Following the EA’s 2019 submission of the BTB Transport and Works Act to the Secretary of State the EA has responded directly to a comment made during the public consultation regarding ring fenced funding.
The background to the question is that if the BTB was located further downstream it can act in the same dual operation way as the Thames Barrier stopping tides coming in and creating a temporary reservoir to increase the conveyance of seaward fluvial flows. In 2014 the Thames Barrier closed 9x for tidal flooding and 41x for fluvial flooding clearly indicating the benefits of a dual function structure.
The EA /SDC BTB proposal does not use this dual operation solution; it has only a single Tidal function. Bridgwater is only getting half what the Thames Barrier does.
People have been given to believe that the funding for the BTB could only be used for Tidal defence rather than as a dual use structure where it could also provide some mitigation to a repeat of the 2014 flood as well as addressing rising sea levels. There was a risk Bridgwater would lose the funding if it asked for flexibility.
Submitted Comment (in blue)
The BTB is not designed to improve fluvial conveyance in the River Parrett and
King Sedgemoor Drain. If it was located farther downstream it could operate in
both modes as the Thames barrier does. (it is not understood why the funding is
ring fenced for tidal defence only)
response below is of great importance with regard to the approval of this
scheme as it contradicts the common understanding that the HMG funds promised
in 2014 could not be used for a holistic flood defence solution in Somerset.
The design and the consultations clearly support only the BTB is a single
EA Response (in blue)
The Scheme is not designed to improve fluvial conveyance in the River Parrett and King Sedgemoor Drain. It is designed to provide a tidal barrier with improved downstream flood defences, to exclude extreme surge tides and prevent tidal flooding in Bridgwater. Funding is not ring-fenced as described, but is made available and allocated on the basis of benefits realised.
The EA response indicates a choice was made not to consider pluvial flooding and fluvial conveyance as a key consideration despite that was the 2014 flooding event event caused the BTB to be brought forward in the first place. Had it been a consideration the case for locating the Barrier further downstream would have had considerably more weighting and possibly changed the outcome of the site selection.
also be noted that that the following non tidal benefits have not been
considered or influenced the work done to date.
The EA recently noted at the SRA board meeting on the 6th March that the 20 pumping stations on the Levels are coming to the end of their design life and there is no budget for their replacement.
The EA noted in the September 2016 public consultation that the location of the Barrier a small distance downstream of the KSD outfall to the River Parrett would provide benefits to the river flows.
The benefit of unlocking the KSD outfall providing increased value for money on the planned KSD enhancement have been ignored.
The benefit to the flooding of the Levels and to Somerset towns on the upstream tributaries of the Parrett that could have been taken benefit from this scheme have not been considered or taken into account.
The artificial separation Somerset’s of tidal and pluvial needs makes little economic, engineering or financial sense and this response indicates that it did not need to be considered. We could have had a barrier that protected the south Somerset Levels including Bridgwater from the sea and increased the fluvial capacity allowing more water to moved through the River Parrett and the King Sedgemoor Drain.
There is now a need to find out if this scheme was unnecessarily constrained. It needs to be established that the proposed BTB represents best values for money for the taxpayer and is part of a wider integrated flood defence solution for Somerset and if funding was not a constraint why do we have a single use solution?
Clearly an independent assessment and investigation is required to clarify the true situation and ensure that the scheme is doing what it should be doing and not what EA believes to be the case. Hopefully the Secretary of State will chose to place this project under the light of public scrutiny before making a final decision to ensure what is proposed is fit for purpose.
The relevant extract of the EA letter is reproduced below
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
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.
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.
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.
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.
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?
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.
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.
Reduce tidal flood risk to the highest number of properties and commercial businesses in Bridgwater and the surrounding are
Reduce tidal flood risk to critical infrastructure and utilities in Bridgwater and the surrounding area
Deliver a scheme that can be adapted for the future effects of climate change.
Align the project with the strategy set out in the PEFRMS (see also Section 2.2).
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).
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.
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.
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.
Minimise health, safety and welfare risks associated with the construction, and operation of the scheme.
Identify funding and partnership opportunities and outline any additional work to gain financial contributions.
Develop a sustainable scheme that minimises future operation and maintenance.
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.
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.
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.
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.
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.
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
Denies the Bridgwater the economic benefit associated with developing land adjacent to a motorway junction (J23).
Denies Bridgwater the opportunity to build some 5000 houses and supporting employment centers
Forces future housing development to the south west of Bridgwater that will continue to increase the demand on on the A39.
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.
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.
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.
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?
