Localised flood defence scheme could ‘reduce risk’ to homes
PUBLISHED: 14:43 31 January 2019
(C) Archant Norfolk 2015
Homes vulnerable to flooding could be protected in the future by a 200m wall as part of a major £32.5m scheme.
With a number of areas in Lowestoft vulnerable to surface water flooding, particularly around Kirkley stream, a “localised flood defence scheme” has been proposed.
In July 2015 more than 30 homes in Aldwyck Way and Velda Close were flooded after heavy rainfall – “described as a one in 40-year event” – appeared to overwhelm the stream and drainage systems resulting in significant flooding.
Householders were left distraught after waist-high water flooded 33 homes, with considerable damage caused to areas surrounding the Kirkley stream.
But now relief could be in sight as “a flood alleviation scheme to manage fluvial flood risk in Lowestoft” has been unveiled.
Plans have been submitted to Waveney District Council to construct a “flood defence wall that will sit between the properties on Aldwyck Way and Velda Close and Kirkley Stream, running for approximately 200m from the A1117 Bloodmoor Road roundabout at a maximum height of 1m.”
The application proposes the “construction of a sheet pile wall” along the Kirkley stream from the Bloodmoor roundabout and “continues for around 200m downstream of the roundabout.”
The defences also include a pump station and underground storage facility at Velda Close/Aldwyck Way.
A Waveney District Council spokesman said: “The works are part of the Lowestoft Flood Risk Management Project (FRMP).
“The project aims to reduce the risk of flooding from all sources: from the sea, from river (fluvial) and extreme rainfall (pluvial).
“This element of the project addresses the risk of flooding from river and extreme rainfall.”
With Balfour Beatty the contractor for the Lowestoft FRMP, the project is promoted by Waveney in partnership with Suffolk County Council, the Environment Agency and Anglian Water.
A design access and planning statement produced by Balfour Beatty, on behalf of JBA Consulting, said: “The Lowestoft FRMP has identified that 24 properties in the Velda Close and Aldwyck Way area flood risk can be reduced by a localised flood defence scheme.
“The flood wall will be constructed of sheet piles embedded into the ground. The wall will be screened by a timber fence similar in character to the existing conditions.”
With the plans currently “awaiting decision,” if the scheme is approved, construction would start in September and be completed by summer next year, according to the application.
Lowestoft Flood Risk Management Project background
The Lowestoft Flood Risk Management Project (FRMP) aims to reduce the risk of flooding from the sea, rivers and extreme rainfall.
During the December 2013 tidal surge more than 160 homes and businesses in Lowestoft were flooded, with road and rail networks significantly disrupted.
The £32.5m scheme to reduce flooding in Lowestoft was launched in October 2017.
The project includes the creation of a permanent wall which will be built around the harbour to protect against tidal surges, with a tidal gate located near to the Bascule Bridge to prevent surge water entering Lake Lothing.
A Waveney District Council spokesman said: “We plan to submit a planning application for the construction of the advance works (tidal flood walls) in early spring, with start of construction planned for November this year.
“The tidal barrier is subject to a Transport Works Act Order and that is in progress now.
“The project should then take around two years to complete.”
In December 2013, a tidal surge caused significant flooding Lowestoft, resulting in 158 residential and 233 commercial properties being flooded along with the closure of the A12 through Lowestoft and Lowestoft Railway station.
Suffolk County Council hold records of 67 reports of surface water flooding across Lowestoft since 2013.
In July 2015 a period of heavy rainfall – estimated to be a one in 40-year event – resulted in pluvial and fluvial flooding to 33 homes in Aldwyck
Way and Velda Close with water levels rising to 300mm to 500mm in residents’ main living areas.
This prompted Suffolk County Council to conduct a Section 19 Flood Investigation Report.
Carlton Colville has also experienced several flood incidents with four reports of internal flooding; most significantly in July 2015.
Frequent flooding of The Street at Carlton Colville has also been reported.
Flood Risk Assessment Summary
According to a “flood risk assessment summary,” which forms part of the application, fluvial and pluvial flood risk to Lowestoft “is a result of the complex interaction between surface water sewers and the Kirkley Stream.”
The application states: “Both of these systems can be influenced by the tidal downstream boundary.
“To understand the flood risk to the area an Infoworks Integrated Catchment Model (ICM) was utilised.
“It is estimated that 997 properties across Lowestoft are at risk of pluvial/fluvial flooding, with 297 properties considered to be at ‘Very Significant Risk’ (less than 1 in 20 annual risk of inundation).
“This is estimated to increase to a total of 1076 properties at risk with 328 at ‘Very Significant Risk’ with the impact of climate change.
“The mechanisms for flooding at Velda Close arise from the Kirkley Stream, the surface water drainage network and hydraulic interactions between the two.”
It adds: “The proposal will not increase surface water flood risk elsewhere.”