The coastal environment is the interface between the forces of the sea and those on land. It is a naturally dynamic environment and is constantly evolving. Coastal environments and landscapes are also defined by their unique biological diversity. Human use and activity adds to the complexity and dynamism of the coastal environment.
Probably the most significant dynamic element that needs to be managed in the coastal environment in the future is climate change. The best science now tells us that we can expect climate change "with certainty", and that sea level change and changing weather conditions will have the most significant impact on coastal planning and management. Enhanced coastal erosion by storm events and changed weather patterns is a likely outcome that we will need to plan for and manage over the coming years.
Direct impacts are likely to be increased and altered patterns of erosion of beach and dune systems, undercutting of cliffed coasts, increased peak flows in coastal rivers and estuaries and damage to coastal infrastructure like piers, jetties, bathing boxes, breakwaters, sea walls and coastal roads. Damage to coastal structures will heighten safety concerns and the risk situation for managers and insurers will intensify. Increased erosion will provide new unconsolidated sediment into the coastal system that may require additional dredging if important navigation channels are to be maintained. Changed climatic regimes may have an impact on tidal flows in marine embayments and on water levels during storm surges.
In built environments volumes of stormwater reaching the coast are likely to increase in many regions, which will have an impact on the water quality of coastal estuaries and the near shore marine environment.
Coastal vegetation communities and estuarine and freshwater wetlands are shaped by the dynamic interplay of natural forces such as salt laden winds, shifting sands, storms and tidal influences. These forces of nature have created ecosystems which are sensitive to introduced change. For example, erosion from foot traffic and trampling can have a major impact on the coastal environment, and vegetation loss can take a long time to recover and require significant remediation efforts.
Coastal and marine structures are also constructed to provide infrastructure for industry, tourism and recreation. These structures can alter the natural coastal processes that then results in 'downstream' erosion, which requires active management. Human use and development along the coast continues to lead to serious declines in both marine and terrestrial flora and fauna.
Specific issues of major concern along the coast include:
- continuing fragmentation of habitat and consequent biodiversity loss;
- alteration of, and conflict with, ecological processes along the coast due to human development;
- weed and pest animal invasion causing landscape-scale changes to coastal environments;
- impacts from coastal catchments and coastal environments including deteriorating water quality and quantity;
- maintenance or improvement of environmental flows to waterways;
- the disappearance of some narrow strips of coastal Crown land in low lying areas; and
- the massive increase in establishment of exotic marine organisms (eg. the Northern Pacific Seastar (Asterias amurensis) which is principally found in Port Phillip Bay).
The naturally dynamic nature of the coastal environment has meant that it has always been important that decisions impacting on the future coastal environment be made with caution. With the impacts of climate change being modelled and better understood, the need to prepare strategies which allow for the widest possible range of future outcomes is even more important. Our growing understanding of climate change, coupled with the nature of coastal ecosystems that are sensitive to introduced change, points to the need for caution in decision making as a minimum and for efforts to protect or rehabilitate our coastal environment wherever possible.
