If a proposed development is in a Special Building Overlay, a planning permit is required for subdivision or buildings and works.
The planning permit application assessment process will include having the planning application referred to a floodplain management authority (your CMA or Melbourne Water) for review.
In the normal planning permit process, council will send your plans to the relevant FMA/CMA. For VicSmart applicants, you need to forward your plans to the relevant FMA/CMA for approval before you lodge your VicSmart planning application with the council.
To locate the relevant FMA/CMA and get contact details, use this Interactive Map of Floodplain Management Authorities (FMAs/CMAs).
Source: Floodplain Planning by the State of Victoria