The impact of wildlife organisations on locally managed flood projects is a concern. They seem to be free to make unsubstantiated statements whilst pursuing their objectives with little public visibility, criticism or professional oversight and it is a growing problem. It is a situation becoming increasingly familiar and yet another example of our growing democratic deficit where minorities impose their ambitions on the majority. The Somerset Levels, the Parrett Estuary and Bridgwater’s need for a flood defence from the sea has brought many of these parties with their own agenda to one location each focusing on what they consider to be important. Bridgwater seems to be well down the list of importance despite the planned construction of the Bridgwater Tidal Barrier. The purpose of this article is to provide an explanation as to how this is happening.
Bridgwater currently builds around 500 houses a year and if that rate continues at even half that rate for the next 100 years we could expect to see the number of houses in Bridgwater rise by 25,000 taking another 700Ha (1,700 acres) of land for housing and a further 300Ha needed for employment. This 1,000Ha’s will see Bridgwater’s existing footprint grow by at least 50%, The 25,000 houses and associated economic development will generate perhaps 300,000m3 of clays and soil waste.
With flat and level land needed for employment land at the old BAE site and at Horsey offer the only other viable employment options to Bridgwater and they are to the northwest. New housing will be forced onto good quality farmland south along the A38 swallowing up North Petherton and eventually meeting Taunton coming the other way and to the west developing the land between Bridgwater and Cannington. Bridgwater will consume its high value agricultural land on the hills as it, like the rest of the country, continues to build our outdated ideas of housing.
Bridgwater will therefore become an even more difficult place to live and work as the gap between residential development and employment continue to grow. Every day a large part of Bridgwater’s population will get up and drive along the A38 and A39 to get to work. Bridgwater will not even start considering a bypass until 2040.
Apart from the normal lack of imagination by planners and developer’s Sedgemoor’s (Bridgwater) greatest problem now appears to be the wildlife and flood pressure groups that seem to take an extreme view in the pursuit of what they consider to be in their interest. They show little tolerance or understanding that people also live on the Levels and in Bridgwater and ignor the EU directives that accept people must come first. The true impact of their objectives is concealed and never addressed.
These organisations also seem immune from any need to consider facts in their statements whilst criticising property developers for the smallest omission. The irony that is they now ape those same commercial organisations in assembling land and changing its use without considering its long term impact on the wider local population and it should be lost on no one.
Some typical examples
The local economic benefits alluded to as part of the original Steart Peninsula planning application remain unproven and therefore represent little tangible benefit to the local population yet quoted as fact by The Severn Vision statements.
This plan will expand the existing saltmarsh by 833% around the Severn Estuary and in Bridgwater’s case large areas of agricultural land removed from food production and converted from a freshwater environment to a saltwater one (intertidal habitat). To date two phases have been completed; The Steart Peninsula and the RSPB reserve (funnded by Bristol Ports) both of which remove economic activity and destroy an existing habitat to create another. A process little different from modern housing development. Whilst an argument might be made on the basis of geography for these two areas to be returned to the sea no such argument exists for the destruction of Pawlett Hams and Chilton Trinity including areas of the SSI.
This is a process promoted by the following organisations
Wildlife and Wetlands
The Wildlife Trusts
Campaign for Rural England (CPRE)
Severn Rivers Trust
With regard to Bridgwater it makes claims regarding carbon savings whilst ignoring the collateral effect of moving Bridgwater’s housing developments onto higher quality agricultural land and increasing commuting distances. Also ignored is the loss of food production on 5,000 acres of land and the transfer of that food production overseas. It is particularly misleading in its statements with regard to Bridgwater providing no supporting evidence as to the negative benefit that it has considered in any balanced and holistic way. It is completely one sided yet already two key elements have been delivered, Steart Peninsula and RSPB reserve. The Bridgwater Tidal Barrier will deliver the southern land at Chilton Trinity and Pawlett Hams .
Bridgwater Tidal Barrier
The Environment Agency and Sedgemoor District Council’s Dec 2018 public consultation made a claim with regard to the lack of any environmental impact of this scheme. The EA and SDC have not considered environmental impacts beyond the immediate area of the scheme despite this scheme imposing restrictions on economic development forcing residential development to the south and west of Bridgwater and employment to the northwest of the town.
It is worth noting that HPC looked at issues far beyond the immediate area of the power plant when it did its enviromental impact assessment.
Environmental Impact Statement
This statement above cannot be true as
Seawater is shown overtopping the river banks onto the existing farmland, the fact that it is seawater is misleading.
The farmland at Chilton Trinity and Pawlett Hams will be poisoned for agriculture through the introduction of saltwater
The existing wildlife that requires a freshwater environment will be destroyed.
