- University of Potsdam, Institute of Environmental Science and Geography, Subsurface Hydrology, Potsdam-Golm, Germany (lena.scheiffele@uni-potsdam.de)
Brandenburg is one of the driest regions in Germany and heavily relies on groundwater resources for both drinking water supply and irrigated agriculture. The state is already experiencing declining groundwater levels, and climate change is expected to further exacerbate the situation. For sustainable management of groundwater resources, the groundwater recharge rate is a key parameter. However, its quantification remains a challenge since it cannot be directly measured at the field scale.
In this study, we utilize daily data from multiple cosmic-ray neutron sensors (CRNS), which enable non-invasive measurement of soil moisture in the near-surface root zone on a hectare scale to calibrate a soil hydrological model (HYDRUS-1D) and derive downward water flows below the root zone as an approximation of groundwater recharge.
For this purpose, we use a unique dataset collected over more than five years at a highly instrumented agricultural research site near Potsdam, Brandenburg. The ~10 ha site, featuring a variety of agricultural plots, extends along a gentle hillslope towards a lake above a Pleistocene, unconfined aquifer with a groundwater table depth ranging from 1 to 10 meters. Core of the instrumentation is a cluster of eight continuously operated CRNS combined with more than 25 point-scale soil moisture profile probes measuring to depths of up to 1 m. A wide range of additional measurements, including soil texture, hydraulic properties, continuous soil moisture measurements at depth, and groundwater level monitoring, provide a robust foundation for validating the model and capturing the relevant hydrological processes at the site.
In various simulation experiments, we evaluate the added value of using different soil moisture products for model calibration. To evaluate long-term trends and variability in groundwater recharge, we run the calibrated model with over 50 years of historical weather data. We analyze changes in groundwater recharge rates under varying climatic conditions and discuss the associated uncertainties, particularly in the context of the site’s tight water balance.
How to cite: Scheiffele, L., Dimitrova Petrova, K., Munz, M., Francke, T., Heistermann, M., Marret-Sicard, E., and Oswald, S.: Advancing groundwater recharge estimation at the field scale: spatiotemporal dynamics of soil moisture and simulated 1D water fluxes at a cosmic-ray neutron sensing cluster site in northeast Germany, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17305, https://doi.org/10.5194/egusphere-egu25-17305, 2025.
