Author(s): Giovanni Negro; Sara Viale; Alessandro Guglielmetto; Paolo Vezza

Linked Author(s): Giovanni Negro, Paolo Vezza

Keywords: Ecological Flows; Hydropower repowering; Habitat Integrity Index; MesoHABSIM; Alpine rivers

Abstract: At the intersection of environmental protection and energy transition, Italy is called to find new approaches to safeguard river ecosystems while modernizing its hydropower infrastructure. Achieving this balance under the new Ecological Flow (EF) framework requires integrated strategies that reconcile ecological integrity with energy efficiency. This study evaluates the eco-hydrological and operational implications of redefining EFs for run-of-river (RoR) plants, exploring synergies between new EF regimes and potential plant re -powering through increased maximum water abstraction capacity. Focusing on three Alpine rivers (Ayasse, Brenve, and Savara), EF design was based on the mesohabitat simulation model (MesoHABSIM) and on the Habitat Integrity Index (IH), an ecologically meaningful indicator composed of five quality classes. Hydropower performance was assessed by computing the corresponding total volume of water diverted to turbines. Results showed that improving habitat quality from “Bad” to “High” required base flow (BF) increases of 1.6-9.4 times current rates, reducing diverted water volumes by 8-28%. However, coupling higher BF with expanded water abstraction capacity enhanced hydropower production by 124-169% while preserving river ecological integrity. This framework supports the design of RoR configurations that harmonize ecological sustainability, economic feasibility, and climate resilience.

DOI: https://doi.org/10.64697/iahr.proc.ise2026.abs.205

Year: 2026