Case study:Glaisdale Beck diversion scheme

This case study is pending approval by a RiverWiki administrator.

Approve case study

 

0.00

(0 votes)

To discuss or comment on this case study, please use the discussion page.

Location: 54° 25' 31.81" N, 0° 49' 31.28" W

Edit location

Loading map...

{"format":"googlemaps3","type":"HYBRID","minzoom":false,"maxzoom":false,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"limit":50,"offset":0,"link":"all","sort":[""],"order":[],"headers":"show","mainlabel":"","intro":"","outro":"","searchlabel":"... further results","default":"","import-annotation":false,"width":"auto","height":"400px","centre":false,"title":"","label":"","icon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"visitedicon":"","wmsoverlay":false,"zoom":14,"layers":[],"controls":["pan","zoom","type","scale","streetview","rotate"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"resizable":false,"kmlrezoom":false,"poi":true,"cluster":false,"clustergridsize":60,"clustermaxzoom":20,"clusterzoomonclick":true,"clusteraveragecenter":true,"clusterminsize":2,"imageoverlays":[],"kml":[],"gkml":["https://restorerivers.eu/wiki/images/d/db/Pangaea_parent_864201.kml"],"searchmarkers":"","fullscreen":false,"scrollwheelzoom":false,"showtitle":false,"hidenamespace":true,"template":"Location map popup","userparam":"","activeicon":"","pagelabel":false,"ajaxcoordproperty":"","ajaxquery":"","locations":[{"text":"\u003Cp\u003E\u003Cbr /\u003E\n\u003C/p\u003E\u003Cp\u003E\u003Cb\u003EProject Title:\u003C/b\u003E Glaisdale Beck diversion scheme\n\u003C/p\u003E\u003Cp\u003E\u003Cb\u003ECountry:\u003C/b\u003E \u003Ca href=\"/wiki/index.php?title=England\" title=\"England\"\u003EEngland\u003C/a\u003E\n\u003C/p\u003E\u003Cp\u003E\u003Cb\u003EProject Status:\u003C/b\u003E Complete\n\u003C/p\u003E\u003Cp\u003E\u003Cb\u003EThemes:\u003C/b\u003E Water quality\n\u003C/p\u003E\u003Cp\u003E\u003Cbr /\u003E\n\u003C/p\u003E","title":"Glaisdale Beck diversion scheme","link":"","lat":54.425503407424,"lon":-0.82535644993186,"icon":"/wiki/images/a/af/Red_marker.png"}]}

Left click to look around in the map, and use the wheel of your mouse to zoom in and out.

Project overview

Edit project overview

Status	Complete
Project web site
Themes	Environmental flows and water resources, Fisheries, Habitat and biodiversity, Hydromorphology, Land use management - agriculture, Monitoring, Water quality
Country	England
Main contact forename	Matthew
Main contact surname	Perks
Main contact user ID	User:Perksieuk
Contact organisation	Newcastle University
Contact organisation web site
Partner organisations
Parent multi-site project
This is a parent project encompassing the following projects	No

This case study hasn’t got a picture, you can add one by editing the project overview.

Project summary

Edit project overview to modify the project summary.

The Esk is a river of both ecological and economic importance at a national scale. It is the principle river in Yorkshire for Atlantic salmon and sea trout and is one of only two rivers on the east coast of England to have known populations of the freshwater pearl mussel, one of the most critically endangered bi-valves in the world. However, siltation and excessive suspended sediment concentrations (SSCs) have been attributed to causing their decline. This has led to local conservation and restoration efforts being driven by the National Park over the last 20 years.Previous research has highlighted the Glaisdale subcatchment as a key contributor to fine sediment fluxes in the Esk catchment. Through local surveys, a critical source area of fine sediment supply to the beck was identified. This was a section of exposed, near-vertical, ∼ 3 m high channel banks ∼ 100 m in length consisting of unconsolidated sediments and overlain by shallow surface vegetation, which is regularly accessed by livestock. The availability of accessible material is also exacerbated by progressive movement of a large hillslope failure complex which supplies large quantities of easily eroded sediment directly to the river channel. Such failures are well documented in the North York Moors. It was deemed that this combination of factors limited the potential for success of traditional channel margin stabilization approaches. Following consultation and the presentation of available options, the competent agencies decided the most appropriate course of action was to divert the existing channel away from the toe of the large hillslope landslide, and re-establish the stream course further to the north. The impact of this management was considered from a biotic and geomorphic viewpoint through the collection of data between 2007 and 2014.

Monitoring surveys and results

Edit project overview to modify the Monitoring survey and results.

From the analysis of over 2 years of river flow and in-stream sediment concentration data prior to, and following the diversion of Glaisdale Beck, it is clear that the sediment transfer regime has become more restrictive. This is evidenced by - Reductions in median suspended sediment concentrations from 35.19 to 18.98 mg/L, – 5 % reduction in flow-weighted mean sediment concentrations. – Negative trend in sediment concentrations. - Dampened response of sediment concentration during periods of high flow.

