Department of Science & Technology, Lakshadweep

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FORMATION AND GROWTH OF ISLANDS

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LOCATION, BOUNDARIES, AREA AND POPULATION

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CLIMATE         

 
bulletRain Fall
 
 
bulletTemperature and Humidity
 
 
bulletCloudiness
 
 
bulletWind Speed
 
 
bulletSpecial Weather Phenomena
 
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Natural Calamities  (Storm and Cyclone)

FORMATION AND GROWTH OF ISLANDS

     The islands on these atolls are invariably situated on the eastern reef margin except Bangaram and Cheriyakara which lie in the centre of the lagoon. On Bitra, the island is on the northern edge of the lagoon. The atolls Show various stages of development of the islands, the reefs at Cheriya panniyam, Perumalpar and Suheli represent, the earliest stage while Kalpeni, Kavaratti, Agatti and Kadmat are in intermediate stage and Chetlat and Kiltan are in an advanced or mature stage of  development. The  development and growth of the islands on eastern reef margin has been controlled by a number of factors. The cyclones from the east have piled up coral debris on the eastern reef while the very high waves generated annually during the southwest monsoon have pounded the reef and broken this into coarse and subsequently to fine sediments which was then  transported and deposited on the eastern side behind the coral boulders and pebbles on the eastern reef. A gradual accretion of sediments by this process has led to the growth of the islands. Even the atolls where the islands are not yet fully developed (Suheli, Valiyapanniyam and Bitra) sandy cays occur on the eastern reef margin. In some of the lagoons like Kiltan and Chetlat the islands are growing at a very fast rate and during the next decade the lagoon itself may be filled up with sediments. In such atolls where openings occur in the reef or where the lagoon is too wide for the sand to be transported across its entire width. sand banks usually develop and enlarge towards the centre of the lagoon leading to the formation of the island in the centre such as in Bangaram and Suheli etc.

    The islands do not have any rivers or creeks but some brackish water ponds occur at Bangaram and Minicoy. At Bangaram the pond has been formed during the process of growth of the Islands where the outlet of the bay has been blocked by sand. At Minicoy, a similar pond was being formed at the southern edge but a bund has been constructed and this has created an artificial brackish water pond.

LOCATION, BOUNDARIES, AREA AND POPULATION

     The islands are irregularly scattered in the Arabian Sea between 8" and 12"-30'  north latitude and  between 71" and 74" east longitude. There are in all twenty seven islands and a number of sunken banks, open reefs and sand banks. Only eleven islands are inhabited (including the Bangaram island which is newly inhabited). Other islands are small and exist as satellites of the inhabited islands, which are away from  Kozhikode by  about 200 to 400 kilometers.  

     According to the Survey of India,  the geographical area of Lakshadweep is 32 Sq. Kms. Its area according to the revenue records is only 28.5 Sq. Kms., which represents only the land use area.  The names of the inhabited and uninhabited islands indicating the area are given below.

INHABITED ISLANDS

 No Name Population

Area

in Sq. Km

Total

 

Location

Island

Lagoon

Latitude

Longitude

1

2

3

4

5

6

7

8

9.

10

Minicoy

Kalpeni

Andrott

Agatti

Kavaratti

Amini

Kadmat

Kiltan

Chetlat

Bitra

  9495

  4319

10720

  7072

10113

  7340

  5319

 3664

 2289

  264

 4.80

 2.79

 4.90

 3.84

 4.22

 2.60

 3.20

 2.20

 1.40

 0.10

30.60

25.60

    ..

17.50

  4.96

  1.50

37.50

  1.76

  1.60

45.61

35.40

28.20

  4.90

20.10

  8.66

  4.10

 40.71

  3.96

  3.00

45.71

   816

  1004

  1048.5

  1051

   1035.5

   1107

   1113

   1129

   1141

   1135.5

 

7303

7336

7340

7211

7230

7244

7246

7300

7241

7209.5

 

UNINHABITED ISLANDS

S.No

Name

Area  in Sq. Km

 

Total

 

Location

 

Latitude       Longitude

Island 

lagoon

 

 

 11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

 

Viringili

Cheriyam

Kodithala

Tilakkam (i)

Thilakkam (ii)

Thilakkam (iii)

Pitti (i)

Pitti (ii)

Bangaram

Thinnakara

Parali(i)

Parali (ii)

Parali (iii)

Kalpitti

Suheli Valiya Kara

SuheliCheriya Kara

Pitti (Birds Island)

 

 

 

 

 

 

 

 

 

    2.3

 

    

      

 

 

 

 

 

 

 

 

 

 

125.21

 

 

 

 

 

 

 

 

 

127.51

 

 

The 17 uninhabited islands from S.No. 11 to 27 are located in the close vicinity of the inhabited islands.

