

Objectives The water available in this tiny islands is saline . The main objective to provide safe drinking water to the inhabitants of Lakshadweep islands.
Status:The availability of fresh
water is limited.
Therefore combined System consisting of Ground water,
Rainwater harvesting and R.O. Desalination is adopted in these islands.
a) Total requirement per
day (considering 55lpcd) 33,32,725liters
b) Quantity supplied per
day
3,03,550 Liters
c)
Deficit per day
30,29,175 Liters
Ground
water :
Lakshadweep Administration prepared water supply scheme to this
Territory for the extraction of ground water through collector
wells. The scheme envisages extraction of
ground water through radial perforated pipes of 5m length located at specified
shallow depth. The ground water flows under gravity through these pipes and
collect in a collector well. This checks excessive draw in two ways.
I.The extraction is not from a particular
point, but extraction along with the length of radial pipes so that the amount
of draw gets distributed for a diameter of 16 metres.
II. In
no case the water below a predecided level will be collected since the inflow
is only through perforated pipe. The bottom of the wells is sealed with
concrete; as such it does not allow seepage of water from the bottom.
Method followed:-
There are 4 to 6
such collector wells in each island. These wells are selected at sites where
quality of water is good and thickness of sweet water lens is maximum. Water
from these collector wells is pumped intermittently to the collection sump.
Extraction of water from each well is done for half an hour and then stopped
for an interval of 2 ½ hours to allow time to interface to subside. After
chlorination, the water is pumped from the collection sump to the overhead
water tanks. The water is supplied through standposts on the streets. ie street
taps
A
Central Team headed by Shri Mohammed Inamul Haque , Adviser, Technology
Mission, Department of Rural Development, Government of India along with
experts from Central Ground Water Board, Central Salt and Marine Chemical
Research Institute, Bhavanagar, National Environmental Engineering Research
Institute and Center, for Earth Science Studies visited the islands in June
1988 came to the conclusion that no single system of approach to provide water
supply to these islands would be sufficient due to typical geological and hydro
geological nature of these islands. This team of experts was of the opinion
that the right approach to solve the problem of drinking water in these islands
can consists of three elements as follows.
a) Use
the ground water to the extent available, the exact quantity which can be
extracted without danger of salinity to be determined by a detailed island wise
study to be conducted by Center for Earth Science Studies.
b) Wherever the ground water is not
adequate to provide water to the entire population, this has to be supplemented
by Desalination of brackish water through Reverse Osmosis Plants.
c) Recognising the value of the water as a scarce resource on
the islands, it was decided to optimize the availability of the resource by
encouraging rain water harvesting so that atleast some of the water which
otherwise is wasted could be utilized for part of the year.
Water
received from the above sources is distributed through a common network of
underground pipes and public stand posts. The system is managed by local
Panchayaths.
Rain Water Harvesting:
The Rain Water
collection is the most suitable and adoptable method to make up the short
falls. Therefore, we have started collection of rain water utilizing the roof
tops of the buildings as catchments area. Individual storage tanks of various
capacities ranging from 5 to 10 thousand liters, in some cases even up to 50
thousand liters, are constructed attached to each Government quarters, non
residential buildings and private houses. The water collected in the eve gutter
from the roof tops is made to flow to the collection tank through a filter so
that suspended particles are got removed. Then the water is chlorinated using
bleaching powder. Since the collection tanks are attached to each house, it is
easy to maintain because the householder can take up normal maintenance.
Operation related to the pumping and distribution of water is entrusted with
the respective Village (Dweep) panchayats in respect of water collected in
community RWT in Hospitals, Schools etc.
By utilizing the roof tops of public buildings, such as schools, we
have also introduced Community Rain Water Harvesting System. Here also, the
water is got filtered chlorinated using bleaching powder in a centralized
filter and then pumped to the over head tanks for distribution along with the
water collected from other sources such as ground water, desalination plants
etc.
Merits:
1.There are no environmental hazards and actually it is environment
friendly.
2.Reduces pumping which helps to dilute the salinity of ground
water.
3.No power consumption or operational cost is involvedin respect of
individual RWTs.
4.Seawater
intrusion in to the land is arrested.
5.Construction Technology and Cost involved is less compared to other systems.
Statistics:
There are 2Nos
Community Rain water harvesting system one each at Kavaratti and at Minicoy. In
addition to this there is individual RWH tanks.As on today we have created
infrastructure for Rain Water Harvesting to an extent of 11.092 Million Liters.
Rain water Tanks
constructed
S.No Islands Govt.Buildings Private
Houses Total
1 Agatti 56 278 334
2 Kavaratti 300
90 390
3 Andrott 8
13
21
4 Kalpeni 51
46
97
5 Minicoy 206
146
352
6 Amini 60
80 140
7 Kadmat 24
50 74
8 Kiltan 8
167 175
9 Chetlat 24
107 131
10 Bitra 12
60 72
Total 744 1035 1786
Ground water
Quality monitoring There are 9 Nos Water Quality Testing Laboratory
installed one in each island . The Lab is monitoring quality of water
from selected wells in each island and the local Public Health authorities
are kept informed. Salinity is the main
hazard.
R.O.Plants:- Ten Brackish water
R.O Desalination plants are installed at different islands.
Distribution System:
Number of Street taps Provided is as follows
|
S.No |
Islands |
Street
Taps |
|
1 |
Agatti |
140 |
|
2 |
Kavaratti |
140 |
|
3 |
Andrott |
125 |
|
4 |
Kalpeni |
198 |
|
5 |
Minicoy |
235 |
|
6 |
Amini |
63 |
|
7 |
Kadmat |
73 |
|
8 |
Kiltan |
339 |
|
9 |
Chetlat |
127 |
|
10 |
Bitra |
Nil |
|
Total |
|
1440 |
It is proposed to provide Sea water R.O.desalination plants of required capacity in each islands to meet the short fall.