Although direct monitoring of the hydrology and sediment dynamics at Glaisdale beck was concluded in 2009, 2 years after the channel diversion, the longer term development of the site was observed through site visits up until 2014. During this period, continued erosion in the form of a headward migrating knick point (visible as a step in the river bed) has resulted in a progressive wave of channel instability that has migrated upstream. This is the response to over-steepening of the channel gradient in the vicinity of the original channel diversion.

Due to a lack of appropriately engineered grade control (drop) structures in the engineered reach this has resulted in channel bed lowering, bank undercutting and lateral bank failures upstream. During this time extensive bank erosion and channel widening occurred. At this particular site, erosion was evident only 2 weeks after the initial diversion with the knickpoint migrating through the reach, lowering the bed elevation. In response, the banks started to slump. However, due to increased channel width the final phase of bank collapse resulted in a soil wedge at the base of the bank which appears to have protected the toe of the bank preventing further lateral expansion.

Lessons learnt

Edit project overview to modify the lessons learnt.

Channel reconfiguration can be effective in mitigating fine sediment flux in headwater streams but the full value of this may take many years to achieve whilst the fluvial system slowly readjusts.

The channel is continuing to adjust to the diversion with evidence of continuing local instability. It is therefore recommended that this approach to reducing the fine sediment flux of upland rivers should not be adopted as standard practice.

However, where significant modifications to upland channels are made, comprehensive in-stream monitoring and geomorphological assessments should be regularly conducted to evaluate the response of the river to the new conditions.

This research has highlighted the importance of ensuring appropriate controls on sediment release during in-stream works and effective installation and maintenance of grade control (drop) structures. If these measures had been rigorously applied the overall goal of reducing fine sediment flux through the fluvial system could have been achieved in a more timely fashion.

Image gallery

Edit Image gallery

Catchment and subcatchment Select a catchment/subcatchment Edit the catchment and subcatchment details (affects all case studies in this subcatchment) Catchment River basin district Humber River basin Esk and Coast Subcatchment River name Glaisdale Beck catchment (trib of Esk) Area category 10 - 100 km² Area (km2) 15.615.6 km² <br />1,560 ha <br /> Maximum altitude category 200 - 500 m Maximum altitude (m) 401401 m <br />0.401 km <br />40,100 cm <br /> Dominant geology Calcareous Ecoregion Great Britain Dominant land cover Heather Waterbody ID GB104027068070 Site Edit site Name WFD water body codes WFD (national) typology WFD water body name Pre-project morphology Reference morphology Desired post project morphology Heavily modified water body National/international site designation Local/regional site designations Protected species present Invasive species present Species of interest Dominant hydrology Dominant substrate River corridor land use Average bankfull channel width category Average bankfull channel width (m) Average bankfull channel depth category Average bankfull channel depth (m) Mean discharge category Mean annual discharge (m3/s) Average channel gradient category Average channel gradient Average unit stream power (W/m2) Project background Edit project background Reach length directly affected (m) 400400 m <br />0.4 km <br />40,000 cm <br /> Project started 2007/09/21 Works started 2007/10/10 Works completed 2007/10/10 Project completed 2014/10/01 Total cost category Total cost (k€) Benefit to cost ratio Funding sources Cost for project phases Phase cost category cost exact (k€) Lead organisation Contact forename Contact surname Investigation and design Stakeholder engagement and communication Works and works supervision Post-project management and maintenance Monitoring Durham University Reasons for river restoration Edit reasons for restoration Mitigation of a pressure Excessive fine sediment threatening aquatic habitats Hydromorphology Biology Physico-chemical Other reasons for the project Measures Edit Measures Structural measures Bank/bed modifications Floodplain / River corridor Planform / Channel pattern Other Non-structural measures Management interventions Social measures (incl. engagement) Other Monitoring Hydromorphological quality elements Edit Hydromorphological quality elements Element When monitored Type of monitoring Control site used Result Before measures After measures Qualitative Quantitative Channel pattern/planform Yes Yes No Yes No Continuity of sediment transport Yes Yes No Yes No Improvement Biological quality elements Edit biological quality elements Element When monitored Type of monitoring Control site used Result Before measures After measures Qualitative Quantitative Physico-chemical quality elements Edit Physico-chemical quality elements Element When monitored Type of monitoring Control site used Result Before measures After measures Qualitative Quantitative Any other monitoring, e.g. social, economic Edit Other responses Element When monitored Type of monitoring Control site used Result Before measures After measures Qualitative Quantitative Monitoring documents Upload monitoring documents Additional documents and videos Upload additional documents Additional links and references Edit links and references Link Description Supplementary Information Edit Supplementary Information