Victoria’s water environments are diverse and are among our most valuable assets. They are home to a huge variety of creatures, from tiny plankton to fish, dolphins, birds and whales, including some that are unique to our state and others that migrate to Victoria each year from across the globe.
Estuaries are where rivers meet the sea. They undergo substantial salinity change due to the mixing of fresh water with seawater. They may be permanently or periodically open to the sea, with salinities that vary from almost fresh to very saline. Environmental condition may be stable over long periods of time or change frequently or rapidly. Estuaries are, therefore, complex and highly variable environments that often appear to be unpredictable. The Gippsland Lakes form a key estuary where EPA regularly monitors water quality.
Since estuaries are at the bottom end of catchments, they are subject to all the impacts on the catchment and most estuaries could be considered to be potentially at risk. Few would be considered to be in a natural or near-natural condition.
Victoria’s three largest embayments – Port Phillip Bay, Western Port and Corner Inlet – are of great social, economic and environmental value to Victoria. But sustaining their health is challenged by the combined pressures of urban and industrial development , industrial point source discharges, excess in nutrient and sediment loads, pollutants, introduced species impacting on biodiversity and the potential effect of climate change.
EPA’s focus has been on monitoring and protecting these marine systems as they can be highly sensitive to these stressors.
Victoria’s open coasts are a dynamic environment that cover some 2000 kilometres and extend 3 nautical miles offshore. They include a wide range of natural habitats and a variety of fauna, from microscopic plankton to large sea mammals.
These coastal waters are also important for the economic and social opportunities they provide. Sometimes these competing needs can cause impacts on the environment.
Key threats to coasts include marine pests, pollution from catchment run-off, industry, shipping, as well as coastal urban development and climate change. EPA monitors the threat of pest incursions through their ballast program and undertakes impact investigations of spills when they occur.
The health of a river’s catchment areas – the area from which water drains into the river – has a direct impact on the health of all our water environments.
The consequences of deteriorating environments are often immediate, serious and costly. Better and more integrated management of catchment activities can minimise impacts and improve the quality of water environments.
Wetlands include natural waterbodies like lakes and billabongs, but also can be built by humans – including farm dams, sewage treatment systems and stormwater basins. They are often diverse and important ecosystems and some of Victoria’s wetlands are internationally recognised.
Many wetlands are susceptible to degradation because of their small size and the amount of pollution that can flow into them.
Groundwater is the water held in sediment and rocks below the surface of a catchment. It is an important ecosystem, with many organisms living in groundwater systems. Many rivers and wetlands are dependent on groundwater when it reaches the earth’s surface.
The quality and quantity of groundwater are important because of its use for agriculture, industry and as a source of water for human consumption. Major threats to groundwater are the over use of the water and pollution from contamination by activities by humans.