goodwater

WP 16 aims at risk assessment and management of aquifer contamination in transition zones based on reactive transport modelling. Risk assessment and management of groundwater-river interactions has to be based on a contaminant mass flux approach because the impact of groundwater contamination on a river system can only be evaluated by comparison between river flow and groundwater discharge. Likewise, the impact on a groundwater abstraction well will depend on pumping rates and hydraulic aquifer properties. Such an approach requires flow models for the integrated system (groundwater/river; groundwater/abstraction well) as a basis. In order to evaluate abiotic and biotic processes involved in the fate of the pollutants, reactive transport models are needed that rationalize and integrate the most relevant processes influencing the fate of contaminants in aquifers. This includes advective/ dispersive transport, sorption and degradation, but also redox zonation. Model set-up and numerical issues are of particular interest, as the hydraulic and vertical gradients may be steep; further, dynamic stressing model discrimination, boundary conditions and efficient transient model codes. The models will be developed and implemented by fellow 16 (SV: H.J. Albrechtsen/ P.L. Bjerg, DTU). Data input will be provided in close collaboration with the more process oriented fellows. Fellow 7 (HMGU), 10 (DTU), and 13 (K.U.Leuven) will provide input regarding chlorinated hydrocarbons - especially related to groundwater–surface water-interfaces. Fellow 7 (HMGU), 13 (K.U.Leuven), and 15 (DTU) will provide input regarding pesticides - especially related to transition zones in drinking well abstraction zones. In addition, data obtained in model aquifers and field stable isotope data can be interpreted more comprehensively by reactive solute transport modelling, as foreseen in interactions with fellows 2, 3 (GEUS), and 11 (HMGU). Furthermore, generic information from the mesocosm ecosystem at HMGU can support the development of the architecture of the models. The models will also identify knowledge gaps, and thus interact with the planning of the laboratory experiments and field investigations Access to monitoring data and field locations will be provided to fellow 16 by the Miljøcenter Odense (G. Larsen), which will in addition be involved in co-supervision of fellow 16 through at least 3 meetings over the whole training period. An introduction into an engineering company by e.g. field work (sampling, drilling), risk assessment, and application of numerical models will be provided by Orbicon (H. Møller-Jensen) for fellow 16 over a total period of 1 month.