Another series of lows and Storm Dennis

[WotEver]

Just now, TheBiscuits said:

I don't think incinerating dredging spoil is much of an improvement!

No... you compost it. It’s the new thing, don’t’cha know

[TheBiscuits]

Just now, magpie patrick said:

My understanding is good enough to say "it's not that simple", I sub-contract to the real experts to get the answers

I thought we'd had enough of experts ... We want freaks and weirdos now, apparently.

 

I'm not entirely sure it will help.

[WotEver]

1 minute ago, magpie patrick said:

It would be good if fluid dynamics in flood were as simple as that - they are not

 

A crude model will use the capacity at the weir, a more sophisticated one will look at dimensions of the river as well - and any model may be inaccurate when conditions push the envelope of the model. 

 

My understanding is good enough to say "it's not that simple", I sub-contract to the real experts to get the answers

Okay, I’ll leave it to they “It’ll help” “No it won’t” factions to argue amongst themselves for now then. 

[TheBiscuits]

3 minutes ago, WotEver said:

No... you compost it. It’s the new thing, don’t’cha know

I thought your main objection to composting was that it mostly goes in the bin, so we are back to landfill again ...

[blackrose]

I love this sort of thing  Suddenly a bunch of canal boat forum members become river and flood management experts! ?

 

It's the same in my field of expertise (food packaging materials and environmental science). Because it's become a hot topic suddenly everyone is an expert. I'd never dream of telling a teacher or social worker about their job but for some reason they have no problem telling me about something of which they clearly have no knowledge.

 

Edited February 24, 2020 by blackrose

[TheBiscuits]

You can say that again ...

[blackrose]

Duplicate

Edited February 24, 2020 by blackrose

[Alan de Enfield]

2 minutes ago, TheBiscuits said:

You can say that again ...

 

3 minutes ago, blackrose said:

I love this sort of thing  Suddenly a bunch of canal boat forum members become river and flood management experts! ?

 

It's the same in my field of expertise (food packaging materials and environmental science). Because it's become a hot topic suddenly everyone is an expert. I'd never dream of telling a teacher or social worker about their job but for some reason they have no problem telling me about something of which they clearly have no knowledge.

 

 

[WotEver]

28 minutes ago, TheBiscuits said:

You can say that again ...

That

[sirweste]

4 hours ago, peterboat said:

Cobblers to the report is all I can say, its the cost of dredging they are trying to avoid!

The Don and Rother for most of the time are empty and severely blocked along their lengths so as it rains they fllod by 4 to 5 feet if the were at their proper depth  the full length they wouldnt flood same as the river Hull which is under a third of its size and depth

 

3 hours ago, Dr Bob said:

I've not read the report (where's the link?) but I would have thought dredging has to help.

If you take out 100 cu metres of crud from the bottom of the river then that river will then take 100cu metres more water at that point to achieve the same level. The question then is how much water causes the flood and can you dig that much out. I think that we should review the policy on dredging and accept the crud can be spread on the land. Are our fears of contamination too extreme? (which would then make the economics of dredging far more advantageous to flood defences which only serve to move the water downstream to the next unprotected flood plane).

 

1 hour ago, magpie patrick said:

We had this argument in Somerset 6 years ago - the pattern is not disimmilar

 

Stop dredging, 20 years later there are unprecedented floods, but apparently not dredging wasn't the issue

 

Then, without actually admitting anything, the EA dredged the rivers again....

 

A lot of the problem is the difference between theory and practice - the theory saying that dredging for 200 plus years wasn't necessary, experience says otherwise

 

Sorry, here's the link, couldn't think where it was earlier.

 

 

@Dr Bob you're right, the key bit of the question is how much water causes the flood. he images show many many litres spread across land, a bit of dredging isn't going to make much of a dent in that

Edited February 24, 2020 by sirweste

[peterboat]

1 minute ago, sirweste said:

 

 

 

Sorry, here's the link, couldn't think where it was earlier.

 

 

@Dr Bob you're right, the key bit of the question is how much water causes the flood. he images show many many litres spread across land, a bit of dredging isn't going to make much of a dent in that

Sorry just because the EA doesnt want to do it doesnt make it right, for hundreds of years we dredged and we didnt flood now we dont dredge and we flood hopefully Boris will be having a chat on his phone about itto someone shortly telling them the same!

[sirweste]

1 minute ago, peterboat said:

Sorry just because the EA doesnt want to do it doesnt make it right, for hundreds of years we dredged and we didnt flood now we dont dredge and we flood hopefully Boris will be having a chat on his phone about itto someone shortly telling them the same!

OK

[ditchcrawler]

2 minutes ago, peterboat said:

Sorry just because the EA doesnt want to do it doesnt make it right, for hundreds of years we dredged and we didnt flood now we dont dredge and we flood hopefully Boris will be having a chat on his phone about itto someone shortly telling them the same!

Maybe we didn't have houses all over the flood plains or all the arable land just flattened off for acres? not forgetting we seem to be getting more heavy rain, a lot less trees and banks. Nothing except not dredging has changed over the past 200 years

[peterboat]

2 minutes ago, ditchcrawler said:

Maybe we didn't have houses all over the flood plains or all the arable land just flattened off for acres? not forgetting we seem to be getting more heavy rain, a lot less trees and banks. Nothing except not dredging has changed over the past 200 years

I know that however trees growing in a river that floods affects flow and also creates blockages when their are a lot of them removing those would help and the islands that they have created!!

