Bridgwater Tidal Barrier EIA Scoping Opinion – a lack of knowledge, vision or a rubber stamp?

All large infrastructure projects require an assessment of its impact on the environment. The Bridgwater Tidal Barrier is no different and as one of the UK’s first real climate change driven projects it is important that the long term impacts are understood not just the immediate aftermath of the construction process.

Screening and Scoping Opinions (Environmental Impact) Screening is the process of deciding which projects require an Environmental Impact Assessment (EIA). A scoping opinion only considers what information should be included in an EIA.

What we know

  1. Infrastructure projects whether the BTB, the expansion of London’s railways in the 1800s or the construction of the UK’s motorways in the 70’s have well established long term impacts on our environment as society adapts to the change the project imposes on the area. In Bridgwater’s case the planned BTB removes 3 to 400Ha of potentially development land close to Bridgwater and its existing communication links (J23 of the M5). With the topographical constraints imposed by the M5, the railway and the River Parrett the other options for future development are few.
  2. Bridgwater will in the 100 years of the BTB operation continue to expand and grow and a conservative assessment of the additional area of Bridgwater developed for housing and employment will be around 40% of Bridgwater’s current footprint. Bridgwater’s expansion has to go somewhere and it will impact on the environment beyond the immediate area of construction.
  3. The water that will flood onto the the farmland with increasing frequency will be saline and will change the nature of the land destroying valuable freshwater habitat at Chilton Trinity and at Pawlett Ham’s and the ability to grow food.
  4. A warming climate will see the arrival of new species in particular the Asian Tiger Mosquito to existing open water and bringing the inter tidal habitat up to Dunball as proposed by the Parrett Estuary Flood Management Strategy to the edge of Bridgwater’s habitable area threatening the health of people in North Bridgwater, Pawlett, Chilton Trinity and Puriton and the housing developments on King Drive. It is not unreasonable to consider that open water may well be considered in the same way as in other warm climates as being breeding grounds for mosquitoes and a source of the Zika virus and Denge Fever.

What the EIA opinion ignored.

  • The impact of pushing the economic development onto the Quantock Hills
  • The impact of building on the levels to the east of Bridgwater
  • The impact of seawater on the land.
  • Increasing the rate of salt ingress into the land due to retention of saline water in the borrow pits.
  • potential habitat creation for invasive species and the health threat they make to the local population.

The work done in in this document seems to irrationally imagine that

  • Bridgwater does not expand for the next 100 Years
  • Environmental changes will only be driven by sea level rise
  • The environmental impact is only in the immediate area of the scheme

There is a complete lack of appreciation of the what the BTB scheme entails and its impact on the environment. It studious ignores the wider impacts of this scheme and allows the development to move forward with little or no consideration of the impact. It offers no visibility to the public of what impacts may occur in the next 100 years. EIA are by nature speculative and in the case of the BTB scheme the applicants should provide a wider and more comprehensive assessment.

The EIA is simply inadequate and as a consequence make the work done incomplete and questionable in its efficacy. It is a continuation of the lack of vision and understanding of this project, a project that is key to the long term future of Sedgemoor and Bridgwater.








Bridgwater Tidal Barrier; EA submits Planning Application via Transport and Works Act

The Environment Agency has recently submitted its application to build the Bridgwater Tidal Barrier through the Transport and Works Act (TWA). Its rather like a planning application to Sedgemoor District Council but in this case its to the Secretary of State.

The EA TWA submission repeatedly sets out 10 objectives for this scheme and this article examines whether the Barrier we are being sold does what the EA and SDC say is on the tin.

DOES THE BRIDGWATER TIDAL BARRIER MEET ITS OBJECTIVES?

Description

The scheme consists of two elements designed to keep the sea out of Bridgwater town centre for the next 100 years. Dunball and Bristol Road have to take their chances if there is a breach where as Chilton Trinity gets a second level of protection.

Ultimately the EA plan is to hand over the existing downstream fresh water habitat to the sea creating an inter-tidal habitat. The effect will be to bring the coast from the Steart Peninsula up to Dunball converting the existing farmland to mudflats and salt marsh.

The BTB consists of two elements.

  1. 7 miles of improved river banks that will be maintained for 20 years after the construction of the BTB after which that maintenance will cease and the frequency of the saltwater inundation on the land will be allowed with increasing frequency and the freshwater habitat poisoned.

2. A large reinforced concrete structure with two lift gates located in unconventionally inland and exposed to salt water with a large tidal range that causes one of the most corrosive mechanisms for this type of structure.

The EA / SDC / SRA Objectives

These objectives are presented with no basis as to how they were arrived, what the pass fail criteria is and the implications of not meeting the objectives.

  1. Reduce tidal flood risk to the highest number of properties and commercial businesses in Bridgwater and the surrounding are
  2. Reduce tidal flood risk to critical infrastructure and utilities in Bridgwater and the surrounding area
  3. Deliver a scheme that can be adapted for the future effects of climate change.
  4. Align the project with the strategy set out in the PEFRMS (see also Section 2.2).
  5. Align the project with the recommendations set out in the ‘Protecting Bridgwater and the Somerset Levels & Moors from Tidal Flooding, Flood Risk Management Review’ (Black & Veatch, 2014) (see also Section 2.2).
  6. Ensure the design and operation of the scheme aligns with Local Plan policy for development and does not restrict the future development of Bridgwater and the surrounding area.
  7. Ensure the design and operation of the scheme aligns with Local Plan policy for development and does not restrict the future development of Bridgwater and the surrounding area.
  8. Minimise the impact on environmental receptors during the construction and operation of the scheme. Deliver mitigation as required to protect those receptors that may be affected, whilst maximising positive environmental outcomes.
  9. Minimise health, safety and welfare risks associated with the construction, and operation of the scheme.
  10. Identify funding and partnership opportunities and outline any additional work to gain financial contributions.
  11. Develop a sustainable scheme that minimises future operation and maintenance.

