Much of the west bank of the Shannon, northwards from Portumna to Meelick, is embanked. The purpose of the embankments is
[…] to permit higher operating levels in Lough Derg wuthout flooding low lying land along the right bank of the river. They also serve as flood protection against storm floods. (E Conaty and M Long “Long term behaviour of Portumna embankments” in Paul Tedd, ed, Reservoirs in a changing world: proceedings of a conference organised by the British Dam Society, Thomas Telford Publishing, London, 2002)
According to the Heritage Council’s Waterways Corridor Study 2006: a study of the area surrounding the Lower Shannon navigation, including Lough Derg, from Meelick, Co Galway to Limerick City:
Three pump stations along the western shoreline drain water from the low-lying lands adjacent into the river.
I have spotted only two myself, but Colin Becker kindly told me where the upstream station is. The pumping stations featured in the Irish Times in November 2009.
The upstream pumping station
The upstream station is to the west below Meelick Lock.
The middle pumping station
The middle station is here, and shown on a Google satellite photo here.
How to find the middle pumping station
This is the electric cable crossing the Shannon at the north end of Sally Island.
Incidentally, you may wish to know the clearance under the ESB’s electricity cables. Well, I’m sorry, but it won’t tell you. If it did, and you touched one with a mast, you might sue and the ESB might lose money. So it’s better that you should be fried to a crisp by risking using too high a mast than that you should have the information that would enable you to make a rational decision. I spent much time trying to get answers from ESB about the clearances but got absolutely nowhere. If you are from ESB and would like to prove me wrong by providing the information, please leave a Comment below and I’ll get in touch with you.
Dont climb it!
The pumping station
Pumping station, navigation mark, west-bank pylon
Broadside on
A Calnan unit
A Calnan unit could be pretty well anything: perhaps even a waterways bog!
What is the steel framework for?
The downstream pumping station
The downstream station is here, and shown on a Google satellite photo here.
How to find the downstream station (from upstream)
This station has two buildings.
Another blue box: what joy!
The little grey workboat
There’s a close-up of the workboat on this page.
The second building
The second building is narrower than its upstream counterpart. It has another of those steel frameworks.
Irish waterways history 
The steel frameworks look like cranes. From the photos, they look like they are waterside as well, which would allow for delivery of equipment by water to be hoisted onto land.
True. And ESB has a little workboat that is often seen nearby. bjg
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