, where the pond is located and a rough sketch of either where the piping will be buried or how you plan to get the water from the pond to the plants. After you have a rough sketch, you need to make a list of the materials you will need including the pump, pipe, connecting valves and timers if the system is going to be underground. If the system is above ground, your work has just been cut in half. You also need to provide electricity to the pump or purchase a solar powered pump with a 24V battery backup system.
Tying Into Your Pond
Normally an irrigation system is tied to an outdoor faucet, your home’s water supply line or a brown water valve. Drawing water from a pond for irrigation involves incorporating a pump to pull the water from the pond and a means of directing the water to where you need it. A general rule of thumb is that a one acre pond can irrigate 10 acres of lawn. You can either use a submersible pump, or one that sits in a pump house to the side of the pond and pulls water and directs it through an appropriately sized pipe and control valves or hose.
Calculating Water Need
It can be a bit difficult calculating the amount of water you have with how much water you need. While the calculations are all very scientific, an Evapotranspiration or ETO valve or irrigation controller can help make the calculations for you, but it is generally not very accurate. The formula to determine the number of gallons needed per day is: (ETO x PF–plant factor x SF– square feet to be irrigated x 0.62) / IE–irrigation efficiency = gallons of water per day. Your local extension service may also provide ETO data for your area.
Pond Irrigation Tips
Never invest in an expensive pump, pipe, valves, timers, sprinklers hoses or anything else until you have a design plan and can accurately determine if the pond can actually meet your needs. You need this information in order to know why type of pump to buy. If you live in a dry area where you really can’t rely on the pond to provide a sufficient water supply when you need it, you can also back fill the pond from a well or cistern if necessary, but this does require another pump and more pipe.