Padma Multipurpose Bridge Project

Annex 8-1ECP 4: Drainage ManagementProject Activity/Impact SourceExcavation andearth works, andconstruction yardsPonding of waterEnvironmental ImpactsLack of proper drainage forrainwater/liquid waste orwastewater owing to theconstruction activities harmsenvironment in terms of water andsoil contamination, and mosquitogrowth.Health hazards due to mosquitobreedingMitigation Measures/ Management GuidelinesThe Contractor shall Prepare a program for prevent/avoid standing waters, which CSC will verify in advanceand confirm during implementation Provide alternative drainage for rainwater if the construction works/earth-fillings cut theestablished drainage line Establish local drainage line with appropriate silt collector and silt screen for rainwater orwastewater connecting to the existing established drainage lines already there Rehabilitate road drainage structures immediately if damaged by contractors’ roadtransports. Build new drainage lines as appropriate and required for wastewater from constructionyards connecting to the available nearby recipient water bodies. Ensure wastewater qualityconforms to the relevant standards provided by DOE, before it being discharged into therecipient water bodies. Ensure the internal roads/hard surfaces in the construction yards/construction camps thatgenerate has storm water drainage to accommodate high runoff during downpour and thatthere is no stagnant water in the area at the end of the downpour. Construct wide drains instead of deep drains to avoid sand deposition in the drains thatrequire frequent cleaning. Provide appropriate silt collector and silt screen at the inlet and manholes and periodicallyclean the drainage system to avoid drainage congestion Protect natural slopes of drainage channels to ensure adequate storm water drains. Regularly inspect and maintain all drainage channels to assess and alleviate any drainagecongestion problem. Reduce infiltration of contaminated drainage through storm water management design Do not allow ponding of water especially near the waste storage areas and constructioncamps Discard all the storage containers that are capable of storing of water, after use or storethem in inverted positionPadma Multipurpose Bridge Design ProjectFinal Report (Environmental Action Plan)Environmental Impact Assessment Report A8-7June 7, 2010