Regional modelling to forecast the transient chlorinated solvent risk to groundwater for water supply security

[摘要] The UK has an environmental legacy of chlorinated solvent contamination from historic industrial activity. Groundwater in Permo-Triassic Sandstone aquifers has been widely impacted. Future use of this resource requires methods to forecast regional-scale chlorinated solvent risk to groundwater assets. Current methods do not adequately represent chlorinated solvent dense non-aqueous phase liquid (DNAPL) source term behaviour and transient contaminant transport. This research investigates the hypothesis that improvements for regional contamination forecasting methods are possible and necessary. Experimentation with particle-based transport solutions shows that neglect of spatial dispersion is over-simplistic, especially where there are complex interactions between capture zones of different receptors. A fully dispersing Lagrangian solution, dynamic random walk (DRW), is developed that accurately models contaminant migration even with coarse-gridded flow models. For representation of the source term, a review of research into DNAPL behaviour is conducted. It is not feasible to derive a generic model for DNAPL dissolution into groundwater based on readily derived metrics at the regional scale. Therefore, a source term framework is developed that tests multiple conceptual models of DNAPL behaviour and therefore gives a holistic uncertainty analysis. Two case studies, based in historically industrial catchments in Birmingham and Stourbridge, validate the combined use of the DNAPL source term framework and the DRW transport solution. Chlorinated solvent sources are persistent, but careful asset planning informed by these regional risk modelling tools- DRW and the DNAPL source term framework -could allow continued use of solvent-impacted groundwater bodies.

[发布机构] University:University of Birmingham;Department:School of Geography, Earth and Environmental Sciences, Department of Earth and Environmental Sciences

[关键词] G Geography. Anthropology. Recreation;G Geography (General)