Dams, Rivers and Flood Management in Ireland

Amtmann · 23-11-2009 9:46pm #1

Here is an OPW document relating to dams, flooding and the ESB in Ireland. There has been a lot of postdiluvian commentary Leeside that the ESB is to blame for the scale of the flooding of Cork and the harm done to the city's water treatment plant because of the organisation's alleged failure to release water steadily at Insicarra Dam before the heavy rains, which were of course forecasted.

Discuss!

KevR · 23-11-2009 11:25pm

I thought they couldn't release any water for a period before the flood because they were searching the river for a missing person. And then there were fears that the dam could burst so they had to release it rapidly.

Sponge Bob · 23-11-2009 11:33pm

Dublin Limerick and Cork are downstream of major dams , Limerick of two .

bk · 24-11-2009 9:52am

KevR wrote: »

I thought they couldn't release any water for a period before the flood because they were searching the river for a missing person. And then there were fears that the dam could burst so they had to release it rapidly.

Yes, that is what I've heard from family in Cork too, that they hadn't been releasing water for the last 6 days before the flooding due to the search for a body.

Very sad situation.

munchkin_utd · 24-11-2009 11:12am

Maybe the building of the dams can be seen as Ireland being progressive during times of crisis.

The ballyshannon scheme was approved in April 1945, at a time when Ireland was sufering rashioning during the emergency, at a cost of £3,115,500 (excluding the necessary transmision lines)

Theres a map and list of workings required in the Dail records.
http://www.irishstatutebook.ie/1945/en/si/0086.html

Hopefully the current government is allowed to plan for the future during the current times of crisis and gets the Dart Underground/ Metros/ new luas etc.

mikemac · 24-11-2009 11:15am

munchkin_utd wrote: »

Hopefully the current government is allowed to plan for the future during the current times of crisis and gets the Dart Underground/ Metros/ new luas etc.

And projects for cities other then Dublin too

GeneHunt · 24-11-2009 12:01pm

I was reading a few threads from the leeside in relation to the flooding and the predicament the ESB was in leading up to Friday last (20th Nov). Firstly I think I should state that I was not affected by these floods to date.

It appears the ESB delayed the releasing of water due to the search for a missing person. It this is true or not, I don’t know.

What if! If it is true and the ESB had decided to released water to avert flooding later in the week and if some people got into difficulty or if someone was to drown in this search for this missing person. Then we would have angry people and rightly so pointing fingers at the ESB for doing this. Dammed if you do and dammed if you don’t! Pardon the pun!

To the best of my knowledge no one died in the Cork floods last weekend, and hats off to all who helped in making that happen. It was only properties that got damaged and before someone shoots me down for saying that, yes it is very easy for me to say that when I wasn’t effected in these floods, I’m sorry and it’s terrible for all the people affected around the country.

I think I heard a spokesman from the ESB on Radio one (Drivetime) on Friday evening last, anyway according to the him, the amount of water flowing into the Inniscarra catchment area was in excess of 800m3/sec and they released 500m3/sec through the dam. Large parts of the country had very heavy rain over the last few weeks. In fact on that Drivetime programme they reported November as the wettest on record, even though it was only the 20th of the month. I saw the path of the weather system which crossed the country late last week; unfortunately this system snaked its way cross the southern half of the country and dumped large quantities of water as it travelled. Rivers can only take so much…

cjpm · 24-11-2009 12:29pm

I must admit i was very surprised when the ESB said it was a 1 in 800 year event, i just thought they were trying to cover their own backsides.

Then at the week-end i was walking along a little river/stream close to my home place and i was surprised to see that there was sand and silt all over the fields adjacent to it, i had never seen this river to flood at this location before. The rain that fell must have been unreal.

Getting back to the dams, it's such a pity that in high flow seasons more power couldn't be generated, it's such a waste just letting it off over the spillway. Now i know that high flow volumes can be around 10 times low flow volumes, but if there were a few extra turbines that could be used in the wet season wouldn't be a great use of some of the available water. Then in the dry periods different turbines could be used to allow maintenace etc...

brandon_flowers · 25-11-2009 12:43am

GeneHunt wrote: »

I was reading a few threads from the leeside in relation to the flooding and the predicament the ESB was in leading up to Friday last (20th Nov). Firstly I think I should state that I was not affected by these floods to date.

