Case study:River Soar Floating Pennywort Eradication

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Location: 52° 39' 16.18" N, 1° 7' 39.64" W

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Project overview

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Status	In progress
Project web site
Themes	Fisheries, Habitat and biodiversity, Water quality
Country	England
Main contact forename	Rebecca
Main contact surname	Brunt
Main contact user ID
Contact organisation	Environment Agency
Contact organisation web site	http://https://www.gov.uk/government/organisations/environment-agency
Partner organisations	Leicester City Council, Canal and River Trust
Parent multi-site project
This is a parent project encompassing the following projects	No

Project picture

Project summary

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Around 96km of the River Soar and River Trent in Leicestershire and Nottinghamshire have in the past been choked by the non-native plant Floating Pennywort.

The plant was first identified in Leicestershire in 2004, thought to be an escapee from a private garden. It soon got a hold, growing fast in our waterways and out-competing our native plants. It can grow up to 20cm a day and spreads to block out light for other aquatic plants. The problem is so extensive that we have been carrying out annual herbicide spraying and some removal of the plant since 2007, with regular herbicide spraying from 2010.

The project will continue with spraying and undertake aerial surveys. It has been noticed that the weed has entered off line waterbodies after flooding events. Therefore we will also be contacting the owners of these waterbodies to highlight the presence of this invasive weed to see how these waterbodies can be tackled. Continue to spray on the Barrow Gravel Pits SSSI which will address one of its reasons for being in unfavourable condition.

Monitoring surveys and results

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On a comparable length of watercourse that has been included in all surveys since 2007 (as the survey area has increased over the years) the approximate length of pennywort beds totalled 10.3km in 2009 and 1.6km in 2012, this is a significant decrease in the occurrence of this species.

We are already seeing the impacts of our work. Huge areas are now clear of Pennywort and the river is visible again. We have seen water lilies return in Abbey Park and fish are able to migrate as the water column is clear of the plant. Clearing the Grand Union Canal has made it much more accessible for boats.

Lessons learnt

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This is a constant battle, it is something that needs to be undertaken each year. There was no action in 2008 and this saw a huge increase in the presence of pennywort. As the occurrence of the plant becomes less the time and cost associated with the project also decreases.

Image gallery

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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 Humber River basin Soar Subcatchment River name River Soar from River Sence to River Wreake Area category 100 - 1000 km² Area (km2) Maximum altitude category 100 - 200 m Maximum altitude (m) 116116 m <br />0.116 km <br />11,600 cm <br /> Dominant geology Calcareous Ecoregion Great Britain Dominant land cover Suburban Waterbody ID GB104028047030 Site Edit site Name WFD water body codes GB104028047030 WFD (national) typology WFD water body name River Soar from River Sence to River Wreake 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) 9600096,000 m <br />96 km <br />9,600,000 cm <br /> Project started Works started 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 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 Biology Physico-chemical Other reasons for the project Measures Edit Measures Structural measures Bank/bed modifications Floodplain / River corridor 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