ENVIS

ENVIS
Newsletter
on State of Environment
Supported by Ministry of Environment and Forests, Government of India

Mar 2007 A quarterly issue Vol. 4 No.1

Water Resources of Tamil Nadu

“Water is probably the only natural resource to touch all aspects of human
civilization - from agricultural and industrial development to cultural and religious
values embedded in society.”

- Koichiro Matsuura, Director General, UNESCO

ENVIS Centre, Department of Environment, Government of Tamil Nadu

Panagal Building, No.1, Jeenis Road, Saidapet, Chennai-600 015. Tel: 044 24331243
Fax: 044 24336594 Email: tn@envis.nic.in Website: www.tnenvis.nic.in

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Water Resources of Tamil Nadu

Arungjunai Kaattha Ayyanar temple tank, Thiruchendur

W
ater is the elixir of life, a precious gift of harnessed by impounding the available water in 62
nature to mankind and millions of other large dams, 8 small dams, 5 drinking water reservoirs
species living on the earth. It is fast and 39,202 tanks (PWD Policy Note 2007-08).
becoming a scare commodity in most parts of the
world. Though water is available in the universe in
huge quantity in the order of 1400 x 106 km3, only 3%
of the waters in the universe is fresh water. Among
the fresh waters only about 5% of them or 0.15% of
the total world waters are readily available
for beneficial use (Environmental Planning
Frame Work, 2001).

In Tamil Nadu there are about 34 river basins, which

are grouped into 17 major river basins, all flowing
eastwards from the Western Ghats and Deccan
Plateau. Out of the 17 river basins, many basins are
water deficient and some have surplus water. The
population and area of Tamil Nadu are 7% and 4%
respectively of that of India, but the available water
resources are only 3%. Even though the annual
average rainfall is in the order of 925 mm there are a
number of rain shadow regions receiving less than or
around 400 mm rainfall making them drought prone.

In Tamil Nadu, the surface water potential is about

853 TMC, which includes 261 TMC from neighboring
States; while ground water potential assessed is about
790 TMC. The demand for water is continuously on
the rise with the growth of population, industry and
agriculture while there is no rise in the availability of
water. Surface water resources have been fully Map 1. River Map of Tamil Nadu

Front cover: Vennar river, Tanjore 2

In Tamil Nadu nearly 73% of the total area of the
State is occupied by a variety of hard & fissured
crystalline rocks like charnockite, gneisses and
granites. As per the estimate updated recently, 85%
(671 TMC) of the total ground water potential in Tamil
Nadu has been developed and being utilized. Out of
385 revenue blocks, 175 revenue blocks are over
exploited and critical, 8 blocks are saline, 105 blocks
of semi-critical and 97 blocks of safe category are
available for developing the left over 15% of the
potential (PWD Policy Note 2007-08).
Fig. 2. Open drainage system at Tiruchendur taluk
The three main sources of surface irrigation in the
State are rivers, tanks and wells. There are 39,202 Some of the important environmental concerns are
tanks, 2,295 irrigation main canals and 20,26,276 Excess application of fertilisers and pesticides
irrigation wells in the State. Management of water has affected groundwater quality in certain
resources in the state of Tamil Nadu has assumed pockets; high levels of nitrates are observed
considerable importance due to growing needs and in the Western districts.
conflicting nature of interests by various sectors. Many
of the river basins are water stressed due to limited Naturally occurring fluoride is a serious problem
supply and ever expanding demands. Apart from the particularly in the Western districts of the
agricultural needs, the state has to supply domestic State.
and drinking water to an increasingly urbanized and In the black cotton soil areas of the State,
dissolved salts are high.
Effluents from the leather industry have
contaminated the groundwater in the Palar
basin.
Effluents from the textile industry and dyeing
industry have affected the groundwater in the
Noyyal basin.
Industrial pollution in various industrial estates/
zones has affected groundwater quality.
Seawater intrusion has taken place in some
coastal areas due to over extraction of
Fig.1. Water deficit on river basin groundwater.
industrialized population in addition to the needs of In the coastal areas such as backwaters, estuaries
industries, fisheries, environmental flows and etc. salinity levels are high.
community uses (PWD Policy Note 2007-08).
II. Industrial effluents:
ENVIRONMENTAL CONCERNS:
There are more than 3,000 industrial units in Tamil
I. Surface water and Ground water pollution: Nadu which have been classified under the highly
polluting or “red” category. The total effluent
The river water is used downstream for irrigation or generated is about 6 lakh litres per day of which more
drinking by people/livestock. Contamination of the river than 5 lakh litre (85 per cent) is generated by large
has increasingly become a serious problem in many of industries. About 400 units discharge directly into
the river basins of the State. River basins like Palar, rivers. Of particular concern are the tanneries which
Tamirabarani, Cauvery, Noyyal, Bhavani and are located in Vellore, Kancheepuram, Dindigul and
Amaravathy face serious pollution problems due to Erode districts. The effluents have caused serious
industrial effluents. Sewage and sullage from problems in the Palar basin. Similarly, there are large
municipalities and settlements have also increased number of textile bleaching and dyeing units in
tremendously due to piped water supply and is Tiruppur, Erode, and Karur, which have contaminated
contaminating rivers, lakes, tanks, and ground water the Noyyal, Cauvery, Amaravathy and other water
(Tamil Nadu Development Report, 2005). bodies.

