Environmental Aspects of the Anthony–Pieman Hydropower Scheme

Environmental aspects of the Anthony–Pieman hydropower scheme Pieman Sustainability Review June 2015 FACT SHEET Background The Anthony–Pieman hydropower scheme provides a highly valued and reliable source of electricity. The total water storage is 512 gigalitres and the average annual generation is 2367 gigawatt hours. Construction of the Anthony– Pieman hydropower scheme has resulted in creation of water storages (lakes) and alterations to the natural flow of existing rivers and streams. The Pieman Sustainability Review is a review of operational, social and environmental aspects of Anthony–Pieman hydropower scheme influenced by Hydro Tasmania. This fact sheet elaborates on environmental and river health information presented in the summary report of the Pieman Sustainability Review, available at http://www.hydro.com.au/pieman-sustainability-review Ecology of the Anthony-Pieman peppermint (Eucalyptus coccifera) forest and woodland hydropower scheme and alpine heathlands. Threatened species Vegetation The West bioregion has a low diversity of flora and fauna The Anthony–Pieman hydropower scheme mostly falls compared to other bioregions in Tasmania. However, within the Tasmanian West bioregion which includes the the natural habitats of the West bioregion are generally west and south-west of Tasmania but excludes the north- intact and it is the Tasmanian bioregion least impacted by west. The Tasmanian West bioregion is characterised by human activities. Therefore there are few threats to flora high rainfall and wet vegetation types, predominantly and fauna in the Anthony–Pieman hydropower scheme. rainforest, wet eucalypt forests, buttongrass moorland and wet scrub. The upper eastern parts of the Anthony– There are 23 threatened species (two mammals, four Pieman hydropower scheme fall within the Tasmanian birds, one reptile, one fish, nine invertebrates and six plant Central Highlands bioregion. species) recorded from the Anthony–Pieman hydropower scheme, particularly the middle and lower areas The rainforests of western Tasmania are dominated where Hydro Tasmania water storages and associated by myrtle beech (Nothofagus cunninghamii). hydropower infrastructure are located. Fourteen Sassafras (Atherosperma moschatum) and celery top threatened plants and two threatened animal species (Phyllocladus aspleniifolius) are also common. At lower have been recorded in sub-alpine and alpine habitats in elevations in the Anthony–Pieman hydropower scheme the upper parts of the Anthony–Pieman hydropower stringybark (Eucalyptus obliqua) is the dominant wet scheme above the Hydro Tasmania hydro generation forest eucalypt, replaced by gum-topped stringybark infrastructure. These species are not particularly affected (Eucalyptus delegatensis) at higher elevations. Near the by hydropower operations. They generally occupy coast, non-forest vegetation communities dominate, restricted habitats that are sensitive to disturbance. particularly buttongrass moorland and western wet scrub communities. At higher elevations, including the Two threatened species that are directly affected by headwaters of the Henty and Pieman rivers, sub-alpine Hydro Tasmania operations are the azure kingfisher and alpine vegetation occur, including alpine yellow gum (Ceyx azureus subsp. diemenensis) and Australian (Eucalyptus subcrenulata) forest and woodland, snow grayling (Prototroctes maraena) which are both known to occur in the Henty River and the Pieman River downstream of Reece Dam. The azure kingfisher is listed FACT SHEET as endangered in the Tasmanian Threatened Species Protection Act 1995 (TSP Act) and the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). It is a small (14 cm long) brilliant azure blue bird with an orange breast that nests in burrows dug into the bank of a river or creek. The azure kingfisher dives into streams to catch small fish. The Threatened Species Listing Statement1 for the azure kingfisher identifies a potential threat to the species from fluctuating water levels in controlled rivers that may flood nest tunnels excavated low in the banks of rivers. The Figure 1: Australian Grayling juveniles (80 mm approx.) captured during flooding of sections of rivers upstream of dams is also December 2013 capture/translocation period. Photo taken by Rob likely to have removed potential breeding and foraging Freeman (IFS) habitat for the species. The Australian grayling is listed as vulnerable in the TSP magnitude of flow releases can potentially affect Act and the EPBC Act. It is a diadromous fish species physical and ecological processes such as: (has life stages in both fresh and marine waters) that • influencing the composition of aquatic and riparian grows to 300 mm and has a distinctive cucumber communities