Hidden water and landscape erosion

• Applicants: Dr. Michael Dietze; Professor Dr. Niels Hovius
• Subject Area: Physical Geography
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 530094161

Catastrophic floods and sustained droughts will be increasing according to the IPCC 2018 report. It is uncertain how this change will impact flow pathways and sediment yield within the watersheds of major rivers during hydrological extremes. A crucial element in the routing of discharge, and its erosive impact on landscapes, is subsurface storage of water and its pathways within the critical zone. While water in the subsurface will not directly contribute to local erosion, it will lead to a quick hydraulic response in the larger drainage network, with associated consequences on incision, bank erosion, and increased transport capacities. The challenge is in both observing and predicting change in subsurface water amounts and fluxes. We propose to explore this important hidden water compartment from two complementary sides: by spatially distributed measuring (overcoming limitations of current point-like measurements) and by landscape wide modelling (overcoming current model oversimplifications). Building upon existing infrastructure within the Eifel region, Germany, we plan to focus on a catchment within the upper Ahr valley, to understand how water storage and release in the critical zone impacts discharge and sediment transport. We will jointly survey groundwater and fluvial dynamics using passive seismology and water chemistry to build a picture of the subsurface flow paths and quantities. We will in parallel develop the methods to efficiently numerically model both the hydrology and sediment yield of the system. This research project will help improve flood anticipation, give insight into hydraulic breakpoints (initiation of overland flow and erosion), and understand future response in the critical zone due to climate change.

• DFG Programme: Research Grants
• International Connection: France
• Cooperation Partners: Professor Dr. Christoff Andermann; Dr. John J. Armitage