Rain water runoff is a growing problem in many American cities. The hard surfaces of roads, sidewalks and parking lots interfere with the natural process of rain water absorption, causing the water to puddle and run off into gutters and sewer systems, collecting pollutants along the way. Rain-capture solutions that can be used on public and private properties, called Low Impact Development or LID for short, are often encouraged by cities like Los Angeles, which announced in January, 2010 that they are considering a law requiring the use of rain-capture devices in many buildings and properties.
Porous Paving Materials
In 2006, the city of Philadelphia began installing porous pavements in selected public areas like basketball courts and school yards. The pavement looks like concrete, but it doesn't contain the fillers that make regular concrete impervious to water. When it rains, the porous concrete quickly absorbs the water, filtering it into a gravel bed below the top surface. Perviouspavement.org, a website developed and maintained by the National Ready Mixed Concrete Association, offers tips and advice for mixing porous concrete for contractors and DIY handymen.
Modular Paths, Walkways and Patios
Porous cement isn't the only paving material that can help reduce rain water runoff. The Clemson University Department of Horticulture Extension Service recommends using "permeable paving surfaces" for patios and walkways. The examples offered in their leaflet "Rainwater Runoff: Protecting Your Landscape," include modular paving materials and wood decks, both of which slow the runoff of rain water and allow it to soak into the ground beneath the walkway, path, patio or deck.
Landscaping Solutions to Rainwater Runoff
According to the Clemson Extension Service, landscaping your property can also help slow rainwater runoff. Terraces are especially effective in slowing and capturing rainwater and are an attractive landscape solution for sloping yards. Many homeowners plant rain gardens, which are designed to capture the runoff from downspouts, gutters and driveways. A rain garden located close to the house will capture the runoff from the roof and downspouts, while one located further away can service the entire lawn or the patio.
Downspouts tend to concentrate runoff in one spot, contributing to erosion. Instead of directing the downspout onto the ground, point it into a rain barrel to collect rain water for gardening and other outdoor tasks that require water. There are many specialty rain barrels on the market that include intake filters, runoff valves and hoses that allow you to draw off the water collected in the barrel for watering the garden, washing off garden tools, washing your car or even bathing pets.