Dandenong Catchment Snapshot

1. Overview of catchment

2. Highlights of the catchment – natural values

3. Good wins (programs/projects)

4. Key Issues

Friday 24 August 2017

Overview of Catchment

‘Dandenong Catchment’ area ~ 882 km2

485 km rivers & creeks

Connection with Port Phillip

Major waterways include:

Dandenong Creek Boggy Creek Mordialloc Creek Kananook Creek Patterson River Monbulk/Ferny Creeks Eumemmering Creek Elster Creek

History

• Large swamplands

• Carrum b/n Mordialloc & Kananook

• 15km long, up to 8km wide

• Mid to late 1800’s Mordialloc & Seaford swamp drainage

• Patterson River cut 1879

• 1890’s diversions and drain construction at lower end connecting Dandenong Creek to Mordialloc Creek, Centre Swamp, Whatley’s and Eel Race drains

Change in Waterway Management Focus

• Secure water supply (e.g. Belgrave Lake 1893, Lysterfield 1929)

• 1890s Melbourne’s residents gradually sewered

• Flood protection

• Series of large floods (1904, 1934, 1937, 1952)

• Flood protection activities 1920s – 1950s

- Enlargement, straightening, concrete lining, piping of waterways

- Levee construction

- Retarding basins

- Pumps (e.g. Centre Swamp)

- Desnagging

• 1970s Point source pollution management (EP Act)

• 1980s minor wastewater treatment plants established to replace septics

• 1990s Biodiversity and stormwater treatment

1974 2017

Forested Areas and Parklands ~10%

Agriculture ~15%

Residential Areas ~60%

Rowville 1945

Rowville 2017

Commercial and Industrial Areas ~10%

Catchment – Environmental Values

Environmental Values:

• Birds

• Fish

• Frogs

• Macroinvertebrates

• Platypus

• Vegetation

Environmental conditions

Environmental values

Aquatic macroinvertebrates

Photos by John Gooderham and Edward Tsyrlin

Environmental Values – Macroinvertebrates

Based on aquatic macroinvertebrate community surveys since 1990s

Stream health highest in forested headwaters

Threats include:

- Urban stormwater (water quality and flow)

- Loss of instream and riparian habitat (vegetation, physical form)

- Industrial pollution

Environmental Values – Fish

12 freshwater species, 9 exotic species Several estuarine species, including black bream, yellow-eye mullet Nationally significant species: dwarf galaxias and Yarra pygmy perch Threats to fish species include: • habitat loss/degradation (instream and floodplain) • several large barriers to movement in the catchment • urban stormwater • Industrial pollution • pest fish e.g. Carp, Gambusia

Fish

Environmental Values – Frogs

Upper catchments rate higher than lower subcatchments,

Lack of data in some areas e.g. Monbulk, Ferny and Blind Creeks

Threatened species in the catchment: • Growling Grass Frog • Southern Toadlet

Threats include loss of floodplain habitat, loss of connectivity, pest species

Growling grass frog Southern Toadlet

Photos by Peter Robertson

Frogs

Banjo/Pobblebonk frog Spotted marsh frog

Striped marsh frog Southern brown tree frog

Common froglet

Photos by Peter Robertson

Catchment - Environmental Values – Platypus

• Since 1995 platypus can be found in upper catchments – Dandenong, Dobsons, Monbulk and Ferny Creeks

• Populations threatened and may be lost from upper Dandenong Creek (2011) and Ferny Creek (1996/97, but unconfirmed sightings)

• Threats include:

- urban stormwater (litter, food)

- loss of riparian vegetation

- loss of instream habitat

- Fragmentation/inbreeding

Upper Monbulk Lower Monbulk

Environmental Values – Birds

• 295 bird species recorded in the catchment

• 126 species riparian specialists expected to occur and condition good overall

• Edithvale-Seaford Wetlands

⁻ international significance for migratory shorebirds (sharp-tailed sandpiper >1% world population = Ramsar)

- drought refuge for waterfowl (e.g. Chestnut teal, grebes and coots)

- threatened species e.g. Australasian bittern (EPBC) and blue-billed duck (FFG)

• International ‘Important Bird Areas’ also cover ETP and Braeside Park e.g. Lewin’s rail

• Several Latham’s snipe locations throughout the catchment e.g. Tirhatuan Wetland

Australasian bittern

Sharp-tailed sandpiper

Blue-billed duck

Chestnut teal

Lathams snipe (Geoff Gates)

Lewins rail (Chris Tzaros)

