UKBouldering.com

180k cragx Mill Bridge (Read 65546 times)

Dingdong

Offline
  • ****
  • forum abuser
  • Posts: 597
  • Karma: +44/-9
#150 Re: 180k cragx Mill Bridge
February 06, 2024, 03:01:26 pm
Shilling? Get a grip

“A shill, also called a plant or a stooge, is a person who publicly helps or gives credibility to a person or organization without disclosing that they have a close relationship with said person or organization.”

Literally what he’s done here.

Will Hunt

Offline
  • *****
  • forum hero
  • Superworm is super-long
  • Posts: 8177
  • Karma: +661/-121
    • Unknown Stones
#151 Re: 180k cragx Mill Bridge
February 06, 2024, 03:15:59 pm
Also Water UKs members are comprised of the water companies, not exactly trustworthy source either.

Water UK is a trade association for the water industry so it would be very odd if it wasn't comprised of water companies. A bit like the BMC is comprised of climbers and hillwalkers.

Oh and funnily enough Ruth Kelly who chairs Water UK got a job working at policy exchange the year before starting her role at Water UK, a right wing think tank aka lobby group…

That's interesting, I didn't know that. I'm still waiting on some evidence that Water UK has lobbied government to "dismantle regulation".


I can hardly say that I'm completely unbiased. We are all biased in some way, but in responding on this thread I have attempted to be as balanced as I can. Certain things in my posts are clearly my personal opinion ("the Environment Act is flawed") which isn't necessarily the opinion of any water company, though to say a piece of legislation is flawed is hardly earth-shattering as almost all legislation is flawed in some way. However, you should be able to see in my posts that a lot of what I've said is just statement of fact, drawing on an educational background in river ecology and over 10 years working in environmental regulation and river modelling. You can use your own faculties of critical thinking to see which is personal opinion and which is simple fact. I've provided you with lots of links to non-water company sources of data and information (the EA, the government, the Chair of the Aire Rivers Trust) so you can form your own view.

One thing I would say (and you can call me biased if you like because this is obviously a personal opinion) is that the general level of science reporting in the press has been pretty poor and I believe the ecological impact of storm overflows isn't well understood by the public. If you're interested in finding out what is to come in the future for UK water industry regulation you can google things like the Environment Act and the storm overflows discharges reduction plan. If you're interested in how the impact of storm overflows on river ecology has been assessed and improved over the last few decades you can google "Urban Pollution Management investigations" and you could have a look at the Fundamental Intermittent Standards described here (page 66):
https://www.wfduk.org/sites/default/files/Media/Environmental%20standards/UKTAG%20Environmental%20Standards%20Phase%203%20Final%20Report%2004112013.pdf.


Shill?  :lol:
You might as well say that Paul B and Fultonius are shilling for Big Bridge.

spidermonkey09

Offline
  • *****
  • forum hero
  • Posts: 3117
  • Karma: +173/-4
#152 Re: 180k cragx Mill Bridge
February 06, 2024, 03:16:46 pm
If you give this blog a read rather than dismissing it as the work of some random bloke you might learn something.

https://geoffroberts.me/river-quality-what-has-gone-wrong/

I didn't know, for example, that the methodology used to measure water cleanliness was changed.

Quote
The published data shows that every single river in the country fails the chemical standards set for them. And it’s not that which makes me so angry. What makes me angry is that the failures are down to the EA changing their methodology ...

Our rivers may not have actually deteriorated, they just appear to have done so because of this quirk of the system! But we don’t actually know because we are being asked to compare apples with oranges.

mark20

Offline
  • ****
  • junky
  • Posts: 911
  • Karma: +132/-0
#153 Re: 180k cragx Mill Bridge
February 06, 2024, 03:27:16 pm
I've wondered if there is much evidence to say that UK rivers are considerably more polluted than say 40 years ago, or just that media coverage has increased over the last couple of years (and that the pollution targets themselves are considerably more stringent). Would be interested if Will/Carlos has anything on that?