REEFS

S.No.

Name

Area  in Sq. Km

Total

 

Location

 

land

lagoon

Latitude       Longitude

 

28

29

30

 

Beliapani

Cheriapani

Perumalpar

 

     ..

     ..

     ..

 

  57.46`       172.59

  83.02

 

  57.46

172.59

  83.02

 

 

1217             7152

1149             7143

117               7159

SUBMERGED SAND BANKS

S.No.

Name

Area  in Sq. Km

Total

 

Location

 

land

lagoon

Latitude       Longitude

31

32

33

34

35

36

Bassas de Pedro

Sesostris

Corahdiv

Amini-Pitti

Elikalpeni

Investigator  Bank

 

     ..

     ..

     ..

     ..

     ..

     ..

2474.33

  388.53

  339.45

  155.09

    95.91

  141.78

2474.33

  388.53

  339.45

  155.09

    95.91

  141.78

1230            7214

1300             7151

1334            7204

1044            7228

117              7359

 833             7325

 

 

CLIMATE

     Lying well within the tropics and  extending to the equatorial belt, these islands have a tropical  humid, warm and generally pleasant climate, becoming more equatorial in the southern islands of the  territory. From the point of view of temperature, the climate is equable and no distinct and well marked seasons are experienced. Southwest monsoon period is the chief rainy season which lasts from late May to early October.

RAIN FALL

Normal and Extremes of Rain Falls

Station No of Years  (Data) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual Highest Annual % of Normal &Years Lowest Annual % of Normal &Years Heaviest in 24 hrs
Amount Date
Minicoy 50 a 43.2 22.3 20.8 51.3 179.6 309.1 238.3 209.3 158.2 179.1 143.3 85.9 1640.4 127 (1902) 64 (1939) 224.9 1965 Dec,8
b 2.6 1.3 1.4 2.9 8.7 17.4 13.9 12.4 10.1 10.6 8.1 4.7 94.1
Amini 50 a 20.6 2.0 4.3 25.4 125.2 380.7 311.9 217.2 149.6 141.1 85.6 40.9 1504.5 169 (1933) 60 (1934) 241.8 1909 Aug,27
b 1.3 0.3 0.3 1.4 5.2 17.3 16.5 12.3 10.2 8.4 5.0 2.2 80.4

  (a) Normal Rain Fall in mm (b) Average no. of Rainy days (days with rain of 2.5 mm or more - based on all available data up to 1965

Frequency of Annual Rainfall

Range in mm No. of Years Range in mm No. of Years

Minicoy (Data 1901 - 1950)

1001 - 1100 1 1601 -1700 11
1101 - 1200 1 1701 - 1800 1
1201 -1300 3 1801 -1900 5
1301 -1400 2 1901 - 2000 3
1401 - 1500 6 2001 - 2100 3
1501 - 1600 6    
Amini (1902 - 1950)
901 - 1000 2 1801 - 1900 1
1001 - 1100 1 1901 - 2000 5
1101 - 1200 4 2001 - 2100 1
1201 - 1300 5 2101 - 2200 0
1301 - 1400 8 2201 - 2300 1
1401 - 1500 4 2301 -2400 0
1501 - 1600 8 2401 - 2500 0
1601 - 1700 4 2501 - 2600 1
1701 - 1800 4    

 

TEMPERATURE & HUMIDITY

Normals of Temperature ad relative Humidity

Month Mean daily max.Temp. Mean daily min.Temp Highest max. ever recorded Lowest min. ever recorded Relative Humidity
oC oC oC Date oC Date 0830o 1730o

