Westernport catchment

The Westernport catchment covers 3,721 square kilometres and contains 2,232 kilometres of rivers and creeks. The landscape is varied and includes hilly regions near the Bunyip State Park and Strzelecki Ranges, the flat, undulating terrain of the former Koo Wee Rup swamp, and the marine environment of Western Port and its islands.

Westernport catchment areaMost of the catchment is modified to support rural and green wedge land uses, though there are still some significant environmental values:

  • primary industries include dairying, beef production, poultry, horticulture and quarrying
  • urban, industrial and tourist areas and lifestyle and hobby farms make up a smaller proportion
  • some forested areas remain in the upper catchment, French Island and the Mornington Peninsula

Significant features of the catchment include surface and groundwater springs, which support many streams and wetlands. The marine ecosystem within Western Port is also of regional, national and international importance and supports mangrove, saltmarsh, seagrass, reef and soft seabed habitats.

Drainage and flood minimisation are significant challenges of the low-lying, former swamps, which were drained in the 1800s to allow settlement and farming.

The Westernport catchment contains five sub-catchments:

Upper Bunyip and Tarago system

The major waterways within this system are:

  • Bunyip River
  • Tarago River
  • Cannibal Creek
  • Labertouche Creek

These waterways are largely within State Forest and have remained in a mostly natural state. Upper forested and rural waterways have multiple uses such as water supply, farming, lifestyle and recreational activities like fishing and picnicking.

The community values the significant animal species present in this system, including azure kingfishers, Australian grayling, Warragul borrowing crayfish and a healthy platypus population. They also value the amenity associated with agricultural and recreational areas.

Challenges for waterway health include managing environmental flows, connecting habitat along waterways and balancing water supply and rural community access and use.

Condition of key values

​Key value Condition Details
​Current: very low The lower Tarago River has the catchment’s highest known abundance of platypus, but they have significantly declined over the past 200 years – a key reason being the drought over the past decade.
20-year: low
Long-term: moderate
​Current: very high The variety and proportion of native fish is very high. Works to maintain their habitat and passage aim to maintain this condition.
20-year: very high
Long-term: very high
​Current: moderate Frog populations have a moderate diversity and have been consistent over the past decade. We aim to improve their condition by improving floodplain habitat.
20-year: high
Long-term: very high
​Current: moderate* Streamside bird variety and proportion of native species is moderate. We aim to maintain and eventually improve this condition by focusing on habitat improvements.
20-year: moderate
Long-term: high
​Current: moderate The upper reaches of waterways are largely within state parks; however vegetation declines in the lower reaches. The overall condition is moderate, with works aiming to improve this over the long-term.
20-year: high
Long-term: very high
​Current: high Macroinvertebrates are in high condition in forest waterway reaches, with some decline in rural sections. Protecting and improving water quality and habitat aims to raise this condition to very high.
20-year: very high
Long-term: very high
​Current: high** High amenity values are still provided and reserved through natural forests, picnic areas along rivers and streams and scenic views along waterway corridors.
20-year: high
Long-term: very high

* Streamside birds only - does not include wetlands
** Limited data used to determine this rating

 

Lower Bunyip, Lang Lang and Bass system

The major waterways within this system are:

  • lower Bunyip River
  • Lang Lang River
  • Bass River
  • Yallock Creek
  • Little Lang Lang River
  • Pheasant Creek
  • O’Mahoneys Creek

Estuaries including the Bunyip, Lang Lang and Bass rivers support internationally recognised wetland habitat and animals. They also contain important plant communities like saltmarsh and mangroves, which are valued by the community and vital for marsh birds and the southern brown bandicoot.

Waterways are mainly rural, and used for a variety of purposes like water supply, flood mitigation, townships, primary production and lifestyle, recreational use and supporting plant and animal species such as platypus and the Australian grayling. The challenge for waterway health in this system is balancing these multiple objectives. 

