Flooding – dam incompetence

Impetus

Markcheese wrote: »

I was in the city around 6 last night and the water in the north channel was fairly low - but really flowing fast, if the river in the city had been full to the bridges , ( from released river water ) then up stream would have been badly flooded...

It is a matter of management of the discharge rates based on the parts of the city which are least tolerant to high water. As a secondary precaution, these few points of maximum weakness need some construction work to reduce the risk. This would allow more water to be expelled from the system in periods of heavy rainfall.

Growth in Cork is mainly in the suburbs, and has been. The increases commuting distances and times, and makes the place less easy to provide an excellent frequent public transport system in (ie a daytime/evening maximum wait of 5 to 7 mins for a service - be it bus, tram etc and suburban trains working to a clockface timetable). This requires density to work economically. The metro area stretches from Ballincollig to Midleton - which is about 30km. For a population of about 300'000. This is bad planning. A city should be as close to walkable as possible. The risk of flooding is one issue I would take into consideration when deciding where to put a business premises, or indeed live. The core is the obvious location, if it was sustainably accessible at all times - which is not the case.

The powers that be seem to have learned nothing from 2009, and with the odd exception, this discussion seems to be dominated by people who either have a vested interest in "running the place" or seem to enjoy the odd flood as a bit of random excitement, probably because they live on a hill!

TheChizler

I don't think there are vested interests here, just skepticism that you can tell the flow rate of the dam from the water level in the city alone.

hytrogen

Impetus wrote: »

I have no doubt that the release of water is controllable (electro-mechanically) and remotely. In the 2009 flooding, media reports said it was done remotely from Ardnacrusha. It seems to me that there is a culture/instruction within ESB to maximise the use of the water for generation purposes. Instead of proactively dumping water during periods of risk, making maximum use of low tides. To do so you need to be able to monitor the river height in the city centre at the most critical flood risk points, and slowly increase the sluice gate opening, until you are getting close to safe high water mark at these critical points. If this happens you reduce the flow slightly so it continues to maximise the discharge rate, while at the same time not flooding the place.

The entire process should be automatically monitored in real time. However there is nothing to stop one from doing the job manually - even if it means putting observers watching the river in the city at critical times, who can call the control centre on a mobile phone and give the person in the control room feedback.

I am sure ESB is paying met.ie for accurate rainfall forecasts. They are also available here:

http://www.wunderground.com/cgi-bin/findweather/getForecast?query=Cork%2C+Ireland

You click on customise and check the precipitation accum. total, and hourly liquid precipitation boxes and it shows up as green on the chart on an hour by hour basis.

You can even get detailed forecasts further upstream in the Lee - eg
http://www.wunderground.com/q/locid:EIXX3370;loctype:1

OP unfortunately you and the media are completely off the mark with what happened in 2009. (Also searching for references to my point seems to be illuded by a media blackout as usual..)
A man was suspected of drowning around the harvest moon back in 2009 in Cork. Both the navy divers, coast guard and fire brigade were searching for the body downstream of Cork city. They had requested to reduce the flow of water out of Inniscarra to assist with the search.
Sadly the ESB were stocking up the reservoir leading up to the incident. Coincidentally we had a monsoon of rain that September and levels at the dam were already at their peak, while there was a stong el Nino reported too, hence the wet September.
At 6pm the dam was brimming and it was approaching the remnant high tide from the harvest moon and as high water hit the management let go all of the water at full rate, submerging cork city and adjacent flood areas.
... there really should have been a movie made about it but I believe rte did make a documentary about it a year later

two wheels good

hytrogen wrote: »

OP unfortunately you and the media are completely off the mark with what happened in 2009. (Also searching for references to my point seems to be illuded by a media blackout as usual..)
A man was suspected of drowning around the harvest moon back in 2009 in Cork. Both the navy divers, coast guard and fire brigade were searching for the body downstream of Cork city. They had requested to reduce the flow of water out of Inniscarra to assist with the search.
.......

I too heard that story. I also heard it was untrue that it affected Iniscarra operations. I don't know which is correct.
It would be interesting to know if it was presented as evidence in the court case taken by UCC against the ESB re 2009 flood damage. The ruling of that court case indicated ESB were negligent.

EDIT: PS Nice pun, OP

TheChizler

two wheels good wrote: »

I too heard that story. I also heard it was untrue that it affected Iniscarra operations. I don't know which is correct.
It would be interesting to know if it was presented as evidence in the court case taken by UCC against the ESB re 2009 flood damage. The ruling of that court case indicated ESB were negligent.

