Spatial information for Integrated Coastal Zone Management (ICZM): an example from the artificial Entrance Channel of the Gippsland Lakes, Australia

Since 1889, an artificial entrance channel, cut through the swash aligned Holocene sandy outer barrier system known as the Ninety Mile Beach, has provided shipping access between the Gippsland Lakes and Bass Strait. From digital spatial data analysis using GIS-built versions of the hydrographic chart archive (spanning the years 1889-2005) accumulated by port authorities, both visual and net volumetric analyses of time-series Entrance Channel morphological changes have been made. Since the mid-1970s, channel sedimentation has imposed rising demands upon maintenance dredging regimes, which is a tendency that parallels the decline in streamflow discharge from the Gippsland Lakes catchment, and correlates with the introduction of specific sediment management regimes. Clear public policy implications emerge. They refer to the continued need for provision of a navigable shipping channel that will also be of sufficient depth to allow the escape to Bass Strait of any future catchment floodwaters. It is argued that adoption of a spatial data intensive Coastal Action Plan approach be considered in the future, to allow already established Victorian State Integrated Coastal Zone Management (ICZM) policy to be brought into practice.