SBA Green Team Tip of the Week (5/4/09)

Who says we get too much rain?

Rainwater harvesting is the accumulation and storage of rainwater. Traditionally, rainwater harvesting has been practiced most in areas where water exists in plenty, and that is definitely the case here in Oregon. The average 1000 square foot home in Oregon “sheds” approximately 22,500 gallons of rain water per year. Rooftop rainwater harvesting systems such as rain barrels (generally 55 gallons) or totes (275 to 325 gallons) are relatively easy and inexpensive to install. Just look on Craig’s List to find many types of rain collection systems and equipment for sale.

The City of Portland has a Clean River Rewards website that outlines how to build a rain barrel system as well as other information on how to make your impact on the watershed more green and sustainable. http://www.portlandonline.com/BES/index.cfm?c=41976

Rainwater harvesting in urban areas has manifold reasons:

• To provide supplemental water for the city's requirement, it increases soil moisture levels for urban greenery
• To increase the ground water table through artificial recharge
• To mitigate urban flooding and to improve the quality of groundwater
• To decrease the use of potable water you pay for to rain water you get for free

In urban areas of the developed world, at a household level, harvested rainwater can be used for flushing toilets and washing laundry. Indeed in hard water areas it is superior to mains water for this. It can also be used for showering or bathing. As rainwater may be contaminated, it is often not considered suitable for drinking without treatment. However, there are many examples of rainwater being used for all purposes — including drinking — following suitable treatment.

• In New Zealand, many houses away from the larger towns and cities routinely rely on rainwater collected from roofs as the only source of water for all household activities.
• Currently in China and Brazil, rooftop rainwater harvesting is being practiced for providing drinking water, domestic water, water for livestock, water for small irrigation and a way to replenish ground water levels.
• In Bermuda, the law requires all new construction to include rainwater harvesting adequate for the residents. The U.S. Virgin Islands have a similar law.
• In Indus Valley Civilization, Elephanta Caves and Kanheri Caves in Mumbai rainwater harvesting alone has been used to supply in their water requirements.
• In Senegal/Guinea-Bissau, the houses of the Diola-people are frequently equipped with home brew rainwater harvesters made from local, organic material.
• In the United Kingdom water is collected in domestic gardens to collect rainwater which is then used to water the garden.

HOWEVER:

• In Colorado, where water is more scarce, water rights laws severely restrict rainwater harvesting -- a property owner who captures rainwater is effectively stealing it from those who have rights to take water from the watershed.

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