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.

Areas of Potential Saltmarsh

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.

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.

Peruvian Duckweed

Most of us, especially if you live on the Somerset Levels or the Norfolk Broads, often see our rhynes (ditches) and ponds covered in duckweed.

It is not the pest we think it is.

This week after nearly  two years preparatory work and 40 years of passion by Texas based  inventor of the system Paul Skilicorn. I am in Peru as part of Lyndon Water‘s management  team led by CEO  Ray Anderson working to deliver a truly unique water treatment project. Using duckweed as a key element in the treatment process we will  clean  urban  wastewater on an industrial scale and then turn it into potable drinking water to WHO standards. Water to the same standard that in Europe we take for granted 24 hours a day.

If all goes to plan in a little under 18 months people in an area of northern Peru will be free of a 30 year stench from its failed sewage treatment plant  and the region receiving additional potable water to increase availability of drinking water and reduce the strain on depleting aquifers.

October 2018 Update

Paul Skillicorn  recently left Lyndon Water and has set up a  competing business. with Ramiro Priale. 

Why Duckweed?

Duckweed is just about the fastest growing plant in the world. As duckweed grows it removes nutrients and  other contaminants converting suspended elements in wastewater  into usable biomass. We  separate and take the suspended solids for anaerobic digestion to generate power before the duckweed cleans the water. 

Duckweed under the Lyndon Water process is harvested and converted into fish food, animal feed, high protein superfoods or for energy generation. Some of the feed we produce will then be used to support Lyndon Water‘ s food  production at a new and nearby integral fish farm and Aquaponics facility that forms part of the Lyndon Water system. Nothing is wasted.

Glue 2’s  Duckweed Harvester and lagoon system.
Glue2’s vision of what future water treatment might look like this.

The harvester design  and the lagoon system design is by my  engineering consultancy  Glue2 Limited . We have also developed  a process for  concurrent transportation and processing of duckweed suitable for use in remote locations using minimal permanent infrastructure. All equipment and buildings are modularised and  based on ISO containers and dimensions.

We take wastewater and make drinking water, the waste we turn into food and power. What’s not to like?

When you  next see  duckweed covering a pond  or rhyne it’s not a pest but it’s cleaning up our water. It’s not all of the story of the process but it is the key.

Lyndon Water led by Ray Anderson off to see the Peruvian Government in Lima

Director Paul Bryant, CEO Ray Anderson, Lyndon Water in Country Manager Ramiro Priale & Chairman Lewis Jeffery

Letter of community support for our project just received 15th August 2017

Retention of Concrete Consistency

Designing concrete mixes for specific purposes often raises questions that you don’t know the answers to. Familiar products have fallen into disuse and new products are just new. A recent project in Shetland required a mix able to get into areas of heavily congested reinforcement that had previously failed the first time around.

Highly plasticised mixes look and behave differently from “ normal “ concrete and  the current mix was  a 100% Portland cement mix that  appeared to have followed me over from Abu Dhabi with the same original contractor having developed a similar mix for two different projects. Shetland and Abu Dhabi having in common a lack of cement replacements particularly in the oil & gas industry. A situation further complicated  as  the current mix had a very high cement content was plasticised but not retarded making it very difficult to use in all but the simplest pours. It has  very little time to be placed.

The rework had a number of challenges that followed from the earlier pour.

  • Hanging shutters that obstructed the passage of concrete.
  • A relatively small volume; less than 10m3
  • Over detailing of reinforcement; surplus reinforcement that had not been removed during original  fixing.
  • Complicated shuttering and finishing that required considerable time to complete after the bulk of the concrete had been placed.

For the revised rework mix a new mix  with the following requirements was developed.

  1. A 10mm aggregate for  congestion and cover issues.
  2. Place using the chute from the back of the truck.
  3. Delay the setting time to around 3 hours.
  4. Retain the waterproof qualities of the existing mix.
  5. Characteristic strength of 35N
  6. Satisfy durability requirements for a Marine Environment.

TESTING & APPROVAL

Sika provided an S4 mix design based on the above requirement;  to obtain client approval and to understand what we had and how it worked a simple test was done twice.

Batches of the revised concrete  mix were mixed and held in a truck mixer replicating a long discharge time on site.

The truck mixer was progressively emptied over 3 hours.

Slump test were taken every 20 minutes and cubes at hourly intervals (1,2 and 3 hours) for testing at 7 and 28 days.

Testing at EMN Plant’s Scatska Batching Plant in Shetland April 2017

RESULTS

they were very good

  • the mix stayed at or round the design slump only marginally dropping off in the last two results  but still within limits.
  • cube results were consistent and all passed.

