aiba Nazir, a teacher at a local university, says the commute from her residence in Model Town to her workplace has become an ordeal lately. The reason is this sinkhole she meets near Shadiwal Chowk on Main Boulevard, Johar Town.

The 10-15 feet wide and 15-20 feet deep sinkhole, which emerged recently, devoured a part of this busy thoroughfare, causing a nuisance for the commuters.

“Thankfully, it [the sinkhole] did not appear in the centre of the road, and there is still some space where you can bypass it,” Nazir adds. “Still, it costs you a lot of your precious time, especially during peak hours.”

The Water and Sanitation Authority woke up to the situation after a lapse of almost a week, and the sinkhole has now been covered with mud and soil. But it’s more of a temporary arrangement. Also, such occurrences aren’t rare. A florist who has a shop along the road, near the point where the depression was formed, recalls another, larger sinkhole on College Road, which had caused inconvenience to the traffic in Township and adjoining areas.

The flower vendor, who introduces himself as Shah, says that he shudders to think that his shop could be gutted in such an event.”

According to geologists, sinkholes are formed through a process called karstification in which soluble bedrock, such as limestone, is gradually dissolved by water. This dissolution occurs over time as acidic rainwater or groundwater percolates through the rock, eroding and creating voids. Eventually, the ground above these voids may collapse, forming a sinkhole.

Natural geological processes, such as the dissolution of carbonate rocks, contribute to the formation of sinkholes. Human activities, such as excessive groundwater pumping or construction practices, can accelerate the process. But the sinkhole in question was caused by leakage from rusty, underground water pipelines.

It’s no coincidence that in October last year the same road saw a deep depression, caused by a sewer line rupture. The situation forced the authorities to divert traffic to the service lanes between the LDA Complex and Shadiwal Chowk.

In July 2023, in Gowalmandi, a road which was under construction collapsed amidst a rainstorm. According to eyewitnesses, a car fell into the sinkhole thus created, and the driver suffered minor injuries. The district administration used a crane to pull out the vehicle and issued orders to cover the ditch after temporarily closing the road for traffic.

Perhaps, the most frighteningly abrupt sinkhole was created on Johar Town’s main boulevard on February 10, 2023, when a car fell into it. A 40-foot wide and 14-foot deep sinkhole was formed, apparently due to a sewer line rupture. Three members of a family who were in the car were badly injured.

Every time a sinkhole is created, the administration rushes to the site, cordons off the area, and fills the rupture. Every time, the culprit is the leakage of water from a 48-inch-diameter pipeline.

Natural geological processes, such as the dissolution of carbonate rocks, contribute to the formation of sinkholes. Human activities, such as excessive groundwater pumping or construction practices, can also accelerate the process.

ources say that WASA’s main sewer line, with a 26-inch diameter, laid some four decades ago, is in a dilapidated condition. The agency has submitted a summary to the caretaker chief minister of the Punjab, seeking Rs 1.3 billion to replace the sewer line from Shauq Chowk to the Shaukat Khanum intersection.

Work to plug the rupture, including earth-filling, compaction and asphalt laying, has started and is expected to be completed in a few days.

Ghufran Ahmed, the WASA managing director, says there’s an urgent need for an overhaul and replacement of the sanitation and sewerage infrastructure in the city. In July last year, he says, he had forwarded a summary to the then chief minister, proposing the inclusion of the scheme, titled Replacement of Outlived Trunk Sewer from Shouq Chowk to Shaukat Khanum Main Khayaban-i-Firdousi, in the Annual Development Programme. Regrettably, this did not happen.

Explaining WASA’s role in such matters, Ahmed says the agency is responsible for the management, operation and maintenance of sewerage, water supply and drainage services in the city. It requires investment to replace the aging infrastructure periodically, adapting to the area’s evolving needs, he says.

As time passes, old sewers deteriorate due to corrosive gases in the sewage, leading to the weakening of the sewer crown (top). This weakening renders it unable to bear the traffic load, resulting in pavement failures. Sewer failures cause sudden settlements in the road above and can lead to fatal accidents.

The main trunk sewer at Khayaban-i-Firdousi, laid almost three decades ago, has deteriorated at various points resulting in frequent crown failures. The risk of crown failures increases during rains due to the erosion mechanism. The efficiency of a sewer line diminishes as it ages, causing surcharging of sewage in adjoining localities and overflowing in tail streets. In low-lying areas of Johar Town, this poses a serious public inconvenience, besides being a health hazard.

The current trunk sewer is inadequate for present needs and has exceeded its design period, necessitating immediate replacement to serve the area of Johar Town, especially A1, A2, A3, B, B1, B2, B3, D, D1, D2, E, E1, E2, F, F1, F2, R, R1, and R2 blocks; and the adjoining areas of Beher village. Ahmed says that a previous summary, initiated on August 25, 2020, seeking funds for replacement of the same sewer, was not entertained. The scheme was proposed for inclusion in the Annual Development Programme for the financial year 2022-23 but was not approved. Another summary, initiated by the WASA for the immediate replacement of the sewer, was presented in the third meeting of the caretaker Standing Committee of the Cabinet on Finance and Development on April 20, 2023. However, it did not receive approval, with the suggestion to include it in the following year’s ADP after fulfilling necessary legal and procedural requirements.

The WASA needs to replace the trunk sewer, 30 inches to 48 inches in diameter, measuring 4.5 kilometres. Although the agency has filled up the recent sinkhole, it has still to get the funds needed to replace the pipeline.

The writer is a media veteran interested in politics, consumer rights and entrepreneurship