Condition of key values

​Key value Condition Details
​Current: very low Platypus numbers have declined due to significant alteration and disturbance of waterways. The small population in the Lang Lang River is critically low after many years of drought. Our works aim to stabilise this population and improve it over the long term.
20-year: very low
Long-term: moderate
​Current: high Fish populations are in high condition, and we aim to maintain this over the next 20 years. Improving habitat and fish passage may see migratory species like smelt and lamprey recorded again.
20-year: high
Long-term: very high
​Current: very high Frog diversity is very high, and our floodplain works will focus on maintaining this condition over the next 20 years and beyond.
20-year: very high
Long-term: very high
​Current: very low* Streamside birds are in very low numbers and variety. We aim to raise this condition through habitat improvement works, but the long-term condition is limited by the lack of large forested areas as habitat.
20-year: low
Long-term: moderate
​Current: very low** Vegetation has been subject to widespread clearing and is in very low condition. Streamside revegetation works aim to improve this, but levies and the need to maintain waterways' hydraulic capacity place limits on the achievable long-term condition.
20-year: moderate
Long-term: moderate
​Current: moderate Macroinvertebrates are in moderate condition, though we aim to raise this by improving habitat and water quality through streamside vegetation and stormwater management.
20-year: high
Long-term: high
​Current: low Some waterways have been dramatically altered and amenity is low. Vegetation improvements will increase this moderate in the long term, but limited public land and access to waterways will restrict the overall gain.
20-year: low
Long-term: moderate

* Streamside birds only - does not include wetlands
** Limited data used to determine this rating

 

Cardinia system

Historically, the major waterways within this system did not exist or were disconnected from Western Port by the former Koo Wee Rup Swamp. These waterways are:

  • Cardinia Creek
  • Toomuc Creek
  • Deep Creek
  • Ararat Creek
  • Langwarrin Creek
  • Clyde Creek

Estuaries like Cardinia Creek support internationally recognised wetland habitat and animals, while Cardinia Reservoir is located high in the catchment.

Waterways in this system support a variety of uses including flood mitigation, recreational use and significant animals like platypus, dwarf galaxias, growling grass frogs and southern brown bandicoots. Another special feature is plant communities of high conservation significance, including swampy streamside woodland, coastal saltmarsh and mangroves. These, together with recreational areas like Cardinia Reserve and marine national parks, are highly valued by the community.

Challenges for waterway health include managing urban growth and balancing multiple objectives such as flood mitigation, habitat protection and social uses.

Condition of key values

​Key value Condition Details
​Current: very low Platypus became locally extinct in the late 1990s. Ten platypus were released into Cardinia Creek in 2004 and 2007 and have been recorded breeding. Vegetation works aim to improve habitat over the long term.
20-year: very low
Long-term: low
​Current: high Fish populations are in high condition. Works to improve fish passage, flows and habitat aim to increase this rating over the long term.
20-year: high
Long-term: very high
​Current: very high The variety of frog species is very high. Habitat improvement works aim to maintain this condition.
20-year: very high
Long-term: very high
​Current: very low Native bird communities have declined due to the recent drought, and are in very low condition. Floodplain vegetation and habitat works aim to improve this, but recovery is limited by the lack of opportunity to create large areas of connected habitat.
20-year: low
Long-term: moderate
​Current: low Vegetation is in low condition, though the upper reaches of Cardinia Creek have some relatively intact vegetation. Works aim to improve this over the next 20 years and beyond.
20-year: moderate
Long-term: high
​Current: moderate Macroinvertebrates are in moderate condition, but expected to improve within the next 20 years in response to water quality improvement actions.
20-year: high
Long-term: high
​Current: moderate* There is limited data to assess the perceptions of amenity in this system. It is rated moderate and expected to increase as vegetation improves.
20-year: high
Long-term: very high

* Limited data used to determine this rating

 

Mornington Peninsula system

Most waterways are small creeks flowing into Western Port, Port Phillip Bay or Bass Strait. The major waterways are:

  • Main Creek
  • Chinamans Creek
  • Dunns Creek
  • Merricks Creek
  • Balcombe Creek
  • Watsons Creek

Significant wetlands include Tootgarook Swamp, the Coolart wetlands and the Bittern Coastal Wetlands. Merricks and Balcombe creek estuaries also provide important habitat for macroinvertebrates and native fish.

