Introduction
The Environment Agency and Somerset Council have been working together for several years to develop proposals for a Tidal Barrier Scheme on the River Parrett, to protect Bridgwater and the surrounding communities from flooding.
The Scheme will reduce tidal flood risk to 11,300 homes and 1,500 businesses. The whole scheme comprises of:
- A Tidal Barrier structure on the River Parrett next to Express Park, Bridgwater.
- A substantial programme of works to improve existing downstream riverside flood banks and construct new secondary flood banks.
- Improved fish and eel passage at 12 upstream sites on both the rivers Parrett and Tone.
We are pleased to confirm that the Secretary of State
(Defra)
, having considered the details of the scheme and all the representations made by interested parties and members of the public, has determined to make a Transport and Works Act Order (TWAO) to authorise construction, operation, and maintenance of the scheme.
What this means for the Bridgwater Tidal Barrier scheme
This is a major milestone for the Scheme and means we can now move forward to detailed design and construction of the barrier and its associated elements. The project is large and complex and there is still a great deal of work to be carried out ahead of construction. We are now moving into the detailed design phase and this includes:
- developing the outline design into a detailed design
- technical reviews
- updating environmental assessment and mitigation
- selecting construction contractors
- working details through with landowners
- satisfying requirements of legal consent
- confirming financial arrangements with partners, Defra and the Treasury.
We are pleased that work on the Scheme has been able to progress over the past 2 years, despite the challenges that Covid-19 presents to the government and the nation. We remain reliant on the assistance of several other organisations to maintain progress including determining other necessary consents and licences. We have received approval for the Outline Business Case from the Treasury which is another step forward in the programme.
We can now develop our delivery programme in line with Transport and Works Act Order, planning and environmental constraints together with funding approval. We anticipate starting construction in autumn 2022 with site establishment and then enabling work in spring 2023 and it is likely to take around 4 to 6 years to complete all elements of the scheme.
With the change in climate, it is important that we address the predicted long-term flood risk to Bridgwater and we are pleased the Transport and Works Act Order decision allows us to move forward. The Environment Agency is committed to being Net Zero Carbon by 2030 and the scheme design, delivery and operation will focus on minimising carbon which includes the programme and timing of works.
Update
By the end of the year the detailed design will be complete. We have started enabling works for the barrier and downstream defences. In 2024, construction will begin on the temporary by-pass channel and barrier foundations. Construction of the western access track (to be known as Barrier Way) is near completion. This track will act as the main route for all construction traffic to the barrier site and associated Chilton Trinity downstream defences, thus reducing impact to the community in Chilton Trinity.
This is in line with the traffic management plan that is publicly available. We will be undertaking test piling works in September. This will allow us to confirm and finalise the design. Additionally it will allow us to understand the noise and vibration impacts and how we can deliver the piling works efficiently, when they are required later in the programme. During the test pile, we expect the impact of noise and vibration to be higher than the level experienced during construction. We’ll be monitoring throughout as we work to establish the most effective mitigation to employ during the main works. The test pile will take several days to set up, our subcontractor will arrive on site in early September. When we have more certainty on an exact start date of these works, we’ll contact those who will be most affected.
For more information on the scheme, visit the Environment Agency Wessex Facebook page or email Bridgwater.Barrier@environment-agency.gov.uk
Bridgwater Tidal Barrier Newsletter
Project background
The flooding in early 2014 led a partnership of key authorities to prepare a ’20 Year Flood Action Plan’. The Plan has a clear objective of building a barrier to protect Bridgwater by 2024. The Environment Agency is working in partnership with Somerset Council and is supported by the Somerset Rivers Authority (SRA) and the Local Enterprise Partnership (LEP).
The current flood defences for Bridgwater protect 11,500 homes and 1,500 businesses in the local area. Previous investigations concluded that the best approach from a flood risk management perspective was to maintain the existing defences, before supplementing them at some point with a barrier constructed somewhere between Chilton Trinity and Dunball.
The flood events since 2012 together with a review of technical reports support previous findings that a tidal surge barrier would provide long-term tidal flood protection and has the best prospect of being delivered. This type of barrier is designed to close when required to exclude extreme tides, similar to the Thames Barrier. The construction of any tidal barrier in the Parrett estuary will be a large and complex project that requires careful planning.
The Bridgwater tidal barrier and downstream defence works are important to support the sustainable growth and development of the town and to build business confidence. The barrier will be a large structure across the River Parrett between Express Park and Chilton Trinity. It will have two ‘vertical lift’ gates that would be closed when a very high tide is expected to prevent the tide from travelling upstream and overtopping defences and flooding property and infrastructure.
Downstream of the barrier the existing flood defences on either side of the River Parrett will be maintained or raised to ensure that the barrier is not bypassed by flows in the floodplain and that flood risk is not increased to property and agricultural land. A second set of banks will also be provided at the edges of the floodplain.
The barrier and the downstream defences are large construction projects. As such, whilst we are working hard to minimise impacts, there will be some disruption.
Accessing the full documentation
To access all the documentation please view the Council’s planning online pages where you can access all material relating to the development.