Scholarlink

<p>As part of a multi-year monitoring program at five run-of-river hydropower plants on the Iller River, the impact of intake screens with reduced bar spacing (20 mm) on fish mortality was investigated under real operating conditions. The study aimed to obtain objective data on the number, species composition, and possible causes of fish losses using automated video systems and supplementary hydraulic measurements. Between July 2016 and January 2019, approximately 640 hours of video footage were analyzed at the Altusried site. A total of 660 fish were detected, including seven native species. The average daily mortality rate was only 0.82 individuals. Despite approach velocities of up to 1.5 m/s - well above the recommended maximum of 0.5 m/s - fish mortality remained surprisingly low. The findings suggest that healthy, locally adapted fish species are capable of actively avoiding the intake area. The results indicate that under the conditions studied, intake screens with a 20 mm bar spacing do not constitute a significant mortality factor for mature fish. Therefore, the ecological benefit of narrower bar spacing should be critically evaluated. Rather than relying solely on technical retrofitting, combining such measures with habitat-improving strategies appears to be more ecologically effective and sustainable in the long term.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Ergebnisse zur Illerstrategie 2020: Fischschäden an Einlaufrechen - Auswirkungen auf die Fischpopulation

  • 期刊论文

  • 发表日期：

    2025年9月2日

查看全文
  • Dagobert Smija

摘要

As part of a multi-year monitoring program at five run-of-river hydropower plants on the Iller River, the impact of intake screens with reduced bar spacing (20 mm) on fish mortality was investigated under real operating conditions. The study aimed to obtain objective data on the number, species composition, and possible causes of fish losses using automated video systems and supplementary hydraulic measurements. Between July 2016 and January 2019, approximately 640 hours of video footage were analyzed at the Altusried site. A total of 660 fish were detected, including seven native species. The average daily mortality rate was only 0.82 individuals. Despite approach velocities of up to 1.5 m/s - well above the recommended maximum of 0.5 m/s - fish mortality remained surprisingly low. The findings suggest that healthy, locally adapted fish species are capable of actively avoiding the intake area. The results indicate that under the conditions studied, intake screens with a 20 mm bar spacing do not constitute a significant mortality factor for mature fish. Therefore, the ecological benefit of narrower bar spacing should be critically evaluated. Rather than relying solely on technical retrofitting, combining such measures with habitat-improving strategies appears to be more ecologically effective and sustainable in the long term.