Central Ground Water Board, Ministry of Water Resources, Government of India

Ground Water is a Precious National Resource - Preserve it, Protect it and Don't Pollute it.

State Profile
Ground Water Scenario of Tamil Nadu

Area (Sq.km)	1,30,058
Rainfall (mm)	995
Total Districts / Blocks	30 distt. 384 Blocks

Hydrogeology

Nearly 73% of the total area of the State is occupied by a variety of hard & fissured crystalline rocks like charnockite, gneisses and granites. The depth of open wells varies from 6 to 30mbgl. While the depth of borewells generally varies from 30-100m. The sedimentary formations consist of sand stones, limestones and shales whereas Quaternary sediments in the State represented by Older alluvium and Recent alluvium and coastal sands. In the Cauvery delta of Thanjavur district, the artesian pressure head ranges between 4.5 m to 17 magl with free flow up to 270 m3/hr. The yield of wells in the alluvium varies form 27 to 212 m3/hr. The yield of wells in the fissured formations varies from 7 to 35 m3/hr.

Dynamic Ground Water Resources
Annual Replenishable Ground water Resource	23.07 BCM
Net Annual Ground Water Availability	20.76 BCM
Annual Ground Water Draft	17.65 BCM
Stage of Ground Water Development	85 %
Ground Water Development & Management
Over Exploited	142 Blocks
Critical	33 Blocks
Semi- critical	57 Blocks
Ground Water User Maps	29 districts
Artificial Recharge to Ground Water (AR)	Area identified for AR: 17292 sq km Quantity of Surface Water to be Recharged: 3597 MCM Feasible AR structures: 8612 percolation tanks, 18170 check dams, 5 lakh rain water harvesting structure
Artificial Recharge to Ground Water (AR)	AR schemes completed during VIII Plan: 3 AR schemes completed during IX Plan: 10
Ground Water Quality Problems
Contaminants	Districts affected (in part)
Salinity (EC > 3000 µS/cm at 25 ° C)	Dharmapuri, Pudukkottai, Thoothukkudi, Coimbatore, Dindigul, Ramanathanpuram, Salem, Karur, Namakkal, Perambalor, Thiruvannamalai, Vellore, Villupuram, Cuddalore
Fluoride (>1.5 mg/l)	Coimbatore, Dharmapuri, Dindigul, Erode, Karur, Krishnagiri, Namakkal, Perambalor, Puddukotai, Ramanathanpuram, Salem, Sivaganga, Theni, Thiruvannamalai, Trichurapally, Vellore, Virudhunagar
Chloride (> 1000 mg/l)	Pudukkottai, Thoothukkudi, Ramanathanpuram, Namakkal, Cuddalore, Thirunamalai, Thanjavur, Shivaganga
Iron (>1.0 mg/l)	Namakkal, Salem,
Nitrate (>45 mg/l)	Chennai, Coimbatore, Cuddalore, Dharmapuri, Dindigul, Erode, Kancheepuram, Kanyakumari, Karur, Madurai, Namakkal, Nilgiris, Perambalor, Puddukotai, Ramanathanpuram, Salem, Sivaganga, Theni, Thiruvannamalai,Thanjavur, Tirunelveli, Tiruvallur, Trichi, Tuticorin, Vellore, Villupuram, Virudhunagar

Enactment of Ground Water Bill to regulate and control the development of ground water:

The State Government of Tamil Nadu has passed an Act “Tamil Nadu Ground Water (Development and Management) Act, 2003” on 04.03.2003 which includes provision of Tamil Nadu Ground Water Authority to regulate and control water development in the State of Tamil Nadu.

Inclusion of Roof Top Rain Water Harvesting (RTRWH) in building by laws:
Vide Ordinance No. 4 of 2003 dated July, 2003 laws relating to Municipal Corporations and Municipalities in the State have been amended making it mandatory for all the existing and new buildings to provide RWH facilities.
The State has launched implementation of RWH scheme on massive scale in Government buildings, private houses/Institutions and commercial buildings in urban & rural areas. The State Government has achieved cent percent coverage in roof top RWH.

Central Ground Water Authority

Areas Notified for Regulation of ground water development	NIL
Mass Awareness Programme (as on 31.03.2011)	27
Water Management Training Programme (as on 31.03.2011)	20

CENTRAL GROUND WATER BOARD

Central Ground Water Authority