Brief Description

• The Cauvery River rises in the Western Ghats and flows in eastwardly direction passing through the states of Karnataka, Tamil Nadu, Kerala and Pondicherry before it drains into Bay of Bengal. The basin lies between latitudes 10⁰ 05’ N and 13⁰ 30’ N and longitudes 75⁰ 30’ E and 79⁰ 45’ E.
• It is bounded on the west by the Western Ghats, on the east and south by the Eastern Ghats and on the north by the ridges separating it from the Tungabhadra (Krishna) and Pennar basins.
• The total length of the river from source to its outfall into Bay of Bengal is about 800 km. Of this, 320 km is in Karnataka, 416 km is in Tamil Nadu and 64 km forms the common boundary between Karnataka and Tamil Nadu States.
• The Cauvery basin extends over an area of 81,155 km², which is nearly 24.7% of the total geographical area of the country
• The basin lies in the States of Tamil Nadu, Karnataka, Kerala and Pondicherry.
• The shape of the basin is somewhat rectangular with a maximum length and breadth of 360 km and 200 km, respectively.

Physiography

Physiographically, the basin can be divided into three parts: the Western Ghats area, the Plateau of Mysore and the Delta. The delta area is the most fertile tract in the basin.

Soil of the Basin

The principal soil types found in the basin are black soils, red soils, laterites, alluvial soils, forest soils, and mixed soils. Red soils occupy large areas in the basin. Alluvial soils are found in the delta areas. The culturable area of the basin is about 58,000 km² which is about three percent of the culturable area of the country.

Drainage Area (Km²)

Statewise Drainage Area (Km²)

Name of State

Drainage area

Tamil Nadu

43,867

Karnataka

34,273

Kerala

  2,866

Pondicherry

    149

Total Drainage Area ( Km²)

81,155

Soil and Land use of Basin

The main soil types found in the basin are red and yellow soils.  Mixed red and black soils occur in parts of the Bolangir, Sambalpur, and Sundargarh districts of Orissa.  Laterite soil is found in the lower parts of Orissa. The deltaic soil is found in the coastal plains of the Mahanadi. Black soil and sandy soil with "Kankar" are the main soils found in the part of basin lying in Chhattisgarh.

Except in the Chhatisgarh and coastal plains, the basin has an extensive area under forests. Forest and agriculture are the main stay of the people in the interior parts of the basin.  The Chhatisgarh and coastal plains, with a high incidence of rainfall, are predominantly rice growing areas.

Geology of the Basin

The geology of the drainage basin is predominantly formed from Precambrian rocks, principally the Dharwars, Peninsular granitic Gneiss, Charnockites and the Closepet Granite. The Dharwar metamorphics mainly comprise of phyllites, slates, schists with chlorite, biotite, garnet, and hornblende. Accompanying these are greenstones and quartzite. The Closepet Granite of the upper reaches of the Cauvery basin is a pink granite consisting mainly of quartz, plagioclase, microcline, perthite, and subordinate hornblende. Over the main basin, the peninsular granites and gneisses comprising of biotite granitic gneiss, hornblende granitic gneiss are widely found. The Charnockites are confined to the Nilgiri Range in the central part of the drainage basin. These are represented by gabbros, olivine norites, and pyroxene. Cretaceous sediments crop out in the coastal region and consist of conglomeratic sandstone, coralline limestone, and shale.

Climate of Cauvery

Basin

Cauvery basin experiences tropical climate. Here, the main climatic feature is the monsoon rain. The north-east monsoon provides the greater portion of the annual precipitation. The far north-western part of the drainage basin has a per-humid climate which passes eastwards into humid, moist sub-humid, dry sub-humid and semi-arid zones. The recorded maximum and minimum temperatures are 44°C and 18°C respectively.

The highest rainfall in the basin is received along the western border of the basin during the southwest monsoon. The eastern side of the basin gets most of the rain during the northeast monsoon. Depressions in the Bay of Bengal affect the basin in the monsoon, causing cyclones and widespread heavy rains 

Water Potential of the Basin

Surface Water potential

66.88 km³

Ground Water potential

16.46 km³

Water Utilization

Surface Water Utilization

Drinking purposes

Irrigation purposes

Ground Water Utilization

Drinking purposes

Irrigation purposes

Major Tributaries with drainage area in sq. km.

The important tributaries joining Cauvery in the Coorg district are the Kakkabe, the Kadanur and the Kummahole. Cauvery then enters the Mysore district where important tributaries joining the river from the left are the Harangi, the Hemavathi, the Shimsha and the Arkavathi. The tributaries joining it from the right are the Lakshmanathirtha, the Kabbani, and the Survanavathi. Further down, the river enters Tamil Nadu state where the many tributaries, namely, the Bhavani, the Noyil, and the Amravathi join it.

Major Projects

Krishnaraja sagar dam, Nugu, Mettur and Grand Anicut projects

Water Quality

Several studies were made by the Central Pollution Control Board to ascertain the status of water quality in the Cauvery River. The results show that at many places, the quality of water was quite poor compared to what was the desired class.

Problems in the  Basin

Occasional flood problem in lower reaches and delta areas of Cauvery river.

Mythology

The Cauvery River, also known as Dakshin Ganga or 'Ganga of South', is one of the holy rivers of South India.