River Parrett – Page 2 – Steve Trowbridge

18/06/201802/08/2018

Bridgwater Tidal Barrier Cost; an unacceptable defence

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.

Readers can listen to the program on BBC iPlayer for a few weeks. Move the bar along to hear the EA at 40min and SDC is around 140min

The defence of the cost is indefensible.

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 scheme itself has now become.

10/03/201815/03/2018

Bridgwater Tidal Barrier cost reaches £100M

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”
January 2018 indicates the cost is now around £100M as noted below from the published SRA draft minutes.

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

Way forward

A Public Inquiry into the management of the Bridgwater Tidal Barrier scheme should be convened that should look at

Cost
Management
Consultation process
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.,

05/03/201816/08/2018

Environment Agency – Landowner Information Pack

The Environment Agency (EA) like the many political parties with the word Democratic in their title seems ever farther away from what people imagine the organisation to be about. Protecting the Environment and the people seems not to be one of them if it gets in the way of its long term Parrett Estuary agenda at Chilton Trinity north of Bridgwater.

However any doubts that the EA doesn’t have a sense of humour or understands irony was firmly dispelled by its latest offering to the Chilton Trinity landowners. These are landowners whose land is impacted by downstream works resulting from planned construction of the £100M Bridgwater Tidal Barrier close to the town rather than is conventional practice at the mouth of the River Parrett.

In March 2018 each landowner was the recipient of a document called BRIDGWATER TIDAL BARRIER DOWNSTREAM FLOOD DEFENCES Landowner information Pack.

The EA’s apparent lack of understanding of the impact of salt water flooding onto farm land. is worrying. The expected floodwater is not like 2014 when the water that covered the Somerset Levels was predominantly fluvial run off (freshwater). This will be seawater coming up the River Parrett from the Seven Estuary that over tops the river banks.

This document also asks farmer’s to allow the Environment Agency to dig borrow pits in the land the EA are meant to be protecting. Borrow Pits are meant to be refilled with other less suitable soil so it does not lessen traffic as the EA claim but only if they are left as just open pits in which case they aren’t borrow pits. Do we really need to excavate the land we are meant to be protecting?

The alternative is a sustainable construction method that also seems to be a low priority of the EA. Construction of the bank improvements could be phased over a number of years using local contractors and material reclaimed from new developments.

The proposed pits will hold the seawater (saltwater) rather than see it quickly flushed away back to the river. Saltwater is poison to agricultural land and the habitat we currently have in Chilton Trinity. These pits will, according to the trial embankment test done for the Cannington Bends improvement scheme, need to be reopened or enlarged every 35 years of so to make up the levels as the made up river banks settle.

The EA promise going forward regarding maintaining bank levels quite rightly only talks about intent; the EA cannot provide a firm promise however they do know that once the land is poisoned the cost for further expenditure on bank raising will not be justified.

No one can say that the EA does not have a sense of humour especially when the Chilton Trinity farmers are encouraged by the EA to act as turkeys to vote for Christmas. The EA’s long term ambition of an inter tidal habitat remains our pantomime villain – he is behind us and we chose not to look around and see him. Whilst appearing to help the EA are actually creating a self fulfilling prophecy that will see the area become salt marsh.

This document

Only talks about 2024 and not 100 years in the future (2124) which is much more interesting for long term prosperity of everyone including our farmers handing land onto future generations. ( nobody says what happens when the banks can no longer be raised)
Confirms the level of protection they are planning to maintain to farm land is very low.
Omitted the future flood maps.
Omitted to mention that the flood water will be seawater .
Demonstrates on page 4 a complete lack of understanding of the impact of saltwater onto agricultural land. (Some Lincolnshire farmland has still not fully recovered from the 1953 flood when the North Sea over topped the sea defences)
Encourages the formation of borrow pits (actually just pits) that, when the banks of the River Parrett are overtopped, will trap seawater and ultimately destroy the value of the land its meant to protect. Destroying wildlife and fauna in the process that cannot handle saline conditions A case of the medicine killing the patient.
Creates through the use of borrow pits mores areas of stagnant water that in our warming climate will be a breeding ground for insects, one of the reasons given for not damming the River Parrett.
Fails to mention the pits will need to be used and extended at least 3x as according to the embankment trial the river banks will need raising every 35 years.
Does not mention the final height of the river banks in 100 years’ time, for every metre raised the bank get wider by 2 x 4.0m and the banks will need to be raised by around 0.80m. (2’6″) excluding the continued settlement of the river banks that always means 2 steps forward and always 1 step back.
Re-confirms that agricultural land will be preferentially flooded.
The EA commitment is qualified as only an “intent” . Will SDC ratepayers pay for the maintenance when they don’t get anything back? It’s a huge liability that SDC could end up with that has no benefit to the town. In a very short period of time, the cost of maintaining river banks to protect a small area of land and some ponds (flooded borrow pits) will not be considered worthwhile.

No one can say we were not warned about this EA scheme and still no one asks what happens after the proposed scheme, the Bridgwater Tidal Barrier, can no longer counter rising sea levels?