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There are five main industrial complexes in Tami Nadu: V. Excessive Surface and Ground Water
Manali/Ennore, Ranipet, Cuddalore, Mettur and Abstraction:
Tuticorin which have chemical, petro-chemical and
other industries. These complexes have also become In coastal aquifers the excessive pumping causes
environmental hotspots. There are cement units, saline water intrusion towards fresh water
distilleries, sugar, sago, paper, dairying, electroplating, aquifer, and mixing of saline water with fresh
chemical and fertilisers (Agro chemicals), mining water. This process of saline water intrusion is
industries, ores/mineral processing industries and a irreversible and causes the degradation of the
variety of other industries which are water consuming quality of groundwater with high concentration
and also generate large quantities of effluent (Tamil of TDS and minerals like chlorides and renders
Nadu Development Report, 2005). the groundwater unsuitable for the purposes for
which they were serving.
III. Catchment Degradation: Policy Initiatives taken by the Government to
protect water resources
In a catchment without trees, 80 to 95% of the
rainwater flows as run off and erodes surface soil. In a. National Water Policy:
the catchment area of most of river basins intensive
farming activities are taking place. Such farming The National Water Policy lays down general guidelines
operations and deforestation have exposed the topsoil, in preparing basin-wise master plan, priorities for
and resulted in changes of runoff pattern and soil water use, inter-basin transfer, etc. The National
erosion, affecting the reservoirs with heavy siltation. Water Policy enunciated by the Government of India
Uncontrolled grazing and movement of thousands of in 1987, which was further updated and adopted by
cattle are the most damaging activities in the catchment National Water Resources Council in April 2002, has
area, which disturbs the stability of the topsoil and leads recognized that water is a prime natural resource, a
to accelerate soil erosion (Environmental Planning basic human need and a precious national asset
Frame Work, Final Draft, 2001). (Environmental Planning Frame Work for Water
Resources Final Draft, 2001).
IV. Siltation in Rivers and Reservoirs:
b. State Water Policy:
The problem of siltation in reservoirs has become
Tamil Nadu adopted a State Water Policy in 1994 along
alarming, since the silt deposited in the reservoirs or
the lines of the National Water Policy of 1987.
tanks decreases the capacity of the reservoirs thereby
Subsequently, the National Water Policy was revised
reduces the utility of them for various purposes. The
in 2002. Some of the major aspects of the policy are
studies on the sedimentation problems carried out in
as follows: (Tamil Nadu Development Report, 2005)
33 reservoirs in Tamil Nadu reveal that there is a loss
in capacity of more than 50% in two reservoirs viz., Need for considering socio-economic aspects
Kundha and Glenmorgan, and more than 30% capacity of water resource projects.
loss in other 8 reservoirs (Environmental Planning Need for basin wide planning for equitable water
Frame Work, Final Draft, 2001). use.

