Mumbai: MRVC builds waterproof subway in Bhiwandi to tackle monsoon flooding

In a firstofitskind engineering project Bhiwandi is set to get a scientifically designed ldquowaterproofrdquo subway aimed at preventing monsoon flooding a chronic problem in underpasses across the Mumbai Metropolitan Region MMRThe pedestrian subway being constructed by the Mumbai Railway Vikas Corporation MRVC beneath seven railway lines is in the final stages of completion and is expected to be tested during the upcoming monsoonOfficials said the underpass has been specifically designed to prevent water seepage and waterlogging even during heavy rainfallWhy flooded occursOfficials said most subway flooding occurs when heavy rainfall raises the surrounding groundwater table allowing water to seep into the structure from below and the sides Surface runoff from roads also enters lowlying underpasses during heavy rain The Bhiwandi design attempts to address both issues simultaneouslyOfficial sayslsquoWe have designed the lowheight waterloggingproof subway which will be free of waterlogging in the monsoon It is a brownfield project and is being done at Bhiwandi passing under seven railway lines mdash those belonging to Indian Railways on the DivaVasai main line and the other two of the Dedicated Freight Corridor The design has been studied and is now in the final stages of implementation We intend to complete it before the monsoon sets in which will be the final test of the design Boxes have been pushed under the rail lines and the subway is getting ready It will be a pedestrian subway but it will allow twowheelers and bicycles No threewheelers or vehicles will be able to use itrsquoHow the waterproofing system worksThe waterproof subway is being constructed beneath seven railway tracks in Bhiwandi It is designed to prevent monsoon flooding and water seepage PicBy Special ArrangementInterlocked concrete structuregtgt Concrete boxes are connected using a ldquocupandconerdquo interlocking system similar to tongueandgroove jointsgtgt Officials said this reduces the possibility of water entering through structural gapsSpecialised rubber gasketsgtgt The concrete boxes are wrapped with engineered rubber gasketsgtgt These are designed to withstand pressure and prevent seepage under varying environmental conditionsDual protection membranegtgt The structure includes a System Dual Protection SDP membranegtgt Officials described it as a highperformance waterproof barrier technologyChemical void sealinggtgt Chemicals are used to fill microscopic gaps and voids in the structuregtgt This provides an additional layer of seepage protectionRaised entry pointsgtgt The subway entrances are constructed at a higher level than the adjoining roadgtgt This is intended to stop rainwater from flowing directly into the underpassProject at a glanceFeature DetailsLocation BhiwandiAgency Mumbai Railway Vikas CorporationType Pedestrian subwayRailway lines crossed SevenIncludes DivaVasai line and Dedicated Freight Corridor linesAllowed users Pedestrians bicycles twowheelersNot allowed Threewheelers and larger vehiclesCurrent status Final stages of construction Why underpasses get floodedOfficials said most subway flooding occurs when heavy rainfall raises the surrounding groundwater table allowing water to seep into the structure from below and the sides Surface runoff from roads also enters lowlying underpasses during heavy rain The Bhiwandi design attempts to address both issues simultaneously