For those of you who are not aware, following their initial application in 2012, CEMEX have presented revised plans for gravel extraction at Watersplash Farm which are due to be presented to the Surrey County Council Planning Committee either in April or May this year.
Local residents have serious concerns about an increased risk of flooding within Sunbury and Shepperton as a result of this development.
We urge you to read this article carefully and consider whether you wish to take further action. If the findings of our qualified technical advisors are correct then this development will almost certainly affect you in terms of increased flooding, higher insurance premiums and planning restrictions for extensions etc.
This is to say nothing of the volume of 20+ ton lorries which will descend on our roads estimated at 225,000 lorry passages overall which we estimate to amount to 280 per working day (SCC already admit to 200 per day).
CEMEX will excavate approximately 1.2 million tonnes of our precious gravel and back fill with landfill material, which they claim will be “inert and free from pollution”.
Why is the gravel so precious to us? It forms the subsurface material through which groundwater can flow during heavy rains out to the rivers, where it is whisked away to the sea by the fast flowing Thames.
The gravel is only a thin layer (less than 10 metres thick) and sits above the London clay which is impermeable. So over the passage of time it has served us well as a hidden ally to distribute rainfall and flood waters out to the river system. It is our natural flood defence in an area of already high flood risk (flood zone 3: high risk of flooding).
Yet CEMEX want to take our main flood defence away and fill the hole with impermeable clay and building waste material and as things stand Surrey County Council intend to let them!
We need your support to stop this application
So why is SCC intent on using such an ill-advised location for this project? SCC have a requirement by the Government to supply gravel for infrastructure building projects, roadways and the like and since you can only find gravel where it lies (our area is rich in gravel). We have drawn the short straw. But the Government also say that you can’t extract gravel if it will increase the risk of flooding in the neighbourhood. In fact they go as far as to say that vulnerable areas (for example flood zone 3 with local permanent mobile homes) should not be touched! Sounds familiar, just look at Fordbridge Park mobile home site, across the road from Watersplash Farm!
SCC know this and so by starting with the foregone conclusion that there is “no additional flooding risk” CEMEX have done the job of providing confusing and contradictory plans to suit their aims.
We think this is a flooding disaster waiting to happen, a view confirmed by two flooding specialists on our team, namely a qualified Civil Engineer, John Fennell, and a practising Geologist specialising in earth sciences, Lewis Reece. They believe that the effects of removing the permeable gravel and replacing with impermeable clay will be to block groundwater flood flows and distribute the water elsewhere: that elsewhere is Shepperton and Sunbury.
The height of Watersplash Farm is approximately 6 feet above the outlying areas. Look at the ground level of Watersplash Farm from West Way, adjacent to Gaston Bridge Road and you will see what we mean.
Surely the authorities like the Environment Agency are dealing with this? The EA have in the past objected and insisted on various measures, however in March 2016 the EA became no longer responsible for surface water drainage, only river based flooding. Responsibility for groundwater flooding passed to the Local Lead Flood Authority and this is Surrey County Council!
Surely SCC and CEMEX will have taken measures to prevent flooding? Yes, naturally they have had to complete a flood risk assessment and have proposed mitigation measures in the event of flooding. In fact SCC now claim that they have, “a robust monitoring plan, contingency action and planning conditions”.
Our experts were not happy with this, so SCC was challenged. To which they hired a hydrological consultancy firm, Peter Brett Associates, (PBA) to counter our claims. We asked to see their report under Freedom of Information (FOI) rules but SCC refused. However, it was disclosed that the response from PBA was simply an email. There was no analysis carried out by SCC or PBA. In a case such as this don’t you think that they should at least have carried out 3-D modelling to simulate the effects of removing our main flood defences?
At least the project will only be lasting a few years: Not so! The damaging effects of this project will last forever! Once the gravel is removed and replaced with an impermeable clay brick we will face the consequences for ever after. Long after CEMEX have gone and left us with the consequences.
And what about climate change? SCC’s hydrological consultants PBA wrote: “In terms of a design event the 1 in 100 year (1% per annum) is used for fluvial flooding with an additional allowance for the impact of climate change over the lifetime of the project.” Note the words “over the lifetime of the project”. As we know the project is temporary, due to last some five to seven years. However the infill will be permanent and hence its effects will be permanent. It is therefore a sleight of hand and false to estimate the effects of climate change over simply “the lifetime of the project.”
The Watersplash area is at high risk of flooding due to climate change and is adjacent to highly vulnerable areas such as Fordbridge Park mobile home park. In the planning application Cemex must account for the effects of climate change on their development as it is a development that will be in place permanently. This means they must fit the peak river flow allowances into their models and assumptions which show a 70% increase for 2070 onwards. They have done nothing to account for this, nor would they wish to as this alone would show clearly adverse flooding effects from this foolhardy project!
Please respond to this application now – for your own sake! We have prepared a response form, which you can use as a template and the address to send it is at the bottom. See online magazine for details
By John Douglas and Richard Hewitt