Author(s): Eugenio Mazzocchi; Fabio Tognola; Federico Camparada; Bernhard Monai

Linked Author(s):

Keywords: Migration; Lift; Fish Ladder

Abstract: Restoring longitudinal fish migration at the Airolo compensation basin required a solution capable of operating under reservoir fluctuations of approximately 7.7 metres and substantial spatial constraints at the dam's left abutment. A hybrid system combining a vertical-slot fish ladder with a fish lift was therefore designed and implemented by IG Ritom Ticino for Azienda Elettrica Ticinese, with ecohydraulic support from Der Wasserwirt. The system enables upstream passage across a head difference of up to 14 metres and ensures attraction flow continuity during all lift phases. Downstream passage is provided through an adapted pressurised bypass integrated into the minimum flow release. Hydraulic design was based on Salmo trutta fario and validated against national and international guidelines. Automation of valves, gates and lift cycles ensures reliable operation under variable hydraulic conditions. The installation represents a novel application of a ladder-lift combination in an Alpine hydropower context and contributes to the cantonal programme for restoring connectivity along the upper Ticino River.

DOI: https://doi.org/10.64697/iahr.proc.ise2026.abs.305

Year: 2026