Godavari - Cauvery Link Project - Cauvery Component
iasparliament
March 10, 2021
What is the issue?
Tamil Nadu recently launched its intra-State river linking project by building a canal from the Cauvery to the Vaigai and the Gundar, a part of the larger Godavari-Cauvery Link Project.
The rationale for the plan causes concerns given the environmental and geographical features of the region developed over the years.
What does the project aim at?
The Cauvery - Gundar link project forms part of the peninsular rivers’ development component of the National Perspective Plan.
The latter envisages diversion of surplus flows of the Mahanadi basin and the Godavari basin to the water-short Krishna, Pennar, Cauvery, Vaigai and Gundar basins in the South.
The Cauvery - Gundar link project seeks to divert surplus flows from the Cauvery to the water scarce southern parts of the State.
This component will be carried out in three phases:
First phase – linking Cauvery to the South Vellar river (118.45 km)
Second phase - linking the South Vellar and Vaigai rivers (110 km)
Third phase - linking the Vaigai with the Gundar river (34.04 km)
The first significant step towards the linking was made with the commissioning of the barrage across Cauvery at Mayanur in Karur district in 2014.
The barrage will form the head of the new link canal.
The link canal will carry the surplus waters from the Cauvery to the South Vellar, the Vaigai river and finally the Gundar.
The canal will have a capacity to carry about 6,000 cusecs of water.
What is the government’s rationale?
The Cauvery is perceived to carry surplus water.
This is mixing into the Sea unused, when the water demand for agricultural use is evident year after year.
So, the idea is to divert the surplus water through a canal, so as to irrigate farm lands.
The canal, of nearly 250 km, travelling North-South, will carry 6,000 cusecs of water from Kattalai barrage in the north end, to the Gundar river in the South.
What are the concerns with this approach?
The idea of surplus or deficit in terms of a river seems essentially flawed.
It all depends on the amount of water being used and for what.
The excess water flowing across the banks ought to be identified as flood; it is not surplus indeed.
In that case, floods are to be seen neither as wastage of water nor as surplus and so to be commercialised.
This is because floods do play a key role in a riverine ecosystem and the associated geographical features.
Why are floods significant?
The present day Cauvery delta region is largely a result of the deposits and sedimentation formed with floods in Cauvery river over generations.
All these resulted from the free flow of water along the entire course of the river from its various tributaries, canals and up to the streams and rivulets.
Excavations in the Cauvery banks and the region around, if done, would reveal this fact.
Floods thus play a key role in delta formation.
Moreover, the flooding at intervals and free flow of water along the river channel help preserve the biodiversity of the region, especially fishes.
The Cauvery River has already in place an old delta and a new delta.
The former one was formed naturally by Cauvery and its tributary Vennar.
The latter took shape as a result of constructing the Kallanai Dam (Grand Anicut) in the 1930s.
Now, the inter-state river link project is expected to make way for a new, third delta for the Cauvery.
The link river would notably pass in the north-south direction.
So, a possible delta formation over the course of time could interrupt the natural course of Cauvery and the natural geo-features in the region around.
This may not happen any soon but the idea of viewing floods as surplus water and commercialising it are disturbing trends to environment protection and conservation.
