IE GSI Subsoil Permeability 40k Ireland (ROI) ITM WMS

Groundwater is the water that soaks into the ground from rain and can be stored beneath the ground. Groundwater is used to supply drinking water and needs to be protected. It is mainly protected by layers of subsoils, sands or peats. Knowing how easy it is for rainwater (which may contain pollutants) to soak down through the subsoils is important. The ease with which water can pass through the subsoils is known as the ‘permeability’.

Subsoil permeability along with the subsoil depth, tells us how well protected the groundwater is and how vulnerable the groundwater is to pollution. Knowing this helps people to plan and carry out activities on the land in a way that keeps our groundwater safe to drink.

The permeability of subsoil also affects how easily rainwater can soak down into the ground and fill up the groundwater resource (aquifer). An aquifer is a body of rock and/or sediment that holds groundwater. Subsoil permeability is used to create the groundwater recharge map which shows where different amounts of rainfall reach the stores of groundwater (aquifers) across the country. Knowing the location and amount of groundwater recharge is important. It helps us to identify groundwater sources which can be used to supply drinking water. It also helps us to manage the water supply sustainably. The recharge map can help us to understand where there might be too much groundwater being taken from the ground compared to what seeps down to replenish it.