INTRODUCTION
The
term ‘rainwater harvesting’ appears to have originated from the word
‘harvesting’, used to cover all agricultural activities involving cutting,
reaping, picking and gathering of grain of value from any fully-grown crop.
Rainwater harvesting may be defined as any human activity involving collection
and storage of rainwater in some natural or artificial container either for
immediate use or use before the onset of the next monsoon.
Rainwater
harvesting is the capture, diversion, and storage of rainwater for a number of
different purposes including landscape irrigation, drinking and domestic use,
aquifer recharge, and storm water abatement. In a residential or small-scale
application, rainwater harvesting can be as simple as channeling rain running
off an unguttered roof to a planted landscape area via contoured landscape. To
prevent erosion on sloped surfaces, a bermed concave holding area own slope can
store water for direct use by turf grass or plants (Waterfall, 1998).
Archeological evidence
attests to the capture of rainwater as far back as 4,000 years ago, and the
concept of rainwater harvesting in China may date back 6,000 years. Ruins of
cisterns built as early as 2000 B.C. for storing runoff from hillsides for
agricultural and domestic purposes are still standing in Israel (Gould and
Nissen-Petersen, 1999).
Rainwater collected from the
roofs of houses, tents and local institutions can make an important
contribution to the availability of drinking water. Water collected from the
ground, sometimes from areas which are especially prepared for this purpose, is
called Storm water harvesting. Rainwater harvesting is the process of augmenting the natural filtration
of rainwater in to the underground formation by some artificial methods. Or
simply "Conscious collection and storage of rainwater to cater the demands
of water, for drinking, domestic purpose & irrigation is termed as
Rainwater Harvesting."
Roof rainwater can be of good
quality and may not require treatment before consumption. Although some rooftop
materials may produce rainwater that is harmful to human health, it can be
useful in flushing toilets, washing clothes, watering the garden and washing
cars; these uses alone halve the amount of water used by a typical home.
Household rainfall catchment systems are appropriate in areas with an average
rainfall greater than 200 mm (7.9 in) per year, and no other accessible
water sources (Skinner and Cotton, 1992).
As the water
crisis continues to become severe, there is a dire need of reform in water
management system and revival of traditional systems. Scientific and technological
studies need to be carried out to assess present status so as to suggest
suitable mitigative measures for the revival to traditional system/wisdom.
Revival process should necessarily be backed by people's initiative and active
public participation.