Climate change is expected to intensify extreme precipitation events, creating deep uncertainty for long‑term flood risk management in Voerendaal East. This flood‑prone area is located in the hilly landscape of South Limburg in the Netherlands. To address this uncertainty, this r
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Climate change is expected to intensify extreme precipitation events, creating deep uncertainty for long‑term flood risk management in Voerendaal East. This flood‑prone area is located in the hilly landscape of South Limburg in the Netherlands. To address this uncertainty, this research develops adaptation pathways to manage extreme precipitation through the year 2150. Eight extreme precipitation scenarios are analyzed, combining four return periods (T25, T50, T100, T200) with medium and high climate projections.
The adaptation need of Voerendaal East is defined as the runoff volume that exceeds a water depth threshold of 0.25 m within a two‑hour period at street level at the critical adaptation point. This point represents the location along the main runoff streamline where the maximum water depth occurs within the area of impact, which is the part of the catchment from which runoff converges toward the built‑up area. Results show that the adaptation need reaches up to 70,000 m³ for T200H in 2150, while remaining negligible for T25M.
To meet the adaptation need, seven hydrologically effective measures are identified: buffer optimization, new buffer location, temporary barrier at home, temporary barrier highway, diversion, stream optimization, and infiltration. Diversion provides the highest effectiveness (80,000 m³), while temporary measures are the most cost-efficient. Infiltration and diversion are the most expensive, where the infiltration measure requires a large land surface of 400,000 m2. Despite its large costs, the infiltration measure strengthens the landscape elements of South Limburg. The temporary measures and stream optimization require no land surface.
With these seven measures, 25 pathways are developed and evaluated from the perspectives of cost minimization, land minimization, avoidance of temporary measures, avoidance of temporary barriers at home, flexibility (choice and order of measures) and landscape integration. Buffer optimization emerges as the no-regret measure due to its favorable balance of cost, hydrological effectiveness and land requirement. Therefore, this measure serves as the first step in all pathways, except for the diversion pathway. It is assumed that responsibility for the initial measure of the pathways is not placed directly on citizens, but initially lies with the Limburg Water Authority.
The findings show that, overall, the flexible pathways outperform the rigid (diversion) pathway by reducing both overinvestment and land requirements. However, when the infiltration measure is applied, the rigid pathway becomes cheaper in terms of both cost and land use.
