Applying a two‐dimensional hydrodynamic model to estimate fish stranding risk downstream from a hydropeaking hydroelectric station

Abstract

Fish stranding is of global concern with increasing hydropower operations using hydropeaking to respond to fluctuating energy demand. Determining the effects hydropeaking has on fish communities is challenging because fish stranding is dependent on riverscape features, such as topography, bathymetry and substrate. By using a combination of physical habitat assessments, hydrodynamic modelling and empirical data on fish stranding, we estimated the number of fish stranding over a 5-month period for three model years in a large Prairie river. More specifically, we modelled how many fish potentially stranded during the years 2019, 2020 and 2021 across a 16 km study reached downstream from E.B. Campbell Hydroelectric Station on the Saskatchewan River, Canada. Fish stranding densities calculated from data collected through remote photography and transect monitoring in 2021 were applied to the daily area subject to drying determined by the River2D hydrodynamic model. The cumulative area subject to change was 90.05, 53.02 and 80.74 km 2 for years 2019, 2020 and 2021, respectively, from June to October. The highest number of stranded fish was estimated for the year 2021, where estimates ranged from 89,800 to 1,638,000 individuals based on remote photography and transect monitoring fish stranding densities, respectively, 157 to 2,856 fish stranded per hectare. Our approach of estimating fish stranding on a large scale allows for a greater understanding of the impact hydropeaking has on fish communities and can be applied to other riverscapes threatened by hydropeaking.

Characterizing the effects of morphological microstructures and hydropeaks on fish stranding in rivers

“…This model could also test the influence of stranding of the temporal and spatial variations in habitat suitability for the different taxa close to stranding microstructures (Bätz et al, 2022). Recently developed methods could also be used to identify the disconnected microstructures and quantify their associated stranding risk (Larrieu et al, 2021) or to estimate fish stranding risk on a large scale using a combination of physical habitat assessments, hydrodynamic modeling, and empirical data (Glowa, Kneale, et al, 2023). Moreover, the longitudinal effects of peaking intensity parameters (Hauer et al, 2017) could be assessed with the help of a longitudinal model of hydropeaking waves calibrated with multiple hydrological gauges (Greimel et al, 2023).…”

Impact of interbasin transfer hydroelectric project on downstream aquatic habitat

“…A hydropeaking dam upstream can affect the biodiversity of the downstream ecosystem through hydrologic alterations (Bürgler et al, 2023; Meile et al, 2011; Moreira et al, 2019; Ray & Sarma, 2011; Wang et al, 2019). Artificial flow fluctuations due to hydropeaking can hinder the sustenance rate of aquatic organisms (Glowa et al, 2023; Greimel et al, 2018; Hedger et al, 2023). Thus, to protect the ecosystem and to acquire the maximum benefit of electricity generation, there is a need for an integrated water resources management of regulated rivers (Widén et al, 2022).…”