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Clontarf bike lane - what a shambles

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    #92
    ted1
    Registered Users Posts: 23,536 ✭✭✭✭ted1


    mr spuckler wrote: »
    what's the deal with the steps down to sea-level along the new stretch? it doesn't look like there's any form of barrier there, so if waters rise above the height of the path they'll spill over at this point...have i missed something?
    Probably metal flood gates are provisioned for. In high tides etc the council put them in in place.


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    #93
    Vizzy
    Registered Users Posts: 2,537 ✭✭✭Vizzy


    odyssey06 wrote: »
    ALL the councillors didn't even vote to fund the reduction... some of the councillors from the clontarf-D3 area are doubtless responding to local pressure, the question is why councillors not from clontarf-D3 would vote in favour of it... unless they thought it was the right thing to do or were paying it forward to call in favours down the line.

    Even if you assume that they were "paying it forward" , the local Councillors and indeed the others not from the area will not vote for a proposal that is obviously wrong from a Planning Permission point of view. There would have been uproar at the Council if they Councillors thought that they were being deliberately mislead by officials and even if the Councillors didn't raise the roof, then the press certainly would.


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    #94
    odyssey06
    Registered Users Posts: 30,496 ✭✭✭✭odyssey06


    Vizzy wrote: »
    Even if you assume that they were "paying it forward" , the local Councillors and indeed the others not from the area will not vote for a proposal that is obviously wrong from a Planning Permission point of view. There would have been uproar at the Council if they Councillors thought that they were being deliberately mislead by officials and even if the Councillors didn't raise the roof, then the press certainly would.

    Well what's your theory on why did they vote for it? There can't be too many votes in the views of coast road motorists, if that's the alternative theory.

    "To follow knowledge like a sinking star..." (Tennyson's Ulysses)



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    #95
    Vizzy
    Registered Users Posts: 2,537 ✭✭✭Vizzy


    ted1 wrote: »
    Probably metal flood gates are provisioned for. In high tides etc the council put them in in place.

    Even simpler than that, there would be flood valves inserted in the wall or be connected to the drains that will open when the water from the land flows through them but will remain sealed shut if there is no flow or if the flow comes from the sea side.


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    #96
    Vizzy
    Registered Users Posts: 2,537 ✭✭✭Vizzy


    odyssey06 wrote: »
    Well what's your theory on why did they vote for it? There can't be too many votes in the views of coast road motorists, if that's the alternative theory.

    Why did they vote fro what ?

    The Councillors voted to lower the wall. I presume that they all had their reasons, be it local pressure from voters or whatever, but, my point is that they were not doing this to save the blushes of council officials.


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    #97
    recedite
    Closed Accounts Posts: 13,992 ✭✭✭✭recedite


    Anyone see that footage on RTE last week of the flood in Galway?
    There was a guy standing in a flooded building fiddling around trying to fit his floodgate at the front door. These things are great if somebody goes out and fits them before the flood.


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    #98
    odyssey06
    Registered Users Posts: 30,496 ✭✭✭✭odyssey06


    Vizzy wrote: »
    Why did they vote fro what ?

    The Councillors voted to lower the wall. I presume that they all had their reasons, be it local pressure from voters or whatever, but, my point is that they were not doing this to save the blushes of council officials.

    Maybe they were voting to save their own blushes, I think they did vote in favour of the original proposal...

    "To follow knowledge like a sinking star..." (Tennyson's Ulysses)



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    #99
    ted1
    Registered Users Posts: 23,536 ✭✭✭✭ted1


    Vizzy wrote: »
    ted1 wrote: »
    Probably metal flood gates are provisioned for. In high tides etc the council put them in in place.

    Even simpler than that, there would be flood valves inserted in the wall or be connected to the drains that will open when the water from the land flows through them but will remain sealed shut if there is no flow or if the flow comes from the sea side.
    Any links?

    I was thinking along these lines
    https://goo.gl/images/3YT1bd


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    #100
    Vizzy
    Registered Users Posts: 2,537 ✭✭✭Vizzy


    Something like this I would think - look at the HDPE Valves.

    http://www.waterfrontfc.co.uk


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    #101
    recedite
    Closed Accounts Posts: 13,992 ✭✭✭✭recedite


    Vizzy wrote: »
    Something like this I would think - look at the HDPE Valves.

    http://www.waterfrontfc.co.uk
    OK. but somebody would still need to go out just before the flood and install the floodgates where the wall is breached at the steps.


