State of groundwater

Groundwater is an important natural resource. It acts as a reservoir from which good quality water can be abstracted for drinking, for use in industry and agriculture. It is also valuable for maintaining wetlands and river flows; acting as a buffer through dry periods.

Groundwater moves slowly through the ground and so the impact of human activities may last for a relatively long time. In fact, it may be difficult to clean up, even once the source of pollution has been removed. So, we need to focus on preventing pollution in the first place.

Groundwater provides base flow for surface water systems and so its quality may affect the quality of those surface waters. In other words, the effects of human activity on groundwater quality may impact on the quality of associated aquatic ecosystems and directly dependent terrestrial ecosystems.

The quality of the groundwater is threatened by various factors, such as leaching of nitrate and pesticides from cultivated land, as well as more restricted contamination from point sources, such as waste chemicals deposits, landfills, oil tanks and contaminated sites.

The following pages describe:

• Water quality and pollution by nutrients
• Water quality and pollution by hazardous substances