Iron retention in Lusatia: a spatially differentiated analysis of the Spree

Abstract

Assessing the effects of the post-mining era on the water balance and quality of the Spree River proves challenging, especially in the context of climate change. The aim of this study was to better understand the complex interplay between surface and groundwater and particularly iron fluxes from groundwater into the Spree. Results from a controversial study from 2018 are compared with current developments in the Lausitz area. Based on a spatially distributed mass balance, the total amount of immobilized iron in the catchment is estimated to reach 30 tons per day. Besides the Spree (and its catchment) (39%), the mining pit lakes (24%) and the tributaries to the Spree (incl. their catchments) (34%) play a significant role in iron retention. The spatial distribution of groundwater inflows into the Spree, quantified using radon as a natural tracer, suggests preferential entries along the Spreewitzer Rinne, constituting up to 70% of the total inflow (139,800 m3/d).