4 Tamirabarani river at Tirunelveli

 Management and development of ground water f. Ground Water Regulation:
resources. The Tamil Nadu legislature passed the Ground Water
Watershed management in rain fed areas. (Development and Management) Act and the Act
Management of water quality and need for a came into force after receiving the assent of the
hydrological database for planning and President in March 2003. A Tamil Nadu Ground
management. Water Authority has been set up to direct and regulate
the development and management of the ground
Need for proper pricing of water in different water resources of the State. The Authority has the
sectors. power to notify areas for regulation. Tamil Nadu
Ground Water Act is in consonance with the rules
c. Management of Industrial Effluents: under the Environment Protection Act, 1986 by
which a Central Ground Water Authority was
The Government of India and the Government of constituted. The Central Ground Water Board
Tamil Nadu have enacted acts for prevention and functions in conjunction with the CGWA (Tamil Nadu
control of water pollution. Regulations were framed Development Report, 2005).
to monitor and control the discharge of effluents from
each industry and specifications were laid down for g. Interlinking of Rivers:
the quality of effluents to be discharged on land or
into water bodies after treatments. The Government Government of India formulated in 1980 the National
has passed orders banning the operation of highly Perspective Plan for the water resources development
polluting industries within 1 km from the embankment in the country. The plan consists of (a) Himalayan
of rivers and reservoirs. The Government has also River Development Component, and (b) Peninsular
passed orders imposing total ban of setting up of any River Development Component. The second one
of highly polluting new industries envisages diversion of surplus water
within 5 km from the rivers of of Mahanathi to Godavari and further
“Government has transfer from Godavari to water short
Cauvery and its tributaties, Pennaiyar,
passed orders banning Krishna, Pennar, Palar, Cauvery and
Palar, Vaigai and Tamirabarani (Tamil
the operation of highly Vaigai rivers. It also envisages
Nadu Development Report, 2005).
polluting industries diversion of surplus waters of the
within 1 km from the West flowing rivers for the benefit of
d. Water Cess:
embankment of rivers the drought prone areas. In order to
The Water (Prevention and Control and reservoirs.” study and examine the feasibility of
of Pollution) Cess Act of 1977 diverting the surplus waters, the
empowers the State Pollution Control Boards to levy Government of India constituted the National Water
a cess on industries based on their water Development Agency (NWDA) in 1982. The NWDA
consumption. If they comply with the provisions of has proposed interlinking of the Peninsular Rivers
the Water Pollution Act of 1974 and the including rivers in Tamil Nadu (Tamil Nadu
Environment Protection Act 1986, the cess is Development Report, 2005).
correspondingly reduced. In Tamil Nadu, the cess is
levied by the Tamil Nadu Pollution Control RIVER CONSERVATION PROJECTS IN
Board on water consuming industries TAMIL NADU:
(Tamil Nadu Development Report, 2005).
Environment Management Agency of Tamil Nadu
(EMAT) of the Department of Environment is in
e. Formation of River Basin Boards:
charge of coordination of National River Conservation
Plan (NRCP) and National Lake Conservation Plan
The National and State Water policies recommend
the management of water resources at the river (NLCP). The objectives of NRCP are to improve the
basin level. As part of the Water Resources water quality of major rivers, through selected pollution
Consolidation Project, the Government of Tamil abatement schemes. The important works being
Nadu has approved the creation of river taken up under the NRCP includes interception and
basin boards for the Palar and the diversion of sewage, laying of sewer lines,
Tamirabarani basins. River basin management construction of Sewage Treatment Plants (STP),
committees have been set up to monitor the water providing low cost sanitation, bathing ghats, gasifier
related activities of different agencies and users crematoria, dhobi khana, river front development,
(Tamil Nadu Development Report, 2005). improvement to bathing ghats etc.

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a. Pollution Abatement in Cauvery, under NRCP
– Five Old Towns:

Pollution abatement in river cauvery has been taken

up along the most polluted stretches at Erode, Bhavani,
Komarapalayam, Pallipalayam and Tiruchy towns
from 1996. The project comprises of a. Core Schemes
b. Non-core schemes. Under Core schemes,
interception and diversion as well as sewage treatment
works are being implemented through Tamil Nadu
Water Supply and Drainage Board (TWAD).
Table 1. Pollution abatement in five old Towns Fig. 3. Sewage Treatment Plant at Koyambedu, Chennai
MLD of Sewage Technology The project mainly endeavours to intercept over 314
S.No. Towns sewage outfalls joining the Chennai City Waterways
to be treated Adopted
1. Bhavani 03.94 WSP viz., Cooum, Buckingham Canal, Adyar, Otteri Nullah,
2. Erode 25.17 WSP&UASB Captain Cotton Canal and Mambalam drain. Special
3. Kumarapalayam 06.00 WSP mention is made on capturing methane in the four
4. Tiruchy 39.00 WSP
modern STP’s setup under this project. Electricity is
generated from the methane gas and the modern STP’s
5. Pallipalayam 06.80 -----
are self reliant on electricity as well as reducing the
WSP: Waste Stabilization Pond,
UASB: Upflow Anaerobic Sludge Blanket Reactor Green House Gas emission.
b. Pollution abatement in river Cauvery, Vaigai d. National Lake Conservation Programme
and Tamirabarani under NRCP - Seven (NLCP):
Additional Towns:
Environmental upgradation through bioremediation
Pollution abatement of the seven additional towns along of Ooty and Kodaikanal Lakes is being undertaken
river Cauvery, Vaigai and Tamirabarani has been under the National Lake Conservation Programme.
approved by the GoI. These integrated projects will These works are being executed by the Tamil Nadu
not only help in river cleaning but also provide better Water Supply and Drainage Board, the Public Works
health and hygiene to the people through provision of Department and the local bodies. Revival of Ooty
under ground sewerage. For treating the sewage, lake has been completed. Ootylake has become
technologies like Activated Sludge Process (ASP) and clean after treatment.
Waste Stabilisation Ponds (WSP) and extended
aeration have been adopted.
Table 2. Pollution abatement in seven additonal towns

