Mumbai Coastal Road leakage is ‘normal, limited issue’

After leakages appeared at various spots inside the Coastal Road tunnel the BMC repaired them on a war footing and on Thursday there were no active spots inside the southbound tunnel ldquoSuch leakages at the expansion joints may appear in the future due to geological changes They were not due to structural flaws and we will form a strategy to deal with themrdquo the BMC saidMIDDAYS February report reviewed city tunnels after Delhis Pragati Maidan tunnel faced water logging issues prompting closures for repairs At the time BMC officials assured they tackled leakage in Mumbai Coastal Roads twin tunnels using a fourlayer barrier An official said To make the tunnels leakagefree we carried out works like primary grouting or filling the gap between the segmental lining and the excavation surface with cement material secondary grouting or cavity filling where the primary grouting was incomplete using EPDM gaskets to create a watertight system between segment rings and hydrophilic cord which is expandablerdquo claimed an official from the Coastal Road ProjectLeakages inside the tunnel have now been fixed by BMC PicsKirti Surve ParadeBut even after that leakages started from a few points inside the tunnel last week After CM Eknath Shinde visited the spot he assured action to monitor and close all 25 points in both tunnels Now the BMC officials said ldquoSuch issues happened due to geological factors and they are lsquonormalrsquo All over the world tunnels are not 100 per cent leakageproof It is due to geological movement tides and other factors affecting the tunnels There should be constant observation and finding solutions to tackle the pointsAn official further explained that the issue at Pragati Maidan was different The tunnel there is under the mainland and floods every monsoon whereas the twin tunnels of the Coastal Road are 15 to 20 metres underground in an intertidal zonemdashwithin the high and low tide areamdashwhich is constantly impacted by waves In this particular leakage there is constant vehicular movement over the tunnels which might have caused expansion in the joints After the leakage was pointed out they treated five joints where it occurred ldquoOut of 25 points five points in a stretch of 200 metres near Bal Bhavan leaked But we will map all 25 points in both tunnels and form a strategy with other experts to tackle such issues in the futurerdquo said an officialThe 1058km Coastal Road is being constructed from the Princess Street flyover at Marine Drive to the southern end of Bandra Worli Sea Link Twin tunnels have been built at a depth of 12 to 67 metres under Malabar Hill Each tunnel is 1219 metres in diameter The southbound tunnel has already started and the northbound tunnel is supposed to start by June 10Pragati Maidan issueThe Pragati Maidan complex including a 13 km tunnel and five underpasses opened in June 2022 It has faced waterlogging and seepage issues causing several shutdowns for repairs The Delhi PWD issued a showcause notice to the contractor for serious technical and design deficiencies These issues have raised concerns about the safety of similar projects in Mumbai such as the Mumbai Metro Line 3 and Coastal Road and other projects which are nearing completionJune 10Day northbound tunnel is expected to start