Towards an improved understanding of transport processes governing the spatiotemporal dynamics of particles and fecal bacteria in karst aquifers – IMPART

• Applicants: Professor Dr. Nico Goldscheider; Dr. Nadine Göppert
• Subject Area: Hydrogeology, Hydrology, Limnology, Urban Water Management, Water Chemistry, Integrated Water Resources Management
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 432288610

Groundwater from karst aquifer contributes substantially to water supply in many regions, cities and countries. Karst aquifers form by chemical dissolution in carbonate rocks and consist of a network of solutional conduits and caves embedded in the fissured rock matrix. They are generally characterized by high variability of water availability and quality. Contaminants, including fecal and pathogenic bacteria, can easily enter the underground through shallow soils, open fractures and via swallow holes. Inside the conduit network, they are rapidly transported over large distances and can reach wells or springs with limited attenuation. Therefore, the water quality at karst springs is often interrupted by short but severe contamination events. Suspended mineral particles and organic carbon play critical roles in the mobilization, transport and attenuation of fecal bacteria and other contaminants, but the precise processes and their spatial and temporal variability are far from being completely understood. The main goal of the proposed project is to achieve advanced insights into the transport processes governing the spatial and temporal dynamics of particles, organic matter and fecal bacteria in karst aquifer systems. The test site is a major karst spring and its catchment where two accessible caves make it possible to directly observe flow, water quality and transport processes inside the active conduit network. Relevant parameters include particle-size distribution, excitation-emission matrices for colored organic matter, enzyme activity of E. coli, fecal indicator bacteria, and total cell count using flow cytometry. Field work includes spatially-distributed sampling in the caves and at the spring; high-resolution monitoring at the spring during selected hydrologic events; and multi-tracer tests in the active conduit network, including comparative tests with solutes and particles. This experimental data will make it possible to achieve a better understanding of transport processes and microbial water quality dynamics of karst water resources, as a basis for an improved management of these valuable but vulnerable resources.

• DFG Programme: Research Grants
• Co-Investigator: Professorin Dr. Andrea Hartwig