Photos by John Barkla, Birdlife Australia

Environmental Values – Vegetation

• Forested areas of upper catchments have higher values

• Extensive land clearing = very low to moderate condition in many areas

• Notable areas include:

- Dandenong Ranges, Churchill, Lysterfield (remnant forest)

- Dandenong Valley parklands (riparian woodlands, billabongs, Tirhatuan wetland)

- Remnants of Carrum swamp (Edithvale-Seaford, Kananook, ETP, Mordialloc, Braeside) – aquatic herblands, swamp scrub, coastal banksia woodland

- Hallam Valley (remnant aquatic herblands, swamp scrub, plains grassy wetlands, grassy woodlands)

- The Pines and Langwarrin Flora and Fauna Reserves (heathland/grassy woodland)

• Weeds an ongoing threat e.g. Tradescantia, woody weeds, blackberry, gorse

• Extensive riparian revegetation effort by many groups and organisations has led to substantial improvements

Catchment– Social Values

Social Values

• Amenity

Expanded in new strategy

• Recreation

• Community Connection

Social Values: Amenity, Connection and Recreation

GOOD WINS - Projects/case studies

Overview of Catchment – Targets in the Current Strategy

Works Target Achieved Total

Km vegetation established 45 78 173%

Km of vegetation managed 633 779 123%

Km of stock exclusion fencing constructed 2 1.6 81%

Number of fish barriers removed 1 1.0 100%

Ha of aquatic habitat improved 25 134 536%

Working through our partnerships

with councils and maintenance of our

waterways to achieve stormwater

targets, through:

- Litter/debris removal

- Sediment removal

- Workshops with Council

- Living Rivers funding

Good Wins: Grants Programs and Capital Projects

Programs in Dandenong catchment include:

• Living Links • Community Grants • Stream Frontage Management Program • Corridors of green funding • Living Rivers Program • Melbourne Water Capital Works Projects

Good Wins: Wicks Reserve Bio-infiltration Basin

Good Wins: Goat Trial, Dandenong Creek, Vermont South

Good Wins: Habitat Improvement - Site of Biodiversity Significance, Wannarkladdin Wetland, Patterson Lakes

Good Wins: Dwarf galaxias and Yarra Pygmy Perch habitat restoration, Mid-Upper Dandenong Creek floodplain

Threats and opportunities

Dandenong Creek Headwaters

Values

• Catchment area not impacted by urbanisation.

• High value native vegetation, fish, macroinvertebrates, frogs, platypus and good water quality.

Threats

• Climate change and bushfires

• Alteration to flow regime with urbanisation

Opportunities

• Drought refuge management – manage and extend habitat for platypus.

• Sustainable development.

• Stormwater intervention works to manage stormwater flows.

Key threats – Climate change

Climate change impacts to waterways include:

• Reduced in total flows • Changes in flow seasonality • Increased cease-to-flow-period in intermittent streams • Increased frequency and duration of inter-annual droughts • Increased intensity of storm events

Key threats – urbanisation

• Urbanisation & conventional stormwater drainage has a negative impact on flow regimes. • High-intensity disturbance contributes to excessive erosion, loss of habitat & reduction in biodiversity. • High-frequency disturbance reduces resilience & reduces recovery potential.

Middle Dandenong Creek

Values

• Macroinvertebrates and fish present but degraded.

• Remnant vegetation and flood plain areas high value.

• Priority billabongs.

Threats

• Stormwater quality from urban and industrial areas.

• Altered flow regime and barriers to fish movement

• Increased frequency of scouring flows.

Opportunities

• Stormwater intervention works to manage stormwater flows.

• Reconnection of flood plain habitat.

Eumemmerring and Hallam Valley

Values

• Vegetation, fish, macroinvertebrates, frogs and water quality.

• Vegetation and shallow wetlands important retention and treatment stormwater run off.

Threats

• Future urban development and climate change.

• Stormwater quality and alteration to flow regime.

Opportunities

• Stormwater intervention works to manage stormwater flows.

• Urban growth planning with water sensitive outcomes.

Lower Dandenong and Kananook Creek

Values

• Vegetation, frogs and bird communities.

• Natural and constructed wetlands (shallow groundwater)

Threats

• Future urban development and climate change.

• Stormwater quality and alteration to flow regime.

• Stormwater quality from urban and industrial areas.

Opportunities

• Stormwater intervention works to manage stormwater flows.

• Urban growth planning with water sensitive outcomes

Other Issues: Litter and pest plants and animals