Groundwater Vulnerability Assessment for Railroad Construction in Stockholm, Sweden, using Spatial Multi Criteria Analysis.

Abstract: The environmental impact of transportation construction, operation and maintenance is of critical importance. Therefore it is vital to carry out a groundwater vulnerability assessment for transportation projects at an early stage. The objective of the study was to apply a methodology for groundwater vulnerability assessment for transportation planning in order to identify and avoid areas susceptible to contamination. In this study a spatial multi criteria analysis (SMCA) was conducted where the impacts of railroads on groundwater were examined. Physical factors that influence the groundwater vulnerability such as infiltration capacity, hydraulic conductivity, effective porosity, slope, land cover, depth to groundwater and topographic wetness index (TWI) were considered in this study. Results from the study show that about 30% of the total area was prone to high and very high groundwater vulnerability. The final vulnerability map illustrated the highly vulnerable areas in the sand deposits and till and less vulnerable areas of rock outcrops and clay deposits. According to the outcome of the sensitivity analysis the methodology used in this study shows promising results and can be employed further with some improvements.