JOIN USCAG report exposes fault lines in city’s underground utility mapping
An audit report by the Comptroller and Auditor General (CAG) of India has laid bare the fault lines in the underground utility mapping in Bengaluru, which often result in damages to utility lines and additional expense to the public exchequer.
The UDD and the BBMP — the authorities responsible for regulating the right of way of utility lines — were required to put in place policies/regulations to facilitate orderly laying of underground utilities and their mapping.
The BBMP, responsible for permissions for road-cutting and excavations in Bengaluru, established an online system in September 2015 — called the ‘Multi-Agency Road Cutting and Coordination System’ — for road-cutting permissions.
The CAG audit inspected the records of the UDD, BBMP, Bangalore Electricity Supply Company Limited (Bescom), Bangalore Water Supply and Sewerage Board (BWSSB), Karnataka Power Transmission Corporation Limited (KPTCL), Gas Authority of India Limited (GAIL), and GAIL Gas Ltd (GGL), between March 2019 and June 2021.
Inconsistency in maps
While GAIL and BWSSB had their assets fully mapped, Bescom and KSPTCL had mapped 83% and 88% of their networks, respectively.
However, the audit observed that the BWSSB had adopted old road shape files from 2002 for mapping its utilities. The time gap between the creation of road shape files resulted in a mismatch in the actual location of utilities.
This meant that in some cases, the underground water or sewage pipelines were shown overlapped on buildings, instead of roads.
The audit observed that the BWSSB’s GIS database did not capture the depth of the pipes below the ground level, pressure and flow direction. The GIS certificate, which was made mandatory for recording the completion of work, did not indicate the GIS coordinates or the details of other utilities.
Similarly, Bescom’s GIS maps were prepared in a two-dimensional format with only the length and size of underground (UG) cable, with no provision for capturing the depth at which the UG cable was laid.
The audit noticed that there was no system in place for data validation before certification. Data inconsistencies were observed in 84,916 out of 202,788 BWSSB records in the database.
Test verification
To physically verify the accuracy of maps of underground utilities, the audit collaborated with an IISc team to use Ground Penetrating Radar (GPR) technology in three chosen locations.
The studies done in Malleswaram Circle, Ideal Home Circle in Rajarajeswarinagar and Chandramouleshwar Temple Circle in Jayanagar showed many inaccuracies in the existence of water lines, such as the existence of one line instead of two, or line not being present, or the presence of an extra line.
The CAG report also notes that water and sewer lines were very closely laid in the surveyed locations contravening IRC norms and posing a risk of sewage mixing with potable water during the bursting of pipes.
Similarly, IRC standards suggested multi-utility ducts with separate enclosures for each type of service provider laying an underground cable network, which was not provided in the surveyed locations.
The audit observed that the incomplete GIS data on underground utilities resulted in frequent damages to the utility lines while carrying out road-cutting/excavation, and caused inconvenience to vehicular traffic. GGL pipelines suffered the maximum damage from BWSSB works (597) and by other external agencies (367). The report highlighted the lack of legal provisions to enforce mapping and inadequate coordination among the BBMP and the other bodies and suggested better coordination, data updating, etc, as remedial measures.