It appears the ESB delayed the releasing of water due to the search for a missing person. It this is true or not, I don’t know.

What if! If it is true and the ESB had decided to released water to avert flooding later in the week and if some people got into difficulty or if someone was to drown in this search for this missing person. Then we would have angry people and rightly so pointing fingers at the ESB for doing this. Dammed if you do and dammed if you don’t! Pardon the pun!

To the best of my knowledge no one died in the Cork floods last weekend, and hats off to all who helped in making that happen. It was only properties that got damaged and before someone shoots me down for saying that, yes it is very easy for me to say that when I wasn’t effected in these floods, I’m sorry and it’s terrible for all the people affected around the country.

I think I heard a spokesman from the ESB on Radio one (Drivetime) on Friday evening last, anyway according to the him, the amount of water flowing into the Inniscarra catchment area was in excess of 800m3/sec and they released 500m3/sec through the dam. Large parts of the country had very heavy rain over the last few weeks. In fact on that Drivetime programme they reported November as the wettest on record, even though it was only the 20th of the month. I saw the path of the weather system which crossed the country late last week; unfortunately this system snaked its way cross the southern half of the country and dumped large quantities of water as it travelled. Rivers can only take so much…

Yes it is true about the search for the body and amazingly the body was recovered yesterday.

I dont think the ESB can be held responsible, they were more than likely asked not to release water so the search went on. Naturally it would take a cold heart to put a few MW of power in the way of a family finding their son. No matter what the ESB did, Cork would have been flooded regardless. The volume of water still in the River Lee is still huge.

If mother nature wants to flood someplace mother nature will flood it, no dam or flood relief schemes will stop it.

Amtmann · 26-11-2009 11:27am

THE ESB's strategic Inniscarra hydroelectric dam came within four centimetres of being overwhelmed by flood waters last Thursday.
The disclosure came as two senior Cork politicians -- junior minister Billy Kelleher (FF) and opposition energy spokesman Simon Coveney (FG) -- called for an independent assessment of the Lee Valley's flood management capability.
Demands for an inquiry came against the backdrop of repeated warnings in expert reports that the capacity of lakes on the River Lee above the dam were simply not sufficient to cope with "an extreme weather event".
It has now emerged that the ESB desperately tried to lower water levels in both Inniscarra and Carrigadrohid lakes between Tuesday and Thursday last week with smaller dam releases, but such was the deluge that hit the valley they had no option but to order the release of 535 tonnes of water per second on Thursday.
At the flood peak, waters in Inniscarra lake came within 4cm of spilling over the dam wall. The total rainfall above the dam amounted to more than 800 tonnes of water per second entering the lakes at one point.
It has also been confirmed that the ESB issued two flood warnings -- at 11am and 4pm last Thursday -- but most Cork city centre residents were unaware of that when the torrent hit the city.
One man had to be taken from bed in his house at Grenville Place, where a quay wall collapsed, with flood waters just inches below his mattress.
"This (inquiry) is not about blame, it is all about ensuring that this never, ever happens again in Cork," Deputy Coveney said.
Mr Kelleher endorsed the inquiry call, adding that it was clear Cork's flood management and flood defence system needed to be urgently overhauled.
The rainfall which hit the Lee Valley last week was double what the ESB and local authorities had been expecting -- almost 90mm compared with a prediction of 40mm.
The clean-up and repair bill in the city is now expected to exceed €100m, with 50,000 residents likely to be without running water until next Sunday, a period of 10 days.
Cork City Council engineers are still working round-the-clock to repair the damaged Lee Fields Water Station, but mains water will only be restored when experts are satisfied there is no risk of contaminated water entering the system. At one point, the station was under almost 20 feet of murky flood waters.
Hotels which have been offering bathing facilities to flood-hit families said they have been overwhelmed by the response.
- Ralph Riegel
Irish Independent

http://www.independent.ie/national-news/dam-just-4cm-from-being-overwhelmed-1953754.html

:eek:

Jim Martin · 28-11-2009 11:51am

In response to an email which I sent to GDACS (Global Flood Alerts System) wondering why they had no data for Ireland, I received the following reply:

"Dear Jim,

Unfortunately, due to limitations in mandate, GDACS doesn’t cover floods in Europe. We have another group working on floods in Europe (http://efas.jrc.ec.europa.eu/), but their data and alerts are restricted to water authorities. Please contact jutta.thielen@jrc.ec.europa.eu for more information on EFAS.

