Areas of catchments that drain directly to Victorian estuaries - i.e. not via major freshwater tributaries. This data updates the previous EST_CATCH (Deakin) layer for use in the 2021 Index of Estuarine Condition. Boundaries were determined from a digital elevation model (DEM) and were compared with DELWP boundaries for some estuaries (where DELWP data existed (i.e. in the estuary fluvial catchment layer [WATER_EST_FLUV_VSDL] available on the Victorian Spatial Data Library [January 2020]). On steep land (the Otways, east Gippsland etc) the boundaries align well. On the flatter areas there are some discrepancies between the DEM derived boundary and the DELWP derived boundary. For some catchments the DELWP boundaries are more accurate, but for others the DEM derived boundary is more accurate. Final catchment boundaries were determined by adopting the DEM derived boundary where there was good alignment with the DELWP layer and then adjusting just the contested boundaries to choose the one that appeared most accurate based on the rationale specified for each estuary below.

This layer contains species distribution maps for taxa groups across the Victorian coastline.

IEC2021_SUB_VEG is the spatial representation of submerged vegetation used in the calculation of Index of Estuarine Condition (IEC) scores. In the context of the IEC, 'submerged vegetation' refers to aquatic plants attached to bottom sediments that are generally entirely submerged but may be exposed during very low tides. Field data was collected at various locations within the estuary to ground-truth the mapping of full coverage derived from available aerial imagery. The field data was collected in late spring, summer and early autumn to correspond with warmer water temperatures and longer photoperiods, and to avoid winter periods of submerged vegetation dieback. In the field, ground-truthing by taking photos of the benthic environment largely followed the protocols outlined in Woodland and Cook (2015). If the estuarine bed was visible, photographic samples were collected of the different vegetation types present. Coverages of these different vegetation types (e.g. dense, sparse) were also photographed as well as bare ground. Ground-truthed benthic images were mapped over high-resolution (<20 cm) aerial imagery sourced from the DELWP imagery archive. Only imagery later than 2010 was considered, with most of the imagery used captured later than 2015. RPAS imagery collected for some estuaries was geo-rectified and mosaicked to provide very high-resolution imagery for mapping. Mapped areas were then compared to the geo-referenced ground-truthed benthic images and assigned a vegetation-coverage class and an indication of classification confidence (High, Medium or Low). For each estuary, MA:TV was then derived from the ratio of total macroalgae area to total vegetated area (i.e. seagrass and macroalgae) as per Woodland and Cook (2015). Briefly, vegetated habitat areas were weighted by their coverage classes such that polygons assigned `sparse¿medium¿ coverage were considered to contain 50% vegetation, and those assigned as `dense¿ coverage were considered as 100% vegetated. The ratio of macroalgae to total vegetation (MA:TV) was calculated as the sum of the weighted macroalgae areas divided by the sum of the weighted seagrass and macroalgae areas. MA:TV ranges from 0 to 1.

This layer contains divisions of Victorian biounits as classified to CBICs Level 4 biotope complexes as points. At this level of the hierarchy, biotopes are grouped into sets with similar physical and biological characteristics.

IEC2021_ESTUARY_BOUNDARIES is the spatial boundaries of the merged polygons in the IEC2021_SUB_VEG layer.

This layer contains divisions of Victorian biounits as classified to CBICs Level 4 biotope complexes as lines. At this level of the hierarchy, biotopes are grouped into sets with similar physical and biological characteristics.

Victorian State-wide dataset containing features of interest including boating clubs, camping grounds, caravan parks, historic sites, lifesaving clubs and lookouts as identified by the Victorian Regional Coastal Boards and reviewed as part of the Future Coasts SECAP project.

Key Biodiversity Areas dataset shows Victorian places of global significance for the conservation of birds and other wildlife which must meet strict, international scientific criteria. This dataset has been updated as of March 2022 to ensure all boundaries are clean of overlaps and slivers and all Key Biodiversity Areas are displayed as single features rather than multi-part polygons. There are 334 KBAs in this dataset. Visit https://www.birdlife.org.au/projects/KBA for more info.

This layer contains regional biogeographical divisions of Victorian State waters as classified to CBICs Level 6 biogeographical units (biounits). Each biounit is characterised by one or more distinct physiographic settings, ecosystem processes and biotope distributions. These regions form a basis for ecological studies, natural resource management and ecological modelling.

The IEC is made up of five subindices - Physical Form, Hydrology, Water Quality, Flora, and Fish. The overall score for each estuary is based on individual scores for the five sub-indices. Sub-indices are made up of one or more measures that, in turn, are underpinned by one or more metrics that provide information on threats or condition (DELWP 2021). Assigning each IEC metric to represent measures of either threat or condition aids interpretation of results and conceptual understanding of observed estuary condition to guide management options.