New flood defence structures for Creekmoor and Sterte Channels, housing tidal valves to prevent tidal water travelling back up the channels during high tides.
Lead Authority
BCP Council
Working with
Project start date
26 March 2018
Project completed
23 July 2018
The Creekmoor Channel
The Creekmoor Channel
The Sterte Channel
Project Overview
New flood defence structures have been constructed at the end of the Creekmoor and Sterte Channels where they meet Holes Bay. The structures house tidal valves which will prevent tidal water travelling back up the channels during high tides. Ground levels around the structures have also be raised using recycled soil to continue the line of flood defences in these areas.
- The works at Creekmoor started early April 2018 and were completed, to schedule, on 30th May.
- The works at Sterte followed the Creekmoor project, starting on 30th May and completed, also to schedule, on 23rd July.
- Progress reports & flood defence design information can be found below.
Poole Council worked with the Environment Agency and Wessex Water to secure funding of some £700,000 to deliver these flood defences. The work was carried out on behalf of Poole Council by Avon Construction Ltd.
Creekmoor channel project
The structure across the mouth of the channel is constructed from two rows of sheet piles driven into the seabed and filled with concrete.
The flood defence structure here forms a bridge with foot/cycle way across the channel, an improvement on the previous route that took pedestrians & cyclists via a ‘dog-leg’ close to the busy Upton Bypass.
Please click on an image to open the gallery for a description of each photograph
View of Creekmoor channel looking out into Holes Bay
View of Creekmoor channel looking out into Holes Bay
Layout of flood defences at Creekmoor
Layout of flood defences at Creekmoor
18.04.18 The team from Avon Construction working at the channel mouth
The team from Avon Construction working at the channel mouth
18.04.18 Piles have been driven into the channel bed and the pipes that will hold the valves have been installed. Once the water is pumped out the defences can be filled with concrete.
Piles have been driven into the channel bed and the pipes that will hold the valves have been installed. Once the water is pumped out the defences can be filled with concrete.
18.04.18 Concrete is placed inside the structure and raked flat to ensure uniform coverage with no voids created. It is also important to ensure no concrete seeps out to pollute the channel or Holes Bay.
Concrete is placed inside the structure and raked flat to ensure uniform coverage with no voids created, whilst taking care no concrete seeps out to pollute the channel or Holes Bay.
20.04.18 Waiting for the concrete to harden. Once completed walkers and cyclists will be able to use this structure as a crossing, cutting out the existing ‘dog-leg’ route.
Waiting for the concrete to harden. Once completed walkers and cyclists will be able to use this structure as a crossing, cutting out the existing ‘dog-leg’ route.
01.05.18 Creating the structures that will support the railings to either side of the new cycleway bridge
Creating the structures that will support the railings to either side of the new cycleway bridge
01.05.18 The concrete fill is poured slowly, ensuring an even distribution with no air pockets to affect the strength of the structure
The concrete fill is poured slowly, ensuring an even distribution with no air pockets to affect the strength of the structure
03.05.18 Once set the formwork is removed; the concrete now needs to ‘cure’ for increase durability
Once set the formwork is removed; the concrete now needs to ‘cure’ for increase durability
03.05.18 The base layer for the new pathway across the channel, allowing pedestrians & cyclists to keep away from the busy road
The base layer for the new pathway across the channel, allowing pedestrians & cyclists to keep away from the busy road
23.05.18 The new tidal valves are lowered into place …
The new tidal valves are lowered into place …
23.05.18 … and fitted within the flood prevention structure
… and fitted within the flood prevention structure
31.05.18 A few finishing touches still needed, but the old pathway has been removed, the new access across the channel has been surfaced and it is open for all to use.
A few finishing touches still needed, but the old pathway has been removed, the new access across the channel has been surfaced and it is open for all to use.
A ‘fish friendly valve’ is included in the Creekmoor structure to ensure eels are not restricted in their migratory movement through the surface water system from Holes Bay to waterbodies upstream, e.g. Creekmoor & Millfield ponds. There is no evidence to suggest fish or eels use Sterte channel. This is because it has a concrete base and sheet pile walls, as well as a pumping station which restricts any movements upstream.
Sterte channel project
The structure across the mouth of the channel is constructed from two rows of sheet piles placed on to the existing concrete base, and filled with concrete.
Please click on an image to open the gallery for a description of each photograph
View of Sterte channel looking out into Holes Bay
View of Sterte channel looking out into Holes Bay
Layout of flood defences at Sterte
Layout of flood defences at Sterte
07.06.18 Works starts at the mouth of the Sterte channel
Works starts at the mouth of the Sterte channel
07.06.18 The first stage of the construction of the flood defence is to secure the piles in the channel
The first stage of the construction of the flood defence is to secure the piles in the channel
12.06.18 A second line of piles is now erected
A second line of piles is now erected
Once this pipe which will contain the flood valve is installed in the channel the concrete will be poured between the two lines of piles
Once this pipe which will contain the flood valve is installed in the channel the concrete will be poured between the two lines of piles.
18.06.18 The pipes are in and concrete has been poured between the two lines of piles in the channel
The pipes are in and concrete has been poured between the two lines of piles in the channel
20.06.18 Shuttering is placed around the ends of the pipes so concrete can be poured to create a protective surround for the pipes
Shuttering is placed around the ends of the pipes so concrete can be poured to create a protective surround for the pipes
21.06.18 The shuttering is removed to reveal the protective concrete surround
The shuttering is removed to reveal the protective concrete surround
26.06.18 One of the flood valve’s being lifted into place
One of the flood valve’s being lifted into place
03.07.18 The path has been relaid at a higher level so it becomes part of the flood protection structure
The path has been relaid at a higher level so it becomes part of the flood protection structure
10.07.18 The path now has it’s tarmac topping
The path now has it’s tarmac topping
A special low nutrient soil will cover the bund and sown with Kidney Vetch to encourage the nearby colonies of Small Blue butterfly to colonise the area.
A special low nutrient soil will cover the bund and sown with Kidney Vetch to encourage the nearby colonies of Small Blue butterfly to colonise the area.
20.07.18 The geotextile covering will give some protection to the soil and seeds that have been sown while the vegetation is establishing; it’s made from coconut fibre and will naturally rot away in time.
The geotextile covering will give some protection to the soil and seeds that have been sown while the vegetation is establishing; it’s made from coconut fibre and will naturally rot away in time.
20.07.18 Apart from repairing the fence this project is now complete and the pathway has reopened for walkers and cyclists.
Apart from repairing the fence this project is now complete and the pathway has reopened for walkers and cyclists.
Why is the work needed?
It has been recognised that parts of Poole are likely to face a higher risk of flooding due to sea level rise in combination with a more frequent occurrence of wet and stormy weather. This project is one of the defence measures identified to help minimise the flood risk.
References
- Adapting to Climate Change – Advice for Flood and Coastal Erosion Risk Management Authorities, April 2016: www.gov.uk/government/publications/adapting-to-climate-change-for-risk-management-authorities
- UK Climate Projections 2009: ukclimateprojections.metoffice.gov.uk/21684