Case study:River Bure

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Location: 52° 49' 27", 1° 12' 23"
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Project overview

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Status Complete
Project web site
Themes Fisheries, Habitat and biodiversity
Country England
Main contact forename Murray
Main contact surname Thompson
Main contact user ID
Contact organisation River Restoration Centre
Contact organisation web site
Partner organisations
Parent multi-site project
This is a parent project
encompassing the following
projects
No
River Bure - following restoration

Project summary

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The National Trust in conjunction with the Blickling fishing club undertook a two-phase restoration project (in 2008 and 2010) at the River Bure, Norfolk. This involved installation of Large Woody Debris (LWD) with the overall aim of improving in-channel and marginal habitats, by re-establishing natural river processes interrupted by past management activities.

The stretch of the Bure flowing through the Blickling Estate had been severely over-widened due to historic dredging to increase channel and holding capacity for several mills in the area. Within the 7 km of river channel that border the Blickling Estate there are four mills and several bypassed meanders. Siltation added to the degraded state of the river, which was heavily wooded.

Felling trees to create in-channel LWD was identified as a good way to increase habitat and restore natural processes to the Bure (historically fallen trees had been removed by the Environment Agency and local fishing club). (Introduction of naturally occurring LWD to encourage flow diversity and increase channel sinuosity). Riparian habitats were of high quality, comprising ancient woodland and alder and willow carr, therefore restoration works were restricted to options which would have a low impact on the site and surrounding habitats i.e. use of heavy machinery was not advised.

Objectives were:

- To improve river habitat by re-instating woody debris

- To increase the stock of wild brown trout

- To enhance biodiversity and conservation value of the reach

The project was completed in two phases. Phase 1 work was completed in November 2008 over four weeks. There was no allocated budget for the project, so works had to be economical and non-technical as access to the site was limited. Much of the work was therefore based on intuition and what was deemed to be aesthetically “right” for the location. Trees were felled into the channel with some minor modifications made to their in-stream position to comply with EA by-laws and fishing requirements. Work was carried out by volunteers using chainsaws, a hand winch and plastic boat. This phase increased fish catch numbers (based on Blickling fishing club records).

Phase 2 of the project was completed in November 2010, encompassing a baseline survey and monitoring. In this phase the introduction of LWD was more adventurous. Consequently, the results of phase 2 were even more dramatic than phase 1. Effects of restoration appeared to be proportional to the amount of LWD introduced into the river.

The approach at both stages involved adhering to the following:

-selection of trees which were already likely to fall into the channel

-fell them so they remained attached to the root plate

-allow branches to penetrate the river bed to secure the tree

-only if necessary use a stake to prevent movement

-modify the position if necessary to maintain other channel functions e.g. fishing points

-felling more than one tree at each location allows a web of branches and twigs to form, diversifying habitats and anchoring the “structure”

Since 2010 the river has continued to become more diverse in terms of the range of habitats. Sediment trapped by LWD has increase in channel and marginal vegetation. The redistribution of sediments has resulted in a naturally developing channel. Areas of faster flows have begun to clean gravels, with areas of reduced flow velocity causing deposition.

The National Trust has identified an increasing enthusiasm for retaining naturally occurring LWD as part of sustainable river management and restoration since the completion of this project. In the local area request to remove LWD have reduced dramatically. The potential reduction in management costs is likely to encourage LWD to be retained in its natural position or slightly modified as opposed to removed. The River Restoration Centre would like to thank Dave Brady from The National Trust for providing the case study content and photographs.

Monitoring surveys and results

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Lessons learnt

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Image gallery


Phase 1 site 2 before restoration (D.Brady, The National Trust)
Phase 1 site 2 during restoration (D.Brady, The National Trust)
Phase 1 site 2 after restoration (D.Brady, The National Trust)
Phase 2 site 1 before restoration (D.Brady, The National Trust)
Phase 2 site 1 during restoration (D.Brady, The National Trust)
Phase 2 site 1 after restoration (D.Brady, The National Trust)
example of naturally occurring LWD that would have previously been removed (D.Brady, The National Trust)
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Catchment and subcatchment

Catchment

River basin district Anglian
River basin Broadland Rivers

Subcatchment

River name Bure (Mid)
Area category 10 - 100 km²
Area (km2)
Maximum altitude category Less than 100 m
Maximum altitude (m) 56
56 m
0.056 km
5,600 cm
Dominant geology Calcareous
Ecoregion Great Britain
Dominant land cover Arable and Horticulture
Waterbody ID GB105034055660



Site

Name Bure at Blickling Estate
WFD water body codes GB105034055660
WFD (national) typology
WFD water body name Bure
Pre-project morphology Over-widened, Over deepened, Straightened
Reference morphology Sinuous, Pool-riffle
Desired post project morphology
Heavily modified water body No
National/international site designation
Local/regional site designations
Protected species present No
Invasive species present No
Species of interest Brown trout
Dominant hydrology
Dominant substrate Gravel, Silt
River corridor land use Intensive agriculture (arable), Broadleaf/mixed woodland (semi natural)
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

Reach length directly affected (m) 300
300 m
0.3 km
30,000 cm
Project started 2008/11/01
Works started
Works completed
Project completed 2010/11/01
Total cost category 1 - 10 k€
Total cost (k€) 6
6 k€
6,000 €
Benefit to cost ratio
Funding sources National Trust

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



Reasons for river restoration

Mitigation of a pressure
Hydromorphology
Biology
Physico-chemical
Other reasons for the project historic channel widening


Measures

Structural measures
Bank/bed modifications Introducing large woody debris, Improvement of natural flows, Adding sinuosity
Floodplain / River corridor
Planform / Channel pattern Channel narrowing, Channel naturalisation
Other
Non-structural measures
Management interventions No longer remove naturally occurring LWD
Social measures (incl. engagement)
Other


Monitoring

Hydromorphological quality elements

Element When monitored Type of monitoring Control site used Result
Before measures After measures Qualitative Quantitative

Biological quality elements

Element When monitored Type of monitoring Control site used Result
Before measures After measures Qualitative Quantitative

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

Element When monitored Type of monitoring Control site used Result
Before measures After measures Qualitative Quantitative


Monitoring documents



Additional documents and videos


Additional links and references

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Supplementary Information

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