Bishop Hill Flood prevention
Jan 4, 2016 Climate: WG2 Greens 
I recently chanced upon the website of the Flood Prevention Society, a voluntary organisation that tries to shape public policy on flooding. Their website has a long and detailed report on some of the floods in recent years and, for those with less time on their hands, a snappy "Urban myths about flooding" page. They seem less than impressed with the Environment Agency, and indeed with George Monbiot's ideas about grouse moors and flooding. I reproduce the whole thing here.
1. “Increased flooding is because of more land drainage”.
The opposite is true. During the last Great War and for years after to produce more food and later help the balance of payments, farmers were given a 50% capital grant by Governments to clean ditches, brooks and land drainage. This grant ceased over 30 years ago – so while flooding is on the increase, land drainage is on the decrease.
2. “Modern farming with heavy tractors and machinery causes a plough pan seal (compaction) in the land preventing it soaking up rain, so the rain runs straight into rivers”.
Modern farmers also use subsoilers that break up any plough pan letting air and moisture penetrate up and down – so no change.
3. “Rainfall running off moorland causes urban flooding”.
If it did, as the annual rainfall has not increased, so why are thousands more homes and businesses getting flooded. Moorland has natural boggy areas where the water table can be kept low by drainage channels maintained in good condition. Now with Natural England imposing SSSI control on many moors they have closed the drainage channels, so the water table has lifted leaving no sponge rainwater absorbing affect, therefore the rain now runs off the moors far more quickly. We have the wisdom of ‘hands on experience’ on this subject.
4. “Non porous paving on forecourts, house drives and paths causes rainwater to fill the rivers more quickly”.
Compared to current EA policy of not dredging rivers, the affect of non porous surfaces is negligible – if it has any affect at all, it would be equivalent to shuffling the deck chairs on the Titanic.
5. “Some salmon and trout ‘experts’ say “leave rivers undredged – it is better for the fish”.
This totally incorrect view is confounded in figures published by the EA in the 2009 salmon count which said that the count was the lowest on record. So while rivers are left neglected for 15 years fish are on the decline, likewise water voles are now only found in 6% of their former range say the EA.
6. Another comment by the EA is “If we dredged there is nowhere to put the spoil dredged out”.
The river boards, before EA control, managed to do it – it is very fertile material, most farms have hollows in fields and farmers would be glad of it. It is also good to build up river banks, but it cannot be done by sitting in an office playing with computers creating more flood plains. The Manchester Ship Canal was built in 13 months for Ocean going ships with a minimum water depth of 28’ and bottom width of 120’. The spoil dug out was moved with wheelbarrows and horses and carts – where there is a will there is a way. It was built by private enterprise.
7. Another comment by the EA “We can’t use the spoil dredged out to top up river banks because it is porous”.
We know of river banks built up over 100 years ago by dredged silt with a sandy nature and they have been perfect. A Dutch dredger came up the River Dee 50 years ago depositing the silt by building up its banks. These banks still contain the highest tides of the year despite the river bed now badly being silted up.
8. “Floods caused by farmers not cleaning silt and debris out of ditches”.
It is correct that roadside drains discharge into farm ditches. Most farmers know the importance of ditch dredging but many are frustrated by the fact that where they discharge into a tributary designated main river – under the control of the EA – whose policy of not dredging has caused the silt to build up higher than the discharge points of the farm ditches and land drains.
The worst case of road flooding in our area at times of high rainfall is caused by the EA not dredging a main river tributary. The rain water runs backwards up a farm ditch, runs backwards out of the road drainage grid – floods the road – and then often freezes leaving a sheet of ice on a T junction where cars spin off the road.
9. “Should local councils advise the EA of the need to dredge main rivers in their area”.
They often do, but they get the reply back by word or letter saying that there is no benefit in dredging.
Reader Comments (84)
The Dork does seem to have wandered away from his claims about the nature of the Eden catchment (unsurprisingly since he's never walked the area) to supermarkets in Cork, via a digression on farming in the west of Ireland, and then a walk in the wilds of County Kerry (not all like the Reeks I remember), all of which has lost me long ago. I'm not suie what point(s0 he's trying to make nor which of my points he thinks are factually wrong.
