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Clifden Flooding

2

Comments

  • Registered Users Posts: 6,720 ✭✭✭timmyntc


    Popoutman wrote: »
    The forestry plantations will have reduced the floodwater peak from what it would have been otherwise - the root systems slow down the runoff. Now, if there was a large swathe of recently felled forestry, that would revert the behaviour to pre-forestry runoff speeds.

    Bogs can take in a lot of water for sure, but only up to a certain rate. Above that rainfall rate the extra runs straight off. Source? I've a mate who is a forestry manager, and I've also observed this behaviour after 25 years of watching floodwater levels on Irish streams with my kayaking background.

    I would suspect that if it were not for the forestry work, there would have been a mudflow/bogflow situation with the peat mobilising similar to that at the Dawn of Hope Bridge in Sligo and that would have been significantly worse for the Clifden residents.

    Forestry would reduce peak flow - except for the drainage ditches which vastly speed up the rate of water runoff.
    I'm not familiar with any of the forestry near clifden, but those I've seen in the past across the country usually have ditches dug for drainage and other reasons - stops the forest floor getting waterlogged in heavy rain, but shifts the problem elsewhere.

    This exact kind of works caused a big bogflow in Leitrim earlier in the year


  • Registered Users Posts: 13,477 ✭✭✭✭sryanbruen


    Radar estimates say between 80-130mm fell locally in 12 hours.

    https://twitter.com/ScottDuncanWX/status/1301189906337800193?s=20


  • Registered Users Posts: 12,752 ✭✭✭✭flazio


    Met Eireann dropped the ball on this one. Mind you it doesn't look like IWC did much better.


  • Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    flazio wrote: »
    Met Eireann dropped the ball on this one. Mind you it doesn't look like IWC did much better.

    Met Éireann did forecast heavy rain, leading to some spot flooding. The Clifden event was due to a combination of runoff of orographic enhancement of rain rates and land usage issues. Surrounding areas didnt have any problem. Nearby Mace Head had only 25 mm overnight.

    As for IWC, he won't be happy about missing that one given that he recently claimed that he is more qualified in Meteorology than anyone in Met Éireann. I shít you not.


  • Closed Accounts Posts: 544 ✭✭✭Hawthorn Tree


    Connemara is amazing after nights of heavy rain. The mountain streams come alive and you can drive through the valleys and marvel at the numerous waterfalls.


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  • Registered Users Posts: 5,853 ✭✭✭Storm 10


    Not a mention of the rain that hit Clifden on the forecast just said warnings still in place forgot to mention Connacht only got the warning at 9am today, now if this had hit Dublin


  • Banned (with Prison Access) Posts: 3,316 ✭✭✭nthclare


    If you ever walk through these modern plantations of forest's you'll notice that the ground is hard and doesn't absorb anything, there's no undergrowth or different canopy's, shrubs and fern's etc they soak up the moisture and the rain is distributed naturally.

    Just your mundane evergreens and that's typical of the mentality of the greed going on in this county, ah sure lads plant away,we'll see the fruit of our success in the future...
    Green shoots and all that stuff.

    Mess around with nature and you'll see how it bites back.

    There's a lot of these forest's in Clare too and the run off is poisonous to river's and lakes.
    But dare you suggest that and you'll have the pitch forks out.

    There's no such thing as a risk assessment or how these artificial woods will impact the environment or whatever is in its path.
    A Horticulture student from the 80's and 90's would know about Risk assessment and how topography works.

    Whatever they're teaching now in forestry course's and horticulture definitely isn't as practical as it was.

    No doubt this is going to create a lot of finger wagging in Clifden.
    A canopy forest layer is there for a reason...

