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Sustainable Flood Defence

The UK has a serious problem with leadership and sustainable construction where flood defence is concerned. There is a profound lack of critical thinking in the delivery of future UK flood defences and an unwillingness by agencies to get their  hands dirty at a local level. As a consequence government continues to fail regarding sustainability and value for money; taxpayer funded agencies seem unable or unwilling to work together.  It is a situation compounded by wildlife and environmental organisations who have seen an opportunity to gain control of and modify land in much the same way that monasteries such as Glastonbury once did.

Flood defence schemes are invariably seen in terms of a definable project that can be closed rather than the first step of a sustainable long term solution. The protected community needs to live with and manage these schemes  for 100’s of years after they are built. Our thinking on delivery is just too short and too expensive when it is a 300 year or so problem and especially when the initial solution only has a 100 year design life; it makes little sense. There is an obvious gap. That gap  means that today’s options should at least consider what happens next. Should we really  be adopting a solution today requiring the construction of a  replacement barrier tomorrow rather than a scheme today that has  provision or a plan for extending it already built in? Our current scheme takes planned obsolescence to a new level.

We should not be closing out future options for the generations that follow and we should follow our own rules for sustainable development

“Sustainable development is development that meets the needs of the present, without compromising the ability of future generations to meet their own needs.”

Delivery of the Bridgwater Tidal Barrier continues to be an exemplar of non-sustainable thinking. Part of the scheme requires the river banks between the tidal barrier and the village of Combwich to be maintained. The EA’s plan to do this work as part of the barrier construction contract. Material is to be dug from the adjacent protected fields  and where a future Northern Bridgwater Bypass might be routed.  Sedgemoor District Council (SDC) have protected in the Local Plan a potential crossing point on the River Parrett just south of the  A38 roundabout at Dunball.

Clearly excavating Chilton Trinity’s fields and creating a series of salt water pits that creates an ideal future breeding ground for salt marsh breeding mosquito’s is not what people have considered the consequence to be. It is far from impossible that in a generation Chilton Trinity and Combwich may ultimately become uninhabitable because of this excavation process rather than from the increased flood risk. Managing mosquito borne diseases may well become the larger challenge in low lying areas as our climate warms up. It is difficult to see how the EA could contemplate the creation of such a situation.

With whole life costs of the Bridgwater Tidal Barrier reaching £100M for a barrier, secondary banks and the raised river banks; banks that need continual raising means we need to consider modification of the delivery model to get the costs of this project under control.

That whole life cost  also ignores the 100 year economic impact,  both locally and nationally, of losing 1000’s  of acres of productive agricultural land  notwithstanding the questionable morality of a food importing country  choosing to export more of its food production offshore. 

If we are going to build the solution we have we need better and more economic delivery solutions than is currently proposed. We can then at least  ameliorate the present situation with a better delivery system.

Brexit allows the modification of the EU water and waste directives  that have now been written into UK law. We can now change the way in which we manage waste for the better.

Sustainable Construction

Every year Sedgemoor will build 5-600 houses and the excavation of foundations and drains for each of these houses will create around 15-20m3 of waste material (clay) suitable for re use as bank raising fill material. Sedgemoor’s  planned housing developments  will create around 9,000m3 per year that currently must be paid for to be disposed of. Housing developers could supply all the material needed to raise the banks. That is sustainable construction.

Over the 100 years life of the barrier there could be as much as 900,000 m3 of material we need to find a home for; material that could be used to build up the banks and preserve the land we have at Chilton Trinity for future generations. Even if the volume is  only 10% of the possible amount its probably enough to avoid digging up land at Chilton Trinity.

Under present EA proposals the EA is going to pay landowners for material that other organisations with similar material must pay to dispose of. We are meant to be reducing this sort of activity not making the situation worse.

We simply don’t need to get all the work in place in 2024; we need just enough to maintain the flood defence need and then use local resources to progressively deliver the longer-term solution with a local benefit to the economy. This work could be collectively done by local contractors under the supervision of either the EA or the Drainage Board. There is simply no engineering need for the EA to wantonly and unnecessarily destroy our landscape when cheaper and more sustainable alternatives are available.

NB there is only an intent to continue to raise the river banks 

To put this into perspective that recycled material would

  • build a bank 5m high bank from the Bridgwater Tidal Barrier to Combwich.
  • raise the banks and build the secondary flood defences up to match climate change.
  • raise the banks, build the secondary flood defence and start building new defences north from Pawlett Hill towards Highbridge.
5m high and nearly 5 miles long, 100 years of digging house foundations

Sea Level Rise

Sea level rise is not expected to slow for at least 300 years making both the barrier redundant as the river banks can only be raised perhaps another metre before they overload the poor ground conditions of the Parrett Estuary. Ultimately the long term plan for Chilton Trinity and Pawlett Hams’s will be realised.

