Case study:Upper River Witham : Easton

From RESTORE
Jump to navigation Jump to search

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: 52° 49' 45.97" N, 0° 37' 31.86" W
Loading map...
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 Habitat and biodiversity
Country England
Main contact forename Matt
Main contact surname Parr
Main contact user ID
Contact organisation Environment Agency
Contact organisation web site http://www.gov.uk/government/organisations/environment-agency
Partner organisations
Parent multi-site project

Case_study:Upper Witham Restoration

This is a parent project
encompassing the following
projects
No
Post Restoration

Project summary

Edit project overview to modify the project summary.


Weir removal to restore bed gradient; channel narrowing and flow deflection to create flow variation and beneficial bed scour using log flow deflectors (vanes), open and enclosed log/faggot and brushwood mattresses (silt-traps) and earth, turf and silt filled log- or faggot-fronted enclosures; creation of sections of 2-stage channel and enhancing marginal wetland habitat by reprofiling eroded banks; excavation of pools in the river bed; increasing in-stream woody habitat by securing existing deadwood and hinging and pinning (layering) live riverside trees; and fencing to prevent bank erosion by livestock.

Project Objectives The pre-project surveys and assessments led to the identification of the following objectives for the enhancement scheme:

Reduce the impact of sediment inputs as a result of erosion caused by livestock.
Repair eroded banks and protect them from erosion in the future.
Trap sediment already in the system.
Improve flows and natural cleansing of spawning gravels.
Improve light levels in over-shaded sections.
Improve habitat for trout, coarse fish and native white-clawed crayfish.
Ensure that historic features within the Grade II Listed Historic Park and Garden are protected.

Three separate schemes based on these objectives were prepared.

Monitoring surveys and results

Edit project overview to modify the Monitoring survey and results.


In addition to the established annual fish monitoring programme downstream of Easton Walled Garden and invertebrate sampling at Easton Lane Bridge, visual inspections of the enhanced reach will be undertaken, and the fixed point photographic record will be updated to monitor the integrity and performance of the in-stream enhancements and record any changes they are making to river morphology. Post-works redd (trout spawning nest) surveys were undertaken upstream and downstream of Easton Lane. 6 redds were located in the upstream (Easton Park) section, but none were located downstream. These surveys provide a baseline for future monitoring.

Lessons learnt

Edit project overview to modify the lessons learnt.


1. The greatest detrimental impact upon river habitat is the legacy of past channel engineering. Straightening and widening of the channel and lowering of the river bed have disrupted/destroyed the natural pool-riffle sequence and disconnected the floodplain. The process of the river recovering these natural characteristics is very slow (centuries) because of the naturally low energy of the river and limited supply of coarse sediment.

2. Habitat improvement measures within the existing channel have generally been unsuccessful. Installed in-stream structures have not had the desired effect of creating scour and producing depth variation. This is because of the resistant nature of the predominantly clay substrate, loss of sediment (gravel) to historic channel engineering and lack of sediment (gravel) supply/retention within the present channel dimensions. Introduced brushwood and large woody material have improved cover and fish-holding habitat, but have not fundamentally changed the channel shape.

3. The weir removal at Easton has restored fish passage and better habitat to the formerly impounded reach upstream, although the above constraints (point 1) remain. Trout numbers observed in this reach indicate a recovery from past pollution incidents.


Image gallery


Easton 2.png
Easton 3.png
Easton 4.png
ShowHideAdditionalImage.png


Catchment and subcatchment

Catchment

River basin district Anglian
River basin Witham

Subcatchment

River name Upper Witham
Area category 10 - 100 km²
Area (km2)
Maximum altitude category Less than 100 m
Maximum altitude (m) 4646 m <br />0.046 km <br />4,600 cm <br />
Dominant geology Calcareous
Ecoregion Great Britain
Dominant land cover Arable and Horticulture
Waterbody ID GB105030056760



Other case studies in this subcatchment: Aubourn Rock Ramp and Habitat Works, Belton Floodplain Reconnection and River Restoration, Dysart Park, Grantham Habitat Improvement, Grantham Blue Green - Urban Reach, Little Ponton, Manthorpe Floodplain Reconnection, Papermill Weir Section in-channel restoration, River Witham Great Ponton, Stainby Road, Colsterworth, Syston and Barkston Restoration... further results


Site

Name Upper River Witham Easton
WFD water body codes GB105030051570
WFD (national) typology
WFD water body name Upper Witham Headwater to confluence Cringle Brook
Pre-project morphology
Reference morphology
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
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

Reach length directly affected (m)
Project started 01/10/2013
Works started
Works completed
Project completed
Total cost category 50 - 100 k€
Total cost (k€) 6666 k€ <br />66,000 € <br />
Benefit to cost ratio
Funding sources EA

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 Land drainage
Hydromorphology
Biology Fish
Physico-chemical Phosphate
Other reasons for the project


Measures

Structural measures
Bank/bed modifications Weir Removal, Berms, Flow Deflectors, Tree Hinging
Floodplain / River corridor Fencing
Planform / Channel pattern
Other
Non-structural measures
Management interventions
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

Link Description

Supplementary Information

Edit Supplementary Information