Interestingly there was an piece on the radio the other day about how surface run off from roads was one of the biggest polluters (after sewage, and agricultural runoff) and gone under the radar for a long time. Oils, microplastics from tyres etc.
I just had a quick look at my local Water company online and the first news item on their website is their achievement in relieving their sewer network (after much pressure by campaigners etc no doubt) by building a new surface water drain that takes highways drainage... straight into the river!
 
"the construction of a new surface water sewer running the full length of the village to remove highways drainage and surface water from some properties from the combined sewer. The surface water will be discharged straight to the watercourse, significantly reducing flows through the combined sewer, cutting discharges of wastewater to the [river]"

Tony S

  • Guest
#154 Re: 180k cragx Mill Bridge
February 06, 2024, 03:38:18 pm
I've wondered if there is much evidence to say that UK rivers are considerably more polluted than say 40 years ago…

No. It’s broadly the opposite, as Pete’s earlier post highlighted (specifically relating to rivers). When it comes to coastal waters, it’s an even better picture, see various EU environmental reports  on the topic.

But quality has many different metrics, they won’t all go in the same direction.

We should also be mindful that we should, to some degree, expect/wish for things to get better with time: that’s generally called progress.

Tony S

  • Guest
#155 Re: 180k cragx Mill Bridge
February 06, 2024, 03:40:50 pm
Since we’ve made it to yet aaaanother page, especially if you don’t wanna read this thread any further

Please consider helping to fund a replacement bridge at Cress-brook Mill by donating to the PDNP Foundation's fundraiser for this at: https://shorturl.at/cesz8

You can also donate by:

Bank transfer to ‘Peak District National Park Foundation’, sort code 20-10-71, account 63364895, Barclays Bank, quoting Cress-brook Bridge
Cheque made payable to Peak District National Park  Foundation with your contact details and marked Cress-brook Bridge to Aldern House, Baslow Road, Bakewell, Derbyshire, DE45 1AE

However, if you want to add gift aid (giving them an additional 25%), you’ll need to email them for a gift aid form to complete if you use bank transfer or cheque.

Nice one to all those people who have already donated.

Dingdong

Offline
  • ****
  • forum abuser
  • Posts: 597
  • Karma: +44/-9
#156 Re: 180k cragx Mill Bridge
February 06, 2024, 03:51:27 pm
I've wondered if there is much evidence to say that UK rivers are considerably more polluted than say 40 years ago…

No. It’s broadly the opposite, as Pete’s earlier post highlighted (specifically relating to rivers). When it comes to coastal waters, it’s an even better picture, see various EU environmental reports  on the topic.

But quality has many different metrics, they won’t all go in the same direction.

We should also be mindful that we should, to some degree, expect/wish for things to get better with time: that’s generally called progress.

I wasn’t talking about since the industrial revolution or even 40 years. I’m talking timeframes of 5-10 years.

petejh

Offline
  • *****
  • forum hero
  • Posts: 5884
  • Karma: +639/-36
#157 Re: 180k cragx Mill Bridge
February 06, 2024, 03:59:53 pm
Facts then please. To back up your claim. Show us data that levels of pollutants have increased on average in UK watercourses and coast in the past '5-10 years'. Which pollutants, which rivers, and which areas of coastline. Not Monbiot articles preaching to his crowd, clever and well-intentioned as he no doubt is.

Also consider whether '5-10 years' is a particularly significant timescale either way (improvement or degradation) in the context of what you're discussing.   


Dingdong

Offline
  • ****
  • forum abuser
  • Posts: 597
  • Karma: +44/-9
#159 Re: 180k cragx Mill Bridge
February 06, 2024, 04:09:02 pm
Facts then please. To back up your claim. Show us data that levels of pollutants have increased on average in UK watercourses and coast in the past '5-10 years'. Which pollutants, which rivers, and which areas of coastline. Not Monbiot articles preaching to his crowd, clever and well-intentioned as he no doubt is.

