EPA - Ireland's Environment, An Integrated Assessment - 2020

Chapter 7: Water Quality The State of Our Groundwaters With a few localised exceptions, the quality of groundwater in Ireland is generally good. At least 92 per cent of groundwater bodies have good chemical and quantitative status, and the amount of rainfall replenishing groundwater is generally enough to sustainably support the volume of water being abstracted. Groundwater is water located in spaces and cracks in rocks and the subsoil. It is the source of drinking water for approximately one-quarter of the population in Ireland and contributes a significant proportion of the flow in our rivers during dry weather. The quality of groundwater in Ireland is good: 92 per cent of groundwater water bodies have good chemical status (Figure 7.8; EPA, 2019a). Water bodies that failed to meet their objectives (38 water bodies in total) are typically associated with historical contamination from industrial sites and, although significant, this pollution is generally very localised. Since 2013, nitrogen concentrations in groundwater, predominantly arising from losses to groundwater from agricultural soils, have started to increase in the southern and south-eastern parts of the country. The microbiological quality of groundwater is also an important factor in areas where wells and boreholes are used to abstract drinking water. The risks from the presence of microbial pathogens such as verocytotoxin- producing Escherichia coli (VTEC) needs to be considered when sourcing and using drinking water for household wells. Drinking water and VTEC is covered in Chapter 14. Over 99 per cent of groundwater bodies have good quantitative status, i.e. the amount of rainfall replenishing groundwater is generally enough to sustainably support the volume of water being abstracted (Figure 7.7). Only two groundwater bodies failed to achieve good quantitative status. Similarly, the volume, location and operation of groundwater abstractions mean that very few groundwater abstractions deplete surface water resources. The National River Basin Management Plan highlighted that only 6 per cent of water bodies require further assessment of water abstraction pressures. Nonetheless, there is a small number of groundwater abstractions that, while not currently causing an environmental impact, may require active management to ensure that they remain environmentally sustainable in the context of a changing climate and the impact that may have on water resources. The Environmental Protection Agency (EPA) is reviewing the data gathered under the 2018 Abstraction Registration Regulations (S.I. No. 261/2018) to identify those abstractions that put significant pressure on water bodies, potentially preventing them from achieving their environmental objectives, and require measures to ensure that they are managed sustainably. Figure 7.8  Chemical and quantitative status of groundwater, 2013-2018 (Source: EPA) Good Failing to achieve good Good Poor Quantitative Status Chemical Status 1% 99% 92% 8% 169