The location of the borrow pits, which side of the secondary flood defence, was not shown. The plan to excavate 100,000m3 of material will create a lake of nearly 13 acres that will act as a reservoir for saltwater.
1,400 acres of high quality farmland suitable will be unnecessarily developed invariable towards North Petherton and Cannington as this scheme will convert 1,400 acres of low quality farmland that could have been used to saltmarsh.
100 years of lost food production on 2400 acres of farmland.
100,000m3 of clay will be unnecessarily excavated from the land being protected whilst during the same period 300,000m3 will be produced as waste through normal housing and industrial construction activities.(the secondary flood defences do not need to be completed to the full height during intial construction
Denying economic development in the north-west will increase commuting efforts in the local community generating avoidable C02; the scheme ensures the increased separation of employment areas from housing.
The claims regarding this scheme are questionable at best and the lack of information misleading at worse. The extract from the EA/SDC public display indicates a plan to create a stepping-stones for species that are not identified.
Campaign for Rural England (CPRE)
The CPRE’s support for The Severn Vision that results in the wholesale destruction of a large area of our existing productive landscape and the equivalent of 10 500 acre farms is not what we imagined their core mission to be that says
“We campaign for a beautiful and living countryside. We work to protect, promote and enhance our towns and countryside to make them better places to live, work and enjoy, and to ensure the countryside is protected for now and future generations.”
How allowing saltwater (seawater) onto productive farmland that has taken 500 years to remove the salt from seems a strange way of protecting our countryside.
Somerset’s Wild Trust (SWT)
Another supporter of The Severn Vision.
Somerset’s Wild Trust’s website says
Since the 2013-14 flooding events, the dominant narrative in the floodplains has focussed on hard engineering schemes and dredging to reduce flood risk, overlooking flood risk reduction techniques that work with nature and provide a range of benefits to society. A future is developing where more public money will be spent on fossil fuel intensive dredging and pumping, to further drain the peat soils of the Levels, thus releasing more carbon and exacerbating climate change. As peat is drained, it shrinks, lowering land height and making the area ever more vulnerable to extreme weather. Well-informed debate on the future of Somerset’s low-lying areas in the face of rising sea level is limited, so a further vital part of our work on the Levels is to communicate a more optimistic narrative which gives nature its proper value.
This statement ignores that the Somerset Level’s is an artificial environment that needs regular maintenance and seems to conflate the need to dredge Somerset’s rivers and the need to get pluvial flows from the upper Parrett catchment areas to the sea bypassing the levels storage with an idea that somehow this process is designed to shrink the peat. “A future is developing where more public money will be spent on fossil fuel intensive dredging and pumping, to further drain the peat soils of the Levels, thus releasing more carbon and exacerbating climate change” is a particularly spurious and misleading statement. It sounds like people are secretly pumping water off the levels as some sort of conspiracy.
Anyone with any knowledge of the Levels would know that retaining water levels is just as important to the Levels as draining them. No one is going to drain the peat. Well informed debate requires informed knowledge and that is clearly not the case with this statement by the SWT.
FLAG Flooding on the Levels Action Group
FLAG reflects its single issue origins seemingly taking its position on Somerset’s farming industry geographically from the lands relationship to Moorland and what is best for Moorland.
A post (Nov 2018) supporting Somerset’ s farming industry on the Levels was made by FLAG making Brexit the largest threat to farmers in anticipation of a nonexistent trade deal with the US; no doubt the cause of the 2014 flood and global warming will in time also be subscribed to Brexit.
FLAG’s postion downstream of Moorland at Chilton Trinity and Pawlett Hams is quite different. Flag is altogther less compasionate regarding the farmers there having their land flooded with saltwater to alleviate upstream flooding. Concern is simply dismissed by a statement worthy of Marie Antoinette “let them raise salt beef or lamb”. It completely ignores that the Bridgwater Tidal Barrier has already destroyed land values for 2,400 acres of land and food production we might have gained. Reverse nimbyism seems to apply; as long the flooding is on someone else’s land FLAG appears to be happy whilst refuses even the smallest tacit support for or willingness to consider alternatives tht might have a better outcome for the wider community.
Whilst our wildlife organisations may have started with good intentions what is clear is that many people associated with these organisations simply don’t understand the mechanisms of the Somerset Levels, the impact of what they propose (The Severn Vision) and in most cases don’t care if it doesn’t suit their agenda. They fail to consider that ultimately the economy pays for everything and destroying local economies will ultimately call into question the viability of protecting our environment; the ratepayer maintains the roads used to get to our wildlife sites and will pay or make a significant financial contribution to the cost to the current planned defences and the their subsequent replacements. A case of shooting the goose that lays the Golden Egg of in this case chasing away industry and people.
