The quality of Isle of Man river water has continued to improve with 95% of water courses receiving the best chemical rating, a government report has showed.
Environmental Protection Officers from the Department of Environment, Food and Agriculture (DEFA) use a classification to produce a rating for each site, based on biological, chemical and nutrient data.
When considered together it provides a comprehensive representation of overall river quality and is used to build a long-term picture of the health of Manx rivers and streams.
The chemical status analyses for dissolved oxygen, ammonia and biochemical oxygen demand whereas nutrients is split into nitrate and phosphate. Biological grading assesses the invertebrates which inhabit the riverbed.
The report shows a positive trend, with all 26 monitored sites achieving a biological rating of very good or good over the past three years.
The ratings clearly demonstrate that the percentage of river length achieving ‘very good’ chemical status improved from 88% in 2015 to 95% in 2018 – the highest ever improvement.
Geoffrey Boot, MHK, Minister for DEFA, said:
‘Being an Island nation, water quality is of huge importance. Looking after our water quality in rivers and beaches is crucial to our international reputation and our UNESCO biosphere status.’
‘The report shows an encouraging and positive trend in the right direction.’
Monitoring nutrients in the form of phosphate and nitrate is important as high concentrations can cause increased organic enrichment with excessive plant and algal growths. The main sources of these substances are land run off from agricultural fertiliser, animal excrement and detergent from sewage effluent.
The report shows phosphate levels have decreased over the past 20 years with 95% of watercourses classified as very low and just less than half of the rivers achieved a very low status for nitrate. Further investigations are required to identify the source of the nitrate and then steps will be taken to reduce the concentrations entering our watercourses.
Other studies into the effects of historic mining activity and redundant landfills are also required to further improve the health of our rivers and protect the environment.
The public is asked to play its part in protecting our rivers and reservoirs by reporting any incidents of potential water pollution to the Environmental Protection Unit on +44 1624 685885.