Doesn't Ireland have any interesting web sites where they're considering their problems with the EU directive on drainage?
Budgie
So what change in that percentage (in the areas of present interest) has occurred over the last ten, twenty years to make a change in flooding severity?
Item 6. "Nowhere to put the spoil"
Here the EU is directly responsible. The spoil must be classified as 'hazardous waste' and removed to some 'safe' place at enormous expense to the farmer - the EA won't pay.
Time to leave.
@Capell
The climate / vegetation is very similar on these islands.
If anything the lake district has a slightly shorter growing season for a given altitude but is perhaps protected by a few extra days of snow cover.
Any sort of commercial grazing at 600m ~ in this Atlantic maritime climate is obviously catastrophic for the underlying delicate soil structure.
Think of Lapland, the laps continue to move with their herd.
If they stopped and set up shop in a fixed area then soon life for them would cease to exist.
A good book to start on this subject is
"Mountains and Moorland" by Wh Peasall
It was one of those excellent 1960s Fontana new naturalist books covering the UK at that time.
The supermarket example was not directed at you Capell.
It was in response to the concrete question.
I am being scientific is so far as looking at real world examples.
The Blackpool Cork development is notorious in planning circles down here.
The problems it created has resulted in the implosion of the old trading street.
You are engaged in sophistry.
When not engaged in sophistry I always read from my extensive library on UK farming, landscape management and animal husbandry.
Philip Foster
I keep having this weird sensation of living in some sort of vacuum.
How come the spoil from ditching is hazardous in the UK and not in France? Is it possible that somebody somewhere is interpreting the EU directives more strictly than is necessary? Is it possible that the directive doesn't actually say that spoil is to be treated as hazardous waste at all?
The French do not generally speaking ignore EU directives but they do have a habit of applying them in a way which does not disadvantage them. Which is why they find the Brits occasionally amusing and even more often a bit frustrating in their demands.
"Time to leave" is all very well and a legitimate stance to take but don't for one minute assume that it is some sort of panacea, if only because organisations like the EA will hang on to their little fiefdoms until a future government prises their cold dead fingers off by brute force. I reckon that Brexit will show the UK no benefits at all for at the very least 20 years-- if then. And by that time it will be irrelevant because the EU will have died the death first. Better to stay in and hasten that demise. Most of the people of Europe would thank us for it.
There was a rapid change in agriculture in the Highlands and Islands of Scotland from the 18th century. Sheep replacing crofting leading to a well known quote regarding sheep and men.
From personal observation I suspect that this had a detrimental effect on the remnants of the Caledonian Forest. The commercial forests which replaced the sheep were , for the most part, impenetrable not native pine. What the end result of these changes was in terms of water retention and chemistry was I don't think anyone really knows.
Jan 5, 2016 at 3:49 PM | Unregistered Commenter Capell
If the 10-11% figure is right, then it surely has not changed much since 1950-60, 1-2% and this causes flooding? Every where?
I wrote the above then read the article: http://www.bbc.co.uk/news/uk-18623096
So the figure of 10-11%, reduces to 2.27% when you take out gardens, parks, pitches etc etc. Now about all that massive run-off into the rivers .....
Individual instances of crappy civil engineering are best used to stop crappy civil engineering a second time. The fact that their result happens to be the topic of discussion is, perhaps, of little value.
Capell, Firstly I have not suggested that the built up environment is solely to blame, far from it. Secondly I put a figure to the previously vague notion that (in England at least) the built up area was "negligible". It is far from negligible at 11%. Thirdly I made the specific point that the speed of transfer of surface water (ie flow rate) into the rivers was critical, rather than just volume.
Clearly the most important factor of all is the rainfall itself: how much and how quickly. Both the surface water (man-made) drains, and the river they discharge into, must be capable of transferring the water at a flow rate at least equal to the total input flow rates. As you can see flooding will occur if either or both these conditions are not met.
For any given rainfall that just doesn't cause a flood, a reduction in the removal flow rate (eg by a river silting), or an increase in the flows from built up areas will create a flood problem. Even assuming a 1% population increase translates into only a 0.5% increase in the built environment, it is easy to see that, other factors being equal, a narrow escape could turn into a nasty flood from one year to the next. And the UK is currently increasing its population by about 0.5million every year, or 0.7%, most of whom go to England.
