Peter Dahlhaus

Salinity on the southeastern Dundas Tableland, Victoria

Historical evidence of early salinity, vegetation and landuse changes, and pedological studies have been used in formulating a new model for salinity processes acting on the Dundas Tableland in southwestern Victoria. Contrary to previous assumptions, salinity in this area was a feature of the pre‐European landscape and was noted in the earliest surveys and journals. Analysis of historical records show an initial post‐settlement increase in the tree numbers, followed by a rapid decline much later than previously assumed. Accumulation of salts in the regolith may be attributed to marine incursions during the Miocene and Pliocene, the extensive weathering to develop a deep regolith, and wind‐blown and cyclic salt accumulation. A trend analysis of historical streamflow and bore hydrograph records does not indicate rising groundwater levels. The pedological features of duplex and sodic soil profiles support a history of prolonged seasonal waterlogging. A model with seasonal lateral flow of water through the upper regolith can better account for the spread of salinity than the rising groundwater hypothesis. By control of waterlogging, land managers could improve soil structure, enhance root growth and soil water use, as well as inhibit the spread of salinity.

A New Assessment Framework for Transience in Hydrogeological Systems

The importance of transience in the management of hydrogeologic systems is often uncertain. We propose a clear framework for determining the likely importance of transient behavior in groundwater systems in a management context. The framework incorporates information about aquifer hydraulics, hydrological drivers, and time scale of management. It is widely recognized that aquifers respond on different timescales to hydrological change and that hydrological drivers themselves, such as climate, are not stationary in time. We propose that in order to assess whether transient behavior is likely to be of practical importance, three factors need to be examined simultaneously: (1) aquifer response time, which can be expressed in terms of the response to a step hydrological change (τstep ) or periodic change (τcycle ); (2) temporal variation of the dominant hydrological drivers, such as dominant climatic systems in a region; (3) the management timescale and spatial scale of interest. Graphical tools have been developed to examine these factors in conjunction, and assess how important transient behavior is likely to be in response to particular hydrological drivers, and thus which drivers are most likely to induce transience in a specified management timeframe. The method is demonstrated using two case studies; a local system that responds rapidly and is managed on yearly to decadal timeframes and a regional system that exhibits highly delayed responses and was until recently being assessed as a high level nuclear waste repository site. Any practical groundwater resource problem can easily be examined using the proposed framework.

Rockfalls: predicting high‐risk behaviour from beliefs

Purpose – The purpose of this paper is to gain an understanding of the publics beliefs, attitudes and knowledge regarding rockfalls, and to see whether these variables could predict whether a person is likely to enter high‐risk rockfall areas.Design/methodology/approach – A questionnaire was developed to measure beliefs (informed by the health belief model), knowledge, and previous behaviour in relation to rockfalls. Questions were also included to measure attitudes regarding rockfall caution signs. In total, 138 members of the general public completed the questionnaire.Findings – High‐risk behaviour was more likely if the person was male and if the person had the belief that sign‐posted high‐risk areas were not dangerous. Further, believing that the sign‐posted areas were not dangerous was more likely among people who held negative attitudes towards cautionary signs; specifically, these participants were more likely to doubt the validity of the warning signs.Research limitations/implications – The resea...

Interpretation and misinterpretation of warning signage: Perceptions of rockfalls in a naturalistic setting

The aim of the present study was to investigate the factors relating to non-adherence to warning signs about falling rocks from coastal cliff faces. Face-to-face interviews (n = 62) in a naturalistic setting (in the vicinity of a high-risk rockfall area) were conducted to investigate attention to and comprehension of warning signs, as well as beliefs relating to non-adherence of the signage. It was found that, while most participants could correctly identify the danger in the area and had noticed the warning signage, less than half of the participants could correctly interpret the signage. The perception of danger did not differ significantly between the participants who had, or had not, entered the high-risk zone. Differences in knowledge and beliefs between local residents and visitors to the area were identified. It was concluded that the warning signs did not provide enough detail for people to make informed decisions about safe behaviours. Comprehension of the signage may have been hampered by a lack of prior-knowledge of the particular risk, a failure to think carefully about the situation (i.e. low-effort processing), and the pictorial representation on the signs misleading the participants as to the true danger.

