Non-motoring > Building On Floodplains Green Issues
Thread Author: zippy Replies: 9

 Building On Floodplains - zippy
The spokesperson for DEFRA or similar said building on floodplains is silly. No **** Sherlock!

A new 3 mile long £120 million single carriageway road has been built right across a valley floor which floods every year. The purpose of the road is to open up land in the valley for development - housing and businesses! Never mind that its an area of special scientific interest and natural beauty.

Elsewhere a colleague purchased a very expensive house only to find a bill for £200 p/a land on his door for pumping services - the estate gets flooded and the builders fitted a small pumping station and the running costs are several thousand a year, shared amongst the houses. All OK until it goes wrong!

What are the planners on when they allow this!

BTW, just north of the town is an equivalent area of land that is not on a floodplain. There is a road there and some large private estates. It would have been far more suitable for development but the local / county council did not own the land. Why didn't they use it? More expensive to buy the land I guess.
 Building On Floodplains - smokie
"No **** Sherlock!"

My daughter used that exact phrase in response to this news item last night. I'll have to go and look up it's derivation now.

I do some modest walks around town and a couple take me past (dry) overflow lakes near new housing estates. (I forget the exact terminology) but I've assumed this is is designed to take some excess when the water level rises.
 Building On Floodplains - PeterS
Are they called attenuation ponds? Or at they something else perhaps...?
 Building On Floodplains - sooty123
We've been building on floodplains for a long time, it's nothing new. Everything is a balance of building where people want homes and how hard it is to stop those homes being flooded.
 Building On Floodplains - Zero
all the thames valley is a flood plain, London is a temporarily drained and managed river delta..
 Building On Floodplains - bathtub tom
They built on a floodplain in my town decades ago, I couldn't believe it. Thanks to modern river control it hasn't flooded in forty-odd years.
There are circumstances when it would seem acceptable, although I wouldn't want to live there.
 Building On Floodplains - Zero
>> Thanks
>> to modern river control

There is no such thing really, for several reasons. The weather patterns for which river control has been planned are no longer valid. Controlling a river in one place means a knock on uncontrolable event up or down stream. Given a sufficient period of time, every river will at some point find its old path again. Coastal flood defences ditto, specially with reference to moving issues elsewhere.


There is only one way to live with flood conditions, construct infrastructure to mitigate the effects. Buidlings designed to quickly shrug off floods, build on stilts, raised roadways, fast flow channels etc etc.

With reference to changing weather patterns, flood management needs a completely holistic approach, managing the land and water from above source to sea. Building on flood plains has made flooding worse as the natural expansion areas have been reduced. Piecemeal control, our current approach, wont cut it.
Last edited by: Zero on Wed 26 Feb 20 at 09:45
 Building On Floodplains - Manatee
Yes we have always lived and built on flood plains.

Much of East Anglia would be under water without constant pumping. As folk on here will know, west and south of the Wash there is a massive system of ditches and dykes, feeding forty foot drains and the hundred foot drain from Earith to Denver whence the enlarged and embanked Gt Ouse conveys water into the Wash.

The system depends more on managing water in flood than in physically preventing encroachment. There are designated areas of storage, productive land that is deliberately flooded first to reduce damage. Further east the water from dykes is pumped up into the broads from which in flows via rivers to the sea. Flooding is tolerated and managed to mitigate its destructive effect in all but the most severe events.

Elsewhere and more recently there has been more effort to build hard structures to keep water out but this become exponentially more expensive as flood levels rise, so the EA and local lead flood management bodies like county councils have been looking towards natural flood management (NFM). This is more about managing flows and increasing storage so that water flows downhill to critical points more slowly in times of high rainfall. Round here there is a baying mob ready to lynch the LA for not clearing ditches but the fact is that if all the ditches were cleared indiscriminately then in many cases the water would just travel more quickly and in greater volume to the houses that flood. There has to be somewhere for the water to get away at a rate close the the rate it arrives at.

A few years ago half my garden was covered by the flood risk area map. For some reason, and I am a bit supsicious, it now isn't and although my garden still floods neither it nor the house are in flood zones 2 or 3 which are relevant for planning! From an insurance and saleability point of view of course this is a good thing. As I am about to demolish and rebuild I will still put the new house about 10cm higher than the old one as a bit of extra insurance.

 Building On Floodplains - Zero

>> The system depends more on managing water in flood than in physically preventing encroachment. There
>> are designated areas of storage, productive land that is deliberately flooded first to reduce damage.

Welney is a classic example, between the new and old Bedford Rivers (rivers they aint - man made they is) and area designed as water catchment, but it always features heavily in the news when peeps try and take the road through the middle during planned flood times, and its always a shock news item, tho all the locals know its designed that way.
 Building On Floodplains - John Boy
I'm assuming that Zippy refers to the A2690 which links the A21 on the north side of Hastings to Bexhill. I've just looked it up on the Government's flood plain map. The road is visible, cutting across the high risk area, but dissappears when you zoom in.
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