    FACEPALM


  • Registered Users Posts: 15,944 ✭✭✭✭Villain


    It is a bit odd how Galway was left out of the warning, ARPEGE model forecast was pretty good for it:

    https://twitter.com/carlowweather/status/1301186494275694592?s=21


  • Registered Users Posts: 6,235 ✭✭✭Oneiric 3


    More rain fell here in this eastern part of Galway (which wasn't that much compared to Connemara) in the last 24 hours than from 'Emma'. We got a yellow rainfall warning for Emma, but none for today's event, except when it was already in full swing.

    I'm not blaming Met Eireann for this as the models right up to this were all over the place, but once again it shows that these county specific warnings are useless and for large western counties such as Galway, just too encompassing. The climate of this part of Galway, and even more so as you go further east into the country, has more in common with that of the midlands than the actual west coast, which is always prone to the feeling the full impacts of the Atlantic's tantrums.

    New Moon



  • Registered Users Posts: 6,235 ✭✭✭Oneiric 3


    Rainfall totals since 1am (up to 9pm) on all of the reporting stations on the Met Eireann 'WOW' site:

    0Ln0S7V.png

    New Moon



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  • Registered Users Posts: 14,229 ✭✭✭✭ednwireland


    upto 49.4 for sw donegal now


  • Registered Users Posts: 3,466 ✭✭✭jetfiremuck


    there is another depression leaving the coast of North Carolina on its way. Unless there is a serious discussion and funding to dredge the rivers which not ideal is the least intrusive method for offering some cushion to water outflows. tree plantations etc are not going to revert to pre planted state anytime soon. Also consider the underlying damage of fast flowing rivers on embankments and structures.


  • Registered Users Posts: 9,601 ✭✭✭Birdnuts


    Popoutman wrote: »
    The forestry plantations will have reduced the floodwater peak from what it would have been otherwise - the root systems slow down the runoff. Now, if there was a large swathe of recently felled forestry, that would revert the behaviour to pre-forestry runoff speeds.

    Bogs can take in a lot of water for sure, but only up to a certain rate. Above that rainfall rate the extra runs straight off. Source? I've a mate who is a forestry manager, and I've also observed this behaviour after 25 years of watching floodwater levels on Irish streams with my kayaking background.

    I would suspect that if it were not for the forestry work, there would have been a mudflow/bogflow situation with the peat mobilising similar to that at the Dawn of Hope Bridge in Sligo and that would have been significantly worse for the Clifden residents.

    The peat in the Sligo case had been damaged already by forestry and windfarm works. Spruce forests are shallow rooted and prone to windthrow on blanket bog so provide little in the way of stability. Also they kill all the ground vegetation which makes the area even more vulnerable to such events


  • Registered Users Posts: 9,601 ✭✭✭Birdnuts


    there is another depression leaving the coast of North Carolina on its way. Unless there is a serious discussion and funding to dredge the rivers which not ideal is the least intrusive method for offering some cushion to water outflows. tree plantations etc are not going to revert to pre planted state anytime soon. Also consider the underlying damage of fast flowing rivers on embankments and structures.

    Failed spectacularly in Bantry only a few weeks ago - we need a proper catchment approach including restoration of natural wetlands. The reasons Naas and Clondalkin do not flood anymore is thanx to the intallation of Reed beds and spillover ponds in upstream parks. Sadly the OPW appears to prefer wasting vast amounts of tax payers money on costly and destructive "hard" solutions that damage fisheries etc.


  • Closed Accounts Posts: 544 ✭✭✭Hawthorn Tree


    Storm 10 wrote: »
    Not a mention of the rain that hit Clifden on the forecast just said warnings still in place forgot to mention Connacht only got the warning at 9am today, now if this had hit Dublin

    I doubt people in Clifden would have done anything different whatsoever if they had been included in a rain warning. They see a lot of rain. And warnings.


  • Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    We will, of course, have the usual suspects on claiming this is no doubt linked to greenhouse gases, bla bla. The same way certain commentators were attributing the Cork flooding to it too, no questions asked. If Clifden has had the worst flood in living memory it is not due to a changing climate, in the same way that that flash flood in Boscastle a few years ago was not linked to a changing climate. But wait, soon enough we'll have Professor Sweeney from Maynooth on Morning Ireland saying that Clifden is yet another sign of our effect on the climate.


