T is that time of the year when Punjab and Sindh come face to face over the distribution of river water or, more appropriately, over the sharing of water shortages in the Indus River system for the Kharif crops between themselves.

Theoretically, Irsa is supposed to allocate the available amount in accordance with the outdated 1991 Water Apportionment Accord. The second paragraph of the accord fixes the share of the provinces. However, owing to the unavailability of the envisaged amount of water in the rivers, Irsa has evolved a `three-tier formula` and has been distributing the shortages according to it for over a decade, despite Sindh`s objections.

The formula mostly relies on historical practice from 1978 to share water shortages and surpluses on a pro rata basis. It also exempts KP and Balochistan from sharing the shortages. That means only Punjab and Sindh will see a cut in their share. Sindh is opposed to it because of the impact of the regular shortages and the formula-based cut in its share of water that is meant for agriculture. For many years, the matter has been under the `active` consideration of the Council of Common Interests, which allows Irsa to apply the controversial three-tier formula year after year, in violation of the accord.

It is also that time of the year when the capacity, or rather the lack of it, of Irsa which is supposed to play the role of arbitrator in case of a dispute between the federating units under the accord to correctly estimate the shortages is exposed. Punjab and Sindh don`t see eye to eye when it comes to estimating the conveyance or system losses. Punjab says the losses are around 7pc to 8pc whereas Sindh insists that system losses range between 35pc and 40pc, particularly on its territory between the Chashma and Kotri barrages. That these kind of interprovincial disagreements and disputes are now a regular feature of our water distribution mechanism underlines the need for revisiting the three-decade-old accord. Much has changed since 1991. Pakistan is now one of the top 10 nations impacted by global warming and may soon become one of the most water-stressed countries in the world as the shortages increase. The federation and its units need to renegotiate a new water distribution agreement, free from the shortcomings and controversies of the existing one.