54. Hanns Inlet - Relict Spits and Tidal Inlets

This information has been developed from one or more of these publications:

Sites of Geological and Geomorphological Significance in the Westernport Bay Catchment (1984) by Neville Rosengren.
Sites of Geological and Geomorphological Significance in the Western Region of Melbourne (1986) by Neville Rosengren
Sites of Geological and Geomorphological Significance on the Coast of Port Phillip Bay (1988) by Neville Rosengren.
Sites of Environmental Significance in the Flood Plain of the Upper Yarra Valley Region (1983) by Neville Rosengren, Douglas Frood and Kim Lowe (as part of a study of Sites of Environmental Significance by the University of Melbourne for the then Upper Yarra Valley and Dandenong Ranges Authority).

Geological heritage sites, including sites of geomorphological interest and volcanic heritage sites, are under regular revision by the Geological Society of Australia, especially in the assessment of significance and values. Reference should be made to the most recent reports. See the Earth Science Heritage section of the Geological Society of Australia website (external link) for details of geological heritage reports, and a bibliography.

Location:	Somers – 441490. Southern entrance to Hanns Inlet. The area lies inside the Flinders Naval Depot.	Site 54, Sandy Point area
Access:	The area is closed to the public and permission for access must be obtained from the appropriate officer at the Naval Depot.
Ownership:	Commonwealth Government land (RAN Flinders Naval Depot.)
Geology/Geomorphology:	The area illustrates features of a rapidly prograding shoreline where the nature of sedimentation has changed. Presently the shore is mangrove fringed and landward of this is a saltmarsh zone over 300 metres wide. The predominant sediment regime is silt and mud with minor component of sand. Landward of the saltmarsh zone are low but distinct ridges which are sandy and originated as small recurving spits breached by tidal inflow. The former tidal channels now terminate as shallow depressions and rarely transmit tidal flow.
Significance:	State. The relict spits indicate a rapid change in the sediment regime of Hanns Inlet due probably to the extension of Sandy Point. This reduced the sand supply into the inlet and allowed rapid reduction progradation of mudflats colonized by mangrove and salt marsh.
Management:	Class 1. No disturbance to the mangrove, salt marsh, and relict spit system, for example by dumping of dredge spoil or coastal engineering works should be permitted.

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