Showing posts with label collection. Show all posts
Showing posts with label collection. Show all posts

July 22, 2009

Harvesting Rain

Though we usually tune out the pitter-patter of rain on the roof, water flowing down the gutters and into the storm drain is a valuable resource. We not only depend on water, we also pay for it. So, why not put that rainwater to use?

Nearly any homeowner can collect rainwater, since the roof and gutters do most of the work. Furthermore, they can harvest huge volumes. An inch of rain, falling on a 2,000-square-foot roof, produces 1,200 (4,500 litres) gallons of runoff, which is enough to supply a family of four for about two weeks.

Using rainwater has obvious budgetary benefits, but there are reasons to do it besides putting a dent in the water bill. For those facing water shortages, harvesting rain can help keep the lawn green, or even provide water for indoor use. However, water to be used indoors, whether for washing or for drinking, must be thoroughly treated.

There are a slew of benefits that come with the purity of rainwater. Plants prefer it, especially if tap water has been treated with softening salts, which dampen plant growth. The lack of minerals in rainwater make it more effective for washing hair or doing dishes. Furthermore, reducing or eliminating mineral deposits in pipes and water heaters can extend their life, requiring less maintenance and associated costs.

Collecting rainwater also reduces pollution-causing runoff, and if it is collected and used without the aid of pumps or other powered equipment, provides a carbon-neutral water source.

The simplest form of rainwater collection is also the most affordable: a rain barrel positioned under a gutter’s downspout. The barrel is typically fitted with a spigot at its base to fill a watering can or attach a soaker hose (which bleeds out water all along its length, providing effortless drip irrigation), and a filter or screen at its top to prevent a buildup of leaves and other debris.

With a little work a barrel’s capacity can be increased. When the barrel is full, runoff is directed through a spout near the top of the barrel called an overflow port. This spout can be made to flow into another barrel, increasing capacity.

However many barrels are connected, though, a downspout must be attached to the last overflow port. This attachment directs overflow away from the building, preventing water from pooling around the barrel’s base.

With a few simple materials and a bit of ingenuity, a rain barrel can be built at home. There are countless tutorials online on how to do this. Check out Google for links. Though buying a premade barrel is easier, it is also more expensive.

A world apart from rain barrels are the more complex setups that provide water for indoor use. These systems use cisterns that hold thousands of gallons, and have treatment systems to remove sediment and harmful organisms from collected water.

There are several methods for treatment, but one of the most common is a combination of filters and ultraviolet light. These very fine filters remove particles, some organisms, and can even absorb bad odors and tastes. After filtration, an ultraviolet light shines on the water as it flows through a clear quartz tube, killing any remaining pathogens.

The prices for these systems can vary widely depending on your needs, and are not do-it-yourself projects. Above-ground is generally cheaper. Unlike rain barrels, either option (on a large enough scale) can make a household totally water-independent.

[Extract from emagazine]


In next month's Arunachala Grace Newsletter there will be a narrative on rainwater harvesting concepts utilised in Tamil Nadu. If you wish to receive a copy of this free bi-monthly Newsletter, check out the subscription facility at the left hand column of this page.