November 2017 Devil s Den Weir - Severn Rivers Trust · Case Study November 2017 Devil’s Den Weir...
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The weir at Devil’s Den is one of three barriers to fish migration along a 1.94km length of the River Stour between the A449 (Ashwood) and A456 (Stewponey) bridges, and even through it is the smallest of the three in terms of height, it is no less a barrier than the remaining two. After assessing the barriers in the upper Stour, this weir was chosen to have remediation works carried out upon it due to its size, ease of access, available budget, and the amenability of the landowner. It is understood that this weir was installed in the 18 th Century when Prestwood house was demolished and rebuilt for the Foley family as part of a series of ornamental pools, cascades and waterfalls that were encompassed in a wet-garden. This information was uncovered through a commissions Archaeological and Historical Survey of the site. The proposed works to allow fish migration upstream was to cut a 40% notch in the centre of the weir structure to the river bed, opening up a sufficient gap through which fish could pass. The weir, being ~10m wide and ~1m high, had a head-drop of ~30cm. This means the notch cut would be 4m wide, and would allow fish migration at flow regimes between Q95 and Q10. The landowner was also keen to carryout some river bank works as part of the project, to increase flood-capacity and reduce bank erosion along his stretch (~110m). This was included in the project proposal, which consisted of: Cutting a 4m notch in the centre of the weir Regrading the river banks to an angle of ~45° Installing soft revetments and Large Woody Debris along a small section of the graded river bank toe downstream of the weir Scattering grass seed across all the newly graded banks to help them regenerate and bind the soils. The whole project work schedule was as follows: July - October 2016: Walkover surveys and site visits. November 2016: February 2017: Create project proposal, contact contractors for quotes. February 2017: Apply for Environmental Regulations Permit (EPR). March - August 2017: Host community events for future works, supply additional information for EPR, await for permits to be granted. September 2017: Finalise plan with farmer and contractor, arrange start date. 28 th - 30 th September 2017: Work on the ground. October 2017 - Write final project report. Case Study November 2017 Devil’s Den Weir Key Facts River Basin District Severn Catchments River Stour (12 Waterbodies) Start Date July 2016 End Date October 2017 Budget £20,000 Project River Stour Catchment Restoration Project Partners Severn Rivers Trust, Environment Agency, Worcestershire Wildlife Trust, The Wildlife Trust for Birmingham and the Black Country. River Stour Catchment Restoration Project The River Stour Catchment Restoration Project comprises 12 water- bodies, all of which are classified as ‘Moderate’, ‘Poor’, or ‘Bad’ Ecological Status under the Water Framework Directive (2000/60/EC: WFD). The project has a long term vision to improve water quality throughout the catchment under the project title ‘Salmon in the Stour’ (2017-2021). The catchment restoration project was a pilot year building towards the launch of ‘Salmon in the Stour’, which sought to gather data and information, plan future project work, and deliver some small-scale, “quick-wins” work on the ground. As fish migration is a major issue within the catchment, the instream barriers were assessed and a suitable project was proposed within the timeframe and allocated project budget. The outcome would allow fish migration through an existing barrier, and begin to remediate one of the most important factors for the catchment failing WFD. Devil’s Den Weir, Prestwood
Transcript of November 2017 Devil s Den Weir - Severn Rivers Trust · Case Study November 2017 Devil’s Den Weir...
The weir at Devil’s Den is one of three barriers to fish
migration along a 1.94km length of the River Stour
between the A449 (Ashwood) and A456 (Stewponey)
bridges, and even through it is the smallest of the three in
terms of height, it is no less a barrier than the remaining
two. After assessing the barriers in the upper Stour, this
weir was chosen to have remediation works carried out
upon it due to its size, ease of access, available budget,
and the amenability of the landowner.
It is understood that this weir was installed in the 18th
Century when Prestwood house was demolished and
rebuilt for the Foley family as part of a series of
ornamental pools, cascades and waterfalls that were
encompassed in a wet-garden. This information was
uncovered through a commissions Archaeological and
Historical Survey of the site.
