Groundwater is the water stored below ground in tiny cracks in the rock or in very small spaces between sand grains. It comes from rainwater that soaks into the ground into an aquifer. An aquifer is a body of rock and/or sediment that holds groundwater. The process of rain filling up an aquifer is called ‘recharge’. This is the Groundwater Recharge map. This shows where different amounts of rainfall reach the stores of groundwater (the ‘aquifers’) across Ireland. The estimated average annual recharge amount is shown in units of millimeters per year (mm/yr). The amount of recharge was figured over the period 1981-2010. This was then averaged to give a yearly amount.The map was created using the following datasets. Daily rainfall and daily potential evapotranspiration supplied by MetÉireann. Daily actual evapotranspiration for different soil drainage classes supplied by MÉRA/ICHEC. Groundwater vulnerability map supplied by GSI. Soil drainage map supplied by Teagasc. Generalised soil class map supplied by Teagasc/GWWG. Subsoil type map supplied by Teagasc/EPA & GSI. Subsoil permeability map supplied by GSI. Bedrock aquifer map supplied by GSI. Sand and gravel aquifer map supplied by GSI.The maps were overlain and interpreted to produce the groundwater recharge map for Ireland. This map is best displayed to the scale 1:40,000 (1cm on the map relates to a distance of 400m).It is a vector dataset. Vector data portray the world using points, lines, and polygons (areas). The recharge data is shown as polygons. Each polygon holds information on:ID (Internal Use Only).Average Recharge (mm/yr) - average annual recharge to the groundwater aquifer across that polygon.Hydrogeological Setting - the hydrogeological setting code, which is determined by the combinations of different geological layers.Hydrogeological Setting Description – the description of the hydrogeological setting that determines its setting code.Recharge Coefficient (%) – the proportion of effective rainfall that becomes groundwater.Effective Rainfall – the rainwater remaining after plants have taken up some of the rainfall.Recharge (pre cap) mm/yr – effective rainfall x recharge coefficient, not limited by maximum recharge capacities.Recharge Cap Apply – is there a maximum amount of recharge that the aquifer can accept? (Yes/ No).Maximum Recharge Capacity (mm/yr) – the maximum amount of recharge the aquifer can accept. Only applies to bedrock aquifers of category Ll, Pl, or Pu.Recharge Symbology (Internal Use only) – the recharge map legend classes.Groundwater Vulnerability – the code for the groundwater vulnerability(Which shows land areas where groundwater can be easily contaminated. It also shows areas where it is very well protected by the natural subsoil layers) – X, E, H, M or L.Groundwater Vulnerability Description – the groundwater vulnerability description.Soil Drainage – whether the soil is well drained or poorly drained (Wet or Dry).IFS_CODE (Internal Use only) – Teagasc Irish Forest Soils project soil category code.Subsoil Type – the code for the subsoil type.Subsoil Description – description of the subsoil type.Sand and Gravel Subsoil (Internal Use only) – whether the subsoil is sand/gravel or not.Peat (Internal Use only) – whether the soil is peat or not peat.Subsoil Permeability - the code for the subsoil permeability (relative ease with which water can flow through geological layers)of the subsoil – L, M, H or N/A.Subsoil Permeability Description – description of the subsoil permeability - Low, Moderate, High or N/A. Depth to Bedrock (Internal Use only) – Depth from Surface to the top of the bedrock.Karst - extreme vulnerability area designated by a 30 m buffer around a karst landform feature such as a swallow hole, enclosed depression or spring, etc.Sinking stream - extreme vulnerability area designated by a 15 m or 30 m buffer either side of a river stretch that gradually sinks into an aquifer. The stream might sink gradually into the aquifer below, or be part of a river reach that sinks into an aquifer further downstream.Gravel Aquifer Category - the code for the sand/gravel aquifer category - Rg or Lg.Gravel Aquifer Description - description of the sand/gravel aquifer category - Regionally important sand/gravel aquifer or Locally important sand/gravel aquifer.Bedrock Aquifer Category - the code for the bedrock aquifer category - Rk, Rkc, Rkd, Rf, Lm, Lk, Ll, Pl or Pu.Bedrock Aquifer Description - description of the bedrock aquifer category.Bedrock Unit Name (Internal Use only) - the formation or member name of the bedrock geology.Bedrock Description (Internal Use only) - the description of the bedrock unit.Rock Unit Group - the hydrostratigraphic rock unit group that the bedrock is part of.County - the county the polygon is in.