KARACHI, Sept 10: Water supply to the city from the Hub dam source will be suspended for 22 days with a gap of five days, starting from Sept 26, to undertake repair and desilting works of both Wapda’s Hub main and the KWSB’s Karachi Supply canals, sources told Dawn on Wednesday.

The repair and strengthening of both the canals is to be carried out in two phases. First from Sept 26 to Oct 5 and second from Oct 10 to 21. It is aimed at restoring 100 mgd of water to the city from the Hub dam on the eve of Ramazan.

The dam’s reservoir has attained its full supply mark of 339 feet on July 29 in the wake of the recent rains. At present, only 25 mgd of water is being released to the city from the source.

With the restoration of 100 mgd of water from the Hub source, the weekly water-holiday system which is in vogue in the city since October, 2002, is likely to be done away with, according to the sources.

The weekly water-holiday system was introduced in the localities getting their supply from the Indus source for diverting the same to the sprawling townships of Baldia, Orangi, North Karachi, Surjani, Shershah and SITE, all hooked to the Hub source.

Water to the city and Lasbella from the Hub source is first released to the 5.2-mile-long Hub main canal, and from there it passes through the 14-mile-long Karachi Supply Canal and 21-mile-long Lasbella branch canal before reaching the city and Lasbella.

The Hub main canal is maintained by Wapda. The Karachi supply canal which the Wapda handed over to the KWSB in 2001 is maintained by the city government’s water and sanitation department and the Lasbella branch canal by the Balochistan government.

The repair of the main Hub canal has been necessitated by the fact that its aqua-duct pillars have rusted to such an extent that Wapda officials manning the Hub dam warned in May that the pillars might collapse if more than 20 million gallons of water is released to the canal.

Similarly, the Karachi supply canal is also in a dilapidated condition with cracks at a number of places resulting in wastage of a considerable quantity of water owing to seepage and growth of weed.

“Had this repair work of both the canals been undertaken when the dam remained dry, there wouldn’t have been any suspension of supply from the source now,” said an engineer of the city government’s water and sanitation department.

Unfolding the details of the plan chalked out at a high-level meeting held here last week under the chairmanship of the additional chief secretary, Ghulam Sarwar Khero, the sources said that Wapda and the KWSB officials, had been asked to complete the canals’ repair, strengthening and desilting works in two phases (i.e. from Sept 26 to Oct 5 and from Oct 10 to Oct 21), so that the city starts receiving 100 mgd of water with the advent of Ramazan.

About the alternative arrangements for supplying water to the localities hooked to the Hub source during the suspension of supply, a senior official of the W&S department said that though the quantity of water currently being supplied to such areas from the Indus source via Ajmair Nagri and Board Office pumping stations would be increased, the gap between their supply might be extended beyond 102 hours.

In addition, the other major works to be undertaken during the suspension of supply from the Hub source include cleaning and strengthening of pipelines from the Hub pumping station, its 200-feet high-rising main, desilting of Hub reservoir, etc.