CLIMATIC CHANGES AND ITS CONTROLON WATER RESOURCES IN VELLAR

RIVER BASIN

by

Mr. K. Santhanam, Dr. R. Kannan and Dr. NethajiMariappanResearch and Development

Sathyabama University,Chennai -119

Vellar River Basin

One of the 17 major river basins of Tamil Nadu

Index map showing Vellar Basin

• Administrative boundaries :Dharmapuri, Salem, Viluppuram, Cuddalore, Namakkal, Perambalure and Tiruchi Districts

• Total Geographical area :7521 sq. km

• Physiography :Kalvanrayan Hills in north and Kollimalai-Pachchamalai hills in the south

• Regions :Western hilly terrainCentral Hill valley complex terrainEastern deltaic plain and coastal

region

Administrative and Sub basin boundary map

Drainage Map of Vellar basin

Tributaries

-Vasista Nadhi

-Swetha Nadhi

-Chennar River

-Anaivari Oodai

-Manimutha Nadhi

-Gomukhi Nadhi

-Periya Ooadi

Vellar River basin drainage Map

RELIEF MAP

Maximum Elevation : 1266 m (Kalvarayan Hills-South slope)

Ranges of Elevation : 110 m to 1183 m In the northwestern part of Vellar Basin

Minimum elevation :20 to 40 m (Chidambaram)

Relief map of Vellar basin

GEOLOGY

Western part of the basin – Archean Group of rocks ( Magnetite Quartzite, charnockite,

Granulite and Amphibolite)

Eastern part - Sedimentary formations of Cretaceous

Argillaceous sand stoneCalcareous sand stoneShale and Lime stone

Tertiarysand stone , lignite, clay and shale

QuaternaryBeach, sand dunes, black clay, flood plians and alluvium

Vellar River Basin Geology Map

Vellar River Basin satellite image mosaic

Vellar River basin Geomorphology Map

Vellar River basin Southeast monsoon Rainfall

Vellar River basin Northwest monsoon Rainfall

RASIPURAM

0.0

200.0

400.0

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1400.0

1600.0

1971

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1972

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1973

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Year

AN

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in

mm

ANNUAL RF IN mm 5 YEARS MOV. AVE. ANNUAL AVG. Linear (ANNUAL RF IN mm)

SENDAMANGALAM

0.0

200.0

400.0

600.0

800.0

1000.0

1200.0

1400.0

1971

-72

1972

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1973

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1974

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1975

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1976

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1977

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1978

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1979

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1980

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1982

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1983

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1984

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1985

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1987

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1988

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1989

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1990

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1991

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1995

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1999

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Year

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ANNUAL RF IN mm 5 YEARS MOV. AVE. ANNUAL AVG. Linear (ANNUAL RF IN mm)

ATHUR

0.0

500.0

1000.0

1500.0

2000.0

2500.0

1971

-72

1972

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1973

-74

1974

-75

1975

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1976

-77

1977

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1978

-79

1979

-80

1980

-81

1981

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1982

-83

1983

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1984

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1985

-86

1986

-87

1987

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1988

-89

1989

-90

1990

-91

1991

-92

1992

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1993

-94

1994

-95

1995

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1996

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1997

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1998

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1999

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2000

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2001

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2002

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2003

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Year

AN

NU

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RF

in

mm

ANNUAL RF IN mm 5 YEARS MOV. AVE. ANNUAL AVG. Linear (ANNUAL RF IN mm)

CHIDAMBARAM

0.0

500.0

1000.0

1500.0

2000.0

2500.0

3000.0

1971

-72

1972

-73

1973

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1974

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1975

-76

1976

-77

1977

-78

1978

-79

1979

-80

1980

-81

1981

-82

1982

-83

1983

-84

1984

-85

1985

-86

1986

-87

1987

-88

1988

-89

1989

-90

1990

-91

1991

-92

1992

-93

1993

-94

1994

-95

1995

-96

1996

-97

1997

-98

1998

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1999

-00

2000

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2001

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2002

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2003

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Year

AN

NU

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RF

in

mm

ANNUAL RF IN mm 5 YEARS MOV. AVE. ANNUAL AVG. Linear (ANNUAL RF IN mm)

TECHNICAL CONCLUSIONS

Western part of Vellar river basin receives more rainfall during south west monsoon

Due to elevation (1300 m) and Compactness of hard rock, surface water goes as runoff to the eastern sedimentary formation

Due to compactness recharge is not possible in the western and central portions as geological conditions and geomorphological conditions are not favourable

Year by year rainfall quantity is decreasing

TECHNICAL CONCLUSIONS

In the eastern part Northeast monsoon rainfall is predominant

In addition to south west monsoon rainfall, water from western part is also recharging the sedimentary aquifer

Hence Aquifer is fully saturated in south west monsoon

During North East monsoon rainfall water goes as surplus water to sea and heavy flood is caused in Chidambaram and Cuddalore Taluks

RECOMMENDATIONS In the upstream side of western part of the river basin more artificial recharge structures like check dams percolation ponds, recharge pits have to be constructed in order to retain water in upstream side so that south west monsoon water will not go to down stream side.

In Eastern side water level may be lowered for irrigation purposes so that Northeast monsoon rain water will reach the aquifer and gets recharged

By these procedures the surplus water running to the sea can be prevented. Heavy water logging in the coastal region can be avoided