Drought and water scarcity | Research University of Twente

Rising Waters, Bigger Challenges: The Future of Flood Protection

By Borjana Bogatinoska, Civil Engineering and Management, UTwente

Flooding is becoming a bigger problem as climate change leads to stronger and more frequent storms. For years, we have relied on traditional engineering structures like levees, dams, and drainage systems to manage floods. While effective in many cases, these solutions often struggle to adapt to changing flood risks. For instance, about one-third of the dikes (more than 1000 km) in the Netherlands don’t meet current safety standards. Simply raising dike heights isn’t a sustainable fix, especially when we’re unsure how much sea levels will rise due to climate change. Measures—that combine nature-based solutions (NbS) with so called ‘grey’ infrastructure—are emerging as a game-changer in building resilient landscapes capable of reducing the frequency of floods and addressing broader environmental challenges such as restoring degraded ecosystems and improving biodiversity.

Blending Nature and Engineering

Hybrid flood measures combine the robustness of traditional engineering with the adaptive, self-sustaining, multifunctional benefits of natural systems. Nature-based solutions include restoring wetlands, bringing back a river’s original floodplain, or reintroducing its natural curves and bends that were straightened by humans. For example, the "Room for the River" program in the Netherlands uses these approaches. These measures slow down and store water, reducing the risk of damage to cities or infrastructure. At the same time, they support biodiversity and help capture carbon in the soil. Studies highlight the effectiveness of these measures; for example, the application of these hybrid approaches in Shanghai reduced flood risks while achieving a higher benefit-cost ratio compared to standalone grey infrastructure (Du et al., 2020).

Knowledge Exchange and Co-Creation

Effectively implementing hybrid solutions relies heavily on collaborating with the people that have the most at stake but possess non-technical knowledge – the stakeholders and the exchange of knowledge among those that possess technical knowledge – the practitioners. If we want people to adapt to a changing climate which can often mean changing their management practices (e.g. from growing specific crops to agroforestry), we need to sit down together, discuss and co-create these solutions together. By applying the SECI model (Socialization, Externalization, Combination, Internalization) by Nonaka and Takeuchi (1995), we demonstrated that co-creating solutions with stakeholders if well-structured can address challenges such as uncoordinated decision-making and limited technical expertise in reducing flood risks (Bogatinoska et al., 2024). Knowledge-sharing platforms, workshops, and other co-creation approaches increase the involvement of stakeholders and help these diverse audiences find common ground, with the result that the solutions are more environmentally sustainable and widely accepted among stakeholders.

Long-Term Monitoring of Nature-based solutions

Despite their promise, NbS are not often evaluated for their long-term performance, particularly under changing climate scenarios. Indicators that can be used to showcase the extent to which we can reduce the frequency of the flood wave (peak flows), the retention of large amounts of water (flood volumes) and socio-economic benefits are critical for assessing how effective these hybrid solutions can be. For instance, Moon et al. (2024) reported that hybrid measures could reduce peak flows by 37.3% and flood volumes by 71.5%. However, there are few approaches available to monitor these benefits consistently over a longer period of time.

The Path Forward

Introducing hybrid measures for reducing the risk of floods more widely requires that we overcome a number of barriers: harmonizing stakeholder interests, developing robust frameworks and indicators to assess the performance of these measures, especially in the long term and ensuring that there is enough technical capacity for implementing nature based solutions. Combining the knowledge of practitioners, stakeholders and academia about the effectiveness of these measures, as suggested in recent studies, can enhance the overall performance of hybrid flood resilience strategies and measures so that they can be more widely adopted for both safety and nature protection in flood-prone regions.

References:

Bogatinoska, B., Lansu, A., Dekker, S. C., Hugé, J., & Stoorvogel, J. (2024). Knowledge exchange between practitioners for the purpose of co-creating nature-based solutions. Ecosystems and People, 20(1). https://doi.org/10.1080/26395916.2024.2415305

Du, S., Scussolini, P., Ward, P. J., Zhang, M., Wen, J., Wang, L., Koks, E., Diaz-Loaiza, A., Gao, J., Ke, Q., & Aerts, J. C. J. H. (2020). Hard or soft flood adaptation? Advantages of a hybrid strategy for Shanghai. Global Environmental Change, 61, 102037. https://doi.org/10.1016/J.GLOENVCHA.2020.102037

Moon, H. T., Kim, J. S., Chen, J., Yoon, S. K., & Moon, Y. Il. (2024). Mitigating urban flood Hazards: Hybrid strategy of structural measures. International Journal of Disaster Risk Reduction, 108, 104542. https://doi.org/10.1016/J.IJDRR.2024.104542

Nonaka, I., & Takeuchi, H. (1995). The Knowledge-Creating Company. In Knowledge-Creating Company (Issue December 1991). Oxford University Press.

OpenAI. (2024). DALL-E 2. [AI image generator]. https://openai.com/dall-e-2