Downstream environmental effects of dam operations: Changes in habitat quality for native fish species |
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Authors: | Alex García Klaus Jorde Evelyn Habit Diego Caamaño Oscar Parra |
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Affiliation: | 1. Center of Environmental Sciences EULA‐Chile, Universidad de Concepción, Barrio Universitario s/n, Casilla 160‐C, Concepción, Chile;2. Center for Ecohydraulics Research, University of Idaho, 322 East Front Street, Suite 340, Boise, ID 83702, USA;3. sje–Schneider and Jorde Ecological Engineering GmbH, Viereichenweg 12, 70569 Stuttgart, Germany |
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Abstract: | Hydropeaking dam operation and water extractions for irrigation have been broadly stated as alterations to natural flow regimes, which have also been noticed in the Biobío Watershed, in Central Chile, since 1996. In the Biobío River, most of native fish species are endemic and very little is known about them. Their ecological and social values have never been estimated, and there is lack of information about their habitat preferences. Furthermore, changes on fish habitat availability due to natural and/or man‐made causes have not been evaluated. In this study, eight native fish species, in a representative reach of the Biobío River, were studied and their preferred habitats were surveyed and characterized. A hydrodynamic model was built and linked to the fish habitat simulation model CASiMiR. Fuzzy rules and fuzzy sets were developed for describing habitat preference of the native fish species. CASiMiR was then used to simulate how physical habitat conditions vary due to flow control (i.e. upstream dams). Results show how overall habitat quality, expressed as weighted usable area (WUA) and hydraulic habitat suitability (HHS), changes and fluctuates due to the dam operation and how the daily hydropeaking is influencing quantity, quality and location of different habitats. The study suggests that the analysed fish are highly susceptible to flow control, as dams are currently operated, and fish habitat improvement suggestions are proposed. Copyright © 2010 John Wiley & Sons, Ltd. |
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Keywords: | fish habitat modelling CASiMiR hydropeaking native fish species multi‐use river Biobí o Chile |
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