Innovative Nature-Based Solutions for Urban Stormwater Management: Insights from Advanced Monitoring and Modelling Systems

Climate change and soil sealing are intensifying the challenges of urban stormwater management, driving the need for adaptive strategies to address evolving conditions [(Hou et al., 2020), (Hasankhan et al., 2024)]. Traditional grey infrastructures, designed exclusively to regulate rainwater flows, are monofunctional in nature. Their efficiency decreases as rainfall patterns shift leading to a greater risk of flooding. Furthermore, it does not address other urban challenges, such as the heat island effect (Menberg et al., 2013).

In response, nature-based solutions (NBS) such as rain gardens have emerged as promising alternatives. These structures help to alleviate flooding through sustainable practices. NBS also offer significant potential to create positive socio-cultural impacts by enhancing community engagement, fostering environmental stewardship, and integrating green infrastructure into urban lifestyles (De Knegt et al., 2024). However, although these systems are widely used, we still need to understand their long-term hydraulic performance under dynamic conditions (Wang et al., 2024). This research aims to address this gap by analysing the design, monitoring, and performance of a fully monitored rain garden system implemented on the campus of the Gembloux Agro-Bio Tech faculty of University of Liège in Belgium.

The system, spanning 4460 m², includes three swales and a semi-permanent retention basin. It is equipped with advanced sensors to monitor the dynamics of hydraulic flows, recording water levels (from 0.005 to 3.5 metres, ±2%) and flow rates (from 0 to 3.05 m/s, ±0.09%). These sensors, installed at key points, enable the monitoring of infiltration processes.

The system has been in operation for over two years. It manages runoff from a catchment area of approximately 1.8 hectares. This demonstrates its effectiveness in addressing local stormwater management challenges. The collected data has facilitated the development of a site-specific model, paving the way towards a better integration of nature-based solutions into urban and peri-urban projects.

The presentation will outline the concept and operation of the rain garden, its monitoring system, and the hydrological balances produced to date. These elements will highlight the key role of this type of infrastructure in the sustainable management of rainwater and its potential for meeting current urban environmental challenges.

De Knegt B., Breman B.C., Le Clec’h S., Van Hinsberg A., Lof M.E., Pouwels R., Roelofsen H.D. & Alkemade R., 2024. Exploring the contribution of nature-based solutions for environmental challenges in the Netherlands. Science of the Total Environment 929, DOI:10.1016/j.scitotenv.2024.172186.

Hasankhan A., Ghaeini-Hessaroeyeh M. & Fadaei-Kermani E., 2024. Enhancing Stormwater Management through Hydromodification Measures and Low Impact Development Strategies in Urban Areas: A Neighborhood-Scale Study. Water Resour Manage 1–19, DOI:10.1007/s11269-024-03971-0.

Hou X., Guo H., Wang F., Li M., Xue X., Liu X. & Zeng S., 2020. Is the sponge city construction sufficiently adaptable for the future stormwater management under climate change? Journal of Hydrology 588, 125055, DOI:10.1016/j.jhydrol.2020.125055.

Menberg K., Blum P., Schaffitel A. & Bayer P., 2013. Long-Term Evolution of Anthropogenic Heat Fluxes into a Subsurface Urban Heat Island. Environ. Sci. Technol. 47(17), 9747–9755, DOI:10.1021/es401546u.