The gigantic work pertaining to repair and desilting of Karachi Supply Canal, Hub Reservoir, Wapda Hub main canal, as well as plugging of leakage in major pipelines, had been scheduled to be undertaken in two phases with a gap of five days. The first phase was to start on Sept 29 and to complete on Oct 8. Water supply was to be resumed for the next five days before the start of the second phase of repair work on Oct 14. Normal supply to the city was to be resumed on Oct 24.
However, when cleaning of the Karachi Supply Canal and Hub Reservoir began on Monday, officials of the W&S department came to know that a huge quantity of silt — around three feet high in the canal and about 10 feet high in the reservoir — had deposited. As such, they decided to skip the gap in repair and desilting work and keep water supply from the source suspended throughout both the phases in order to complete the cleaning and linking work within the stipulated period.
However, the date for the resumption of supply to the tune of 100 million gallons per day from the Hub source has been kept the same i.e. Oct 24.
Well-placed sources in the W&S department said that the reason of silt in the canal and reservoir in such a huge quantity was that the desilting work was being carried out after a long period of 21 years, for the first time since the commissioning of the Hub dam project in 1982.
Attributing the huge quantity of water going waste to the massive rocks of silt as well as the cracks in the KSC channel, insiders said that had the W&S department carried out such works periodically and regularly, the city would have started getting 100 mgd of water from the dam shortly after July 29 when it had attained its fully supply level of 339 feet. Also, there would have been no water shortage problem in the areas hooked to the Hub source.
Although Wapda officials had been releasing 24 mgd of water into the Hub Canal before Sept 29, the day the supply was suspended, the W&S officials kept claiming that they had been receiving not more than 18 mgd at the Hub reservoir. This means that over six million gallons of water had been going waste every day while on way to the reservoir through the KSC course, obviously owing to the huge sit deposits and an unknown number of cracks.
However, the W&S officials who had constantly been maintaining that the Karachi Supply Canal is not in a poor condition, have now come out with the claim that there are two major factors contributing to the emergence of massive silt deposits in the canal and reservoir. They identify the factors as non-filtration of Hub source water, and the turbidity that becomes high in rainy seasons.
The sources said that following completion of repair and desilting works of Karachi Supply Canal and Wapda’s main canal, besides plugging of leakages in the main pipeline meant for the areas hooked to Hub source, Karachi start getting 100 mgd of water — with the advent of the holy month of Ramazan.
The weekly water-holiday system, which had been introduced in October 2002 in the Indus-fed localities in order to divert the conserved quantity to the Hub-fed localities, is also expected to be done away with.
Restoration of 100 mgd supply coupled with the abolition of water holiday system would definitely improve supply position considerably, not only in the areas hooked to the Hub source — Orangi, Baldia, North Karachi, Surjani, Shershah and Site, Mianwali Colony, Saeedabad, etc. — but also in the areas receiving water from Indus source, the sources pointed out.
The other works which are to be undertaken during the water suspension period include repairing of rusted aqua-ducts of Wapda’s main canal and Karachi Supply Canal, lining of block masonry works, strengthening of pipelines from Hub pumping station to the 200-feet-high rising main, and plugging of leakages in three major pipelines of 66, 48 and 54 inch dia pipelines.