ISLAMABAD, March 29: With estimates of about five per cent average water shortage during Kharif season, the Indus River System (Irsa) is expected to distribute water among provinces on historical use basis, Dawn has learnt.

A senior Irsa official said that under maximum water availability estimates, the water shortage would be in the region of 3-7 per cent which means that average shortage would be about five per cent.

The technical committee of the IRSA meets here on Tuesday to finalize water distribution plan for Kharif season after incorporating demands of the provinces and taking into account latest forecast and data from Met Office and Wapda respectively.

The technical committee is also expected to finalize a plan to deplete Mangla and Tarbela dams on proportionate basis and simultaneously to ensure reasonable supplies to Sindh till close of the season by end-September.

Representatives of Wapda, Met Office, Nespak, Chief Engineering Organisation and all the four provinces would also attend the meeting. Sindh, Irsa sources said, would demand water distribution on Water Accord basis in view of a nominal water shortage forecasts but this could not be entertained.

The principle of shortage sharing on the basis of annual average uses, commonly known as historic uses currently holds the ground pending a decision by the government whether or not the dispute between Punjab and Sindh be referred to the Supreme Court for adjudication.

The Irsa official said the overall trend, snowfall on mountains and future forecasts indicate that water situation would be tight but easily manageable and not like big water shortages experienced during the last four years.

He said advisory committee of the Irsa is also expected to meet during the second week of April, followed by mandatory Irsa's mandatory meeting to approve the water distribution plan and dams depletion plan.

Under para-2 of the 1991 accord, the water distribution has to be made strictly on the basis of ratios agreed to in the apportionment accord while section 14 (2) required that in case of shortages the shares should be based on historic uses.

Water uses during the years 1977-82 of acute shortage are normally treated as historic uses which favour Punjab. Overall shortage in Kharif 2000 was 11 per cent, which increased to 18 per cent in Kharif 2001 and further to around 30 per cent in Kharif 2002.