Exploring Critical Zone Processes for Sustainable Water Management: The Case of Circus Lake Park, Bucharest

Urban areas face increasing environmental challenges from rapid urbanization, climate change and anthropogenic pressures. These disrupt natural hydrological cycles, leading to critical problems such as rise and fall groundwater levels with a series of chained consequences. Our study applies a critical urban zone approach (Bucharest district) to start within a framework of an accurate urban groundwater balance to analyze biophysical and chemical processes in the urban environment, focusing on the Circus Lake Park in Bucharest. The site presents a complex setting shaped by decades of anthropogenic alterations, including extensive excavation, infrastructure development, and impervious surfaces that disrupt natural hydrological processes. Climate-induced changes in precipitation patterns combined with the infrastructure modifications exacerbate these challenges, reducing groundwater recharge and lowering the lake levels. By incorporating alternative water resource (AWR) solutions, our study aims to establish sustainable water management strategies tailored to the existing urban ecosystem.

The methodology integrates field experiments, laboratory analysis, and hydrological modeling to address water scarcity and pollution challenges. Infiltration tests using several methods quantified the hydraulic conductivity of heterogeneous anthropogenic urban unsaturated zone. Chemical and biological analyses of water samples from rainfall, and street runoff assessed parameters such as dissolved oxygen, heavy metals, and nutrient concentrations. An experimental filtration system comprising sand, gravel, and activated charcoal layers was designed and tested to evaluate its efficacy in treating stormwater. Hydrological and hydrogeological models were developed to simulate rainfall, runoff, and infiltration processes, enabling the assessment of aquifer recharge potential.

The results underscore the value of the critical zone approach in addressing the multifaceted challenges of urban water management. The findings reveal the effectiveness of integrating scientific methodologies with practical interventions to mitigate the impacts of urbanization and climate change. Nature-based solutions, such as stormwater filtration and aquifer recharge, demonstrate their effectiveness in adapting urban ecosystems to these pressures. Circus Lake Park serves as a replicable model, providing a blueprint for cities around the world to implement sustainable water management strategies. Beyond technical interventions, this study emphasizes the importance of interdisciplinary collaboration and stakeholder involvement. Local authorities, water operators and community organizations were actively involved, ensuring that the proposed solutions align with social, economic and environmental priorities. This collaborative approach fosters wider acceptance and ensures long-term sustainability of interventions.

The research highlights the critical importance of integrating diverse scientific, technical, and social perspectives to advance urban sustainability frameworks. By linking theoretical insights with practical applications, this study demonstrates how critical zone processes can contribute to adaptive and efficient water resource management in urban contexts. Future research should focus on scaling these strategies and evaluating their long-term ecological and social impacts to further inform global urban resilience efforts.