Tag Archives: cumec

ESB water discharge info

Here is the ESB’s Notifications page, with info on the rate of discharge from its hydroelectric dams and weirs. Today (14 December 2015) Parteen Villa Weir is discharging 440 cumecs (cubic metres per second or, roughly, ton[ne]s per second down the original course of the Shannon. That’s 44 times the 10 cumec usually discharged and more than replaces the 400 cumec diverted through the headrace to the Ardnacrusha power station. The Shannon is therefore running at its pre-Ardnacrusha levels and the Falls of Doonass have regained their power.

Of course if Ardnacrusha didn’t exist, its 400 cumec would be coming down the original course of the Shannon on top of the 440 cumec already there, which would make for interesting levels of flooding.

That ESB page has a link to this infographic, which shows the sort of information I was trying to get across here. I usually start from Leitrim [village]; the ESB starts slightly further upstream at Lough Allen. Note that the Shannon’s few locks are concentrated upstream of Lough Ree: between them and Killaloe are only two locks, at Athlone and Meelick, so the river’s fall is very slight.

Update 2018: the ESB has a new page with lots of interesting information here.

What’s a cumec, Daddy?

I don’t know, but here’s a picture of 415 of them flowing through Castleconnell. [Update 13 December: that may be only 405 cumec.]

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415 cumecs on 12 December 2015

Actually, a cumec is one cubic metre of water per second, which is roughly one ton per second, which is a lot of water. And 415 cumec is the amount that, according to the blatts, the ESB is currently letting down the original course of the Shannon from Parteen Villa Weir; the minimum flow in that channel, as seen in summer, is 10 cumec.

Castleconnell 12 December 2015

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Younger trees getting their feet wet

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Who’d have guessed?

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Below the bridge

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Above the bridge

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Stormont

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Pump

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Sandbags

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Sandbag Central

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Sandbags filled here for distribution

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Army engineers

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More equipment arriving

Clonlara 11 December 2015

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Ardnacrusha headrace, said to take 400 cumec

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Errina bridge on the Plassey-Errina Canal

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The stop planks seem to be quite effective …

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… as there is little water getting down the canal to Clonlara bridge

Park Canal 9 December 2015

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Depth gauge at Park Lock

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Lock chamber

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Full canal upstream

 

Shannon water levels 8 December 2015

North to south (more or less)

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Shannonbridge upstream

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Shannonbridge downstream

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Shannon Harbour: 36th lock

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Shannon Harbour: below the 36th

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Shannon Harbour: road to Banagher closed

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Banagher: the harbour above the bridge

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Banagher: the harbour’s sole inhabitant

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Banagher: work goes on

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Portumna Bridge: Hawthorn moving

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Portumna Bridge

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Below Portumna Bridge

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Above Portumna Bridge

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Portumna Bridge: Waterways Ireland yard

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Mountshannon

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Mountshannon: the main quay

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Scarriff: the river in flood

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Scarriff: the river flowing on to the road to the harbour

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Scarriff: sandbags blocking the road …

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… to the Waterways Ireland Shannon HQ. Anyone in the building must have waded there

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Tuamgraney

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Killaloe: the flash lock

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Killaloe bridge from downstream

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O’Briensbridge

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Water level with the quay at O’Briensbridge

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Flooded fields at O’Briensbridge

O’Briensbridge is on the original course of the Shannon, downstream of Parteen Villa Weir, which controls how much water goes via the original course and how much goes to the hydroelectric power station at Ardnacrusha.

Normally, the original course gets the first 10 cubic metres per second (10 cumec, they say) of water and Ardnacrusha gets the next 400, 100 for each of its four turbines. In floods, any excess is sent down the original course, through O’Briensbridge, Castleconnell and Plassey. One newspaper today said that, on Monday 7 December 2015, 315 cumec had been sent down the original course and, on Tuesday 8 December, 375 cumec.

The water levels are still below the peak achieved in November 2009, but there is more to come: as the Shannon drains a very large amount of Ireland, and as it is falls very little in its upper reaches, it takes a long time for the runoff to reach Killaloe and Parteen Villa. It may be that the ESB, which controls Ardnacrusha and Parteen Villa, is now running down the level of Lough Derg to make room for the water that has yet to arrive from the upper Shannon.