Melbourne School of Engineering Department of Civil & Environmental Engineering

Special Presentation: 'Enhanced stream flow forecasting by coupling satellite observations, in situ data and catchment models using data assimilation methods'

The aim of research undertaken in eWater CRC Project D1 is to develop and facilitate improved prediction and forecasting by stream flow models through better integration of observations in hydrologic models. Better forecasting skill by catchment models will enable better management decisions by river managers and planners. A key element in this project is to improve catchment-scale hydrologic models through utilization of multiple types of high frequency spatial data including: (1) reflective, thermal and microwave remote sensing; (2) ground-based radar-rainfall; and (3) 7-day forecasts from Numerical Weather Prediction models. Outputs from this work will deliver into two eWater CRC Product Development Programs, being: (1) River OPerationS (RiverOPS); and (2) Water and Constituent Accounting Simulation Tool (WaterCAST). There are multiple benefits for developing an improved capability for stream flow forecasting. These include improved efficiencies of water use through better anticipation of river inflows (particularly associated with flows from unregulated tributaries); a concomitant reduction in losses and shortfalls; better targeting of environmental flows by augmenting natural flow events; basin wide consistency in management operations based on a thorough knowledge of variation in inflows and offtakes  in time and space; and, an enhanced capability for predicting and monitoring flood events. However, current infrastructure and methodologies are not sufficiently technologically mature to support an operational system at this time. Furthermore, institutional and technological barriers exist which maintain the status quo in river operations. To realize the benefits of improved flow forecasting, directed investment into specific research and development areas is needed, including: (1) Improved synthesis of rainfall data from satellite, ground and numerical weather models; (2) Development of improved spatially distributed rainfall-runoff models with internal flow routing schemes that provide prognostic estimates of flow at catchment exit points; (3) Acquisition and processing of relevant satellite data products in near real time from operational and research satellites across a range of wavebands; (4) Computationally efficient numerical algorithms for minimizing differences between observed and model state variables that account for different types of data and their error characteristics; and (5) Establishment of implementation pathways for adoption and use of flow forecast products by river management agencies and in policy development. In this presentation, the key elements of the developing forecasting system will be shown

Special Presentation: 'State-of-the-art techniques for modelling structures subjected to extreme loadings - A review'

Recently,structures across the globe have become more vulnerable to the threat of terrorism, accidental explosions, the proliferation of weapons, tsunami, hurricane, etc.  Consequently, a number of concerns have been raised on the performance of structures under extreme loads. This presentation will give an overview of the latest technologies in modelling structures subjected to extreme loadings. Some case studies will be discussed including the World Trade Centre collapse investigation and Pentagon aircraft impact modelling. Some examples of the advanced modelling developed at the University of Melbourne will also be presented.  

Phd Confirmation Seminar:"Predicting nitrogen losses from dairy farming systems at multiple spatial scales"

In the intensive agricultural regions of Australia, as in many parts of the world, the loss of nitrogen (N) at scales from farms to catchments is a concern.  Measures to abate this problem continue to be limited by a lack of understanding of the aspects of farming systems that contribute to the release excess nutrients.  Additionally the link between landscape characteristics and hydrological processes that control nitrogen loss at the catchment scale have not been well investigated.  A range of models has been developed to describe N generation and movement at different scales, although only a few attempts have been made to link these scales.  Point scale N-generation models will be used at the farm level to model fluxes of N and water from dairy farming systems.  A distributed catchment modelling framework that combines models operating at different scales will be used to estimate N losses in a catchment used for dairy farming.   This framework will incorporate systems modelling and will be calibrated and tested at a range of spatial scales.  The model will be calibrated using stream chemical data from a nested catchment monitoring program.  Utilising a combination of water monitoring and isotope chemistry, water and N fluxes from various spatial units in the landscape will be investigated.  Through this research advances will be made in the understanding of N links between farms and catchments.

PhD Presentation: 'Using environmental tracers in hydrological studies'

Naturally occurring environmental tracers are a commonly applied and powerful tool in hydrological and hydrogeological studies.  They can be applied in a purely qualitative manner, to improve understanding of a hydrological system, and also to quantify water and salt balances.  There are a variety of types and ways in which tracers can be applied in a hydrological context. This presentation provides an overview of basic concepts, data collection procedures and useful interpretation techniques, with focus on use in semi-arid / arid systems.

PhD Presentation: 'Development and application of a hydrological index to characterise threat to river health'

One measure of the ecological health of a river can be obtained by characterising the differences in flow regime between natural and current conditions. A measure of ecological health of a specific river reach can be developed by identifying the flow components most important to the biota of interest; however, when applied to a whole river system, or even region, there is the added complexity of identifying a wider range of flow components for regimes of different natural variability. This paper describes the development and application of a hydrological index that can be used to characterise the difference in flow components under natural and current conditions, in a manner that takes into account natural differences in flow variability. The measure has the dual purpose of firstly capturing the degree of departure of current conditions from the natural flow regime, and secondly, providing a means of directly comparing the river health of catchments with flow regimes of differing variability. One of the difficulties in developing a single hydrological index of river health is that there are a number of flow components of interest, and moreover these flow components may be highly correlated. Thus, the information contained in one flow component may explain the variation in another component deemed to be of importance. To ensure that this correlation does not bias the overall measure of ecological health, the paper also presents a means for objectively combining and weighting the different measures in order to facilitate the comparative analysis across different systems.

