The potential of localized near-nature managed aquifer recharge in the context of climate change adaption – An assessment within Brandenburg's lower spree catchment

Adaptation strategies are required to strengthen the resilience of groundwater resources that are primarily challenged by climatic and anthropogenic impacts. In this regard, active management through groundwater recharge and recovery techniques known as managed aquifer recharge (MAR) may stabilize groundwater storage and connected surface waters. One option for this management is the surface-induced recharge of available surplus water (infiltration basin), which seeps through the unsaturated soil zone, is stored in an evapotranspiration-free aquifer beneath it, and is recovered when needed. However, surface-induced MAR is underrepresented within the lower catchment of the river Spree. This study therefore assessed potential and individual recharge locations. Including thematic maps derived from a set of weighted criteria, a broad spectrum of suitable conditions were shown using indices in terms of land use, infiltration characteristics, hydrogeology, and economic feasibility. They were consistent with the recharge capabilities found for a dense network of natural topographic sinks, some of which can be employed for decentralized near-natural and semi-constructed groundwater recharge. Accordingly, surplus discharge water volumes from extreme weather events were assessed to be a sufficient source for many recharge locations, including those with storage capabilities that could be increased through construction. Altogether, around one quarter of the study area was found to be predominantly moderately to highly suitable, including some isolated and many closely spaced sinks of varying sizes, which can also be used for grouped groundwater recharge. These can therefore be regarded as scalable groundwater recharge clusters and are available for further comprehensive decision-making and model-based analysis. • Weighted criteria and thematic layers were used to execute a suitability analysis. • A potential map revealed locations for surface-induced groundwater recharge. • A dense net of topographic depressions was identified for near-nature recharge. • Constructive measures were outlined to enhance the natural potential. • Many recharge sites can be served with sufficient surplus surface water volumes.