The impact of on-site wastewater treatment for small community developments on groundwater quality

Groundwater is an increasingly important resource in Ireland. Over the coming years it is estimated that water supply arising from groundwater sources will rise, with increasing pressures on current supplies and the possible introduction of water charges. Groundwater also accounts for a significant proportion of base flow for many of our streams and rivers around the country. It is therefore of great importance that we maintain the quality of our groundwater resources into the future.

Over the past number of years there has been a large increase in the number of small community developments outside of urban areas, often referred to as cluster developments. Planning policy varies across the country towards these types of developments and it is not generally known what (if any) impact these kinds of development and their density has on groundwater quality.

This current research is evaluating groundwater quality at separate cluster developments in different areas of groundwater vulnerability. Continued monitoring of these study sites will take account of seasonal variances such as agricultural practices and fluctuations in the groundwater table. It is hoped that the results of this study will indicate if the density of cluster developments using de-centralised wastewater treatment systems has an impact on groundwater quality. This study will be used to develop a model which in turn could assist local authorities when planning future developments.