The experts who created the stormwater map have prepared a technical report. This report gives the:
- Technical methods, guidelines, and specifications used to prepare the map.
- Sequence of technical studies done to prepare the map, included as appendices.
- Other details to explain how the map was created.
The map shows areas where there is a possibility that a rare 100-year stormwater overland flow might impact the land. These areas are located within the local drainage region, where the Council has its drains.
Melbourne Water has added a stormwater map for the larger drainage areas in Merri-bek to the planning scheme.
More information about the stormwater map is in a Technical Report (PDF 5.5MB).
This is an updated map. We now have updated national guidelines and more information, allowing us to update our understanding of stormwater flows in Merri-bek.
Council wants the updated map to be informed by current data, methods and guidelines. You can find more information in a Technical Report (PDF 5.5MB), including in Appendix C.
It is the engineering and planning standard for managing stormwater risks for land development.
Before the 1970s, the '1 in 5 year' storm was the drainage design standard. The '1 in 100 year' standard initially came from the Drainage of Land Act in 1974.
In 2016, the Victorian Government's Floodplain Management Strategy confirmed the 1 in 100 year standard.
Requirements to prepare stormwater maps come from national engineering guidelines and specifications. Information about drains, the shape of land, and past severe storms are also used.
Specialist engineers, who have prepared stormwater maps for other councils, did the work. Separate reviewers check their work. Melbourne Water was also involved.
You can find more information in a Technical Report (PDF 5.5MB).
Portions of properties are included so future land development in the mapped area can consider the 1 in 100 year storm issues.
The reshaping of land can affect the passage of stormwater flows across the land. Therefore, the stormwater map sometimes includes portions of properties away from buildings.
Significant storms can affect all land. The land shown on the stormwater map is where 1 in 100 year overland flow affects the land.
Some properties are not included in the mapped area where there is a very low stormwater risk in a 1 in 100-year storm event.
At these locations, the edge of the map is straight to match the boundary of the removed property.
This helps to show that a specific property is not a part of the map.
You can find more information in a Technical Report (PDF 5.5MB).