One can only appreciate the irony and the humour of the situation along with the EA’s other recent bits of entertainment

The gathering up the local newt population at Steart and their subsequent disappearance
Diverting migrating elvers away from their normal route to our freshwater river system into the Steart Peninsula scheme.
Planning to build a tidal barrier as far inland and upstream as possible contrary to all normal accepted good practice.

to paraphrase Churchill

never has so much money been spent in such a small place to so little effect

This document is at best poorly put together and at worst a device designed to obscure the true impact of the plan from those most affected

As this slow-motion environmental, and for Bridgwater, and economic car crash occurs we should not forget that three prominent members of the Wessex Regional Flood and Coastal Committee live within a mile or so of where this unnecessary and increasingly misrepresented process is going on. No objection or question is heard regarding the impact of the EA Scheme; there is no visible oversight.

The Internal Drainage Boards are equally silent as is the Somerset Rivers Authority

Finally, you know its wrong when that well-known litmus test is applied; The scheme in its present form has the support Ian Liddell-Grainger

09/10/201719/03/2018

Severn Estuary Forum 2017

The Severn Estuary Forum met for its annual meeting 2017 in Bridgwater, Somerset on the 5th October following hard on the heels of Question Time and the Antiques Road Show at the McMillian Theatre.

An event to see people working together to resolve climate change, flood risk and wildlife preservation it was not.

Richard Hickmet the High Sheriff of Somerset opened proceedings.

The day was split into three sessions and some notes on the highlights follow.

Energy and Climate Change

Session Chair SDC councillor Ann Fraser MBE introduced the session noting the increased trade (marine aggregates) going through Dunball now rising to 70,000T per year as a reflection of increasing economic trade. Fortunately, Ross Edwards in his following update on Hinkley Point C (HPC) noted that their aggregates jetty being built as part of the enabling works was still underway. The real reason for Dunball’s growth was more to do with HPC immediate need rather than some wider reason. The irony of the councillors assumptive claim was not lost.

Ross Edwards (EDF) was able to explain, whilst maintaining a serious face, the extreme lengths that EDF were going to protect the beach from the small feet of a jack up barge and a few discreet foundations. Yet another large corporate organisation feeling the need to succumb to the irrational demands of the modern environmentalist. He also noted that EDF had spent £20M on road improvements as part of the HPC project enabling works.

Dr Judith Wolf of the National Oceanography Centre in Liverpool provided a fascinating talk that actually dealt with the session subject. The moderating impact of the edge of the continental shelf in dissipating energy should make us all worry a little less about that large piece of a volcano that threatens to slide into the sea in the Canaries at La Palma causing a tsunami. The great flood of 1607 also got a brief note and it was not a tsunami.

What was more important was Dr Wolf’s comments on global warming and the best scenario of sea level rise being 0.5m and the worst at nearly 2.0m. Dr Wolf confirmed they really don’t know the figure as no one knows how the melting polar ice caps will impact on the world. It was received with little or no comment. 2.0m is around twice the figure that the EA is using for the Bridgwater Tidal Barrier (BTB).

Planning Governance & Flood Risk

Andy Hohl (EA) project manager of the Bridgwater Tidal Barrier project explained the mechanism of the floodgates but avoided the mechanism of the planned flood defence system. A diagram was shown showing the planned flooding of Chilton Trinity and Pawlett Ham’s when there is coincident high tides and storm surges. It is an event that will increase in intensity and frequency as sea levels rise and after a few events will have poisoned the land.

River Parrett at Chilton Trinity and Pawlett Hams; EA flood model Bridgwater Tidal Barrier 5th October 2017; How the River Parrett will increasingly flood the Levels

The EA missed the opportunity to explain why a tidal barrier is to be built in Bridgwater rather than the conventional locations at the mouth of rivers such as at Newcastle and Barking.

Mr Hohl was asked what comes after rising sea levels makes the Bridgwater Tidal Barrier ( gate and river banks) ineffective in protecting the area from the sea. Apart from some irrelevant comments about things being done today, there was no answer about tomorrow. Tomorrow, if Dr Wolf is correct, will be only 50 and not 100 years away before a replacement solution is needed.

Wessex Water’s Lucy George gave an interesting talk on the construction of the new sewers being built around Bridgwater. Clever engineering in bad ground.

Protected Sites and Species
Alys Lavers the WWT manager at Steart gave an update on the last 3 years entitled Climate Change, Flood Risk and Community Action. It has obviously become a go to place for students studying for degrees and PHD’s. Even some elver’s have apparently decided it’s a great place deciding that the swim to Oathe and the freshwater rivers of the Tone, Yeo, Parrett and beyond was simply not worth the effort and turned right into the Steart reserve. Whether that was in the EIA and is safer than getting past the locals elvering is no doubt a study in itself. However a look at the IDB asset map apparently showing every route to freshwater blocked by a clyce does not paint a promising future for the lost elvers.

Ms Laver was also remarkably candid about Steart. That there would be no facilities built there apart from the existing toilets. No chance of a place to shelter from the elements and have a cup of tea. Little chance then that Steart will deliver the promised economic contribution when planning permission was sought by the EA. Someone in the audience from Burnham on Sea said it was difficult to find and Ms Laver explained that the lack of signposting was deliberate. Apparently keeping the number of visitors down was done for the benefit of the locals.

What was apparent to many in the audience was that WWT Steart is really only interested in the right sort of visitor; academia and other suitable people. The ordinary taxpayers who paid for Steart from their taxes (that is where the EA get its money from) most definitely not welcome.

Rob Shore WWT, session chairman and coordinator of the Severn Vision introduced the document that was first published in January 2017. What is interesting is the ambition of this recent document. A saltmarsh from Dunball to Highbridge. The proposal outlined in this document is clearly in line with the EA’s and SDC’s current strategies set out in the Shoreline Management Plan and Parrett Estuary Flood Strategy.

