Title: Evaluation of mitigation measures to reduce hydropeaking impacts on river ecosystems a a case study from the Swiss Alps
Authors : Tonolla, Diego
Bruder, Andreas
Schweizer, Steffen
Published in : Science of The Total Environment
Volume(Issue) : 574
Pages : 594
Pages to: 604
Publisher / Ed. Institution : Elsevier
Issue Date: 2017
License (according to publishing contract) : Licence according to publishing contract
Type of review: Peer review (Publication)
Language : English
Subjects : Alpine river; Altered flow regime; Ecological indicator; Hydropower; River restoration
Subject (DDC) : 577: Ecology
Abstract: New Swiss legislation obligates hydropower plant owners to reduce detrimental impacts on rivers ecosystems caused by hydropeaking. We used a case study in the Swiss Alps (hydropower company Kraftwerke Oberhasli AG) to develop an efficient and successful procedure for the ecological evaluation of such impacts, and to predict the effects of possible mitigation measures. We evaluated the following scenarios using 12 biotic and abiotic indicators: the pre-mitigation scenario (i.e. current state), the future scenario with increased turbine capacity but without mitigation measures, and future scenarios with increased turbine capacity and four alternative mitigation measures. The evaluation was based on representative hydrographs and quantitative or qualitative prediction of the indicators. Despite uncertainties in the ecological responses and the future operation mode of the hydropower plant, the procedure allowed the most appropriate mitigation measure to be identified. This measure combines a basin and a cavern at a total retention volume of 80,000m3, allowing for substantial dampening in the flow falling and ramping rates and in turn considerable reduction in stranding risk for juvenile trout and in macroinvertebrate drift. In general, this retention volume had the greatest predicted ecological benefit and can also, to some extent, compensate for possible modifications in the hydropower operation regime in the future, e.g. due to climate change, changes in the energy market, and changes in river morphology. Furthermore, it also allows for more specific seasonal regulations of retention volume during ecologically sensitive periods (e.g. fish spawning seasons). Overall experience gained from our case study is expected to support other hydropeaking mitigation projects.
Departement: Life Sciences und Facility Management
Organisational Unit: Institute of Natural Resource Sciences (IUNR)
Publication type: Article in scientific Journal
DOI : 10.1016/j.scitotenv.2016.09.101
ISSN: 0048-9697
URI: https://digitalcollection.zhaw.ch/handle/11475/6663
Appears in Collections:Publikationen Life Sciences und Facility Management

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