Special Presentation: Uniwater - a major joint water research initiative between University of Melbourne and Monash University

The two leading Australian universities have joined forces in Uniwater – each putting in more than $1 million over three years - to spearhead a unique collaboration which creates a powerful critical mass of expertise in water-related research. Uniwater has four strategic objectives –

• Maximising environmental return on investment in repair of rivers, groundwater and catchments.
• Realising the potential of irrigated and dryland agriculture using less water.
• Providing a reliable and sustainable water supply to Australia’s growing cities, and
• Developing water policies and institutions within a Federation framework.

Special Presentation: 'Detection and attribution of climate change effects on tropical cyclones'

In climate change science, detection is the "process of demonstrating that climate has changed in some defined statistical sense, without providing a reason for that change". This could involve anything from a simple statistical analysis of a trend of a chosen observed variable to a complex fingerprint analysis of a combination of variables. In contrast, attribution implies not only that a signal has been detected but that it is of the correct magnitude expected from projections of climate change due to anthropogenic forcing. This talk summarizes the most recent predictions of the effect of climate change on tropical cyclones, and examines whether there have been any impacts on tropical cyclone behaviour to date.

Special Presentation: 'Numerical particle-scale study of swelling pressure in clays'
  
Given a montmorillonitic clay soil at high porosity and saturated by monovalent counterions, we investigate the particle level responses of the clay to different external loadings. As analytical solutions are not possible for realistic arrangements of particles, we employ a rather sophisticated micromechanical models (based on solution of the Poisson-Nernst-Planck equations) by means of finite element methods, thereby estimating counterion and electrical potential distributions for particles at various angles and distances from one another. We then calculate the disjoining pressures using the van’t Hoff relation and Maxwell stress tensor. As the distance between the clay particles decreases and double-layers overlap, the concentration of counterions in the micropores between clay particles increases. This increase lowers the activity of the porefluid and creates an activity gradient that, creating the so-called “disjoining” or “osmotic” pressure. Because of this disjoining pressure, it is clear that particles need not contact one another in order to carry and “effective stress”. As far as we are aware, we show for the first time the potential energy stored in various particle arrangements. This work may lead towards theoretical predictions of the macroscopic load deformation response of montmorillonitic soils based on micromechanical modeling of particles.

PhD Presentation: 'Supercritical water gasification of sewage sludge'

Supercritical water gasification (SCWG) is a novel conversion process especially for wet feedstock to fuel gas production. The objective of this thesis is to characterise SCWG of sewage sludge (SS) by theoretical and experimental studies. Computer models were developed to investigate the stoichiometry, thermodynamics and kinetics of the process. The stoichiometric model was developed based on an SS ideal reforming reaction for estimating maximum achievable hydrogen production while a non-stoichiometric formulation was applied for developing the equilibrium model for the SCWG thermodynamics. These models revealed that SS was found to be the best-suited feedstock for hydrogen production, comparing to other prospective biomasses investigated. It was found that temperature, pressure and feed characteristics influence the hydrogen yield in the product gas and high-temperature and low-pressure SCWG operation with high water content in the feed was found to favor it. The kinetic model has been developed by using a verified numerical optimisation code based on the Complex method. The data used was deduced from experiments which were conducted in micro-quartz batch reactors. The experimental results also showed that hydrogen production was significantly enhanced by increasing temperature but still low from the equilibrium value. The global kinetic model has been developed.

Special Presentation: 10 dry years in Melbourne, runs analysis and updated Köppen climate type map of the world

Since 1997, Melbourne has experienced 10 years of below median rainfall.  At the half way mark of 2007 an 11th year of below median rainfall appears likely.  In this presentation I will draw on recent research to discuss how likely runs of 10 and 11 dry years are with respect to Melbourne’s historical rainfall record.  Results from an investigation into whether Australia experiences longer and more severe dry periods than other locations around the world will also be presented and discussed.  And finally an updated Köppen climate map of the world will also be presented.