[sirweste]

In reference to the water from storm Desmond:

"...research at the time indicated that given that succession of storms, dredged rivers in Somerset wouldn’t have prevented the floods"

 

Taken from the Chartered Institute of Water and Environmental Management, as @peterboat seems to think EA are lying about the effect of dredging to get out of spending a few quid. 

 

Dredging will help in some instances, but it's not the one stop solution. 

[magpie patrick]

30 minutes ago, sirweste said:

 

 

 

Sorry, here's the link, couldn't think where it was earlier.

 

 

@Dr Bob you're right, the key bit of the question is how much water causes the flood. he images show many many litres spread across land, a bit of dredging isn't going to make much of a dent in that

Dredging alone may not solve the problem, but not dredging where dredging has historically occurred will certainly make it worse

 

Much of the acdemic work is based on whether dredging assists where none had previously occured, rather than on whether it would be a good idea to continue dredging in locations where this dredging has been common practice for tens of decades.

 

In the Somerset Levels, the "bit of dredging" would have prevented flood waters reaching diesel tanks and sewage tanks, and would have left animals able to reach pockets of land above water level - these pockets got submerged. It wouldn't have prevented the floods per se, but it would have stopped them creating a toxic lake

Edited February 24, 2020 by magpie patrick

[tree monkey]

1 hour ago, blackrose said:

 

 

It's the same in my field of expertise (food packaging materials and environmental science). Because it's become a hot topic suddenly everyone is an expert. I'd never dream of telling a teacher or social worker about their job but for some reason they have no problem telling me about something of which they clearly have no knowledge.

 

Try working with trees, everyones an expert

[LadyG]

21 minutes ago, tree monkey said:

Try working with trees, everyones an expert

I 've seen lots of trees, not sure what the fuss is about ............. ?

I must admit being a bit annoyed when my brother ordered some bare-root trees for some land he has aquired [to stop anyone building it has been split into small areas]. I am the agriculturalist, garden, and wildlife person in the family.

Not as annoyed as when father tried to tell me how to sow lettuce! Aparently I have been doing it all wrong.

He plants his lettuce seed,  complained to Suttons Seeds when they did not germinate !

 

Edited February 24, 2020 by LadyG

[magpie patrick]

16 minutes ago, sirweste said:

In reference to the water from storm Desmond:

"...research at the time indicated that given that succession of storms, dredged rivers in Somerset wouldn’t have prevented the floods"

 

Taken from the Chartered Institute of Water and Environmental Management, as @peterboat seems to think EA are lying about the effect of dredging to get out of spending a few quid. 

 

Dredging will help in some instances, but it's not the one stop solution. 

I was part of a team assessing this in 2010 - before the floods. We were looking at navigation but questioned the EA's approach both to dredging and to a barrage (both of which would help navigation on the Parrett, and in our view help with flood risk alleviation) we had pictures of the Parrett twice as wide just thirty years earlier. - the view was clear that they had to find alternatives to dredging because it was expensive and "we're not going to lose Bridgwater" - then in 2014 they nearly DID lose Bridgwater and they had to have a rethink - in 2015 the dredging started up again. 

 

One problem with not dredging is it brings weed growth closer to the surface, which inhibits flow (although the tidal currents on the Parrett meant that wasn't really an issue) - it also leads to increased marginal vegetation and potentially to islands and narrowing of the surface, all of which reduce conveyance.

 

 

[LadyG]

Wind's getting up again, very gusty, it's exhausting.

 

[tree monkey]

1 hour ago, LadyG said:

I 've seen lots of trees, not sure what the fuss is about ............. ?

I must admit being a bit annoyed when my brother ordered some bare-root trees for some land he has aquired [to stop anyone building it has been split into small areas]. I am the agriculturalist, garden, and wildlife person in the family.

Not as annoyed as when father tried to tell me how to sow lettuce! Aparently I have been doing it all wrong.

He plants his lettuce seed,  complained to Suttons Seeds when they did not germinate !

 

Ahhh the planting seed thing gets to me a touch, silly really.

[Naughty Cal]

1 hour ago, peterboat said:

I know that however trees growing in a river that floods affects flow and also creates blockages when their are a lot of them removing those would help and the islands that they have created!!

They have been planting trees in some upland areas to slow down the flow of water heading downstream.

 

In some cases trees can help to prevent flooding!

[Graham Davis]

2 minutes ago, Naughty Cal said:

They have been planting trees in some upland areas to slow down the flow of water heading downstream.

 

In some cases trees can help to prevent flooding!

Where they have been felling around here, due to larch die-back, they have had to dig storage ponds to slow down any run-off.
Calculated that by the time the replanting has grown to an effective level the ponds will have filled up with sediment.

[peterboat]

13 minutes ago, Naughty Cal said:

They have been planting trees in some upland areas to slow down the flow of water heading downstream.

 

In some cases trees can help to prevent flooding!

Its barking here go to meadowhall and the trees are growing in the don right there and of course what keeps on happening there? flooding! Same in Rotherham trees growing in the Don there what happens flooding! the rother where it branches off is silted up to death so what happens upstream from it? flooding! strange how it didnt used to flood when it was all dredged in the olden days when they didnt rely on scientists but common sense, you know like if a gutter is full of silt it cant hold and move as much water as when its clean, but what do we know?

[magpie patrick]

1 hour ago, Naughty Cal said:

They have been planting trees in some upland areas to slow down the flow of water heading downstream.

 

In some cases trees can help to prevent flooding!

Trees on the catchment is one thing

 

Trees in the river is quite another