Update of EMR feature – MacPhee, Elizabeth and Gabriel Wilks (2013) Rehabilitation of former Snowy Scheme Sites in Kosciuszko National Park. Ecological Management & Restoration, 14:3, 159-171. Doi https://onlinelibrary.wiley.com/doi/10.1111/emr.12067
Key words. Habitat construction, steep slopes, rock spoil.
Introduction. Our original EMR feature article described the origins of this large, long-term rehabilitation program and the challenges faced in the first 10 years. The program’s aim was to address a range of impacts upon montane and sub-alpine vegetation and river corridors in Kosciuszko National Park from the Snowy Hydro Scheme, constructed from 1949 to 1974. Impacts included dumping of large volumes of rock spoil, loss of topsoil and native vegetation, introduction and spread of weeds and asbestos fragments in the landscape. The article outlined the development of methodologies for restoration, particularly planting trials on steep rock spoils, and how obstacles such as slope instability, plant material availability and lack of soil were being overcome. The process of program implementation was given, including environmental and cultural heritage assessments undertaken as part of site works. In 2013 a number of positive outcomes were already evident at the 200 sites that had been subjected to at least some treatment, including 18 sites where major rehabilitation works were undertaken. Outcomes included reduction in waterway impacts and invasive weeds, expansion of the Kosciuszko fauna database, regional community benefits, and production of an Australian Alps Rehabilitation Field Guide.
Further work. The Former Snowy Scheme Rehabilitation Program continues to reduce the long term environmental and safety risks of old degraded construction sites to Kosciuszko National Park, as well as improve their visual and ecological function. Some sites treated by 2013 have blended in with the surrounding landscape and are difficult to identify. Many sites are continuing to improve in condition over time, with distinct vegetation layers, natural plant recruitment and evidence of native fauna habitat. Construction history, rock spoil and loss of soil and plant species remain evident at highly altered sites, despite a high standard of rehabilitation work.
An additional 12 Major rehabilitation works have been undertaken since 2013, with selected signature projects and rehabilitation techniques described below. Note that the former Snowy Scheme rehabilitation program does not address the impact of current Snowy Hydro Limited or proposed infrastructure and support networks such as powerlines, easements, river regulation or roads.
1. Rehabilitation of the Tooma–Tumut Access Tunnel Adit Spoil Dump. This spoil dump (Fig. 1) is located on the highly incised upper reaches of the Tumut River. The spoil originates from construction in 1958-1961 of the Eucumbene–Tumut Tunnel, which transfers the headwaters of the Tooma River to Tumut Pond. Following earthworks in 2017, the planting crew successfully planted, watered, fertilised and mulched approximately 12,000 plants on rock spoil, with monitoring being undertaken by Greening Australia Capital Region staff (Fig 2.)
2. Construction of contained habitat for the Southern Corroboree Frog. A series of remote enclosures (Fig 3) have been constructed in both rehabilitation areas and former habitat locations to enable re-introduction of this Critically Endangered species (Fig 4), following the devastating impacts of chytrid disease. These enclosures are developing essential stepping stones for frogs from captive breeding programs to move back into the wild. Design of enclosures requires ensuring self-sustaining food and water, shallow ponds for breeding, ability for Threatened Species staff to monitor and control disease and exclusion of other frogs. These works have been done in partnership with NSW Threatened Species staff and zoo institutions.
3. First live record of Smoky Mouse in Kosciuszko National Park. The Smoky Mouse (Pseudomys fumeus Fig. 5) was found alive and well for the first time in Kosciuszko National Park, at a Happy Jacks rehabilitation site. Up until the discovery, the only currently known population of the small, smoky grey coloured mouse still surviving in NSW was in the Nullica area, NSW South Coast. Three individuals, 2 males and 1 female were a significant find for survival and database records of this Critically Endangered Species, and a technical short note was published in EMR in 2017 by fauna surveyor Martin Schulz who found the animals.
4. Making people and places safer with rehabilitation. Sites that housed construction depots and townships during Snowy scheme construction still contained fragments of asbestos which were rapidly degrading due to weather exposure. As total removal was not feasible, the rehabilitation team worked with asbestos experts to develop practical measures to reduce public safety risks. At the remote Junction Shaft Contractors Camp (at Happy Jacks, Figs 6 and 7) and a former township and current camping ground at Island Bend a range of techniques were developed, delineation of zones for suitable uses, creating natural vegetation buffers and capping with rock spoil and plants.
5. Applying techniques beyond Kosci. Project team members took some winter time out of Kosciuszko to ‘grow’ a protection zone for a known population of Endangered Green and Golden Bell Frog (Litoria aurea) and constructed a series of ponds for future breeding in an old sand quarry at Worrigee Nature Reserve, Nowra (Fig 8). Given former quarries are a feature of a large infrastructure project such as the Snowy Scheme, the team had the technical knowledge for how to restore ecological function despite a radical departure from usual flora and fauna species. A range of techniques including neighborhood consultation, barrier logs and blocks, berms and vegetation were used to reduce the impact of recreational and unauthorised motorbikes and rubbish dumping.
6. Growing rehabilitation resources and protecting karst ecosystems. The use of treated waste at the Yarrangobilly Caves visitor precinct to grow snow grasses (Poa spp.) for use in rehabilitation projects across Kosciuszko and been continued and developed (Fig. 9). A renewed emphasis on site production has enabled Poa seed to be available for other projects within the Park. This provides an ecologically preferable option for soil stabilisation and ground cover establishment, reducing the risk of weed invasion and dependence on sterile rye corn as the only available option.
Lessons Learned. It is clear that this is a unique rehabilitation project due to the large number of sites, the natural and heritage values of Kosciuszko National Park and the longevity and continuity of the commitment (approx. 20 years). Understandably, however, at this point in time challenges in rehabilitation remain. ‘Off the shelf’ rehabilitation products are limited due to remoteness of locations, plant species required, Park management policies and required hygiene protocols. It is important that additional threats are not accidentally introduced, such as foreign pathogens and flora and fauna. As much as possible, resources such as coarse woody debris, woodchip, plant material and compost are sourced from within the Park. A flexible and dynamic approach to the very definition of rehabilitation and techniques and materials is required. Specific lessons include the following.
Adding organic material on degraded sites is always beneficial. Rehabilitation success has been most obvious where logs, litter, woodchip and straw have been added to the site, to provide mico-niche climate, habitat, and improve soil. While this may increase short term management requirements such as weed control, the commitment is worth it due to the improved results.
Creating compost from old sawmill sawdust has worked well for this rehabilitation project. The most recent development however is in the use of organics waste and treated effluent from visitation facilities as a compost, and there is opportunity for this on-Park recycling to develop.
Other resources such as rice straw have become limited during periods of sustained drought and less rice production. This will remain a challenge into the future. The value of minimising ground cover loss, retaining natural soil characteristics and organic matter in situ and ensuring rapid rehabilitation after disturbance in future developments will become increasingly important for rehabilitation success.
Be creative with team skills and capacity. Problems such asbestos contaminant presence must be addressed for safety, but doesn’t mean walking away from the challenge. A degraded site may be the perfect place to develop species targeted habitat. Seek expertise advice and consider a range of current and new solutions.
Contact. Gabriel Wilks, Senior Project Officer, NPWS Southern Ranges Services. PO Box 472, Tumut NSW 2720. Email: Gabriel.Wilks@environment.nsw.gov.au