Initial soil formation in an artificial river valley - Interplay of anthropogenic landscape shaping and fluvial dynamics

Abstract

Land rehabilitation is a strategy for restoring near-natural landscape systems in anthropogenically influenced environments. Especially in post-mining landscapes after open-pit mining, land rehabilitation gives opportunities and potential for near-natural landscape modeling. To evaluate its success, biological monitoring approaches with a focus on biodiversity are common. However, the loss of natural soils, which are the result of long-term formation, is an irreversible damage to the pedosphere. The natural soil functions must be completely re-established and it is difficult to examine its success.Our study area is located in the Inde River catchment (North Rhine-Westphalia, Western Germany), which is part of the international River Basin District Meuse. Due to the progress of the open-pit lignite mining, a 5 km long river course had to be relocated. To create a near-natural landscape and an appropriate development corridor for the river, a ~ 12 km long river relocation was designed. The artificial river section “Neue Inde” is still geomorphologically “naive” and characterized by temporary, highly energetic morphodynamic processes resulting in strong erosion processes in the river bed and the surrounding area. Our study investigated initial soil formation in a morphodynamically active artificial river valley, constructed with a restoration substrate called “Forstkies”.To characterize morphodynamics and to detect initial soil formation processes, we analyzed a transect of seven soil profiles. It includes floodplains and slope areas further away from the river. Allochthonous flood sediments can be differentiated from the underlying artificial restoration substrate by inherited enrichment of the pollutants Pb, Zn, and Cu. First initial post-sedimentary alterations are detected employing common soil parameters (grain size, CaCO3, total organic carbon and pH value) and geochemical weathering indices. The quality of the soils is appropriate to the state of development. The results obtained can be helpful for the planning of future restoration in post-mining landscapes.