Some of Ireland’s rivers could lose in excess of 30% of their existing water levels during dry weather from the middle of the century, environmental researchers have warned.
Research commissioned by Irish Water found that many rivers in the west and south of the country are most prone to the effects of climate change.
The study by the Irish Climate Analysis Research UnitS (ICARUS) at Maynooth University carried out a detailed examination of 206 river catchments identified as sensitive to the impact of current and future climate change.
It assessed their sensitivity to changes in both annual rainfall and changes in the seasonality of rainfall through wetter winters and drier summers.
Predictions were modelled on there being an average temperature increase of 2ºC relative to the period 1976-2005.
The report found that most river catchments predominantly located along the wetter, western seaboard and uplands have a poor natural storage capacity and are most sensitive to changes in the seasonality of rainfall due to climate change.
It claimed they could experience a pronounced decrease in water levels as a result of wetter winters and drier summers even though overall rainfall levels could increase by around 20%.
River catchments in the midlands and east are drier, low lying and have greater natural storage to withstand reduced summer rainfall than other parts of the country.
While it was still forecast they would experience reductions in flow, they are likely to be less affected by changes in the seasonality of rainfall.
The study excluded heavily modified catchments including the River Liffey and River Shannon.
It found that changes in the annual amount and seasonality of rainfall were most likely to have an impact on rivers with a “shorter memory” which were predominantly upland systems with an impermeable geology and thin peaty soils.
The report said the findings will assist Irish Water in assessing the sustainability of abstracting water from different catchments both now and in the future for public water supplies.
However, it also recommended the need for further research in the area with the involvement of other State agencies including the ESB and OPW.
The study’s findings will be used to inform Irish Water’s National Water Resources Plan which in turn will inform decision-making about the company’s investment in projects to ensure safe and reliable water supplies to customers.
For the first time in Ireland, the research took a “bottom up” approach by conducting a detailed examination of the characteristics of each river catchment area to determine its vulnerabilities.
The research was funded by the Water Services Innovation Fund established by the Commission for the Regulation of Utilities to encourage Irish Water to implement and invest in research projects that have the potential to improve how water services are delivered.
A total of €4m is available in each of the periods 2015-2019 and 2020-2024.
“Successful projects may allow Irish Water to become more efficient and effective in its day-to-day operations,” the CRU said.
It added: “However, research projects that do not achieve their desired outcomes are still of benefit as they allow Irish Water to better understand its assets, activities and customers.”