The map below was generated from the Severn Vision interactive map. If you live around the Severn Estuary its worth checking out the aspirations of the various wildlife organisations.

One cannot help but feel that the EA and various wildlife organisations including WWT have the ambition to turn the coastal part of Somerset into a wildlife theme park. Trading off the land in Somerset for planning gain elsewhere such the Bristol Ports deal where Bristol gets the economic benefit and people in Somerset beyond made to feel to feel uncomfortable in their own countryside is unacceptable. Climate change should not be used as little more than a Trojan Horse by organisations with an overblown sense of morality and entitlement.

A question on the morality of an island that cannot feed itself flooding food producing farmland to create saltmarsh was quickly pushed to one side.

Finally a question about mitigating the noise from exploding old military ordnance being found as part of the HPC outfall construction work. Ordnance, when located, is subsequently blown up by the Navy’s bomb disposal team; it did not find someone willing and able to answer it.

Observations

What was quite clear was climate change and rising sea level is really only a device and agenda for wildlife organisations to pursue the expansion of wildlife habitat.

There was no big picture presented, no key numbers and no one to provide context as to how the wildlife of the Severn Estuary, ordinary people and business might co-exist. Key local councillors present on all the flood committees, Wessex, the drainage boards and the SRA were with the exception of Ann Fraser notable by their absence. Perhaps there were no expenses paid for attendance. Councillor Fraser it was noted in the Speaker Summaries although not an engineer had been “instrumental in leading a technical review of the flood risk in Bridgwater”. The Somerset Rivers Authority is no better with regard to engineering. There is a disturbing and dangerous precedent of non-qualified people in influential positions shaping Somerset’s flood and climate change plans. Google and mobile phones do not make an expert.

There is simply no leadership or vision when we should be looking forward not 100 years but perhaps 2 to 300 years. Sea level rise is not stopping and schemes such as the Bridgwater Tidal Barrier that just look forward 100 years and stop with no apparent reason defy reason and responsibility; what is the plan afterwards? there isnt one.

Perhaps worst of all for an event sponsored by my own institution, the Institution of Civil Engineers, there were no engineers representing the many companies making money from climate change. Engineer’s created the landscape we have and the current generation should be leading process of planning for our future but seem to have abdicated their interest or responsibility in shaping the land bordering the Severn Estuary.

Somerset and the other counties of England and Wales that border the Severn Estuary need to have a serious conversation and take control of climate change issue at a regional level. The situation needs a champion with authority and knowledge.

21/09/201705/03/2018

Bridgwater Northern Bypass – another opportunity lost

Bridgwater will not be getting a northern bypass anytime soon. Sedgemoor District Council’s HPC strategy to pursue in town traffic improvements in place of a bypass is now widely known. It was delivered in no small part by an option report commissioned by SDC and others Strategic Options Appraisal of Transport Proposals In Bridgwater that came up with a scheme whose cost and schedule ensured that both EDF and SDC could kick the bypass into the long grass.

Following on from the flood of 2014 the Government select committee Environment, Food and Rural Affairs Committee (EFRA) published its report in 2016 Future flood prevention. It proposed that common infrastructure with multiple uses should be built that would maximise value for money; in Bridgwater’s case a bridge with a tidal barrier is value for money. Despite the delay in the start of the Hinkley Point C and the promise of money for the Tidal Surge Barrier no councillor or official considered looking at or revisiting the bypass option.

Logic said put a bridge on the barrier it makes sense.

B300 was a project that started life in 2013 six months before the 2014 floods; it is a commercially viable scheme that includes a proposal to relocate the proposed Bridgwater Tidal Barrier downstream of Dunball and incorporate a road bridge over the River Parrett. The road bridge providing the important first stage of a Northern Bridgwater Bypass and allowing the expansion of Bridgwater to the north of Chilton Trinity.

Bridgwater Tidal Barrier and Road Bridge

Technically there are no major issues with building a barrier downstream of Dunball and in someways its simpler and easier than the proposed site. No need for a diversion channel. The EA did work during its option studies that indicated that if the Bridgwater Tidal Barrier is sited downstream of Dunball the flows in the river system of the River Parrett and King Sedgemoor Drain would be increased ; there was fluvial as well as tidal benefit . Nor is it difficult to put a bridge on the barrier structure. Experience gained on such projects as the Severn Second Crossing brought the costs of the alternative scheme towards the budget for the EA’s proposed site near the Police Station. B300 also proposed to close the gap between the end of the Polden Hills and Wembdon Hill sealing off the South Somerset Level’s from the sea. A proposal with considerable greater integrity than the present novel scheme of an in- town tidal barrier and raised river banks on ground that cannot allow the process of raising them to continue into the future . The B300 scheme would have seen everyone protected and new banks that could be raised in the future unlike the existing scheme that is limited by existing ground conditions.

There was a solution and the additional funding available to deliver a large more comprehensive scheme including tidal flood protection to 1:10,000 return period compared to the 1;200 offered by the EA, a development including low energy homes and industry. The problem is that not all landowners want it. They reason that the ratepayer will ultimately build a bridge to their land and they will not need to make a contribution to the cost, The landowner taking maximum possible value whilst someone else (SDC ratepayers) pay.

Sadly with the EA delivering its Business Plan at the end of the 2017 those few landowners have run the clock down and the opportunity to implement the scheme is fading.

