Tag Archives: floods

Down to the sea in steps

On 28 January 1907 James Robinson Kilroe [near the bottom of the page] of H M Geological Survey read to the Royal Irish Academy a paper on “The River Shannon: its present course and geological history” [Proceedings of the Royal Irish Academy Vol XXVI Section B No 8 Hodges, Figgis & Co Ltd, Dublin; Williams & Norgate, London 1907]. I thought that Plate V was interesting.

Shannon Derg to sea

Plate V

Kilroe wrote:

It will be perceived that instead of the river being shallow over the unyielding Silurian slate-rock, set almost vertically, and striking across the river-course, it is deeper than over the limestone of Lough Derg, and much deeper than over the comparatively easily eroded Old Red Sandstone at Killaloe. The river-bed actually drops below the datum line above the town, while at the town it is 100 feet above datum.

Old Red Sandstone strata are here to be seen in the river-bank, and Silurian rocks in situ in its bed. A barrier is thus formed, partly of Silurian, and partly of Old Red Sandstone rocks, which without the artificial impounding weir would retain the waters of Lough Derg to a depth of some 104 feet opposite Derrycastle — two miles above Killaloe.

One might have expected to find a fairly level shallow bed from Killaloe northward, a sudden drop from slate-rock to the sandstone floor, and  a pronounced wide, well-formed valley in the limestone district southward to Limerick.

None of these elements exist; instead, we have the formidable barrier at Killaloe, naturally damming up a considerable depth of water in Lough Derg, and the river falling away southward by a series of rapids which correspond with drops in the canal, south of O’Briensbridge […], along an alternative course, possibly one used by a branch of the Shannon.

Here is an extract from the Plate V map, showing the steps of the (pre-Ardnacrusha) Limerick Navigation between Lough Derg and the sea.

Shannon Killaloe to Limerick

The steps of the canal (click to enlarge)

Upstream

Kilroe wrote of Lough Ree:

The waters of Lough Ree stood some 10 feet higher within recent times than they now do, as proved by evidence of solution, with under-cutting of limestone blocks, to be seen about five miles north-west of Athlone, close to the railway, in the townland of Cornaseer.

Under these conditions the lake must have been, perhaps, twice its width, and for a considerable period. Its ancient surface-level is clearly indicated by the caps of the mushroom-shaped blocks.

And of the Shannon between Lough Ree and Lough Derg:

The extreme flatness of the river between Athlone and Meelick is such that, consequent upon the completion of the Suck Drainage-works in 1892, it was found that the callows along the Shannon above the confluence of the Suck at Shannonbridge were much more liable to sudden and frequent floodings than they previously had been.

The more rapid discharge of the Suck waters into the Shannon, before ordinary extra water had time to pass away, had the effect of modifying the regimen of the main stream to an extent which resulted in an action at law [La Touche -v- The Suck Drainage Board].

I have found only one account of that case, in the Freeman’s Journal of 1 July 1893. The plaintiffs, Messrs Harrison and La Touche, owned land at Cappaleitrim, on the west bank of the Shannon above Shannonbridge. They said that the actions of the Suck Drainage Board had caused their lands to be flooded:

[…] that the defendants brought water from the Suck into the Shannon, containing a drainage of 40 miles, with such velocity and such volume that the Shannon was penned back, and that the back water caused the damage to the lands complained of.

[…] The jury disagreed and were discharged.

I don’t know whether the matter ever again came before a judge.

Royal Canal water supply

On 26 November 2012 I noted that

The Royal Canal water supply applications have been approved by An Bord Pleanala. There were two separate applications […] but they were in effect treated as one.

There were conditions attached, but I concluded that

If I remember correctly, the amount of water available from Lough Ennell will not always provide enough (eg in a dry season) to keep the canal full. Still, this is a significant advance for Waterways Ireland and for Royal Canal enthusiasts.

So here we are, almost two years later, and the work of providing a supply from Lough Ennell to the Royal Canal, reckoned to be about a five-month job, has doubtless been long completed, no?

No.

The work has not yet started and Waterways Ireland will be lucky if it gets done within the next year.

