Thinking Outside the House: Draught-proof Gardens
Household uses of water account for only 1 to 8 percent of the fresh water consumed in the United States, but unlike commercial and agricultural use, you can directly control how much water you use in your home. Inside your house, you can fix leaks, install water efficient appliances, and modify your personal habits to save water. But because three-fourths of the water used in homes goes to lawns and gardens, your greatest opportunities to save water may be outside your house.
Thoughtful management outdoors can also help protect water quality and alleviate pressure on municipal wastewater systems. When it rains, water rushes off roofs, paved driveways, and sidewalks. In urban and suburban areas, it flows into storm water drains where it is carried directly into nearby bodies of water or into treatment facilities that can be overwhelmed by the sudden inundation. Such runoff carries with it a host of chemicals that pollute local waterways. Finding ways to hold water on your property allows it to follow its natural path into the groundwater by soaking into the soil (see sidebar) and back into the atmosphere through evaporation. In arid areas, stored water can be a source of moisture to sustain plants through dry months.
Many cities and states have water conservation programs and may offer financial incentives for conservation efforts. Check with your local water department to see what they have to offer in the way of water conservation support. With a little investigation, you will likely find that conserving water in your yard isn't burdensome. It may even bring tangible benefits like a more attractive yard, lower water bills, and a cooler house. Here are a few ideas to help get you started.
The best way to conserve water is to rip out your lawn. There are over 30 million acres of grass lawn in the United States, and each 25-by-40 foot section requires 10,000 gallons of water a summer. Some people let their lawns go dormant (brown) in dry months. But you could “go native” and join the growing movement known as xeriscaping. Xeriscape does not mean zero-scape, the use of rocks and pebbles in lieu of lawns. Xeriscaping is the creative use of native plants that are beautiful, drought-tolerant, and sustainable. Since native plants have had centuries to adapt to local weather patterns, by definition they rarely need extra water once they've become established.
The key to successful xeriscaping is plenty of research and planning. Start by walking around your lawn at various times of day to determine when the sun hits each area. Think about how you want to use your space, and plan out paths and clearings accordingly. Then begin identifying plants native to your region and whose growing needs match the conditions in your lawn. Your library likely has books to advise you on xeriscaping, but your best resources can be found at some local nurseries and at native plant societies. These groups are a wealth of useful information about the plants of your region and the art of xeriscaping.
Native plants will require some extra water to insure that they are successfully established the first year of planting, but should not require additional watering after that. Your new xeriscaped garden will attract birds, butterflies, and a host of other critters—and the envy of your neighbors.
Before there were centralized municipal water systems, people relied on catching rainwater for their household and landscaping needs. Today, people from Texas to India are turning again to rainwater collection as a cost-effective source of clean water. The appeal of rainwater collection lies in its simplicity: catching rain during wet periods and storing it for use in dry seasons. Rainwater collection or catchment systems can be complicated affairs with screens, filters, and large underground tanks or cisterns, or they can be as simple as a garbage can placed under the downspout of a roof-—if you intend to use rainwater for drinking, you will need a filtration system. A rainwater harvesting system includes:
- a catchment area, usually a roof;
- a method for conveying water into a storage unit, typically gutters and downspouts;
- a rain barrel, cistern, or tank that can hold between 50 and 5000 gallons, depending on the size of the catchment area;
- some form of covering to keep large items, like leaves and twigs, out of the barrel or tank;
- a system to deliver stored water to where it is needed. Most rain barrels have spigots you can use to fill a watering can or to attach a hose.
Rethink your driveway and roof
Roofs, driveways, and sidewalks are important players in the urban water cycle. Water that runs off of these hard surfaces does not have the opportunity to soak back into the earth.
One way to reduce the runoff from your property is to build a permeable driveway. One inch of rainfall on the typical home's driveway produces approximately 900 gallons of runoff.
The easiest way to make your driveway permeable to water is to not pave it in the first place. If you are thinking of paving a driveway, consider using gravel, crushed seashells, or woodchips instead.
If you must have a harder surface, there are a number of options for a permeable driveway. You can install widely spaced concrete slabs or bricks and fill the gaps with sand or grass. There are also paving blocks that look like ordinary cobblestones or bricks, but have channels that funnel water in between each block.
To reduce the runoff from your roof, you might consider replacing your conventional roof with a sod roof, also called an ecoroof. Native plants and grasses planted in two to six inches of dirt on your roof require little or no maintenance and a specially designed waterproof lining prevents leaks. The trend toward ecoroofs is increasingly popular in major cities, and has become a design feature of many municipal buildings. Private residences can also install ecoroofs. Ecoroofs will:
- absorb and evaporate between 10 and 100 percent of the precipitation that falls on them;
- moderate temperatures and, in the process help to reduce smog levels, because the dark surfaces typically found in roofing absorb and radiate heat, creating urban heat islands that raise temperatures 6 to 10 degrees;
- last twice as long as a conventional roof;
- increase vegetation and animal habitat in urban areas;
- insulate against cold, heat, and noise.
The best time to install an ecoroof is when you are building a new structure or replacing an existing roof. It is helpful to enlist the aid of a professional when installing an ecoroof, but with thorough study and planning you can do it yourself.
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