It is clear that many organisations support the existing proposals to turn the Parrett Estuary into a saltmarsh. The decision by SDC and the EA not to commission an economic impact assessment has allowed those organisations and the Environment Agency to create the worst possible long term economic future as there is no assessment mechanism other than the government investment rules to measure the value of this scheme. Allowing the undermining Somerset’s agricultural industry, wasteful development and not working towards an integrated low energy society is not what we should be doing.
Ahead of the forthcoming last public consultation on the Bridgwater Tidal Barrier (BTB) the rate and tax payers might consider asking what becomes of Bridgwater after the BTB reaches the end of its design life?
The answer is simple.
if there is no barrier capable of keeping the rising sea out there will be no house insurance, no mortgages and Bridgwater the town will not be a viable place to live.
Our present proposed EA flood defence scheme is based on retreating as far back from the sea as we can, it deliberately puts our backs to the wall On one side of the barrier we will ultimately have the inter tidal habitat (the sea) and on the other our housing and industry.
No space is being provided behind the proposed barrier to create another bigger one. As a consequence there will be nowhere to go with a replacement that does not have a huge and unnecessary price tag. There is an irony that land at Chilton Trinity returned to the sea under the present scheme and the planned managed realignment in 2055 will be inadvertently reclaimed under a downstream replacement barrier albeit land now poisoned with salt.
With sea level rise continuing for hundreds of years past the design life of the BTB one would expect that as responsible people we would give some consideration to what happens next. Unfortunately, like so many things in need of fixing and investment we seem content to kick the problem into future refusing even to consider how we might make some provision to help those that follow us.
Many years an Arup engineer called Poul Beckmann wrote the opening sentence of a document with the line “Human nature is that we put off until tomorrow what we should do today”. Never has that been more true today than in Somerset. Somerset’s failure to develop a realistic, affordable and sustainable long-term strategy is unforgivable. It really is time for some of the promises made by our political leadership on this issue to be delivered and people stop making excuses why things cannot be done. Simply working our way through the Somerset 20 years plan and saying the future is not our business is irresponsible and unacceptable.
what was the question?
The SRA was asked “What is the SRA and its partners working assumption for the replacement of the existing scheme and barrier?
The written answer received from the SRA answer is in blue
From day one, the tidal barrier will be designed in such a way that it will still provide a 1 in 1,000-year standard of protection in 2125. The design includes an allowance for climate change up to 2125.
Climate change does not stop in 2125!!!!
1:1,000 sounds good but its just the margin on the starting point and degrades over time. The Dutch use 1;10,000 and maintain it as the level of protection.
The downstream defences will be designed in such a way that they will still provide a 1 in 200-year standard of protection in 2055, with allowance for further adaption for climate change over time.
2055 is important because this is the date from which managed realignment is implemented under Policy 7d39 of the Shoreline Management Plan.
It is to be expected that any piece of infrastructure would need updating after 100 years. We cannot decide now how future generations may wish to live or what their priorities for infrastructure will need to be. This is why, for example, there are plans for the Thames Barrier to be re-built in future decades but decisions on exactly where and what will be required are deliberately being left for later.
Building the barrier in the town as planned does not give those in the future choices but leaves them no choice to but to go downstream and use land we have previously given back to the sea and to abandon the £100M investment the present scheme will have cost.
The response attempts to conflate the need to replace the 1970’s Thames Barrier as a reason not to make provision today for a replacement in Somerset. if you know you have to replace something why would you not plan for the replacement? Its an excuse.
We should be learning the lessons of the past rather than making a virtue of repeating the failures that the SRA reply implies.
The Thames Barrier Myth
The continual portrayal Thames Barrier shown on TV as an iconic single barrier solution is misleading; the barrier is actually part of the Thames Estuary flood defence system comprising not one but eight individual tidal barriers that all shut together. Five of the eight barriers are closer to Bridgwater’s situation than the “Thames Barrier”. They are however where they should be at the mouth of the rivers they defend not 5 miles upstream as with Bridgwater’s Tidal Barrier.
Using the Thames Barrier as an excuse for not planning a replacement in Somerset is particularly disingenuous for a number of reasons.
Nearly 60 years ago when the Thames Barrier was designed climate change was not understood as it is now. There was little provision for sea level rise just the post Ice Age tilt of the south of England to consider.
The Thames Barrier is upstream of what were active docks that had navigation rights in the Thames Estuary.
In Somerset we have a topography in the form of the Polden Hills, Pawlett Hill and Stockland Bristol that we can link and use to our advantage. London does not have such a luxury.