LESSON LEARNT

One important thing that was noted was that the consistency (slump) potentially drops for a short period below the specification ,about 1 hour after batching was completed, and then regains the required consistency. It occurred on both batches.

The lesson for Contractors, Consultants  and QA /QC processes is that

  • The time from batching to the initial test is important and that there is the potential to reject concrete that is actually ok.
  • When doing trial mixes develop tests that explore  what could happen when a concrete pour goes wrong and placing of concrete is delayed identifying any characteristics that might explain a rogue test result during placing operations.

 

 

Bridgwater Tidal Barrier Drop in Session 10th July 2017

On the 10th 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 10th 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

  1. 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?
  2. 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.
  3. Why does the barrier only do TIDAL and not  FLUVIAL (2014 rainfall) with equal importance?
  4. What is the extra cost of building a barrier with a bridge on it?

 

Steve Trowbridge CEng MICE MIStructE

 

 

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.

 

 

 

 

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.

Policies 7d38 to 7d42

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. 

2025 1:200 Flood Return

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

 

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.

River Parrett Catchment Area

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.

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)

West Quay One days Tides
West Quay One weeks Tides
HPC Tide Gauge

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.

West Quay- One Months Tides

Looking along the river it could be shown

River Parrett at Low Tide

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.

Dunball Clyce (River Parrett side)

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.

River Parrett – Increasing the Flow

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.

River Parrett at Chilton Trinity & Pawlett Hams showing planned next 100 years

The information can be found in

The Parrett Estuary Flood Flood Risk Management Strategy

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

further information with flood maps can be found in the article on

Chilton Trinity and Pawlett Hams

 

 

 

 

Somerset’s 20 Year Flood Action Plan is not a Plan

Has anyone noticed  there actually isn’t really a plan for managing flooding in Somerset  be it Tidal or Fluvial. Lots of headlines and pictures of grandstanding councillors on river banks  but little substance.  Our particular collective flood Emperor has no clothes whilst the myth that somehow the Bridgwater Tidal Barrier (BTB) is part of the solution to the avoiding a repeat of the 2014 flood is allowed to persist. People imagine that things are being done and there is a big picture somewhere. There isnt.

The Somerset 20 Year Flood Action Plan is little more than a  maintenance list that should have been done and wasn’t; it is a complete misnomer. In three years since the 2014 flood  there is no  big plan looking forward  the next 200 years. There is no context that  explains where the value of all the money being spent is.

There is no excuse for such short sighted behaviour by our officials and elected representatives. At least the Somerset Rivers Authority (SRA) carried out an economic impact assessment of the 2014 flood which is more than the EA and Sedgemoor District Council (SDC) have done for the Bridgwater Tidal  Barrier.

The development of new ideas  seems to be more akin to those seeking alternative medicinal remedies; they seem to be ones that will turn the Levels into some theme park rather than look at something that can be delivered over the decades and centuries ahead. The  Managed  Retreat (Realignment) of our coastline is not a panacea to rising sea levels; it has its place but  needs to be challenged when there are viable options.  Giving the EA the excuse and licence to do little or nothing is not acceptable. Those involved with W&WT and the RSPB as consistent beneficiaries of these  EA policies and alongside Natural England makes an unholy alliance  that is no friend of Somerset’s people.

Plenty of councillors are sat on committees and they should be ensuring rigorous debate and the publishing of useful information rather than the almost complete lack of detail in the public domain. The private sector would not be allowed to get away with this lack of transparency or vision.

Since 2014 when it was rushed together for political expediency  little has been done or achieved whilst show case projects are not what they seem

Bridgwater Tidal Barrier

Despite knowing that  the rise in sea level  has no recognised end date Somerset has decided on a  100 year scheme. Our King Canute moment.

We are going to build a scheme that cannot be easily extended or modified knowing full well that something else will be needed in the future but we haven’t decided what. A scheme that  unlike any conventional tidal surge barrier  it is  actually to be in the town rather than down stream and at the mouth of the river. Bridgwater in  probably 10 rather than 100 years will have enveloped the proposed barrier site.  A solution with built in obsolescence that  can be bypassed on day one does not seem a great idea. Children born today may see the BTB torn down. Why would Bridgwater  buy it?”

Options such as closing the gap between Stockland Bristol  and Pawlett Hill less than 2 Km  ( 1.3 miles) long compared to around 15 km (10 miles) both banks from Combwich to the selected site in Bridgwater or 7.5 Km  if you allow Pawlett Hams to go the way of Steart Peninsula.

