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IRRIGATION LAWN-LANDSCAPE-SPRINKLER-INSTALLERS
Zoned properly
Landscape Sprinklers should be zoned
properly so lawns can be watered separately from trees, shrubs
and flowers. Also water vegetable beds and rose gardens
separately from lawn areas. Design sprinklers to "line out"
driveways, walks, roads and non-irrigated areas. Sprinklers
should be next to hard surfaces to throw water onto landscape
areas. Avoid a design where the sprinkler heads shoot from the
center towards pavement to avoid runoff water waste. Design
irrigation zones so water from one head reaches the neighboring
head's. Too much space between sprinkler heads creates dry
spots. Sprinklers are best installed in a triangular or square
pattern to insure "head to head" coverage. Sprinkler heads that
do not overlap cannot be expected to water the intended area
properly. Install only as many heads per irrigation zone as the
water pressure will allow.
Pressure Regulators
Irrigation heads are designed by
manufacturers to apply a certain amount of water over a specific
area when performing within a certain operating pressure range.
Installing more heads than the water system will handle results
in dry spots. Symptoms of low water pressure often appear as
donuts of green grass around the sprinkler head with dry areas
between heads. Avoid oscillating sprinklers and sprinkler heads
that produce mists or fine sprays. High water pressure should be
reduced by adding pressure regulators to the system. Install the
same type of head with the same precipitation rate within each
zone. Mixing heads within a zone leads to uneven water
application, unsatisfactory plant growth and often runoff water
waste. The water delivery rate of rotary, spray heads and impact
sprinkler heads is different. Impact heads deliver as little as
1/2 inch of water per hour, while pop-up spray heads may apply
up to two inches of water per hour. Long, sloping turf areas may
require several different sprinkler zones; each line of
sprinklers, controlled by a valve, is called a zone.
Check Valves
Irrigation zones should be installed
along the top of the slope, rather than up and down the slope.
The slope may require two or more lines of sprinklers, each
controlled by its own valve. Because water runs downhill, the
bottom of the slope tends to receive more water. Adjust
sprinkler zones running along the middle and bottom of the slope
so they apply progressively less water than the sprinklers at
the top of the slope. Watering for the same amount of time in
each zone wastes water. If possible, install water-conserving
devices such as check valves, pressure regulators or climate
sensors (i.e. rain, temperature and wind sensors). These suspend
irrigation under unfavorable weather conditions. Consider water
efficient drip irrigation for shrub borders, flower and
vegetable gardens. Drip irrigation exceeds 90 percent efficiency
whereas sprinkler systems are 50 to 70 percent efficient.
Mixing heads within a zone
leads to uneven water application, unsatisfactory plant growth
and often runoff water waste.
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