  • Registered Users Posts: 6,010 ✭✭✭TheRiverman


    Storm 10 wrote: »
    It's beyond me why people film in portrait mode it's a waste of a good capture of any incident

    TV stations and social media need to ban them.They look so ridiculous.


  • Registered Users Posts: 9,601 ✭✭✭Birdnuts


    We will, of course, have the usual suspects on claiming this is no doubt linked to greenhouse gases, bla bla. The same way certain commentators were attributing the Cork flooding to it too, no questions asked. If Clifden has had the worst flood in living memory it is not due to a changing climate, in the same way that that flash flood in Boscastle a few years ago was not linked to a changing climate. But wait, soon enough we'll have Professor Sweeney from Maynooth on Morning Ireland saying that Clifden is yet another sign of our effect on the climate.

    Indeed - sadly it deflects from the land use issues and poor planning that are by far the main elements that contributes to such events


  • Moderators, Science, Health & Environment Moderators Posts: 11,761 Mod ✭✭✭✭Meteorite58


    That was some rainfall, frightening torrent of water in the video clips.

    Will be interesting to hear if there is conclusive evidence of factors which contributed to such a flash flood or was it just a display of Mother Nature at it's fiercest dropping so much rain over the mountains in a relatively short amount of time.


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  • Registered Users Posts: 2,023 ✭✭✭Donegal Storm


    nthclare wrote: »
    If you ever walk through these modern plantations of forest's you'll notice that the ground is hard and doesn't absorb anything, there's no undergrowth or different canopy's, shrubs and fern's etc they soak up the moisture and the rain is distributed naturally.

    Just your mundane evergreens and that's typical of the mentality of the greed going on in this county, ah sure lads plant away,we'll see the fruit of our success in the future...
    Green shoots and all that stuff.

    Mess around with nature and you'll see how it bites back.

    There's a lot of these forest's in Clare too and the run off is poisonous to river's and lakes.
    But dare you suggest that and you'll have the pitch forks out.

    There's no such thing as a risk assessment or how these artificial woods will impact the environment or whatever is in its path.
    A Horticulture student from the 80's and 90's would know about Risk assessment and how topography works.

    Whatever they're teaching now in forestry course's and horticulture definitely isn't as practical as it was.

    No doubt this is going to create a lot of finger wagging in Clifden.
    A canopy forest layer is there for a reason...

    FACEPALM

    Agreed, for all the talk of fossil fuels and whatnot, Coillte have done more damage to our environment than most over the past 30 years. Another thing you notice when walking through the plantations is that they extremely dark and utterly devoid of any other plant or animal life with the ground entirely covered in pine needles (which I'd guess helps water runoff). Not to mention they turn the area into something akin to a post nuclear wasteland when coillte decide to cash in and chop them down. They're unfortunately an ever increasing feature of the landscape here in Donegal as well.


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  • Banned (with Prison Access) Posts: 1,306 ✭✭✭bobbyy gee


    When there's flooding
    I always take the high ground


  • Registered Users Posts: 32,634 ✭✭✭✭Graces7


    One of the news reports quotes older Clifden residents remembering floods there in August in the '40s.


  • Banned (with Prison Access) Posts: 3,316 ✭✭✭nthclare


    Agreed, for all the talk of fossil fuels and whatnot, Coillte have done more damage to our environment than most over the past 30 years. Another thing you notice when walking through the plantations is that they extremely dark and utterly devoid of any other plant or animal life with the ground entirely covered in pine needles (which I'd guess helps water runoff). Not to mention they turn the area into something akin to a post nuclear wasteland when coillte decide to cash in and chop them down. They're unfortunately an ever increasing feature of the landscape here in Donegal as well.

    Coilte is there for a reason and one reason only I'll leave people to their own conclusion.

