Pilot area
Stuttgart, the capital of Baden-Württemberg state, is located in the center of a densely populated region in south-western Germany. The FOKS project area of 533 ha is situated in the north of the city centre, in the valley of the Feuerbach River, a tributary of the Neckar River.
Aerial Photo of Feuerbach
Long industrial history
As many districts of Stuttgart, the district of Feuerbach is constricted by severe soil and groundwater contamination generated over decades of industrial and commercial use. Due to the structural change many former industrial sites now are converted into service and residential use. Numerous single site investigation and remediation activities took place in Feuerbach have been carried out since 1984. Thus 300 contaminated sites were identified. 193 of them are polluting or potentially polluting the groundwater by chlorinated hydrocarbons (CHC), which are known to generate long plumes.
Complex hydro geological conditions
Due to the neighbouring sources and overlapping of different plumes the identification of the liable polluters is a challenging task. Additionally the allocation of the groundwater damages is impeded by the complex hydro-geological conditions in the project area. The hydrology is engraved in the stratum of the Middle Neuper which is composed of numerous layers of mudstone with gypsum deposits Gypsum Keuper) and sandstones (Schilfsandstein). The solid rock layers are covered extensively by quaternary sediments which reach large thickness at slope base and in the plain tract. The investigation of singular contaminated sites has been inefficient in many cases due to the fact of the restricted view of consideration. Therefore the new integral groundwater investigation approach was applied during the project MAGIC (Management of Groundwater at Industrially Contaminated Sites) from 2005 to 2008.
Numerical transport and flow model
On the basis of a detailed data collection and data evaluation a hydro-geological model was developed of the project area. Together with about 200 additional samples of groundwater and geophysical information from 8 exploration wells a numerical transport and flow model was set-up. On the basis of 37 immission dumping tests the numerical model could be validated. The most significant plumes of CHC in groundwater as well as their related sources of pollution could be identified and mapped.
Picture of the numerical transport and flow model
Integral remediation plan
In FOKS the integral investigation started in Feuerbach during MAGIC will be completed. Natural attenuation processes and the sources with the highest emission of CHC will be investigated to clarify the pathways from the place of contamination to the deepest affected aquifer and along the contamination plume in the groundwater. Most important will be the integral remediation plan for the whole project area with focus on the hot spots which will be developed. Realistic remediation targets for sources and plumes will be defined.
