ISLAMABAD, Nov 18: Water shortage during the current Rabi season is feared to be ‘unusual’ and much higher than estimated by the Indus River System Authority (Irsa) at 22 per cent last month, it is learnt.

Informed sources told Dawn on Sunday that the total storage in reservoirs at present was about five million acre feet (MAF), almost 30 per cent lower compared to last year. Likewise, river flows have declined significantly in the recent few weeks. The cumulative flows in four big rivers last year were almost 30 per cent higher at 55,000 cusec compared with about 40,000 cusec this year. Last year, the nation faced about 15 per cent water shortage.

Moreover, the Pakistan Meteorological Department has informed the irrigation authorities of a possible emergence of a La Nina like drought conditions in the days ahead during the current season and thereafter. In such circumstances, Irsa and Wapda authorities are anticipating much higher water shortage for the season that may affect major crops negatively, sources say.

Sources said Irsa was approaching the provincial governments for an immediate review meeting of its advisory committee next week – most probably after Nov 22 - to examine the overall weather conditions, revise water availability estimates and restructure water distribution plan accordingly to meet the provincial water indents.

The situation has further aggravated owing to water releases by Wapda authorities from Mangla dam to meet electricity requirements. Separately, an emergent meeting of the Irsa, Wapda and irrigation authorities has been convened on Nov 22 to seek an explanation from Wapda’s member water as to why unauthorised water releases were made out of Mangla dam at a time when the country was faced with irrigation shortages. The meeting has been called on written protests of Punjab government, the sources say.

According to the Met Office, the magnitude of the current below-normal sea surface temperature was in the middle range of La Nina events that have been found in the history. Pakistan experienced La Nina effect during 2000-2002 which had badly impacted the crop output.

Last year, the country managed to have bumper crops in Rabi season despite 14 per cent water shortages due to better water management and fortunate timing of rains. Last year, total availability was 31.184 MAF. Under the 1991 water accord, the availability should be 37 MAF.

The advisory committee of Irsa had last month forecasted 22 per cent water shortage for the season and decided, despite Sindh’s opposition, to distribute provincial water shares on the basis of historic use. The anticipated water availability for Rabi 2007-08 was put at 28.64 MAF and a shortfall of 22 per cent, but that situation seemed to have changed very significantly, sources said.

The two smaller provinces are traditionally exempted from shortages and the total water shortage is usually shared by the two larger provinces – Punjab and Sindh despite the latter’s opposition.

Wheat, gram, lentil, tobacco, barley and mustard are major crops of the Rabi season that begins on Oct 1 and ends on Apr 30.