Minicoy

January 29.6 22.7 32.8 1948 Jan,19 17.8 1953 Jan,6 79 72
February 29.8 23.5 32.2 1948 Feb,3 17.2 1946 Feb,1 77 72
March 30.5 24.7 32.8 1941 Mar,28 19.4 1955 Mar13 74 72
April 31.1 26.2 35.6 1942 Apr,22 21.1 1951 Apr,18 75 74
May 31.3 26.3 36.7 1932 May,1 21.7 1956 May,15 77 77
June 30.0 25.3 33.9 1935 Jun,5 22.2 1945 Jun,7 80 80
July 29.5 25.1 31.7 1953 Jul,2 21.1 1938 July,4 81 80
August 29.4 25.1 31.7 1934 Aug,16 21.1 1934 Aug,31 81 80
September 29.5 25.1 32.2 1937 Sep,14 21.1 1953 Sep,19 79 79
October 29.6 24.6 33.3 1931 Oct,3 19.4 1945 Oct,22 79 78
November 29.2 23.6 32.2 1947 Nov,24 17.2 1942 Nov,20 79 77
December 29.7 23.3 32.2 1957 Dec,31 18.3 1955 Dec,15 77 74
Annual 29.9 24.6         78 76

Amini

January 31.4 23.9 36.7 1950 Jan,8 18.9 1912 Jan,8 74  
February 32.0 24.9 35.7 1959 Feb,27 19.4 1923 Feb,4 73  
March 32.7 25.7 37.2 1950 Mar,17 20.6 1950 Mar,6 73  
April 33.0 27.1 37.7 1960 Apr,30 20.0 1923 Apr,24 73  
May 32.6 27.3 37.5 1959 May,6 21.7 1941 May,26 75  
June 30.1 25.9 35.9 1958 Jun,9 21.1 1930 June,1 82  
July 29.3 25.4 33.3 1945 Jul,31 21.7 1910 Jul,10 85  
August 29.4 25.5 33.3 1960 Aug,21 22.2 1925 Aug,1 84  
September 29.8 25.5 33.9 1940 Sep,26 21.7 1960 Sep,29 82  
October 30.4 25.2 36.1 1960 Oct,19 20.6 1928 Oct,23 80  
November 31.2 24.7 35.0 1949 Nov,15 18.3 1910 Nov,29 78  
December 31.5 23.9 35.1 1960 Dec,9 18.9 1908 Dec,5 74  
Annual 31.1 25.4         78  

 

CLOUDINESS

Mean Cloud Amount (okta) and Mean Number of days of Lightly/Heavily clouded skies

  

Station Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
Minicoy 0830 a 12 11 12 8 4 1 1 1 4 6 8 11 6.6
b 10 8 9 12 19 25 24 24 18 17 14 10 15.8
c 3.6 3.7 3.7 4.3 5.5 6.8 6.0 6.3 5.5 5.2 4.5 4.0 4.9
1730 a 11 11 12 8 4 1 1 1 4 5 5 9 5.9
b 10 9 11 13 20 26 26 25 18 19 18 13 17.2
c 4.0 4.0 3.7 4.6 6.0 7.1 6.9 6.5 5.8 5.6 5.3 4.4 5.3
Amini 0830 a 15 12 13 12 5 2 2 2 3 4 9 13 7.7
b 9 4 4 6 15 23 23 19 15 15 11 7 12.3
c 2.9 3.1 2.9 3.6 4.9 6.5 6.4 5.9 5.2 5.2 4.3 3.2 4.5
1730

Not available

 (a) Days with sky lightly clouded  (b) Days with sky heavily clouded  (c) Mean cloud amount

 WIND SPEED

Mean Wind Speed (Km.ph) and predominal Wind Direction  

Station Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
Minicoy a 6.4 6.7 6.9 7.5 11.3 17.1 16.3 14.9 13.0 10.2 7.0 6.2 10.3
M N/NE N/NE NW/N NW/N W/NW W/NW W/NW W/NW W/NW W/NW C-W/NW C-NE/N  
E N/NE N/NE NW/N NW/N W/NW W/NW W/NW W/NW W/NW W/NW NW/N NE/N  
Amini a 5.9 8.0 8.6 10.0 13.6 19.7 23.2 22.9 18.4 10.1 5.6 4.9 12.6
M N/NW N/NW N/NW N/NW W/NW SW/W SW/W W/NW W/NW W/NW NW/N N/NE  
E Data not available

 (a) Mean wind speed in Kms. per hour      (M) Predominant direction in the morning   (E)   Predominant direction in the evening  (C) Calm. The next predominant direction is also indicated when calm is mentioned