Also consider whether '5-10 years' is a particularly significant timescale either way (improvement or degradation) in the context of what you're discussing.

Nah I’m good

Oldmanmatt

Offline
  • *****
  • forum hero
  • At this rate, I probably won’t last the week.
  • Posts: 7341
  • Karma: +385/-17
  • Largely broken. Obsolete spares and scrap only.
    • The Boulder Bunker climbing centre
#160 Re: 180k cragx Mill Bridge
February 06, 2024, 05:25:13 pm
Facts then please. To back up your claim. Show us data that levels of pollutants have increased on average in UK watercourses and coast in the past '5-10 years'. Which pollutants, which rivers, and which areas of coastline. Not Monbiot articles preaching to his crowd, clever and well-intentioned as he no doubt is.

Also consider whether '5-10 years' is a particularly significant timescale either way (improvement or degradation) in the context of what you're discussing.

How could it be a reasonable timeframe. A couple of bad flooding seasons, consecutively would screw up that.

tomtom

Offline
  • *****
  • forum hero
  • Posts: 20328
  • Karma: +649/-11
#161 Re: 180k cragx Mill Bridge
February 06, 2024, 05:38:18 pm
2022 report from the Parliament Environmental Audit Committee

https://publications.parliament.uk/pa/cm5802/cmselect/cmenvaud/74/report.html

The summary below isn't my cup of tea style wise - but the report contains some useful tables/data findings if you want to have a look for yourself.

Quote
Summary
Getting a complete overview of the health of our rivers and the pollution affecting them is hampered by outdated, underfunded and inadequate monitoring regimes. It is clear, however, that rivers in England are in a mess. A ‘chemical cocktail’ of sewage, agricultural waste, and plastic is polluting the waters of many of the country’s rivers. Water companies appear to be dumping untreated or partially treated sewage in rivers on a regular basis, often breaching the terms of permits that on paper only allow them to do this in exceptional circumstances. Farm slurry and fertiliser run off is choking rivers with damaging algal blooms. Single use plastic sanitary products—often coated with chemicals that can harm aquatic life—are clogging up drains and sewage works and creating ‘wet wipe reefs’ in rivers. Revolting ‘fatbergs’ as big as blue whales are being removed from sewers, costing companies and their customers in the region of £100 million a year. Not a single river in England has received a clean bill of health for chemical contamination. Disturbing evidence suggests they are becoming breeding grounds for antimicrobial resistance.

Cleaning up our rivers is important for public health and vital to protect wildlife. The world is experiencing an extinction crisis and freshwater eco-systems are on the frontline. The build-up of excess nutrients like phosphorus and nitrogen from animal waste and sewage is reducing oxygen levels in rivers and in severe cases can cause fish kills. Along with the stresses of plastic and synthetic chemical pollution and climate change this is creating multiple pressures undermining the health and resilience of these key ecosystems. It should ring alarm bells that wild Salmon are classed as ‘at risk’ or ‘probably at risk’ in almost every river they traverse. Rivers where we know important species such as the North Atlantic Salmon are in danger must be protected from pollution as a priority.

The sewerage system is overloaded and unable to cope with the increasing pressures of housing development, the impact of heavier rainfall, and a profusion of plastic and other non-biodegradable waste clogging up the system. Successive governments, water companies and regulators have grown complacent and seem resigned to maintaining pre-Victorian practices of dumping sewage in rivers. There has been investment in the network since privatisation, but underlying problems have not been resolved and capital investment has not kept pace with housing and other development pressures on the drainage and treatment network. Biodiversity has not been priced adequately into economic decision making. The water regulator Ofwat has hitherto focused on security of water supply and on keeping bills down with insufficient emphasis on facilitating the investment necessary to ensure that the sewerage system in England is fit for the 21st century.

