Steep-slope viticulture: The effectiveness of micro-water storage in improving the resilience to weather extremes

Steep-slope vineyards are widely distributed in the Mediterranean region and have a pivotal role in wine production, economic development, and cultural heritage. Nevertheless, they are threatened by climate change in terms of opposite weather extremes, such as heavy rainfalls and long-lasting droughts. In response, rainwater harvesting systems have emerged as valuable solutions for managing water resources and controlling related problems. Of primary importance is the identification of suitable sites for installation. However, a systematic selection procedure still needs to be explored; it is necessary for morphologically complex vineyards that include historical features of significant cultural value (such as terraced systems). To fill this gap, this study employed a high-resolution overflow simulation model that combines a set of criteria to identify the optimal network of water harvesting structures (also drawing on traditional knowledge) and quantify the potential for water storage during rainfall of varying intensities. The study area considered is located within the “Soave Traditional Vineyards” (north of Italy) site, a Globally Important Agricultural Heritage System (GIAHS) recognized by FAO. The surface overflow was simulated considering two key rainstorms that occurred in the last few years at different time intervals. 53 potential sites for water harvesting were selected according to field survey, runoff simulation, and topographic analysis. The results indicate that the water potentially collected from designed sites could have a double function: (1) mitigate the surface overflow that can potentially cause downslope terrace collapse or even flooding villages; (2) provide irrigation water for vineyards during water scarcity scenarios. The spatial distribution of the water collected could undoubtedly guide sustainable decisions in steep-slope viticultural systems under climate change forcing.