The most frequent use of the Thames Barrier is now the management of fluvial flood water rather than tidal surge. Something Bridgwater is not designed to do.
Sedgemoor District Council is able to reserve space for a bridge over the Parrett south of Dunball should its not be doing the same for a replacement barrier?
The collective response is No ; there is no plan.
The SRA, EA and SDC were conformed as having contributed to the response
Bridgwater Tidal Barrier; the Questions the public need to Ask
Once the question “how will the proposed Bridgwater Tidal Barrier be replaced?” the present scheme simply looks out of date and poor value for money.
The Bridgwater Tidal Barrier is repeating the same mistake as was made with the Thames Barrier system setting it as far upstream as possible. Because of the selected location a replacement would like the Thames Barrier have to go downstream towards Combwich. Confused? We should be.
When you go to public consultation some questions worth asking;
How will the proposed Bridgwater Tidal Barrier be replaced?”
What becomes of Bridgwater after sea level rise exceeds the design basis of the Bridgwater Tidal Barrier?
Why is there no long-term plan or vision for what comes next?
Why is the ratepayer required to provide money to raise river banks money protecting land at Chilton Trinity when the planned sea water flooding will make it of no economic value?
Why is not improving fluvial flow in the river system part of the scheme?
Why did the cost of the scheme almost double after the location was decided on?
The UK has a serious problem with leadership and sustainable construction where flood defence is concerned. There is a profound lack of critical thinking in the delivery of future UK flood defences and an unwillingness by agencies to get their hands dirty at a local level. As a consequence government continues to fail regarding sustainability and value for money; taxpayer funded agencies seem unable or unwilling to work together. It is a situation compounded by wildlife and environmental organisations who have seen an opportunity to gain control of and modify land in much the same way that monasteries such as Glastonbury once did.
Flood defence schemes are invariably seen in terms of a definable project that can be closed rather than the first step of a sustainable long term solution. The protected community needs to live with and manage these schemes for 100’s of years after they are built. Our thinking on delivery is just too short and too expensive when it is a 300 year or so problem and especially when the initial solution only has a 100 year design life; it makes little sense. There is an obvious gap. That gap means that today’s options should at least consider what happens next. Should we really be adopting a solution today requiring the construction of a replacement barrier tomorrow rather than a scheme today that has provision or a plan for extending it already built in? Our current scheme takes planned obsolescence to a new level.
We should not be closing out future options for the generations that follow and we should follow our own rules for sustainable development
Delivery of the Bridgwater Tidal Barrier continues to be an exemplar of non-sustainable thinking. Part of the scheme requires the river banks between the tidal barrier and the village of Combwich to be maintained. The EA’s plan to do this work as part of the barrier construction contract. Material is to be dug from the adjacent protected fields and where a future Northern Bridgwater Bypass might be routed. Sedgemoor District Council (SDC) have protected in the Local Plan a potential crossing point on the River Parrett just south of the A38 roundabout at Dunball.
Clearly excavating Chilton Trinity’s fields and creating a series of salt water pits that creates an ideal future breeding ground for salt marsh breeding mosquito’s is not what people have considered the consequence to be. It is far from impossible that in a generation Chilton Trinity and Combwich may ultimately become uninhabitable because of this excavation process rather than from the increased flood risk. Managing mosquito borne diseases may well become the larger challenge in low lying areas as our climate warms up. It is difficult to see how the EA could contemplate the creation of such a situation.
With whole life costs of the Bridgwater Tidal Barrier reaching £100M for a barrier, secondary banks and the raised river banks; banks that need continual raising means we need to consider modification of the delivery model to get the costs of this project under control.
That whole life cost also ignores the 100 year economic impact, both locally and nationally, of losing 1000’s of acres of productive agricultural land notwithstanding the questionable morality of a food importing country choosing to export more of its food production offshore.
If we are going to build the solution we have we need better and more economic delivery solutions than is currently proposed. We can then at least ameliorate the present situation with a better delivery system.
Brexit allows the modification of the EU water and waste directives that have now been written into UK law. We can now change the way in which we manage waste for the better.
Every year Sedgemoor will build 5-600 houses and the excavation of foundations and drains for each of these houses will create around 15-20m3 of waste material (clay) suitable for re use as bank raising fill material. Sedgemoor’s planned housing developments will create around 9,000m3 per year that currently must be paid for to be disposed of. Housing developers could supply all the material needed to raise the banks. That is sustainable construction.
Over the 100 years life of the barrier there could be as much as 900,000 m3 of material we need to find a home for; material that could be used to build up the banks and preserve the land we have at Chilton Trinity for future generations. Even if the volume is only 10% of the possible amount its probably enough to avoid digging up land at Chilton Trinity.
