pipe with sludge flowing out onto soil and rocks

Threats to Our Waters

With more than 5,000 lakes, 7,000 km of coastline, and a network of rivers and streams crisscrossing the country, Ireland’s waters represent a precious resource in terms of economics, recreation and tourism. However, there has been a steady and serious decline in the quality of this resource over the last thirty years. This is not surprising given the dramatic change in our social and economic circumstances during the same period. Ireland has evolved from a nation of primarily low-impact extensive agriculture to one of increased population, industrialisation and intensive agriculture.

Pressures on Ireland’s waters – Water pollution & physical interference

By far the most serious water pollution problem facing Ireland’s waters today is eutrophication, in which the nutrients nitrogen and phosphorus overload the aquatic environment well beyond natural levels. The main causes of this type of pollution are:

  •  Agriculture: The spreading of slurry and fertilisers on farmland, especially close to water courses, in inappropriate weather conditions or in fields which are already saturated with nutrients, leads to nutrient loss from the land to waterways
  • Urban Waste Water Treatment:  The most recent EPA report on urban waste water treatment (2018) found  that treatment at 21 of the 169 large urban areas in Ireland failed to meet EU standards. Alarmingly these 21 problematic areas produce over half of Ireland’s urban waste water. Additionally, sewage from the equivalent of 77,000 people in 36 towns and villages is released into the environment
    every day without treatment.
  • Faulty and/or poorly sited septic tanks: Leaking of human sewage from the private septic tanks of single houses (not joined up to ‘mains’ sewerage systems) poses a significant risk to water quality and human health. Tanks which are sited on unsuitable soil, or which are not emptied and maintained regularly, result in effluent which either runs into nearby streams or down into groundwater.

Other pressures on our rivers, lakes and bays include:

What is Eutrophication?

Eutrophication is the over-loading of the aquatic environment, beyond natural levels, with the nutrients nitrogen and phosphorous. This process leads to changes in the physical, chemical and biological nature of the water body, and to a disruption of the delicate ecological balance in the water.  Excess nutrients promote excessive plant growth, resulting in a green ‘cloudiness’ to the water, lots of slimy green algae coating the stones and rocks at the edge and bed of the watercourse (‘algal blooms’), or an overgrowth of larger plant life. This in turn leads to a depletion of the oxygen that is naturally dissolved in water, and which fish and other animals need to live. In extreme cases of the ‘deoxygenation’ of a watercourse, serious fish kills can occur.