Scientists Meet Scientists – TUM-IAS Wednesday Coffee Talk by Prof. Jürgen Geist: “Innovative hydropower – green or red?”

Events, WCT |

On 3 July 2024, Prof. Jürgen Geist (Aquatic Systems Biology, TUM) will talk about "Innovative hydropower – green or red?!”


Innovative hydropower developments promise to improve fish passage and to reduce fish mortality and habitat deterioration. So far, these promises have rarely been validated in realistic field settings. In a large-scale field study, we compared fish passage, mortality, external and internal injury patterns, movement corridors, and habitat effects at eight different types of innovative and conventional hydropower plants in Germany under different operational regimes. The suite of methodological approaches included sonar-based fish behavior assessment, the use of sensor fish as well as mortality/injury assessments of wild fish and hatchery-reared test fish, biological community monitoring and habitat characterization. The findings revealed that innovative hydropower technologies sometimes produced greater adverse ecological effects than conventional ones, and that operational modes had a strong effect on the observed fish mortalities and injury patterns across species. Strong differences in seasonal and diurnal fish movement patterns were evident. Most fish followed the main current through the turbine corridor and did not use alternative bypasses. Physical barriers with 15 mm and 20 mm bar spacing could not prevent most fish from entrainment and were passed by specimens exceeding the expected size thresholds from modeling. Concerning habitat quality, dams and weirs interrupted the river continuum, reduced flow current and increased siltation upstream of dams, resulting in biological community shifts. These effects were not significantly mitigated by most innovative technologies over the study period, despite the promise of some of them to do so. This study provides novel insights into which technologies and operational modes are least harmful under the given site conditions. It also suggests that assessments of fish passage and ecological effects can greatly benefit from realistic field studies. Such information can help improve the operation of existing and the design of future hydropower plants.

Date: July 3, 2024
Time: 13:00 CEST (until approx. 14:00)
Location: online

Registration: The TUM-IAS Wednesday Coffee talks are held online via Zoom. To register and to receive the Zoom link, please send an email to


Every Wednesday after lunch, it's all about a new topic - current research highlights at TUM, insights into the work of our Fellows from all over the world, sometimes even topics not usually found at TUM, such as history or theology.

The talks held online start every Wednesday during TUM lecture time at 13:00 CE(S)T. Everyone is welcome - TUM researchers of all levels, students, visiting scholars, and anyone interested!

Each final Wednesday of the month, a topic related to the United Nations' 17 Sustainable Development Goals will be featured as a part of the Seminar Series of European Universities on Sustainability, a new initiative of the TUM-IAS in partnership with universities across Central, Eastern, and Southeastern Europe.

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An overview of upcoming and past TUM-IAS Wednesday Coffee Talks can be found at the TUM-IAS Wednesday Coffee Talk Overview.