Managed Aquifer Recharge: Modeling approaches to integrated assessment of groundwater interventions

Groundwater resources are under increasing pressure due to water abstractions and climate change, leading to water scarcity problems and threats to groundwater-dependent ecosystems. Managed Aquifer Recharge (MAR) techniques offer a promising strategy for mitigating water scarcity problems and advancing sustainable management of groundwater resources. These measures aim at intentional recharge and storage of water in aquifers by linking periods of surplus with periods of shortage to overcome the temporal imbalance. While MAR has traditionally been implemented at local scales, growing challenges related to water scarcity and groundwater depletion have led to their increasing adoption across broader regions. This shift highlights the need for modeling approaches that can adequately represent MAR within regional water systems, emphasizing interactions with both hydrological and anthropogenic components while allowing investigation of trade-offs when planning these measures. This paper provides an overview of the modeling methodologies used to assess MAR interventions in a regional context. We begin by discussing the inherent complexity of the effects of groundwater interventions such as MAR at the regional level, particularly regarding water quantity. We then look into a range of modeling approaches available in the literature to capture these complexities, based on the modeling objective, data availability, and the required spatial and temporal scales. We further emphasize the importance of incorporating multiple levels of uncertainty throughout the planning and implementation of MAR projects and model-based analyses. Our study highlights that, despite their promise, integrated and holistic modeling approaches remain underutilized in groundwater research, including MAR, highlighting a need for broader development and adoption.