GE 3: Bremen Dam: effects of a dam on the surrounding groundwater
Responsible beneficiary: GDfB
The aim of this project is to better understand the effects connected of a river-dam construction on the groundwater in the surrounding aquifers. In Bremen the naturally receiving stream “Weser” flows through glaciogenic quaternary sediments, which are typical for the continental neighboring countries of the north sea. The river is backed up in order to the production of electric power. The resulting rising groundwater upstream of the dam site leads to an intrusion of salty river into the aquifer. The river water bypasses the dam through the adjacent aquifer.
The shift of the dam by several hundred meters in recent years gives the opportunity to observe the changes of the flow regime. Salt of the river water and CHC from contaminated sites may be used as tracers.
The objectives are:
• Compile existing data on surface water flow and quality, groundwater level and quality, polluted sites a.s.o.
• Integrate compiled data into a 3D structural and hydrogeological model of the uppermost 30 m subsurface.
• Investigate tracer flow in the aquifer.
• Establish a detailed groundwater model with special focus on sensitivity of streamflow to changes in riverwater head.
• Identify methods of preventing possible undesirably effects on the groundwater flow due to dam construction
• Collect and imply transnational knowledge about groundwater management connected with dam construction (NL, D, B)
Stakeholders are municipality, local groundwater extracting companies, environmental authority