Monday 8 June 2015

Grillo Site - The Once and Future Flood Plain

Some years ago I had the experience of trying to oppose a development at Stradey Park. It was on a C2 flood plain (the worst sort, for those not fluent in environmental classifications). Suddenly the Environment Agency reclassified the flood plain as a C1 (the still bad but slightly less bad kind) and Carmarthenshire County Council Planning Committee decided to pass the application, provided the flooding could be prevented by raising the site. Then, suddenly, the flood plain returned to a C2 again, actually now bigger and more hazardous than originally. These sort of things happen when a huge amounts of money is involved, a sort of special governmental magic.

Today I find myself looking over the Grillo Site in Burry Port with a sense of deja vu. It was partially covered by a C2 flood plain, Then it wasn't. In fact it's now newly classified as a grade A - highly unlikely to flood. But still the land around on and aound the Grillo site has to be built up to prevent flooding. What is going on with the Welsh environment these days?

Wading through the documentation you will find that although the site isn't a flood plain now, it is going to be one sometime soon. Houses are supposed to last 100 years and although the chances of the old chemical factory site flooding tomorrow are apparently zilch, the chances of it flooding sometime in the next 100 years are very high. Why?

Because the sea level is rising and in 100 years time is conservatively predicted to be over a metre higher in the estuary than it is now. If global warming continues to cause massive ice melts and extreme weather events and the area still has its heavy rainfall, the new houses will have to be over 7 metres above sea level to be guaranteed to stay dry at all times in the next 100 years. I suspect that part will not be covered by the estate agents.

So there isn't a flood plain now, but there will definitely be one later, and a particularly bad one at that. When exactly this will occur depends on the speed of global warming. The sites will all be built up and the reports admit that this is likely to cause some flooding in other neighbouring areas as water is displaced away from the new buildings, much like the way a bathtub will be at the perfect level of fullness but will overflow once someone climbs in. Interestingly, the decontamination plans for the Grillo Chemical factory site do not appear to take the future flooding and raising of the land into consideration.

I'm Councillor for the Llanelli Ward of Hengoed, immediately to the east of this development site. All of the lower lying land in my area was reclaimed from the sea many years ago in Victorian times. All of our streams and rivers are already "tide locked" to prevent flooding. When the tide comes in a huge flap valve closes over the mouth of every watercourse to prevent the sea coming in and stop the river flowing out. If the tide is high, the flap stays closed longer and we occasionally get back flooding from the rivers, especially after heavy rain, producing a high water table. In some areas the water is just perculating upwards from the soil, in other places streams and rivers are flooding over their banks and/or drains are just unable to cope as the watercourses are effectively blocked twice daily by the tide.

The general policy from Welsh Government is "hold the line" and probably there won't be either the will or money to actively preserve the low land in Llanelli by installing a massive active pumping system to pump the rivers out over significantly higher sea defences. Already some unpopulated areas upstream are deliberately being returned to tidal marshes to try to mitigate floods - an option not available for a town built to the water's edge.

Llanelli has thousands of homes on the low lying flat areas already below sea level. Some are new ones being constructed as I write this. The proposed elevated homes on the Grillo site are safe for a hundred years, we are told, but then considering the age of your average councillor, perhaps they're simply not thinking that far ahead anyway. They certainly don't seem to be thinking that if the sea is going to rise over a metre at Burry Port, its probably going to rise just as much off neighbouring Llanelli.

Cllr Sian Caiach

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