A step change in regulatory action, water company investment, and cross-catchment collaboration with farmers and drainage authorities is urgently required to restore rivers to good ecological health, protect biodiversity and adapt to a changing climate. Investment must be accelerated so that damaging discharges from water treatment assets including storm overflows cease and that any spills occur only in genuinely exceptional circumstances. Financial penalties for pollution incidents and misreporting must be set at a level that puts the issue on the agenda in water company board rooms. Ofwat should examine the powers it may have to limit the payment of bonuses to water company executives while companies persistently breach their permits.

Intensive livestock and poultry farming is putting enormous pressure on particular catchments, such as the one feeding the River Wye. As many as twenty million chickens are being reared there and their waste may be raising the river’s phosphorus levels. Planning permission seems to be granted for individual units without any cumulative assessment being made of the overall impact of all the intensive farms in the area. Each catchment should have a nutrient budget calculated. Pollution from all sources in the catchment must then be progressively reduced or mitigated until it does not exceed the capacity of the river to handle the nutrients. New poultry farms should not be granted planning permission in catchments exceeding their nutrient budgets.

National Highways must accelerate its efforts to eliminate toxic chemical and plastic pollution from the most polluting outfalls on the Strategic Roads Network by 2030 in line with the Government’s commitments to halt species decline. We expect to see far more assertive regulation and enforcement from Ofwat and the Environment Agency to restore our rivers to their natural glory.

My view: Establishing a time line of how quality has changed is difficult, as there has been a widespread decline in monitoring and you need a long time series of the relevant (an issue itself) metrics for WQ at multiple (hundreds really) of locations. WQ is also highly spatially and temporally variable - for example a pollution incident might only last an hour and be swept away in a matter of hours but have a widespread long lasting impact on the river. If you only sample the river once a day/week/month/year (etc..) then you will likely miss it. Continuous monitoring is expensive and will only pick up certain pollutants or indicators of WQ. Therefore its very difficult to answer Petes question - as 'facts' are in short supply - have been taken sporadically in different locations mostly over periods less than 40 years. However, what data we have has declined considerably in the last 5 years with widespread cuts to the EA's monitoring budget. 

Speaking qualitatively,  as someone who doesn't work on WQ but works with plenty of people who do, WQ is probably on average better than it was 40 years ago. But considerably worse than it was 10 years ago. In the mid-late 90's and onwards there was considerable effort and expenditure to improve river water quality to meet the EU water framework directive. Sewage discharges into rivers and the the sea were dramatically reduced (almost eliminated) over this period to a zenith somewhere around 2010-2015. Since then its all sadly got worse.


Dolly

Offline
  • *****
  • forum hero
  • Posts: 2034
  • Karma: +84/-0
#162 Re: 180k cragx Mill Bridge
February 06, 2024, 11:30:50 pm
I wonder if I can work out a possible correlation here. Were the Tories IC by any chance?


Will Hunt

Offline
  • *****
  • forum hero
  • Superworm is super-long
  • Posts: 8177
  • Karma: +661/-121
    • Unknown Stones
#163 Re: 180k cragx Mill Bridge
February 07, 2024, 11:28:30 am
for example a pollution incident might only last an hour and be swept away in a matter of hours but have a widespread long lasting impact on the river. If you only sample the river once a day/week/month/year (etc..) then you will likely miss it.

Yep, this is a very significant limitation of the EA's spot sampling regime for water chemistry. If you're only going out once a year or even every three years then it's unlikely that you'd catch an intermittent problem. That's why it's so important to look at the ecological indicators (the fish and invertebrates classifications in the Catchment Data Explorer I linked to earlier). An intermittent pollution problem will leave a lasting impression on the ecology of the river. Macroinvertebrates are particularly useful as they have varying tolerances to pollution. The EA will do a kick sample in the river and count up how many of each species they find. There's a metric that then allows you to classify the health of the river (the WHPT: https://wfduk.org/sites/default/files/River%20Invertebrates%20WHPT%20UKTAG%20Method%20Statement%20-%20updated%20May%202021.pdf). The TL;DR is that if you're finding only pollution-tolerant organisms like worms, leeches, and water hoglouse (among others) then you've got a pollution problem, even if your chemistry sampling on the same day seems OK. If you're finding healthy populations of stonefly and mayfly larvae, which are very intolerant of pollution, then it means things are looking good.

