ISLAMABAD, July 13: The Indus River System Authority (Irsa) has been compelled to release about 45,000 cusecs of water, over and above the irrigation and power requirements, because of higher inflows and operational constraints mainly at Tarbela Dam, it is learnt.
Informed sources told Dawn that Irsa was releasing about 317,140 cusecs of water against the provincial irrigation demands of 273,000 cusecs.
They said the irrigation authorities could not store more than 26,000 cusecs of water against total inflows of about 182,000 cusecs.
More than 156,000 cusecs of water was being released from Tarbela because of technical reasons that require that water level should not rise by more than 1 foot per day.
The maximum water requirement of the Water and Power Development Authority (Wapda) for running all the power units at Tarbela is about 115,000 cusecs which means that more than 41,000 cusecs of water is being released over and above provincial irrigation requirements and power needs of Wapda. As a result, all power units at Tarbela are producing electricity, a blessing in disguise for Wapda that was otherwise facing power shortages. In addition, another 35,000 cusecs or so is being released through the tunnels.
The sources said a total of about 250,000 cusecs of water was surplus in the system. Water level at Tarbela dam has now reached 1,514 feet against its dead level of 1,369 feet.
Although, maximum filling level at Tarbela is 1,550 feet, yet water level must not be raised more than a foot per day to avoid any damage to the dam structure. Besides 156,000 cusecs of water being released from Tarbela, about 63,000 cusecs of water is added to the Indus zone by river Kabul besides some other flows from big and small rivulets.
Meanwhile, the Chashma-Jhelum canal has been closed for “unusual repair and maintenance” works on the request of Wapda authorities because of dilapidated conditions of its embankments.
Wapda had sought closure of the canal for two months but the provinces and Irsa jointly decided to allow only 50 days of closure from July 11 to August 31.
During this period, Punjab’s irrigation requirements at Tarimu would be met from Jhelum and Chenab zones, instead of Indus zone that is connected to Tarimu through CJ-Link.
The sources said the overall water flows have dropped from 325,000 cusecs in the Indus zone to about 182,000 cusecs in recent days but rising temperatures in the catchments had already gone up to 35 centigrade, raising hopes that river flows would again jump significantly in the next few days.
The irrigation authorities have also been informed that a very good system was developing and there would be good rains sometime next week. They said a total of 6.3 million acres feet of water have already gone downstream Kotri during the current Kharif season against an average of 2.5 MAF during this period.
The sources said Irsa was also releasing about 15,000 cusecs of water from Mangla dam over and above the irrigation requirements.
Wapda is currently drawing 40,000 cusecs from Mangla against its total inflows of about 39,000 cusecs of water. From next week, releases for power generation from Mangla would be brought down to 10,000 cusecs, instead of 15,000 cusecs, in addition to the irrigation needs.
Water level at Mangla currently stands at about 1,194 feet against its dead level of 1,040 feet and maximum limit of 1,210 feet.
The irrigation authorities were also releasing about 256,000 cusecs from Chashma barrage against inflows of 263,500 cusecs.
