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Monday , 29th November 2021
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Salient Details of Tamil Nadu State:

Tamil Nadu

Tamil Nadu state has a geographical area of 1,30,058 and is situated between North Latitudes 080 00’ and 13o30’ and East Longitudes 76o15’ and 80o 18’. The State is bounded by the Bay of Bengal in the east, the Indian Ocean in the south, the Western Ghats in the west and the States of Karnataka and Andhra Pradesh in the north.

For administrative purpose, the State is divided into 32 Districts, 209 Taluks, and 1139 Firkas. The State has 10Corporations, 150 Municipalities, 559 Town Panchayats, 12,620 Panchayat Villages and 93,699 Habitations

Physiographically, Tamil Nadu State is divided into Four units viz.,

  • Coastal Plains.
  • Eastern Ghats.
  • Central Plateau.
  • Western Ghats.

The coastal Plains stretch over a distance of about 998 km extending from Pulicat Lake to Cape comer in.

Tamil Nadu is predominantly a shield area with 73% of the area covered under hard crystalline formations while the remaining 27% comprises of unconsolidated sedimentary formations. As far as groundwater resource is concerned scarcity is the major problem in hard rock environment while salinity is the problem in sedimentary areas.


Tamil Nadu is a state with limited water resources and the rainfall in the state is seasonal. The annual average rainfall in the state is 960 mm. Approximately 33 % of this is from the southwest monsoon and 48 % from the northeast monsoon.

The annual rainfall distribution is as follows:

Season Month Average Rainfall mm Percentage
Winter rains Jan – Feb 47 4.82 %
Summer rains May 138 14.12 %
Southwest monsoon Jun – Sept 322 32.96 %
Northeast monsoon Oct - Dec 470-970 48.10 %

Surface Water Potential:

The total surface water potential of the river basins of Tamil Nadu is assessed as 24160 MCM (853 TMC).

The details of the break up of the potential are as under:

  • 39000 tanks with a storage capacity: 347 TMC.
  • 79 reservoirs with a storage capacity: 243 TMC.
  • Contribution from the other States: 261 TMC.
  • Other Storages: 2 TMC.

The average Runoff (surplus flow) to the sea from the 17 Basins of Tamil Nadu State is computed as 177.12 TMC.

Groundwater Potential:

Categorisation of Firkas No of Firkas
Over-Exploited (>100%) 1139
Critical (90-100%) 105
Semi-critical (70-90%) 212
Safe (<70%) 429
Saline Blocks 35
Total 1139

Coverage of Rural Habitations - As on 1.4.2018

In Tamil Nadu as on 1.4.2018 there are 1,00,069 habitations, of which 4,462 habitations are partially covered habitations and 95,438 are fully covered

Rural Habitations are covered through Individual Power Pump Schemes and Combined Water Supply Schemes

Water Supply Status in Urban Towns

Civic status Good Average Poor Total
Corporations (excluding Chennai) 8 3 - 11
Municipalities 63 60 1 124
Town Panchayats (Erstwhile RTP &UTP) 480 41 2 528
Total 551 104 3 663

Districtwise Water Supply Status in Urban Towns Open