Robinson Christopher Thomas
Experimental floods in Switzerland
Project Number: CH-6419
| hydrology, limnology, glaciology|
The river Spöl in eastern Switzerland flows through the Swiss National Park. The river here is fragmented by two reservoirs, resulting in two flow-managed sections: the upper and low- er Spöl separated by Ova Spin reservoir. Environmental high flows (e-flows) have been im- plemented since 2000 to improve the ecological integrity in these sections of the river. While the upper Spol resembles an alpine stream with canyon like structures and large rocks, the lower Spol contains gravel sediments strongly influenced by tributary influxes from the Clouzza valley. As an indicator for biotic changes in the river, stream macroinvertebrates have been monitored in both sections over the last 18 years. Both stretches have shown major changes in macroinvertebrate assemblages resulting from the e-flows, although being some- what different in each stretch. For example, the density of the common crustacean Gammarus decreased in the upper part while increasing in the lower Spöl. Nevertheless, the number of taxa increased in both sections over time. Additional habitat measures of the riverbed also detected differences in each site of the river as shown, for example, in cross-sectional profiles recorded over time in each section.
In the second chapter, I analyzed the drift patterns of MZBs over three separate e-floods in three different streams in Switzerland. These different e-floods are distinguished by their flow magnitude, duration, and season within the year. We investigated how the flow magni- tude correlated with MZB’ drift and seston. In particular, we studied if there were general discharge thresholds for the drifting of MZB. Moreover, the effects of the floods were inves- tigated using the periphyton of stones and MZB density before and after the floods. Most of the invertebrates in the drift were in the first hour of the floods. There were as well some differences in the taxonomic groups. Trichopterans were the most resilient group of the EPT- taxa.
Kevic M. (2017) Eperimental floods in Switzerland. Masters Thesis, Universität Zürich, Nr. 11-729-068. 83 pp.PDF Master thesis
Last update: 4/13/18
Source of data: ProClim- Research InfoSystem (1993-2020)
Update the data of project: CH-6419