Case study:Castle Irwell Urban Wetland
Project overview
| Status | Complete |
|---|---|
| Project web site | |
| Themes | Flood risk management, Habitat and biodiversity, Social benefits, Urban |
| Country | England |
| Main contact forename | Gary |
| Main contact surname | Morris |
| Main contact user ID | User:Gjmorris |
| Contact organisation | Environment Agency |
| Contact organisation web site | http://https://www.gov.uk/government/organisations/environment-agency |
| Partner organisations | |
| Parent multi-site project | |
| This is a parent project encompassing the following projects |
No |
Project summary
There is a well recorded history of flooding in Salford from the River Irwell, with the most severe events occurring in 1866 and 1946 and more recently in 2008 & 2015. Therefore there was a need to improve the standard of flood protection from a 1 in 75 to a 1 in 100 year standard. The only remaining area of greenspace to accommodate such a scheme was on the Castle Irwell site.
To undertake this innovative project the Environment Agency worked in partnership with Salford Council and University of Salford, to design and construct a new flood storage basin to better protect 1,900 homes and businesses, but also create a multifunctional recreational space including new urban wetland in heart of Salford.
The site is set on a large meander loop of the River Irwell in an urban area of Lower Kersal just 2.8km from Manchester city centre. As a former recreation site, it was an oasis of green in a largely urban environment, but had limited wildlife value.
Appraisal and design work started in January 2013 with construction beginning in 2015. The flood basin and wetland will be fully operational by June 2017 at a cost of approximately £9 million.
Working with local community, the University of Salford, Salford City Council, the Environment Agency identified an opportunity to work together to use land owned by University and Council to create a new flood basin to help reduce flood risk to people and property just downstream, but also create a new urban wildlife asset in the heart of city, interlinking with neighbouring River Irwell local wildlife site and Kersal Dale Local Nature Reserve on opposite bank.
Once the overall joint agreement for construction of new flood basin and wetland was agreed with all parties, and initial meetings with local community groups to seek their views, the Agency brought in the expertise of the Wildfowl and Wetlands Trust to help develop detailed designs and maintenance plan for new 5.5Ha urban wetland
Community involvement - Community consultation, Community Events, River open days; River Walks; Bioblitz event; Education events, School Tours.
Monitoring surveys and results
The overall scheme has an integrated maintenance and management plan, while wetland has separate maintenance and management plan written by Wildfowl & Wetlands Trust and with prime focus of this being simplicity of management. With both plans integrated as part of site’s long term maintenance, this will ensure as the site develops and establishes, appropriate management will be conducted by agreed respective parties, to ensure in the long term the flood basin remains a functioning flood risk asset, but also an important new local wildlife and amenity resource for future.
Fixed point photography overlooking the new wetland has been installed on neighbouring flats which will monitor the establishment of newly constructed scheme.
The new wetland is also attracting interest from local monitoring groups, including Greater Manchester birders through Winter Wetland Bird Blitz organized by Greater Manchester Ecology Unit and results will be updated to the Greater Manchester Records Centre.
The University of Salford are also keen to monitor the wetland as part of their future courses for environmental studies.
Lessons learnt
Some of the issues faced as part of project was to show it was feasible to construct a new wetland within an Agency flood basin without undermining it’s integrity and primary function, and ensuring the wetland had sufficient water to support the varied priority wetland habitats sought. This was achieved by undertaking groundwater monitoring and ground investigations, with results fed back into design.
Another essential element of the wetland design was to ensure that it would be relatively simple to manage, i.e., by ensuring good vehicular access, and ensuring new wetland habitats were easily maintainable by local conservation groups and council, and reduced risk of competition between wetland habitat types.
The urban wetland is located in the lower Irwell; a catchment that has significant infestations of invasive non-native species. Therefore an invasive control programme was essential, and integrated as part of construction works. Also a long term monitoring and control programme will be adopted as part of overall capital scheme maintenance.
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Cost for project phases
Supplementary funding informationWorking with local community, the University of Salford, Salford City Council, the Environment Agency identified an opportunity to work together to use land owned by University and Council to create a new flood basin to help reduce flood risk to people and property just downstream, but also create a new urban wildlife asset in the heart of city.
Reasons for river restoration
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MonitoringHydromorphological quality elements
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Any other monitoring, e.g. social, economic
Monitoring documents
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Supplementary InformationEdit Supplementary Information
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