Under present EA proposals the EA is going to pay landowners for material that other organisations with similar material must pay to dispose of. We are meant to be reducing this sort of activity not making the situation worse.
We simply don’t need to get all the work in place in 2024; we need just enough to maintain the flood defence need and then use local resources to progressively deliver the longer-term solution with a local benefit to the economy. This work could be collectively done by local contractors under the supervision of either the EA or the Drainage Board. There is simply no engineering need for the EA to wantonly and unnecessarily destroy our landscape when cheaper and more sustainable alternatives are available.
NB there is only an intent to continue to raise the river banks
To put this into perspective that recycled material would
build a bank 5m high bank from the Bridgwater Tidal Barrier to Combwich.
raise the banks and build the secondary flood defences up to match climate change.
raise the banks, build the secondary flood defence and start building new defences north from Pawlett Hill towards Highbridge.
Sea Level Rise
Sea level rise is not expected to slow for at least 300 years making both the barrier redundant as the river banks can only be raised perhaps another metre before they overload the poor ground conditions of the Parrett Estuary. Ultimately the long term plan for Chilton Trinity and Pawlett Hams’s will be realised.
The continued conditioning of the population by the EA to passively accept surrender to the sea as the first option for non-London areas of the UK is disingenuous and defeatist and never mind its land we need to grow food on.
At £100M the present solution for the Bridgwater Tidal barrier is clearly neither sustainable or affordable. A situation that needs to be laid at the door of the Government, Somerset Rivers Authority and specifically the EA and Sedgemoor District Council (SDC) who provide joint project oversight. We need
Sustainability in what we do is placed at the centre of our plans
An independent inquiry into how flood defence is being delivered in Somerset.
A peer review of the BTB project into how it has arrived where it has.
The option of building the Bridgwater Tidal Barrier at Combwich was always affordable and as we now see the full whole life cost of the present scheme being made public its clear the best location was never considered.
Combwich would be a conventional location for a tidal barrier as its near the mouth of the River Parrett. Combwich is a unique site that would offer Somerset a long term solution to protecting the southern Levels as a barrier and associated embankment would close the narrow gap between Stockland Bristol and the Polden Hills via Pawlett Hill. The location also offers an appreciable increase in the fluvial conveyance capacity of the existing River Parrett catchment river system.
Original image is courtesy of the British Geological Society.
The yellow colour in the above image is the soft clay deposited around 11,000 years ago. The existing river banks will see the new flood defences from Combwich up to the site of the proposed Bridgwater Tidal Barrier built on this soft material that is up to 20m deep. Defences that due to settlement will need to be built back up every 30-35 years defending land that will have been flooded with saltwater.
The argument is that it’s the cheapest solution where it is in Bridgwater.
People continue to believe the width of the river and the length of the barrier structure is the only driving cost of the scheme. Whilst size does matter it is not all that matters. Like most schemes that start without a clear direction the final cost proves to be significantly more expensive than expected and the Bridgwater Tidal Barrier is no exception. The EA project team didn’t understand its costs just its objective. They are not the same and nor are they aligned with securing Somerset’s long term future.
Most people are aware that present scheme originated from a 2009 scheme that was little more than a knee jerk reaction to climate change and the long-standing need for a control system in the river. What we have seen is that inexperience in project delivery saw the early focus on one element of the scheme rather than the scheme as a whole. Effort was exclusively focused on the barrier, the type of gate and location within a short length of the River Parrett and it clouded objective thinking about an holistic scheme. It was so bad that the EA team doing the barrier were unaware of the test bank being done by the EA and Team Van Oord; there was simply no joined up thinking.
Nobody at that time or since has been willing to stand back and take a cold hard look at what was needed when the Cameron Government’s political promise of post 2014 flood money removed critical thinking from the delivery process.
The simple fact is that every activity has a cost and the choice the client and the designer has is where you spend the money today and tomorrow. A simple comparison of where our money will be spent is produced below. You can spend money on lawyers and land agreements for secondary flood defences or spend the money on a better barrier. Paper does not keep the sea out.
Combwich offers a number of advantages that offset the barriers extra length and the constraints of the present location in Bridgwater. These advantages include the use of precast concrete construction, the availability of space for construction, no need for an expensive diversion channel and the long periods when the river is empty make considerable cost savings.
The key savings are given below.
a barrier structure could also support a future bypass.
The good thing about the River Parrett and there are very few is that its possible to work on the river bed without the need for a coffer dam. If you have the space and you’re in the infrequently used navigation channel of the Parrett you move and do things in the water during high tide and then drive down the bank onto a prepared river bed. and work during low tide.
