The Hindu Centre for Politics and Public Policy reported:

Supreme Court has differed from the Cauvery Tribunal on fundamental issues: Mohan Katarki | The Hindu Centre for Politics and Public Policy

The Cauvery issue between the States of Karnataka and Tamil Nadu and their predecessor States has gone on for nearly two centuries. What is the raison d’etre for this long riparian conflict?

There is no single reason. It has been the combination of several reasons namely topography of the basin, outdated legal laws on natural flow theory and prescriptive rights, drought in upland areas in Mysore, etc. To begin with, the riparian conflicts broadly have a typical pattern and that pertaining to the River Cauvery is no different. The water in its natural course flows by gravity from source to the mouth, where most of the rivers split into deltaic shape. It is in this delta region, taking advantage of the natural flow, the irrigation is developed historically by natural system of channels and it is here where civilisation started.

This is true for Cauvery, Krishna, Godavari, Mahanadi, Indus, Ganges-Brahmaputra, Danube, Mekong, Mississippi, Nile, and Tigris. However, the advent of hydrant technology in the middle of the century changed the situation. The upstream States started building dams to store the water and use it by gravity flow after creating a required height. This was further propelled by mechanical pump sets and hybrid crops. This invited protest from the downstream states, particularly with regard to the rivers having delta. This conflict turned into a dispute between old users who claim historical rights such as right of appropriation, prescriptive rights or natural flow rights and the new users who claim territorial rights.