Lboro_accepted_JEMA.pdf (3.52 MB)
The effects of sediment traps on instream habitat and macroinvertebrates of mountain streams
journal contribution
posted on 2021-06-18, 09:00 authored by Kate MathersKate Mathers, Carmen Kowarik, Cristina Rachelly, Christopher T Robinson, Christine WeberSediment transport in mountain streams can be a major hazard to downstream infrastructure. Consequently, sediment traps are a common feature in many high gradient streams to retain large volumes of sediment and protect settlements from major sediment transport events. Despite the wide application of these instream structures, there is little knowledge regarding the environmental and ecological effects on streams. Here, we investigated the hydromorphological effects of sediment traps on instream habitats and associated macroinvertebrate communities in four impacted and three non-impacted streams in Switzerland. Sediment traps significantly disrupted the sediment regime homogenising grain size percentiles compared to the natural stepwise downstream fining in control streams. This disruption in the sediment regime resulted in finer grain size distributions upstream of the sediment trap, and reduced substrate diversity in the sediment retention basin and just downstream of the trap. The reductions in substrate diversity resulted in an altered macroinvertebrate community composition. Further, the disconnection in sediment transport led to a lack of longitudinal correlation in macroinvertebrate communities. Refugia provision downstream of the sediment trap, and resource availability within the retention basin, were diminished, potentially reducing resilience of macroinvertebrate assemblages to instream disturbances. The effects of sediment traps were most likely localised in three of the four streams with substrate diversity recovering to comparable control values within 8 wetted widths (ca. 50 m) downstream of the trap associated with natural longitudinal fining. In contrast, ecological and environmental effects propagated downstream in one impacted stream with no recovery being evident. Sediment retention basins in the impacted streams provided a local artificially unique habitat of dynamic-braided channels. Our results indicate that sediment traps can significantly disrupt the sediment regime with important consequences for instream ecology and environmental conditions, although these effects can be system specific. Further work is needed to fully understand the effects of sediment traps in mountain streams to assist resource managers in the mitigation and future construction of these structures.
Funding
KLM, CK and CR gratefully acknowledge the support of the research program “Wasserbau und Ökologie” funded by the Swiss Federal Office for the Environment (FOEN) Grant 16.0113.PJ/P501-1050, the Swiss Federal Institute of Aquatic Science and Technology (Eawag), the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), the Laboratory of Hydraulics, Hydrology and Glaciology at ETH Zurich (VAW) and the Laboratory of Hydraulic Constructions at EPF Lausanne (LCH) to undertake the research.
History
School
- Social Sciences and Humanities
Department
- Geography and Environment
Published in
Journal of Environmental ManagementVolume
295Publisher
Elsevier BVVersion
- AM (Accepted Manuscript)
Rights holder
© ElsevierPublisher statement
This paper was accepted for publication in the journal Journal of Environmental Management and the definitive published version is available at https://doi.org/10.1016/j.jenvman.2021.113066.Acceptance date
2021-06-09Publication date
2021-06-16Copyright date
2021ISSN
0301-4797Publisher version
Language
- en
Depositor
Kate Mathers. Deposit date: 17 June 2021Article number
113066Usage metrics
Categories
No categories selectedLicence
Exports
RefWorks
BibTeX
Ref. manager
Endnote
DataCite
NLM
DC