Budgie, I agree with you and made a similar comment on a previous thread. The cause of flooding is not primarily the amount of rainfall but failure to remove it from a flood-prone area before it builds up. Lack of maintenance of water courses, drainage and sewerage systems (and in the case of the latter two, failure to upgrade them to meet increasing demands), as well as development on flood plains and hard landscaping all contribute to the problem.
Rockyspears, You are right, the article goes on to "reduce" the 10.6% and I missed that. However that does not negate the principle that however large/small/contentious the built on area is, it is increasing as the population increases, and is not negligible. Moreover I think the author makes assumptions to reduce the 10.6% that are not warranted, by for example, including the rivers that actually take the run off. His article is not addressing where the rain fall ends up and how quickly it gets there.
Clearly the built environment must have an impact on the rate at which water is discharged into our rivers. All the surface water drainage from roads, buildings etc, which in the wild would fall on open ground and slowly seep away, now gets transferred to the local river almost instantaneously. The area, whether 11% or 3% governs the volume, on average, not the flow rate. As I have said before, it is the speed that the transfer happens which is critical in overwhelming rivers, contributing to flooding.
and still no mention of what nitrogen fertiliser does to soil.
Ask almost any farmer, and I do at every opportunity, "How does nitrogen fert actually work - what does it do to the soil.
Nobody knows.
And in these days of simple science (eg CO2 is a greenhousegas, hence= The World Is Doomed) because it says 'fertiliser' on the bag it comes in, the people using it imagine that by adding it to their land, they are adding 'fertility'
In the case of nitrogen, nothing is further from the truth. Certainly it makes plants grow like triffids on speed but does so by speeding the natural decomposition of organic material within the soil. Acidic waste from that decomposition releases the myriad trace elements from the mineral fraction of the soil.
THAT is why, 30 plus years ago, farmers typically bought/used so-called Nitro-Chalk.
Trademark of ICI, comprising calcium nitrate instead of ammonium nitrate as used now. The calcium supposedly neutralised the acid forming properties of the nitrate.
Now do we see where all the reported cases of Ocean Acidification come from? Typically sheltered coastal waters where folks keep/catch shellfish. The rainwater coming off farmland is much more acidic than it ever used to be and its those farmed shellfish in estuaries that catch it.
Anecdotal from my 250 acre patch.....
It was 'drained' by (Irish) navvies, circa 130 years ago using clay tiles. (The owner at the time had a claypit and brickyard)
I am now in charge of maintaining that drainage system and I find those clay tiles buried under 2, 3 or even 4 feet of solid red clay.
Why On Earth did those guys put those drains under 3feet+ of impermeable clay? Its crazy.
I ask other farmers about this, they dont care, they dont know, its 'just how it is' Now excuse me they say, I've got to go to the farm office and keep the RPA, DEFRA, NE, BCMS etc etc happy
Maybe they didn't put those tiles under all that clay, maybe they put the tiles in black, friable and organic rich peaty soil and over the last century, me, my father and predecessors have quite effectivley removed all the organic fraction. With nitrogen primarily. And ploughs. And overgrazing by sheep.
Where is all that organic material now?
That couldn't be it floating around in the sky, as recorded to multiple decimal places at Mauna Loa, could it?
Surely not, its not like the Keeling Curve shows any sort of annual cycle like you get with farming.....
Jan 5, 2016 at 6:21 PM | Unregistered Commenter Budgie
I do not doubt that it is a contributory factor, but I think 2-2.5% over the time the UK has been inhabited by permanent buildings, IS negligible when talking about "increases" in run-off.
The floods we all see, appear to me, to all be in rural areas*, The Lakes, Cumbria, Yorkshire, Somerset, Scotland as a whole is basically rural. I cannot think that these fractions of % of land cover, changing by fractions of a % over the last 50 years is in anyway way a statistically significant factor.
But it is just my opinion.
