Modelling Nature-Based Solutions with Quasi-2D Model

Abstract

Due to the influence of climate change, urbanization and land-use changes, floods have been the most frequent type of hazard among hydrometeorological hazards. Solutions for flood mitigation can be conventional engineering solutions and Nature-Based Solutions (NBS). The latter one has been proved to be a more sustainable approach to cope with the effect of future changes. In this study, we apply a quasi-2D physiographic drainage-inundation model for simulations of NBS. This model uses a water balance equation and flow formulas for flow calculation. It was compared with full hydrodynamic models and was proved to have the potential to accurately predict the potential floods. The case study area is Cul de Sac catchment on Sint Maarten. Cul de Sac is one of the areas on Sint Maarten that is most vulnerable to flooding. A multifunctional detention pond is planned and simulated as NBS to reduce flood risks. The simulated results indicate that the detention pond can reduce the total inundation area and reduce inundation depths in the downstream areas. However, one detention pond is not enough to solve the flood problems in the case study area. A combination of structural measures and additional non-structural measures could provide a better effect on flood mitigation.