Two option studies paid for by the taxpayer and Combwich  not even considered as an option in either and the  backdoor flood route at Walpole still not acknowledged when the EA visits landowners. The credibility of the EA , its consultants and our oversight committees is very poor.

King Sedgemoor Drain Improvement

The King Sedgemoor Drain improvement is a Fluvial conveyance scheme that cannot reach its full potential because of the location of the tidal BTB upstream of Dunball Clyce. The EA in this matter described themselves in recent correspondence as the SRA’s sub contractor.

Silos

Flood schemes are kept in silos of fluvial and tidal rather than in developing a single holistic solution for Somerset. The EA and other organisations make it very difficult  to see the full picture. There is a serious lack of transparency,  accountability and independent review in the process.

By 2024 nearly £100m will have been spent and the Levels will still flood. The Bridgwater Tidal Barrier is seen and portrayed as a Bridgwater only scheme where as moving it downstream  of the KSD outfall would increase conveyance  under fluvial conditions benefiting the districts of Taunton Deane and South Somerset. The SRA is nowhere to be seen generating debate and  bringing together people to achieve a wider benefit to Somerset with state and local ratepayers money which was its reason to be created. The SRA’s one big opportunity missed. This is notwithstanding the missed economic opportunity for West Somerset

Transparency

There is more information in the public domain about EDF’s Hinkley Point C power station then there is about these schemes especially the Bridgwater Tidal Barrier. It appears  the EA did not want the Chilton Trinity  and Pawlett Hams landowners to be aware of  what would not be done to protect their land choosing to hide behind the rather opaque Parrett Estuary Flood Risk Management Strategy. Something noticeably low key to the point of invisibility  in the EA’s 2016 consultations at the Bridgwater Art’s Centre.

The reasons  that undertakings given by the EA and SDC in Protecting Bridgwater and the Somerset Levels & Moors from Tidal Flooding-Flood Risk Management Review -November 2014 were never followed through and just quietly dropped has never been explained.

No imagination  and no vision for our children’s future

With a blank sheet of paper and little or no restrictions on what we might do to protect the South Somerset Levels including areas of Sedgemoor, Taunton Deane and  South Somerset there is still a blank piece of paper. Rarely has such an opportunity been squandered.

There is nothing that explains what happens to the Tidal Surge Barrier when we cannot raise the banks any longer which in reality we cant now and Pawlett Hams and Chilton Trinity have become mudflats/ salt marsh  and the cost of building downstream  prohibitive.

What we do have is lots of committees

Wessex Regional Flood and Coastal Committee (RFCC)

Board of the Somerset Rivers Authority (SRA)

SRA Joint Scrutiny Panel

Somerset Drainage Board Consortium (IDB)

Its interesting to note how many people sit  on more than one of these committees. These committees  have people with no engineering knowledge or experience apart from the EA & IDB and all EA’s donkey work is done by US and Canadian third party consultants with no attachment to the area. The EA’s contribution to Somerset is questionable now as they have been reduced to little more than a middle man.

we must also not forget the groups

  • SRA  Management Group
  • SRA Technical Group
  • Bristol Channel Strategic Coastal Group
  • South West Coastal Group
  • Southern Coastal Group

It really is time that Somerset had  a suitable organisation capable of bringing a long term vision to secure the future of Somerset. Whilst attendance at committees is so lucrative  nothing is going to get done .  The EA is not a delivery based organisation and needs to be changed or replaced.  The SRA has no structure or suitable people able to develop and execute the vision and solution we need. The system  we have is clearly not fit for purpose.

The situation for Somerset, the rest of the West Country and no doubt other regions of the UK is that they need their own independent Engineers with local knowledge. Engineers able  to provide continuity  in advice to the committees and oversee the EA and IDB and other agencies.

We cannot afford

  • that each agency (EA, Highways, Rail) continues to builds its own thing, we need to combine flood defence with other infrastructure works.
  • that strategic flood decisions can be left to seconded senior local authority officers  with little or no knowledge of the subject.
  • the lack of an independent peer review process.
  • The lack of transparency – there is nothing published on the BTB website that tells you why.  There is little value value in an undated progress report  that can be found there  that does not measure progress. 
  • all these organisations whose main purpose seems to be to invite people from other groups to attend their meetings at our expense.

WE NEED A PLAN and we need to end the Flooding Golden Goose. 

on the 14th of July 2017  a meeting of the Scrutiny Committee  will take place in Taunton . It is open to the public. 

http://www.somersetriversauthority.org.uk/about-us/sra-scrutiny-meetings-and-papers/