Rocky
Jan 5, 2016 at 8:01 PM | Unregistered Commenter Peta in Cumbria
Can't let that one go, sorry. There is no "acidification" as the see is not acidic, but alkali. You may make it "less alkali" but you will never move the oceans to acidic.
If you want Science papers and references for this, here you go: https://rclutz.wordpress.com/2015/06/17/basics-of-ocean-acidification/
Summary
The oceans are buffered by extensive mineral deposits and will never become acidic. Marine life is well-adapted to the fluctuations in pH that occur all the time.
This is another example of climate fear-mongering: It never happened before, it’s not happening now, but it surely will happen if we don’t DO SOMETHING!.
An experiment..
Take a cotton flannel/face-cloth and out it in your (empty) bath, at the far end from the plughole.
Get the largest jug your wife owns from the kitchen, fill with water and pour onto the flannel.
How fast does the water reach the plughole?
Now, replace the flannel with a foot thick bale of towels from the airing cupboard and pour on a bucketful of water.
You don't even need to do the experiment do you?
There it is, how Carlisle and many other places flooded
The single flannel and those towels are exactly the same stuff as is 'soil organic matter', typically cellulose and demonstrate the importance of soil organics and relevance to flooding.
Good organic-rich farmland should have a layer of organics 2 feet thick....
They used to, not any more.
For Rocky..
Slow down a bit ans read what I wrote.
'Ocean Acidification', where it is claimed to be happening (typically in shellfish farms/fisheries) is caused by acidic water coming off farmland. Nitrogen fertiliser does that and was admitted to by manufacturers off the stuff and farmers alike many decades ago
Ocean acidification as claimed to happen by cAGW alarmists (atmospheric CO2 gas dissolving in sea-water is utter utter bollox)
Its a perfect example of that Simple Science I mentioned before. nobody does any serious thinking any more.
Something that should be considered in relation to the floods in Cumbria is that the area was a major mining district for lead, zinc and fluorspar throughout the 18th and 19th centuries, and only finally ceased in the '60s.
Careful maintenance of the watercourses was absolutely essential, not only to ensure the mines were kept drained, but also because water was the prime source of motive power at the mines in the form of waterwheels, hydraulic engines and turbines well into the 20th century.
Once mining activity declined and then ceased, there was no pressure from mining companies on local or national authorities to adequately maintain the watercourses.
Jan 5, 2016 at 8:29 PM | Unregistered Commenter Peta in Cumbria
My apologies, but the language you used is the same as the AGW crowd, my mistake.
"Something that should be considered in relation to the floods in Cumbria is that the area was a major mining district for lead, zinc and fluorspar throughout the 18th and 19th centuries, and only finally ceased in the '60s."
My 81 year old father started his working life as a Lakeland shepherd and knows the area around Glenridding like the back of his hand ( I was born just the other side of Patterdale). I watched news coverage of the flooding with him and he immediately mentioned the closure of the local lead and slate mines and subsequent lack of watercourse management as the only credible reason for that area flooding.
@Mike Jackson -
"How come the spoil from ditching is hazardous in the UK and not in France? Is it possible that somebody somewhere is interpreting the EU directives more strictly than is necessary? Is it possible that the directive doesn't actually say that spoil is to be treated as hazardous waste at all?"
Richard North claims that there is a distinction between "De-Silting" and "Dredging". The former IS permitted, and the spoil can be deposited on the river banks, whereas Dredging is interpreted as more substantial work which removes the original bed material - it is this which is classed as "hazardous". Seems to be a typical UK case of a (not so) civil servant deliberately interpreting EU rules to pursue Agenda 21. If what RN says is correct, there would appear to be no reason why all the rivers and watercourses which have been neglected for the past 20 years could be cleared of debris, and restored to proper function. But that would take someone with the balls to face up to the
bastardsSir Humphreys who really run this country...Mike Jackson;
I suspect Dave Ward is correct "Seems to be a typical UK case of a (not so) civil servant deliberately interpreting EU rules to pursue Agenda 21. " and save the EA a lot of dosh and effort. However, in the case of Cumbria, if the silt has been contaminated with mine effluent and/or old processing tailings it will be contaminated with lead, zinc, and cadmium, and is, by definition, hazardous waste.
