Where the rivers meet the seas

Estuaries are the places where rivers and the sea meet. They are typically semi-enclosed coastal bodies of water with a connection with the open sea and within which sea water is measurably diluted with fresh water draining from the land and waterways that feed it.

Estuaries support a range of distinctive aquatic and terrestrial plants and animals. They provide core breeding and feeding areas for waterbirds, and spawning and nursery areas for many fish species.

Vegetation adjacent to estuaries (such as mangroves, seagrasses and saltmarshes) help to maintain water quality, assist with nutrient cycling, and provide a buffer to catchment-derived sediments, nutrients and other pollutants entering the marine environment. Estuarine ecosystems are highly complex and dynamic. Since estuaries are at the end of waterways, their condition is affected by activities occurring upstream in the catchment. Where the condition of catchments, rivers or estuaries is poor, there are likely to be impacts on the marine receiving waters and coastal areas. Similarly, the condition of the marine environment can also impact the health of estuaries.

Humans have long valued estuarine areas. The region’s estuaries are important to Traditional Owners and many contain ancient sites of cultural significance.

Sheltered estuarine waters across Victoria were also among the first areas to be settled by non-Indigenous people. Many estuaries in the late 1800s and early 1900s were transport and fishing hubs, which supported prosperous industry and ports. These early settlements have since developed into some of the region’s most densely populated areas. Estuaries are valued for recreational and commercial fishing, tourism, recreation, port trade and boating.