As I understand it — and if, Gentle Reader, you have more information, do please leave a Comment below (your name can be kept out of public view if you like) — there are three sources of delay:

  • first, I understand that there is a technical issue about one of the conditions attached to the approval; it is felt that the condition is unworkable, but that getting it changed might take some time. I presume it’s one of the conditions 2(a) to 2(d) that I quoted two years ago and, looking at the proposed orders published in the press [PDF], I suspect it might be the requirement to maintain the lake level at or above 79.325 mOD Malin Datum. However, I don’t really know
  • second, Waterways Ireland took over Clonsingle Weir, at the outlet from Lough Ennell, by Compulsory Purchase. Owners of mills, who generate electricity from the Brosna, have submitted claims for compensation. I understand that an arbitration hearing, lasting four days, is scheduled to be help in May 2015
  • third, responsibility for the scheme has moved from Westmeath County Council to Irish Water. Which may have other things on its mind.

Irish Water has published its proposed Capital Investment Programme [PDF] but Appendix 1, the Investment Plan Project Summary, is in a separate file [PDF]. Category B is headed Review Scope and Commence Construction and it includes

Mullingar Regional Water Supply Scheme (G) … Lough Ennell Abstraction.

I can’t work out what “(G)” means. A few items are so marked; a few others are marked “(H)”; most items have neither.

The Capital Investment Programme [CIP] document says:

 The CIP is dominated by contractual commitments entered into previously by Local Authorities, and which have now transitioned to Irish Water. In the 2014-2016 period, Irish Water will fund these contracts to completion and bring forward programmes and prioritised projects to commence. At the same time, it will progress a large portfolio of projects that are at the planning and design stage, reviewing their scope, budgets and, where appropriate, timing to favour maximising the performance of the existing assets through intensified capital maintenance that might allow deferral of major capital investment.

Emphasis mine. So that raises the possibility that Irish Water will decide not to fund the abstraction scheme but will rather opt to pay for continued pumping.

It is, of course, quite possible that I have misunderstood these difficult matters, so I will be glad to hear from anyone with better information.

Incidentally, reviewing Irish Water’s documents suggests to me that there are people there who know what they are doing and who have the expertise to manage large and complex operations. That differentiates them from the politicians in government and opposition, few of whom (as far as I can see) have any experience of running anything more complex than a parish social.

 

 

Steam, the Shannon and the Great British Breakfast

That is the title of the Railway and Canal Historical Society‘s 2014 Clinker Memorial Lecture, to be held at the Birmingham and Midland Institute, Margaret Street, Birmingham B3 3BS, at 1415 on Saturday 18 October 2014.

The lecture will concentrate on the period before 1850 with such interesting topics as

  • Shannon steamers
  • the Grand and Royal Canals
  • the first Irish turf (peat) to reach the USA (possibly)
  • port developments in Dublin, Limerick and Kingstonw
  • the Dublin and Kingstown Ship Canal
  • the Midland Great Western Railway
  • what “cattle class” really means
  • bacon and eggs.

Admission is free and booking is not required. However, if you plan to attend, it would be helpful if you could e-mail […] to this effect.

The Clinker Memorial Lecture is named for Charles R Clinker, an eminent railway authoe and one-time historian of the Great Western Railway, who died in 1983.

If you would like the contact email address, leave a Comment below and I’ll get in touch with you direct.

 

 

The monsoon is coming …

… perhaps. The water depth at Banagher has stayed at around 2.1 metres but that at Athlone has gone down to about 2.0 metres. Are TPTB lowering Lough Ree so that it can store the water from the autumnal rains? Information welcome.

Construction

The government’s new election manifesto construction strategy has just been published and can be downloaded here. I wouldn’t bother, though: there’s nothing in it about the Clones Sheugh and it’s written in the sort of turgid prose that won’t fry your brain: it will instead submerge your brain in a slurry pit and hold it under, providing a slow, choking, unpleasant death.

Anyway, the doughty Rob Kitchin has waded through it on our behalf and gives his conclusions here. I don’t share his enthusiasm for National Spatial Strategies and National Development Plans, but I have some sympathy for him when he says

I would have preferred something a bit more holistic, rather than trying to frame a whole bunch of stuff as a coordinated plan.

