‘‘Nearly 220km of utility laying work was recently carried out in the NDMC areas using the trenchless technology. In this case, cavities remain open in the earth. With water seeping in, the road gets weak and eventually gives way,’’ said an official. ‘‘In trenchless technology, various agencies have to ensure they dig to an appropriate depth at least more than 1.5 meter to ensure they do not damage the sewer and drainage pipes. But this norm is flouted.’’
In August only, portions of Jaswant Singh Road, Kasturba Gandhi Marg, Rajesh Pilot Marg and Khan Market have caved-in. Explained NDMC spokesperson Anand Tiwari, ‘‘The road cave-in at Kasturba Gandhi Marg on Saturday was due to water seeping in through a cavity which was not filled up properly after a telecom company finished its work of laying wires there.’’
The other major reason for cave-in is the rotting drainage and sewer system, which dates back to the British times. According to NDMC officials, the sewer barrels in their area need to be restored immediately to avert a bigger disaster in the future. Said an official, ‘‘All the sewage barrels being encountered during construction work in CP are more than 60 years old and need to be replaced immediately. The drainage system is equally old.’’
Tiwari also blames cave-in incidents on depleting groundwater level in the area. Said Tiwari: ‘‘When it rains, the groundwater level suddenly rises and needs an outlet. This leads to the earth under the road giving way.’’
The story is similar in case of roads maintained by other agencies. Senior PWD engineers said that recently carried out utility pipeline laying work using trentchless technology was responsible for pavements and service roads caving in. ‘‘Racing against the Games deadline, utility providers took pipeline laying work on war footing. The work got completed just before the monsoon. When rain started, it caused problems,’’ said an official.
The official added poor maintenance of underground master drains, sewer and water pipelines cause more damage. ‘‘Maintenance of all such pipelines is vital. The cave-in incidents highlight how utility agencies have failed to maintain their service lines,’’ said the PWD official.
Officials added poor quality restoration of dug up stretches is also responsible for such mishaps. They admitted the agencies engaged in laying utilities simply fill the dug up portions in a haphazard manner, giving almost no time for the loose soil to settle.
One of the officials said earlier the projects requiring major digging used to take at least one year to complete. As an example he points to laying of pipelines for Sonia Vihar water plant. ‘‘But nowadays roads are cut and subsequently restored in 15 days. How can you except the soil to settle’’ asked the official.