Ground water and contaminant flow modelling in Bremen area

Seminar paper from the year 2015 in the subject Geography / Earth Science - Miscellaneous, grade: 1.0, Technical University of Darmstadt (Fachbereich Geologie), course: Arbeit im Rahmen des MSc TropHEE, language: English, abstract: In the northern german lowlands north west of Bremen and south west of river Weser a factory wants to extract 70 cubic meters of groundwater per hour. They want to pump clean water despite of a landfill as contaminant source south of the well (=upstream of the ground water flow). The well is very close to the western one of two parallel faults within the middle layer, with conductivities between 1 and 1E-9 m/s and is strongly influenced by them. The uppermost layer (= Saale) has the highest conductivity and is therefore most important for the flow regime. A MODFLOW model with 3 layers, given elevations and heads in the river and in the rim of the area was run many times to check if and how the well can can deliver the 70 cubic meters per hour of clean water.

Lowering pumping rate, displacement of the well away from the fault, is only sufficient for the case of low conductivity (closed) faults. For open (high conductivity) faults these measures are not sufficient and a cleaning well north of the landfill is necessary. By trying lower and lower pumping rates of the cleaning well the minimum extraction rate for the cleaning well was found.