European BECCA project: Solutions for safe reservoirs, integrated into their environment and respectful of biodiversity, as part of climate change adaptation in mountain areas

In 2022, all climate indicators point to drier-than-average conditions across much of Europe. The combined effects of low rainfall and high temperatures have led to widespread and prolonged drought, affecting many sectors of society. The greatest rainfall deficits were recorded in the Alpine arc (Source: Copernicus), with significant consequences for the population and economy of mountain areas. The critical conditions observed in 2022 merely confirm the trend of climate change over recent decades, with serious impacts on Alpine regions: severe summer droughts detrimental to agriculture in rural mountain areas, to drinking water supplies, to fire risk and to hydroelectric power generation; and, with rising temperatures, a lack of snow in winter detrimental to winter sports resorts. Local stakeholders are working to identify effective and sustainable solutions for adapting to climate change. One of the preferred solutions involves the creation of small and medium- sized reservoirs to store water, thereby helping mountain regions adapt to climate change by ensuring the continuation of economic activities and an adequate level of safety for the communities living there. However, regulatory authorities in France and Italy have noted that these small and medium-sized reservoirs in the cross-border region can pose risks to the population in the event of failure, as well as having significant impacts on the environment and natural habitats. The European BECCA project – Sustainable and Safe Basins for Ecology, designed for Adaptation to Climate Change – funded by the European Interreg ALCOTRA France-Italy programme, aims to provide the tools to design safe reservoirs and rehabilitate existing ones using nature-based techniques. This project focuses specifically on the France– Italy cross-border area corresponding to the Alpine arc, but the results are widely applicable beyond this to other mountainous or foothill regions. In particular, the BECCA project aims to establish technical recommendations for the design, construction, rehabilitation and management of small and medium-sized, simple, low-cost reservoirs that guarantee an adequate level of safety for downstream populations, protect against natural hazards, and place a strong emphasis on environmental considerations by taking the environment into account from the design stage to minimise ecological impacts. Through a guidance document, the BECCA project proposes operational techniques for the naturalisation and revitalisation of reservoirs using nature-based solutions.