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    #102
    expectationlost
    Registered Users Posts: 11,916 ✭✭✭✭expectationlost


    some documentation would help odyssseys claims


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    #103
    odyssey06
    Registered Users Posts: 30,496 ✭✭✭✭odyssey06


    expectationlost wrote: »
    some documentation would help odyssseys claims

    https://www.clontarf.ie/news/clontarf-sea-wall-independent-heights-survey

    Johnny Morrissey of the Dollymount sea scouts has measured the max height of the new wall and it's 4.25 ... how can they fit the cladding to that and not breach the height?

    "To follow knowledge like a sinking star..." (Tennyson's Ulysses)



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    #104
    ted1
    Registered Users Posts: 23,536 ✭✭✭✭ted1


    Vizzy wrote: »
    Something like this I would think - look at the HDPE Valves.

    http://www.waterfrontfc.co.uk
    I don’t see how they would cover a 5 ft opening in a wall where there’s steps.


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    #105
    Vizzy
    Registered Users Posts: 2,537 ✭✭✭Vizzy


    ted1 wrote: »
    I don’t see how they would cover a 5 ft opening in a wall where there’s steps.

    Not familiar with the area so I'm don't know about steps etc. but in the normal course of events (i.e. when there is serious rainfall with a danger of flooding on the "land side" of the wall) the valves will do the job.
    If there is likely to be flooding from the sea then you would need flood gates at any steps etc.
    In other areas of the country there are also pumps on the land side of the flood defences to actually pump the water through the valves when the flood level on the sea side is higher than the valves but still lower than the flood walls.
    Ennis, Clonmel and Waterford have these I think.


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    #106
    Vizzy
    Registered Users Posts: 2,537 ✭✭✭Vizzy


    Here is an image of the defences in Clonmel. Not much chance of a motorist getting much of a view of the river.

    http://www.nationalist.ie/news/local-news/159230/Clonmel-s-multi-million-euro-flood.html


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    #107
    odyssey06
    Registered Users Posts: 30,496 ✭✭✭✭odyssey06


    Vizzy wrote: »
    Here is an image of the defences in Clonmel. Not much chance of a motorist getting much of a view of the river.

    http://www.nationalist.ie/news/local-news/159230/Clonmel-s-multi-million-euro-flood.html

    There might be... as Clonmel has a demountable section added when flood warnings are in place.

    "The Clonmel Flood Relief Scheme is nearing completion, and will provide protection to a 1 in. 100 year standard from the River Suir through a series of walls, embankments and demountable sections which are put in place following receipt of a flood warning by the local authority"
    http://www.tipperarycoco.ie/sites/default/files/FINAL%20SFRA.pdf

    I'm confused as to why Clonmel can include demountable sections and meet a 1 in 100 year standard but if Clontarf look for the same they are castigated in the media as whinging NIMBYs???

    "To follow knowledge like a sinking star..." (Tennyson's Ulysses)



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    #108
    Vizzy
    Registered Users Posts: 2,537 ✭✭✭Vizzy


    Even without the demountable portion the wall is about shoulder level ( ref the guy in the picture) plus you have the height of the footpath at about 6 inches ,so unless you are driving a bus or an articulated truck you wont see over it as you drive.


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    #109
    Carawaystick
    Registered Users Posts: 8,779 ✭✭✭Carawaystick


    What's the height of the wall from the footpath?


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    #110
    Vizzy
    Registered Users Posts: 2,537 ✭✭✭Vizzy


    Carawaystick wrote: »
    What's the height of the wall from the footpath?

    In Clontarf there is a footpath of maybe 6" 150mm, then the cyclepath then the wall of 2ft 600mm or 2ft 6"750mm https://goo.gl/maps/KZfbsyU8FNH2
    In Clonmel the wall looks like 4ft 1200mm high and then the demountable part is another 4 ft1200mm on top of that.


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    #111
    tomasrojo
    Registered Users Posts: 11,769 ✭✭✭✭tomasrojo


    There is a bewildering amount of Imperial in this thread.


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    #112
    tomasrojo
    Registered Users Posts: 11,769 ✭✭✭✭tomasrojo


    "1 in 100 year". Is that projected, or historical? I think the historical data is about to be pretty irrelevant.


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    #113
    Vizzy
    Registered Users Posts: 2,537 ✭✭✭Vizzy


    tomasrojo wrote: »
    There is a bewildering amount of Imperial in this thread.

