Dear student,
The water of river Cauvery was shared between two states of India that is Karnataka and Tamil Nadu. There were no disputes as per interstate agreements of 1872 and 1924. The dispute started when Karnataka wanted to build 4 new reservoirs within the tributaries of this river. Even after gaining no approval for funds, neither from Planning Commission nor from the Central government, Karnataka carried on building the reservoirs by its own fund. Tamil Nadu protested against it as some portion of water was diverted towards Karnataka. Tamil Nadu forced the centre to create a tribunal. The Centre did not take effective actions for which Tamil Nadu reached to Supreme Court so that it can order the centre to take necessary steps. Finally, in the year 1990, the tribunal was formed. Thus Cauvery dispute falls under original jurisdiction as Article 131 states any disputes between centre or states will come under original jurisdiction under the provision of the Supreme Court.
Regards