Water

Draft for Consultation

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The ‘water theme’ of this Regional Catchment Strategy includes the rivers, wetlands, water resources, and groundwater of East Gippsland, including the aquatic biodiversity supported by these freshwater systems. Our region is one of the few places on mainland Australia where continuity of natural ecosystems from the alps to the sea still exists. 

Our water dependant values… a snapshot

The waterways of East Gippsland support significant ecological, social and cultural values. Fresh water is critical to the productivity of the region and our aquatic habitats support a large number of threatened species that depend on these ecosystems.

The rivers of East Gippsland rise in the Great Dividing Range, and flow generally south to discharge into Bass Strait. Rivers in the east through smaller estuaries and inlets to discharge directly to the sea, whilst the tributaries of the Gippsland Lakes discharge to lake King, before water flows to the sea through Lakes Entrance. 

Many of the wetlands within the region are associated with the alpine areas and coastal wetlands (see coastal theme). There are a small number of freshwater floodplain inland wetlands, including Macleod Morass, which is part of the Gippsland Lakes Ramsar Site. 

Fertile lower floodplains, including the Mitchell River in particular, are utilised for agriculture including irrigated horticulture operations.

The waterways of East Gippsland are valued by the local community, visitors to the region and the broader Australian community.

Genoa River
Genoa River

The waterways of East Gippsland support significant ecological values including a large number of threatened species with 350 species of plant, 44 species of bird, 11 species of frog, 9 species of fish and 1 mammal species that are dependent on these aquatic ecosystems. 

Nicholson River at Deptford
Nicholson River at Deptford

The major rivers of the region are largely unregulated with the only major storage in the region located on the Nicholson River, although there is a major storage on the Snowy River upstream of East Gippsland in NSW. As a result, most of the river systems have low modifications to the flow regime and support significant natural values.  East Gippsland contains several rivers which have no barriers to fish passage, including the Benedore, Thurra, Suggan Buggan and Berrima Rivers, all of which are listed on the Directory of Important Wetlands in Australia. These river systems also have few or no introduced fish species, which when coupled with connectivity from headwaters to the sea, results in a high diversity and abundance of native fish. Many of the rivers of East Gippsland support the nationally endangered Australian grayling as well as a diversity of riparian and aquatic plants. The pristine nature of many of the rivers in East Gippsland enhances their ecological values and provides unique habitat for a variety of species. For example, the Wongungarra River contains the only unmodified habitat for endangered spotted tree frog. 

Figure 1: Waterways of East Gippsland

Waterways of East Gippsland

The peatlands of the alpine region of East Gippsland are rare in Australia. These are permanently wet sites that contain at least one species of Sphagnum in areas above 1000 metres in elevations. They perform important functions, filtering nutrients and sediments, and maintaining good water quality in streams and groundwater. They support a diversity of aquatic flora and fauna including threatened species like alpine pennywort, alpine bog skink, alpine water skink, and alpine spiny crayfish, as well as the nationally vulnerable alpine tree frog. Significant alpine wetlands in East Gippsland include the nationally important Nuniong Plateau Peatlands and the threatened ecological community ‘Montane Swamp Complex’, which comprises seven small sites (total of 44 hectares) on the tributaries of the western headwaters of the Tambo River.

The waterways of East Gippsland support 27 different ecological vegetation communities (EVCs) that are considered river or wetland dependent. Combined these cover an area of almost half a million hectares and include areas of alpine bog, extensive riparian forests and woodlands and large areas of wet or damp forest (Table 1).

Table 1: Waterway dependent ecological vegetation classes in East Gippsland

EVCHectares
Alpine Fen20
Aquatic Herbland/Plains Sedgy Wetland Mosaic44
Billabong Wetland Aggregate130
Cool Temperate Rainforest2690
Cool Temperate Rainforest/Warm Temperate Rainforest Overlap256
Damp Forest292968
Deep Freshwater Marsh1026
Dry Rainforest/Warm Temperate Rainforest/Gallery Rainforest/Riparian Shrubland/Riverine Escarpment Scrub/Blackthorn Scrub Complex183
Floodplain Reedbed461
Montane Riparian Thicket1082
Montane Riparian Woodland3340
Plains Grassy Wetland30
Riparian Forest24104
Riparian Scrub190
Riparian Scrub/Swampy Riparian Woodland Complex18988
Riparian Shrubland1941
Riverine Escarpment Scrub4692
Sedge Wetland175
Snowpatch Grassland13
Sub-alpine Wet Heathland562
Swamp Scrub2653
Swamp Scrub/Plains Sedgy Wetland Mosaic3
Swampy Riparian Woodland253
Warm Temperate Rainforest8533
Wet Forest107502
Wet Heathland8593
Wet Swale Herbland790

The waterways of East Gippsland are valued by the local community, visitors to the region, and the broader Australian community. The health of these waterways underpins many aspects of regional tourism, jobs and investment, particularly in coastal areas such as the Gippsland Lakes. Fishing, swimming, camping and boating are all popular in East Gippsland.