The Test

Objective No 3; Deliver a scheme that can be adapted for the future effects of climate change

It is not stated what those effects of climate change are believed to be, the reader is therefore wrongly invited to presume that the only effect will be rising sea level whilst ignoring other potential changes to the environment and what provisions for adaption have been included in the design as the statement implies.

To illustrate that the EA has not met its own objective I have the following observations.

  1. In order to support this statement, there would need to be a set of assumptions and the concept as to how it might be achieved.in order to judge whether the statement was correct, and the objective met . No such statement exists in the submission.
  2. The stated position of the EA/ SDC/ SRA is no pre-investment for a future scheme; there is no plan B or provision in terms of reserving space for the construction of a new barrier behind or in front of the proposed one.
  3. The TWA submission implies that the structure would  be useful beyond its design life of 100 years and quotes a 1:1,000 return period as being available for flood defense. The BTB is a reinforced concrete structure and in the saline (seawater) environment of the River Parrett such structures do not do well and it  is likely that structure would need to be replaced rather than adapted.
  4. The indicated clearance between the barrier gates when lifted  and the underside of the access bridge shows no provision for taller gates needed to accommodate rising sea level beyond the design basis.
  5. The planned abandonment of the downstream River Parrett riverbanks some 20 years after the barrier structure is completed means that  the  secondary flood defenses ultimately become the primary flood defence and the future shoreline close to Bridgwater. Much of these banks particularly  adjacent to the A38 are founded on the near liquid clay that underlay the Somerset Levels. Nearby Cannington Bends with similar ground conditions continues to settle and the submission notes the need for it to be made up every 30 years or so. It is worth noting that the trial embankment test results do not form part of the supporting documentation. Higher banks will increase the risk of settlement or a breach occurring and triggering an event that the scheme is meant to stop.

There is nothing within the TWA submission to support the statement that the objective has been considered, addressed or met.

Objective 7; Ensure the design and operation of the scheme aligns with Local Plan policy for development and does not restrict the future development of Bridgwater and the surrounding area.

Bridgwater if it maintains its present level of growth in housing and employment will need to increase its footprint by 40% during the design life of the BTB. Much of the allocated land in the present Local Plan approved in 2019 is already under development with only the new Gravity Development at Puriton providing substantial employment land. The only other low quality land available for housing and employment , around 1400 acres strategically close to Junction 23 will be used by the BTB as an operational flood plain to take seawater when barrier is in operation.

There is no statement explaining what Objective 7 actually means or how the objective is achieved.

Specifically this proposal


  1. Denies the Bridgwater the economic benefit associated with developing land adjacent to a motorway junction (J23).
  2. Denies Bridgwater the opportunity to build some 5000 houses and supporting employment centers
  3. Forces future housing development to the south west of Bridgwater that will continue to increase the demand on on the A39.
  4. Increases the separation between residential and employment centres with housing moving to the south and employment to the north ans as consequence increasing the amount of commuting and demand on the road system that ultimately restricts economic development.
  5. the SDC 2050 transport strategy shows the Northern Bridgwater Bypass crossing the operational flood plain created by this scheme. Roads creates economic development and the Transport Strategy and BTB appear to have conflicting objective for the land to north of Chilton Trinity.

In summary

The location of the Tidal Barrier ignores the expansion of Bridgwater over the next 100 years showing no consideration for the planned expansion of the town. There is nothing in the BTB submission to indicate what considerations have made. The EA/SDC decision not to commission an Economic Impact Assessment means that statement cannot be substantiated and explains the lack of a coherent position on objective 7. The Objective is clearly not met.

EA blocks early Bridgwater Bypass Route

In October 2019 the EA produced a plan to block off the only remaining early route for a Bridgwater Bypass. Despite being close to the A38 and having no village (Chilton Trinity) to consider material the EA has decided to dig another borrow pit rather than use locally excavated clays, material that is always available as part of local construction works primarily house building. That pit located in the only remaining place is where an early Bridgwater Bypass can go and the river is at its narrowest.

What this borrow pit means is that nothing can happen until EDF finish with the Park and Ride at Dunball.  This pit will see the taxpayer pay for a longer more expensive bridge and wait longer for traffic relief.

Bearing in mind that this borrow pit could be anywhere and is not actually needed as alternative supplies of suitable fill are always available the only logical reason for this location appears to be to ensure that SDC’s flagship Gravity development does not have any immediate competition. If that is not the case SDC councilors need to be explaining why economic opportunities are being blocked on their watch, why we are not building sustainably and not building in the most economical way.

Despite Sedgemoor District Council declaring a climate change emergency (Bill Revans instigation) the Bridgwater Tidal Barrier scheme continues to ignore any attempt to make this scheme sustainable and reduce cost.

Where is the scrutiny of this scheme by councilors?

Where is the sustainability?

What could be a better plan than to dig a very big hole where you might need to build a road?

annotated extract of SDC drawing showing bypass route and borrow pit
Original SDC/EA drawing showing pits to be dug.
SDC 2050 Transport Strategy map