Tamil Nadu

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

For administrative purpose, the State is divided in to 32 Districts, 209 Taluks and 385 Blocks. 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 kms extending from Pulicat Lake to Cape comerin.

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 ground water resource is concerned scarcity is the major problem in hard rock environment while salinity is the problem in sedimentary areas.

 Rainfall:

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 970 mm. Approximately 33 % of this is from the southwest monsoon and 48 % from the northeast monsoon.

The annual rainfall distribution is as follows:

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

 Groundwater Potential:

  Categorization of Blocks  Open

 Sectoral Water Demand and Gap:

Agriculture is a major sector of the State’s economy. Besides meeting the growing demand for food, it is the sector from which the majority of the people earn their livelihood. Of the net area sown only 46% of the area is under irrigation. The rest of the area depends only on rainfall. Productive land is being continually lost on the urban periphery due to urban development and industrialization. Because of the rapid urbanization and high settlement densities, the choice of expanding the irrigated area is reducing rapidly. The next but important constraint is WATER.

Water availability is a pre - requisite for food security and water now is becoming a scarce commodity. The other sectors like industries, hydro - power, domestic, livestock and environment need increasing share of water. The demand from the various sectors as assessed by the Institute of Water Studies, Government of Tamil Nadu is presented in the table below.

 Supply and Demand gap:

The following table depicts the gap between the demand vs availability The challenge is how best this gap could be bridged by reducing the demand or by efficient water management.

 Coverage of Rural Habitations

In Tamil Nadu as on 1.4.2010 there are 93,699 habitations, of which 8,970 habitations are partially covered habitations and 84,729 are fully covered

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

 Water Supply Status in Urban Towns

  Districtwise Water Supply Status in Urban Towns  Open