He was a UCC student in my course a few years behind me, I presume the search was mentioned in the court case but not publicised for the sake of family and friends.

hytrogen

two wheels good wrote: »

I too heard that story. I also heard it was untrue that it affected Iniscarra operations. I don't know which is correct.
It would be interesting to know if it was presented as evidence in the court case taken by UCC against the ESB re 2009 flood damage. The ruling of that court case indicated ESB were negligent.

I would expect for liabilities the media probably pulled the story or were told to pull the story as the case proceeded for respect of the bereaved.

It seems like the last few years they started to get the managment correct with little or no major flooding around the main systems and suddenly this year there's complete incompetence running the show now.. typical

Impetus

hytrogen wrote: »

OP unfortunately you and the media are completely off the mark with what happened in 2009. (Also searching for references to my point seems to be illuded by a media blackout as usual..)
A man was suspected of drowning around the harvest moon back in 2009 in Cork. Both the navy divers, coast guard and fire brigade were searching for the body downstream of Cork city. They had requested to reduce the flow of water out of Inniscarra to assist with the search.
Sadly the ESB were stocking up the reservoir leading up to the incident. Coincidentally we had a monsoon of rain that September and levels at the dam were already at their peak, while there was a stong el Nino reported too, hence the wet September.
At 6pm the dam was brimming and it was approaching the remnant high tide from the harvest moon and as high water hit the management let go all of the water at full rate, submerging cork city and adjacent flood areas.
... there really should have been a movie made about it but I believe rte did make a documentary about it a year later

I respect that issue. However it took a whole week from memory of water being held back to find somebody who probably was well downstream by then. One person or a few thousand souls at risk of future death or property wipe-out etc? Priorities please.

Impetus

High tide was 3.7m at 11h17 this morning. I was walking along the North Mall at the time, and the river height was about at it's maximum safe height.

The river height maxed out at 4.39m at the Maltings around the same time (http://77.74.50.157/cfw/).

This makes me think that the note on this page that suggested that a reading of 5m or above was a problem level, overstates the safe, day to day maximum level for sluice gate manipulation. 4.5m would be more like a maximum safe level. And of course this visual assessment only applies to the North Mall segment of the river bank.

Impetus

Markcheese wrote: »

The bride valley is a totally different shape to the lee valley . Its mainly wide and flat (from crookstown to the lee anyway, so its flooding and the effect is very different ...

Precisely. Which is why we need river level gauges for various points in the city centre, (basic use for internet of things etc) to manage the River Lee flow in relation to rainfall, all over the region. The current number of monitoring points is appallingly inadequate, and badly positioned in relation to the value at risk (including human life). These data should be available in real time to everybody.

Markcheese

The heavy rain of 2009 may have been forecast in advance - the cloud burst in the caha mountains wasnt anticipated by esb... there were cockups in relation to esb and weather forecasts- esb used to calculate the speed of fill of the lee reservoirs based on rainfall levels at inniscarra... unfortunatly the rainfall levels in the upper levels of the lee catchments were substantially higher....

two wheels good

hytrogen wrote: »

I would expect for liabilities the media probably pulled the story or were told to pull the story as the case proceeded for respect of the bereaved.

It seems like the last few years they started to get the managment correct with little or no major flooding around the main systems and suddenly this year there's complete incompetence running the show now.. typical

Sorry, but this is bizarre. A newspaper can report the facts of a story or any statements made an organisation e.g.the ESB, or the evidence presented in a public court case without concerns about liabilities.

A ~€100m court case is unlikely to skirt the tragedy of a family bereavement simply for "respect for the bereaved". The details can still be handles with sensitivity.
If this story was a factor in the management of water levels I would expect the ESB legal team to have included it in the case content. Whether it would have reduced their liablility is another question.

Impetus

two wheels good wrote: »

Sorry, but this is bizarre. A newspaper can report the facts of a story or any statements made an organisation e.g.the ESB, or the evidence presented in a public court case without concerns about liabilities.

A ~€100m court case is unlikely to skirt the tragedy of a family bereavement simply for "respect for the bereaved". The details can still be handles with sensitivity.
If this story was a factor in the management of water levels I would expect the ESB legal team to have included it in the case content. Whether it would have reduced their liablility is another question.

Yes. And perhaps "out of respect for the family" etc..... the people who live in low lying areas of the city, and their rights not to have their premises flooded, to walk the streets freely, etc were ignored?