Beyond B300

If a bridge is built sometime in the future as part of a bypass linking the M5’s Junction 23 to Cannington both rate and taxpayer will have paid twice for work in the River Parrett that could have been done once. The aims of the EFRA report on taxpayer value for money will have been completely ignored and the rate and taxpayer left to pick up avoidable costs.

It will also mean that the opportunity will have been lost to protect a larger area of land from the sea and with it the safeguarding of Bridgwater’s future economic expansion to the North West. Bridgwater’s economic expansion and long term flood security sacrificed largely through a sense of entitlement ingrained in many members of the farming community.

Landowners and farmers were recently given assurance on the long term protection of land Chilton Trinity and the Pawlett Hams. People cannot expect to be immune to their decisions; landowners should not expect those that foot the bill (ratepayers) to miss out on better tidal flood protection.

Sedgemoor District Councils’s ratepayers should now carefully consider if supporting landowners at Chilton Trinity is acceptable or whether retaining the EA’s current plan to save money through planned managed realignment of the River Parrett is preferable.

There is good reason that the current managed realignment should be implemented as described in Parrett Estuary Flood Risk Management Strategy. The economic benefit of maintaining the land is small and of no consequence to the majority of SDC ratepayers.

SDC ratepayers should therefore not be expected to provide long term financial support to protect landowners’ assets in Chilton Trinity when a few landowners chose to do nothing and actively block improved flood protection to their land. It is an issue that needs to resolved before the EA and SDC formalise the commitment to farmers in Chilton Trinity on maintaining the river banks and the liability of the maintaining the banks of the River Parrett is added to the tax and ratepayer’s shoulders.

Squandered Opportunities

This is the second time in a decade that Bridgwater has squandered an opportunity to create a bypass, HPC was the first and SDC chose road improvements over a bypass. This time a few landowners are blocking a possible £500M scheme moving forward that would have provided better flood protection for all and possibly a route for EDF.

Public money is being squandered on a single use structure ,Bridgwater Tidal Barrier, as well as the opportunity to secure the future of Bridgwater.

01/07/201711/03/2018

Bridgwater Tidal Barrier Drop in Session 10th July 2017

On the 10^th of July at Bridgwater Town Hall (2-7pm) the EA and SDC will reveal the final form of their scheme for the Bridgwater Tidal Barrier. Its construction will shape the town for the next two hundred years. It is planned to be commissioned in 2024 and designed to operate for 100 years. The operational date is a political one rather than climate driven and unlike most similar structures it will be located within the town rather than at the mouth of the river. Mitigation of a similar fluvial flood event to 2014 is not part of the barrier’s function.

People have been focused on the barrier yet the river banks are the important bit; what happens to them will decide how radically our existing landscape will change and have far greater impact than a set of gates. The downstream river banks are being maintained in accordance with the FCERM Strategy (the national flood and coastal erosion risk management strategy for England).Individual polices are detailed in the local 2010 Shoreline Management Plan covering the next 20, 50 and 100 years.

For the Parrett those policies say that within the operational life of the barrier “The long term vision is for a more naturally functioning estuary, through construction of set-back defences under a policy of managed realignment.” Land is being returned to the tidal zone.

EA maps produced in 2010 show how that will be achieved at Pawlett Hams and Chilton Trinity. The recently released BTB secondary flood defence plan and residual flood risk maps show the long term policies are being put in place. Only the river banks close to Combwich and Chilton Trinity housing will continue to be raised. Farmland will ultimately be flooded and lost as the majority of the river banks will cease to be raised to match climate change. Steart Peninsula’s habitat will in due course be extended to Dunball and Chilton Trinity.

The present scheme means that the opportunity to increase the conveyance capacity of the Parrett capacity by moving a future replacement barrier downstream is lost. Taunton Deane and South Somerset may have to build fluvial storage on their land in the future. Opportunities for a cost effective bypass will be lost to the detriment of Bridgwater and West Somerset. As a naturally occurring event Somerset land owners will not receive compensation. Bridgwater will pay around £20m in lost land values towards the present scheme. A major economic impact on Somerset as a whole is just being ignored.

It is simply not true or credible that the BTB can somehow be divorced from the EA’s longer plan for the Parrett Estuary; a plan prepared in 2010 predating the 2014 flooding of the Somerset Levels.

The Bridgwater Tidal barrier in its present form passed its sell by date in 2014 when fluvial flooding moved from management on the Levels to flooding within our homes. Even today people still imagine that the Bridgwater Tidal Barrier is somehow part of the scheme to mitigate the 2014 flood, it could be but it isn’t. The Levels’ will still flood as they did in 2014 if we get similar weather conditions.

With little information in the public domain including the option studies that supported the original 7 location and the shorter list of 4 it is not unreasonable that this scheme has many questions of transparency. it is unacceptable that important and relevant information is not available to the public ahead of the final consultation on the 10^th of July. That flood maps produced in September 2016 have only just been published giving people little time to understand the implications of what is planned.

If the FCERM Strategy and Parrett Estuary Flood Management Strategy are executed in their present form 1000’s of acres of agricultural land will be lost to food production. Is it morally right that the UK which cannot feed itself should export even more of its food production overseas and possibly deny food to others? This lack of responsibility on our part will no doubt be further compounded when our overseas aid budget has to be used to relieve a famine we as a nation knowingly or perhaps worse unknowingly contributed to.

