A spillage of raw sewage from the Ballycommon Wastewater Treatment Plant flowed into the Nenagh River last year. Its impacts on the river could be clearly seen upstream of the Ballyartella Weir (above).PHOTO: ODHRAN DUCIE

Nenagh River in 'bad condition' and Lough Derg polluted by nutrients

The Nenagh River is listed by the Environmental Protection Agency as one of four water bodies in the Republic to join the list that are classed in “bad condition”.

The downward classification for the river comes following a prolonged discharge of raw sewage from the Ballycommon Wastewater Treatment Plant into the waterway last year, as well as increasing pressure on urban waste water treatment plants due to economic development and population increases and a substantial increase in the dairy sector following the abolition of milk quotas almost a decade ago.

The Nenagh River, along with the River Laune in Kerry and the Annagh in Clare, are named by the agency as the latest to be added to rivers across the country that declined to bad status in recent years.

The EPA in its latest report said the Nenagh River was one of those now “impacted by multiple pressures such as agriculture, urban wastewater and other human activities”.

The agency also lists other water bodies in Tipperary where water quality is declining.

Among those listed in the report are the rivers Shannon, Suir and the Nore.

The water quality report found that of all the rivers in the State, water quality was high or good in 55 per cent of cases.

However, the Nenagh River, Shannon, Suir, Nore which all flow through Tipperary are in the remaining 45 percent that are in moderate, poor or, as in the case of Nenagh, “bad” condition.


Lough Derg is also being negatively impacted by growing pollution.

The EPA said the majority of lakes failing to achieve good biological quality are in the Shannon and Erne catchments. These were “areas with elevated lake phosphorous levels”.

More than half (54%) of over 200 lakes monitored by the agency are in high or good biological quality.

Eleven lakes were in bad biological quality - the worst class.


The report found that nitrates, which the agency said comes mainly from the agriculture sector, was impacting negatively on rivers and lakes.

Nitrate concentrations monitored in the years 2021 to 2023 show that 42% of river sites nationally have unsatisfactory levels.

Concentrations of this runoff into rivers and lakes saw little change over the past several years.

And the EPA pointed out this was also the case for phosphates, which it said emanated from waste water, industrial discharges and run off of organic and inorganic fertilisers from agricultural land.

The report states that over one quarter (27%) of sites have unsatisfactory phosphate concentrations.

The remaining sites are at levels which support high (58%) or good (15%) water quality.

The Midlands, South East, East and South West exhibit the highest average river phosphate concentrations in the country.

The agency said increased concentrations of phosphorous in lakes can lead to “a significant decrease in water quality due to an overgrowth of plants and algal blooms”.

Algal blooms occur almost annually on Lough Derg for at least the past three decades.

It said phosphates can negatively affect the ecology of lakes and those with elevated levels “can often have a characteristic ‘pea soup’ appearance due to the intense algal blooms”.

In the period 2021-2023, over one third (35%) of lakes had unsatisfactory total phosphorous concentrations.

The report identified unsatisfactory levels of phosphorous in Lough Derg.


The report concluded that “there has been no significant change in nutrient concentrations or in the biological quality of our rivers and lakes in 2023”.

“As in recent years, any improvements in biological quality are being offset, and at times exceeded, by declines elsewhere.

“Nationally, average concentrations of nutrients appear to have stabilised. However, levels of nitrogen are still too high in 42% of river sites and 20% of groundwaters.

“Levels of phosphorous are still too high in 27% of river sites and 35% of lakes.

“These losses of nutrients damage the ecology of our rivers and lakes, and make their way into the marine environment, putting continued pressure on our estuarine and coastal waters.”

The EPA concluded: “We will not see an overall improvement in water quality, or meet our water quality objectives, until nutrient levels reduce. There is no indication yet that this is happening.”


Tipperary Independent TD Michael Lowry said agriculture must not become the “fall guy” for nature restoration.

“This is the risk and hazard to Irish farmers,” said Mr Lowry when addressing the Regional Group of TDs' motion on Nature Restoration in the Dáil on Wednesday of last week.

He called on the Government “to give a firm guarantee that agricultural activities, prudently managed, can and will continue on farmland in Tipperary and across the country.

“It is imperative that the agricultural sector will not become the financial fall-guy in our efforts to achieve our targets,” said Mr Lowry.