Almost half of Ireland’s rivers have unsatisfactory water quality levels and there was a decline in water quality in 230 rivers recorded in 2020. Nitrogen and phosphorus from agriculture and urban wastewater discharges continue to be the most significant pressures on surface and groundwaters in Ireland, causing a decline in water quality.
The Irish Environmental Protection Agency (EPA) published an indicators report on Wednesday on the quality of water in Ireland's rivers, lakes, transitional and coastal waters and groundwater, using information collected in 2020. The overall water quality improvement reported for 345 rivers of the 1,836 assessed river bodies resulted in a net improvement of 115 rivers. However, the EPA states that declines are negatively offsetting the improvements made.
Mark Horton, All Ireland Director at the Rivers Trust, says: “This report is disappointing reading, bringing into sharp focus the sorry state of rivers and lakes in Ireland. Whilst it’s good that there has been a net improvement of 115 rivers, the overall picture suggests that our precious waterways are declining in health and, without doubt, the precious wildlife that depends on them. Not just this, but our ability to use our rivers for recreation and enjoyment is rapidly diminishing at a time when our local outdoor spaces have become a refuge for us all. The Rivers Trust, we and local Rivers Trusts, are working across Ireland to deliver nature-based solutions, in collaboration with relevant stakeholders, as well as providing practical advice to land managers, to bring about the revival that rivers – and people – desperately need.”
Nitrate levels in rivers, groundwater and estuaries in the south, southeast and east of Ireland are too high, primarily due to agricultural activities through the use of chemical and organic fertilisers. Nearly half (47%) of the river sites have unsatisfactory nitrate concentration and 38% of the sites have rising concentrations. The EPA identified strong indications that these nitrogen inputs are increasing the levels of nutrient pollution in Ireland’s marine environment. Over a fifth of Irish estuarine and coastal waters have too much nitrogen in them, leading to nuisance algae blooms in the estuaries.
Constanze O’Toole, Ireland Development Manager at the Rivers Trust, says: “High levels of nitrogen and phosphorus can cause severe damage due to the eutrophication of water bodies. The high nutrient levels stimulate the growth of aquatic plants, especially alga. This over-growth can cause oxygen depletion and have a devastating effect on oxygen-sensitive macroinvertebrate species such as the mayfly, most stoneflies and cased caddisflies and can often cause fish kills in rivers.”
Parts of the east of the country have higher nitrate levels associated with urban wastewater discharges. Thirteen catchments are areas of particular concern due to elevated nitrogen concentrations. All these areas are located along the south, southeast and east coasts and include the rivers Maigue/Deel, Bandon, Lee, Blackwater, Suir, Nore, Barrow, Slaney, Tolka/Liffey (including the Dodder) and the Boyne.
Liz Gabbett, Project Officer at Maigue Rivers Trust, says: “This year the Maigue Rivers Trust began its citizen science water quality monitoring using Earthwatch's Freshwater kits, and the Trust's preliminary nitrates and phosphates analysis shows that nitrate levels continue to be too high in the Maigue catchment in 2021. It’s imperative that we continue to monitor levels closely, and then enact the solutions to reverse the decline.”