S.no. Towns Name of the MLD Sewage Technology

river treated Adopted
1. Tiruchy Cauvery 58.00 WSP
2. Madurai Vaigai 99.00 WSP
3. Tirunelveli Tamirabarani 24.20 WSP
4. Karur Cauvery 15.00 EA
5. Thanjavur Cauvery 28.05 ASP
6. Kumbakonam Cauvery 17.00 ASP
7. Mayiladuthurai Cauvery 8.30 WSP
Total 249.55 Fig.4. Cleaning of Ooty lake
EA: Extended Aeration, WSP: Waste Stabilisation Pond,
ASP: Activated Sludge Process e. Water Quality Monitoring:
c. Chennai City River Conservation Project National River Conservation Directorate has
(CCRCP): sanctioned “Monitoring and Database Management
of the water ways of Chennai city” to the Centre for
Government of India has approved a project for Environmental Studies (CES), and Institute of Ocean
intercepting and treating sewage in six Chennai City Management (IOM), Anna University for monitoring
Waterways. The Chennai City River Conservation 17 parameters in 24 points in Adyar, Cooum river,
Project is being implemented through Chennai Buckingham canal and Mambalam canal and at inlet
Metropolitan Water Supply and Sewerage Board. and outlets to study the performance of STPs.

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TECHNOLOGIES ADOPTED FOR THE II. Bioremediation:
TREATMENT OF SEWAGE:
It is a process where a specialised consortium
In the past, the waste stabilization pond technology of Micro-organisms are applied to the water
was used for treating sewage. For treating one million body aiming to start corrective action, degrade the
litres of sewage a day, 2.5-3 acres was required. Now organic deposits, eliminate eutrophication and restore
new technologies such as fluid aerobic bioreactor, the equilibrium of the lake. This technology aims at
sequencing batch reactor and modified activated providing the right type of microbes, at the right time
sludge process have emerged. The new technologies and equipped with right environmental conditions. Bio
are cost effective and require less land. products contain specialised non-pathogenic, naturally
occurring bacteria, yeast & fungi that are specially
I. Activated Sludge Process: selected for their biodegradation capacities. These
micro organisms are ‘Biofixed’ on a special porous
Activated Sludge Process (ASP) is an operation matrix of calcium carbonate, called as ‘coccolith’. It
whereby a portion of the activated sludge as from contains a very high concentration of living organisms,
secondary clarifier is returned to be added upto 6 billion per gram. When the bio products are
to the effluent from a primary clarifier to form a mixed applied over the water body, soluble phosphates are
liquor, which is subsequently aerated and from precipitated and immobilized organic matter is
which the activated sludge is later removed in the degraded. In Tamil Nadu, Ooty lake of Nilgiris district
secondary clarifier. The process derives its was revived with the help of bioremediation technique,
name from the fact that settled sludge containing under NLCP.
living, or active, microorganisms is returned to III. Upflow Anaerobic Sludge Blanket Reactor:
the reactor to increase the available biomass and speed
up the reactions. It may be either a completely In a UASB reactor, the treatment tank consists of an
mixed or plug - flow process. The process is upflow reactor with a feed inlet distribution system at
aerobic, with oxygen being supplied by the bottom of the reactor and a gas-solids-liquid (three
dissolution from entrained air. Activated sludge phase) separator at the top. Waste water is evenly
processes consist of a tank within which distributed over the reactor bottom through feed inlet
the biological reaction occurs, a settling tank, a recycle pipes and flows upwards through a bed of anaerobic
pumping system, and an aeration system. sludge in the lower part of the reactor called digestion
The advantage of this technology includes lesser compartment. During the passage through the sludge
space, higher degree of treatment (80-95 % of BOD bed, particulate matter is entrapped and the degradable
removal and 90-95 % of Coli form removal) and free matter is completely or partially digested. Dissolved
from odour or fly nuisance, but maintenance organic matter is removed from the solution by the
cost is higher than the other technologies. anaerobic bacteria and converted into biogas and a
Another advantage is that electricity can be generated small fraction into new bacterial biomass.
from this process through bio methanation. The remaining water-sludge mixture enters a settling
Under CCRCP four STP of total capacity zone where the sludge can settle and flow back into
264 MLD were constructed, which have the digestion compartment. After settling, the water is
generated electricity power from October 05 to collected in effluent gutters and discharged out of the
February 06. This has twin benefits in reducing Green reactor. The advantage of UASB is that it consumes
House Gas emission and also reducing the O & M costs. less energy, generates methane rich biogas, removes
75% of COD, 80% of BOD and 80% of TSS removal
Flow diagram and retains N, P, K in the sludge.

