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Descripción
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| Many hydropower installations are producing electricity using hydropeaking. Hydropeaking refers to rising or falling discharges caused either by the turning on or off of hydro-turbines to generate electricity according to variations in the market demand. As a result, downstream and upstream river hydrology is altered due to unnatural, rapid and significant fluctuations in discharge, which result also in unnatural changes in hydraulic parameters, in water quality and river morphology. Although river flows vary on multiple temporal scales, it is the assessment of short-term changes in river flow (sub-daily flow variation) that is important for understanding the effects of hydropower generation dams on riparian and aquatic species and communities. However, methods and software available today are only based on mean daily flows which mask the sub-daily fluctuations and are therefore not considered to be precise enough. The aim of this study was to define ecologically meaningful hydrological metrics based on sub-daily flow series and to compare such metrics between free-flowing rivers and rivers with hydropeaking. We used 1-hour interval flow data series measured at gauging stations for the last ten years from the Umea River (regulated by cascades of hydropower plants) and Vindel River (free-flowing) in Northern Sweden. We proposed hydrological metrics that provide information on ecologically significant features of sub-daily flow regimes and related water levels influencing aquatic, wetland and riparian ecosystems based upon a statistical analysis of the sub-daily flows and water levels. Metrics include aspects of magnitude (i.e. magnitude, ramping rate and amplitude (max/min)) and timing (i.e. timing, periodicity, duration and frequency). The metrics were compared and it was quantified how sub-daily flows along regulated rivers differ from natural variability measured at unregulated sites. Then, thresholds of natural sub-daily variation were defined and a degree of hydropeaking alteration were assessed according to deviations from the thresholds. Finally, Indicator of HydroPeaking Alteration (IHPKA) user-friendly software was developed. It is an easy-to-use tool for calculating the characteristics of natural and altered sub-daily flow regimes and will be useful for summarizing long periods of sub-daily hydrological data into a much more manageable series of ecologically relevant hydrological metrics. Devised metrics, identified thresholds and generated software are useful for catchment management plans, defining environmental flow targets, prioritizing river restoration or dam reoperation efforts and contributing information for relicensing hydropower dams. | |
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Internacional
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Si |
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Nombre congreso
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Congress SHF: HydroES 2016 |
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Tipo de participación
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960 |
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Lugar del congreso
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Grenoble, Francia |
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Revisores
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Si |
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ISBN o ISSN
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DOI
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Fecha inicio congreso
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16/03/2016 |
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Fecha fin congreso
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17/03/2016 |
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Título de las actas
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Proceedings of the Congress SHF: HydroES 2016. |