Ireland’s rivers, lakes and estuaries carry evidence of all the human activities around them and, as the latest Environmental Protection Agency (EPA) report found, this burden is choking the life out of them.
The main stressor is agriculture, with cowpats, slurry and fertilisers, all rich in nitrogen and phosphorus, running off fields into adjoining waterways.
Dramatic changes result as these extra nutrients supercharge plant and algal growth, depleting the oxygen and blocking the light needed by other creatures.
But, looking at the issues facing a selection of catchments around the State, there are many other pressures that have left the waterways in trouble as a look at some of the most stressed catchments show.
RM Block
Mal Bay Catchment, Co Clare: Forestry
Clare might not be the county most associated with forestry in Ireland but forestry is listed as the number one challenge for at-risk water bodies in this west Clare catchment.
Commercially forested land empties herbicides and fertilisers into the waters and also adds acidity.
The combination is lethal to natural life in the waterways.
Urban wastewater is also a pressure, unsurprisingly given the well-publicised delays in upgrading outdated wastewater treatment plants in Lahinch and Ennistymon.
As with almost all catchments, agriculture is also a significant challenge.
Lough Swilly, Co Donegal: Urban wastewater
Despite its rural hinterland, the Lough Swilly catchment’s main issue outside of agriculture is urban wastewater.
The waters receive raw sewage from Ramelton and Rathmullan which are among the country’s remaining few villages without wastewater treatment facilities.
The impacts are felt further out into the lough, with Lady’s Bay in Buncrana being declared a no-swim zone for several years in a row because of the associated pollution.
Lower Shannon, Co Westmeath and Co Offaly: Hydromorphology
One of multiple catchments along Ireland’s longest river, agriculture is the chief concern but next to that is hydromorphology – the physical structure of the river and how human interference affects habitats and water flows.
Alterations to banks, the addition of weirs and culverts, dredging, water abstraction and gravel extraction changes the riverbed and vegetation needed to support wildlife, slow flood waters and filter impurities.
[ Raw and untreated sewage flowing into waterways amid delays to upgrade worksOpens in new window ]
Owenavorragh, Co Wexford: Domestic wastewater
The Owenavorragh catchment covers a largely rural area and agriculture is listed as the main pressure but after that comes domestic wastewater, an issue that arises primarily from older one-off homes with ageing septic tanks.
Homes built without connection to mains wastewater have to provide their own systems or septic tanks which need regular maintenance and cleaning to perform efficiently.
Nationally, there was a 56 per cent failure rate for inspected septic tanks last year. Wexford had a failure rate of 70 per cent.
Nanny-Delvin, Co Meath and Fingal: Multiple challenges
This catchment covers both rural and intensely built-up areas, taking in Donabate, Lusk, Skerries, Balbriggan, Stamullin, Laytown, Bettystown, Duleek, Ashbourne, Ratoath and Dunshaughlin.
Agriculture remains the key challenge but it has plenty of competition from urban and domestic wastewater, urban run-off from streets and roads, and hydromorphological changes.
Meath has one of the shortest coastlines in the country, at less than 20km (12.4 miles), and it is tainted by the pollution that makes it way out to the coast at Mornington Point.
Suir, Co Tipperary, Co Waterford, Co Kilkenny: Agriculture
This is one of the country’s largest catchments and it incorporates large urban centres including Waterford city, Clonmel, Carrick-on-Suir and Thurles.
But by far the greatest challenge for the Suir is agriculture with the three counties surrounding it well-known as highly productive beef and dairy lands.
The catchment suffered one of the biggest declines in health over the past five years, with 18 of its monitored water bodies deteriorating over that time.
