Numerical modeling of heavily polluted fine-grained sediments remobilization in northern Czech Republic
Abstract
The northern part of the Czech Republic is regarded as significantly polluted by antecedent or ongoing heavy industrial production mainly concentrated in the riparian zones of the Elbe River and its tributaries. Toxic pollutants tend to persist in the environment for a long time bound with fine-grained sediments.
Nevertheless, a high-flow event can induce a remobilization of those deposits and lead to secondary pollution of downstream aquatic ecosystems. Numerical modeling was used as a tool for remobilization probability assessment under local hydrodynamic conditions within 113 km of Elbe and Bílina river beds and riparian zones.
The assessment was based on statistical evaluation of causal discharge at the time of remobilization defined as significant erosion of observed sediment depositions. MIKE modeling software by DHI was used with different levels of horizontal plan schematization according to flow conditions and available data sources.
Sediment transport was calculated simultaneously with hydrodynamic simulation of the unsteady synthetic boundary conditions based on observed flood properties. The study contributes to risk-based assessment of polluted sediment management of the Elbe and extends the current scope of remobilization prediction within a reasonable timeframe using a numerical modeling method.