    Indeed their plantations are wastelands and peppered in pine needles and the soil is basically useless for biodiversity.
    I work with tree's and fortunately I don't work in these barren wastelands


  • Banned (with Prison Access) Posts: 3,316 ✭✭✭nthclare


    We will, of course, have the usual suspects on claiming this is no doubt linked to greenhouse gases, bla bla. The same way certain commentators were attributing the Cork flooding to it too, no questions asked. If Clifden has had the worst flood in living memory it is not due to a changing climate, in the same way that that flash flood in Boscastle a few years ago was not linked to a changing climate. But wait, soon enough we'll have Professor Sweeney from Maynooth on Morning Ireland saying that Clifden is yet another sign of our effect on the climate.

    And because he's a professor uneducated people will believe him if that's his observation.

    If it takes a few days to make a sexy calculation which is the usual waffle you'll hear from someone who uses climate change to put a sticky plaster on another disaster.

    It would be interesting to create a model of Clifden and its local topography and see how using different scenarios the town got flooded.

    Climate change is like a new religion, ah sure just mention climate change that'll quiten them.
    Nobody's going to challenge that.

    Then some guy in a suit and a pair of wellies will arrive in the town like a saviour and shake hands actually no shaking hands, he'll look around and chat with the peasants and his entourage will be introducing him to the locals who's homes and businesses are destroyed.
    Nodding his head, fake smiles and like a magician he'll pull a limp rabbit out of his hat.
    Called a flood relief package.

    You know the types they turn up at funerals and pretend they really care and are a man of the people.

    It's common knowledge that the engineer's of today aren't as clever and able to fix waterworks like they did years ago.

    I know some old guy's in their 70's and 80's who could tell people where all the flood plains are, where there's well's and turloughs and where if you block one spot there,the water will flow off that way and it'll disperse without causing any damage.
    I've seen it happen during the late 90's in a place near Ennis , an aul guy told the engineer's not to be digging there and building.
    No the youthful clean cut engineer laughed it off.

    Well what do you know that place did flood and yep, climate change was the response.

    Not the engineer's or councils fault.


  • Registered Users Posts: 5,885 ✭✭✭OldRio


    Popoutman wrote: »
    The forestry plantations will have reduced the floodwater peak from what it would have been otherwise - the root systems slow down the runoff. Now, if there was a large swathe of recently felled forestry, that would revert the behaviour to pre-forestry runoff speeds.

    Bogs can take in a lot of water for sure, but only up to a certain rate. Above that rainfall rate the extra runs straight off. Source? I've a mate who is a forestry manager, and I've also observed this behaviour after 25 years of watching floodwater levels on Irish streams with my kayaking background.

    I would suspect that if it were not for the forestry work, there would have been a mudflow/bogflow situation with the peat mobilising similar to that at the Dawn of Hope Bridge in Sligo and that would have been significantly worse for the Clifden residents.

    I find it terribly worrying that your 'mate' is in the position he is.


  • Registered Users Posts: 1,363 ✭✭✭Popoutman


    OldRio wrote: »
    I find it terribly worrying that your 'mate' is in the position he is.

    Why would you think that? They're good at what they do, why would that cause you in particular any anxiety? Maybe you should go and have a chat with a professional about being over anxious about irrelevant items.

    Anyway, back on-topic.

    The flooding is completely understandable. It's not the fault of Coillte, it's not the fault of the council, it's not the fault of the engineers. It is very simply too much rain in too short a time on land that was already over-capacity, leading to a large very short pulse of water coming down the streams into the Owenglin. The handwaving about Coillte and forestry cover shows a little bit of a lack of understanding about how things work in reality. How many of you have been on a saturated mountain bog in the middle of a typical Irish Atlantic storm, and then gone under cover of nearby forestry? I would suspect very few. I have, walking upriver with a kayak on the shoulder to paddle an in-flood stream. The bog was sheeting water along the surface and had huge runoff into the streams, and the forestry areas were wet but not flowing. Forestry cover, even the Coillte plantations, delays the flood pulse significantly compared to bare mountain bog.

