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Water Quality

Loughs Agency annually carries out biological and chemical sampling at more than 100 freshwater sites in the Foyle and Carlingford catchments.Pollution monitoring has several key objectives:

  • Identify potential threats to fish health and aquatic ecosystems
  • Inform the public about the quality of the aquatic environment and raise public awareness of environmental issues
  • Contribute to policy-making decisions
  • Measure the effectiveness of pollution control measures
  • iIentify trends in pollution and anticipate future problems.

Sampling usually takes place from June to September. Each site is tested monthly, giving us four chemical samples for each location. Our Water Sampling Officers use probes to measure dissolved oxygen levels and to gather conductivity, temperature and pH (acidity) readings.

The findings can tell us a great deal about the quality of our waters. Low levels of dissolved oxygen are often linked to fish kills while optimum levels can result in good growth. Significant increases in conductivity may be a sign of pollution.

River temperatures are critical. Fish can become stressed if the water gets too warm and this can affect spawning. If the pH reading is too high or too low, the organisms living in the water may become stressed and even die.

Samples are sent to our laboratory for analysis. The various chemical tests can help identify rivers that are under pressure from pollution from a variety of sources, such as agriculture, forestry, urban wastewater and construction.

Biological and chemical test results are combined with electrofishing and habitat data to identify rivers that could benefit from enhancement work. This allows us to target resources quite precisely, with positive results for fisheries, habitat and water quality.

Our proactive monitoring, testing and enhancement measures ensure that potential threats to fish health or aquatic ecosystems are detected and addressed.

Her Majesty Queen Elizabeth II

21 April 1926 to 8 September 2022