Best regards,

Tom De Groeve

tom.de-groeve@jrc.ec.europa.eu

+390332786340"

So, unfortunately, nothing available for the public!

Sponge Bob · 30-11-2009 1:40am

I do not believe the '4cm' statement by the ESB. Not in the least . They would have force released at 4 metres never mind 4cm.

They were entitled to release at 4 metres anyway.

L1011 · 30-11-2009 9:59am

I would take it that it means 4cm off the level thats seen as dangerous, rather than 4cm off the top of the dam. 4cm off the top of the dam would have meant it could have been overwhelmed at any second.

KevR · 01-12-2009 12:33am

Lively debate on the Front Line on RTE1 at the moment!

KevR · 01-12-2009 1:08am

Mayor of Cork on the Front Line sort of implying that people didn't take the flood warnings seriously because there are quite a few flood warnings which come to nothing.

Hmm...I do live 200km away but I can't recall ever hearing a flood warning for Cork, that is apart from for the recent floods. I was aware that Cork was going to flood before it did and I'm in a different part of the country. I'm sure there were even more warnings in the local media down there.

Whether it was preventable or not, I have no idea. But I certainly don't agree that there wasn't sufficient warning for the floods in Cork.

Amtmann · 02-12-2009 1:02pm

The Frontline was very good on Monday night - but I wish they had let the engineer speak more. That councillor from Monaghan was deplorable.

ohnoigotsick · 02-12-2009 1:11pm

Furet wrote: »

The Frontline was very good on Monday night - but I wish they had let the engineer speak more. That councillor from Monaghan was deplorable.

seriously - it was good ??
I reckon it was chaos - you had everyone shouting the odds at different times with pat the plank fuelling arguments by asking a minister of the environment legal questions about who the people in sallins should sue.
　
　
now while planning has been woeful in this country - everyone shouting the odds at Gormley was a bit much - I'm certainly no green party member but he is trying to bring common sense into planning - I agree with you about he tool from Monaghan - has everything that is wrong with politics.
　
　
as for the lady who bought the apt in sallins - while I feel for her that her house is ruined - she bought it on a flood plain - no one told me it was on a flood plain she says - hello your buying a house you look into these things - as one of the guys I work with said , you should only buy a house on rainy day.
　
　
the engineer was cut off as soon as he started to speak - a sham of a show if you ask me
　
　
　
　
also what was with the guy sitting beside Gormley - he wouldn't look at him when he was speaking ?

Amtmann · 02-12-2009 1:18pm

ohnoigotsick wrote: »

seriously - it was good ??
I reckon it was chaos - you had everyone shouting the odds at different times with pat the plank fuelling arguments by asking a minister of the environment legal questions about who the people in sallins should sue.
　
now while planning has been woeful in this country - everyone shouting the odds at Gormley was a bit much - I'm certainly no green party member but he is trying to bring common sense into planning - I agree with you about he tool from Monaghan - has everything that is wrong with politics.
　
as for the lady who bought the apt in sallins - while I feel for her that her house is ruined - she bought it on a flood plain - no one told me it was on a flood plain she says - hello your buying a house you look into these things - as one of the guys I work with said , you should only buy a house on rainy day.
　
the engineer was cut off as soon as he started to speak - a sham of a show if you ask me
　
also what was with the guy sitting beside Gormley - he wouldn't look at him when he was speaking?

