The CFEV Groundwater Dependent Ecosystems (GDEs) data layer shows generalised point locations of known freshwater-dependent ecosystems highly dependent on groundwater across Tasmania. This layer mainly includes various types of springs. Conservation rankings for karst are not included in this layer and are provided separately in the CFEV Karst data set.

The CFEV GDEs point data layer was modified from a selection of known locations of freshwater-dependent ecosystems highly dependent on groundwater which were nominated by a variety of experts in the fields of earth science, botany and zoology. In many instances, certain identified types of GDEs were addressed through the CFEV assessment of other ecosystem types (e.g. vegetation types, such as alkaline pans and sedge rush wetlands being considered in the wetlands assessment). A GDE data layer was created using points to represent the locations of GDE types not being picked up by other assessments. The point localities cover the following classes of GDEs: - Cold springs (karstic) â¿¿ springs (often at cave entrances) where water temperature is unaffected by geothermal heating. - Mound springs â¿¿ a tufa-depositing spring where the calcareous material is deposited by groundwater under pressure to produce a raised mound or hillock. - Sub-surface streams in talus and colluvium. - Tufa-depositing springs â¿¿ spring where calcareous material (tufa) has been deposited by groundwater. - Warm springs â¿¿ springs where the water temperature has been raised through geothermal heating. Many of the springs mapped as point localities are cave entrances. In the interests of cave conservation and public safety, this information was considered sensitive and as such, the easting and northing data associated with this data was generalised so the exact location is not disclosed. The GDE point data were not assessed for conservation value and conservation management priority, as per other freshwater-dependent ecosystems, due to a lack of specific input data to go into the CFEV assessment process. Additonal information on the selection of GDEs and the CFEV Program is provided on the website (http://dpipwe.tas.gov.au/water/water-monitoring-and-assessment/cfev-program) and in the CFEV Project Technical Report (http://dpipwe.tas.gov.au/water/water-monitoring-and-assessment/cfev-program/cfev-resources#TheCFEVTechnicalReport). Limitations: Not a comprehensive inventory of all GDEs. Only lists those known by experts and only includes those GDEs not considered to be assessed within other ecosystem themes. For a full list of known GDEs identified by the experts, see Eberhard (2004). Currency: The mapping of GDEs for the CFEV Program was completed and released in 2005.