GSI Groundwater Resources Bedrock Aquifers

Different aquifers have differing Abilities to store and transmit water. Based on the hydrogeological characteristics and on the value of the Groundwater resource, GSI has classified Ireland’s land surface into aquifer categories. GSI aquifer classes are divided into three main groups based on their resource potential (Regionally or Locally important, or Poor), and further subdivided based on the type of openings through which Groundwater flows (through fissures, Karst conduits or intergranular). There are nine aquifer categories in total. This is a polygon Dataset containing nine Bedrock aquifer classes. Scale: 1:100,000 1) Regionally Important Aquifers: Regionally important aquifers are capable of Supplying regionally important abstractions (e.g. large public water supplies), or excellent yields (> 400 m³/d). Bedrock aquifer units Generally have a continuous area of > 25 km² and Groundwater predominantly flows through fractures, fissures, joints or conduits. Regionally important sand/gravel aquifers are > 10 km², and Groundwater flows between the sand and gravel grains. This group is subdivided into the following types: RK Regionally Important Karstified Bedrock aquifer RF Regionally Important Fissured Bedrock aquifer RG Regionally Important Sand/Gravel aquifer Regionally important karstified aquifers may be further subdivided based on the whether Groundwater flows mainly through conduits (RKC) or more diffusely through solutionally-enlarged fissures (rkd). 2) Locally Important Aquifers: Locally important aquifers are capable of Supplying Locally important abstractions (e.g. smaller public water supplies, group schemes), or good yields (100-400 m³/d). In the Bedrock aquifers, Groundwater predominantly flows through fractures, fissures, joints or conduits. Locally important sand/gravel aquifers are typically > 1 km², and Groundwater flows between the sand and gravel grains. This group is subdivided into the following types: LM Locally Important Bedrock aquifer, Generally Moderately productive Ll Locally Important Bedrock aquifer, Moderately productive only in Local Zones LK Locally Important Karstified Bedrock aquifer LG Locally Important Sand/Gravel aquifer 3) Poor Aquifers: These Bedrock aquifers are capable of Supplying small abstractions (e.g. domestic supplies, small group schemes), or moderate to low yields (< 100 m³/d). Groundwater abundantly flows through a limited and poorly-connected network of fractures, fissures and joints. This group is subdivided into the following types: PL Poor Bedrock aquifer, Generally unproductive except in Local Zones PU Poor Bedrock aquifer, Generally unproductive The aquifer maps along with the Groundwater Vulnerability map and Source Protection Area maps are merged to produce Groundwater Protection Zones. Each zone enables an assessment of the risk to Groundwater, independent of any particular hazard or contaminant type. The Groundwater Protection Zones form one of two components of Groundwater Protection Schemes. A Groundwater Protection Scheme provides guidelines for the planning and licensing authorities in Carrying out their functions, and a framework to assist in decision-making on the location, nature and control of developments and activities in order to protect Groundwater. Use of a scheme will help to ensure that within the planning and licensing processes due regard is taken of the need to maintain the beneficial use of Groundwater. Groundwater Protection Schemes are county-based projects that are undertaken jointly between the GSI and the respective Local Authority. The Groundwater protection scheme comprises two components: • A land surface zoning map (or maps) called the Groundwater protection zone map, and • Groundwater protection responses for existing and new potentially polluting activities. The role of the GSI is in the production of the land surface zoning map, Whereas decisions on Groundwater protection responses are the responsibility of the statutory authorities.