Modelling hydrological response to nature-based solutions in a mixed land-use catchment

Mixed land-use river catchments are a common feature of cities around the world. The paradigm shift towards Nature-Based Solutions (NbS) and integrated catchment management over the last decade offers the potential for flood risk management interventions in these catchments which also bring a wide range of co-benefits. Whilst the efficacies of natural flood management interventions in rural landscapes (NFM) and sustainable drainage interventions in urban landscapes (SuDS) have received significant scientific attention, there is a relative lack of research that investigates interactions at scale between the two, which is especially relevant to peri-urban river catchments. This article presents the results of a hydrodynamic modelling study of a peri-urban stream in the UK which has experienced flooding in recent years. The research was designed to evaluate the spatial extent of benefits arising from NbS interventions in a mixed land-use catchment and to explore hydrological interactions between NbS located in rural and urban sub-catchments. Results indicate that whilst NbS interventions can reduce peak flows at both local and catchment scale, it is important to assess the spatial extent of these benefits, which diminish with increasing distance from the intervention. In addition, the concurrent installation of NbS in both the rural and urban sub-catchments may, in certain locations, offer significant benefits when compared to a focus on any one type of intervention. The research findings also support a view that integrated funding streams which address land-use across the catchment may lead to more cost-effective solutions than those which support specific intervention types.