To reach this situation there is a clear lack of leadership, vision, scrutiny and oversight by those organisations and people charged with delivering the plan and the infrastructure for Somerset. Neither SDC nor the SRA has any engineering or qualified staff able to lead on flooding and has chosen not to bring in people that could. There is also a clear engineering deficit in the delivery of Somerset’s flood defences.

People should go along to the consultation and ask

Is turning the River Parrett back 500 to 1000 years and extending the Steart Peninsula wildlife habitat to Dunball whilst constraining economic development really what Bridgwater and wider Somerset need?
Why wasn’t a barrier considered at Combwich and extending to Pawlett Hill that would protect the whole area. Arguments that we might impinge on the edge of the SSI is not an argument for not even looking at the possibility.
Why does the barrier only do TIDAL and not FLUVIAL (2014 rainfall) with equal importance?
What is the extra cost of building a barrier with a bridge on it?

Steve Trowbridge CEng MICE MIStructE

23/06/2017

Bridgwater Tidal Barrier is not in such a stupid place.

Bridgwater will shortly be given its final opportunity to be consulted on the planned Bridgwater Tidal Barrier at its chosen location near Express Park. Did anyone really wonder why Bridgwater’s barrier, probably uniquely in the UK, is situated not at or close to the mouth of the River Parrett?

The reason is that in 100 years or so time it probably will be.

The start of the River Parrett will have moved to be at or just upstream of Dunball where the secondary flood defences meet the raised raised river bank.

The EA’s well concealed Shoreline Management Plan (SMP) intends over the next 100 years to return the Parrett Estuary to its original form. They intend to allow the sea to over-top the river banks spilling out over the existing farm land to ultimately form an inter tidal habitat stretching from the Steart to Dunball.

People have been told by EA that “river banks will be maintained” and imagine the EA intends to continue raising the river banks. That is not true; what it actually means is that the banks will stay at the preset level whilst sea levels continue to rise. Ultimately the sea will come over the top of the banks naturally generating the planned realignment of the Parrett and avoiding paying landowners compensation. Banks will only be raised locally and the impact can be seen on the recently released flood maps. This was known about before the September 2016 consultation but never presented. The EA’s repeated statement on protection is duplicitous at best and misleading at worse.

To compound the EA’s lack of transparency it seems to have lost its moral compass with regard to those less fortunate. Locally with nearly 2000 acres at Steart already lost to food production the EA’s SMP will see another 3000 acres lost to UK food production at time of growing food insecurity . As a country that cannot feed its self that lost acreage along with all the rest of land lost through Managed Realignment will have to be replaced overseas taking away food that could be used for famine relief and the less well off. It is the worst type of modern colonialism. It is a situation made all the worse by the fact that the UK’s aid fund may be trying to alleviate problems we are causing. Not much in the way of joined up government.

Serious questions need to be asked of the those County and District Councillors who seem to be on all the committees but do little to bring the EA to account and are prepared to promote the exploitation of other people’s land to avoid looking after our own.

05/06/201726/09/2018

Chilton Trinity and Pawlett Hams

The EA’s 2011 document Managing flood risk on the Severn Estuary provided the EA’s vision for Steart Peninsula including what subsequently became the Steart Marshes salt marsh scheme.

Pawlett Hams no longer protected after 2030

Under present plans six years after the completion of the proposed Bridgwater Tidal Barrier Pawlett Hams will cease to be defended. That means that the river banks will no longer be maintained and the process of handing more farmland back to the sea will start again. The estuary will in time return to the state it was in more than 500 years ago before the levels were drained. According to the EA this will see 387 Ha or just under 1000 acres of farmland lost to food production and the local economy although only 47Ha is actually required to make up for coastline squeeze.

The Parrett Estuary Flood Risk Management Strategy (PEFRMS) is a document remarkable for its narrow vision that is more interested in extending the habitat for birds whilst completely failing to understand or chooses to stay silent on the impact of saltwater on agricultural land. The only economic impact considered seems to be tourism.

Parrett Flood Management Recommended Strategy

Section 2.1.6 (b) notes that

North Devon and Somerset Shoreline Management Plan (Hartland Point to Anchor Head), Halcrow, due 2010. We are concurring with their emerging policies.

As such much of the real detail is provided in the EA’s Shoreline Management Plan rather than the overarching Parrett Estuary Flood Management Strategy which is a long term plan to let down the flood defences along the River Parrett allowing the sea up to the edge of Chilton Trinity and trading off land in Sedgemoor for economic development elsewhere around the Severn Estuary. It is a step back in time with individual communities afforded long term term flood protection rather than comprehensive flood defence. The high level strategy for the PEFRMS is provided below following on is information from the shoreline management plan and recently available information for the preferential flooding of farmland as part of the Bridgwater Tidal Barrier Scheme.

Pawlett Hams Realignment is the complete loss of Pawlett Hams as can be seen from the key plan in the Parrett Estuary Flood Management Strategy and noted in item c above.

Applicable Shoreline Management Plan delivery of the Strategy that includes the loss of 387 Hectares (1000 Acres of land) at Pawlett Hams is reproduced below.

Parrett Estuary (Combwich to River Brue) Policies 7d38 to 7d42

Individual policies for various sections of the River Parrett and adjacent land are listed below. 7d39 is worth noting as it has the next major realignment of the flood defences after Pawlett Hams allowing the River Parrett to come up within 1000m of the village of Chilton Trinity.

