Figure 5-3. Example of Head-to-Head Coverage Spray Pattern
In addition to considering how evenly water is applied, it is equally important to
consider the irrigation schedule, which dictates the amount and timing of the water
applied. Landscape water needs change with the seasons, and so should the irriga-
tion schedule. Many landscapes are watered at the same level all year, which is
unnecessary. Over-watering can damage plants more than under-watering and
can also damage streets, curbs, other paving, and building foundations.
Not only do proper design, installation, and maintenance of an irrigation system play
a significant role in landscape water efficiency, but there are also a variety of irriga-
tion technologies that can help reduce water use. For example, drip irrigation is a
highly efficient method of application because it directs water to plant roots at a low
flow rate, avoiding water lost to wind or runoff. This technology uses between 20 to
percent less water than conventional in-ground sprinkler systems.
There are also
efficient types of sprinkler heads that distribute water in larger droplets, avoiding
wind drift and increasing distribution uniformity. The Southern Nevada Water Au-
thority (SNWA) estimates water-efficient sprinkler technologies can reduce water use
by as much as 30 percent when compared to standard pop-up sprinklers.
ally, scheduling technologies relying on weather data, soil moisture, or other onsite
conditions apply water only when needed.
To capitalize on the water savings potential from these scheduling technologies,
the U.S. Environmental Protection Agency’s (EPA’s) WaterSense® program published
a specification to label weather-based irrigation controllers. WaterSense labeled
weather-based irrigation controllers (WBICs)
are independently certified to meet
plants’ watering needs without over-watering.
Gleick, Peter H., et al. Pacific Institute. 2003.
Waste Not, Want Not: The Potential for Urban Water Conservation in California
Solomon, K.H., et al. 2007.
Performance and Water Conservation Potential of Multi-Stream, Multi-Trajectory Rotating Sprinklers for Landscape Irrigation
neering in Agriculture. 23(2):153-163.
U.S. Environmental Protection Agency’s (EPA’s) WaterSense program. WaterSense Labeled Irrigation Controllers.