Rain Water Harvesting

We who live in cities and towns, and we who eat food grown on industrial farms, depend on imported water for daily survival. Our water and the water that grows our food travels hundreds of miles to reach us. It is powered by mountain-leveling coal, mega-dam hydro-power, and deadly nuclear power. The infrastructures that bring us this water costs billions of dollars in public tax money and household utility bills.

Harvesting rainwater can reduce our need and demand for water transport systems that threaten the health of the water cycle and our local environments. Ironically, water use is often highest in the places where rain falls the least. But whether you live in the tropics or an arid desert we almost all depend on problematic water infrastructures.

Rainwater harvesting is one strategy in the greater scheme of reducing domestic water use. By harvesting rainwater, we can be led to dozens of other practices that bring us into greater sustainability. Growing plants that shade and insulate windows reduces energy use; increasing home food production reduces demand for wasteful water use in industrial fields. Above all, rainwater harvesting increases quality of life: ours, and that of life worldwide.

In arid climates and places with salty irrigation water rainwater flushes salts and chemicals out, allowing for long-term health and soil vitality.

On any house lot, there are three potential sources for harvesting the rain: direct rainfall, street harvesting, and roof harvesting.

The easiest rainwater source is that which falls on the yard. Proper placement of plants, trees, and water sources can turn the site into a water efficient system. Shape the surface of the soil to slow down runoff, raise paths and patios, and sink all planting areas to capture the flow. Choose plants, primarily natives, that can absorb and hold water in their root systems, or pass it down to the water table. This way, rainwater doesn't run off into the street, where it would be swept away with motor oil, into the sewer system or discharged directly into a local waterway.

The second source of rainwater is the street. Streets aren't flat; they are typically graded so that water flows to the curb, down the block to a gutter, into the storm drain. In cities like San Francisco and Portland, storm drains are connected to the sewer treatment plant, and heavy rains cause the sewer plant to overflow raw and partially treated sewer into the bay or river. Other cities connect storm drains to underground creeks, and the polluted water runs straight into the bay or nearby river. By cutting curbs and digging sunken basins into the "right-of way" or "parking strip" area of the sidewalk, you can turn street rainwater from a problem to a resource. Diverted rain that falls on streets can nourish plants, protect creeks, and contribute to cleaner cities.

The third source of rainwater is the roof. Even in areas with low rainfall there is an enormous potential for harvesting rainwater. For example, the roof a 1,000 square foot house can collect around 600 gallons per ONE inch of rain! In an average year with 12 inches of rain that small roof could collect 7,200 gallons.

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