    Fixed that now for all the hipsters :D


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    #114
    tomasrojo
    Registered Users Posts: 11,769 ✭✭✭✭tomasrojo


    Quick work, Vizzy!!


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    #115
    Vizzy
    Registered Users Posts: 2,537 ✭✭✭Vizzy


    tomasrojo wrote: »
    "1 in 100 year". Is that projected, or historical? I think the historical data is about to be pretty irrelevant.

    Nothing to do with 100 years.

    https://albertawater.com/how-are-flood-maps-created-in-alberta/what-is-a-1-100-year-flood


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    #116
    tomasrojo
    Registered Users Posts: 11,769 ✭✭✭✭tomasrojo


    Oh yeah, I get the probabilistic origins of the term, but is the use here based on frequency historically, or predicted using sea-level and climate-change predictions? The former, I assumed.


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    #117
    Vizzy
    Registered Users Posts: 2,537 ✭✭✭Vizzy


    Can't honestly say, but I would think that whatever Consultancy firm was employed to design the current scheme would be using flood mapping models.
    How they are compiled, I simply don't know but I would hope that is was a bit more in depth than "we had an awful sup of rain in 1954, so be better make sure we build it high enough"


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    #118
    Effects
    Registered Users Posts: 9,760 ✭✭✭Effects


    recedite wrote: »
    Does anybody know what lets freshwater flooding through this wall out into the sea, but stops seawater flooding coming back the other way?

    Gravity.


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    #119
    expectationlost
    Registered Users Posts: 11,916 ✭✭✭✭expectationlost


    odyssey06 wrote: »
    https://www.clontarf.ie/news/clontarf-sea-wall-independent-heights-survey

    Johnny Morrissey of the Dollymount sea scouts has measured the max height of the new wall and it's 4.25 ... how can they fit the cladding to that and not breach the height?
    official documentation, you said that DCC breeched its own planning therefore the answer should be in their docs.


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    #120
    mr spuckler
    Registered Users Posts: 3,113 ✭✭✭mr spuckler


    mr spuckler wrote: »
    what's the deal with the steps down to sea-level along the new stretch? it doesn't look like there's any form of barrier there, so if waters rise above the height of the path they'll spill over at this point...have i missed something?
    ted1 wrote: »
    Probably metal flood gates are provisioned for. In high tides etc the council put them in in place.

    yeah i've looked and there doesn't appear to be either an inset to sit them into or brackets to take them.
    Vizzy wrote: »
    Even simpler than that, there would be flood valves inserted in the wall or be connected to the drains that will open when the water from the land flows through them but will remain sealed shut if there is no flow or if the flow comes from the sea side.
    Vizzy wrote: »
    Not familiar with the area so I'm don't know about steps etc. but in the normal course of events (i.e. when there is serious rainfall with a danger of flooding on the "land side" of the wall) the valves will do the job.
    If there is likely to be flooding from the sea then you would need flood gates at any steps etc.
    In other areas of the country there are also pumps on the land side of the flood defences to actually pump the water through the valves when the flood level on the sea side is higher than the valves but still lower than the flood walls.
    Ennis, Clonmel and Waterford have these I think.

    bit of a picture here. i'll try to take a better one myself tomorrow morning.

    there are drains under the road to let water out from St Anne's park - of course the first time they were tested in heavy rainfall last June they backed up and the road was flooded as a result...


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    #121
    Vizzy
    Registered Users Posts: 2,537 ✭✭✭Vizzy


    mr spuckler wrote: »
    yeah i've looked and there doesn't appear to be either an inset to sit them into or brackets to take them.





    bit of a picture here. i'll try to take a better one myself tomorrow morning.

    there are drains under the road to let water out from St Anne's park - of course the first time they were tested in heavy rainfall last June they backed up and the road was flooded as a result...

    Is that a pic of the current set-up ? cos there is capping on the wall and I got the impression from the discussion thus far that when the capping was to be installed that it would be over the permitted height in the planning permission and that was the reason that the wall now needs to be lowered.
    If the wall is to prevent flooding there will have to be some way of "waterproofing " the gaps i.e. flood gates that can be removed.

    As regards the drains backing up, they may simply be "existing drains" and not form part of the flood relief scheme.
    Did the road flood during heavy rain previously ?

    Another issue to note is that once the wall stops the sea from flooding the area, it also stops water escaping the other way unless there is proper drainage/valves/pumping in place


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