smell. Adult fish live in freshwater where they lay their • alteration of river bed and channel morphology eggs in gravel on the bottom of rivers. On hatching, with prolonged low-velocity flows causing siltation the larvae are swept downstream into coastal waters and smothering of habitat, and prolonged high- where they remain as juveniles for about six months velocity flows causing scouring and erosion before returning to fresh water. The major threat to this • potential impacts on the reproductive success species is the construction of barriers that prevent adults of Australian grayling through changed flow migrating upstream and larvae moving downstream. regimes during the spawning season and physical Australian graylings have been recorded in the Pieman alteration to spawning habitat. River downstream of Reece Dam and in the Henty River downstream of the Anthony–Pieman hydropower • Dams are a barrier to fish passage and thus affect scheme. In December 2013, in a pilot study to assess the the sustainability of populations of migratory fish. feasibility of implementing a fish relocation program at There are populations of Australian grayling and the Reece Dam, 20 grayling were caught and translocated spotted galaxiid (Galaxias truttaceus) in the Pieman to locations upstream from Reece Dam (Figure 1). This River below Reece Dam and in the Henty River that was the first time Australian graylings had occurred in the cannot access upstream breeding habitats due to the Pieman River since the Reece Dam was constructed. presence of a dam. The impact of Hydro Tasmania operations on populations of other aquatic fauna and Hydro Tasmania carefully manages potential impacts flora species and their habitats is not well understood. on threatened species from maintenance and upgrade • Canals, pipelines and penstocks provide links between works. Any works require an Environmental Impact waterways that did not exist previously and thus Assessment as part of the project planning process. provide a mechanism for the transfer of aquatic Any potential impacts on threatened species are pests and pathogens, pest weeds, introduced fish, addressed by an Environmental Management Plan to and native fish to areas where they did not originally eliminate, or at least, minimise risks. occur. Although there are no incidences of the Environmental issues transfer of aquatic pests within the Anthony–Pieman hydropower scheme, the enhanced connections of There are few significant environmental issues within waterways through hydropower infrastructure can the Anthony–Pieman hydropower scheme because the facilitate the spread of pests and pathogens. For natural environment is largely intact. However there are example, there have been sub-catchment transfers of environmental issues associated with Hydro Tasmania redfin ( ) and Canadian pondweed water storages and management of rivers, including: Perca fluviatilis (Elodea canadensis) in the upper River Derwent, via • Flow modification downstream of dams, particularly flow diversion infrastructure. The transfer of these in the Pieman and Henty Rivers. The timing and pests and native fish can pose a threat to endemic species. 1 Threatened Species Section (2012). Listing Statement for Ceyx azureus subsp. diemenensis (azure kingfisher). Department of Primary Industries, Parks, Water and Environment, Tasmania. Pieman Sustainability Review Environmental aspects of the Anthony–Pieman hydropower scheme 2 Pests and weeds FACT SHEET Phytophthora and Melaleuca (paper barks and honey-myrtles). To date myrtle rust has not been identified in areas Root-rot, or dieback fungus (Phytophthora cinnamomi) is an introduced water mould that can cause plant disease where Hydro Tasmania operates in the Anthony–Pieman hydropower scheme. and death in native Tasmanian vegetation. It poses a serious threat to susceptible plant species found in open Weeds vegetation in lowland environments (below 700 m) such There are widespread infestations of both pink pampas as moorlands, heathlands and dry eucalypt forests where grass (Cortaderia jubata) and toetoe pampas grass rainfall is greater than 600 mm. Phytophthora has the (Austroderia richardii) around Rosebery and along the potential to significantly impact the ecology of susceptible Murchison Highway south of Tullah. Other invasive weeds native vegetation communities and threatened plant species. There are confirmed records of Phytophthora that are widespread in the Anthony–Pieman hydropower scattered throughout the Anthony–Pieman hydropower scheme are blackberry (Rubus fruticosus agg.), Canary scheme, with more frequent records from along the broom (Genista monspessulana), English broom (Cytisus Pieman River, near Savage River and around Lake Pieman scoparius) and gorse

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