Irrigation Techniques: Irrigating Small Lots
|By TRACY TUCKER|
When reminiscing of youthful days gone by, many people are reminded of playing tag with neighborhood friends, climbing trees, and chasing the family dog. More often than not, these recollections usually take place in the great expanse of our childhood backyards.
However, these images are quickly becoming a thing of the past as larger homes are being built on smaller lots, leaving little room for backyard playgrounds. Fueling this trend are the rising costs of land and reduced homeowner interest in maintaining large outdoor landscapes.
There are several techniques you can use to irrigate small landscapes, from the use of new-and-improved spray heads and nozzles to pressure regulators and check valves. As all of these ideas prove, don’t be afraid to think small.
Matched precipitation rate spray nozzles
Matched precipitation rate nozzles control the flow of water as well as the pattern and radius. Quarter circles, half circles, and full circles can all be used together on the same zone, because the nozzles themselves ensure that smaller patterns deliver correspondingly lesser flow. This helps conserve water—something important to consider with water conservation on everyone’s mind.
Older nozzles watered with the same flow rate regardless of the nozzle pattern and radii. For example, a nozzle with a half-circle pattern sprayed the same amount of water as a nozzle with a quarter-circle pattern. Although the quarter-circle was watering a smaller area, it was delivering the same amount of water, therefore overwatering the space. To counteract this effect, zones and run times had to be manipulated in complicated ways.
Multi-stream rotating nozzles
Pressure regulators and check valves
The introduction of spray heads equipped with pressure regulation represents another leap forward in reducing water waste. By helping maintain a constant outlet pressure, these pressure-regulating devices reduce misting and fogging, so that more water reaches the soil. Not only does pressure regulation help maintain a constant outlet pressure, it does so regardless of the type of nozzle used. In addition, these devices reduce pressure loss if the nozzle is removed or damaged.
Check valves were developed to prevent low-head drainage in tight areas. When an irrigation system is shut off, water remaining in the lines tends to flow to the lowest head in the system, where it then flows out. This not only wastes water, but the runoff it creates can damage the landscape due to flooding or erosion. A check valve closes off the sprinkler when the system shuts off, preventing any remaining water from escaping.
Drip irrigation and low-volume pop-ups
Low-volume pop-up spray heads are also ideal for small lot sizes. Installed on the same line as regular spray heads, these spray heads can be equipped with drip emission devices to provide the benefits of low-volume irrigation in a shrub area or narrow space without the installation of a separate drip irrigation line.
As lot sizes shrink, irrigation systems are affected. Rotors, which throw water too far to be effective for smaller properties, are being moved to larger common areas such as neighborhood parks. In residential turf applications, a variety of water-efficient spray zones are becoming more prevalent.
Editor’s Note: Tracy Tucker is a product manager for Rain Bird’s landscape irrigation division.