Groundwater systems are under enormous hazards in urban areas. Urbanization influences the behavior and compositions of the subsurface system. This leads to adverse hydrological, aquifer quality and socio-economic effects which compromise sustainability. The European Environmental Agency (EEA) estimates a number of 100,000 polluted sites in European countries, many of them contaminated with chlorinated hydrocarbons (EEA 2005). To reduce these impacts, an application of a groundwater risk assessment management is essential. The present dissertation contains a contribution to groundwater risk identification of an urban aquifer contaminated with chlorinated ethenes, which dischares to adjacent hydrosystems. In this process, the hydrodynamic impact on a regional chlorinated ethenes dispersal of an urban groundwater and surface water system is quantified. The aim is a determination of spatial probability of concentration occurrences isolines (spcois) on a regional scale under average and extreme conditions. The computation of the spcois is based on steady-state and transient 3D multi-species transport simulations of an unconfined aquifer. For solving the formulated problem, an aquifer reconstruction by coupling of conventional and geo-stochastic simulations were performed to estimate parameter uncertainties. Furthermore, a Direct push technique was applied for a downscale part of the model domain to evaluate the implemented hydraulic parameters of the reconstructed subsurface model. A hydrograph analysis was performed to identify appropriate initial and boundary conditions. The calibrated multi-species transport model was subjected to a Monte Carlo simulation. Seven flow and transport-relevant parameters were ranged n-times from a probability distribution to compute spcoi of the contaminated site. The thesis shows that hydrodynamics represent a crucial risk factor in the field of urban groundwater risk identification. Especially, the pollutant dispersal pattern is affected spatially and temporally. Even through the Monte Carlo approach, a future pollutant passage into the adjacent ecosystems could be identified including its occurrence probabilities. The PhD research is assigned to a source-pathway-receptor approach according to McKnight et al. (2010). Indeed, this approach contains a 3D multi-species transport model including different hydrological dynamics. This approach was implemented in cooperation within the framework of the International Graduate College 802 “Risk Management of Natural and Civilization Hazards on Buildings and Infrastructure”.


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    Title :

    Numerical stochastic simulation for remedial activities and risk assessment of an urban groundwater system


    Additional title:

    Numerische-stochastische Simulationen für Sanierungsmaßnahmen und Risikobetrachtungen eines urbanen Grundwasserleiters


    Contributors:

    Publication date :

    2011



    Type of media :

    Miscellaneous


    Type of material :

    Electronic Resource


    Language :

    English


    Classification :

    DDC:    627