Aquanty
HGS RESEARCH HIGHLIGHT – Quantifying the effect of managed aquifer recharge on the hydrologic resilience of coupled surface-groundwater systems in northeast Germany
Stautzebach, J., Steidl, J., & Merz, C. (2026). Quantifying the effect of managed aquifer recharge on the hydrologic resilience of coupled surface-groundwater systems in northeast Germany. Journal of Hydrology: Regional Studies, 66, 103533. doi.org/10.1016/j.ejrh.2026.103533
“To derive the full degree of interaction among domains, the surface water groundwater modelling software HydroGeoSphere (HGS) (Aquanty, 2025) was used. In contrast to comparable groundwater models (e.g., MODFLOW), this code solves the governing flow equations not only for saturated and unsaturated conditions but also for surface runoff, thereby enabling a fully coupled representation of surface–subsurface hydrodynamics (Fig. 3)”— Stautzebach, J. et al., 2026
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♦Graphical Abstract
We're pleased to highlight this publication by Jan Stautzebach, Jörg Steidl, and Christoph Merz, which investigates how managed aquifer recharge (MAR) can improve the resilience of coupled surface water–groundwater systems under changing climate conditions. Using HydroGeoSphere (HGS), the researchers evaluated how surplus streamflow can be redirected into natural infiltration basins to replenish groundwater, stabilize connected streams, and strengthen regional water resources in northeast Germany.
Declining groundwater levels, prolonged droughts, and increasingly variable precipitation are placing growing pressure on groundwater and surface water resources across many regions. Traditional water management approaches often focus on either groundwater or surface water independently, making it difficult to evaluate the complex interactions between the two systems. Managed aquifer recharge has emerged as a promising climate adaptation strategy, but accurately assessing its long-term impacts requires fully integrated hydrologic models capable of simulating groundwater flow, surface water dynamics, evapotranspiration, and recharge simultaneously. This study addresses that challenge by using HydroGeoSphere to quantify both the local and regional benefits of MAR over a 30-year simulation period.
♦Fig 3. Conceptual illustration of the MAR simulations with governing eco-hydrologic processes, parameters, and stream and groundwater heads specified as 1. order boundaries of the HGS model (also see Appendix 2, 5, 6).
The researchers developed a fully integrated HydroGeoSphere model representing a 4.5 km² forested and agricultural catchment within Brandenburg's lower Spree basin. The model simulated coupled saturated and unsaturated groundwater flow, surface runoff, stream-aquifer interactions, precipitation, and evapotranspiration while evaluating ten managed aquifer recharge scenarios using between 10% and 100% of available surplus streamflow. Natural topographic depressions were represented as infiltration basins where excess stream discharge could infiltrate into the shallow aquifer, allowing the researchers to track changes in groundwater recharge, groundwater levels, streamflow, and overall water storage throughout the watershed.
The simulations demonstrated that managed aquifer recharge can substantially improve groundwater availability while strengthening connected surface water systems. MAR increased groundwater levels by as much as 2 metres near recharge areas and produced measurable groundwater rises more than 900 metres away. The resulting increase in groundwater storage stabilized baseflow to connected streams, increasing streamflow by up to 15% during low-flow periods while maintaining only minor reductions during recharge events. The study also showed that natural topographic basins efficiently converted surplus streamflow into groundwater recharge, significantly improving recharge efficiency while minimizing evapotranspiration losses.
HydroGeoSphere was central to this research because it provided a fully integrated representation of the coupled surface water–groundwater system. Unlike conventional groundwater models, HGS simultaneously simulated saturated and unsaturated groundwater flow, overland flow, stream interactions, precipitation, evapotranspiration, and groundwater recharge, allowing the researchers to evaluate both the direct effects of managed aquifer recharge and the delayed feedbacks that occur throughout the broader hydrologic system. This integrated approach also enabled the team to identify potential side effects, such as localized groundwater flooding, highlighting the importance of comprehensive modelling when designing MAR projects.
This research demonstrates how HydroGeoSphere can support climate adaptation strategies by helping water managers evaluate the long-term benefits of managed aquifer recharge before implementation. By accurately capturing the complex interactions between groundwater, surface water, and climate, HGS enables practitioners to identify suitable recharge locations, optimize recharge volumes, and improve regional water resilience while protecting connected aquatic ecosystems. As droughts become more frequent and water resources face increasing pressure, integrated modelling approaches such as HydroGeoSphere provide a valuable tool for developing sustainable groundwater management solutions.
Abstract:
Study region
A mixed forested/ agricultural area within Brandenburg’s lower Spree catchment, northeast Germany.
Study focus
This study examines the potential of managed aquifer recharge (MAR) to stabilize groundwater and connected surface water resources affected by climatic and anthropogenic impacts by reducing declines and overall variability. Utilizing an integrated surface water-groundwater model, the suitability of selected topographic basins was assessed in terms of their ability to recharge the underlying aquifer with surplus discharge water from local streams. After analyzing the aquifer’s response to increased groundwater recharge, the feedback of connected surface waters to the rise in groundwater levels was quantified and discussed in the context of regional adaptation strategies.
New hydrological insight
(1) It was determined that MAR operates efficiently with temporal surplus stream-discharge volumes to induce a significant increase in groundwater recharge and a resulting rise in the groundwater table of up to 2 m.
(2) Selected topographic natural small basins were verified as efficient locations to recharge an unconfined aquifer via percolation and may be applied in greater number to strengthen the regional aquifer system.
(3) The increase in groundwater levels over longer distances (> 900 m) enables the stabilization of the base flow of connected surface waters and strengthens water related ecosystems via an increase in flow volume by up to 15%.
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