Integrated Assessment of Managed Aquifer Recharge (MAR) Techniques Combined with Water Reuse for Climate-Resilient Regional Water System

Future drying conditions accompanied by increasing water demand are putting groundwater systems under increased pressure. Managed aquifer recharge (MAR) techniques in combination with water reuse are approaches that are being considered to deal with water scarcity problems and promote circular economy goals. The State-of-the-Art (SOTA) - MAR assessments often focus on restoring groundwater levels and optimizing the efficiency of the MAR-system, which is often done using numerical flow and transport models. However, water reuse applications through MAR lie at the interface between anthropogenic and natural water systems, and need to be embedded within a regional strategy on water resources management . Therefore, focusing on feedbacks and interconnections within the whole system is necessary to identify possible consequences and trade-offs. A more holistic modelling representation, e.g. using system dynamics modeling, can better evaluate these complexities, rather than incorporating different models of the sub-systems into one. The latter adds more complexity and uncertainty to the modelling process, introduces boundary conditions issues, and requires higher computational demand. In this thesis, we aim to go beyond the SOTA to develop a modeling framework for combined hydrological and anthropogenic water systems, aiming to facilitate assessment of the propagation, benefits, and risks of water reuse through MAR practices taking into account future conditions. We intend to provide an integral vision of the water system and its internal interactions, overcoming the limitations of conventional modeling techniques. The ambition of this work is to investigate the gaps existing in such modeling frameworks and look into the applicability of data-driven approaches in combination with analytical/conceptual models to improve the representation of such a complex system, while providing interpretability for the model. The applicability of the model will be investigated based on a case study in Flanders, Belgium, where MAR approaches with reclaimed wastewater is being used to overcome the effects of drought on groundwater resources.