Rainwater harvesting is the collection and storage of rainwater. It is used to provide drinking water, water for livestock, and water for irrigation or to refill aquifers in a process called groundwater recharge.
Rainwater collected from clean surfaces, such as roofs or from specially prepared areas of ground, can provide an important complementary water source. Indeed under some circumstances, rainwater may prove to be the only available or economical source of water.
Rainwater collection systems can be simple to construct using cheap local materials, and are potentially successful in most habitable locations.
A simple rainwater harvesting system.
Source: Image courtesy of WEDC. © Rod Shaw
( click to enlarge )
Sizing of the storage within the system is of essential importance. Generally speaking, the size of the storage tank should be big enough to meet the daily water requirement throughout the dry season.
Rainwater harvesting to provide drinking water for animals is practiced throughout the Kunene River basin using "chimpacas" (rainwater storage facilities dug by the local population). These are generally relatively large, hand-dug depressions in which rainwater is stored and which subsequently serve as a water source well into the dry season. As the chimpacas are open ponds, they are highly contaminated with bacteria, although investigations have shown that they serve as drinking water sources for 25 % of the population of the Kunene Province (World Food Programme 2005).
Rainwater harvesting is seen as having significant potential for livestock watering in the Lower Kunene and its further exploration has been recommended (Kunene Region- Communal Cattle and Small Stock Zone – Baseline Livelihood Assessment, April 2009).
More information on rainwater harvesting can be found here.
