Karst is a type of landscape where the bedrock has dissolved and created features such as caves, enclosed depressions (sinkholes), disappearing streams, springs and turloughs (seasonal lakes). Limestone is the most common type of soluble rock. As rain falls it picks up carbon dioxide (CO2) in the air. When this rain reaches the ground and passes through the soil it picks up more CO2 and forms a weak acid solution. The acidified rain water trickles down through cracks and holes in the limestone and over time dissolves the rock. After traveling underground, sometimes for long distances, this water is then discharged at springs, many of which are cave entrances.

There are many kinds of karst landforms, ranging in size from millimetres to kilometres. Dolines or sinkholes are small to medium sized enclosed depressions. Uvalas and poljes are large enclosed depressions. A swallow hole is the point where surface stream sinks underground. Turloughs are seasonal lakes. Springs occur where groundwater comes out at the surface, karst springs are usually much bigger than non-karst springs. Estevelles can act as springs or swallow holes. Dry valleys are similar to normal river valleys except they do not have a stream flowing at the bottom. A cave is a natural underground opening in rock large enough for a person to enter. Superficial Solution Features can be seen on rocks dissolved by rain and include pits, grooves, channels, clints (blocks) and grikes (joints). Please read the lineage for further details.

This map shows the currently mapped karst landforms in Ireland.

Geologists map and record information in the field. They also examine old maps and aerial photos.

We collect new data to update our map and also use data made available from other sources such as academia and consultants.

It is NOT a complete database and only shows areas that have been mapped by GSI, or submitted to the GSI. Many karst features are not included in this database. The user should not rely only on this database, and should undertake their own site study for karst features in the area of interest if needed.

It is a vector dataset. Vector data portray the world using points, lines, and polygons (areas).

The karst data is shown as points. Each point holds information on: Karst Feature Unique ID, Historic GSI Karst Feature ID, Karst Feature Type, Karst Feature Name, if it’s within another Karst Feature, Location Accuracy, Data Source, Comments, Details and County.

Water tracing means ‘tagging’ water, usually by adding a colour or dye, to see where it goes. Dye is usually added to a sinking stream and all possible outlet points (such as springs and rivers) are tested for the dye.

Water traces are recorded as a straight line between the location of tracer input (e.g. swallow hole) and detection (e.g. spring), but they don’t show the actual path water may take underground, which is likely to be much more winding.

It is mainly used in karst areas to find out groundwater flow rates, the direction the water is travelling underground and to help define catchments (Zone of Contributions).

The dataset should be used alongside the Karst Landforms 1:40,000 Ireland (ROI/NI) ITM.

Geologists map and record information in the field. We collect new data to update our map and also use data made available from other sources such as Academia and Consultants.

It is a vector dataset. Vector data portray the world using points, lines, and polygons (areas).

The karst data is shown as lines. Each line holds information on: Tracer Line Unique ID, Input Site, Input Historic GSI Karst Feature ID, Output Site. Output Historic GSI Karst Feature ID, Tracer Test Date, Weather Conditions, Tracer Used, Quantity, Operator, Results, Minimum Groundwater Flow Rate, Hydraulic Gradient (slope of water table), Data Source, Catchment, Peak Concentration, Other Information, Flow Path, County, Length (m), Direction and Quality Checked.