However, if it can be shown that the EA and/or local authorities were responsible for allowing the floodwaters to be contaminated with mine effluent/tailings through negligence, they would be legally responsible to clear it up and carry out preventative work to stop it happening again.
Here's a video of a Scottish castle teetering (their term) on the banks of a flooded river that our local weather channel posted with nary a word of climate change having caused it . . . perhaps there were other reasons.
Peta,
If all that organic material has gone then explain why we have sunken lanes (round here there are many cases where walls 1 metre high are now buttressed on the field side by organic detritus soil (i.e. shit) one metre high) rather than walls high and dry, teetering on a remnant of ancient organic material?
I thought we did understand how nitrogen worked on plants? Isn't that why we're trying to develop strains of common cereal crops that would increase capture of nitrogen in their root systems?
Surely the vast amounts of CO2 that are dissolved in the oceans in H2CO3 form do contribute to the acidic portion of our alkali oceans? And the analysis of Murray Salby describing the exchange of CO2 in the oceans with that in the atmosphere seems correct?
As to your drains, we either assume the navvies and the farmers of old were thick (doubtful) or the observation needs a little more thought?
Budgie and Rocky
the position that urbanisation will increase the flooding risk seems right. And I further agree that it will not be a significant cause. That would be especially so in the case of the northern Eden catchment where the only villages of any significance are Appleby and Kirby Stephen.
Everyone:
Eyes down at 2:30 pm for the Environment, Food and Rural Affairs Committee with Dilley as a witness.
Mike J
"Is it possible that somebody somewhere is interpreting the EU directives more strictly than is necessary?"
Do bears etc..?
IIRC, the first action of the EA on reading the supposed directive on the hazards of silt was to destroy all the dredging equipment! Why are government departments never run by people who know anything about the subject at hand..?
I believe there is a UK House of Commons Select Committee meeting this afternoon. which will be available on Parliament TV.
It will be interesting to see if Sir Philip Dilley or Sir James Bevan try to attribute the recent floods to "unprecedented" rainfall in November and December 2015. Of particular interest to pop-corn consumers like me is to see if, assuming that they blame the weather, they try to cite Met Office figures. The figures for 2015 were published last night, but there seem to be two editions, which I designate here the Hadley edition and the Weather edition.
I haven't had time to study these in detail. I have simply added together the figures for November and December together for each year from 1910 including 2015. It appears at first glance that the Weather Edition for this combined monthly total consistently runs about 50 mm wetter than the Hadley edition, until 2015, whereupon the 50 mm suddenly becomes 160 mm, an adjustment which is unprecedented, though approached (145mm) in 1929. The 50mm I am not concerned about: I suspect it is different ways of estimating the overall figures based on different weights given to the rain gauges (and perhaps rainfall radar). However, I am concerned that the "hydrostick" that results from this adjustments is a mere umbrella under which the EA will shelter for a month or two, until the fully Quality Controlled Hadley figures come out later in the year, by which time the storm of press attention will have moved elsewhere, such as unprecedented heatwaves. I expect the hydrostick will then be quietly removed ("QA amendments, routine, nothing to see here"), while no-one is watching, and put into store ready for the next floods.
Ditch blocking reduces Exmoor storm flows by >70% - apparently
According to the ONS: "Since 1964 the population of the UK has grown by over 10 million people (18.7%). About half of this growth has occurred since 2001." That is the equivalent of four Birminghams in only 15 years - a massive increase in the built area in a short time. There are around 8 million people in the UK (most in England) who were not born here - that requires a city the size of London over and above what was needed before mass immigration.
For historical reasons our towns and cities are often built on, or near, rivers. Even one field built on as a housing estate in a village near a river could make the difference between a near miss one year, to flooding the next for the same weather conditions. It takes only a minor change for a dangerously close call one year to become an actual flood the next. A 9% increase in population in only 15 years is far from minor.
I believe the 2011 NEA estimate of 10.6% built area for England is useful: gardens, parks, sports grounds etc, in our cities, all have hard standing or compacted ground that contribute to rapid run off as well as buildings, roads and other infrastructure. And of course rivers are the main sink to which surface water is directed. These cannot be dismissed merely because some features appear superficially bucolic. However the absolute size of the built up area is not really the point, it is the increase in area over a short time.