As an excuse to post a photo of my kid again, here we are during lockdown investigating a local watercourse using equipment that I had left over from when I did some voluntary sampling for the Rivers Trust.





I'm a bit rusty so forgive me if I get this wrong but I'm certain that's a stonefly larva. You can just about see some little fronds sticking out from its side. Those are its gills. Pretty cool!

WQ is probably on average better than it was 40 years ago. But considerably worse than it was 10 years ago. In the mid-late 90's and onwards there was considerable effort and expenditure to improve river water quality to meet the EU water framework directive. Sewage discharges into rivers and the the sea were dramatically reduced (almost eliminated) over this period to a zenith somewhere around 2010-2015. Since then its all sadly got worse.

I'm intrigued by this, Tom, because it doesn't chime with my understanding. The WFD came into force at the very end of 2000, superseding things like the Freshwater Fish Directive. This brought about programmes of investment to reduce the concentration of ammonia, BOD, and more latterly phosphorous discharged from wastewater treatment works, which helps to continue the trends in the graphs linked to by Jonathan upthread. Caveat: its possible your colleagues are referring to a worsening of pollution from emerging pollutants (such as pesticides, pharmaceuticals etc). This isn't my area so I can't really offer too much information with confidence - I'm mainly talking about things like ammonia and BOD.
The WFD also drove programmes of investment in water quality investigations - these are the UPM studies that I mentioned earlier. The aim of these investigations is to find storm overflows that are causing environmental harm and develop capital solutions that will eliminate that harm. What there hasn't ever been before is a push to reduce storm discharges across the whole country even where those storm discharges are not causing environmental harm - there hasn't been the legislation, funding, or the will from government (of all parties) or regulators to do it, so I don't think it can be true to say that storm discharges were almost eliminated.

This is where the paradigm shift comes in with the Environment Act. Whereas the aim of the WFD was to eliminate environmental harm, the Environment Act (among other things) requires companies to reduce each storm overflow to an average of 10 spills per year (regardless of whether the overflow is causing environmental harm) AND if at 10 spills you'd still cause environmental harm then you must go further to ensure there is no harm. It's difficult to overstate how massive this is. It's the beginning of a mind-boggling amount of work to completely overhaul urban drainage requiring £billions of investment.

To try and aid people's understanding of why this is such a big challenge, this is a photo of a storm overflow chamber (taken by some silly sod urban explorer. Please do not venture into the sewer network. It is a phenomenally dangerous place).


What you see there is sewage running along a central channel. This is a combined sewer so takes effluent from homes and businesses but also runoff from streets and other impermeable surfaces. When it rains heavily and the system reaches capacity, flow will back up into this chamber, the level will rise, and flow will pass through the two circular tubes on either side. These are mechanically-cleaned screens which prevent solid matter larger than 6mm in 2 dimensions from escaping into the environment (basically a big sieve that scrapes itself clean). The little blue thing you can see above the channel is the ultrasonic level sensor which records the flow level in the chamber for Event Duration Monitoring. It's the same as your bathroom sink: you have an inlet and an outlet, and if the inlet beats the outlet then the water level in the sink will rise until it find its way out of the high-level relief slot. The alternative is water all over your bathroom floor or, in the case of sewers, sewage backing up out of your toilet and onto the bathroom floor, or sewage surcharging out of manholes and running down the road.

