Ahead of the forthcoming last public consultation on the Bridgwater Tidal Barrier (BTB) the rate and tax payers might consider asking what becomes of Bridgwater after the BTB reaches the end of its design life?
The answer is simple.
if there is no barrier capable of keeping the rising sea out there will be no house insurance, no mortgages and Bridgwater the town will not be a viable place to live.
Our present proposed EA flood defence scheme is based on retreating as far back from the sea as we can, it deliberately puts our backs to the wall On one side of the barrier we will ultimately have the inter tidal habitat (the sea) and on the other our housing and industry.
No space is being provided behind the proposed barrier to create another bigger one. As a consequence there will be nowhere to go with a replacement that does not have a huge and unnecessary price tag. There is an irony that land at Chilton Trinity returned to the sea under the present scheme and the planned managed realignment in 2055 will be inadvertently reclaimed under a downstream replacement barrier albeit land now poisoned with salt.
With sea level rise continuing for hundreds of years past the design life of the BTB one would expect that as responsible people we would give some consideration to what happens next. Unfortunately, like so many things in need of fixing and investment we seem content to kick the problem into future refusing even to consider how we might make some provision to help those that follow us.
Many years an Arup engineer called Poul Beckmann wrote the opening sentence of a document with the line “Human nature is that we put off until tomorrow what we should do today”. Never has that been more true today than in Somerset. Somerset’s failure to develop a realistic, affordable and sustainable long-term strategy is unforgivable. It really is time for some of the promises made by our political leadership on this issue to be delivered and people stop making excuses why things cannot be done. Simply working our way through the Somerset 20 years plan and saying the future is not our business is irresponsible and unacceptable.
what was the question?
The SRA was asked “What is the SRA and its partners working assumption for the replacement of the existing scheme and barrier?
The written answer received from the SRA answer is in blue
From day one, the tidal barrier will be designed in such a way that it will still provide a 1 in 1,000-year standard of protection in 2125. The design includes an allowance for climate change up to 2125.
- Climate change does not stop in 2125!!!!
- 1:1,000 sounds good but its just the margin on the starting point and degrades over time. The Dutch use 1;10,000 and maintain it as the level of protection.
The downstream defences will be designed in such a way that they will still provide a 1 in 200-year standard of protection in 2055, with allowance for further adaption for climate change over time.
- 2055 is important because this is the date from which managed realignment is implemented under Policy 7d39 of the Shoreline Management Plan.
It is to be expected that any piece of infrastructure would need updating after 100 years. We cannot decide now how future generations may wish to live or what their priorities for infrastructure will need to be. This is why, for example, there are plans for the Thames Barrier to be re-built in future decades but decisions on exactly where and what will be required are deliberately being left for later.
- Building the barrier in the town as planned does not give those in the future choices but leaves them no choice to but to go downstream and use land we have previously given back to the sea and to abandon the £100M investment the present scheme will have cost.
- The response attempts to conflate the need to replace the 1970’s Thames Barrier as a reason not to make provision today for a replacement in Somerset. if you know you have to replace something why would you not plan for the replacement? Its an excuse.
- We should be learning the lessons of the past rather than making a virtue of repeating the failures that the SRA reply implies.
The Thames Barrier Myth
The continual portrayal Thames Barrier shown on TV as an iconic single barrier solution is misleading; the barrier is actually part of the Thames Estuary flood defence system comprising not one but eight individual tidal barriers that all shut together. Five of the eight barriers are closer to Bridgwater’s situation than the “Thames Barrier”. They are however where they should be at the mouth of the rivers they defend not 5 miles upstream as with Bridgwater’s Tidal Barrier.
Using the Thames Barrier as an excuse for not planning a replacement in Somerset is particularly disingenuous for a number of reasons.
- Nearly 60 years ago when the Thames Barrier was designed climate change was not understood as it is now. There was little provision for sea level rise just the post Ice Age tilt of the south of England to consider.
- The Thames Barrier is upstream of what were active docks that had navigation rights in the Thames Estuary.
- In Somerset we have a topography in the form of the Polden Hills, Pawlett Hill and Stockland Bristol that we can link and use to our advantage. London does not have such a luxury.
- All the Thames Barrier replacement options move the replacement barrier downstream perhaps as far as Tilbury. (July 2016 update)
- The most frequent use of the Thames Barrier is now the management of fluvial flood water rather than tidal surge. Something Bridgwater is not designed to do.
- Sedgemoor District Council is able to reserve space for a bridge over the Parrett south of Dunball should its not be doing the same for a replacement barrier?
The collective response is No ; there is no plan.
The SRA, EA and SDC were conformed as having contributed to the response
Bridgwater Tidal Barrier; the Questions the public need to Ask
Once the question “how will the proposed Bridgwater Tidal Barrier be replaced?” the present scheme simply looks out of date and poor value for money.
The Bridgwater Tidal Barrier is repeating the same mistake as was made with the Thames Barrier system setting it as far upstream as possible. Because of the selected location a replacement would like the Thames Barrier have to go downstream towards Combwich. Confused? We should be.
When you go to public consultation some questions worth asking;
- How will the proposed Bridgwater Tidal Barrier be replaced?”
- What becomes of Bridgwater after sea level rise exceeds the design basis of the Bridgwater Tidal Barrier?
- Why is there no long-term plan or vision for what comes next?
- Why is the ratepayer required to provide money to raise river banks money protecting land at Chilton Trinity when the planned sea water flooding will make it of no economic value?
- Why is not improving fluvial flow in the river system part of the scheme?
- Why did the cost of the scheme almost double after the location was decided on?