Rafting down the Snowy River
Rafting down the Snowy River

Although water extraction for consumptive use is low in East Gippsland, compared to many other regions in Victoria, there are licensed extractions from the river systems. This includes for industrial and agricultural use (e.g. irrigation from the Lower Mitchell) as well as for stock and domestic purposes. 

Groundwater extraction in East Gippsland is generally low and the only groundwater management area is Orbost. There is also extraction of groundwater outside of the management units, with Lindenow and Mallacoota urban water supply and the agricultural areas along the Mitchell floodplain extracting water for consumptive use. Groundwater is also extracted in areas across the Redgum Plains to the east of Bairnsdale to support irrigated agriculture.

Despite the pristine nature of much of East Gippsland, waterways of the region are still subject to threatening processes. This includes the impacts of pest plants and animals, climate change and associated hotter and drier conditions directly impacting water regimes, as well as increasing risks from bushfires.  

Increased temperatures and decreased rainfall will result in a decrease in surface water and river flows. Rivers in East Gippsland have already experienced a decline in surface water availability of between 10 and 14 % (1997 to 2018 compared to the long-term historical average[1]) and will continue to decline under future climatic conditions. This has implications for plants and animals that rely on freshwater aquatic habitats, with a decrease in wetland area and an increase in the area and extent of dry periods in rivers and wetlands. A loss of connectivity between rivers, wetlands and the sea will impact on native fish, many of which rely on migration to complete their lifecycles. Decreased durations of inundation in wetlands will impact on waterbirds, frogs and invertebrates and may result in reduced populations if wet periods are too short for breeding cycles to be complete. Water quality in riverine pools and drying wetlands will decline as salts and nutrients concentrate in smaller pools of water. This can lead to conditions that are beyond the tolerance of fish and other aquatic biota and increase the severity of algal blooms. There will also be effects on consumptive use, with decreases in water availability occurring at the same time that there is increased demand for domestic and agricultural water supplies during hotter and drier periods.

In the forested uplands of the region, one of the major threats to waterway values are invasive plants and animals. Alpine peatlands and upland pristine streams are at extreme risk from deer and feral horses, with hard hooves causing significant and often irreversible damage to fragile peat communities. Willows and non-woody weeds also pose a threat to these communities, with invasion of willows following bushfire of particular concern. Climate change (hotter and drier conditions) can have major impacts to alpine peatlands and the associated increase risks from bushfires are significant. Alpine peatlands are highly vulnerable to fire and need to be protected from fuel reduction burning and associated traffic and machinery.

Damage to sensitive alpine country
Damage to sensitive alpine country

In the Snowy River, altered flow regimes have significant effects on waterway health. Almost 90% of the flow from the Snowy River is extracted upstream of East Gippsland and the reduction in flows has resulted in changes to the river channel and alterations to the ecology of the river system.  

On the lower reaches of rivers, where there are more settlements and agricultural activity, clearing of riparian land and loss of native habitat is considered a significant threat. Stock access to waterways increases erosion and decreases water quality and impacts on riparian vegetation in lowland river reaches. Disturbance of vegetation and waterways allows the establishment of invasive plant species in these environments. Feral pigs, goats, and deer all pose a threat to waterway values and increased introduced predators such as foxes and cats impact the animals that are dependent on the aquatic environment for habitat. 


[1] Department of Environment, Land, Water and Planning 2020, Long-Term Water Resource Assessment for Southern Victoria, State of Victoria, Melbourne.

Wetlands

There is limited information on the condition of wetlands in the East Gippsland region. Index of Wetland Assessments completed in 2009 and 2010, cover a small number of floodplain and alpine wetlands and indicate that while the alpine wetlands are largely in good or excellent condition, the floodplain wetlands are generally in moderate condition overall (Table 2). The pristine catchment conditions and largely unmodified hydrology in alpine wetlands maintain good ecological condition, while higher catchment pressures and altered hydrology are affecting the small number of wetlands assessed in lowlands. 

Table 2: Index of Wetland Condition assessments for wetlands in East Gippsland (2009 and 2010). 

WetlandCatchmentPhysical FormHydrologyWater PropertiesSoilsBiotaOverall
McLeod Morass920201519.511.87
Deep Water Morass4.561017613.586
Lindenow Wildlife Sanctuary4.516101711.511.276
Alpine 11820201714.5128
Alpine 2201820171718.69
Alpine 314.52020201918.69
Alpine 4202020171916.89
Alpine 520201017913.17
Alpine 62018201511.518.159
Freshwater meadow6.511.75517116.335

Wetland extent has been mapped from the herbaceous cover of native plant species (Figure 2). This indicates a decline in seasonal freshwater wetland vegetation extent in the region over the past 35 years. The area of open water, however, has largely remained stable over the same time period (Victorian Land Cover Time Series: DELWP). 