SLOPE STABILITY AND ROCKFALL HAZARD ANALYSIS IN OPEN PIT ZINC MINE

Rockfalls are a major safety hazard in open cut mines, particularly in large-scale deep pits. The geotechnical design relies on in-situ, site-specific, rock slope data to predict the trajectories and velocities of rockfalls that present a residual hazard in the mines. This paper presents slope stability analyses using both static general limit equilibrium methods and finite element stress analyses to estimate unstable areas and slope displacements in the mid-west slope at Glencore Zinc’s Handlebar Hill Open Cut mine at Mt. Isa, Queensland, Australia. A conventional program -RocFall- was used for the slope rockfall risk assessment. Results indicate the possible slope benches involved in the initiation of rockfalls, and the maximum run-out distance, which could be defined as the pits hazardous zone. A rockfall restraining system to absorb the impact energy of boulders and prevent them further falling was also modelled.

Liberating soil data for profitable agriculture and catchment health in the Corangamite region, Australia

ABSTRACT Detailed soil data has been collected in the Corangamite region of south-east Australia for over 80 years, as a testament to the productive value of the region’s agricultural soils. Soil science over that period has resulted in soil maps, soil investigation sites and archival materials that provide valuable baseline data for the analysis of trends over time. This legacy data has been brought together with contemporary data in the award-winning Soil Health Knowledge Base, an Internet portal based on spatial data infrastructure that interoperably federates data (open data, research data, industry data, sensor data, legacy data, crowdsourced data … any available data). The portal provides the best available data sources for research and consulting, as well as functions for both the private reward and the public good. The ultimate intent is to provide timely decision support for agricultural enterprises and catchment managers to protect, enhance and restore soil health.

Enabling global exchange of groundwater data: GroundWaterML2 (GWML2)