Several significant animal species are found within this system, including the swamp skink, southern toadlet, river blackfish, dwarf galaxia and growling grass frog, as well as short-tailed shearwaters (mutton birds) and powerful owls that are valued by the community. Recreational areas like Point Leo also have special value.

Challenges for waterway health include managing the impacts of urbanisation, protecting important environmental habitat and enabling social access and use.

Condition of key values

​Key value Condition Details
​N/A Although some areas provide suitable habitat, our monitoring program has not recorded any reliable platypus sightings or captures since it began in 1995. This may relate to the historic fragmentation of habitat.
​Current: high Fish populations have been increasing in abundance and species richness since the 1990s. A range of on-ground works will further improve this rating.
20-year: very high
Long-term: very high
​Current: very high Frog populations are very highly diverse, wih all expected species being observed. Ongoing works aim to maintain this condition.
20-year: very high
Long-term: very high
​Current: low Bird ratings are low, though works aim to improve the variety and proportion of native species. Their long-term outcome is limited as even with all waterways vegetated, the lack of connection to large habitat areas will constrain the abundance of populations.
20-year: moderate
Long-term: moderate
​Current: low Vegetation has been highly modified and is in low condition. Fragments of remnant vegetation in moderate condition still exist along waterways, and works aim to improve this.
20-year: moderate
Long-term: high
​Current: moderate Macroinvertebrates are in moderate condition and have been stable since the 1990s. Vegetation and water quality improvements are aiming to raise this to high.
20-year: high
Long-term: high
​Current: low Amenity is low, though many of the lower estuarine reaches are valued. Most waterways flow through agricultural land although some are protected in national parks.
20-year: moderate
Long-term: high

 

French and Phillip Islands system

The major waterways within French and Phillip islands are:

  • Tankerton Creek
  • Redbill Creek
  • Mosquito Creek
  • Saltwater Creek
  • Swan Lake Drain

Rhyll Inlet and other estuaries support internationally listed wetlands, habitat and animals, especially migratory wading birds.

These small waterways support a variety of uses including townships, farming, recreation and some significant plant and animal species. The community especially values the migratory shorebirds, saltmarsh communities and recreational areas in this system.

Challenges for waterway health include managing the impacts of urbanisation, protecting important existing environmental values and enabling social access and use.

Condition of key values

​Key value Condition Details
​N/A Platypus populations have not been recorded. Waterways are unlikely to have supported them since the islands were separated from the mainland due to lack of suitable habitat.
​Current: very high Fish communities are in very high condition, with a noteworthy absence of introduced fish (apart from mosquito fish). We aim to maintain this condition.
20-year: very high
Long-term: very high
​Current: low* Frog diversity is low, based on the limited data available. We aim to improve this over the next 20 years.
20-year: moderate
Long-term: high
​Current: very low** Streamside birds are in very low condition, though works aim to improve this. Limited waterways on the island constrain the variety of streamside birds, and so the long-term target is low.
20-year: low
Long-term: low
​Current: low* Vegetation condition is generally low, though areas of good remnant vegetation exist within parks and reserves.
20-year: moderate
Long-term: high
​Current: low Macroinvertebrates are highly dependent on water quality, which is threatened by increased urban development - especially on Phillip Island. Works aim to stabilise and improve this condition over time.
20-year: low
Long-term: moderate
​Current: moderate* Waterway amenity is often secondary to coastal amenity, though there are a variety of waterways for the community to enjoy. Based on limited data, amenity is rated as moderate though vegetation works aim to maintain and improve this in the long term.
20-year: moderate
Long-term: high

* Limited data used to determine this rating
** Streamside birds only - does not include wetlands

Did you know?

More than 2,000 Aboriginal sites have been recorded in the Westernport catchment, most being artefact scatters and shell middens near waterways.

 

Key facts

  • Area:
    3,721 square kilometres
  • Average rainfall:
    691mm (Phillip Island) to 946mm (Tarago Reservoir)
  • Traditional owners:
    Wurundjeri, Boon Wurrung, Bunurong and Gunai Kurnai people


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