Full copies of the EA policies can be found at

Steart Peninsula (Stolford to Combwich) 7d34 to 7d37

Parrett Estuary (Combwich to River Brue) 7d38 to 7d42

Timescales

all documents refer to timescales and these are

Short Term (to 2025)
Medium Term (to 2055)
Long Term (to 2105)

Chilton Trinity

South of the Parrett the EA ultimately proposed to let the marshes return to the very edge of Bridgwater whilst Sedgemoor District Council and the EA’s Bridgwater Barrier team have left a space at site 4 for a bridge that is on the way to a planned inter tidal area and represents the expansion of the Steart Peninsula scheme up to Bridgwater.

EA presentation Severn Estuary Forum 2017

Managed Realignment

the planned retreat of the existing flood defences

Policy 7d42 Flood defences from Dunball To the River Brue

Policy 7d39 Combwich to Bridgwater (Parrett west) managed realignment.

Those two policies when implemented will along with Steart Marshes and the Bristol Ports land transform the Parrett Estuary. There will be no new link possible between West and East Somerset.

Future (long term) Inter tidal habitat – salt marsh and mud flats

Total agricultural land lost to agricultural will be around 5000 acres. There is a certain irony that the EA policies will in reducing UK agricultural land export food production abroad and potentially increase famine oversees.

In the short term the proposed secondary flood defences shown below are required because the EA will not keep raising the banks above the present levels. sea level rise will continue and the frequency of seawater flooding will increase. The route of the secondary flood defence is not dissimilar to the future managed realignment above.

Secondary Flood Banks based on Bridgwater Tidal Barrier at Site 5

The gap in the flood defences at Walpole still left open for floodwater to flood the area as it previously did in the 80’s

After the planned completion of the Bridgwater Tidal Barrier a 1:200 flood is expected by the designers to flood land to the north of Chilton Trinity with saltwater. The maps below represent some of the 50 maps prepared by the BTB designers to support the decision on location of the BTB barrier; the complete set of maps can be found on the SDC Strategic Flood Risk Assessment page.

The maps below show the impact of the river banks not being raised to match rising sea levels apart from the protected communities. The end result is the preferential flooding of farmland with saltwater during certain tide and storm conditions as presented during the Severn Estuary Forum 2017 held in Bridgwater.

None of this information was presented during the two EA/SDC public consultations in 2016.

The map below shows one of breach locations modelled. A breach can occur anywhere, the map does not say its saline (salt) flood waters escaping from the river. They are merely designed to provide an idea of the likely consequence of it happening. The full pack of maps shows a number of breach locations and these are yet to published by Sedgemoor District Council.

River Bank fails at Dunball at land to the north of Chilton Trinity flooded

One of the maps produced by the designer showing the safety risks associated with their present scheme.

BRIDGWATER TIDAL BARRIER ; SITE 5; FLOOD HAZARD 1 :1000 YEAR FLOOD EVENT

26/05/201709/06/2017

Somerset Flooding- A silver lining lost

A year or so ago when Sedgemoor District Council (SDC) and the Environment Agency started work on the Bridgwater Tidal Barrier (BTB) scheme they jointly decided not to spend money on an economic impact assessment.

As a result of that decision there is now no way for councillors, ratepayers and business to measure and benchmark the wider commercial and economic impacts of BTB project. The project is now simply valued and measured by government rules. This is especially important for those ratepayers and the HoW LEP who will directly pay for a proportion of this scheme. For Somerset’s councillors there is no visibility of the potential direct local (Somerset wide) benefit. With a preferred location agreed and the full details still yet to be seen or shown to the public it is difficult to see how the Bridgwater Tidal Barrier can be proceeding as it is.

There is a need to scrutinise the EA’s proposed Bridgwater Tidal Barrier and its management of the delivery of the scheme. There urgently needs to be some form of independent peer review to support the decisions of councillors and EA employees who do not have suitable engineering qualifications and experience. No private company would do this.

The River Parrett catchment and its capacity affects much of South and Central Somerset; almost every town is on one of its tributaries. The wider opportunity that Somerset’s flood defence expenditure presents has to date been largely ignored and is in danger of being squandered. Sensible promises made in 2014 have been quietly allowed to disappear.

If you live within the Parrett Catchment or in West Somerset this article will be worth reading for economic reasons alone.

By 2024 nearly £100M will have been spent on flood related work within Somerset and the majority of the money focused to the north and north west of Bridgwater. The EA’s managed realignment at Steart Peninsula and the adjacent Bristol Ports property deal for it proposed container port that is of no economic benefit to Somerset sees nearly 3000 acres of farmland removed from the the local economy.

However

The Levels will still flood and as they did in 2014; they will simply drain more quickly.
A flood defence system will have been built that only works for sea water (tidal) and that will probably have to be replaced because it will not be viable to extend its design life because of the ground conditions along the river banks.
The expansion of Bridgwater over the next 100 years ignored.
The rather novel concept of putting a tidal flood barrier 5 miles upstream of the mouth of the River Parrett and into the town implemented.
An additional 2,000 acres of productive agricultural land will be in the process of being lost to agricultural bringing the total of land lost to the local economy to 5,000 acres including Steart Peninsular and the Bristol Ports land deal.
There will be no bridge over the Parrett although the myth that you cannot easily have both on one structure will have been discredited albeit too late.
No beneficial integration with a future Bridgwater bypass considered or provided.
An important relationships between the capacity of the KSD/Sowy expansion and the impact of the location of the BTB never mentioned or costed.
The planned loss of Pawlett Hams to the sea lying hidden in the Parrett Estuary Flood Risk Management Strategy.

