Rainwater harvesting maximizes collection of the plentiful precipitation that much of the world enjoys. The practice is gaining in popularity, but it’s far from new. In fact, rainwater harvesting enabled some ancient people to survive. It has been practiced for at least 8000 years and in locales from South Asia to the Middle East and Roman Europe.
Rainwater harvesting is simple concept; collect and capture rain as it falls and store it in basins or tanks so that it can be used when demand arises. Rainwater is also gathered in recharge pits that allow it to directly refill groundwater aquifers. For the most part the process is low tech—and low cost.
There are numerous, innovative methods for capturing, storing, and delivering rainwater to farmers’ fields or underground aquifers. Many harvesters simply tailor their systems to the unique environmental conditions at hand.
Many homeowners practice rainwater collection. Roofs, driveways, and other large spaces are used to capture significant volumes of rain which is piped or otherwise diverted into storage containers. Though this water is usually not potable, it can be used for toilets, lawns and gardens, and elsewhere so that drinkable water is conserved.
Rainwater harvesting is also practiced on much larger scales. India is an international leader in the practice, and the nation has launched several projects to capture large volumes of rain and recharge groundwater aquifers much more rapidly then dispersed rainfall could through natural seepage.
Some large-scale collection plans are designed to take advantage of the topographical conditions that produce rainwater runoff. Where rainwater naturally collects in runoff channels, these flows are intercepted with dikes, dams, and other structures that can capture water before it enters the ground or evaporates.