A comprehensive inventory of large hydropower systems in the Italian Alpine Region

The threat of climate change and water resource overexploitation to river network ecosystems and their natural flows is evident, particularly in mountainous regions where hydropower production is also responsible for significant alterations of the natural streamflow. Hydrological modeling in these watersheds is hindered by limited knowledge of technical and geometrical information. Key characteristics and parameters related to hydropower operating schedule and their hydraulic infrastructures are usually hard to obtain as they are mostly confidential data producers hold. Consequently, modeling hydropower systems over large domains often relies on simplified methods which may decrease the reliability of these studies. In response to these challenges, we created a comprehensive inventory designed to model the interaction between natural stream networks and hydropower-related infrastructures at the mesoscale. This inventory, tailored for the large hydropower systems in the northern mountainous region of Italy (Italian Alpine Region - IAR), includes detailed hydraulic parameters essential for the reliability of water-energy-nexus modeling implementations. The selected region includes over 300 large hydropower systems with complex infrastructures, among those, nearly 160 plants are reservoir-fed, causing a significant alteration in streamflow. To assess the reliability of the provided inventory, we employed HYPERstreamHS as the reference hydrological model. We assessed the accuracy of our designed inventory by comparing the modelled hydropower production with the finest observations available, which are province-aggregated monthly hydropower production data from 1995 to 2008. The outcomes revealed a commendable similarity ranging from 83% to 100% across simulated areas, with an overall average of 90%, solidly confirming the accuracy of the crafted inventory.