Making informed choices: Implementing Nature-based Solutions for effective freshwater management in temperate catchments

Nature-based Solutions (NbS) are ways in which the environment can be modified or managed to restore, protect, or mimic natural processes and functions. It has been suggested that NbS can enhance the resilience of the freshwater environment to the impacts of climate change and other human pressures such as diffuse agricultural pollution. Overall, evidence from catchments in temperate climates shows that NbS can positively influence a wide range of hydrological and ecological properties and processes, providing beneficial outcomes for the management of hydrological extremes (floods and low flows), water quality, and biodiversity. However, NbS also have the potential to result in disbenefits, trade-offs or unintended consequences when implemented in unsuitable settings, or with ineffective management of interventions. In some cases, studies were unable to fully determine the effectiveness of NbS due to insufficient monitoring. The provision of benefits or disbenefits from some NbS can vary temporally, with influences such as rainfall and flow conditions playing a role in the outcomes that can be achieved. Despite an increase in the publication of studies examining the effects of NbS, significant knowledge gaps remain. In particular, monitoring over longer timescales and in different catchment settings is needed to evaluate the benefits and disbenefits of NbS to better inform their future implementation and management. Evidence gaps are a known barrier to the uptake of NbS. We find that conflicting land-use priorities are also an issue. Knowledge gaps and wider socio-economic barriers need to be addressed to achieve optimal outcomes from NbS.