The scope for a system-based approach to determine fine sediment targets for chalk streams
The scope for a system-based approach to determine fine sediment targets for chalk streams
Fine sediment has a critical role in river ecosystems and is essential for habitat heterogeneity, ecosystem structure and function. Expansion and intensification of specific land uses, including agriculture, have increased fine sediment inputs into river networks. The detrimental impacts of excessive fine sediment on river ecosystems have been well documented and numerous sediment targets have been proposed or adopted to assess the gap between target and current levels of fine sediment. Where sediment targets exist, these are often over-simplified and applied across a wide range of river environments irrespective of the processes of fine sediment deposition and the tolerance or sensitivity of river biota to fine sediment. Thus, targets often fail to provide a reliable basis for identifying the need for management interventions to restore ecosystem health. This review adopts a system-based approach to the impacts of fine sediment after reviewing the suitability of existing targets for guiding management in chalk stream catchments specifically. Chalk streams are groundwater-dominated systems characterised by stable hydrological, ecological and thermal regimes and thus respond differently to excessive fine sediment compared with other fluvial systems. Chalk streams are often subject to high levels of sedimentation and siltation despite their low suspended sediment loads. In this paper, we review the characteristic processes and dynamics of chalk streams and how these influence fine sediment accumulation. The impacts of excessive fine sediment on chalk stream habitats and biota and the role ecosystem engineers play in the processes of fine sediment dynamics are discussed. Finally, we discuss the application of fine sediment targets for chalk streams in relation to the implementation of both source and process-based techniques for meeting the requirement for improved ecosystem management.
Chalk stream, Fine sediment, Gravel-bed, Sediment budget, Sediment targets
105541
Mondon, Beth
af15d99f-67c6-49f3-93fe-05a9844bd914
Sear, David
ccd892ab-a93d-4073-a11c-b8bca42ecfd3
Collins, Adrian L.
700e5f6a-4de3-4406-ad7a-d9d8ec0a5069
Shaw, Peter
dcb6c9af-bf38-4dfe-8395-8aeac2ad5cc7
Sykes, Tim
e622a522-7490-4fc8-9869-0f376f73561c
1 November 2021
Mondon, Beth
af15d99f-67c6-49f3-93fe-05a9844bd914
Sear, David
ccd892ab-a93d-4073-a11c-b8bca42ecfd3
Collins, Adrian L.
700e5f6a-4de3-4406-ad7a-d9d8ec0a5069
Shaw, Peter
dcb6c9af-bf38-4dfe-8395-8aeac2ad5cc7
Sykes, Tim
e622a522-7490-4fc8-9869-0f376f73561c
Mondon, Beth, Sear, David, Collins, Adrian L., Shaw, Peter and Sykes, Tim
(2021)
The scope for a system-based approach to determine fine sediment targets for chalk streams.
CATENA, 206 (11), , [105541].
(doi:10.1016/j.catena.2021.105541).
Abstract
Fine sediment has a critical role in river ecosystems and is essential for habitat heterogeneity, ecosystem structure and function. Expansion and intensification of specific land uses, including agriculture, have increased fine sediment inputs into river networks. The detrimental impacts of excessive fine sediment on river ecosystems have been well documented and numerous sediment targets have been proposed or adopted to assess the gap between target and current levels of fine sediment. Where sediment targets exist, these are often over-simplified and applied across a wide range of river environments irrespective of the processes of fine sediment deposition and the tolerance or sensitivity of river biota to fine sediment. Thus, targets often fail to provide a reliable basis for identifying the need for management interventions to restore ecosystem health. This review adopts a system-based approach to the impacts of fine sediment after reviewing the suitability of existing targets for guiding management in chalk stream catchments specifically. Chalk streams are groundwater-dominated systems characterised by stable hydrological, ecological and thermal regimes and thus respond differently to excessive fine sediment compared with other fluvial systems. Chalk streams are often subject to high levels of sedimentation and siltation despite their low suspended sediment loads. In this paper, we review the characteristic processes and dynamics of chalk streams and how these influence fine sediment accumulation. The impacts of excessive fine sediment on chalk stream habitats and biota and the role ecosystem engineers play in the processes of fine sediment dynamics are discussed. Finally, we discuss the application of fine sediment targets for chalk streams in relation to the implementation of both source and process-based techniques for meeting the requirement for improved ecosystem management.
Text
The scope for a system-based approach to determine fine sediment targets for chalk streams
More information
Accepted/In Press date: 15 June 2021
e-pub ahead of print date: 23 June 2021
Published date: 1 November 2021
Additional Information:
This research was funded by an Environment Agency PhD studentship supported by the University of Southampton. Rothamsted Research receives strategic funding from UKRI-BBSRC (UK Research and Innovation – Biotechnology and Biological Sciences Research Council) and the contribution to this paper by ALC was supported by grant award BBS/E/C/000I0330.
Keywords:
Chalk stream, Fine sediment, Gravel-bed, Sediment budget, Sediment targets
Identifiers
Local EPrints ID: 450634
URI: http://eprints.soton.ac.uk/id/eprint/450634
ISSN: 0341-8162
PURE UUID: 9b505b4b-ac04-4f96-bfaf-b8e28b3f4525
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Date deposited: 05 Aug 2021 16:31
Last modified: 17 Mar 2024 06:42
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Author:
Adrian L. Collins
Author:
Peter Shaw
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