In order to reduce the number of times this spills you have a few options and to meet the requirements of the Environment Act the water industry will need to deploy a range of these on a massive scale. The traditional way is to build a neighbouring tank into which storm sewage can pass. Once this tank is filled it might still spill to the environment, but if you've sized it properly then you can dramatically reduce the number of discharges. The other thing you can do (and the reality is that to meet the requirements of the Environment Act we'll need concrete tanks AND these "blue-green" solutions) is to separate out the rainfall from the sewer. To avoid flooding you still need to attenuate that rainfall and you'd do this by reducing the impermeable area in the catchment using Sustainable Drainage Systems (SuDS. Loads of info out there about these). We live in towns and cities which have sprawling impermeable areas and not a lot of room to build whopping great storm tanks and SuDs, and climate change will drive more intense rainfall, so it's going to be quite challenging!


stone

Online
  • ****
  • junky
  • Posts: 924
  • Karma: +55/-5
#165 Re: 180k cragx Mill Bridge
February 07, 2024, 12:03:25 pm
I think Mark20 once said that it might help if all buildings had a waterbutt with a trickle out-outflow so that rain on roofs didn't all go into the sewers at once. Instead it would trickle in over a much more extended period.

Will Hunt

Offline
  • *****
  • forum hero
  • Superworm is super-long
  • Posts: 8177
  • Karma: +661/-121
    • Unknown Stones
#166 Re: 180k cragx Mill Bridge
February 07, 2024, 12:19:30 pm
Will, re your last paragraph, is that what this is referring to:

https://www.unitedutilities.com/corporate/newsroom/latest-news/united-utilities-invite-ramsbottom-residents-to-find-out-about-irwell-improvement-project/#:~:text=The%20new%20storm%20tank%20will,quality%20of%20the%20River%20Irwell.

Exactly. 3500m3. The cost will be somewhere in the region of £7m.

This isn't a great picture but the only one I can find that shows how big these things can get. This is one of the storm tanks on the east coast when it was about a third dug (total depth about 30m).



I think Mark20 once said that it might help if all buildings had a waterbutt with a trickle out-outflow so that rain on roofs didn't all go into the sewers at once. Instead it would trickle in over a much more extended period.

Smart water butts are a nice thing and can definitely go some way to helping, but we're talking about an engineering problem that dwarfs what you can achieve with them alone.

I recently heard a presentation from someone in Southern Water where they'd given out a load of smart water butts in a particular catchment. The butts retain water in their bottom half that people can then use on their garden; the top half fills up then drains down slowly to make room for more water next time it rains. They had to go out after a few months and fit anti-tamper devices to stop people removing the separation between the two halves (so that they would have a permanently full water butt for their garden, offering no attenuation while full).

teestub

Offline
  • *****
  • forum hero
  • Posts: 2796
  • Karma: +178/-4
  • Cyber Wanker
#167 Re: 180k cragx Mill Bridge
February 07, 2024, 12:47:45 pm
To avoid flooding you still need to attenuate that rainfall and you'd do this by reducing the impermeable area in the catchment using Sustainable Drainage Systems (SuDS. Loads of info out there about these). We live in towns and cities which have sprawling impermeable areas and not a lot of room to build whopping great storm tanks and SuDs, and climate change will drive more intense rainfall, so it's going to be quite challenging!

Or in the case of Ilkley (and I'm sure other places) reroute the culverts bringing streams off the moor from entering the WTW!


Will Hunt

Offline
  • *****
  • forum hero
  • Superworm is super-long
  • Posts: 8177
  • Karma: +661/-121
    • Unknown Stones
#168 Re: 180k cragx Mill Bridge
February 07, 2024, 01:10:59 pm
Can't really comment on that specifically as I don't know enough about it but, yes, that sort of thing is one intervention among many that is necessary to meet the new requirements.
Stuff like this, for example:
https://www.yorkshirewater.com/news-media/news-articles/2023/second-tunnel-completed-on-new-ilkley-sewer/

ali k

Offline
  • ****
  • junky
  • Posts: 967
  • Karma: +40/-1
#169 Re: 180k cragx Mill Bridge
February 07, 2024, 04:33:39 pm
Will - I haven't read the whole thread so sorry if this is a repeat, but just thinking about the combined sewers and storm surges/discharges. Is there any justification/explanation for sewage being dumped through these in low flow times? Or is it literally just a cost saving exercise to avoid having to treat it? I gather people have cross-referenced rainfall data with discharges and found this to be the case on a huge number of occasions.

