The Green Room

Soaking up the power of rain

By Don Moseley on August 15, 2012 1 comment

Summer is an ideal time for those with a green thumb, but as homeowners and gardeners know, some plants need a lot of water. In fact, landscaping can account for up to a third of residential water use. By some estimates, up to half of the water used for business and homes is wasted due to water inefficiencies in outdoor landscapes. That’s particularly troubling when such a large part of the U.S. is in a drought.

Santa Fe, N.M., is one city that struggles with water scarcity. For a community that receives less than 14 inches of rain a year, water conservation is important. That’s why our Walmart store in Santa Fe is now capturing this rainwater and saving it to water the store’s landscaping.

Here’s how it works: When it rains, water is collected from the store’s roof and stored in an underground tank that holds 113,000 gallons of water. This storage tank is used to irrigate the store’s landscaping, which was carefully designed with drought-tolerant and native plants. A weather-based control system measures conditions to give the plants just the right amount of water they need – no more, no less.

This system will provide 69 percent of the water the store’s landscape will need in an average year, reducing water needed from city water supplies. For years with above average rainfall, the system could provide 100 percent of the water needed for the store’s landscape.

The rainwater harvesting project in Santa Fe is the most recent effort in a series of outdoor water conservation systems we started in 2005. Over the last seven years, we have learned a lot in this area and have developed some best practices while eliminating those that didn’t work as well as they should. As a result, we have a new set of guidelines we use for projects like the one in Santa Fe, or a similar one at a store in Flagstaff, Ariz., that captures rainwater to irrigate the store’s Garden Center.

What best practices do you have for conserving water outside your home or small business? Collecting and storing water in a rainwater barrel is one simple way to save up on a rainy day, but there are a number of other ways to conserve. Here are some suggestions from the U.S. Environmental Protection Agency’s WaterSense program:

• Use plants that require less water and are native to your region.
• Water in the early mornings (from 4 to 7 a.m.) to reduce evaporation.
• Sweep your sidewalk or driveway instead of hosing them down.
• Raise your lawn mower cutting height to reduce water evaporation and rapid grass growth.
• Consider installing water-saving technologies, such as a watering timer or sprinkler controller.