Managed Aquifer Recharge: Bridging Climate Change, Water Security, and Ecosystem Conservation

In a context of intensified pressures on the groundwater resource, managed aquifer recharge (MAR) has emerged as a strategic mean to enhance water security and strengthen the resilience of groundwater systems under changing climatic conditions. MAR encompasses a range of techniques for intentionally enhancing aquifer recharge using various kind of source water through infiltration basins, injection wells, induced riverbank filtration, and other engineered systems. When appropriately designed and operated, MAR can maintain groundwater levels, increasing storage, improve water quality, mitigate land subsidence, combat seawater encroachment in coastal aquifers, and sustain groundwater-dependent ecosystems. These often multifunctional benefits position MAR at the interface between climate change adaptation, integrated water resources management, and ecosystem conservation.

Still several issues prevent MAR systems to be adopted at full scale. Among the most relevant, governance and regulatory barriers discourage investment and slow project approval and scaling. MAR projects often fall between surface water and groundwater regulatory frameworks, leading to unclear institutional responsibility. Permitting/authorisation processes are frequently complex, fragmented, poorly aligned with MAR practices, or lacking. Even if MAR construction costs are relatively low, compared to traditional water infrastructures, the benefits deriving from MAR are less visible and often long-term. Furthermore, the lack of funding mechanisms, especially in Europe, limits expansion beyond pilot or demonstration projects. Concerns persist around risks such as groundwater contamination, and even in cases when risks are technically manageable (as for many other types of waterworks), these perceived risks remain a major obstacle to large-scale adoption. Finally, social acceptance and stakeholder understanding of MAR is often low, particularly when reclaimed water is proposed for recharge.

On the other hand, recent years have seen a surge in pilot and demonstration schemes and the regulatory point view started gaining attention. Moreover, the need for low-carbon and low-cost solutions may sustain the widespread adoption of MAR schemes. Two more elements may drive the change. The first one is the likely possibility that MAR qualifies as a nature-based solution. Yet, many MAR schemes mimic natural processes to enhance recharge. However, the debated question now relates to the fact whether MAR infrastructures may directly provide net biodiversity gains. Achieving the biodiversity gain, thanks to the geoengineered infrastructure, by, i.e., supporting wetland ecosystems, providing more water to riverine ecosystems during period of low-flow, would constitute a positive value, and likely  position MAR waterworks in a prominent position respect to other options. Second, so called Agricultural-MAR may constitute a cornerstone for scaling up at watershed level. To this, significant discussion  and capacity building need to be set with the agricultural world. Relevant scientific questions need to be addressed, such as those related to potential aquifer contamination by nutrients and plant protection products/pesticides, and the impact on crops produced by the recharge techniques.

Advancing MAR from niche applications to a mainstream water management practice will require a shift from project-by-project implementation toward coordinated, cross-sectoral strategies. Embedding MAR within broader climate adaptation, land-use, and agricultural policies, while strengthening the science–policy interface, can help translate its conceptual potential into measurable and durable benefits.