PLANNERS are being asked to approve a major new flood defence project which will help protect 225 homes at Penketh under threat of flooding caused by climate change.
The Environment Agency is seeking Full Planning Major for a Proposed Flood Risk Management Scheme (FRMS) to manage the flood risk along the Penketh Brook, Whittle Brook culvert works & Tidal Outfall and Widnes Road Culvert
Warrington planners are recommending approval for the application stating it would have a beneficial impact upon flood risk for 225 residential properties in
the local area.
The living conditions of adjacent occupiers would be protected from undue harm and the proposal will not have an unacceptable impact upon the local highway network or cause any ecological issues.
The application covers land bounded by Shoreham Drive, Lytham Close and South of the Transpennine Trail (Whittle Brook works) Penketh Brook works south of Penketh Hall Nook and land bounded by Farnworth Road and Widnes Road, Penketh.
The application site includes parts of the Penketh and Whittle Brooks which are located on the western edge of Warrington. The Penketh Brook is a minor watercourse that runs from the North West through multiple culverted sections before opening along Hall Nook and
then culverted beneath St Helen’s Canal and the Fiddler’s Ferry railway line. The open channel then runs south from the Fiddler’s Ferry railway embankment and outfalls into the
Penketh Tidal Outfall. The Whittle Brook runs through an open channel from north to south beneath the St Helen’s Canal and Fiddler’s Ferry railway line, outfalling through the Whittle
Tidal Outfall into the Sankey Brook. There are currently no formal defences along either of these watercourses which flow into the River Mersey to the south of the application site.
The application site measures 5.88ha and is split into four sections where works are proposed:
• Widnes Road Trash Screen: located north of the A562 Widnes Road and south of Farnworth Road, adjacent to the roundabout. The land is a mixture of grassland and vegetation, bounded to the north, south and west by carriageway and by residential housing to the east.
• Penketh Brook Culvert Works: located at the end of Hall Nook, works will cross beneath Fiddler’s Ferry railway line and St Helens Canal. The land is predominantly covered with grassland and vegetation.
Residential housing is present on the north side of St Helens canal and Gatewarth Landfill site is present south of the canal. This area of the site is designated as Green Belt.
• Whittle Brook Silt Clearance Works: located north of St Helens Canal between Lytham Close and Shoreham Drive. The site comprises of grassland with residential housing to the east and west and Fiddlers Ferry railway and St Helens Canal to the south.
• Whittle Brook Tidal Outfall Works: located south of St Helens Canal and north of the River Mersey. The land at this site comprises grassland and vegetation and is designated as Green Belt.
The works will involve:
• Widnes Road – a replacement trash screen including replacement of existing head wall and trash screen and vegetation clearing;
• Culvert Works to Penketh Brook including vegetation clearance and creation of a new 1.8, diameter culvert under the railway line. This will allow the proposed flood relief culvert to operate when water levels in the Penketh Brook rise. The water will flow through a culvert running west along the edge of the track at the southern end of the
agricultural field. The culvert will cross over a surface water pipe and rising main before crossing under the railway and canal in an inverted siphon. To the south of the canal and railway the flood water will flood through a channel and outflow into the Penketh
Brook.
• Whittle Brook – re-profiling works to remove silt deposits.
• Whittle Brook tidal outfall – this is the construction of a tidal outfall structure at the convergence of the Whittle Brook and Sankey Brook. This involves the removal of the
existing barrier and the insertion of a new guardrail that is 1.1 m high. The tidal outfall is below the natural land level. The design also allows provision for maintenance access and eel passage.
The applicants contend that both Penketh and Whittle Brooks have a history of flooding and the frequency and magnitude of this will increase in the future due to Climate Change.
The scheme is proposed to protect against a 1 in 75 year flood and will remove 225 residential properties from the ‘very significant’ flood risk band.
The application also includes landscaping to offset any loss of biodiversity as a result of the proposals.
The applicants undertook public consultation in October 2018 and following this consultation an amended scheme was formatted and a second public consultation was undertaken on the current proposal between 21st December 2020 and 15th January 2021 and as part of that all consultation responses from interested parties were responded to.
There have been four objections questioning the requirement to install a trash screen in Penketh Brook.
Objectors also say trees shouldn’t be removed from site as they limit flooding.
They also claim Penketh Brook rarely overflows and they do not consider that the proposal would help flooding upstream or downstream.
Members of the planning committee will consider the application this Wednesday.
