LAHORE: The officials of the Lahore Development Authority (LDA) blame the flawed design and leakage in the Water and Sanitation Agency (Wasa) sewer line running between Johar Town`s main boulevard Khyaban-i-Firdausi and Khyaban-i-Jinnah for the repeated emergence of sinkholes on the roads.

Two large sinkholes have appeared on Khyaban-i-Firdausi, the portion of the road leading from Allah Hu Chowk to Shaukat Khanum Hospital, after heavy rains in the city last week. Luckily, no casualty or loss of property was caused.

A deep sinkhole had opened up near the Shadiwal Chowk on Feb 9 earlier this year, purportedly due to the rupture of a 40-year-old trunk sewer. Then three members of a family were injured when their car fell into the 40-foot wide and 14-foot deep hole. The district administration had ordered an investigation into the accumulation of sewage in the adjacent greenbelt over the last few days, allegedly due to a leak in the 48-inch-diameter pipeline. It took weeks for the LDA to plug the rupture, which included earth-filling, compaction and laying asphalt.

No results of the inquiry have sofar been made public.

In August 2020, another sinkhole hadappearedontheroad.

Experts say depressions in a road`s infrastructure happen if water enters underground and causes erosion. It may also happen if there is improper or substandard earth-filling, compaction, or asphalt-laying work.

A sinkhole or depression means the surface of the ground is no longer supported and during rains when the asphalt layer gets weak or if any heavy vehicle speedily passes by it causes the `hollow road surface` to sink down.

A former officer in the LDA engineering department says the whole main boulevard needs to be thoroughly studied for faults in design, particularly leakage of the sewer line running beneath the road.

Requesting not to be named, he says the greenbelt along the road also requires to be taken care of as it remains submerged by the rainwater for longer periods, absorbing too much quantity of water and allowing itsseepagebeneaththeroad.

LDA Director General Aamir Ahmad Khan, after the February 2023 sinkhole, had claimed that theinitial inquiry found a rupture in the sewer line due to the accumulation of gas inside as the cause of the incident.

A spokesperson for Wasa says last year they had submitted to the Punjab government a plan for the replacement of the sewer line (from Allah Hu Chowk to Shaukat Khanum Chowk) but could not get approval for it. The plan was again submitted for inclusion in the ADP for the financial year that ended on June 30 but to no avail, he says, adding their efforts for this project in the supplementary budget also did not bear fruit. He admits that the sewer line needs immediate replacement but it is only possible with the provision of funds.

Up to 10 sinkholes have appeared in Lahore in the last five years and two of them on Khayaban-iFirdausi. A deep crater had appeared near the GPO Chowk on The Mall in July 2018 after the rainwater eroded the earth underneath it, causing a massive damage to the structure of an underground Orange Line train station.

The same month, another sinkhole had emerged on Gulshan-i-Ravi main road reportedly due to a leaking trunk sewer. Staff Reporter