28 July 2008

Rain, rain...

In the early 90's, a small group of people in Los Angeles tried to convince their government that there was a sustainable solution to the city's water crisis.

Rainwater.

Since LA is located in a desert, much of the water has to be trucked in from out of state. It's the reason why the Colorado River no longer reaches the Pacific Ocean. The city is constantly thirsty, yet, in the wet season, also constantly flooded. Most of the city is covered in non-permeable surfaces like asphalt and macadam, making it a disaster area when any significant amount of rain falls on the city.

Even so, public officials laughed at the idea of rainwater catchment systems in LA. They couldn't see the benefits.

Several years later, non-profit organization TreePeople created a 100% effective catchment system for a typical LA single-family home. It had two cisterns for water storage, a grated driveway and drywell to catch runoff, and landscaping that retained rainwater. In a demonstration in front of public officials where a firehose rained upon the house, no water gushed out into the street. Instead it was collected and stored in the cisterns or allowed to percolate back into the aquifer.

Officials were amazed. They immediately asked TreePeople to modify larger buildings. This led the organization to create rainwater catchment systems for two public elementary schools. They tore up the asphalt around the schools (the school system had begun to pave the entire property to save on landscape maintenance costs) and created more green space, dug swales to let the rainwater pool and sink into the ground, and installed huge underground cisterns, allowing the schools to use almost exclusively rainwater.

Now, TreePeople is working with the LA Department of Public Works to change the Sun Valley area in the San Fernando Valley, applying their methods to an even larger scale to reduce runoff and prevent millions of gallons from being imported into the area.

So, why hasn't this caught elsewhere?

Rainwater catchment isn't new. It's been around in India and China for thousands of years, with each home having their own catchment system to help replenish their wells. In India, man-made ponds collect rainwater that is then used for irrigation, turning once barren soil into lush, fertile farmland.

Unfortunately, in the United States, only the more arid areas, such as California and Texas, have even considered rainwater catchment systems to help avert a drought crisis. In some states, such as Michigan, rainwater harvesting is illegal.

To me, the solution to the water shortages, current and future, seems obvious. Instead of carting millions of gallons of water all across the country, the smarter option would be to collect what precipitation already falls on the ground. Even propping a trashcan covered in a window screen against your downspout would save on irrigation costs for your lawn.

Rainwater harvesting helps offsets your water bills, but also reduces environmental impact. Storm runoff floods streets and lawns, collecting all sorts of nasty chemicals from your lawn and driveway before heading down the sewer and into a nearby stream. Rainwater catchment slows down and can even stop the runoff process. Here are some very simple ways you can reduce stormwater runoff at home:

1. Rinse out an old trashcan, barrel, or container from the garage, place a screen over it (so birds and small animals don't get it) and secure the screen around the container. Place the container below your downspout. Scoop out rainwater as needed to water your plants.

2. If you're doing some landscaping, think about what you're planting. Use native, drought-tolerant plants that require less water and are more beneficial to the area. Hardy trees, shrubs, and grasses are great additions to your landscaping.

3. If you're doing some more intensive re-landscaping, think about creating some swales or depressed areas. Swales can be sunken areas in your backyard filled with mulch and yard trimmings that help absorb rainwater. In your front yard you can lower the area right before your sidewalk and plant with mulch and grasses to help keep rainwater from flooding onto the sidewalk and street. Think about how your current landscaping works and if it is catchment-friendly.

4. If you're putting in a new driveway, sidewalk, or pathway around your home, consider using permeable surfaces. This way the rain can soak into them and percolate into the ground instead of rushing off the surface.

Using rainwater reduces reliance on the public system, wells, and money spent for non-potable water use. It is a powerful and relatively untapped resource in the United States. Citizens can show their government that it is a viable option and can help avert any future water crisis.

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