Transport of Particle-Bound Contaminants in the Middle Elbe River
Sediment-sorbed concentrations of HCB significantly exceed environmental quality criteria and the Elbe River Community (FGG Elbe) has stated that a reduction of 98 % of the sediment-bound HCB load (relative to 2006) would be necessary to achieve all management objectives (FGG Elbe, 2009). To better understand the fate and transport of cohesive sediments and sediment-sorbed HCB, a hydrodynamic and sediment transport model for the reach of the Elbe River basin between Dresden and Magdeburg was developed. An evaluation of impact of the numerous groynes, or spit dykes, along the Elbe, was integrated into the modeling effort.
The impact analysis of Elbe groyne fields showed that they reduce transport times of cohesive material and associated sediment sorbed contaminants approximately 15 % during average hydrodynamic conditions. The quasi 2D model was run under a variety of discharge scenarios to calculate the extent of transport of sediment and sediment-bound HCB to the floodplains (337 km2) between Torgau and Magdeburg during nine high water events exceeding mean high discharge (MHQ) between 1998 and 2011. Results for sediment and HCB accumulation on floodplains are presented and discussed. A discussion of uncertainty and issues in model development is included. In addition, ample evidence that extreme high water events, such as the August, 2002 floods can have long-term implications on the suspended sediment transport regime and contaminant loads is provided.
A worst case analysis of HCB uptake by dairy cows and beef cattle indicate that significant, biologically relevant quantities of sediment-sorbed HCB accumulate on the Elbe floodplains following flood events. Given both the recent high frequency of floods in the Elbe Basin, and the potential increase in flood frequency due to climate change, an evaluation of source control measures and/or additional monitoring of floodplain soils and grasses is recommended.
Funded by: Bundesanstalt für Gewässerkunde, Koblenz
Project duration: 2009-2013
Coordinators: Dr. Peter Heininger (BfG), Dr. Daniel Schwandt (BfG), Prof. Susanne Heise
Team Members: Dr. Kari Moshenberg
Moshenberg, K., Calmano, W. & Heise, S.: Fate and Transport of Cohesive Sediment and HCB in the Middle Elbe River Basin. Vortrag, EGU, Wien 2014 (Abstract)