Garden expert gives rain harvesting tips
Photo courtesy of Jacqueline A. Soule – By adding earthen berms, rain runoff is slowed and encouraged to sink into the soil around plants that need water rather than running off into the street.
by Jacqueline A. Soule
For thousands of years, people living in arid climates have captured and stored rainwater and snowmelt. Rainwater harvesting not only is ecologically friendly, but is easy on the wallet by helping you to save on your water bill.
Harvesting rainwater is simple. The only difficulty is that modern homes are constructed to shed water onto the street and down storm drains. Rainwater is thus treated as a waste product. To stop the runoff of this precious commodity, you'll need to catch and hold the rain on your own land either by passive or active means.
Passive methods of rainwater harvesting include strategic placement of plants and catchment areas. Active harvest includes a storage tank and distribution system. Current restrictions in Colorado regarding active systems may prevent residents from pursuing those methods of rain harvesting. However, every gardener can engage in passive harvesting.
Read an overview of Colorado regulations regarding rainwater harvesting >>
Begin by drawing a scale map of your property. Include the house, sidewalks, patios and any other impervious surfaces that will shed water onto the landscape. Sketch in arrows to indicate water flow directions across each surface. Mark landscaped areas, types of vegetation and the number of plants. A plan will help you decide where and how to direct rainwater, add berms and store water.
Place plants where the water falls, just below the roof edges. An ample planting of decorative ground covers or low growing shrubs will help catch the water. Incidentally, they'll also help reduce the heat load on your home and reduce soil splash on walls.
Dig a pit
I experimented with my own catchment in the landscaping. The rainwater from the front of my 1,300-square-foot house is guided to a 3-foot deep pit where it seeps into the soil.
The pit is lined with river rocks to help keep it from collapsing. A mere quarter inch of rainfall will fill it, and I use my soaker hose and garden hose to irrigate new plantings.
Catchment areas hold the water, giving it time to soak into your soil. In most yards, this involves building soil berms across the water draining from your yard. Curve the berm to make a nice basin for a tree or shrub planted on the upslope side. Berms and roof line plantings should include plenty of added compost to help the water soak into the soil.
And, if you have rain gutters, instead of letting the water run down the drain, change them to direct the flow out onto the landscape. Add berms and catchment basins so the downspouts water a series of plants or a series of low-lying areas.
Jacqueline A. Soule, Ph.D. is a botanist, writer and educator. A member of the Garden Writers Association, she lives in Tucson and writes gardening columns for a number of newspapers throughout the Southwest. A self-avowed "Darwinistic" gardener, Soule prefers plants that need as little care as possible while providing color, texture and movement in the landscape.