Aquatic ecology survey of ESB Reservoir

We have just commenced a major aquatic ecology survey of Carrigadrohid Reservoir (5.3km2) in Co Cork. This reservoir is located upstream of Carrigadrohid dam, which is the second ESB dam upstream on the River Lee. It was constructed as part of the Lee Hydroelectric scheme (1952 to 1957). Our survey will inform the future management of water levels in this artificial lake, and will include detailed surveys of the plants, macroinvertebrates, fish and physical habitats at sites located around the entire reservoir.

Surveys like the one we are currently undertaking will inform sustainable management plans for this reservoir in the future

Here is a selection of photos from our fieldwork this week when we were selecting suitable index sites around the reservoir which will be subject to detailed assessments, including shoreline electrical fishing, sweep sampling for littoral macroinvertebrates and aquatic plant surveys. We will provide updates of these surveys on our Facebook page, and also on the news section of our main website.

The Gearagh

The Gearagh, or ‘An Ghaoraidh’ meaning “wooded river”, was one of the most important of Ireland’s ancient woodlands, and the only extensive alluvial forest found in Europe west of the Rhine. However in 1954/55 extensive clear felling was undertaken and the eastern side of the forest was flooded to facilitate the installation of the upper part of the Lee hydro-electric scheme. Around 60% of the former woodland was lost, and now forms part of Carriadrohid Reservoir.

The alluvial woodland which remains today in the Gearagh today is still of unique scientific interest, and is a designated Special Area of Conservation, a Ramsar site and a Biogenetic Reserve. Indeed, the remnants still actually represent the only extensive alluvial forest west of the Rhine in Europe. Surveys like the one we are currently undertaking will inform sustainable management plans for this reservoir in the future.

ESB’s Carrigadrohid dam is the upper dam on the River Lee. Iniscarra dam is located downstream from here and both dams flooded the Lee Valley in the 1950s.
ESB’s Carrigadrohid dam is the upper dam on the River Lee. Iniscarra dam is located downstream from here and both dams flooded the Lee Valley in the 1950s.
Aerial photo of the Gearagh, which was flooded by the construction of Carrigadrohid Reservoir by the ESB in the 1950’s.
Aerial photo of the Gearagh as it is today, with the extent of the area lost as as a result of the construction of Carrigadrohid Reservoir in the 1950’s apparent.
The western end of Carrigadrohid reservoir showing the tree trunks of the ancient Gearagh alluvial forest which was felled and flooded by the ESB in the 1950s.
The western end of Carrigadrohid reservoir showing the tree trunks of the ancient Gearagh alluvial forest which was felled and flooded by the ESB in the 1950s.

Further information

If you require any further information about the freshwater ecology survey work we do or how we can assist you with a project, please do not hesitate to contact us. Also, some of our recent posts on our main website are as follows:-

Also subscribe to ECOFACT NEWSDESK to receive regular updates on our work and important news stories concerning ecology in Ireland.

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