Introduction
The areas of Scotforth, Hala and Bowerham in South Lancaster are heavily urbanised and experience flooding from Burrow Beck (Main River), which flows in a southerly direction throughout the area.
Over 200 properties in the area benefit from Environment Agency (EA) flood warnings and a river level gauge is located along Burrow Beck adjacent to the allotments between Wyresdale Road and Canterbury Avenue. However, Burrow Beck is a Rapid Response Catchment, making it challenging to provide accurate forecasting without over-warning, meaning flooding can occur in between flood warnings.
Flood events have occurred in September 2011, December 2015 and November 2017. More recently two separate flood events occurred less than a week apart in August 2020, during which 20-30 properties experienced flooding. At least one of these flood events was partly attributed to a blockage of the footbridge from Lentworth Drive to Gressingham Drive. The footbridge was removed and replaced with an approach ramp, reducing the risk of future blockage.
Outline of Burrow Beck Catchment
Flood Risk Management Overview
Several partner organisations have been working together to plan and implement better flood risk management in the Burrow Beck catchment. This includes the EA, Lancashire County Council, Lancaster City Council, United Utilities, South Lancaster Flood Action Group and the Lune Rivers Trust.
Following the flooding in August 2020 the EA constructed a temporary flood defence barrier along Lentworth Drive. This defence, comprised of sandbags and visqueen, proved effective in preventing flooding when tested during November 2020. To maintain the structure’s integrity the EA have replaced the components on two occasions.
All associated Risk Management Authorities have continued to operate in their functions as statutory consultees on planning applications, this has included working alongside prospective developers to ensure proposed plans do not result in an increase in flood risk to the Burrow Beck catchment. Eccleston Homes in particular have opted to implement a range of exemplar attenuation measures within their Surface Water Management Plan, including the construction of two flood storage basins and a tiered system of swales across their intended development site off Wyresdale Road. The developments Surface Water Management Plan can be found on the Lancaster City Council Planning Portal using reference 22/00816/FUL.
Lancaster City Council replaced the footbridge crossing Burrow Beck along Cranwell Avenue in Summer 2023, improving access to the adjacent recreation area. The new footbridge sits on new raised abutments which increase the soffit level of the bridge above the Beck. This will increase the channel capacity and reduce the risk of blockage during high flows, reducing the risk of flooding to local residents.
Completed footbridge at Cranwell Avenue
Several other activities have been completed and there are currently two separate capital funded flood risk management schemes, in differing stages of development, that will offer conveyance improvements to Burrow Beck and formalise the existing defence offering protection to the area of Lentworth Drive.
Current Arrangements
The EA maintains over 2.5km of the Main River Burrow Beck channel through Scotforth, which includes maintenance checks, and management of aquatic and riparian vegetation to maintain the conveyance of the channel. These activities are scheduled to happen twice a year, stretching from the point where Burrow Beck Crosses the A6 (downstream point) to where the watercourse meets the junction of Cranwell and Canterbury Avenue (upstream point).
Once a year, Lancaster County Council maintains the embankment (245m in length) situated on the right bank of Burrow Beck along Cranwell Avenue by undertaking grass and vegetation management. The watercourse is perched in this section, meaning it sits above the surrounding land area. The EA recently refurbished and increased the height of the embankment in 2018 and it now provides a Standard of Protection in excess of 1-in 100 (1% AEP).
The EA and relevant stakeholders are also working to design an additional conveyance improvement project which would offer further flood risk reduction to the residents of the Cranwell Avenue area. The planned scheme, costing an estimated £2million, would provide better protection to 56 properties by constructing a linear defence to the rear of properties along Canterbury Avenue stretching up to the Cork Road allotment gardens.
Continued development of this scheme has been made possible due to the availability of the Frequently Flooded Community (FFC) allowance. This funding is available to qualifying schemes where affected communities have experienced flooding to 10 or more properties, on two separate occasions, in the last 10 years. The EA have secured a FFC contribution of £650,000 towards this scheme.
This conveyance improvement scheme plans to address the existing flow path in which floodwater spills into and through the western floodplain along Canterbury Avenue and Cranwell Avenue. Although the exact design of the defence has not been finalised it is intended to offer a 1 in 20-year (5% AEP) standard of protection.
Initially the EA were able to secure funding to assess the feasibility of several solutions, assessing each of these within an Outline Business Case in line with their protocol for developing capital flood defence schemes. The objective of this study was to identify a preferred option, or a combination of options. The preferred option(s) were selected based on their economic viability and fundability as well as their ability to reduce flood risk in a robust, sustainable and acceptable manner.
As part of the next project phase appointed design consultants will work to further define the preferred option. Further investigations of the work site will likely be required to inform design specifications. Once determined a detailed design must then then be produced, along with a Full Business Case for internal approval.
Internal framework restrictions during 2023 have led to unavoidable delays with development of the preferred design and Full Business Case. In the interim period members of the EA project team have continued to engage with affected landowners as well as other local stakeholders relevant to the scheme.
Although it is not possible to provide a definite completion date for the submission of the Full Business Case, as this depends on many variables, it is the EA’s aspiration that the detailed design element will be completed before the end of Autumn 2024. Updates shall continue to be provided to the local community via newsletters and The Flood Hub.