Perhaps the most unfortunate decision to date was naming the barrier/barrage the Bridgwater Tidal Barrier and sending mixed messages as to its purpose. That single act has reduced interest and scrutiny both in Sedgemoor and further afield to almost nothing. Only 180 people came to a public consultation in September 2016.

The introduction on the SDC barrier website reproduced below implies on the last line that it “could play a critical role in reducing flood risk” (tidal) and not the fluvial flow it started talking abut; they are not the same thing but did meet once in 2014. Two different things have been conflated into one message.

The barrier is not designed to mitigate a another 2014 flood

with regard to fluvial (rainfall) flooding

Would it now have had an impact on another 2014 flood? NO
Could it be made to have an impact on another 2014 Flood YES.

Somerset’s councils seem to have no interest in this scheme yet they should because

Somerset County Council (SCC)

Despite having the SRA under its wing and councillors jointly at County and District level there is little in the way of a long term vision that can be see being developed.

A shorter more strategic tidal scheme closing off the South Somerset Levels from the sea by closing the short gap between the hills from Combwich to Pawlett Hill has not been considered.

Such a scheme would

Secure the south Somerset Levels from the sea.
Improve the fluvial capacity of the River Parrett to the benefit of Taunton Deane and South Somerset as well as Sedgemoor.
Provide a bypass and improved road link to West Somerset using EDF’s extended Cannington Bypass.

West Somerset

West Somerset’s economic development is constrained by two roads (A39 & A358) and the need to navigate across either Bridgwater (A39) and Taunton (A358) road systems to get to the M5. With little or no options and no Government money available as part of its road budget it is an area of Somerset where the wealth and opportunity of its population is always constrained and likely to continue. No doubt why it loses industry and income.

It is difficult to understand why West Somerset isn’t trying to improve its economic link to the M5 motorway and via the A39 to Frome, Wells, Shepton Mallet, Street, Glastonbury and Yeovil.

Constructing the Bridgwater Tidal Barrier at Combwich with a road bridge taking advantage of the recently constructed EDF extension to the Cannington Bypass would provide a significant economic benefit to West Somerset.

Taunton Deane & South Somerset

Both local authorities rely on their respective tributaries Rivers Isle, Cary and Tone to convey surface water to the River Parrett and onwards to the sea. No amount of SUDs, storage on the Levels or slow the flow is going to change the fact that you can only get so much fluvial flood water out through the River Parrett. That constraint will ultimately have to be faced by limiting economic development The opportunity has not been taken to leverage the long term benefits for the two districts by moving the barrier downstream.

The reason to relocate the selected Bridgwater Tidal Barrier site downstream is that its preferred location does almost nothing to improve the conveyance of surface water to the sea. Where it is now proposed above the King Sedgemoor Drain outfall means that the full benefit of the KSD/Sowy expansion cannot be achieved or the capacity of the River Parrett optimised. Capacity that would benefit largely Taunton Deane and South Somerset. That scheme is being paid for by everyone and is simply not as good value for money as it could be. Rising sea and tide levels will reduce the time the KSD sluices can discharge. That situation will invariably negatively impact both districts by limiting how much water can go in to the system at their end.

It is therefore surprising that neither council has been pushing the barrier downstream where it could be used to increase conveyance in the same way as the Thames Barrier does. Increasing the overall capacity of the system when the Levels again flood is the priority and an opportunity not to missed offers one less obstruction to those two districts economic development.

Sedgemoor District Council (SDC)

South Somerset Levels

Sedgemoor opted to support a 15Km long scheme that cannot be extended (raised) as sea levels rise. Somewhere a bigger one will be required. Its consultants never looked at what would be the best scheme for Somerset or indeed wider Bridgwater. It is just what would be the cheapest for the EA whilst the SRA and SDC looked on. A location for the barrier where a bridge cannot be added to it is hardly planning for the future but it does ensure the ratepayer does not get value for money.

North Somerset Levels

Defending the North Somerset Levels could be achieved by the construction a new barrier from the Polden Hills to end of the Mendips (Brean Down). Such an undertaking could be easily done providing undeveloped land is identified. We could create a second line of defence over the next 30 years letting Somerset contractors run recycling operations allowing trains to bring in recycled materials to form a continuous flood defence. Its time managed retreat was abandoned.

What is disappointing is that with the SDC Local Plan under development there is no land being reserved for future improvements to the flood defences. The organised surrender of Somerset’s hard won land is being orchestrated by the EA under its Managed Realignment process and no one is challenging it. Everyone in Somerset should be interested in what is being done along the coast for safety and economic reasons. There is simply no plan.

Heart of the South West LEP

The Heart of the West LEP with its support of the BTB a project will ultimately damage local businesses based in most districts (£16-20M of lost land values) whilst in a current study is looking at improving rural businesses . The LEP is an organisation facing both ways to the detriment of everyone.

Somerset needs some joined up thinking and understand the very negative implications of some of Somerset’s flood defence scheme.Only when its built and its limits apparent will people say “if only”.

The Options looked at by the EA lacked any sort of imagination or offered a long term solution; were simply variations on a theme and ignored the nearby topography that offered other options for the Bridgwater Tidal Barrier

It is unacceptable that better engineering options were not identified and presented to councillors; ultimately it should be the ratepayers decision to go for a better solution if they want to. The EA should not presume as it has in this case.

