Anyone here flooded out?

[harryagain]

The usual solution is mini piles.

[chris French]

In message , Tim Streater writes

I was reading something about this a few weeks ago (can't find a link now). The argument was that whilst the changes is dredging practices might have had a marginal effect, if you look at the amount of water flowing through the system lately, then it would have been overwhelemed anyway.

The suggestion was that water is draining from the higher land faster after the rain falls. One thing they were highlighting was the removal of trees, copses etc. which tend to work to hold lots of water and then it gradually drains away slower.

I've no idea of the accuracy of the article, but the idea that we need to look at how the whole system works makes sense.

But of course politicians and the media tend to focus on the simple messages like 'lets dredge more'

Well yes I did wonder that.

[stuart noble]

So much for old churches being safe?

[The Natural Philosopher]

I think the argument is now narrowing down to a removal of ultimate responsibility from river basin drain boards, to the environment agency, and the removal of responsibility from there to the EU, and the general principle that green issues trump common sense when it comes to things like river systems.

there is nothing particularly wrong in letting farmland flood to buffer flows, but the point is you don't want it flooded for too long, or it kills the grass.

Better dredging means you have a better drain and you can pump the water out rapidly.

[chris French]

In message , Tim Streater writes

Years since I read the Nine Tailors so can't really remember it.

Well, yes the fens were drained piecemeal to a large extent I guess, but it seems to work well enough. Can't say that I hear of much flooding out in the Fens

Maybe :-)

It's not just wind erosion, but apparently peat does actually just disappear. Once the area is drained, the peat starts to slowly oxidise and effectively turns to gases and disappears. About half the Fen peatlands that were around 400 years ago have gone now. But apparently the soil leftover still makes for good growing (underlying the fens is clay IIRC)

The post at Holme (South of Peterborough, on the Western edge of the Fens) is a good indication of just how much the land sinks once drained.

The original post (on the right) was erected (or rather inserted - it was flush with the ground level) in 1851 when they started to drain the area. now it is about 4M high. The stays meet the post at about sea level.

Reputedly it is the lowest point in the country, I've never bothered to find out if this is correct

[Peter Crosland]

I am sure that with two successive years of exceptional rainfall the flooding would have been worse this year anyway. Nevertheless the dredging issue is far from being a marginal one that some have suggested. The main, and a many minor watercourses, have been regularly dredged for hundreds of years. The lack of dredging over the last twenty years has significantly reduced the capacity of the river Parrett that is the main outlet to the sea. Judging by what is clearly visible the capacity has been reduced by 60 to 70%. That means regardless of how many pumps are available the volume that can be pumped it limited. The problem has been exacerbated by the very high spring tides that severely limited the volume that can be pumped. At high tide the river Parrett and Tone are running backwards and most pumping has to stop. Meanwhile water is still running into the system and this has to go somewhere.

AFAICS the reason the EA would not admit the major cause was because it would have, and now probably will, open them to significant claims for negligent management of the whole Levels drainage system.

Certainly the effect of how much water is retained upstream is an important factor. However, when there are week after week of heavy rain the entire river catchment becomes saturated. When this happens extra rain simply runs straight off the land and into the rivers.

[chris French]

Yes, yes, keep on bashing your drum.

Indeed not. It's waht flood plains are all about :-)

Indeed, But if more water is flowing into the system than it was designed for, even at optimum operation then you are still stuffed.

I'm not saying dredging is not part of the solution, I just suspect that anyone who says that they have a simple answer probably has it wrong.

[alan]

This is probably part of the ongoing policy of letting salt marshes take the (excess) capacity of (storm) tidal surges rather than building and maintaining ever higher sea walls.

Just because building sea walls was normal for a hundred years doesn't make it the correct solution.

[alan]

Didn't the Daily Express predict the coldest winter in a hundred years?

[chris French]

We are well away from any flood risk (only abut 10M above sea level, but a long way from any river and if we get flooded, there is probably a few

100 sq miles of east anglia much worse off .

There is a section of road, we often use (Earith, for anyone who knows the area).

Every year since we have lived here (8 winters) I think it has been closed due to flooding from the Great Ouse (In effect it is designed to flood, as part of the flood protection)

This is the first year it hasn't been closed (once I went through and the water was part way across the road) Though they did do little bit of work on it last year, resurfacing, taking out low spots, raising the road level slightly I think (as in a couple of inches) to reduce the frequency of flooding.

But I suspect that so much rain has fallen further west that we had no more than normal :-)

[Nightjar]

Possibly trying to flow downhill through the soil but meeting an impervious layer (clay, rock, whatever) that forces it up at that point. It probably normally manages to flow over the top of the blockage but remain underground, unless there is exceptional rain.

Colin Bignell

[Capitol]

Landfill site anyone?

[bert]

Is the right answer Often results in springs. If you're draining land always start at the top of the hill

[bert]

That's the DE's theme tune.

[bert]

And the more houses you build the more floods there'll be.

[bert]

In message , Tim Lamb writes

Many moons ago we had the Rivers Authority who could veto any unsuitable planning application. ISTR it got absorbed into the water boards and then they lost their powers when privatised. Now we have the Environment Agency. Run by the tosser Lord (Chris)Smith who was useless as a government minister and so was promoted to the Lords.

[Nightjar]

I think you rather missed the point.

Colin Bignell

[bert]

In message , Martin Brown writes

Well Climate Change has become more like a religion than a science. Chant the mantra "The science is proven" and denounce anyone who questions it as "deniers" or infidels.

[bert]

In message , chris French writes

Nothing drains water away faster than a house roof. The fields around here, which they are planning to build on currently are saturated with water.

..And don't build on flood plains.

[charles]

only if the dredging allows a greater flow of water. If there's a sluice or weir in the way dredging can't have much of an effect.