Most of the storm water drains in Karachi have been encroached with illegally constructed houses, shops and other structures, according to a survey made by government departments. These encroachments have pivotal role in impeding free flow of the rainwater causing urban flooding and immense damage to the city, in case of a catastrophic spell of rainfall, like the one recently hit the port city. A survey conducted by Sindh Irrigation Department and the Karachi Metropolitan Corporation (KMC) few years ago pointed out thousands of built houses on GujjarNullah, stretched over a distance of 13.5 kilometers. According to survey papers several billions of rupees will be required to shift these houses and provide alternate homes to the affected people. According to the survey, 27 key water drains are occupied by the illegal encroachments with five to 80 percent occupation of the space, which are part of the natural drainage of the rainwater. “Shershahnullah from Lyari river to Urdu Bazaar, has been 80 percent encroached by various structures,” the survey report said. “SongalNullah another key drainage artery of the city at University Road, has been occupied by 70 percent,” the report said. “The space of City Nullah from Ranchhore Lane to Mai Kolachi has also been 70 pct encroached.” New Karachi’s 9000 Road drain has been 60 percent encroached while, the area’s 7000 Road has also been 30 pct occupied with illegal structures. Moreover, the space of Pehlwan Goth nullah and LyariHaroonabadnullah have been encroached by 30 percent. According to KMC officials, the survey was dispatched to Sindh government with recommendations. The encroachments have further increased from the time of the survey till now, they said. An anti-encroachment drive was launched in GujjarNullah, in which a few thousands of encroachments were demolished, officials said.