Case study:Millfield Plantation 2

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Location: 51° 58' 54.58" N, 0° 24' 13.71" E
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Project overview

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Status In progress
Project web site http://http://www.essexrivershub.org.uk/
Themes Flood risk management, Habitat and biodiversity, Hydromorphology, Water quality
Country England
Main contact forename Kieren
Main contact surname Alexander
Main contact user ID User:KierenAlexander
Contact organisation Essex Wildlife Trust
Contact organisation web site http://http://www.essexwt.org.uk/
Partner organisations
Parent multi-site project

Essex healthy headwaters

This is a parent project
encompassing the following
projects
No
Back Channel to be restored, River Pant in the foreground

Project summary

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The river restoration project at Millfield plantation builds on the work also being undertaken at Bocking Blackwater local nature reserve, Ironbridge Farm and Plough Hill farm. All the projects are linked both thematically and geographically and are focused on improving the status of the river under the water framework.

Currently the river Pant is failing under WFD, a number of issues have been identified including physical modification, fish passage and both point source and diffuse pollution. This manifests itself in a manner of ways, most notably with a heavily modified channel which has been deepened and in places straightened but most importantly disconnected from its floodplain by large artificial bunds. The land use is predominantly arable and this can lead to some pollution events both diffuse and one of such as oil and other contaminants. It should be noted that Essex and Suffolk water have done a huge amount to improve the status of this river by landowner interaction and education and this project aims to build on this.

After a period of consultation and a professional assessment looking at the feasibility of the project a plan was designed to start improving the water body. This will involve installing a pipe at the mouth of an old channel, we do not know exactly know what the original purpose of this channel was but it is likely to be an old mill race that due to historical management has been increasingly separated from the original channel. However, it now offers a unique chance to reconnect the floodplain and contribute to water quality via the installation of a new 300mm culvert and simple pipe.

This will allow the back channel to go from being inundated a handful of times a year to up to 15 or 16 times. This will only be transitory inundation, we are not planning on installing anything that will hold water back but it should be enough to kick start some changes in the vegetation structure promoting semi-aquatic and marginal vegetation. It will be this vegetation as it develops that allows the water to be filtered, silt will also be given the chance to settle out on the floodplain, further improving the condition of the river and its value to invertebrates and fish.

In addition to the back channel connection there will also be installation of several bits of woody debris further downstream to kick start geomorphological processes in the river such as riffle creation, berms, flow dynamics and some bank erosion. It also has a part to play in diffuse pollution removal by pushing water through soil which removes nitrate via dentrification.

All the consents are now in place for this project and earthworks as due to commence in August 2015, completing soon after. Once complete, we should start to see the benefits in the following winter.

Monitoring surveys and results

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There will be low key monitoring surrounding this project. Fixed point photography will be utilised to monitor any changes in vegetation and land forming.

There will be regular monitoring of riverflies in these reach, an improvement in these may point to an improvement in the water quality in this reach.

Lessons learnt

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The River Pant has low flow issues during the summer, and is also a conduit for the Ely-Ouse transfer system, these must be protected at all costs. Therefore any connection to the floodplain must take this into account. Also, due to the constraints of having to ensure that the landowner can keep access to the surrounding fields we have had to go for a formal connection, in an ideal world we would go for a more informal connection that would offer additional benefits to fish fry and avoid the need for an eel screen to prevent eels from being deposited in the new back channel.


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Catchment and subcatchment

Catchment

River basin district Anglian
River basin Combined Essex

Subcatchment

River name Blackwater Pant
Area category 10 - 100 km²
Area (km2)
Maximum altitude category Less than 100 m
Maximum altitude (m) 6868 m <br />0.068 km <br />6,800 cm <br />
Dominant geology Calcareous
Ecoregion Great Britain
Dominant land cover Arable and Horticulture
Waterbody ID GB105037033860



Other case studies in this subcatchment: Bocking Blackwater River Restoration


Site

Name Millfield Plantation
WFD water body codes GB105037041180
WFD (national) typology
WFD water body name Pant
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 Yes
Invasive species present Yes
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 2012/04/01
Works started 2014/08/11
Works completed
Project completed
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 Ess Kieren Alexander
Stakeholder engagement and communication Essex Wildlife Trust Kieren Alexander
Works and works supervision Essex Wildlife Trust Kieren Alexander
Post-project management and maintenance Essex Wildlife Trust Kieren Alexander
Monitoring Essex Wildlife Trust Kieren Alexander



Reasons for river restoration

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


Measures

Structural measures
Bank/bed modifications Creation of wooden deflectors
Floodplain / River corridor Floodplain reconnection
Planform / Channel pattern Introducing large woody debris, silt depositon on the flood plain
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

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