PhD Defense | Min Lu | Multi-method assessment of river-aquifer interactions in lowland floodplains across spatial scales

Multi-method assessment of river-aquifer interactions in lowland floodplains across spatial scales

Lowland rivers and shallow aquifers are closely coupled. They exchange water, solute and heat across the interface through physical, chemical and biological processes. The interactions are highly dynamic and the driving mechanisms are complex. Understanding river–groundwater interactions is of crucial importance and can provide insights and assistance for future environmental management decisions to maintain a healthy hydro-ecological balance. 

To improve our understanding about the hydrological processes between rivers and aquifers, and explore the dynamic variations of the exchange fluxes between them, this PhD research proposes a multi-method approach covering different spatial and temporal scales. The applied approaches include baseflow separation, impulse response modeling, time series analysis, streambed temperature profiling, water sampling, hydraulic gradient measurements, thermal infrared imagery, and process modeling of the unsaturated and saturated zones, and also several innovative methodologies for data interpretation and analysis. 

Through the application of different methods, this series of studies (1) have identified hotspots of groundwater inflow to rivers locally, (2) have revealed and quantified the spatial and temporal dynamics of the exchanger fluxes at nested scales (point, segment, and catchment), and (3) have evaluated the hydrological processes and paths from precipitation, groundwater discharge, to streamflow in the three lowland catchments. It solves partly the scale challenges for studying such river-aquifer interactions. Recommendations and suggestions for further research have also been discussed. 

Promotor:

• Marijke Huysmans (KU Leuven)

SCK CEN mentors:

• Bart Rogiers
• Koen Beerten

Click here for a list of obtained PhD degrees.