Case study:Little Ponton

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Location: 52° 52' 21.71" N, 0° 37' 21.40" W
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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 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 Grantham Angling Association Fly Fishing Section
Parent multi-site project

Upper Witham Restoration

This is a parent project
encompassing the following
projects
No
Brushwood mattress in restoration section

Project summary

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Project Objectives

  • To reduce fine sediment inputs caused by bank erosion.
  • Trap mobile fine sediments already in the river.
  • To improve conveyance during higher flows and reduce flood risk.
  • To improve in-stream habitats and the bed structure to benefit fish and invertebrates, including white-clawed crayfish.

The Enhancement Scheme The enhancement scheme was completed in two phases. A short section downstream of Great Ponton Mill was completed in February 2013 and the second, the continuation downstream to Whalebone Lane, Little Ponton, was completed in mid-August 2014. Prior to the enhancement work the in-river habitat was in generally good condition, however opportunities were identified to provide additional cover and food supply for a range of aquatic organisms together with measures to modify the flow to improve the structure of the riverbed and reduce the deposition of fine sediment.

The works consisted of brushwood mattress installation, Hinged Trees, Log Flow Deflectors and Vanes, improved stock fencing and ford refurbishment.

Monitoring surveys and results

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A fixed point photographic record has been set up and this, together with visual inspections, will be used to monitor the integrity and performance of the in-stream structures. A programme of fine sediment sampling and Wolman Pebble Counts to monitor the coarser riverbed material has also been established. In combination they will determine and record changes to river morphology as the result of the works. The established crayfish monitoring site at the bottom of the reach is already surveyed every 2 years and this will give an indication of the impact of the scheme on crayfish numbers. Finally additional ongoing invertebrate sampling will identify any ecological and water quality changes that occur.

Lessons learnt

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Learning lessons from the earlier GAAFFS work, willow logs were was not used in the subsequent phase of enhancement work. Instead logs, branches and brushwood generated by the management of other riverside tree and shrub species were used to create a variety of structures to protect vulnerable banks from erosion, narrow the channel and trap suspended fine sediment.


Image gallery


Post restoration
Post restoration
Post Restoration
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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, Manthorpe Floodplain Reconnection, Papermill Weir Section in-channel restoration, River Witham Great Ponton, Stainby Road, Colsterworth, Syston and Barkston Restoration, Upper Cringle Floodplain Restoration Project... further results


Site

Name Little Ponton
WFD water body codes GB105030056780
WFD (national) typology
WFD water body name Witham Confluence Cringle Brook to Confluence Brant
Pre-project morphology
Reference morphology Lower Cringle Brook
Desired post project morphology
Heavily modified water body Yes
National/international site designation
Local/regional site designations
Protected species present Yes
Invasive species present No
Species of interest Native Crayfish / Brown Trout
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) 16201,620 m <br />1.62 km <br />162,000 cm <br />
Project started 01/02/2013
Works started
Works completed
Project completed
Total cost category 10 - 50 k€
Total cost (k€) 2700027,000 k€ <br />27,000,000 € <br />
Benefit to cost ratio
Funding sources Environment Agency

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 brushwood mattress installation, Hinged Trees, Log Flow Deflectors and Vanes.
Floodplain / River corridor
Planform / Channel pattern
Other
Non-structural measures
Management interventions Improved stock fencing and ford refurbishment.
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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