EcoPeak4Fish: A Multidisciplinary Project Targeting the Protection of Fish Populations Affected by Hydropeaking ^†

Abstract

Hydroelectricity demand is still growing due to its reduced carbon impact and strong dispatchability. Concurrently, the necessity to support self-sustainable fish populations in a cost-effective way and restore water-related ecosystems is urgent. The impacts of rapid and artificial flow fluctuations caused by peak electricity demand, i.e., hydropeaking, on fish fauna are still largely unknown, particularly for cyprinid species. Flow-refuges (e.g., lateral deflectors) are believed to help fish with rapidly changing flows and high currents. Nonetheless, most studies addressing hydropeaking and its impacts focus on salmonids. Recent studies have assessed the utility of flow-refuges for cyprinids in controlled experimental conditions. However, fish responses to hydropeaking and the use of flow-refuges in peaking rivers remain unknown. Rethinking the hydropower operation to improve fish habitat during key lifecycle stages (e.g., spawning) can be an option. However, these measures may affect the hydropower production profit. Including habitat use in models of hydropower plant (HPP) optimal management is usually achieved by adding restrictions regarding minimum flows. The feedback between the available habitat and profit has not been explicitly modelled. Including a description of how the available habitat changes with water flow can help estimate tradeoffs between profit maximization and habitat preservation and to inform the development of flow restrictions. EcoPeak4Fish intends to answer these questions in a multidisciplinary approach with the 4E’s: Ecology, Engineering and Economics in the profit of the Ecosystem protection. This project aims to assess the effects of hydropeaking in cyprinid species, propose a flow-refuge prototype and assess its cost-effectiveness, and develop a framework to adapt the HPP operation scheme to maximize profits and environmental benefits for a sustainable use of hydropower energy. The project intends to answer the following questions: How do fish react under hydropeaking conditions? Are flow-refuges an effective measure to mitigate impacts and contribute to the self-sustainability of fish populations? How can one find the HPP operation scheme that maximizes profit and power production while maximizing the suitable habitat for fish populations? This knowledge will be fundamental to implement new and redefine operational schemes, to recommend design criteria for flow-refuges, and to mobilize policy-makers to define legal instruments for hydropeaking.