Morphodynamic conditions and distribution of trace elements at the mouth of the Nysa Kłodzka River into the Oder Valley deposits after flooding in 2024

Morphodynamic conditions and distribution of trace elements at the mouth of the Nysa Kłodzka River into the Oder Valley deposits after flooding in 2024

This thesis investigates the impact of the flood in September 2024 on the morphodynamics and the distribution of trace elements in the sediments at the confluence of the Nysa Kłodzka and Oder rivers. The study combined geological mapping, sediment sampling (112 samples from 56 locations), laboratory analyses (granulometry, organic matter, carbonates, and trace element concentrations, Fr/Al ratio) and statistical analysis (t-test, ANOVA, DCA, correlation matrices). The key findings indicate that the 2024 flood led to a significant increase in the concentrations of trace elements in surface sediments compared to deeper, pre-flood layers, highlighting the role of floods in contaminant mobilization and redistribution. Statistical analyses revealed a strong link between sediment composition, geomorphological forms, and distribution of elements. Significant spatial differentiation of metals was found between landforms, with the highest concentrations typically noted in oxbow lakes (for the Nysa Kłodzka river) and the youngest terrace IV (for the Oder river). The analysis against legal standards showed that the concentrations of arsenic, barium, and zinc in several sampling locations exceeded the permissible limits for residential areas. The study concludes that extreme flood events are a crucial mechanism for redistributing heavy metal pollution in river valleys. The results emphasise the need for integrated flood and pollution risk management strategies in this flood-risk area.