Actually, you're quite right. The rule of the mob certainly prevailed. But that was why I thought it was good - because it showed just how foolish so many people have been, and how they completely abrogate responsibility. I thought Gormley did a good job. I thought he took criticism well while making several good points. The most interesting comments, of course, were made by the engineer and those speaking about river management; but Pat Kenny also made a great point when he raised the issue of building in risky areas, which of course gave the buffoon councillor a chance to shine.

ohnoigotsick · 02-12-2009 1:32pm

Furet wrote: »

Actually, you're quite right. The rule of the mob certainly prevailed. But that was why I thought it was good - because it showed just how foolish so many people have been, and how they completely abrogate responsibility. I thought Gormley did a good job. I thought he took criticism well while making several good points. The most interesting comments, of course, were made by the engineer and those speaking about river management; but Pat Kenny also made a great point when he raised the issue of building in risky areas, which of course gave the buffoon councillor a chance to shine.

to be fair that councillor was rightly stitched up - but he deserved it.
Kenny made a good point to the IFA dude about farmers selling flood plained land to developers.
I can understand frustration, but what's the point of having the window man from athlone on just ranting and raving - I understand his business is flooded but he brought nothing to the debate.
management companies was an issue that should have also been brought up. I'm living here in Galway and am paying - well basically money for nothing - I got onto them this year and said it wasn't good enough as I live in a mixed block of houses and apt - and while the apts have a higher fee - they get services for there money - where as we get public liability insurance for our money - which in no way represents value for money - anyway back on topic - if the management company goes bust it should fall back to the council with them collecting the rate the management company collected

KevR · 02-12-2009 1:47pm

Furet wrote: »

because it showed just how foolish so many people have been, and how they completely abrogate responsibility.

Indeed. That's what struck me most about Monday's Front Line - nobody wanted to accept any responsibility*, they just wanted to blame everyone but themselves.

I actually didn't realise that nearly all rivers/waterways in Ireland are not dredged or maintained at all :eek:.

*If you don't take a flood warning seriously or build/buy on a floodplain you are partly responsible for any flood damage which you incur. I know the government has not done as much as they should to prevent flooding but that doesn't mean you can ignore a flood warning and then blame the government for all the damage to your property. And if it's clear that the government weren't doing enough then you definitely should not be living on a floodplain.

Also, the guy from the Farmer's Association said that towns shouldn't get majority of any new flood defenses because that would be treating rural people like second class citizens.
I couldn't disagree more. Large towns like Ballinasloe should be flood-proofed. Not only do more people have their homes destroyed when a town floods but there was major disruption for everyone travelling between Galway (County Galway 230,000 people) and Dublin (Greater Dublin 1 million people) by road or rail. Large towns and important transport links should definitely be a priority for flood protection, not fields or one off houses. Making towns a priority is not treating rural people as second class citizens, it's spending money for the greater good.

Sponge Bob · 02-12-2009 1:55pm

KevR wrote: »

I actually didn't realise that nearly all rivers/waterways in Ireland are not dredged or maintained at all :eek:.

Yep. There was a flurry of dreding in the 1955 - 1965 timescale and they have let the rivers silt up since.

Gormleys NPWS is responsible for that , they have a culture of objecting willy nilly and have now scared the crap out of the rest of Gormleys department with Euro/Habitat boogie men everywhere you look and have therefore frozen river management at national and local level in the past 20 years .

As long as we have an NPWS things will only get worse. They are utterly arrogant useless tossers of the highest order in the main ( there are one or two nice rangers). Not a single engineer between the lot of them but plenty of snail experts

KevR · 02-12-2009 2:17pm

Sponge Bob, can you remember what they did to the Corrib in Galway below the weir a few years back (possibly 10 or more)? I remember they almost completely stopped the flow of water coming through the weir (apart from a small trickle). There were diggers doing something to the river bed I think but I can't really remember what. Could they have been digging the bed down to increase capacity?

I was in St. Pat's primary school at the time so we were facing onto the river. We used to get the bus home from the Spanish Arch after school and I remember we used to go down onto the river bed and run around near the edge where it was fully dry while waiting for the bus. Imagine if they opened up the weir while we were down there :eek: :pac:.

Sponge Bob · 02-12-2009 3:23pm

You are right Kev. They did dig down the riverbed between the salmon weir and the Wolf Tone bridge. Most of that work was done in the 1950s and was certainly complete by the late 1960s. The Salmon Weir itself was part of that scheme , replacing an earlier structure.

I think there were areas like nuns island discharging sewage into the corrib up to the 1990s and that "interceptor" sewers were installed to reroute this towards Mutton Island during the 1990s remember the turds from the atlanta hotel bobbing past the fisheries tower not too far back

That is what you saw I would think.

ardmacha · 02-12-2009 3:30pm

Making towns a priority is not treating rural people as second class citizens, it's spending money for the greater good.