Figure 2: Change in extent of wetland vegetation cover (hectares) in the East Gippsland Region.
Source: Victorian Land Cover Time Series (DELWP).

Change in extent of wetland vegetation cover
click figure to view full size

Rivers

Condition of rivers in East Gippsland was assessed as part of the state-wide 2010 Index of Stream Condition. The majority of rivers in the region were in excellent or good condition, ranging from over 95% of river length in far east Gippsland to just under 70% of rivers in the Snowy and Tambo Basins (Figure 3). The rivers of Far East Gippsland scored highly across most of the sub-indices, while in the remaining river basins, not all sub-components fared the same. In the Snowy Basin, altered hydrology, largely due to upstream extractions has reduced the condition of the river, although water quality remains in largely good condition. In the Tambo, average water quality was lower, and in the Mitchell, there were lower average scores for physical form (Figure 4).

Figure 3: River length (%) in condition categories for the river basins in East Gippsland.
Source: the Third Index of Stream Condition (DEPI 2013).

River length in condition categories for the river basins in East Gippsland
click figure to view full size

Figure 4: Average condition scores (out of 10) for each of the sub-components of the Index of Stream Condition for the river basins in East Gippsland.
Source: the Third Index of Stream Condition (DEPI 2013). 

Average condition scores (out of 10) for river basins
click figure to view full size

Average river inflows in East Gippsland vary considerably from year to year. In the last two decades, this has ranged from a high of over 350 millimetres in 2012 to just 71 millimetres in 2019 (Figure 5). This is, however, tightly coupled to patterns in rainfall across the region. 

Figure 5: Annual river inflow (mm) and rainfall (mm) in the East Gippsland Region over time.
Source: Australia’s Environment Explorer (ANU-WALD).

Annual river inflow and rainfall in the East Gippsland
click figure to view full size

Trends in riparian condition from 2011 to present illustrate the effects of riparian restoration works in East Gippsland (Figure 6). In the Far East of the catchment, in particular there have been consistent improvements in riparian condition over the past decade. While the pattern is less clear in the other three river basins, there is evidence that fencing, stock management and removal of willows and other weeds is having a positive effect on river health. 

Figure 6: Proportion of riparian sites assessed in condition classes across East Gippsland from 2011 to 2020.

Mitchell Basin

Mitchell Basin riparian condition assessment
click figure to view full size

Snowy Basin

Snowy Basin riparian condition assessment
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Tambo Basin

Tambo Basin riparian condition assessment
click figure to view full size

Far East Basin

Far East Basin riparian condition assessment
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Groundwater

Changes in groundwater level can be tracked through the State Bore Monitoring Network. While the majority of the bores in East Gippsland indicate stable water levels, there are areas on the Red Gum Plains, to the west of Bairnsdale where water level trends are declining (e.g. Bore number 77947; Table 4). This reflects the relatively higher levels of groundwater extraction for consumptive use in this region.

Table 4: Groundwater level (m) monthly averages and trends in active SOBN bores in the East Gippsland Region.

BoreYearMarchJuneSeptemberDecember
144467 (Bete Bolong)20146.26.36.1
20156.365.55.6
20165.85.55.4
20176.95.75.55.4
20186.25.6
20196.15.65.15.6
20206.25.755.4
Groundwater trend levelStableStableDecliningStable
65762 (north of Blonde Bay)201420.6320.2420.1820.33
201520.3520.1920.120.14
201620.2520.1820.0720.18
201720.3220.2620.2420.34
201820.5520.5320.4362.29
20192120.6920.83
202020.49
Groundwater trend levelStableStableStableStable
56545 (Lindenow)201438.1438.1738.1938.17
201538.2138.1538.0838.14
201638.2538.0738.1638.16
201738.338.338.238.32
201838.2538.2838.21
201938.5
202038.47
Groundwater trend levelStableStableStableStable
77947 (Perry Bridge)201430.2529.3128.1328.92
201530.3629.3828.0728.42
201630.3629.6528.1628.29
201731.0930.3629.3429.49
201830.3330.9729.6930.855
201930.85
202031.430.8829.8331
Groundwater trend levelIncreasingIncreasingIncreasingIncreasing

Theme - Water

Water – improving the condition of the Alpine Peatlands in the Wonnangatta-Moroka and Dargo High Plains areas

Current State
(2021)

Most of the peatlands in the Wonnangatta-Moroka area are in good condition but some have been affected by weeds, particularly willows, vehicle and walking tracks (that have affected water flows into and out of peatlands) and damage by pest animals such as deer.

