Page 161 - WaterSense at Work

WaterSense at Work: Best Management Practices for Commercial and Institutional Facilities
Irrigation Association (IA). Falls Church, Virginia.
The efficiency of an irrigation system is dictated by many factors, including human,
mechanical, and environmental components. Implementing mechanisms and prac-
tices that increase an irrigation system’s efficiency could save a property more than
half of its outdoor water use. In landscapes around the country, a significant amount
of water is lost from evaporation, wind, or runoff due to improper irrigation system
design, installation, and maintenance. Eliminating this waste requires trained profes-
sionals, appropriate irrigation schedules, and efficient technologies. Additionally, the
landscape itself (e.g., plant palette, soil type, etc.) plays a role in irrigation water use
and provides the potential for additional water savings. See
Section 5.2: Landscaping
for more details.
One of the most important concepts associated with irrigation system efficiency
is distribution uniformity, or how evenly water is applied over the landscape. This
concept is illustrated in Figure 5-2.
Extra water is often applied if the system is not
distributing water in a uniform manner. Without proper distribution, the landscape is
watered to keep the driest spot green, over-irrigating other areas. Figure 5-3 provides
an illustration of head-to-head coverage, which is a practice to increase distribu-
tion uniformity. Using this practice, each sprinkler head (depicted with numbers 1
through 4 in Figure 5-3) is positioned so that its spray arch just touches the head of
each surrounding sprinkler. This ensures that there is sufficient overlap and no areas
are without coverage.
Figure 5-2. Good and Poor Distribution Uniformity
Good Uniformity
Application Depth
Never Perfect)
Poor Uniformity
Application Depth