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.
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.
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.
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.
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
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.
details of erstwhile three district (South, North and West) groundwater
resources are available in “State of Environment Report in Tripura, 1989”.
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).
in Water Table : April 1999-August 1999
Central Ground Water Board, Govt. of India]
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.
of Water level (meter), below ground level, mbgl