Impetus

http://77.74.50.157/cfw/


The river height chart linked to above, shows the water level falling every day to 2.6 m or so.

In times of high rainfall, and/or high forecast rainfall, the opening of Iniscarra Sluice gates should cause this chart to be almost a straight line between 4 and 4.4 m. This chart, and ideally others at various critical points, should be the drivers for sluice gate management. Letting it go down to 2.6 and thereabouts is a waste of water drainage opportunity.

When the weather is wet, there is no shortage of water to keep the turbines running. There is therefore no point in collecting large amounts of water in the reservoir, which is putting the city centre at risk.

Markcheese

Great info ... but if the lee is at flood level from the lee fields to inniscarra ( and it is) releasing extra water to coincide with low tide WILL mean flooding (just not in the city) ,regardless of what a water level meter at the lee maltings(tidal area) says ...

I'm looking at water levels in the harbour at the moment - they could go a lot higher - of course for them to be high (at low tide) from river water you'd have to blow the dam -wiping out ballincolig and the city passage west ect ect in the process.....

hytrogen

So as of yesterday the Straight road is closed from B'collig east roundabout all the way to town, Anglers rest and Iniscarra bridge by the Gun powder mills are flooded, and my sources near the dam say that levels reached as high as they were in 2009 last night due to the sheer amount of rainfall on Tueaday dispite them releasing more than 250MT/s all day yesterday so we could be in for another one perhaps..

Impetus

hytrogen wrote: »

So as of yesterday the Straight road is closed from B'collig east roundabout all the way to town, Anglers rest and Iniscarra bridge by the Gun powder mills are flooded, and my sources near the dam say that levels reached as high as they were in 2009 last night due to the sheer amount of rainfall on Tueaday dispite them releasing more than 250MT/s all day yesterday so we could be in for another one perhaps..

This volume of water should be stored upstream - not causing the N22 to be closed, or worse still flooding the city centre. It would be far cheaper for 'the river management agency' to pay a fee to landowners who have land surrounding Inniscarra and other reservoirs, for temporary right to flood part of their land.

This combined with a series of 'gates' (ie sluice gates, flood gates, call it what you like) could be used to keep overflowing waters where they will cause minimal damage. The land-owner could continue to use the land when there is no 'super-flooding'.

This measure could be supplemented by a system of flood gates at the point where the Lee splits into two channels - allowing the flow rate into each channel to be separately managed. The south channel is much smaller than the north channel - around UCC one could jump across the south channel - an impossible feat over the north channel. This would allow a greatly increased rate of water dumping to take place when large rainfall is forecast while the tide is out - making maximum use of the carrying capacity of the north channel. During periods of heavy tide, the river could effectively be almost totally shut off during the hour or so of peak tide. This would allow the sea water to flow far more inland than if it has a strong river pushing in the opposite direction.

I was just reading this website on cutter suction dredging - published by the company that did the Palm Islands in Dubai. http://www.vanoord.com/activities/cutter-suction-dredger The Rivers Lee and Shannon could benefit from this dredging technique to make the river banks deeper so that they can carry more water and keep the tide at a lower level.

I remember some decades ago when Dutch dredgers reclaimed land around the Tivoli docks in Cork. They used the dredged up silt and sand to create the new land, which is used today for warehouses and factories.

Markcheese

Thats canalisation - aint cheap - and the exact opposite of letting the river food at certain points-
And apart from the balls up by the esb in 09 is it really worth doing ....

hytrogen

What they should really be considering for the Lee is fixing the wier at the gun powder mills, reinstating the canals around that parkland, building dykes (or incentivising the home owners on the banks and flood plains to invest in dyke construction) and dredging the middle course stream areas, possibly to a safe navigable depth for leisure craft or small commercial craft while adhering to the bathing water quality management legislation. That goes for the Shannon too, it's navigable but I wouldn't go swimming there any more

Markcheese

What would reinstating the weir and fixing up the canals do ?? ( I thought the weir was still there ?? )

Impetus

Markcheese wrote: »

Thats canalisation - aint cheap - and the exact opposite of letting the river food at certain points-
And apart from the balls up by the esb in 09 is it really worth doing ....

I have subsequently looked at detailed satellite imagery of the series of reservoirs and dams already in place on the Lee. It seems to me that most of the hardware is already in place. The upstream dams already exist to hold water back, at points where it will do the least damage. Let fields flood around the reservoir, and pay farmers for the use of their probably already soggy field in the middle of winter. I spoke to a farmer (who is not located near this river system) and his view as a farmer was that they would welcome the income opportunity, which would come at little cost to them.

