Future flow and water temperature scenarios in an impounded drainage basin: implications for summer flow and temperature management downstream of the dam.

Khorsandi, Mostafa ORCID: https://orcid.org/0000-0002-4359-1600; St-Hilaire, André ORCID: https://orcid.org/0000-0001-8443-5885; Arsenault, Richard; Martel, Jean-Luc; Larabi, Samah; Schnorbus, Markus et Zwiers, Francis (2023). Future flow and water temperature scenarios in an impounded drainage basin: implications for summer flow and temperature management downstream of the dam. Climatic Change , vol. 176 , nº 12. p. 164. DOI: :10.1007/s10584-023-03634-w.

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Résumé

Water temperature is a key variable affecting fish habitat in rivers. The Sockeye salmon (Oncorhynchus nerka), a keystone species in north western aquatic ecosystems of North America, is profoundly affected by thermal regime changes in rivers, and it holds a pivotal role in ecological and economic contexts due to its life history, extensive distribution, and commercial fishery. In this study, we explore the effects of climate change on the thermal regime of the Nechako River (British Columbia, Canada), a relatively large river partially controlled by the Skins Lake Spillway. The CEQUEAU hydrological-thermal model was calibrated using discharge and water temperature observations. The model was forced using the Fifth generation of ECMWF Atmospheric Reanalysis data for the past and meteorological projections (downscaled and bias-corrected) from climate models for future scenarios. Hydrological calibration was completed for the 1980–2019 period using data from two hydrometric stations, and water temperature calibration was implemented using observations for 2005–2019 from eight water temperature stations. Changes in water temperature were assessed for two future periods (2040–2069 and 2070–2099) using eight Coupled Model Intercomparison Project Phase 6 climate models and using two Shared Socioeconomic Pathway scenarios (4.5 and 8.5 W/m2 by 2100) for each period. Results show that water temperatures above 20°C (an upper threshold for adequate thermal habitat for Sockeye salmon migration in this river) at the Vanderhoof station will increase in daily frequency. While the frequency of occurrence of this phenomenon is 1% (0–9 days/summer) based on 2005–2019 observations, this number range is 3.8–36% (0–62 days/summer) according to the ensemble of climate change scenarios. These results show the decreasing habitat availability for Sockeye salmon due to climate change and the importance of water management in addressing this issue.

Type de document:	Article
Mots-clés libres:	CEQUEAU model; climate change; Nechako River; river temperature
Centre:	Centre Eau Terre Environnement
Date de dépôt:	06 févr. 2024 20:59
Dernière modification:	06 févr. 2024 20:59
URI:	https://espace.inrs.ca/id/eprint/14171

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