The January 2018 news that the estimated cost of the Bridgwater Tidal Barrier (BTB) had reached £100M caused the BBC last week to interview stakeholders at the EA, Sedgemoor and Bridgwater Town Council. Anyone who heard the interviews and knows anything of the history of this project will be as equally concerned as Bridgwater’s Town Council. The risk regarding withdrawal of funding is real; Government will not accept being led on and neither should the ratepayer which is becoming the real story of the Bridgwater Tidal Barrier.
EA and SDC interviews.
The EA chose somewhat disingenuously to blame the hike in price on the Government making a perfectly normal and responsible demand regarding cost information. Information not previously provided to the SDC ratepayer.It was clear during the public consultations (the boards are still available on the SDC website) that the selection method (river width) was flawed in ignoring the cost of the downstream works and the associated maintenance costs that went with them. Cost confusion about this project has been a problem ever since work started on developing options and presenting the options to the public. Previous written responses raised this issue in March 2016 and nothing was done to clarify the situation in subsequent public consultations.
The well known poor ground conditions of the Parrett Estuary were again blamed. Ground conditions have become a convenient hook to hang cost increases on. If the costs associated with ground conditions are being continually underestimated at such a late date there is clearly a management issue that needs to be fixed.
SDC again conflated Cameron’s “never again “statement made in 2014 with the Bridgwater Tidal Barrier. People will continue to imagine that the Bridgwater Tidal Barrier will somehow mitigate a 2014 flood when that isn’t the case.
The reality is that neither the EA’s technical management team, those responsible for providing senior project management/Governance (EA/SDC) or the councillors providing oversight have the necessary experience for a project like this. (£29M was beyond their reach and £100M is farther still and requires experienced management). The BTB was always going to get away from under them as it clearly has.
As a contributor to the EFRA Future Flood Prevention report in 2016 I highlighted the issues that are deeply embedded in this project. Entitled Managing local UK infrastructure; the Client Deficit. it highlighted the lack of an independent adviser to stakeholders as a continuing problem with UK locally managed infrastructure projects, it is a situation repeated elsewhere and in Somerset the SRA is a particularly good example of people being responsible for delivering projects that they are not experienced or qualified to do and not being provided with the support they need. The KSD expansion project seems to be struggling in a similar way to the BTB. Googling ones mobile phone is not a valid substitute for experience nor is having laid a patio in earlier years.
We all now understand that the Bridgwater Tidal Barrier solution (location) was driven solely by the promoted idea that “river width” somehow equated directly to project cost; getting the barrier as far upstream (narrowest point) was the cheapest option for the EA. it was always a flawed strategy and the cost we are now seeing is the result of that approach. It is the result of not doing work that should have been done during the options study. The initial cost of the downstream raising of the river banks and the cost associated with the intent to continue to do so does not appear to have been fully considered in the original location decision.
Unfortunately, valuable and costly time was spent on what sort of gate we should have had rather than looking at the overall solution and there was no challenge to the 2009 B&V spread of locations. Long term costs and the EA’s rather ambiguous position regarding the long term raising of the river banks were conveniently ignored in the 2016 public consultations. Consultations that completely ignored the principles set out in Government guidelines on public consultations.
This situation was compounded by the obvious client project inexperience shown in the rush to engineering studies before an outline plan was agreed that always results in the cost escalation we are seeing. The sudden arrival of the secondary flood defences is something that should have been highlighted in the option studies, it may not have been needed at sites farther downstream and was not shown in the early public consultations. After 30 years of managing the design process on much larger projects than the BTB starting a project without a real plan is always a trap waiting for the unwary. Sadly, as a result of the BTB execution strategy what we now have is less normal project delivery and more an episode of Grand Designs. At least the consultants should avoid any blame.
What was striking in last week’s radio interview was the lack of any new arguments after all the work that has apparently been done to support the scheme in its present form. What is equally impressive is that both the EA and SDC imagine that Bridgwater will not want to grow beyond the line of the barrier over the next 100 years or that a critical piece of infrastructure should be located so close to the town. Shouldn’t someone have asked how big will Bridgwater be in 100 years? The whole BTB project appears to have now deteriorated to the justification of an original poor decision. It is most disappointing.
The information the ratepayer has seen to date raises questions of transparency or competency neither of which seems to have been achieved or available to any degree.
Ratepayers should not be paying for all the people involved in the BTB project and the broader Somerset Flooding issues to be learning on the job which seems to be the case.
Its well past the time that the Bridgwater Tidal Barrier including its location is independently reviewed before it is presented to the ratepayer one last time. Its time we considered moving the Bridgwater Tidal Barrier downstream to Combwich.
