Sprinkler irrigation is the most common method of landscape irrigation. Find DIY sprinkler irrigation facts and information on sprinkler irrigation components.
For many years it was considered the only effective way to uniformly apply water over large areas such as athletic fields and lawns. In spite of the issues of large quantities of water to being lost to evaporation, sprinkler irrigation remains the most common method of irrigating landscapes, including drip irrigation systems. It is quick, easy, and convenient. Changes in sprinkler head design combined with proper system design, installation, management, and maintenance improve the water use efficiency for sprinkler systems.
The simplest system requires a portable sprinkler attached to the end of a garden hose and an outside water tap. This is adequate for small areas to be irrigated and in regions where irrigation is needed infrequently. In arid regions, such as xeriscapes, and increasingly in humid regions, more complex inground systems with automatic controllers are being installed.
Inground systems are more expensive to install, but will provide advantages over the hose and portable sprinkler. With an inground system, you need not drag a hose to the site to be watered. You will avoid getting wet from placing the sprinkler in just the right spot.
Sprinkler System Components
Shutoff valve: The first component of an inground sprinkler system, beginning at the water source, is a main shutoff valve, allowing srepairs to any portion of the system.
Filter: The next element in the line should be a filter which removes any particulate matter in the water. Particulates may be hard water scale from upstream pipes, material not previously filtered from the water, or soil that entered the pipes following breaks in water lines or construction that replaces or adds pipes. A filter allowing back-flushing is a good investment but must be properly installed to work correctly.
Pressure regulator: After the filter, a pressure regulator is often included, especially for low-volume irrigation systems. In sprinkler systems this maintains a consistent water pressure, allowing uniform water applications with consistent droplet size.
Valves: Valves enable you to install multiple irrigation zones in the landscape. Each valve controls a single zone, allowing different plants to be irrigated according to their needs. Trees and shrubs can be irrigated less often but more deeply than plants in the flower border or the lawn. Each of these plant types can be on a different zone to allow proper irrigation. Independent irrigation zones allow irrigating the zones at different times to prevent excessive reduction in water pressure, which results in inefficient irrigation.
Before installing the valves, run water through the system to flush sediment from the lines. Sediment that remains in the lines can cause failure of automatic valves.
*Tip- In cold-weather regions drain water from inground pipes at the end of the growing season to prevent damage from freezing. Use compressed air to blow out the remaining water.
Valve boxes: These are set into the ground and will allow easy access for testing, maintenance, or replacement of valves installed in the boxes. * When installing the boxes, be sure to allow room for valve repairs or replacements. The boxes may be insulated during the winter to protect the valves from freezing. The boxes are inviting habitats for snails, spiders, wasps, and bees, so be careful when opening or working near valve boxes in regions where Africanized bees may colonize the boxes.
*Tip- Use a manual-on, automatic-off valve uses a times, so it shuts off after a preset interval. This allows you to switch on the system any time, safe in the knowledge that it will shut itself down.
Backflow prevention device: This is installed next to protect the home potable water supply from reverse flow. This antisiphon device prevents contaminated water fro entering the home water supply when water pressure in the main lines is decreased. Several forms of this device are available and mandated by municipal ordinances. They are a good idea to use as they are a good investment for the safety of your home and neighborhood water supplies.
There are several types, but not all types are allowed in all municipalities. You should check with your city ordinances to determine which one you may use. Some are installed after the valves, while other may be installed before the valves. Others may need to be installed so that they are higher than any downstream element in the system. Some items must be installed by a state certified installer.
Piping- Piping next to the sprinkler heads comes next. These pipes should be buried deep enough to avoid freezing or they must be drained each winter to prevent bursting. Pips size must be large enough to carry water to all sprinkler heads, while maintaining sufficient pressure and flow volume for the last sprinkler to operate properly. Consult with a certified irrigation expert for proper installation and requirement.
Sprinkler Heads- You may want to choose sprinkler heads for large flat areas with no water runoff problems. They will provide a high application rate so that the water is applied quickly. Sloping areas or areas where water runs off before wetting the soil benefits from rotor-type heads. Proper placement of sprinkler heads is extremely important to maximize system efficiency. In general space them so that water from one head overlaps the pattern from the adjacent head (head-to-head spacing).
Match the water delivery rates from each head in a irrigation zone. The sprinkler heads must be high enough above the grass and other vegetation so that their water is not blocked or deflected. Risers and pop-up heads allow for proper clearance.
Timers or Irrigation Controllers- These are optional elements for the irrigation system. They allow you to program and automate the beginning and ending irrigation time for each zone in the system. There are also rain sensors and soil moisture measurement devices to allow irrigation cycles to be skipped when it is raining or adequate moisture is available. These adjustment devices will ensure that water will not be wasted.