Ground Water
State of Environment Report of Tripura for the year of 2002

 

Phisiographically, the northeastern region can be subdivided into several units each with distinctive characteristics. Hydrological condition is correlated with geomorphic units, which in turn can provide reliable data on groundwater.

The major geomorphic element observed in Tripura is north-south running parallel hill regions and intervening valleys. The hills are tightly folded anticlines with broad synclinal valleys. These anticline hills form watersheds from which drainage patterns emerge. Geologically, the area is occupied by the folded sedimentary formations ranging in age from lower Tertiary to Recent. Of the various groups of rocks found, Tipam sandstones are considered the main producer aquifer.

 

Extensive hydrological surveys carried out by the Central Groundwater Board in almost all the valleys of Tripura revealed three to four major aquifers within 259m in depth. Such thickness varies from valley to valley but decreases considerably in the synclinal valleys of Kamalpur, Kailashsahar and Dharmanagar. The anticlinal hills intervening the synclinal valley not only act as ground water divides but the sandy formations exposed therein act as recharge zone. Since the recharge area lies in the anticlinal hills, favourable artesian conditions occur whenever good thickness of impermeable clay beds underline and overlie the saturated granular zones. Flowing conditions with auto-flow of 100 to 3000 liters per hour are found mainly in the central part of most of the synclinal valley of Tripura.

 

The worthiness of ground water also varies from valley to valley. While in Agratala valley in the west, they are positively potential, it becomes moderate towards Dharmanagar on the north east.

Records of the technical details from 15 different locations in four districts indicate that tube-wells have been successfully constructed in all the synclinal valleys of Tripura. Large number of shallow tube-wells have been constructed by the State Government at depth of 30m to 60m. In areas fringing the hills (within 2 to 4km), water table generally appear deep and sediments fine, Groundwater structures in such area offered low yields and drawdowns are heavy (Prasad, K.K. 1984, Ground Water Resource of North East India, in Resource Potential of North East India vol. 1: 25-32, Meghalaya Science Society).

The shallow aquifer level are normally located within a depth of 50m below ground level (sometime, it may be at 12-20m depth as in Dharmnagar valley or 5-25m in depth as in Kamalpur valley) and the deeper aquifer occur between the depth ranges of 50m to 200m.

More details of erstwhile three district (South, North and West) groundwater resources are available in “State of Environment Report in Tripura, 1989”.

Recent data in four districts show no decline in groundwater level for 0 to >4m. On the other hand rise in the groundwater level at 0-2m level is noted in 42.11%, at 2-4m level the figure is 57.89% and above 4m level no rise is noted. A total of 19 sampling stations were used to measure the rise and fall of water level during April 1999-August 1999 in Dhalai, North Tripura, South Tripura and West Tripura (Table-23).

 

Table-23: Fluctuation in Water Table : April 1999-August 1999

 

District

No. of Station analysed

Fall of Water Table

0-2m

Percentage

2-4m

Percentage

>4m

Percentage

Dhalai

4

0

0.0

0

0.0

0

0.0

North Tripura

3

0

0.0

0

0.0

0

0.0

South Tripura

2

0

0.0

0

0.0

0

0.0

West Tripura

10

0

0.0

0

0.0

0

0.0

Total Number of Sampling

19

0

0.0

0

0.0

0

0.0

District

No. of Station analysed

Rise of Water Table

0-2m

Percentage

2-4m

Percentage

>4m

Percentage

Dhalai

4

2

50.0

2

50.0

0

0.0

South Tripura

2

1

50.0

1

50.0

0

0.0

North Tripura

3

1

33.3

2

66.7

0

0.0

West Tripura

10

4

40.0

6

60.0

0

0.0

Total Number of Sampling

19

8

42.11

11

57.89

0

0.0

[Source: Central Ground Water Board, Govt. of India]

 

The depth of water level in all the four districts show a typical pattern. The water level becomes highest between the month of August and start declining from January to April.

 Table-24: Depth of Water level (meter), below ground level, mbgl

 

Place

April’99

August’99

November’99

January’2000

Dhalai District

Kamalpur

3.96

1.73

NA

2.29

Manu

6.22

4.41

NA

5.81

North Tipura District

Kailasahar

3.90

0.83

NA

NA

Kanchanpur

NA

NA

NA

5.86

Kumarghat

8.94

7.24

NA

7.85

Panisagar

7.39

3.42

NA

5.04

South Tripura District

Belonia

NA

1.98

NA

NA

Subroom

NA

NA

NA

NA

Udiapur

1.86

1.10

2.30

NA

West Tripura District

Agartala

10.44

8.91

7.14

8.81

Bishalgarh

4.30

3.25

4.11

3.08

Khowai

NA

2.13

NA

4.63

Mohanpur

4.32

0.83

2.04

NA

Narsingarh

7.89

4.14

5.50

5.66

Sonamura

4.35

1.65

2.83

2.16

Teliamura

6.80

1.86

2.92

6.06


 
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