Flood prevention

[Guest Alan Taylor]

Holland 1953,141,000 hectares under water,

49000 houses and farms under water. 8250 properties totally destroyed. 100,000 to 110,000 people evacuated.

 

1835 Dead.

 

Now unlike the UK, the Dutch people did not just sit on there sand bags, they built one of the best flood prevention schemes in the world. When I say the people, I mean that besides the big construction firms work force, the people chipped in and helped for free.

As well as being efficient these flood prevention schemes are also tourist attractions.

We do still get some minor flooding as the Rhine and a couple of other rivers bring the water from Germany and most of Holland is below sea level.

If the Enviromental (yes, I know) Agency would like to try taking a look at how to save lives, property and money, let alone the missery, I would suggest they come over here for a week.

 

I live in Holland but still get angry when there is a solution to a problem and nothing is done about it.

 

I hope your weather improves and you get back to normal until the next bit of rain.

 

Alan(NL)

[Guest Leon Roskilly]

Originally posted by Alan Taylor:

Holland 1953,141,000 hectares under water,

49000 houses and farms under water. 8250 properties totally destroyed. 100,000 to 110,000 people evacuated.

 

1835 Dead.

 

 

I remember that.

 

A couple of hundred died in the UK as well .

 

A low pressure system swept into the North sea. As it did so, the SW winds pushed back the tide into the dome of seawater (which forms beneath low pressure systems) out toward the North.

 

There was no high tide that day, along the Essex coast.

 

The low pressure headed eastward, onto the continent, it's wind becoming North Easterly pushing the next tidal surge south, swelled by the collapsing pressure dome of water, now being pushed down by high pressure.

 

As all of that water headed south down the North Sea, the surge, compressed by the narrowing gap between the English and Continental coasts, rose higher.

 

The sea defences began to fall, the Essex coast taking the brunt, Canvey Island being completely overwhelmed.

 

Many lives had already been lost, and much worse was threatening - then the wind changed to the North West, the tidal surge was deflected toward Holland. This capricious act of god spared many English lives, at the expense of the Dutch.

 

Look at our sea defences, most of them date after 1953. Others have additional protection atop, again added since 1953.

 

But that was all before global warming, and many are now beginning to crumble badly.

 

Often, 'hard' sea defences mean that the problem is merely diverted (The Thames barrier is a monument to the willingness to sacrifice those down river to protect Londoners). They also cost a lot of money, and mean that, as the sea advances toward them, precious marginal habitat is lost.

 

The decision is to largely abandon the concept of hard defences, and to allow the sea to 'reclaim' land, the land and sea responding naturally, by creating 'soft' defences; salt marshes and shingle beaches, tossed up by storms, inland of their present positions.

 

A lot of east coast land will be lost, an awful lot of East Anglia - but the solution is cheap, environmentally beneficial, and bows to the inevitable.

 

But, god help us when the next 1953 happens. With the onset of the consequences of global warming, storm situations which previously occurred (say) every 500 years, are likely to occur (say) every 50 years.

 

Our politicians and planners may be comfortable with the concept of 'managed retreat', but will they be when the next big tidal surge and major storm conspire together to overwhelm what defences we have left?

 

Managed retreat is expressed in metres of coatline per year, that's a comfortable average figure! When a single event moves the sea forward by the combined average of several decades, the consequences may not be so comfortable.

 

Tight Lines - leon

 

ps It's nothing to what's likely to happen next time a Norwegian fjiord collapses.

 

It certainly cleared the (agricultural) viking colonies from the East coast of Scotland last time! And they were quite a height above sea level.

[Guest Steve Burke]

Originally posted by Leon Roskilly:

It certainly cleared the (agricultural) viking colonies from the East coast of Scotland last time! And they were quite a height above sea level.

 

Was that caused by a tidal wave, Leon?

 

 

 

------------------

Wingham Fisheries

www.anglersnet.co.uk/fisheries/wingham/htm

[Guest Leon Roskilly]

Originally posted by Steve Burke:

Was that caused by a tidal wave, Leon?

 

'Tidal' isn't strictly correct (the pull of the moon not being involved) but yes, according to popular conception of 'tidal' waves.

 

Archeologists had discovered the remains of the thriving settlements, and had presumed that climate change had bought them to an end.

 

But all the evidence showed that the communities had disappeared quite abruptly.

 

They also found a lot of sea debris (shells etc)laid down about the time of their disappearance. Puzzling because they were well above sea level.

 

Then the theory of a sudden tidal wave was considered, and a lot more supporting evidence for that become apparent.

 

I'm not sure what firm evidence exists for a collapsing Norwegian fjiord being the cause, but the article I read said such an event could happen again at any time.

 

There are a number of risks of huge 'tidal' waves crashing their way across the sea.

 

I wouldn't like to be standing on the beach in Australia, when Los Angeles slips into the sea, or along the east coast of America, when part of the volcanic Canary islands shelf collapses!

 

Tight Lines - leon

[Guest Leon Roskilly]

A small piece in this week's new scientist caught my eye.

 

Apparently changes in farming practices over the last 20years could be contributing 20% to the flooding.

 

Dick Thompson of Crangield University's Soil Survey and Land Research Centre is quoted as saying 'There is less organic matter in soils than there was 15 years ago. We know that causes a hard cap to form on soils, which prevents water infiltrating into the soil.'

 

Geoff Mance, director of water management at the EA says 'Farmers used to plough their fields and leave them bare through winter, so water collected on the land, filling furrows and infiltrating into the aquifiers beneath. Now they mostly plant winter cereals, sometimes without ploughing at all. Rainwater drains straight of the resulting smooth surface. We have a huge acceleration in the speed that rainwater flows into rivers, causing big flood peaks after storms'.

 

Mance also wants town planners to insit on permeable pavements that soak up rain-water, more urban lakes and making developers reduce run-off from gardens, driveways and car parks.

 

I know of several town ponds which were drained, filled, and concreted over in past years. Maybe they will start digging them out again!

 

Tight Lines - leon

[Guest fisherman]

What about in years past when the fields were a lot smaller, look at the amount of hedges that have grubbed up, trees cut down to make the fields easier to get around. Admitedley some farmers are replanting small copses back on their land to encourage bird life but this isn`t enough to suck up some of the rain fall the hedges did. There used to be ditches around some fields as well for drainage, none of this helps.

Dave

[Guest Darth_codhead]

Bring this back to life to see what happens

[Guest Silversurfer]

Originally posted by Darth_codhead:

Bring this back to life to see what happens

 

Everyone should have a dyke.

 

 

 

------------------

Silversurfer

Guardian of the stars

[Guest Newt]

Thanx Darth. I missed this one the first time around and it is a great thread.

 

Originally posted by Leon Roskilly:

I wouldn't like to be standing on the beach in Australia, when Los Angeles slips into the sea, or along the east coast of America, when part of the volcanic Canary islands shelf collapses!

 

In preparation for when, not if, the southern section of California sinks, I've bought some land in western Arizona. It is all sand now - part of the Sonoran Desert but I'm hoping it will become beach front property at some point.

[Guest Steve Burke]

What worries me is how much warning would we get if a fjord or something similar collapses? Just imagine the traffic jams trying to get to higher ground!

 

------------------

Wingham Fisheries

www.anglersnet.co.uk/fisheries/wingham.htm