Hydrologic performance of Natural Water Retention Measures: outcomes from the LIFE BEWARE project test site

The consequences of climate change are exacerbated by land-use changes, which affect the control of rainfall-runoff relations and the impact on flooding hazards. Effectively, urbanization is constantly contributing to the increase of impervious areas and reducing the time-to-peak. The effect of Natural Water Retention Measures (NWRMs) in the mitigation of these phenomena is known. Nevertheless, this kind of sustainable infrastructures are still poorly known by citizens and administrators, and consequently barely adopted in many parts of the European Countries. The LIFE BEWARE project aims to enhance hydraulic safety and spread good practices on rainwater management by promoting and facilitating the adoption of NWRMs in the Altovicentino, a highly rainy foothills area in Northern Vicenza Province (Veneto Region, Italy). In order to support the dissemination activities, some full-scale NWRMs have been realized in the area of intervention of the project. The hydrological functioning of these nature-based green infrastructures is continuously monitored thanks to the installation of devices measuring inlet and outlet runoff. The aim of this research is to present the realized NWRMs and the adopted monitoring system, and to analyze the data collected during the firsts two years. Results show that at this field-scale experiment all the monitored interventions were able to manage almost all the rainfall events occurred during these two years and the fraction of the rainfall runoff that reached the outflow was always less than 2%. Finally, the research provides insights in better understanding the behavior of NWRMs exposed to different weather and environmental conditions. This also adds some useful information at the design phase of such green infrastructure.