Environmental impact assessment of a METRO infrastructure facility construction by modelling water and soil pollution

Abstract

The construction of large infrastructure projects such as highways, railroads, landfills, airports, harbours offers great social-economic opportunities for the development of a region; it is also mainly responsible for the deterioration of natural environment in the greater areas where these projects are located. The goal of environmental impact assessment (EIA) that is carried out before the construction of such a project is to propose measures and actions that will limit negative environmental impacts during its construction and operation phases. The common perception is that large scale infrastructure projects can only damage natural environment even though very strict environmental requirements are imposed by the Authorities. This was not the case in Eleonas Attikis region in Greece where METRO facilities were built. During the construction phase, hazardous solid wastes were found buried in the urban area where METRO facilities (station, tunnel and depot) were located, raising serious environmental issues in natural and human environment in the region.The protection and restoration of environment in an uncontrolled waste dumpsite require accurate estimation of subsurface pollution extent and intensity. The scope of the present analysis is to map the contamination in the aquifer of Eleona Attikis where METRO facilities (station, tunnel and depot) were built. Numerical modelling approaches were used to estimate environmental impacts of this project to soil and water resources in the greater region. The results have shown that the removal of buried solid wastes to construct METRO station and depot was crucial in order to eliminate negative impacts in soil and subsurface water resources. An impact assessment of hazardous solid wastes buried for many years in the aquifer was also performed. The findings of this analysis proved that the implementation of a large infrastructure project such as the one in Eleona Attikis Greece was environmentally beneficial for the region.