GWML2 is an international standard for the online exchange of groundwater data that addresses the problem of data heterogeneity. This problem makes groundwater data hard to find and use because the data are diversely structured and fragmented into numerous data silos. Overcoming data heterogeneity requires a common data format; however, until the development of GWML2, an appropriate international standard has been lacking. GWML2 represents key hydrogeological entities such as aquifers and water wells, as well as related measurements and groundwater flows. It is developed and tested by an international consortium of groundwater data providers from North America, Europe, and Australasia, and facilitates many forms of data exchange, information representation, and the development of online web portals and tools.RésuméGWML2 est une norme internationale pour l’échange en ligne de données sur les eaux souterraines qui aborde le problème de l’hétérogénéité des données. Ce problème rend les données sur les eaux souterraines difficiles à découvrir et à utiliser parce qu’elles sont structurées et fragmentées en de nombreux silos. Surmonter l’hétérogénéité des données requiert un format de données commun; cependant, jusqu’au développement de GWML2, une norme internationale appropriée faisait défaut. GWML2 représente les principales entités hydrogéologiques telles que les aquifères et les puits d’eau, ainsi que les mesures connexes et les écoulements d’eau souterraine. La norme fut développée et testée par un consortium international de fournisseurs de données sur les eaux souterraines en provenance d’Amérique du Nord, d’Europe et d’Australasie; elle facilite de nombreuses formes d’échange de données, la représentation de l’information et le développement de portails web et d’outils en ligne.ResumenGWML2 es un estándar internacional para el intercambio en línea de datos de aguas subterráneas que aborda el problema de la heterogeneidad de los datos. Este problema hace que los datos de agua subterránea sean difíciles de encontrar y usar porque están estructurados en diversas formas y fragmentados en numerosos depósitos de datos. La superación de la heterogeneidad requiere un formato de datos común; sin embargo, hasta el desarrollo de GWML2, faltó un estándar internacional apropiado. GWML2 representa entidades hidrogeológicas claves, como acuíferos y pozos de agua, así como mediciones relacionadas y flujos de aguas subterráneas. Es desarrollado y probado por un consorcio internacional de proveedores de datos de agua subterránea de América del Norte, Europa y Australasia, y facilita muchas formas de intercambio de datos, representación de información y desarrollo de portales y herramientas web en línea.摘要地下水ML2是地下水数据在线交流的国际标准,重点针对数据异质性问题。这个问题使地下水数据很难找到和利用,因为数据结构各异,呈碎片状储存在众多的数据库。克服数据异质性需要常见的数据格式;然而,地下水ML2开发之前,一直缺乏一个适当的国际标准。地下水ML2展示了关键的水文地质实体诸如含水层和水井以及相关的测量结果和地下水流。经过来自北美、欧洲和澳洲的地下水数据提供者的国际联盟的开发和测试,促进了多种形式的数据交流、信息展示,以及在线网络门户网站和工具的开发。ResumoGWML2 é um padrão internacional para troca online de dados de águas subterrâneas que trata do problema da heterogeneidade dos dados. Este problema torna os dados de águas subterrâneas difíceis de serem encontrados e usados, por serem estruturalmente diversos e fragmentados em numerosos locais de armazenamento. Superar a heterogeneidade de dados requer um formato comum de dados; entretanto, até o desenvolvimento do GWML2, não havia um padrão internacional apropriado. GWML2 representa entidades-chaves hidrogeológicas tais como aquíferos e poços de captação, assim como medições relacionadas e fluxos hidrogeológicos. Foi desenvolvida e testada por um consórcio internacional de provedores de dados de águas subterrâneas da América do Norte, Europa e Austrália, facilitando várias formas de trocas de dados, representação de informação e desenvolvimento de portais online e ferramentas.

Finite Element Analysis of Rock Slope Stability Using Shear Strength Reduction Method

Finite element analysis incorporating the shear strength reduction method was applied to study the west slope stability of an open cut mine in Australia using Mohr–Coulomb and generalized Hoek–Brown criteria. The pit of the mine had multiphase excavations and reached 180 m in depth. The study investigated three slope configurations, namely, Stage 1 inter ramp slope 43°, Stage 2 inter ramp slope 49° and optimized Stage 2 slope 54°. When implementing the generalized Hoek–Brown failure criterion, the equivalent factor of safety was 1.96, 1.87 and 1.40 under dry slope for the three configurations, respectively. However, under partly saturated conditions, the optimised slope would have a factor of safety 1.16. Furthermore, the generalised Hoek–Brown criterion generated lower factors of safety than the Mohr–Coulomb failure criterion. The difference is related to an overestimation of the shear strength parameters by the linear Mohr–Coulomb criterion under low confining stresses compared with the non-linear Hoek–Brown.

KINEMATIC ASSESSMENT OF SLOPES AT HANDLEBAR HILL OPEN CUT MINE, MT. ISA, QUEENSLAND, AUSTRALIA

A complete kinematic analysis was conducted for the west slope at the Handlebar Hill mine using the Rocscience/Dips 6.0 software. The west slope was divided into three zones: W1 (south-west), W2 (mid-west) and W3 (north-west), which were then subdivided into nine small elements to increase the certainty of parameters. This enabled the analysis to define the potential kinematics of motions of critical structures. Small scale joints, bedding, faults, shears along the discontinuities were plotted and the data were analysed systematically. The results indicated that the potential toppling mode created by discontinuities can lead to direct/flexural toppling failure. The kinematic feasibility also revealed that the intersections of the discontinuities within the critical zone can structurally control the wedge planar failure modes. The results will assist the mine geotechnical engineers to understand the potential slope failure mechanisms and their locations.