The wetland group is divided into the northern Edithvale Wetland, and the southern Seaford Wetland, by the Patterson River and the Patterson Lakeshousing development. They lie about 30 km south-east of Melbourne City Centre, close to the eastern shore of Port Phillip, between the coastal Nepean Highway to the west and the Frankston and Mornington Peninsula Freeways to the east, and are largely surrounded by houses and golf courses. Both wetlands are seasonal floodplain systems deriving most of their water as runoff from their local catchments, the areas of which are no more than 500 ha each. They are mainly freshwater wetlands underlain by peat beds that limit the entry of salinegroundwater. They are essential components of the regional drainage system in receiving, retaining and naturally treating stormwater and other surface runoff, thus protecting surrounding areas from flooding as well as helping to protect the water quality of Port Phillip. Hydrological management of the wetlands is aimed at enhancing their natural values and controlling the ingress of saline groundwater.
History
Before European settlement of the area around Port Phillip in the mid-19th century, the historic Carrum Carrum Swamp stretched from what is now Mordialloc in the north to Frankston in the south. The 4000 ha swamp's freshwater and brackish wetlands supported many animals and plants, including brolgas and magpie geese which are now locally extinct. During the second half of the 19th century the swamp was progressively drained for farming. In 1879 the Patterson River, an artificial waterway, was cut through the swamp to the coast as part of the drainage program. The remaining wetland areas were retained to provide critical flood protection. They are the largest natural wetlands of their type left in the catchments of Port Phillip and Western Port.
Ramsar listing
The wetlands were listed on 29 August 2001 under the Ramsar Convention, as Ramsar site 1096, Australia's 11th site, in recognition of their international importance, and specifically because they:
are the last remaining examples of the Carrum Carrum Swamp, containing a variety of permanent and seasonal, freshwater and saline wetlands,
support populations of the Australasian bittern, considered to be of state significance and threatened in Victoria, and
They are also considered to be of exceptional significance as examples of cost-effective management of wetlands in an urban setting to provide conservation benefits, manage storm water, and encourage environmental education and research.
Flora and fauna
Plants
The wetlands contain 14 ecological vegetation types. Three of state significance are plains sedgey wetland, tall marsh dominated by common reeds, and brackish aquatic herbland. There are several regionally significant populations of plant species, such as southern water-ribbons, only previously known in the state from western Victoria; as well as one of state significance – the large river buttercup. A dryland vegetation association present, though degraded by invasive weeds, is river red gum dune woodland, a community that has not been recorded elsewhere in Victoria and is of high conservation significance.
The Edithvale Wetland is managed by Melbourne Water, while the Seaford Wetland is jointly managed by Melbourne Water and the City of Frankston. Public amenities include a bird hide at the Edithvale Wetland with education displays, as well as walking and bicycle tracks around both wetlands for birdwatching. The bird hide is accessible from Edithvale Road, staffed by volunteers from the Friends of Edithvale-Seaford Wetlands, and open from 1300 to 1700 on Sundays. The hide was closed in early 2010 due to structural problems. It reopened in August 2016.
