This layer contains marine and coastal features across Victoria. This data consists of conservation and protection zones, cultural and heritage areas, energy and resource extraction sites, defence and national security areas, locations of ports and shipping channels, fishing and aquaculture areas, and areas of natural environment and biodiversity importance.

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.

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.

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

Scientific review and dataset on developing a criteria for identifying key fish habitat locations and focussed on major Victorian bays and inlets (Port Philip Bay, Western Port, Corner Inlet and Gippsland Lakes). The recreational marine fish species habitat in the dataset are King george whiting, snapper, sand flathead, calamari, black bream and gummy shark. Commissioned by the Victorian Fisheries Authority (VFA) and later digitised by DELWP, the consultancy report was produced by the University of Melbourne. Kalu. Commissioned by VFA. developing criteria for identifying key fish habitat locations

Coastal Wave Model Statistics dataset is a high-resolution third-generation wave model based on unstructured grids. WAVEWATCH III was used to investigate the wave climate of Bass Strait and South-East Australia over the period 1981 to 2020. The model results are extensively validated against a network of coastal buoys and demonstrate that the model can capture the overall wave characteristics in this region. Analyses of model outputs across the 40-year period show that significant wave height has increased by approximately 5% and a slight counterclockwise rotation of peak wave direction has occurred with likely implications for coastal processes. Seasonal variations show higher significant wave height in winter compared to summer, which is driven by dominant Southern Ocean swell. The peak wave direction in the eastern region shifts from south-westerly in winter to south-easterly in summer. In autumn and winter, there is a statistically significant correlation between wave conditions and the Southern Annular Mode. During these seasons, a southward movement of Southern Ocean low pressure systems is associated with increased significant wave height, an increase in the peak wave period and a counterclockwise rotation of the peak wave direction. 1. Liu, J., Meucci, A., Liu, Q., Babanin, A. V., Ierodiaconou, D., & Young, I. R. (2022), The wave climate of Bass Strait and south-east Australia. Ocean Modelling, 172, 101980. https://doi.org/10.1016/j.ocemod.2022.101980. 2. Tran, H. Q., Provis, D., & Babanin, A. V. (2021), Hydrodynamic Climate of Port Phillip Bay. Journal of Marine Science and Engineering, 9(8), 898. https://doi.org/10.3390/jmse9080898

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.

20m resolution bathymetry and 5m contour intervals derived from 20m resolution bathymetry for nearshore Victorian Coast, LiDAR-derived bathymetry plus small area of multibeam-derived bathymetry on Westernport Bay. This dataset covers the Victorian coast, generally extending to the 20m depth contour. This dataset is based on information acquired between November 2008 and April 2009 to support the Victorian Governments Future Coasts Project.

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.