Special Presentation: 'Reconciling sampling inconsistencies in algal indicator data for long term trend assessment: A case study using effluent discharge monitoring in Victoria'

Victoria’s Eastern Treatment Plant (ETP), commissioned in 1975, is located approximately 40 km south-east of Melbourne’s CBD. It treats approximately 40% of Melbourne’s wastewater and has an average discharge flow of 370 megalitres per day. In 1997 Melbourne Water engaged the CSIRO to undertake an integrated study to investigate environmental impacts associated with effluent discharged from the ETP. The Study findings, combined with some earlier historical research, were used by the CSIRO Environmental Projects Office to develop a long-term monitoring program in 2000. Subsequently the Australian Centre for Environmetrics has undertaken an assessment of the intertidal algal monitoring data with the objective of detecting trends and changes that may be related to effluent discharge. Treated effluent discharges into Bass Strait at Boags Rocks, via a pipeline 56 km from the ETP, just below low tide mark. Due to the close proximity of the outfall to the surrounding intertidal habitats, this has been a focus area for impact assessment research and monitoring. Impacts on intertidal rock platform flora and fauna associated with the treated effluent have been studied by a variety of researchers using different sampling and analytical methods. Intertidal rock platforms up to 4km south-east and 21 km north-west of the outfall were first assessed in 1975 and 1976.  Platforms were not assessed again until 1980 after which time monitoring was sporadic and at least three distinct sampling methods were employed by a number of individuals and agencies. The lack of consistency in data collection poses a number of challenges for the analyst. In this talk we discuss a novel statistical approach to reconcile these inconsistencies so as to enable long-term trend assessments to be undertaken using the combined data.

Special Presentation: 'Sustainable storm water management in a megacity, Tokyo'

The stormwater infiltration facilities are in practice in many cities to reduce the stormwater peak flow as well as ground water recharge. There are many types of artificial stormwater infiltration mechanisms that have been practiced in urbanizing areas in order to decrease stormwater discharge to surface waters and help to preserve groundwater recharge. However, there is a considerable concern of their infiltration performance in a long run. At the same time there is concern of possible groundwater contamination since these infiltration system structures are usually not designed with any consideration for pollutants retention. Urban runoff pollutants (road runoff/ roof runoff) such as heavy metals and polycyclic aromatic hydrocarbons are trapped at the infiltration facilities and their deposition occurs slowly with time. Most of the heavy metals are soluble in low pH and they are readily mobilized. For example Zn and Cd are susceptible to low pH. Similarly the organic substances present in the sediment play important role in the adsorption and desorption of heavy metals, especially Cu and Pb. Within the sediment the different particle sizes have different heavy metals accumulating behavior.
 
The Tokyo Metropolitan Sewage Works experimentally applied infiltration facilities in some highly urbanized residential areas (1400 hectares) in Tokyo two decades ago in order to reduce the runoff water peak flows. The facilities include infiltration inlets, infiltration trenches and infiltration LU curbs, soakaways. The sediment deposited in the soakaways might have affected the infiltration performance. At the same time, prolonged deposition of micropollutants in the infiltration soakaways and change in the environmental conditions in the soakaways with time might have helped to release some of the heavy metals to the soil.
 
The research was focused on to evaluate the performance of infiltration facilities in different rainfall conditions after a long run and also to understand the behavior of micropollutants in the infiltration facilities, their possible leaching and threat to groundwater contamination.

PhD Final Presentation: 'A Bayesian network approach to natural resource management evaluation'

Governments, businesses and individuals invest millions of dollars each year into natural resource management. Historically, liHittle effort has been made to evaluate how effective this investment has been in achieving its stated outcomes because it has been difficult.  Difficulties arise in the evaluation of natural resource management because data and knowledge to support evaluation is sparse and dispersed; natural resource systems are complex and contain substantial and irreducible uncertainties; and management intervention is undertaken at a scale different to that at which management outcomes are assessed.  In addition, natural resource managers require confidence in the evaluation processes and results to maintain community support for their management strategies.
This presentation will describe an approach to the evaluation of natural resource management that overcomes many of the difficulties historically experienced.  The tool uses a combination of scientific and experiential knowledge to construct a Bayesian network model of the natural resource management system. The plausibility of the model is assessed by testing is structure against the understanding of natural resource managers and comparing model predictions available data describing the natural resource management system.  The model is then applied to management scenarios, representing condition with and without management intervention, and comparison of these scenarios enables the effectiveness of historical and future management intervention to be assessed.  The evaluation tool will be demonstrated through an application to Shepparton Irrigation Region Land and Water Management Plan.

PhD Final Presentation: 'Response of residential structures to blast vibrations'

Vibrations from blasting activities in mines and quarries in Australia may travel significant distances to houses where they have the potential to alarm residents and cause concern about their damage potential to houses.  The performance of residential structures to blast vibrations has been investigated through a series of monitoring and laboratory tests.  The final laboratory test has been a shaking table study of a full-scale brick veneer structure having characteristics typical of residential structures.  This test simulated more than 500 ground vibration traces from threshold levels through to levels responsible for causing substantial damage.  Vibrations within environmental limits were found to be neither responsible for causing cracking or capable of propagating existing cracks.  International standards are identified as more appropriate vibration limits to prevent cosmetic damage from vibrations.  A database developed for the Victorian Office of Housing has been developed and analysed at a population of 1000 properties damaged from normal environmental loads.  Results from this study and monitoring exercises demonstrate typical environmental factors exhibit greater damage potential than regulated blast vibrations.