Case study:Emmanuel’s Common Reconnection Project

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Location: 52° 43' 12.08" N, 0° 42' 57.57" E

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Project overview

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Status	Complete
Project web site
Themes	Fisheries, Habitat and biodiversity, Hydromorphology
Country	England
Main contact forename	Helen
Main contact surname	Mandley
Main contact user ID	User:JoshRRC
Contact organisation	Norfolk Rivers Trust
Contact organisation web site	http://www.norfolkriverstrust.org/
Partner organisations
Parent multi-site project
This is a parent project encompassing the following projects	No

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Project summary

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The River Nar has been historically modified for human use, changing its channel size and shape, and in places the river’s course. These changes have negatively impacted on the wildlife of the river. The River Nar through Emmanuel’s Common has historically been used for water meadows to graze animals. The river has been deepened and straightened to enable drainage of the site and to increase water flow to power Newton Mill. By looking at historic maps and investigating on the ground you can see the old meandering channel through the woodland.

The project within the common has now been completed. We have delivered the restoration scheme as planned where we wanted to reconnect 600m of old channel constructing one new length of channel to make the meander sequence link up.

The project aims to reconnect the old meandering channel, open up some of the channel by removing scrub to allow light in, improve flow regime, improve fish & invertebrate habitat, and improve aquatic and riparian plant habitat.

The lower channel accounted for 80% of the project time. The available route passed through a slightly raised part of the flood-plain and in the middle reaches it was a challenge to peel away enough ground to make the correct, naturally shallow cross-section. There was little fall to play with too and the main river to which the new channel returned has been dredged and so tuning the gradient proved very tricky. It was worth the effort though. When the flows finally broke through the new channel worked perfectly, with good velocity and no unintentional impoundments.

Monitoring surveys and results

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Please use the link to find out about the Electrofishing surveys for the project http://www.norfolkriverstrust.org/wp-content/uploads/2016/02/Electrofishing-doc.pdf

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Catchment and subcatchment Select a catchment/subcatchment Edit the catchment and subcatchment details (affects all case studies in this subcatchment) Catchment River basin district Anglian River basin North West Norfolk Subcatchment River name Nar Area category 100 - 1000 km² Area (km2) Maximum altitude category Less than 100 m Maximum altitude (m) 2121 m <br />0.021 km <br />2,100 cm <br /> Dominant geology Calcareous Ecoregion Great Britain Dominant land cover Arable and Horticulture Waterbody ID GB105033047792 Other case studies in this subcatchment: The Pentney Restoration Project Site Edit site Name WFD water body codes GB105033047792 WFD (national) typology WFD water body name Nar DS Blackborough Drain 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 Edit project background Reach length directly affected (m) Project started 2014/06/02 Works started Works completed Project completed 2014/11/14 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 Stakeholder engagement and communication Works and works supervision Post-project management and maintenance Monitoring Reasons for river restoration Edit reasons for restoration Mitigation of a pressure Hydromorphology Reconnect old channel, improve flow regime Biology Improve fish habitat and biodiversity Physico-chemical Other reasons for the project Measures Edit Measures Structural measures Bank/bed modifications Floodplain / River corridor Reinstating the old channel by creating a short linking channel upstream, and reconnecting the meanders downstream Planform / Channel pattern Other Non-structural measures Management interventions Social measures (incl. engagement) Other Monitoring Hydromorphological quality elements Edit Hydromorphological quality elements Element When monitored Type of monitoring Control site used Result Before measures After measures Qualitative Quantitative Biological quality elements Edit biological quality elements Element When monitored Type of monitoring Control site used Result Before measures After measures Qualitative Quantitative Physico-chemical quality elements Edit 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 Edit Other responses Element When monitored Type of monitoring Control site used Result Before measures After measures Qualitative Quantitative Monitoring documents Upload monitoring documents Additional documents and videos Upload additional documents Additional links and references Edit links and references Link Description Supplementary Information Edit Supplementary Information