EA New Homes Measures Guide - Earth Advantage

2012 Earth Advantage Residential
Measures Resource Guide
8.2.1
Low-Volume Irrigation System
Accountability Form: Landscape
Energy
Health
Materials
Water
0 0 0 0 2
Description: Install a low-volume irrigation that slowly applies water to a plant's root zone. It is a form of micro-irrigation that includes drip
and low volume irrigation systems.
Land
Benefit: Up to 50 percent of municipal water use in the summer is for outdoor irrigation. That's also when rainfall is scarce and reservoirs,
lakes, and streams are at their lowest levels. Low-volume irrigation systems can use 75 percent less water than sprinkler systems during
the time of year that water supplies are lowest. Second, reducing water demand lowers the energy and environmental impacts associated
with collection, transportation, and treatment needed to deliver water for outdoor irrigation use. Third, installing a low-volume system
requires the thoughtful use of drought-tolerant and low-water plants appropriate to your site. Appropriate plants have a higher success rate
and generally require fewer fertilizers and other artificial aids to establish themselves. This reduces the environmental consequences of
fertilizer runoff, as well as the embodied energy to manufacture, transport, and dispose of the fertilizers themselves. Finally, installing a
low-volume system saves money on the water bill.
Low-volume irrigation is more effective at meeting the plants watering needs. There are water savings for the homeowner over the lifetime
of occupancy, and reduced peak summer demand provides savings for the municipality. Low-volume systems are adaptable to the
landscape and can be easily removed when irrigation is no longer required.
Better systems will have higher up-front cost, but will be offset by reducing water usage. Planning and design are needed to determine
system requirements including performance, minimum efficiency standards, and controller features. As with any irrigation system, regular
monitoring is required to ensure proper operation.
One negative aspect applies to all types of irrigation, tubing for low-volume systems is often made from polyvinyl chloride (PVC), which is a
significant source of toxins during manufacture and disposal. If possible, select alternatives to PVC such as polyethylene.
Installation should be performed by a certified irrigation specialist and conform to local water use ordinances.
The average established shrub zone needs approximately 9,300 gallons per 1000 sq. feet each growing (peak) season. Low-volume
irrigation has proven to save 60 percent to 70 percent water over the course of the season with no affect on plant health due to efficient
saturation of the root zone. This is a possible savings of 5,000 - 6,000 gallons per 1000 sq. feet of shrub area installed with low-volume
irrigation.
Verification: EA Rater will recognize a low-volume irrigation system by operating the system. System to be operated by technician to verify
no overspray.
8.2.2
Hydro Zoning: Grouping of plants and lawn for watering
Accountability Form: Landscape
Energy
Materials
Water
0 0 0 0 1
Description: Establish separate watering zones for lawn and other plants. Each zone is designed to deliver the appropriate amount of water
to each plant type. This includes selecting proper water delivery methods, such as sprinkler heads or drip emitters.
Health
Land
Benefit: An irrigation system that has been zoned to provide separate watering patterns for shrubs and lawn will use less water than nonzoned
systems. Because lawn requires more water to survive, the over watering of plants will occur if separate systems are not installed. A
study in Eugene, Oregon, showed that a typical lawn needs 18,600 gallons per 1000 sq. feet each growing (peak) season. Analysis
indicates that established shrubs need 50 percent of the water that lawns need. This is a potential savings of 9,300 gallons for each 1000
sq. feet of shrub plantings.
Verification: EA Rater will confirm that plants and turf are grouped into similar water needs for each irrigation zone by turning on the
irrigation system to confirm that the system delivers water to each planting zone.
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