All you need to add is:

1) detailed feedback from river height gauges along both channels of the river, and the reservoirs themselves.

2) A legal and financial provision to engage with farmers and provide for the controlled field flooding.

3) Pro-active reduction in river levels using 10 day rainfall forecasts to maximise reservoir space to store the new rainfall. The limiting factor here is a weir which causes an imbalance of water to gravitate towards the skinny South channel rather than the higher capacity North channel. During the hour or so of high tide during heavy rainfall, simply shut off the river flow from entering the city.

Flooding by the river Lee is caused by river management incompetence, which goes up the line to political incompetence. If this was the Netherlands, there would be no flooding in this area, because the Dutch take the issue far more seriously.

If new hardware is required, it will probably be a form of floodgate for the North and South channels located just West of Wellington Bridge (R846).

Impetus

Markcheese wrote: »

What would reinstating the weir and fixing up the canals do ?? ( I thought the weir was still there ?? )

One of the weirs is actually forcing water into the low capacity South channel. If anything, that weir needs to be partially broken to cause less water to flow into the South channel, and instead use the North channel. No reinstatement of any of the weirs is required. It is a matter of removing the blockages.

Impetus

There is an open source modelling software program called Kalypso, downloadable free from SourceForge. It has six modules:

• Kalypso Hydrology (rainfall-runoff simulation)
• Kalypso WSPM (one-dimensional steady hydrodynamic simulation)
• Kalypso 1D/2D (coupled one- and two-dimensional unsteady hydrodynamic simulation)
• Kalypso Flood (flood mapping tool)
• Kalypso Risk (flood risk assessment tool)
• Kalypso Evacuation (evacuation strategy tool)

It was developed in association with Hamburg University of Technology.

Descriptive article taken from GeoInformatics magazine: http://www.bjoernsen.de/uploads/media/geoinformatics_2009.pdf

http://kalypso.bjoernsen.de/index.php?id=382&L=1

Download link: http://sourceforge.net/projects/kalypso/

It is a mature product, current version 15.1.1

Impetus

EU directive 2007/60/EC requires the government to make flood risk assessments (article 4) , and Article 7 of the directive requires a flood risk management plan to be prepared.

In the case of the River Lee, I see no evidence that the government has complied with this directive. I have no doubt but that the Shannon has similarly been neglected by the State.

http://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32007L0060&from=EN

Markcheese

Impetus wrote:

One of the weirs is actually forcing water into the low capacity South channel. If anything, that weir needs to be partially broken to cause less water to flow into the South channel, and instead use the North channel. No reinstatement of any of the weirs is required. It is a matter of removing the blockages.

Sorry ,crossed wires there was referring to hytrogens comments on the ballincolig/ powder mills weir ...
The more control over river flow that the esb / county council / city council have the better.... bbuuuuttttt the more scope for balls up there is ....there'd have to be a combined river lee commission (probably including port of cork ) and if someone is asleep at the wheel during a flood ( as in 09 ) disaster beckons ...

hytrogen

Markcheese wrote: »

What would reinstating the weir and fixing up the canals do ?? ( I thought the weir was still there ?? )

The wier was damaged in the 2009 floods, costed at over €1m to repair and as a result the canals in the regional drained. They are a nice setting but also could be reassigned to a flood relief support mechanism as well as a navigable tourist attraction to repay the costs of investment.

Impetus

Markcheese wrote: »

The more control over river flow that the esb / county council / city council have the better.... bbuuuuttttt the more scope for balls up there is ....there'd have to be a combined river lee commission (probably including port of cork ) and if someone is asleep at the wheel during a flood ( as in 09 ) disaster beckons ...

It smells like a 'committee' (ESB, County and City councils, port of Cork) rather than any one individual taking responsibility and making decisions. If every business was run that way, the world would be as poor and dysfunctional as the worst off state in Africa.

Whoever is sleeping at the wheel was allowing the river level to go below 2.8m at the Maltings reference point up to low tide (PM) on 30.12.2015. Since then they have not left it fall below 3.4m, with the exception of New Year's night when somebody was back on the Champagne, and the river level was allowed to fall to 3.2m. The reduction in minimum river level allowed the discharge of larger quantities of water. But that did not happen until the N22 and Lee Road were both flooded.

http://77.74.50.157/cfw/

The basic physical resources are present. All it needs is management of the river system that is not asleep, clear responsibility to an accountable person, and high resolution data on water levels with multiple sensors and access to 10 day rainfall forecasts, and the authority to tell the ESB or any other power generator when they can open and close their sluice gates.