[not meant in an antagonistic way - just trying to understand]

Will Hunt

Offline
  • *****
  • forum hero
  • Superworm is super-long
  • Posts: 8177
  • Karma: +661/-121
    • Unknown Stones
#170 Re: 180k cragx Mill Bridge
February 07, 2024, 05:07:37 pm
Will - I haven't read the whole thread so sorry if this is a repeat, but just thinking about the combined sewers and storm surges/discharges. Is there any justification/explanation for sewage being dumped through these in low flow times? Or is it literally just a cost saving exercise to avoid having to treat it? I gather people have cross-referenced rainfall data with discharges and found this to be the case on a huge number of occasions.

[not meant in an antagonistic way - just trying to understand]

Storm overflows definitely shouldn't be operating in dry weather. If they are then it could be because, for instance, there's a blockage in the network that's causing flow to back up (normally due to nappies, wipes, fats/oils/greases, Christmas trees [really]) that people have put down the sewer. In this event the company should be able to detect that by looking at their EDM data, but if you see something like this then definitely report it to the company so they can get out and fix it ASAP. If you're concerned about environmental impact then you can also report to the Environment Agency (info here: https://www.gov.uk/report-an-environmental-incident).

Worth bearing in mind that not all pipes that go into rivers are storm overflows and it's not always easy to tell by sight if something is discharging storm sewage or just surface water (which may still discharge in dry weather due to groundwater infiltration of the pipes), but if in any doubt then get it reported.

ali k

Offline
  • ****
  • junky
  • Posts: 967
  • Karma: +40/-1
#171 Re: 180k cragx Mill Bridge
February 07, 2024, 05:51:10 pm
As I understood it they were cross-referencing rainfall data with the water companies’ own discharge data rather than just observing pipes, but I could be wrong on that.

teestub

Offline
  • *****
  • forum hero
  • Posts: 2796
  • Karma: +178/-4
  • Cyber Wanker
#172 Re: 180k cragx Mill Bridge
February 07, 2024, 05:57:25 pm

Will Hunt

Offline
  • *****
  • forum hero
  • Superworm is super-long
  • Posts: 8177
  • Karma: +661/-121
    • Unknown Stones
#173 Re: 180k cragx Mill Bridge
February 07, 2024, 06:17:10 pm
Hmmm. Difficult to comment without understanding the analysis and how it's been done.

A likely explanation is that there's a limited network of rain gauges (you can find EA rain gauges here: https://environment.data.gov.uk/hydrology/explore) to draw data from. If you click that link and look at the map it looks like there's loads of them but rainfall is actually far more spatially variable than you might think. Even in one small or medium sized sewer catchment you can have really intense rainfall in one area and light/no rainfall in another. So your rain gauges at Chesterton, Etton, and (wait for it) Dog-in-a-Doublet might show that it isn't raining, but that doesn't mean that it isn't battering down in Peterborough town centre and causing storm discharges.

The picture gets even more complicated in large, sprawling urban sewer catchments with a high degree of hydrological complexity, where what is happening in one or more parts of the network can combine to have a knock-on affect on another part of the catchment.

But as I said, not really possible to comment with certainty without getting into the detail and understanding where the data has come from and how it's been analysed.

ali k

Offline
  • ****
  • junky
  • Posts: 967
  • Karma: +40/-1
#174 Re: 180k cragx Mill Bridge
February 07, 2024, 06:29:55 pm
Just googled to see if I could find where I’d read about it. Not sure if this article was it. There’s an explanation as to how they (the BBC) analysed it at the bottom of the article.

https://www.bbc.co.uk/news/science-environment-66670132

Think what I’d read was more just a couple of campaigners who’d done their own analysis but had essentially done and found the same thing.

 

SimplePortal 2.3.7 © 2008-2024, SimplePortal