We have successfully obtained a 2-year competitive disaster resilience grant with Commonwealth funding from the National Emergency Management Agency (NEMA) through the 2023 round of the Disaster Ready Fund (DRF). This grant totals $1.45M with a $701,500 contribution from the Federal Government, in addition to a $110,250 PhD stipend provided by the University of Tasmania. The funding further extends the work conducted Dr Ali Tolooiyan, Dr Ashley Dyson and Dr Gholamreza Kefayati on Tasmanian disaster resilience. The project seeks to further extend links between the UTAS School of Engineering and Tasmanian communities and government agencies through disaster resilience and sustainable engineering.
Project Overview
Site investigation techniques are vital in protecting residential developments in landslide-prone regions. Tasmanian policies and guidelines for suggested methods are not yet at the level used throughout the rest of the world, despite their regular use internationally. A modernised policy requires relevant site investigation techniques localised for a Tasmanian setting to mitigate landslide risk.
A rigorous set of non-destructive site investigation techniques will be conducted for Tasmania’s main problematic geological units. As a direct result, the project will produce recommendations to relevant local and state government authorities to provide individuals, communities and contractors with suggested approaches to reduce landslide disaster risk in urbanised development zones.
The project seeks to understand disaster risk through a comprehensive assessment to improve the quality and accessibility of information on ground conditions that impact critical urban development issues. It will increase access to relevant geotechnical and geologic data and information and landslide-prone communities and reduce disaster risk by establishing testing methods not readily used in Tasmania. These techniques (Multi-Channel Analysis of Seismic Waves – MASW and Cone Penetration Tests – CPT) are commonly implemented internationally and enhance capacity to identify and characterise sub-surface conditions that increase landslide hazard. Their implementation at key disaster-prone sites in the State will demonstrate their utility in Tasmanian landscapes and identify how they can be most effectively incorporated in regular site investigations. In doing this, the project will promote and establish guidelines for integrating these testing methods into site and regional assessments. Their regular use will bolster risk prevention in urban developments at elevated risk of damage by landslides by supporting improved planning and development choices.
Project Description
Tasmania’s urban environments can be affected by significant landslide hazards. As an example, houses and infrastructure in the West Tamar, Break O’Day, Launceston, George Town, Sorell, and Derwent Valley Local Government Areas (LGAs) have experienced major structural damage and even destruction by landslides. Numerous landslide-affected peri-urban sites illustrate the detrimental impacts of landslides on Tasmania’s built environment.
Tasmania’s geologic and climatic conditions directly control the moisture content of its soils. This is particularly important in many of the State’s lowland coastal areas, where the stability of poorly consolidated, fine-grained soils is strongly affected by groundwater. Wetting of those soils drives failure of soft clays that initiate as well as re-activate both shallow and deep-seated landslides. Initiation or acceleration of landslides is thus particularly likely during prolonged wet periods or even shorter-term storm conditions. For instance, creeping landslides in several parts of Tasmania accelerated during increased precipitation in recent La Niña years (2020-2022). The 2016 rainstorms that caused extensive flooding in northern Tasmania and sediment build-up in the Tamar estuary also triggered or reactivated many landslides. Early indications suggest that severe rainstorms in October 2022 similarly exacerbated landslide activity in lowland soils.
Slopes along several of Tasmania’s estuary systems are particularly susceptible to failure. In this environment, groundwater conditions influenced by river level, rainfall, landscape modification and anthropogenic inputs readily induce sliding in soft clay layers. Environmental change forecast for the remainder of this century – particularly increasingly frequent and energetic storms, and erosion due to sea-level rise – will further promote landslides in continually expanding coastal settlements, with considerable costs to local councils, private landowners, and possibly the State Government.
Damaging coastal landslides have been observed with increasing regularity in Southern Tasmania (e.g., Penna), Eastern Tasmania (e.g. Parnella), and the Tamar Valley, as urban development progresses. Coastal bluffs at all of these sites have experienced multiple failures in recent decades relating to water seepage and drainage issues that elevate groundwater pressures. Several of these landslides threaten houses.
The response to management of urban landslide risks in Tasmania differs within and between councils. This variability reflects differing experience and resourcing, inconsistency on what geotechnical data are required for evaluating and addressing landslide risk in new developments, and how landslide risk is managed in existing developments.
Critically, local Tasmanian councils lack sufficient funding to direct the use of the most effective site investigation methods, which are necessary to identify and understand risks from complex slope failures affecting residential developments. State funding has been limited for specific, localised site investigations. Additionally, state-level guidance for landslide investigations is less developed compared to other natural hazards (e.g. flooding). Importantly, the implementation in Tasmania of more appropriate landslide site investigation methods – which are commonly used elsewhere in Australia and other industrial countries – requires training, education, and awareness for both council staff and local geotechnical consultants.
Currently, Tasmania lacks a unified policy on-site investigations and specific testing methods for suitably assessing landslide risk to urban development zones. This project seeks to 1) address the need for appropriate site investigation tools and 2) provide guidance on how local councils can effectively integrate optimal to improve development decisions and landslide risk management.
This two-year project will comprise site investigations of three landslide-affected urbanised areas; analysis and computational modelling of results; development of training materials to guide local practitioners based on the appropriate use of engineering assessment methods for site investigations; and development of guidelines to support local councils in requesting improved reporting to guide Tasmanian urban development decisions.
The last contribution is a critical component and essential to ensuring that urban development is conducted in a way that minimises landslide risk. Specifically, a series of recommendations will be provided, enabling local councils and relevant State government agencies to adopt more suitable site investigation techniques for reducing landslide disaster risk in Tasmania.
The work program will deliver cost-effective approaches to understand and manage ongoing and future landslide risk. This includes supporting improved local and State government policies for housing and infrastructure development within Tasmanian’s urban zones and geologically comparable regions.
In collaboration with Mineral Resources Tasmania, UTAS School of Engineering’s Dr. Ali Tolooiyan and Dr. Ashley Dyson as part of the Computational Engineering for Sustainability Lab (CES-Lab) have a strong history of successfully delivering landslide and slope stability risk mitigation projects in Tasmania and Victoria, having recently completed the National Disaster Risk Reduction Grants Program (NDRRGP) funded Kunanyi (Mt Wellington) Debris Flow Risk Reduction and Mitigation Strategies project, Drs Tolooiyan and Dyson developed strategies for mitigating landslide risks for the City of Hobart through protective barrier assessment.
Further information about our work on natural hazards can be found on our Natural Hazards page.