As the Lead Local Flood Authority, we are committed to the delivery of flood improvement works to vulnerable communities in Devon.
In partnership with other risk management authorities such as district councils, the Environment Agency, South West Water and Devon Highways, we look for synergies and overlaps in order to ensure that flood risk is investigated and resolved in a coordinated manner where possible.
Where a flood risk has been identified, we work with our consultants and design teams to investigate, optioneer and promote effective options that fit within achievable funding opportunities. Depending on the source and extent of flood risk, the options and form of new defences can vary. These range from ‘hard’ engineering measures such as new culverts, flood relief channels, flood walls and embankments, to ‘soft’ engineering measures, known as Natural Flood Management. These Natural Flood Management techniques aim to slow the flow in the upper catchments such as woody debris dams, field buffer strips and soil management. These more natural measures can stand alone, or support and enhance a hard engineering scheme. Where significant improvements cannot be installed, properties at risk can be supplied with Property Level Resilience measures such as flood doors, boards, airbrick covers and non-return valves in order to limit the impact of flood water coming into contact with the building.
Funding for flood risk management schemes can be obtained from various sources, these include Devon’s allocated budget toward flood improvement measures, the Regional Flood and Coastal Committee administered Local Levy pot, contributions from other Risk Management Authorities, private contributions from local businesses/property owners benefitting from the scheme and Flood Defence Grant in Aid funding allocated by HM Treasury and administered by the Environment Agency. The current national funding mechanism stipulates the requirement of partnership funding toward Flood Defence Grant in Aid funded works; and as part of the role DCC perform, we will approach affected stakeholders in order to coordinate contributions and produce business case documents to support flood defence scheme applications.
As part of the Local Flood Risk Management Strategy, each year DCC allocate funding to support flood scheme development and delivery throughout the County, forming part of the Action Plan approved by cabinet members. This gives authority for money to be spent in those locations deemed high priority and most at risk as well as give the flexibility to promote works in a location where the opportunity arises.
Flood Risk Management Schemes 2018/19
During 2018/19 Devon County Council has been working to deliver the 2018/19 Flood Risk Management Action Plan. Many schemes are ongoing and will be continue to be delivered in 2019/20. See below for an update on the progress of various schemes:
DCC has an input in flood schemes over a number of locations throughout the County. This includes contributions to works by others, investigations and physical improvement works. All of DCCs current schemes and their progress can be viewed on the DCC Environment Viewer interactive map. Individual case studies can be accessed below.
Devon County Council, working with partners Exeter City Council, South West Water, Network Rail and the Environment Agency produced a Surface Water Management Plan (SWMP) document for Exeter. The SWMP identified those areas in the City that were at greatest risk of flooding from surface water and ordinary water courses. The study identified that areas in Beacon Heath and Whipton were at significant rick of flooding. Subsequently DCC has been promoting works in these areas that will look to give betterment to 50 residential properties.
The delivery of the Northbrook upper scheme will take place in two phases over between spring 2019 and summer 2020.
Phase 1- Five linear drainage channels will be installed to capture surface water flows and discharge into the Northbrook watercourse in the Guinevere Way area of Beacon Heath at a restricted rate so as not to increase flood risk downstream. Work will also take place along the footpath to the west of St James School to capture and deflect surface water flows from surrounding roads in the area away from residential properties.
Phase 2- South of the railway in Hamlin Lane Playing fields an above ground water storage area will be created, to attenuate predicted surface water flows in the area to reduce the risk of flooding. This bund will discharge back into the drainage system and into the watercourse at a controlled rate.
Following the repeated flooding in the Woodlands area of Ivybridge since 2012 South Hams District Council investigated the source of flooding and the potential solutions to alleviate it. Following the retirement of the SHDC engineer the scheme was passed to DCC to progress and deliver.
The flood alleviation works aim to convey overland flood flows downstream of the area at risk of flooding in order to significantly reduce the flood risk to 76 residential properties and have been estimated to cost in the region of £650,000.
This will be achieved by a combination of Natural Flood Management (NFM) and traditional defences. The NFM elements of the scheme are located at Hanger Down 1km north of the area that will benefit. A cascade of leaky dams will be installed in a ditch that becomes the means of conveying water during extreme rainfall. The leaky dams will slow and store this flow to reduce the impact downstream. This part of the work is being undertaken in conjunction with the Environment Agency and the Dartmoor Headwaters Project.
In addition to this the existing culverted watercourse system through Ivybridge will be upsized by installing a 130m long 750mm diameter culvert going from Stibbs Lane down through the residential area of Claymans Pathway and Slipperstone Drive to discharge into an existing watercourse to the south.
A new swale has already been constructed in Woodlands Park to the south in order to intercept out of bank flows from the local watercourse and surface water locally.
The work will be funded by Devon County Council, SHDC, Local Levy and Flood Risk Grant in Aid and is due to be completed in the winter of 2019.
Working with the local parish council, a scheme has been developed following flooding that occurred during the winter of 2012/13 in which overland runoff of silt-ladened water flooded 12 properties internally. The whole scheme includes several elements of re-directing surface water run-off.
Phase 1 involved the installation of a large drainage grid which collects surface water and discharges under the highway through a new culvert. The construction of the new culvert running under the A379 was completed in February 2019 and will discharge surface water directly into the Salcombe and Kingsbridge estuary just south of the highway. Designs had to go through Natural England for approval since the Salcombe and Kingsbridge estuary is a designates Site of Special Scientific Interest.
Phase 2 is due to be carried out during the summer of 2019 and will involve directing the flow of water into the newly installed drainage grid from the above fields and working with landowners and the local community.
Following a Surface Water Management Plan (SWMP) produced by DCC in partnership with East Devon District Council, South West Water and the Environment Agency, a scheme has been developed that will improve the standard to flood protection from surface water to over 100 residential and commercial properties. The delivery of the scheme will take place in two phases between autumn 2019 and summer 2020 and is estimated to cost in the region of £750,000.
Phase 1 – Starting in 2019 a large diameter drainage system will be installed in the town centre to better drain the area following intense rainfall. This will then be discharge back into the River Sid. Bypassing the areas at risk.
Phase 2 – Linear drainage channels will also be installed at Station Road and Broadway junction collecting the overland flows from this area. These channels will discharge into a bunded storage area within The Knowle grounds. Water will be discharged from the bund and into the drainage system at a controlled rate so not to increase risk downstream.