    We had an incredibly wet end to August. That's a simple observation. Whether or not the river flooded like that in living memory is of no real use, as it's likely that a flood of this level difference is a few-hundred year event based on the topography of the area. The lack of decent record keeping of river levels in our lightly populated areas is no indicator that flooding didn't happen. It's a little fearmongering to think that the flooding was new and unusual - it's just rare.

    What is likely however is that the overall climate change will lead to more of the extreme weather events, as there's more energy available in the atmosphere for the water cycle to move that energy around, in a bit of a positive feedback loop. Climate-change deniers can be as shrill as they want as I have already seen in this thread, it won't change the outlook of more of this type of situation to come.

    The climate change situation is unfortunate, it's annoying, but maybe we can do some local things like move away from watercourses, be smarter about where new infrastructure is built, be smarter about the management of rivers. Notably dredging is a dumb idea most of the time, and cannot be usefully done on rock-floored geologically young rivers to any real extent. There are well-known methods to slow the pulses of floods, but the NIMBY mentality prevents them being put into place, and that is going to be one of the tougher things we as a nation will have to deal with in our mid-term future.

    Anywhere in the country would have had similar issues with the water levels given the previous fortnight of rain, >60mm of water in a few hours will overload the majority of small Irish river basins, leading to the kind of sights seen.

    Something else that we should be cognisant of with the Clifden floods and other such localised short-term weather phenomena, is that we have many more people with recording devices available to take video and communicate that out within a very short space of time than even a decade ago and certainly compared to two decades ago. We find out about it faster, and we see the effects and the "first-person view" much sooner and the whole experience feels more visceral. Add to this that the social media platforms are training us all to be more angry and more fearful and generally more emotional of today's life, these types of events raise more harder emotional responses with more people that the same event thirty years ago would have done.


  • Banned (with Prison Access) Posts: 3,316 ✭✭✭nthclare


    Popoutman wrote: »
    Why would you think that? They're good at what they do, why would that cause you in particular any anxiety? Maybe you should go and have a chat with a professional about being over anxious about irrelevant items.

    Anyway, back on-topic.

    The flooding is completely understandable. It's not the fault of Coillte, it's not the fault of the council, it's not the fault of the engineers. It is very simply too much rain in too short a time on land that was already over-capacity, leading to a large very short pulse of water coming down the streams into the Owenglin. The handwaving about Coillte and forestry cover shows a little bit of a lack of understanding about how things work in reality. How many of you have been on a saturated mountain bog in the middle of a typical Irish Atlantic storm, and then gone under cover of nearby forestry? I would suspect very few. I have, walking upriver with a kayak on the shoulder to paddle an in-flood stream. The bog was sheeting water along the surface and had huge runoff into the streams, and the forestry areas were wet but not flowing. Forestry cover, even the Coillte plantations, delays the flood pulse significantly compared to bare mountain bog.

    We had an incredibly wet end to August. That's a simple observation. Whether or not the river flooded like that in living memory is of no real use, as it's likely that a flood of this level difference is a few-hundred year event based on the topography of the area. The lack of decent record keeping of river levels in our lightly populated areas is no indicator that flooding didn't happen. It's a little fearmongering to think that the flooding was new and unusual - it's just rare.

    What is likely however is that the overall climate change will lead to more of the extreme weather events, as there's more energy available in the atmosphere for the water cycle to move that energy around, in a bit of a positive feedback loop. Climate-change deniers can be as shrill as they want as I have already seen in this thread, it won't change the outlook of more of this type of situation to come.

    The climate change situation is unfortunate, it's annoying, but maybe we can do some local things like move away from watercourses, be smarter about where new infrastructure is built, be smarter about the management of rivers. Notably dredging is a dumb idea most of the time, and cannot be usefully done on rock-floored geologically young rivers to any real extent. There are well-known methods to slow the pulses of floods, but the NIMBY mentality prevents them being put into place, and that is going to be one of the tougher things we as a nation will have to deal with in our mid-term future.

