1. PROJECT ON RAIN WATER HARVESTING
FOR MANGALDAI TOWN
An initiative on newly elected MLA GURUJYOTI DAS
By Mir Kamaruz Zaman(Er. civil)

2. WHATIS RAINWATER 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.
It 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.

3. 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.

4. 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.

5. SYSTEM OF RAIN WATER HARVESTING
Commonly used system s are constructed of three principal components. They are:-
 Catchment areas:- 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.
 Conveyance system:- It is required to transfer the rainwater collected on the
roof tops 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.

6. METHODS OF RAIN WATER HARVESTING
 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 sub components:-
i) Catchment
ii) Transportation
iii) First flush
iv) Filter

7. Diagrams of rain water harvesting

8. Diagrams of rain water harvesting

9. Diagrams of rain water harvesting

10. Diagrams of rain water harvesting

11. Diagrams of rain water harvesting

12. Diagrams of rain water harvesting

13. IMPORTANCE OF RAIN WATER HARVESTING
1) The gathered rain water can be used for agricultural
purposes. The environment may be helped to get rid of the
tendency to drought.
2) The requirement of water for feeding the live stock can be
met.
3) The ever increasing demand for water can be satisfied.
4) The quantity of the subterranean water can be increased.
5) Wastage of water flowing through drain, gutter, or any water
– course of any type may be stopped.
6) Water-logging on roads and thoroughfares can be checked
and localities can be saved from being inundated.
7) The quantity of water can be raised and soil erosion can be
checked.

14. SUGGESTIONS
For a small town such as Mangaldai we should try to harvest
rain water from roof tops as it is less costly. We should try it
first in:-
i. Government buildings
ii. Offices
iii. Courts
iv. Government bungalows
v. Public buildings
vi. Public toilets
We than check the effectiveness and efficiency of this system
and proceed further for every household in town and try
harvesting the surface runoff also. This will further reduce the
water logging problem of our town and also would solve the
problem of water supply in the town and nearby areas.