It is no different to the poorly configured traffic light management system. Every road user with anything between their ears can see all the wasted junction time by needlessly prolonged red lights. Phase times should be driven by traffic movements, or better still no phase times and the control system just reacts second by second, based on an algorithm. Pedestrian crossing phases operating, when nobody is crossing, can reduce junction capacity by 25% or so. River flooding and traffic management are very similar concepts. As are traffic accident management policies. In Ireland, if there is an accident on a busy road (eg M50, N7 etc), everything grinds to a halt for several hours. In other parts of Europe a cop is dispatched on a motorbike, with a can of fluorescent yellow spray paint so he can spray the road to mark the position of the evidence (vehicles etc). The cars are then moved to a safe place and the traffic continues to flow.

Ireland suffers from 'government' by rigor mortis.

Markcheese

To be fair the carrigrohane staight and lee road flooding for a few days - meh -(as long the houses in the area are ok )
If you increase the flow from the dam above river bank level , it's a flood..
I don't doubt that the flow levels could be managed a lot better (hopefully without a quango) --but to be fair the lee hasnt done much damage in these floods.. to date..

Impetus

Markcheese wrote: »

To be fair the carrigrohane staight and lee road flooding for a few days - meh -(as long the houses in the area are ok )
If you increase the flow from the dam above river bank level , it's a flood..
I don't doubt that the flow levels could be managed a lot better (hopefully without a quango) --but to be fair the lee hasnt done much damage in these floods.. to date..

The Lee fields are a flood plain. Better to flood upstream and store the rainfall, releasing it as fast as the river system can handle it.

A chain of priorities

1. Avoid city centre flooding (a last resort, as was abused in 2009)
2. Avoid Lee fields flooding beyond the grass area
3. Avoid excess water levels above 90% capacity in the most upstream reservoir.
4. Avoid/minimise the need to rent flood land from land owners.

The system should be engineered to reduce the risk of damage to the city with 99.999% chance of success. The reservoirs only have a storage capacity of about 45 million m3 of water, leaving little margin for error. Renting floodable land from land owners could increase the capacity to 60 million m3 or so.

There is a draft flood risk study on the internet - ie it is only a talking document with no sign-off on how to fix the issue. It refers to a cost of 100 € million for a combined river and sea flooding protection as 'may be prohibitive'. The 2009 floods cost €244 million for Cork and the Shannon region - and the Cork element of this is at a guess around 200 million €.

The report talks about putting a tidal barrier from Monkstown to Great Island, and how this would make the other sea flood protection measures redundant. The report mentions this in the context of Cork city and Midleton. It seems to me that Midleton would remain at sea flood risk because of the second channel between East Ferry and the Great Island.

One has to ask oneself what planet do the people who wrote this draft flood management proposal live on? These floods repeat themselves every few years.

http://www.lee.cfram.com/downloads/documents/REP005_draftFRMP.pdf

(This document does not comply with the EU directive, as it is only in draft form - since 2010. There is no evidence of any plan of action to mitigate the issue. It is no different to a prototype car - it might look good, but you can't go to your local dealer and buy one. The document talks about setting up a virtual talking shop (my words) at leecframs.ie - this URL has no website of its own in 2015, instead it points to the OPW website - the most incompetent, bureaucratic organization in Europe)

Impetus

An article on flooding in today's Irish Times puts a large part of the reason down to a lack of local democracy.

'As flooding gets worse, we will have to spend enormous amounts of money on engineering solutions. But in fact one part of the solution doesn’t cost any money at all. It’s called listening. Or, to give it its political title, it’s called genuine local democracy. Top-down, very expensive technocratic measures may have to be part of the response. But they will only work in a political culture that has eyes to look at the land and ears to listen to what people know about it. '

More:
http://www.irishtimes.com/opinion/fintan-o-toole-genuine-local-democracy-part-of-the-solution-to-flooding-1.2484701

hytrogen

http://www.irishtimes.com/news/ireland/irish-news/former-canals-may-be-useful-in-alleviating-future-flooding-1.2484961

A perhaps unpopular suggestion due to the costs but as the locals suggest every millimeter counts. What Colin Becker may not be quoted on or mentioning is the economic opportunity through tourism and trade of extending the navigation through these derelict parts that could be recouped.