May 3, 2013

Save water in your garden!

It's typical that water use for irrigation averages more than 50% of total residential consumption. Clearly, addressing the outdoors is as important as what you do with WaterSaver plumbing fixtures indoors.  Here's how:

PREPARE:  Preserving soil quality is important for water efficiency. Maintain as much existing vegetation as possible;cordon off and preserve areas that have value in terms of drainage and plants. Commit to losing some lawn. The EPA’s WaterSense program recommends limiting turf area to a maximum of 40% of the site, balancing the rest with drought-resistant plantings and permeable surfaces.  Designing a landscape to conserve water—xeriscaping—requires choosing plants that will thrive in your region and your project’s particular micro-climate; limiting the turf areas; making sure the soil on site will promote water absorption and deep root growth; and, if irrigation is installed, using an efficient system. Water-efficient landscaping and irrigation should combine a mix of plantings and irrigation components that will minimize the amount of water needed to maintain an inviting environment. 

WATER SMART: Irrigation systems should include separate zones to accommodate different watering requirements, drip irrigation for plant beds, and rotating sprinkler heads for turf areas. Avoid duplicate coverage and watering paved areas and buildings. Surface runoff can be reduced by keeping the precipitation rate from sprinklers below the soil’s infiltration rate, and establishing different zones for the tops and toes of slopes.  Over watering is a major problem mostly due to error in setting and maintaining timer-based controllers. While the cost of a sophisticated system will depend on the number of zones and specific features, it isn’t necessarily steep. Check the testing and performance summaries and technical reports on a number of systems at ( On small sites, or on sites that have hardscaped areas that don’t require any water, micro-irrigation is an option. These are low-pressure systems that spray, mist, sprinkle, or drip water close to a plant’s root zone through plastic hose lines or small emitters. These systems lose little water to evaporation, wind, and runoff, and they also can be used within multi-zone designs.

Rain pillow system for easy crawlspace and under deck installations.
SAVE RAIN:  In areas where rainwater is available, rainwater harvesting is gaining attention as an alternative source of irrigation water. These systems can be as simple as a rain barrel connected to a soaker hose or as sophisticated as underground cisterns connected to a pressurized irrigation distribution system. The amount of water that can be harvested is determined by calculating the size of the roof area and the typical amount of rainfall.  Harvesting, or redirecting water from downspouts to plants (along with utilizing porous materials for non-planted areas) keeps runoff out of the sewer system, easing stress on infrastructure while allowing more water to percolate back into the groundwater. Water from a small roof area can simply be sent to a lawn or planting bed; larger amounts can supply a specially designed rain garden that is graded to collect water, filled with well-drained soil, and planted with species that can tolerate inundation as well as drier periods in between storms. Some local governments offer design assistance or even grants to expand the use of rain gardens and other techniques that treat rainwater as a resource, not a waste product.