This publication is categorised as a CSO Frontier Series Output. Particular care must be taken when interpreting the statistics in this release as it may use new methods which are under development and/or data sources which may be incomplete, for example new administrative data sources.
Rivers and lakes covered just over 2% of Ireland in 2018, slightly below the EU average of almost 3%.
Ireland's rivers extended for more than 74,000km.
About 31% of the total length of rivers in Ireland occurred in just three counties – Cork, Donegal and Mayo. There were more than 7,000km of river ecosystems in each of these counties.
Lakes and reservoirs covered more than 128,000 hectares.
About 41% of Ireland’s total lake area occurred in two counties - Galway (23%) and Mayo (18%).
Wicklow was the county with the largest area of reservoirs, at more than 2,000 hectares, while Cork's reservoirs covered more than 1,000 hectares.
Ireland's rivers and lakes host eight Habitats Directive Annex I habitats, including the priority habitat Turloughs, which are temporary lakes that occur in limestone depressions. Annex I habitats are recognised as threatened in the EU territory, and their conservation is of international importance.
This publication is a first look at extent accounts for two ecosystem types – Rivers and canals and Lakes and reservoirs. A future publication will examine condition.
Data from three different sources were used to examine the extent:
CORINE Land Cover – this dataset is somewhat coarse, with a minimum mapping unit of 25 hectares, but allows comparison across EU countries, and there is a time series going back to 1990. For more information, see the chapter on Extent - CORINE Data and Background Notes.
Environmental Protection Agency (EPA) data for Water Framework Directive (WFD) reporting – these are the best available datasets for mapping rivers and lakes at a national level. For more information, see the chapter on Extent - EPA Water Framework Directive Data and Background Notes.
National Parks and Wildlife Service (NPWS) Habitats Directive data – these data estimate the current distribution of specific threatened habitats that occur in rivers and lakes in Ireland. For more information, see the chapter on Extent - Habitats Directive Article 17 Data and Background Notes.
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Statistician's Comment
Statistician in the Ecosystem Accounts Division, Nova Sharkey, commented:
"Rivers and lakes are an integral part of the Irish landscape. They provide us with a range of ecosystem services, including water for drinking, fish for food supply, areas for flood protection, and cultural and recreational services. This Frontier Publication on Rivers and Lakes by Extent looks at where our freshwater aquatic ecosystems are, and how much of them we have.
More than 2% of Ireland was covered by rivers and lakes in 2018, but this figure doesn't fully convey the extent of these ecosystems.
Ireland's network of rivers and canals stretched for more than 74,000km, and are present in every county. About 31% of the total length of Irish rivers was in three counties - Cork, Donegal and Mayo. Each of these counties had more than 7,000km of rivers. Dublin, Longford and Louth had the shortest total length of rivers, at less than 900km in each county.
Lakes covered more than 125,000 hectares, while reservoirs covered more than 3,000 hectares. More than 22% of the area covered by lakes occurred in Galway (28,489 hectares), with almost 18% in Mayo (22,394 hectares). Carlow, Dublin, Kildare, Kilkenny, Laois, and Louth were the counties with the smallest areas covered by lakes, with less than 100 hectares of lake ecosystems in each county. Wicklow had 64% of the country's area of reservoirs (2,224 hectares), while more than 31% of the reservoir area occurred in Cork (1,094 hectares).
Ireland's rivers and lakes host eight Habitats Directive Annex I habitats, including the priority habitat Turloughs. Turloughs are temporary lakes that occur in limestone depressions. They are usually flooded in the winter, (primarily by groundwater), and dry during the summer. Turloughs are important for providing winter-feeding and breeding grounds for some species of waterfowl and wading birds. They are also important for aquatic invertebrates, and for plant species of bare ground.
Annex I habitats are recognised as threatened in the EU territory, and their conservation is of international importance. For more information see the chapter on Habitats Directive Article 17 Data."