The river basin is 257,000 km², and the States of Maharastra, Karnataka and Andhra Pradesh contributes 68,800 km² (26.8%), 1, 12,600 sq.k.m. (43.8%) and 75,600 km² (29.4%) respectively.
Due to the inter state nature of the river and the multiple parties concerned, disputes arose between the states of Karnataka, Maharashtra and Andhra Pradesh over sharing of the waters. The Government of India constituted the Krishna Waters Disputes Tribunal in 1969 under the Inter State Water Disputes Act of 1956. This was headed by R. S Bachawat a former judge of the Supreme Court.
The Bachawat commission went over the matter in detail and gave its final award in 1973. While the Tribunal had in its earlier report detailed two schemes, Scheme A and Scheme B, the final award only included Scheme A and Scheme B was left out. Scheme A pertained to the division of the available waters based on 75% dependability, while Scheme B recommended ways to share the surplus waters.
The government took another three years to publish the award in its Extraordinary Gazzette dated …. 1976. With that the final award(Scheme A) of the KWDT became binding on the three states.
The KWDT in its award outlined the exact share of each state. The award contended based on 75% dependability that the total quantum of water available for distribution was 2060TMC. This was divided between the three states in the following manner.
| Maharashtra | 560 TMC |
| Karnataka | 700 TMC |
| Andhra Pradesh | 800 TMC |
In addition to the above, the states were allowed to use regeneration/return flows to the extent of 25, 34 and 11 TMC respectively. Further, the Tribunal has allowed the States to utilise their allocated share of water for any project as per their plans.
Including regeneration, the total water available to Karnataka for utilisation is 734 TMC.Out of this, Upper Krishna Project has been allotted with 173 TMC.
The tribunal also made it clear that in case any one of the states were not to co-operate in sharing surplus water in the above ratio, Parliament should take a decision to distribute the surplus water through en enactment (Page 163 KWDT report Vol.II).
However, Scheme B involved the constitution of an authority(Krishna River Valley Authority) to ensure the implementation of the scheme. The constitution of such an authority, though, was outside the powers of the tribunal under the Inter State Water Disputes Act of 1956. As a result, Scheme B was left out of the Tribunal’s final award and Scheme A alone was presented to the government for final notification in the Gazzette.
Therefore, for the time being, Andhra Pradesh has been given permission to make use of any surplus waters though it cannot claim any rights over the same. This has, however, over the decades resulted in Andhra Pradesh utilizing waters far in excess of its 811 TMC share.
In Sep 2003, the second KWDT, KWDT-II was constituted by the Govt of India following requests by all three states. This tribunal has started its proceedings from 16.07.07.