Too much water?

[cee-dee]

I've been thinking.... (OK, so thinking's a bad idea?) about all this water we've had and the poor unfortunates that have been flooded.

Now, if you've got a pipe and it's full of water, it's full and if you try to put more water in to it, where you're trying to put more in, it will just not go.

Streams and rivers are not constricted like a pipe, I suppose they're more like half a pipe? So when they're full and more water is put in to them, the water spills over the sides. There's absolutely no way you can constrict it. OK, so you build the banks up and what happens? The extra water backs up all the storm pipes leading in to that water course?

Someone could say "Ah-ha, we can deepen that water course" but what'll happen then? I suppose some group or other will counter that by saying "Oh no ya don't, there's all the wriggly things that live there, oh no way can you do that"!!!!!!!!!!!!

What do we do? Put all the properties on stilts? Knock 'em all down and move the communities? Where to?

So, what's the answer then? What bright ideas can anyone come up with?

[right-then-petal]

Stop Putting Housing Estates And Factories  Sports Grounds Where Water Would Normally Soak Away

The More Concrete You Layy Down The More Pipes And Drains You Need, Then When It Rains Hard The Water' s Got Nowhere To Go Bar On Top Of The Concrete

PS

Theres Going To Be A Lot Of Treasure Washed Up On Beaches, One 80 Ft Ship Missing For 2 Years Has Been Blown Ashore In Northern Ireland

[cee-dee]

That's also very relevant Petal but some of the communities that've been flooded don't have that sort of development upstream.

Don't think there'll be many treasure hunters going aboard that old ship? Seen the size of it?

[astrologica]

In the Summer we will be having a drought, and hosepipe bans. Why are we not building reservoirs and diverting some of this water into them? That would probably cost less than putting right all the damage to people's homes and vehicles etc. Just an idea.

[cee-dee]

Any suggestions of building a reservoir today will be met by even more howls of protest than deepening the rivers.

What people forget is that a lot of the rivers weren't always as "deep" as they are now, they spilled over the land much more.

[right-then-petal]

https://www.bbc.co.uk/news/in-pictures-51558440

[cee-dee]

Petal has now disappeared because he is now packing for his trip to Ireland to salvage what he can from the ship to sell at the car boot sales and on ebay 

[upthecreekyetagain]

Deepening rivers is hardly going to help with the recent conditions!  All that does is move the water faster into those areas unable to cope with it.  Nature has the answer,  flood plains, built up over the centuries by the depositing of silt from when rivers have broken their banks.  Land which developers now consider as some of the most valuable and desirable because of their location.

When this land is developed the houses built are normally quite safe from flooding, land is raised, the latest drainage solutions are installed etc.  The result is that the water can no longer sit on the flood plain and slowly disperse as the weather improves but again, as with river dredging, travels further downstream where it does far more harm.

This is a photo taken from the bottom of our garden showing where over 2,000 new houses are being built and perfectly demonstrates the above.

This is our side of the river which is part of the flood plain

You can see the river in the far background and the new houses close to its bank on land that has been raised   

[cee-dee]

Great idea building on a flood plain:-

https://www.onthemarket.com/content/buying-house-flood-risk-area/

[cee-dee]

Oh dear, why did they build on a flood plain?:-

https://ichef.bbci.co.uk/news/624/cpsprodpb/318D/production/_110958621_hi060006989.jpg

[upthecreekyetagain]

Building on a flood plain is often quite safe for the new buildings - modern flood protection for new builds can be very effective - the problem is that this shifts the problem down river to areas that can't cope with the extra water.

Leatherhead is about 15 miles downstream from us and has suffered badly from the recent rains - reducing the flood plains upstream, (this includes the vast expanse of concrete that is Gatwick Airport), can't have helped.

https://www.surreycomet.co.uk/news/18240754.flooding-hits-surrey-wake-storm-dennis/

[cee-dee]

Quite safe for new buildings? After watching some new builds going up, I don't think so.

There's no foundations as such, they build on a concrete raft. Then the "walls" are pre-constructed off site and made of timber frames, not substantial timber though. Once the "walls" are errected, the roof is put on made of pre-constructed trusses gang-nailed together. After that, the outer walls are skinned with brick.

That's going to be a bit of a nightmare if flooded?

[upthecreekyetagain]

The thing is though that all sorts of protection are constructed to protect new builds in flood risk areas.  

[cee-dee]

You best try telling that to those having new builds with a few feet of water in them.

[upthecreekyetagain]

Not sure where you're thinking of but all the flood reports I've seen aren't ones of new build houses. 

[cee-dee]

Look what they're doing:-

https://www.theguardian.com/environment/2020/feb/19/one-in-ten-new-homes-in-england-built-on-land-wi...

https://www.independent.co.uk/news/uk/home-news/flood-land-homes-houses-insurance-development-cpre-a...

https://www.bbc.co.uk/news/science-environment-50419925

https://www.dailymail.co.uk/news/article-8023835/One-ten-new-homes-built-land-risk-flooding.html

[upthecreekyetagain]

All those reports reinforce the point I have been making - far too many houses are being built on flood plains - not one of those links show however that the houses that are/have been built in flood areas have actually been flooded.  They are unlikely to be flooded when land they are built on is raised, the latest drainage systems are installed and bunds are built around them.  

Those types of measures do protect the new houses but at the same time displace the water to areas that may not have previously been affected by floods.

[cee-dee]

You can't raise the land above flood level because some low lying areas have got six feet or more water on them at the height of the floods. As far as raised bunds are concerned, there'd have to be quite sophisticated (expensive?) drainage systems incorporating pumping. Water pressure backs up the drains and flooding then comes from the drainage system.

Raising the land level means building on made-up ground so what sort of (expensive?) foundations will be required?

The sensible solution is to deepen the rivers, drainage channels and ditches!

[upthecreekyetagain]

I'm no engineer but the proof of the pudding is that there don't seem to be reports of new build developments having been flooded despite apparently 10% of new houses being built in flood risk areas according to the links you provided.  

How they do it I don't know but if you look at the photos I posted you can see that the water on the other side of the river to us where the new houses have been built is relatively dry.  In the past that side of the river had as much surface water as our side.  Hundreds of lorry loads of hardcore and crushed concrete was laid down after piles had been driven in.  The ground on that side of the river must be at least 5 foot higher than previously.

I was listening to a water engineer on Radio 4 today and he was suggesting that putting debris in a river, (such as broken branches etc.), which slow down the flow helps reduce flooding downstream.  The idea of deepening and widening rivers intuitively looks like a good idea and certainly reduces flooding in the immediate area and upstream of the works - but all it does is move the problems downstream.

[cee-dee]

So how much did the houses sell for on that development near you?

As to moving the problems downstream, surely you continue the dredging all the way downstream?