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Geology Assessments 

Geological Assessments

Geodiversity is the equivalent of biodiversity but pertaining instead to non-living elements of the natural world encompassing the natural range of geological (bedrock), geomorphological (landform) and soil features, assemblages, systems and processes (Commonwealth of Australia 2002). Geodiversity significance is assessed based on a number of criteria including: 

  • Rarity

  • Scientific importance 

  • Aesthetic or landscape values 

  • Educational value 

  • Cultural value. 

Sites are assessed as significant at a particular scale of reference which may be local, regional, national, or international.

 

Kosciuszko National Park (KNP) management documents consider geodiversity conservation and management. The KNP Plan of Management identifies numerous significant geological and geomorphological features that occur within the park. This plan and the subsequent KNP Geodiversity Action Plan (KGAP) outline the actions required to ensure such features are protected, conserved, and promoted, and these documents were used as a starting point in the Geodiversity assessment.

 

This assessment was made in accordance with the Secretary’s Environmental Assessment Requirements (SEARs) for Snowy 2.0 Main Works. The assessments main objectives were to: 

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  • Describe the existing Palaeozoic/Cenozoic geodiversity values as identified in the  Kosciuszko National Park (KNP) Plan of Management, and the associated Kosciuszko National Park Geodiversity Action Plan (KGAP) study.

  • Identify and assess the potential for the presence of previously unrecognised Palaeozoic/Cenozoic geodiversity sites

  • Identify the sensitivities, risks, and opportunities associated with Palaeozoic/Cenozoic geodiversity in the context of the project

  • Recommend site-specific mitigation measures to reduce the impacts from the project on Palaeozoic/Cenozoic geodiversity sites wherever possible 

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The Cenozoic is the geological era extending from 66 million years ago (Ma) to the present. The geology of the Snowy 2.0 project area mainly comprises the Palaeozoic era (approximately 485 to 360 Ma) rocks deposited during the Ordovician to Devonian periods with mid-Cenozoic to younger cover deposits occurring in some areas.

 

The assessment is based on literature review, spatial data review, and observations made during a site visit to Palaeozoic/Cenozoic geodiversity features in the vicinity of Lobs Hole Ravine Road in northern KNP. The literature reviewed included recent geological and geotechnical reports undertaken for Snowy 2.0 in addition to the abundant past literature on the geology of the project area, and KNP management documents. Spatial data examined included newly-acquired aerial photos and LiDAR-derived DEM, in addition to existing geological mapping and other relevant data. The new remotely-sensed data was used, along with other available information including limited field data, to interpret the extent and context of Palaeozoic/Cenozoic geodiversity features within the project area.

kosciuszko-geodiversity-action-plan-01.j

Example of granite outcroppings, which can be found in the Kosciuszko National Park 

Predicted Impacts 

The Main Works project area includes some high-value Cenozoic geodiversity features which are included within a national heritage-listed national park. There are also peri-glacial block streams and tufa deposits which will undoubtedly be adversely impacted by construction with Snowy Hydro. 

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Two previously unidentified palaeozoic geodiversity sites were identified within the construction zone of the Tantangara Reservoir. 30 other palaeozoic sites that were not previously recognized were also identified, allowing the safe assumption that no other geodiversity sites are at risk with the project. 

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However new sites may be discovered in the Lobs Hole Road area, many of the newfound sites present the opportunity for learning and geotourism. 

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Snowy Hydro insists that with careful design, construction practices, and monitoring, impacts on geodiversity can be minimised and opportunities for education, research and public appreciation of geodiversity enhanced by the project. 

Mitigation

  • Minimise the road footprint through these sections as far as practicable;

  • Limit excavation into the block streams to the minimum required for road safety;

  • Avoid covering the upslope block streams with shotcrete or other materials that would permanently preclude viewing of the blocks;

  • Consider the visual impact of the road upgrade in the block stream sections and implement road design that will maintain landscape values.

  • Limit direct impacts on roadside tufa features where possible, in particular, those that display notable intact natural structures;

  • Maintain drainage in an as natural state as possible where the road crosses tufa-lined gullies;

  • Implement strict water and sediment controls during roadworks within the Lick Hole Gully and Cave Gully catchments upstream of the cliff-edge tufa deposits; and

  • Minimise vegetation clearing within the Lick Hole Gully and Cave Gully catchments upstream of the cliff-edge tufa deposits.

  • Regularly monitor for impacts during construction, and implement contingency measures in the event that unexpected impacts are identified; 

  • Facilitate the development of a safe stopping space and interpretive signage within the proposed road and disturbance footprint post-construction to enhance opportunities for geotourism viewing;

  • Facilitate the potential scientific study of the features post-construction including, if required, sharing of relevant project data.

  • Geodiversity awareness training for relevant personnel

  • Field checking for geodiversity at newly exposed construction

  • The requirement for reporting newly identified geodiversity sites
     

Critique

Snowy Hydro does a good job of thoroughly considering risks to geodiversity associated with the project. Mitigation options are also realistic and highly sensible. However, the unavoidable damage to 2 palaeozoic sites is problematic, this impact is, however, ameliorated by the increased awareness and carefulness towards geodiversity on the rest of the project work area. I just wish there was more detail on the exact impact on these geodiversity sites and options for decreasing said impact. 

Map of significant geological formations identified in the site area

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