Diversion channels are engineered or natural pathways designed to redirect excess stormwater away from vulnerable areas and rivers prone to flooding, towards safer locations such as retention basins or the sea. By providing an alternative route for water during heavy rainfall, they reduce flood risk and protect homes, roads, and critical infrastructure. Diversion channels can be permanent or temporary.
More solutions for flood management can be found under stormwater drainage systems.
Feasibility & Local Applicability
In islands like Curaçao and Aruba, which have arid climates and no major rivers, large-scale diversion channels will not be applicable. Instead, maintaining and improving existing natural drainage systems, such as the rooien system, is an important adaptation measure.
In St. Martin, widening existing drainage channels and adding new ones where necessary is a priority adaptation measure. While full-scale diversion projects may be limited by space and cost, smaller interventions integrated into stormwater management plans are feasible.
Co-benefits
Diversion channels can support groundwater recharge when paired with retention areas, helping alleviate water scarcity during dry periods. They also reduce damage to roads and property, improve public safety, and can be designed to enhance green spaces or wetlands, supporting biodiversity. In some cases, diverted water can be stored for irrigation or municipal use, adding economic value.
Equity & Vulnerability Considerations
Flooding disproportionately affects low-income communities located in low-lying or poorly drained areas. Well-planned diversion channels can protect these neighborhoods, but care must be taken to avoid shifting flood risk downstream. Community engagement is essential to ensure fair distribution of benefits and avoid unintended harm. Maintenance programs should involve local stakeholders to build trust and resilience.
Costs
Medium | Costs vary widely depending on scale and design. Large engineered channels can require significant investment for excavation, lining, and control structures. However, such large scale projects will not be necessary on the islands of Curacao, Aruba and St. Martin, as there are no major rivers. Smaller upgrades to existing drainage systems are more affordable but still require regular maintenance.
Case studies & Examples
Literature
- Abebe, Y. A., Ghorbani, A., Nikolic, I., Vojinovic, Z., & Sanchez, A. (2019). Flood risk management in Sint Maarten–A coupled agent-based and flood modelling method. Journal of environmental management, 248, 109317.
- Serra‐Llobet, A., Kondolf, G. M., Magdaleno, F., & Keenan‐Jones, D. (2022). Flood diversions and bypasses: Benefits and challenges. Wiley Interdisciplinary Reviews: Water, 9(1), e1562.