WATER HARVESTING IN ARID AND SEMI-ARID REGIONS

Abstract

Water harvesting, also called rainwater harvesting, is a technique of developing surface water resources to augment the quantity and quality of water available to the people in arid and semi-arid regions where other water sources are not readily available or too costly to develop and use. A waterharvesting system consists of facilities for collecting and storing rainfall and the resulting surface runoff until the water is used for livestock, small-scale agricultural production, or domestic uses. A distribution facility can also be required unless the collected water is immediately concentrated in the soil profile to grow plants. For example, a distribution facility is needed when the stored water is used to irrigate an agricultural crop or provide water to households.Water harvesting is potentially applicable in almost any area receiving at least 100 millimeters (mm) of annual rainfall (National Academy of Science 1974). Larger volumes of water can be stored on sites where the annual rainfall is 250 mm or more and an adequate storage facility is available.