 SPECIAL WEATHER PHENOMENA

Mean No. of days with Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual

Minicoy

Thunder 1.3 0.9 1.8 4 6 3 1.7 0.5 0.5 1.4 2 0.9 24
Hail 0 0 0 0.2 0 0 0 0 0 0 0 0 0.2
Dust - storm 0 0 0 0 0.6 0 0 0 0 0 0 0 0.6
Squall 0 0 0.1 0.2 0.5 0.7 0.3 0 0.5 0 0.1 0 2
Fog 0 0 0 0 0 0 0 0 0 0 0 0 0
Amini
Thunder 0.5 0.1 0.7 1.3 3 3 0.7 0.2 0.8 3 3 0.7 17
Hail 0 0.1 0 0 0 0 0 0 0 0 0 0 0.1
Dust - storm 0 0 0 0 0 0 0 0 0 0 0 0 0
Squall 0.2 0 0 0.1 0.9 3 4 1.5 1.6 0.8 1.0 0.1 13
Fog 0 0 0 0 0 0 0 0 0 0 0 0 0

 No of days 2 and above are given in whole numbers

  STORMS AND DEPRESSIONS

     A few of the cyclonic depressions and storms, which form in the south Arabian Sea during April and May, affect the weather  over  the  territory. During the post monsoon months of October to December also, a few of such systems originating in the Bay of Bengal and traveling westwards  emerge into the south Arabian sea, and occasionally affect these islands. In association with these, strong winds are  caused  and  heavy  rains occur. The following table gives the number of storms and depressions which affected the region in the above mentioned months during the 80 years ending 1970. During the rest of the months, the territory was not affected by such systems.

Month

Arabian Sea Storms/ Depression

Bay of Bangal Storms/ Depression

April

4

 

May

1

 

October

8

 

November

9

7

December

3

3

Total

25

10

 The cyclonic storms are believed to be responsible for the disposition of coral debris around the islands forming coral beach and the lagoons.

NATURAL CALAMITIES

Storms and Cyclones

Surrounded by the vast ocean, the islands are open to storms and cyclones. One of the earliest natural calamities recorded was the great storm that struck the islands in April, 1847. It commenced in Kalpeni about 8 p.m. on 15th April, passed on to   Androt  and finally  reached Kiltan after devastating  these  two  islands.  All the houses in Kalpeni were damaged and many were entirely washed away. The population of that island prior to the hurricane was reckoned at 1642. Of these, 246 were drowned or washed away by the  storm. One hundred and twelve perished in the ensuing five months from famine or from the diseases engendered by  unwholesome and insufficient food, 376 escaped to the coast, leaving in the island 908, of whom nearly four-fifths were women and children. The plantations in the island were completely destroyed. Out of upwards of  1,05,000  full  grown  coconut trees, the number before the storm, only 768 survived. In Androth, the population before the storm was 2576. Many people perished in the storm and large numbers of the survivors migrated to other islands. Those left in the island numbered only 900. The coconut  trees  were  almost  completely destroyed . 

In 1891, a violent storm burst upon Kavaratti island causing considerable  damage to  coconut trees. Large remissions of rent upon the cowle lands were necessitated during the next few years. The storm did a great deal of damage in Agatti and its attached islets and the Amindivi group of islands. But the damage done by the storm was not so great in these islands as in Kavaratti. 

Kalpeni island was hit by  a  severe  cyclone on Ist December, 1922. The waves washed completely over the narrow northern end and the sea poured across the island into the lagoon. The people in the northern part of the island had to flee for safety and all rushed to the mosque to pray. Fortunately the  storm  subsided without doing any serious damage beyond blowing down a few trees. The cyclone was scarcely felt in any other island except Suheli and to a slight extent Androth. 

Another major storm which hit the islands occurred in 1941. Kavaratti was the  island most  affected by this storm. In 1963, a cyclone of mild intensity struck  Androth island and 540 coconut trees were uprooted.  The  major calamity in recent times was the storm that hit the territory in December, 1965 causing considerable damage in Androth and Kalpeni islands. About 11,500 coconut trees were uprooted in Androth and about 9,500 trees in Kalpeni. Though the storm was felt in Kavaratti, Agatti and Kiltan, it was not so vehement in these islands. Government sanctioned a grant of about Rs.  14,000 in  kind  towards relief to the victims, in addition to a loan of nearly Rs. 31/2  lakhs.

        [Home][About us][Scientific policy1958][S&T policy 1983][S&T policy 2003][Related sites][General][Ecosystem][Major projects][LIWAMP][LCRMN][Studies ][FAQ][Feed back][Flora & fauna][Birds][Corals][Flora][Fauna][Marine fauna][Photo gallery][Contact us]

This site was last updated 10/03/06