The Finniss River drains part of the east side of

Fleurieu Peninsula The Fleurieu Peninsula () is a peninsula in the Australian state of South Australia located south of the state capital of Adelaide. History Before British colonisation of South Australia, the western side of the peninsula was occupied by the K ...

into Lake Alexandrina in

South Australia South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest of Australia's states and territories ...

. It is part of the

Murray–Darling basin The Murray–Darling basin is a large geographical area in the interior of southeastern Australia, encompassing the drainage basin of the tributaries of the Murray River, Australia's longest river, and the Darling River, a right tributary of ...

. The Finniss River starts east of Yundi and flows roughly east to its mouth in the Goolwa Channel of the lower

Murray River The Murray River (in South Australia: River Murray) (Ngarrindjeri: ''Millewa'', Yorta Yorta: ''Tongala'') is a river in Southeastern Australia. It is Australia's longest river at extent. Its tributaries include five of the next six longest r ...

, opposite

Hindmarsh Island Hindmarsh Island (Ngarrindjeri: Kumerangk) is an inland river island located in the lower Murray River near the town of Goolwa, South Australia, Goolwa, South Australia. The island is a tourist destination, which has increased in popularity si ...

. It supports a wide range of flora (both natural and introduced weed species) and macroinvertebrates despite much of the catchment being cleared and grazed. During the 2006–2010 drought, low water levels in Lake Alexandrina and the outflows of the Finniss River and Currency Creek exposed acid sulfate soils which would normally be submerged. Temporary flow regulators were installed in August–September 2009 across the Goolwa Channel to maintain the water level to keep these soils wet to prevent more acid being leached out. They were partially removed in September 2010 and completely by October 2012. Watchalunga Nature Reserve, established in 2015, is in the lower reaches of the Finniss River, where it provides

swampland A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in ...

habitat for the Mount Lofty Ranges Southern Emu-wren, an

endangered species An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inv ...

, and the

southern bell frog The growling grass frog (''Ranoidea raniformis''), also commonly known as the southern bell frog, warty swamp frog and erroneously as the green frog, is a species of ground-dwelling tree frog native to southeastern Australia, ranging from sout ...

, which is a

threatened species Threatened species are any species (including animals, plants and fungi) which are vulnerable to endangerment in the near future. Species that are threatened are sometimes characterised by the population dynamics measure of ''critical depensa ...

References

Rivers of South Australia Fleurieu Peninsula {{SouthAustralia-geo-stub