Ireland has more than 12,000 lakes. Lough Corrib is the largest lake in the Republic of Ireland and contains around 800 billion litres of water, enough to fill more than 300,000 Olympic-sized swimming pools.
Lakes and reservoirs are the main source of drinking water for two million people in Ireland.
The Environmental Protection Agency currently reports on the ecological health of over 200 lakes. This information helps us understand and manage this freshwater resource.
Lake water quality in Ireland is better than the European average, but there is no room for complacency as more than half of our monitored lakes are failing to meet their environmental objectives to achieve good ecological status or maintain good ecological status or higher if it already exists.
What is monitored?
Each lake is monitored for a range of different plants and animals, including:
- phytoplankton (tiny, free-floating plants)
- diatoms (type of algae)
- aquatic plants
- fish (monitored by Inland Fisheries Ireland)
The lakes are also monitored for chemical and physical parameters. The chemical and physical parameters measured include:
- nutrients such as nitrogen and phosphorus
- dissolved oxygen
- water clarity
The plants and animals are monitored once every three years while the physical and chemical parameters are measured several times a year. Changes are also recorded like:
- any change in the physical structure of the lake shore
- changes in lake water level
- changes in how much water is flowing in to or out of the lake