The CFEV Sub-catchments data layer shows the sub-catchment boundaries within the major drainage catchments in Tasmania. It is part of a set of nested catchments for the state which reduce in size from the major catchments to sub-catchments to fine-scale river section catchments.

The CFEV Sub-catchments data layer was generated by amalgamating CFEV River Section Catchments. This data provides an intermediate scale of catchment boundaries (between CFEV River Section Catchments and the CFEV major drainage catchments) which was thought to be a more useful scale for management purposes. A technique for catchment aggregation was developed to allow different scale catchment regions to be created. Catchments are accumulated downstream until a suitable region is formed, at which stage the process starts again. Methods for terminating catchment regions can be based on: - minimum or maximum size requirements - stream order changes - explicit terminal locations River Section Catchments were aggregated to create sub-catchments to a maximum size of 40,000 ha with the exception of larger sub-catchments created to be able to include large waterbodies (i.e. Great Lake, Lake Gordon and Lake Pedder). Additional details on the CFEV sub-catchments can be found in the CFEV Project Technical Report (http://dpipwe.tas.gov.au/water/water-monitoring-and-assessment/cfev-program/cfev-resources#TheCFEVTechnicalReport). Currency: The mapping of the sub-catchments for the CFEV Program was completed and released in 2005. Completeness: The CFEV Sub-catchments data set is complete for all Tasmania excluding Macquarie Island.