    Anywhere in the country would have had similar issues with the water levels given the previous fortnight of rain, >60mm of water in a few hours will overload the majority of small Irish river basins, leading to the kind of sights seen.

    Something else that we should be cognisant of with the Clifden floods and other such localised short-term weather phenomena, is that we have many more people with recording devices available to take video and communicate that out within a very short space of time than even a decade ago and certainly compared to two decades ago. We find out about it faster, and we see the effects and the "first-person view" much sooner and the whole experience feels more visceral. Add to this that the social media platforms are training us all to be more angry and more fearful and generally more emotional of today's life, these types of events raise more harder emotional responses with more people that the same event thirty years ago would have done.

    I identify with your observations about social media training people to be more hostile and strident.
    And I can hold my hand up and humble brag that I'm no Saint myself and trying to re-read my post's so as not to upset anyone else or get triggered because I have an emotional or financial interest in the subject matter.

    I'm a fecker for going off on tangents amyhow I hope the people in Clifden will be looked after and the right engineer's figure out the cause and solution to the disaster and maybe some financial assistance will come their way.


  • Registered Users Posts: 1,363 ✭✭✭Popoutman


    nthclare wrote: »
    I identify with your observations about social media training people to be more hostile and strident.
    And I can hold my hand up and humble brag that I'm no Saint myself and trying to re-read my post's so as not to upset anyone else or get triggered because I have an emotional or financial interest in the subject matter.

    There are reasons I haven't logged into FB since the start of 2018, that I have Twitter set for as few notifications and retweets as possible, as well as strongly pulling back from the other forums I've been a member of for a decade or two. I've also found that to protect my mental health I now I rarely participate in a lot of the discussions I see or read unless it's either something that I have a fair bit of experience in and I can be useful to the thread or that I have a strong current interest in. I rarely nowadays try to help educate the incorrect, as I found that is a route to frustration and unhappiness. Thankfully I don't feel that from Boards, but I am also careful about my approach to everyone here.
    nthclare wrote: »
    I'm a fecker for going off on tangents amyhow I hope the people in Clifden will be looked after and the right engineer's figure out the cause and solution to the disaster and maybe some financial assistance will come their way.

    I'm not confident that any cause will be easily identifiable other than too much rain. My impression is that after the initial cleanup of the mud and standing water, there may be a long look taken at whether it's a good idea to live that close to a river that has now been proven to be able to flash that high. It really sucks to have to consider moving from what may have been a family home, but it's better that than have to deal with more property damage or the deaths of family members or pets.

    I think Clifden, even though the flooding was terrible, got off lightly compared to the possibility of what could happen. It's certainly possible to have a debris flow started from movement of the land when that saturated and lubricated, and bad as the flow of water is it is nothing compared to the damage that a flow of rock or mud can bring.


  • Registered Users Posts: 4,366 ✭✭✭jackboy


    Popoutman wrote: »
    We had an incredibly wet end to August. That's a simple observation. Whether or not the river flooded like that in living memory is of no real use, as it's likely that a flood of this level difference is a few-hundred year event based on the topography of the area. The lack of decent record keeping of river levels in our lightly populated areas is no indicator that flooding didn't happen. It's a little fearmongering to think that the flooding was new and unusual - it's just rare.

    I think sometimes a small localised area just gets extreme rain and floods because of this. It might be as simple as that. I remember a few years ago there was extreme flooding in Ennis. The water was flowing over the boundary wall of st flannans school like a waterfall. Never saw the like before or since in my life.


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  • Registered Users Posts: 15,853 ✭✭✭✭Spanish Eyes


    Glad I live on the top of a hill. That's in Dublin BTW.

    I do understand that Clifden has never experienced the like of this up to now. But seriously get up high with your house.


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