The questions of
transparency with regard to cost and economic impact.
management team competency
oversight competency and relevant experience
the approved barrier location
what happens at the end of the 100 year design life; Bridgwater Tidal Barrier 2?
clearly needs to be looked at as the information previously provided to the public and one assumes our councillors did not reach the standards we should expect and was wrong.
Projects do not suddenly almost double in price in 15 months without good reason. The defence of the cost increase presented in the interviews was as unacceptable as the schemeitself has now become.
Sedgemoor District Council and the Environment Agency recently reported at the Somerset Rivers Authority (SRA) meeting in January a 50% increase in the cost of the Bridgwater Tidal Barrier. The reported cost appears to have increased from £70M in October 2017 to £100M in January 2018 (five months) and yet it went through without comment .
The cost escalation of a scheme that does nothing to address the 2014 fluvial flood is eye watering and yet, according to the minutes, no action is taken to explain why this escalation had occurred and what action was being done to mitigate it. The mere acceptance by our elected members is not acceptable if the delivery of our infrastructure is to be managed locally rather than through central government.
Bridgwater Tidal Barrier Cost History
March 2014 the cost of barrier was reported at £26M
September 2016 The EA gave the public figures during a public consultation various options with costs; site 5 the selected site was costed at £45M – £60M.
October 2017 the BBC reported on the cost of the scheme to be in the order of £70M “Bridgwater tidal barrier costs ‘could go up by £10m”
In a period of around 15 months from September 2016 to January 2018 the cost of the Bridgwater Tidal Barrier scheme rose by around £50M or 100% and not one word of concern is expressed or recorded in the public domain. This cost is now nearly 4x the original cost estimate in 2014.
Bridgwater Tidal Barrier is now a £100M scheme where
the financial investment makes no contribution to mitigating a repeating 2014 fluvial flood,
repeated saltwater flooding onto farm land from the River Parrett is seen as being an acceptable regime despite poisoning farmland and wildlife.
there is no plan in place beyond the barriers 100 year design life
brings saltwater onto our agricultural land
Looking at the numbers the only thing that can be concluded is that the cost estimates presented to the public and to councils for the purpose of decision making were widely inaccurate or inconsistent either of which is unacceptable for investment decisions; especially decisions that affect the long term future of Bridgwater and Somerset Levels beyond.
The selection decision of the current site (Site 5) was chosen purely on the basis of the width of the river and must now be called into question. It would appear that the cost of the other downstream elements of the scheme must be causing this cost escalation. A cost and concern that were dismissed at the time of the consultation.
Bridgwater Tidal Barrier is now a £100M scheme where
the financial investment makes no contribution to mitigating a repeating 2014 fluvial flood,
there is no plan in place beyond the barriers 100 year design life
repeated saltwater flooding onto farm land from the River Parrett is seen as being an acceptable regime despite poisoning farmland and wildlife.
the EA wants to dig up the very land its meant to be protecting to win the soil for flood defences.
No project should be seeing this amount of budgetary increase without challenge. Cost escalation on this scale is unacceptable and unnecessary. There is clearly a continuing problem regarding a lack of oversight both technically and financially in this project.
What should be done?
The extra £50M buys a much better scheme than the one Bridgwater is getting. £100M would allow
the barrier to be located as is normal practice as close to the mouth of the river as possible which in this case is Combwich. Combwich was never looked on the basis of cost, clearly that is an argument that can no longer be supported.
elimination of most of the downstream river works that the EA’s tests indicate will need to happen every 35 years or so.
increased fluvial capacity in the River Parrett and the King Sedgmoor Drain potentially benefiting communities beyond Sedgemoor
a solution that can be economically extended beyond the 100 year design life currently offered.
£100M is £1M a year for next 100 years on scheme that will be rendered redundant once the river banks can no longer be raised to combat sea level rise; the scheme in present form is throwing money away
The public expect that those on scrutiny committees to use there position to bring transparency and accountability to the process of public expenditure. Such bringing to account appears to be sadly lacking together with visibility of any independent engineering review that a project of £100M warrants. The project is growing in value and the oversight is not growing with it.
Unfortunately what we see happening is the management of infrastructure projects by people, primarily councillors and officers who are unqualified to do so. The SRA is a prime example of an organisation primarily engaged in the commissioning of engineering activities with no engineers in lead roles. The Bridgwater Tidal Barrier has become a Grand Designs episode of Civil Engineering
A Public Inquiry into the management of the Bridgwater Tidal Barrier scheme should be convened that should look at
Location (including the examination of Combwich)
Competency and experience of councillors and officials to manage civil engineering works such as the Bridgwater Tidal Barrier and other SRA projects.,