The proposed works to allow fish migration upstream was
to cut a 40% notch in the centre of the weir structure to
the river bed, opening up a sufficient gap through which
fish could pass. The weir, being ~10m wide and ~1m
high, had a head-drop of ~30cm. This means the notch
cut would be 4m wide, and would allow fish migration at
flow regimes between Q95 and Q10. The landowner was
also keen to carryout some river bank works as part of
the project, to increase flood-capacity and reduce bank
erosion along his stretch (~110m). This was included in
the project proposal, which consisted of:
Cutting a 4m notch in the centre of the weir
Regrading the river banks to an angle of ~45°
Installing soft revetments and Large Woody Debris
along a small section of the graded river bank toe
downstream of the weir
Scattering grass seed across all the newly graded
banks to help them regenerate and bind the soils.
The whole project work schedule was as follows:
July - October 2016: Walkover surveys and site visits.
November 2016: February 2017: Create project
proposal, contact contractors for quotes.
February 2017: Apply for Environmental Regulations
Permit (EPR).
March - August 2017: Host community events for
future works, supply additional information for EPR,
await for permits to be granted.
September 2017: Finalise plan with farmer and
contractor, arrange start date.
28th - 30
th September 2017: Work on the ground.
October 2017 - Write final project report.
Case Study November 2017
Devil’s Den Weir Key Facts
River Basin
District
Severn
Catchments River Stour (12 Waterbodies)
Start Date July 2016
End Date October 2017
Budget £20,000
Project River Stour Catchment
Restoration Project
Partners Severn Rivers Trust,
Environment Agency,
Worcestershire Wildlife Trust,
The Wildlife Trust for
Birmingham and the Black
Country.
River Stour Catchment Restoration
Project The River Stour Catchment Restoration Project comprises 12 water-
bodies, all of which are classified as ‘Moderate’, ‘Poor’, or ‘Bad’
Ecological Status under the Water Framework Directive (2000/60/EC:
WFD). The project has a long term vision to improve water quality
throughout the catchment under the project title ‘Salmon in the
Stour’ (2017-2021).
The catchment restoration project was a pilot year building towards
the launch of ‘Salmon in the Stour’, which sought to gather data and
information, plan future project work, and deliver some small-scale,
“quick-wins” work on the ground.
As fish migration is a major issue within the catchment, the instream
barriers were assessed and a suitable project was proposed within
the timeframe and allocated project budget. The outcome would allow
fish migration through an existing barrier, and begin to remediate one
of the most important factors for the catchment failing WFD.
Devil’s Den Weir, Prestwood
Figure 1: Prestwood weir from the Right Hand Bank before remediation works were carried out.
Figure 2: Works completed. The 4x1m notch in the centre of the weir, to the river bed, now allows fish migration upstream for all species.
Project Budget and
Expenditure
Item Source Total £
Bathymetric &
Topographic
Surveys
Maltby Land Surveys
Ltd 2070.00
Historic Report Archaeology
Warwickshire 1740.00
Hydraulic Modelling Mike & Matt Beach 2520.00
EPR Environment Agency 210.00
Estate Charges Environment Agency 625.80
Weir Notching and
bank Work WM Longreach Ltd 7893.60
SRT Staff Inc. T&S Severn Rivers Trust 4227.54
Overheads Severn Rivers Trust 631.27
19918.21 Total
What Does The Future Hold? The ‘Salmon in the Stour’ project will build on the
success of the Catchment Restoration project, and
continue to improve the river Stour to benefit the
environment, ecology and local community. Through
partnership working, the project will target more barriers
to fish migration in the Stour catchment, along with
biodiversity issues, misconnections and litter.
We will be engaging closely with the local community to
help them become custodians of the River Stour and be
proud to live within the catchment. A range of volunteer-
ing events will be available, and through working with
local schools, we hope we will be able to encourage
young people to take a more active role in caring for the
River Stour throughout their lives.
Severn Rivers Trust Reg Office: Unit 5, Hope House Farm Barns, Hope House Lane,
Martley, Worcestershire, WR6 6QF.
Company registration number: 6642409,
Registered charity number: 1134096.
Project Officer: Alex Clark 07810 546 129
General E-mail: [email protected]
Website: www.severnriverstrust.com
Contact Information
Devil’s
Den Weir
