River study completed


Last summer we carried out the surveys and eco studies of Ballyhip and Carrowniskey rivers. The study was funded by the Community Waters Programme and carried out by Dr Ross Finlay and Dr Ken Whelan. The key findings of the study are below. If you want to know more, have a look at the summary report or contact us to get a copy of the full report.

KEY FINDINGS – Generally, both systems were found to be in good ecological condition. However, a pattern of declining water quality and ecological conditions was identified as sampling sites were assessed, moving downstream from the headwaters to the lower reaches of each river. Specific issues identified are listed below:

  • Signs of significant point source pollution and associated reductions in ecological condition were identified at survey sites on both rivers. However, only a small number of sites showed signs of severe pollution.
  • There is a general risk of diffuse pollution leading to enrichment of the water courses as well as risks from the use of herbicides/pesticides (e.g., MCPA).
  • Peat extraction and livestock impacts were identified at a number of sites.
  • The waste water treatment plant (WWTP) in Louisburgh has exceeded the plant’s nominal design organic capacity during peak weeks in recent years (2017-2022).
  • Numerous Emission Limit Value breaches have been recorded at the Louisburgh WWTP and significantly increased nutrient levels (ammonia and orthophosphate) have been recorded below the WWTP discharge points.
  • Low flows and high water temperatures are undoubtedly an issue in these catchments, particularly in Roonagh Lough where low oxygen concentrations were also recorded. These issues are likely to increase as climate change is predicted to increase the intensity of summer droughts and heatwaves in the West of Ireland.
  • Water abstraction for domestic and agricultural use may well pose a serious threat to fish passage and in-stream biota during prolonged periods of low flow. Potential increases in abstraction from the Bunowen for the Louisburgh Public Water Supply are of particular concern.
  • Adequate shading is absent from significant sections of the Carrowniskey catchment, particularly where large swathes of marginal vegetation were recently removed from the river bank.
  • A bridge apron attached to one of the Bunleemshough bridges may have the potential to impede the upstream movement of migratory fish, particularly in low water conditions.

Related links:

April 2023 – CALL receives funding to survey local rivers

August 2023 – Event: CALL’s exploring our rivers this Heritage day