This layer provides boundaries for the management of groundwater in Victoria and is a product of the NWC funded Secure Allocations, Future Entitlement (SAFE) Project. The Groundwater Management Basins (GMB) layer has been derived from the Groundwater Catchments (GCs). Both the GMBs and GCs have been developed to provide complete coverage of Victoria while considering the following: (1) Reflect aquifer systems and groundwater movement; and, (2) Align with physical (i.e. surface water) and administrative boundaries where appropriate. The GCs are aligned with the GMBs. Boundaries that related directly or in-directly to the physical characteristics of groundwater resources included groundwater flow divides, surface water flow divides, topographic divides, and geological structural features that influence aquifer extent and groundwater flow direction. There are five Groundwater Management Basins (GMBs) in Victoria. Each basin encompasses a number of Groundwater Catchments (GCs): (1) Goulburn Murray Basin: includes the Loddon, Campaspe, Goulburn-Broken, Ovens and Upper Murray Groundwater Catchments; (2) Wimmera-Mallee Basin: includes the Wimmera-Mallee, West Wimmera and Avoca Groundwater Catchments; (3) Otway-Torquay Basin: includes the Glenelg, Portland and Hopkins-Corangamite and Otway Torquay Groundwater Catchments; (4) For ease of reporting: Port Phillip, Westernport and Tarwin Basins are grouped into Central Basin. Central Basin includes: West Port Phillip Bay, East Port Phillip Bay, Westernport and Tarwin Groundwater Catchments; (5) Gippsland Basin: includes East Gippsland, Central Gippsland and Seaspray Groundwater Catchments.

This dataset representst Victoria’s Groundwater Management Areas (GMAs) Where groundwater has been intensively developed in Victoria, or has the potential to be developed, Groundwater Management Areas (GMAs) are established and the Permissible Consumptive Volume (PCV) is progressively set. Monitoring of the groundwater resource in these areas is undertaken by the Department of Sustainability and Environment through the State Groundwater Monitoring Network. Water levels and the amount of water allocated to groundwater users in the areas are closely monitored.

## **Abstract** This dataset and its metadata statement were supplied to the Bioregional Assessment Programme by a third party and are presented here as originally supplied. DEPI originally engaged GHD to develop seamless 3D aquifer surfaces for the Victorian Aquifer Framework (VAF). The seamless mapping of aquifers across the state provides the fundamental framework for groundwater resource management, underpins development of a revised management structure for Victoria (the Secure Allocation Future Entitlement project funded by the National Water Commission) and contributes to the data needs of the Bureau of Meteorology National Groundwater Information System (NGIS). The original dataset was produced by GHD in 2012 using (in part) data provided by Southern Rural Water Corporation and Goulburn-Murray Water Corporation. It has been subsequently amended by Hocking et al and SKM in 2013. ## **Dataset History** A number of key input datasets were sourced as part of the process to derive the 3D aquifer surfaces. These datasets included: The DEPI State-wide Stratigraphic Database (SSD); The National Groundwater Information System (NGIS) database containing groundwater borehole location information as well as lithological and stratigraphic information; Raster layers previously produced for Southern Rural Water (SRW) by SKM and GHD in 2009; The crystalline basement surface provided by the former Department of Primary Industries (DPI); Outcrop 1:250,000 scale geological mapping compiled by the former Geological Survey of Victoria, DPI; A state-wide 100m Digital Elevation Model (DEM) based on the DEPI 20m DEM. This was used to represent the natural surface; Data generated using DEPI's state-wide ecoMarkets groundwater modelling package to assist with the definition of key layers of the major Cainozoic aquifers; Latrobe Valley Coal Model which was used to provide a framework for the hydro-stratigraphy of the wet Gippsland Basin; Rasters of the top elevation of the major aquifer systems covering the Kiewa, Ovens, Goulburn-Broken and Loddon and Campaspe catchments; Data extracted from the Basin in a Box, the Murray Basin Hydrological Map Series and the Murray-Darling Basin Groundwater Status 1990-2000: Summary Report; Airborne magnetic data publicly available from raster data published by the former Geological Survey of Victoria, DPI. Once the input data had been compiled, the VAF 3D surfaces were developed by lfollowing a number of key steps, summarised below: (1) Contours as polylines and aquifer extents as polygons were extracted from previous mapping surfaces; (2) Outcrop points attributed with values from the DEM were created; (3) Based on the state-wide stratigraphic database, the contours and extents were refined or created; (4) A top elevation raster was interpolated using contours, outcrop points and bore data then replacing outcrop areas with the DEM; (5) The aquifer thickness was then checked in GIS by comparing layers against each other and assessing for cross-overs and negative thickness; (6) The input data was then revised and bore data, contours, and aquifer extents modified as required due to errors in the thickness; (7) If there were subsequent issues identified such as overlaps between aquifers, mismatches between bores and resulting layers, then the process was revised by returning to Step (3); (8) If the layers were matching well, then extent points were created to smooth layers at the edges; (9) A top elevation raster was generated again using contours, outcrop points, extent points and bore data; (10) The aquifer thickness was checked again, and if significant issues were identified, then the process returned back to Step (3) for further iteration; (11) Further modifications were applied to remove negative thicknesses and to provide minimum thickness of overburden; (12) Top and bottom elevation rasters were then generated at 100m pixel resolution to form the final dataset. In generating each of the layers, a number

The Australian Hydrological Geospatial Fabric Surface Hydrology Catchments dataset was used as the base layer for considering surface water as an asset. This dataset provided mapped major rivers for Victoria. Numerous investigations into the interaction between groundwater and surface water have occurred across Victoria. Where this information was available in a format suitable for use in a GIS, it was collated to inform a state wide dataset of groundwater and surface water interaction. The resulting product attributes the stream base layer (described above) with the following classification of groundwater and surface water interaction: Gaining Variable Neutral/Losing Unclassified

This layer provides the boundaries of the River Basins of Victoria, and is part of a system devised by the Australian Water Resources Council (AWRC). The basins within Victoria are contained within two drainage divisions; the Murray Darling Division and the South East Coast Division.

Australia's River Basins 1997 is the result of a joint State, Territory and Commonwealth Government project to create a national spatial database of major hydrological basins. It shows the boundaries of Australia's basins as defined by the Australian Water Resources Management Committee (WRMC). Australia is divided into drainage divisions which are sub-divided into water regions which are in-turn sub-divided into river basins. The data includes the name and number of each of the 245 drainage basins, 77 regions, and 12 divisions. This metadata was prepared for the eAtlas and is not authoritative. Please contact the custodian for an authoritative record. Data Location: A copy of this dataset is filed in the eAtlas enduring data repository at: data\other\AU_GA_River-basins-1997