Rainwater harvesting is the deposition and accumulation of rainwater for
reuse on-site, rather than allowing it to runoff. Uses include water for
garden, water for livestock, water for irrigation, water for domestic use
with proper treatment, and indoor heating for houses etc. In many places the
water collected is just redirected to a deep pit with percolation. The
harvested water can be used as drinking water as well as for storage and
other purpose like irrigation.Advantages
Rainwater harvesting provides an independent water supply during regional
water restrictions and in developed countries is often used to supplement
the main supply. It provides water when there is a drought, can help
mitigate flooding of low-lying areas, and reduces demand on wells which may
enable ground water levels to be sustained. It also helps in the
availability of potable water as rainwater is substantially free of salinity
and other salts.
The concentration of contaminants is reduced significantly by diverting
the initial flow of run-off water to waste.[1] Improved water quality can
also be obtained by using a floating draw-off mechanism (rather than from
the base of the tank) and by using a series of tanks, with draw from the
last in series. The stored rainwater may need to be analyzed properly before
use in a way appropriate to ensure its safe use.
Quality
The quality of collected rainwater is generally better than that of
surface water. Contamination is always possible by airborne mists and dust,
bird feces, and other debris, so some treatment may be necessary, depending
on how the water will be used
Rainwater harvesting systems can be installed with minimal skills. The
system should be sized to meet the water demand throughout the dry season
since it must be big enough to support daily water consumption.
Specifically, the rainfall capturing area such as a building roof must be
large enough to maintain adequate flow. The water storage tank size should
be large enough to contain the captured water