Any public policy must cater to be greater number of people. But if you build on an area that floods and then build a great wall to prevent the water encroaching there, then the water will flow on and flood somewhere else. If you are living in the other place then government policy might directly lead to you being flooded, or at least to your land being flooded. This would make you a second class citizen.

KevR · 02-12-2009 4:22pm

ardmacha wrote: »

Any public policy must cater to be greater number of people. But if you build on an area that floods and then build a great wall to prevent the water encroaching there, then the water will flow on and flood somewhere else. If you are living in the other place then government policy might directly lead to you being flooded, or at least to your land being flooded. This would make you a second class citizen.

A lot of these towns have never had flooding problems before so I don't think it's a case of building in flood prone areas and then putting in flood protection which directly causes flooding for people elsewhere.

Yes, if you built a town in an area that always flooded and then put in flood protection which resulted in rural areas (which never had floods) being flooded then that would definitely be a case of the rural people being treated as second class citizens.

But, as I said, some of these towns have never had floods and, in my opinion, they should get protection even if it does lead to worse rural flooding outside the town. It's more unfortunate/aweful luck if you happen to live in a rural area outside the town which gets worse floods after the town gets better protection, not 2 tiered citizenship.

Sponge Bob · 02-12-2009 6:20pm

Which bit of wettest November on record do people not understand ??

They have measured November rainfall in Valentia since 1866

2009 was the wettest year in 30 years ...or was that ever ( and with a month to go) ??

November 2009 was the wettest November in 1866 , there are no older rainfall records in the west of ireland than Valentia .

KevR · 02-12-2009 7:25pm

Wettest November on record might suggest that this was a freak occurence. But 2009 being the wettest year ever is worrying, it suggests a trend - I would be surprised if we don't get similar levels of rainfall over the next few years.

We had flash floods in parts of Galway City last summer, something which I had never seen before.

Records are there to be broken...

Carawaystick · 03-12-2009 12:06am

1866 is only about a hundred and forty odd years. It's ten thousand since the last ice age. If records went back all the way then these one in 80 year events would have happened at least 12 times.

Annual weather records are a reasonable concept but arbitrarily dividing the year into 28,29,30 an 31 day chunks of time isn't really any use. A rolling 30 day time is a better way to show exceptional weather.
If the last 15 days of a month are very wet but not record breaking and the next 15 days are very wet but not record breaking, then a monthly record system won't show this as exceptional. A rolling 30 day record will show it as exceptional though.

I was talking to a woman in Clonmel several years ago who reckoned building the shops below the town on the flood plain helped stop the Suir bursting her banks there and causing the river to back up in the town, worse than it usually did. Dunned were considering writing of the shop, levelling it and rebuilding it on stilts with the car park underneath.

I was talking to the Harbour Master in Arklow another time. He showed me the original plans to the piers. the plans state the bar must be dredged or the river will back up and flood.
The port there is closing down gradually and I doubt the owners of the apartments built alongside the Avoca have a sinking fund designed to pay for dredging....

Sponge Bob · 03-12-2009 1:09am

Carawaystick wrote: »

The port there is closing down gradually and I doubt the owners of the apartments built alongside the Avoca have a sinking fund designed to pay for dredging....

How very aptly put ( not)

Amtmann · 07-01-2010 11:52pm

Good programme on the Iniscarra Dam and the flooding in Cork here: http://www.rte.ie/player/#v=1063689

Tech3 · 08-01-2010 12:10am

Very good report on the flooding tonight on primetime.

The report on the Waterways estate in Sallins was interesting to watch but obviously sad for anyone that was affected by the floods. One of the two culverts which lead down stream after the Waterways estate to the river was blocked. One was for the railway line and the other was a road culvert. IE said the culvert for the railway line was fine but the road culvert was poor and needed to be replaced.

Questioned about the road culvert, Kildare county council refused to comment. Either way it was a flood plain and the estate should not have been built there. The council also didnt take quick action on fixing the culvert or replacing it.

Dams, Rivers and Flood Management in Ireland

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