ISLAMABAD: Compelled by the fast depletion of water resources in the capital, the Metropolitan Corporation Islamabad (MCI) has revived a decades-old plan of constructing some mini dams in the Margalla Hills to store water from the dozens of springs originating in the hilly range.
The plan is said to cost far less than the Rs50 billion required to complete the Ghazi Barotha Water Supply Project for bringing water from Tarbela.
MCI is also considering installing a Japanese technology for inflatable rubber dams, which has already been used in various countries including the US as they are inexpensive with a versatile structure capable of creating a pond or a flow in a particular watercourse.
“MCI has decided to conduct a survey before the installation of the dams after Eid,’ said Deputy Mayor Islamabad Syed Zeeshan Naqvi.
Mr Naqvi told Dawn studies conducted in the past were available but the corporation wants to conduct a fresh one to select the best points or natural ponds in the hills where the mini dams might be constructed.
Inflatable rubber dams, which are cheaper and have versatile structure, may be used
The deputy mayor said the issue of the damage to the environment of the hills has also been discussed and that the big fires that destroy the greenery in the hills may be controlled due to the dams.
Previous governments and city managers have been indecisive about how best to solve the water crisis in the capital.
The federal government in 2009 had scraped the Ghazi Barotha project due to reservations by some provinces which said their share of water from the Indus River will be consumed by Islamabad.
Since then, the Capital Development Authority (CDA) has not searched for other possible solutions except for launching awareness campaigns and threatening people of consequences if they waste water.
However, according to the CDA’s own data, some 60pc of the water is wasted before it reaches residents due to leaks in the rusty water supply lines. Islamabad is supplied with 60 million gallons a day (MGD) when it requires 110MGD.
According to a report, the idea of establishing mini dams was first discussed in the 90s. The idea was to store rain and stream water in the Margalla Hills as it is not used and just spills into the 18km Nullah Leh, which starts from I-9 and falls into the River Soan in Rawalpindi.
The construction of six mini dams will cost about Rs1 billion and they will help overcome the water shortage in the city for many years.
A retired CDA official said the authority had prepared a feasibility of the mini dam’s project and had sought financial and technical assistance from the Federal Flood Commission.
He said the master plan of the city also mentions that large ponds of water should be established at the foothills of the hills to store water in order to enhance the beauty of the area, raise the water table and help improve the efficiency of tubewells in the National Park area.
Some analysts say the problem of water shortage in Islamabad can be overcome if some necessary measures are taken including repairing leaks and replacing rusty and old pipelines, water metering and keeping an eye on the wastage of water in industries and commercial units including car wash centres and the construction of mini dams for storing rain and stream water.
Inflatable rubber dams
Inflatable rubber dams have been used as water control structures for more than 50 years. A rubber dam is a permanent structure comprised of a sheet of rubber-coated fabric which is fixed to a reinforced concrete foundation using clamp plates and anchor bolts. The rubber dam is inflated by pumping air or water inside the rubber body till the design height or pressure is reached.
Inflatable rubber dams have numerous advantages over other types of water control gate. They are simple and inexpensive operating systems, have relatively low capital cost, have perfect sealing and no leakage, are virtually maintenance free, have long spans of up to 100 metres, light structure and clean operation with no hydraulic oil required.
Published in Dawn, June 14th, 2018