Fig. 5. UASB reactor diagram

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The International observance of World Water Day is
an initiative that grew out of the 1992 United Nations
Success story of Rainwater Harvesting
Conference on Environment and Development
(UNCED) in Rio de Janeiro. The theme for World Tamil Nadu Government amended the Tamil Nadu
Water Day 2007, is “Coping with water scarcity” Municipalities Building Rules Act (1972) making RWH
compulsory in all existing buildings in the entire state and
which is celebrated each year on 22nd March. This
also passed Rain water Harvesting bill making rainwater-
year’s theme highlighted the increasing significance harvesting structure mandatory for all the buildings. This
of water scarcity worldwide and the need for scheme, which was first of kind in the country, more than
increased integration and cooperation to ensure 95% of the residents in the entire state put up RWH systems
sustainable, efficient and equitable management of in order to comply with law. A survey conducted by Rain
scarce water resources, both at international and local center, Chennai revealed that in the open dug wells which
levels. had gone dry a few years back came back alive and were
filled during the 2005 monsoon. The groundwater in the
“As population grows and development needs call bore wells, which had gone brackish has improved
for increased allocations of water for cities, considerably in quality and is being used even for drinking
and cooking. The Northeast monsoon rains during 2006,
agriculture and industries, the pressure on water
helped to sustain the groundwater table and also improve
resources intensifies, leading to tensions, conflicts it further. This was exhibited in Thiruvanmiyur, where the
among users, and excessive strain on the temple tank after having remained waterless for almost
environment.” thirteen years, got filled up to three feet from bottom.

- Dr. Jacques Diouf,

FAO Director-General

Weblinks on Water

1. Central Ground Water Board www.cgwb.gov.in

2. Ministry of Water Resources www.wrmin.nic.in
3. TWAD Board www.twadboard.com
4. Chennai Metro Water www.chennaimetrowater.com
5. Rainwater harvesting www.aboutrainwaterharvesting.com
6. Ramsar Convention www.ramsar.org
7. UN-Water www.unwater.org
8. World Water Day 2007 www.worldwaterday07.org
9. World Water Development Report www.unesco.org/water/wwap/wwdr2/
10. International Water Management Institute www.iwmi.cgiar.org
ENVIS Team
Thiru K.S. Neelakantan, I.F.S., Thiru K.S.S.V.P. Reddy, I.F.S., Dr. C. Thomson Jacob
Director Additional Director Senior Programme Officer

Dr. K.P. Raghuram Mr. J.D. Marcus Knight Ms. S. Indra Devi
Programme Officer Information Officer I.T. Assistant
Editorial Board: Editor-in-chief: Thiru K.S. Neelakantan, IFS., Director, Editor: Thiru K.S.S.V.P. Reddy, IFS., Associate Editor:
Dr. C. Thomson Jacob, Layout & Photographs: K. P. Raghuram, Printed at Nagaraj & Co., Chennai-41 Tel: 044 6614 9291
Disclaimer: The information in this newsletter has been compiled from various sources and does not necessarily depict views of the
ENVIS Centre, Department of Environment, Government of Tamil Nadu.