On the 14th July starting at 10.00 am the first opportunity to do something takes place when the SRA scrutiny committee meets in open session at Somerset County Hall, TA1 4DY.

Some Questions to Ask

Why is the Bridgwater Tidal Barrier not also designed to help to mitigate the effects of a similar flood to 2014?
What is the replacement plan for the Bridgwater Tidal Barrier?
What is the cost of a scheme with a bridge ?
Should we only be spending our money on such a limited scheme?
Why wasn’t Combwich and the resulting shorter flood defence system that protects a larger area than the current scheme considered by the EA?
Does the extension of the Cannington bypass towards Combwich necessitate the reassessment of the present scheme?
Should Somerset County Council be looking at a more holistic scheme for Somerset?
Should SCC commission a county wide economic assessment of what an alternative barrier scheme might deliver?
Do we need the EA or should the SRA be expanded to become a delivery focused organisation and the EA limited to a statutory consultee ?
Is the role of environmental charities in developing and influencing flood policy beneficial and do they have a conflict of interest?
Why after 3 years since the flood and 8 years since the barrier identified as the preferred solution is there almost no information about the scheme on the http://www.sedgemoor.gov.uk/bridgwaterbarrier website?

The EA plan another consultation on the full scheme later in 2017. Councillors of all Somerset’s districts might like to look at the economic impact of this scheme (BTB) on their own areas and perhaps county might look at the bigger picture.

An unintended consequence is only the failure to adequately consider a decision before it was made.

25/05/201727/08/2018

The River Parrett – how it works

Rivers that discharge into the Severn Estuary are very different from most UK rivers. With a tidal range in the estuary of around 11m MLWN -3. 0 and MLWS -5.7 AOD and the river bed level at around 0.00 AOD. These levels means that at low tide in the estuary the water level is always below the bed of the River Parrett and the river simply empties into the estuary. In the case of the Parrett its a process that goes as far upstream as Oath and the changing tide sees the river refilling from the sea.

What is seen looking over the Bridgwater’s bridges is just one half of the normal tidal cycle you would see at the coast; at low (ebb) tide its purely fresh water going out and that can be seen on the West Quay tidal gauge where the graph flattens. Equally the point at where incoming seawater (saltwater) takes over from the freshwater of the Parrett and becomes a relatively small component of the rivers water can also estimated.

At low tides the river empties so completely that during periods of low fluvial flow it can actually dry out so much so that upstream of Combwich there is an old iron age path where people simply walked across the river at low tide.

High tides can be nearly 2m above the surrounding land and at Bristol Road nearly as high as the head of the doors and over the next hundred years that will continue to grow .

Ecologically it is largely a dead river. Nature likes, however bad, a consistent environment and the Parrett offers the greatest of changes twice a day from empty to full and freshwater to saltwater. The large amounts of Seven Estuary silt that arrives with the tides exclude sunlight and there is nothing to generate oxygen. Fish(salmon) and Elvers just transit the river on their way to the fresh water of the River Parrett and its tributaries.

It is a true challenge for The EU Water Framework Directive as there is little negative actions that can be done to it. The lack of water does not deter unrealistic claims that fisheries exist in the river.

The images below show River Parrett tides ( courtesy of GaugeMap)

The Hinkley Point tide gauge above shows the full cycle of the tide in compoarison to the truncated cycle at West Quay which is caused by the river bed being higher than the sea bed in the Seven Estuary.

Looking along the river it could be shown

2014 Flood

In 2014 the Somerset Levels flooded, normally excess water is stored on the levels and then pumped back into the river when the weather improves and fluvial flows have reduced. The floods occurred because the flood storage capacity of the land was exceeded.

The response to the flood and still the current plan is pumps some more fixed ones and temporary platforms for hired pumps such as the permanent platform at Dunball made ready for the next time the levels flood and improvements made to how fast the flood water can be drained off the Levels.

One important question is whether its possible to increase the amount of water that flows down the river without pumps?

The answer is yes; the Thames Barrier is used in that way when there is flooding and the Thames and its tributaries are at capacity. The barrier gates are closed at low tide creating a shallow reservoir normally filled by the incoming tide and floodwater coming down the river fills it up. Previous references to the Thames Barrier and the River Parrett were in relation to the type of gate rather than how the system operates.

How might it work in the River Parrett?

There are two sources of fluvial floes into the Parrett. The Parrett and King SedgemoorDrain (KSD) /Sowy River. Water unable to get down the River Parrett is diverted around Bridgwater via the KSD/Sowy and re-enters the Parrett at Dunball.

Both sources can discharge when the tide is out but become tide locked when the sea re-enters the river. Creating a large temporary empty length of river downstream of Dunball would allow both sources to continue flowing and when full and matched with the tide allowed to go to the sea.

To do this a gate is needed downstream of Dunball and the best location would be Combwich or somewhere in between. The Bridgwater Tidal Barrier is a gate that could have been used to do this.

EA Downstream Scheme

The current plan is to build the Bridgwater Tidal Barrier upstream of Dunball Clyce and with sea and tide levels continuing to rise allowing the sea to reclaim the farmland at Chilton Trinity and Pawlett Hams. The existing system returning to an inter tidal saltmarsh/mudflat covering the existing farmland at Pawlett Hams and most of the land to the north of the village of Chilton Trinity. The drawing below shows how the regime will change over the years to come.