1. CLIMATIC CHANGES AND ITS CONTROL
ON WATER RESOURCES IN VELLAR RIVER BASIN by
Mr. K. Santhanam, Dr. R. Kannan and Dr. NethajiMariappan
Research and Development
Sathyabama University,
Chennai -119

2. Vellar River Basin
One of the 17 major river basins of Tamil Nadu

3. Index map showing Vellar Basin

4. Administrative boundaries. :Dharmapuri, Salem, Viluppuram,
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 terrain
Central Hill valley complex terrain
Eastern deltaic plain and coastal region

5. Administrative and Sub basin boundary map

6. Drainage Map of Vellar basin
Tributaries
-Vasista Nadhi
-Swetha Nadhi
-Chennar River
-Anaivari Oodai
-Manimutha Nadhi
Gomukhi Nadhi
Periya Ooadi

7. Vellar River basin drainage Map

8. 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)

9. Relief map of Vellar basin

10. GEOLOGY Western part of the basin – Archean Group of rocks
( Magnetite Quartzite, charnockite, Granulite and Amphibolite)
Eastern part - Sedimentary formations of Cretaceous
Argillaceous sand stone
Calcareous sand stone
Shale and Lime stone
Tertiary
sand stone , lignite, clay and shale
Quaternary
Beach, sand dunes, black clay, flood plians and alluvium

11. Vellar River Basin Geology Map

12. Vellar River Basin satellite image mosaic

14. Vellar River basin Geomorphology Map

15. Vellar River basin Southeast monsoon Rainfall
Vellar River basin Northwest monsoon Rainfall

20. 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

21. 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

22. 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