The continued conditioning of the population by the EA to passively accept surrender to the sea as the first option for non-London areas of the UK is disingenuous and defeatist and never mind its land we need to grow food on.

Way Forward

At £100M the present solution for the  Bridgwater Tidal barrier is clearly neither sustainable or affordable. A situation that needs to be laid at the door of the Government, Somerset Rivers Authority and specifically the EA and Sedgemoor District Council (SDC) who provide joint project oversight.  We need

  1. Sustainability in what we do is placed at the centre  of our plans
  2. An independent inquiry into how flood defence is being delivered in Somerset.
  3. A peer review of the BTB project  into how it has arrived where it has.
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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

 

 

 

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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/

 

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Bridgwater Tidal Barrier a Fatal Flaw

The existing Bridgwater Tidal Barrier scheme has a flaw.

Water can go  around it.

Any  system including a flood defence system is  only as good  as its weakest link. The banks of the River Parrett  is the  Achilles heal of the EA’s scheme.

The ground along the river is simply too weak to support the continued raising of the river banks and from the EA’s point of view  too expensive to maintain.  The Parrett’s highest tides hidden behind the  raised banks are already at the top of the doors of Bridgwater’s houses along the A38.

Even before it’s been built and the complete  scheme revealed to the public the  EA is working on adding secondary flood  banks (dashed red lines) on the premise of a bank failure  or  a future decision not to maintain the existing flood  defences. The drawing below is a scheme the EA has to fix the flaw.  The red arrow is the open back door at Walpol where a breach to the north could circumvent all the defences. When the Dutch build a dyke they don’t build another one a few hundred metres behind it; clearly the EA expects a failure to occur or the river to over top.

The line in green is an option never considered  by the EA but one that would offer much better protection than what is being proposed.

EA Secondary Flood Barrier, Downstream Bank Modifications and Alternative Barrier Route

This is information never presented to the public in any of the consultations in 2016.

To my knowledge Bridgwater will have the UK’s  only tidal surge barrier not located at the mouth of the river it’s meant to control. At Bridgwater’s present rate of expansion the proposed  barrier will in 100 years time not be just near the centre of Bridgwater but within  the centre of its developed area. Only in Somerset would anyone come up with  the plan we have and think its acceptable to have a scheme that has such an obvious flaw. Let’s also not forget that the EA’s other wider site downstream is being reserved for a road bridge to  land  that the EA is not  protecting in the same way as existing housing.  What happens when that is to be developed? Start again?

The ratepayer should have had real options presented rather than the EA’s version of  the Henry Ford motto “any colour you like as long as its black”, ie anywhere in the river as long as its at the narrowest part of the river we can persuade people to accept.

The letter below confirms that the barrier can be circumvented.

EA Letter to Chilton Trinity landowner

 

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A Tidal Surge Barrier, A Bridge & Dunball Wharf

One of the problems with building the Bridgwater Tidal Barrier downstream of Dunball Wharf is the marine traffic to Dunball Wharf. Sedgemoor District Councils current draft local plan states “The Council will support the continued operation and potential development of Bridgwater Port including Dunball Wharf and Combwich Wharf (Policy D16 applies). It will also support the re-establishment of active commercial wharf’s at suitable locations elsewhere on the River Parrett. In all cases the construction or operation of new wharf’s should not adversely impact upon the Severn Estuary internationally designated site.”

The reality is that  the Dunball Wharf’s with their tidal drying berths, dependency on  high tides and difficult navigation is never going to be a commercial success but the 200m wide river at Combwich might. Construction of  the tidal surge barrier could enable the relocation of Dunball Wharf to a better location.

Much hangs on what is considered to be adverse.

Concepts of what the river structures might look like have not been forthcoming since 2009. Apart from the tower  and turning vertical gate Bridgwater’s gate structure will be considerably shorter than the Hull Barrier structure we have  been repeatedly shown.

What would a barrier with a road bridge  options look like?

Another wharf at Combwich, EDF have  one there already, would not require an opening bridge or clearance much more than Drove Bridge on the NDR. A tidal surge barrier with a 40m fixed navigation span and a road deck might look like

Keeping Dunball Wharf  would require a one larger gate and an opening bridge. Dunball currently sees 40 or so vessel movements a year so its operation would not affect the bypass traffic.

The engineering is relatively simple and with a purpose built wharf everything could be shipped in during construction.