Rain water harvesting
> The harvesting of rain water simply involves the
collection of water from surfaces on which rain falls,
and subsequently storing this water for later use.
Normally water is collected from the roofs of buildings
and stored in rainwater tanks.
At is the accumulation and deposition of rainwater for
reuse on site.
> The harvested water can also be used as drinking water,
long term storage and for other purposes such as
ground water recharge.
ADVANTAGES
The technology is simple and easy to install.
Local people can be easily trained to implement such technology
and construction material is easily available.
It has low maintenance cost and running cost.
Water collected from roof catchments usually is of acceptable
quality for domestic purpose.
Rain water can be a continuous source of water supply for both the
rural and the poor.
Depending upon the conditions both water collection capacity and
storage capacity can be increased as needed within the available
catchment area.
DISADVANTAGES
Disadvantages are mainly due to the limited supply and
uncertainty of rainfall.
SUITABILITY
The augmentation of municipal water supplies with harvested
rainwater is suited to both urban and rural areas. The
construction of cement jars or provision of gutters does not
require very high skilled manpower.
SYSTEM OF RAIN WATER HARVESTING
Commonly used system s are constructed of three principal components. They are:-
This include roof catchment where rainwater is collected in
simple vessels at the edge Of the roof and land surface catchment which involves
improving runoff capacity of land surface through various techniques including
collection of runoff with drain pipes and storage of collected water. Collection
Devices:- Storage tanks for collecting rainwater harvested using guttering may be either
above or below the ground. Precautions required in the use of storage tanks include
provision of an adequate enclosure to minimize contamination from human. animal or
other environmental contaminants. Convevgoce It is required to transfer the rainwater
collected on the rooftops to the storage tanks. This is usually accomplished by making
connections to one or more down pipes connected to the rooftop gutter.
Consideration should be given to the fact that when it first rains dirt and debries from the
rooftop and gutters will be washed into the down pipe. Thus, the relatively clean water will
only be available some time later in the storm.
METHODS OF RAIN WATER HARVESI
Surface runoff harvesting:- In urban area rainwater flows away as surface runoff.
This runoff could be caught and used for recharging aquifers by adopting
appropriate methods.
Roof top rain water harvesting:- in this system the rain water is collected from the
roofs and it can either be stored in a tank or can be diverted to artificial recharge
system. This is less expensive and very effective and if implemented properly
helps in augmenting the ground water level of the area. This system mainly
constitutes of following
water har.Yhting