Michael Hennigan uses the B word.

The Shannon in winter

Waterways Ireland has kindly supplied me with the Shannon traffic figures for January and February 2014. The usual caveats apply. I have not made any charts because the traffic levels were so low:

  • in January, nineteen boats were recorded; of them, ten went through Portumna Bridge. Thirteen boats were private and six hired
  • in February, thirteen boats were recorded, five of them at Portumna; nine were private and four hired.

The total of 32 boats in the two months is extremely low. Since 2003, the Jan–Feb totals have been:

2003   45
2004 112
2005  67
2006  92
2007 127
2008  72
2009 124
2010  72
2011 114
2012  94
2013  97
2014  32

As Waterways Ireland intends to “prioritise navigation opening times to the times of greatest use, in order to achieve maximum use of resources available”, we may expect the Shannon to be closed in winter.

 

Flood plains

Patrick O’Donovan [FG, Limerick] wants to drain the Shannon. Or wants farmers to do it. He doesn’t want the “multiplicity of agencies [which] have made it virtually impossible for anything to be done with the river and the rivers and streams draining into it”; he wants a non-multiplicity of agencies — “the OPW, the Department of the Environment, Community and Local Government, Inland Fisheries Ireland or whoever” — to dig sheughs and stop flood plains flooding. He says

The one group of people who seem to have no say are those who live on the banks of the rivers or who have watched thousands of gallons of water coming in their front door and out their back door.

But he is wrong. That is the one group of people who can stop flood waters coursing through their houses and who can do it most quickly, most easily and without the permission of a single state agency.

The solution is simple: they should move house, away from the flood plains to higher ground.

Lowering Lough Derg

Boat-owners concerned about high water levels on Lough Derg will be glad to know that relief is in sight, although it may take a little while to arrive. Irish Water has taken over the project to send Shannon water to Dublin and is procuring something, although it is not at all clear what that is. The, er, news item is so far leading in the competition for least informative press release of the year.

Big it up for the OPW

I’ve just been reading some particularly nitwitted Dáil discussions and I need some time to calm down enough to report on them to the Learned Readers of this site. Let me just say that anyone who thinks that politicians cannot distinguish fact from fiction is absolutely right. But enough of that for the moment.

I reported earlier on an oddity in the results from the OPW’s Athlone waterlevel gauge. I emailed the OPW about it and a helpful chap got back on more or less immediately.

He explained that the data we see on the waterlevel.ie site is, as it were, live: raw unfiltered data with nothing added, nothing taken away. The same data goes in to the OPW and they spotted that the Athlone gauge was reading too high. They found the sensor was faulty; they have now adjusted it and the new, lower readings are correct.

The disappearance of the placenames is because of some work in progress on improving the website; they will be back.

He kindly pointed me to a list, in .xlsm format, downloadable from here; it shows all hydrometric stations in Ireland. It shows who operates them, whether they’re active and whether they use telemetry (which I take to mean that they can be monitored remotely). Unfortunately OPW itself doesn’t seem to have any gauges on Lough Derg and nor does Waterways Ireland. OPW does have a rather excitable gauge at Scarriff and gauges upstream of Meelick Weir and Meelick (Victoria) Lock. The ESB has gauges with telemetry at Ballyvalley (25073) and Killaloe (25074) but I can’t find any website giving the levels. If, Gentle Reader, you can find one, perhaps you would let us know.

The consoling part of dealing with the OPW is that you get the distinct impression that they know some useful stuff. Unlike, say, some folk working in Kildare Street ….

Thump it on the thirteenth

Here is a screenshot from the OPW’s online waterlevel gauge for Athlone Weir. It shows the levels for the past 35 days. In recent days the waterlevel website has ceased to show the names or locations of the gauges, but 26333 is Athlone Weir.

Athlone waterlevel: 35 days to 14 February 2014

Athlone waterlevel: 35 days to 14 February 2014

Note the odd discontinuities: the level jumped up on 13 February and fell back on 13 February. Does the gauge get stuck every so often and have to be thumped to free it?

I do not know. I have reported both the discontinuities and the disappearance of the station names to the OPW.