Recycling Rain Using Rain Water Harvesting Techniques
There seem to be two schools of thought on rain water. One is that it is our enemy and needs to be removed from our property as quickly as possible.
The second is that water is our friend, and we need to capture it and let it sink back into the soil. Clearly, moving it away from the house is important, but shipping it out to the storm sewer system causes problems in the ocean and wastes a natural resource.
Seeing rain water in this positive way, and adapting our approach to our landscaping projects is also known as Rain Water Harvesting, and in his book of the same title, Brad Lancaster, outlines several techniques that we recommend here at The Yard Fairy.
2. Minimize the use of non-porous materials such as concrete in the landscape. Instead use gravel, decomposed granite or flagstones set in the ground. A new generation of permeable pavers is also a good option, and qualifies for LEED points.
3. Collect rain water falling on the roof of the home via the gutter system in rain water barrels. One inch of rain falling on a 2,000 square foot roof will generate 1,250 gallons of water. Even with our fairly small amount of rain (an average of about 6″ over the last three years), you can’t hope to collect it all this way, but by installing one or two 75 gallon rain barrels connected to the downspouts of your home, you will have some extra water for use in your garden during the dry season.
4. Mulch the soil around plants and trees with a wood chip bark 2-4″ deep. Mulch is much more able to absorb water than many of our soils in San Diego county, so it acts as a sponge to collect the rain and then release it to the soil as it the soil dries out.
5. Work with the natural flow of water in your garden by sculpting the soil and creating swales that can then be turned into dry stream beds. Slow the flow of water in these streams using larger rocks or boulders. Plant succulents and grasses in amongst the gravel to soften the look.
6. Create a ‘rain garden‘ at the low point of your landscape - dig out a basin about 2ft deep and as long as you can make it. Fill it up with a gravel layer about 2-6″ deep, and then mix the native soil with organic humic compost to help improve drainage. Plant with California natives that typically thrive in seasonal wetlands. Good choices would include ornamental grasses such as Carex or Juncus, bulbs such as Douglas Iris (Iris douglasiana) and Stream Orchid (Epipactis gigantea), and perennials such as Western Columbine (Aquilegia formosa) and Spicebush (Calycanthus occidentalis).
So as Fall turns into Winter and we get our long awaited rains, think about how you can capture the rain in your garden and recycle it.