Medium-term
Outcomes (2027)

Alpine peatlands currently in good condition will remain in good condition, through the protection of altered hydrology and pest plants and animals.

Alpine peatlands are mapped and protected from altered hydrology and pest plants and animals.

Long-term
Outcomes (2027)

Targeted improvement of 75% (615 hectares) of peatlands in the Wonnangatta-Moroka areas will be protected in the current good condition.

The remaining 25% (205 hectares) of peatlands restored from the current levels of medium or poor condition to good condition.

Theme - Water

Water – improving the condition of the Mitchell, Nicholson and Tambo Rivers

Current State
(2021)

Mitchell, Nicholson and Tambo rivers are free of willows.

Some sections of waterway have continuous native vegetation riparian corridors with stock excluded.

Medium-term
Outcomes (2027)

Waterways are maintained as free of willows, and ongoing surveillance is undertaken for new and emerging weeds in remote tributaries.

Continuous native vegetation riparian corridors with stock excluded along priority reaches.

Long-term
Outcomes (2027)

Rivers and tributaries are maintained as free of willows and no new and emerging weeds are established.

Continuous native vegetation riparian corridors along all reaches of river, with stock excluded.

Theme - Water

Water – managing salinity, nutrients and sediments

Current State
(2021)

Loads of nutrients entering the system are largely a result of western river inflows, although the Mitchell River (and to a lesser extent, the Nicholson/ Tambo, contribute loads of nitrogen, phosphorus, and sediment to Lake King. Algal blooms are a current feature of the system.

MacLeod Morass is the only significant, public freshwater wetland in the system. The salinity and nutrient regimes of this system remain a knowledge gap.

Medium-term
Outcomes (2027)

A reduction in the number of years in which blue-green algal blooms occur in the lakes to less than five over the 20 years (2007–2027).

By 2027 water regimes in MacLeod Morass are managed to maintain freshwater conditions in the upper Morass as indicated by annual average EC of < 500 uS/cm.

Long-term
Outcomes (2027)

Extent and condition (density) of seagrass is maintained.

Macleod Morass is maintained as a freshwater wetland.

Theme - Water

Water – protecting and restoring waterways and riparian zones

Current State
(2021)

Domestic stock impacts on riparian corridors may be low compared to other locations in the State, but have been identified as a risk in some locations (e.g. Brodribb-Bemm Foothills, Genoa, Buchan and Lower Snowy). In addition, the Snowy River has over 90% of the natural flows extracted, resulting in impacts to river processes and biota.

Medium-term
Outcomes (2027)

Species control on priority rivers leading to reduced cover of willow across priority high value rivers.

Livestock grazing is on 75% of waterway frontages in cleared sections of priority reaches.

Extent, structure and diversity of vegetation on riparian corridors improved within cleared sections of selected priority reaches leading to improvements in in-stream habitat and bank stability.

Improved understanding of the risks to the condition of priority waterways. 

Long-term
Outcomes (2027)

The condition of riparian vegetation is improved in priority cleared waterways, providing habitat for native animals, and improving resistance and resilience, reducing risk of instability (Snowy River and rivers of the far east).

The condition of forested priority waterways and remote coastal wetlands is maintained.

Fish populations can move freely within the river systems of far East Gippsland critical times of year.

Theme - Water

Water – protecting and maintaining native fish populations

Current State
(2021)

Although the waterways of the local area are largely in good condition and barriers to connectivity are low, brown trout have been identified as a potential threat in some headwater streams and the effects of recent bushfires on water quality and habitat is of concern. The risk is highest in streams that support threatened galaxias species including McDowall’s galaxias, East Gippsland galaxias and Cann galaxias.

Medium-term
Outcomes (2027)

Suitable habitat is maintained in priority locations for small threatened native fish species by 2027.

Long-term
Outcomes (2027)

By 2040 populations of the following small native threatened fish species are stable: McDowall’s galaxias, East Gippsland galaxias and Cann galaxias.

Theme - Water

Water – protecting waterway health

Current State
(2021)

Waterways such as Forge Creek, Tom Creek and wetlands in this local area are subject to pressures from agricultural activities including stock grazing, nutrient and sediment inflows and past land clearing. 

Medium-term
Outcomes (2027)

Extent, structure, and diversity of vegetation on riparian corridors is improved along Forge and Tom creeks.

Extent, structure, and diversity of vegetation on Gippsland Plains priority wetlands is improved.

Long-term
Outcomes (2027)

The condition of riparian vegetation along Forge Creek, Tom Creek and priority wetlands is improved, providing habitat native animals, and improving resistance and resilience of waterways, reducing risk of instability.