Whilst there are many factors that contribute to flooding, including specifically local ones, there are only two that have changed significantly in the last decade or two. One is the lack of dredging and the second is the increase in size of the built environment with its concomitant rapid discharge (ie high flow rate) of surface water into our rivers, both of which I have highlighted.
@budgie:
The important point to remember about the built environment is that the majority of rain is piped off it and directly into the rivers via the surface water drainage system (this is separate from the sewage system, though there are some connections usually by weirs)
That certainly is NOT the case in even suburbia, as the building regs mandate soakaways - essentially every dwelling needs a way to absorb rainfall into some sort of subsoil containment, or a dry pond that fills up.
.
"To try and ensure water is dispersed into the ground evenly and quickly you must consider the
use of a soakaway in all cases.
You must use a soakaway if design criteria can be met. Discharging stormwater into a drain will
only be allowed if soakaways or other infiltration methods are not suitable."
so storm drains are very much deprecated, and only to be used if there is no other means to disperse water from a residential or commercial building
Peta in Cumbria,
I'm fascinated by your soil theories. We've been farming a bit of Hampshire for 55 years, and it varies from chalky loam to heavy clay - and they have always been chalky loam and heavy clay. The reason you put drains under clay (as we did extensively in the mid 1960s) is that heavy clay is by its very nature less prone to drain itself - you wouldn't put in drains under friable organic-rich soil because that drains easily on its own. I've dug out my copy of 'Soil Management' by Davies. Eagle and Finney (a vital textbook for us Agricultural Engineers), and there are four situations where drainage is required (Chapter 5): Lowland Basins, Springs sites, Soil Pans and Clayland Areas. No mention of organic rich peaty soil. I would also suggest that the fact that previous occupiers had a brickworks suggests that the clay must have always been there.
I don't think anything can change one sort of soil into another, although it's true that some action results in depletion of organic matter (OM). Ploughing does by exposing OM that then decomposes, but sheep grazing can't affect anything but the top couple of inches, and nitrogen (I assume you mean modern inorganic nitrogen) doesn't - we know that straw breakdown in the soil profile can use up a lot of nitrogen, but that's from its bulky 'harvest' form to soil OM. Crop growth is above and below ground, so nitrogen boosted crops will add organic matter underground. Inorganic nitrogen is a recently recent invention, too.
Hope this makes sense. I'm very sorry that other farmers can't be bothered to discuss this with you!
Dave Ward Jan 5, 2016 at 10:21 PM
If there is a distinction between 'de-silting' and 'dredging' with dredging producing hazardous waste how come they sell the sand and gravel that is dredged out of the river/empty lake here in my area of France?
I can only assume the distinction is because the Whitehall wallies have very liberally gold plated the directive as they always do to the joy of the green blob.
Ivan;
More likely to have been a case of EA wallies using Brussels gobbledygook to consign the determination of what is, or isn't hazardous waste to the circular filing-cabinet and saving themselves the effort.
@Phil-Foster
Dredged material is exempt from the hazardous waste regulations, within large parameters. There are few reasons for not depositing the spoil over nearby fields or the riverbanks.
https://www.gov.uk/guidance/waste-exemptions-disposing-of-waste
"D1: key conditions
The waste must be deposited as close as possible to where it was dredged from.
The waste must be deposited either:
on the bank of the waters from where it was dredged
or on land next to the water it was dredged from (the dredgings must be removed from the waterway and deposited mechanically in one operation)
UAV company offers to map UK to prevent future flooding
Unmanned air vehicle provider Strat Aero has offered the UK government use of its aerial 3D mapping services to help inform flood prevention studies.
[ ... ]
“This will provide an excellent foundation for the formulation of a pre-emptive strategy to improve the country’s flood defences, and in the process help prevent further flood damage and suffering occurring in the future.”
The letter was sent the week starting 11 January, but Strat Aero had not received a response from Stewart at the time of going to press.
https://www.flightglobal.com/news/articles/uav-company-offers-to-map-uk-to-prevent-future-flood-421124/