Tim John Peterson

Tim John Peterson
University of Melbourne | MSD · Department of Infrastructure Engineering

PhD, BEnvEng, BSc

About

52
Publications
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824
Citations

Publications

Publications (52)
Presentation
Full-text available
Question #20 of the UPH aspires to disentangle and reduce model prediction uncertainty. One feasible approach is to first formulate the relationship between variability (of real-world hydrological processes and catchment characteristics) and uncertainty (of model components and variables), which links the UPH theme of “modelling methods” to “time v...
Conference Paper
Full-text available
Hydrological models are conventionally evaluated in terms of their response surface or likelihood surface constructed with the model parameter space. To evaluate models as hypotheses, we developed the method of Flux Mapping to construct a hypothesis space based on model process representation. Here we defined the hypothesis space based on dominant...
Poster
Full-text available
While scientific hypotheses are our best tools to represent and understand real world phenomena, we know a priori that all hypotheses are incomplete and uncertain. Particularly in domains such as Earth and environmental sciences, given the exuberance of uncertainty and inexactness associated with every step of the scientific inquiry. No single hypo...
Article
In contrast to management optimisation methods, which quantify decision variables to create plans, this study does not seek the “best” strategy. Instead, it simulates the sequential decision-making process implicit in environmental management, so that the effectiveness of management scenarios, when implemented as intended, can be evaluated. The pur...
Article
Full-text available
Uncertainty analysis is an integral part of any scientific modeling, particularly within the domain of hydrological sciences given the various types and sources of uncertainty. At the center of uncertainty rests the concept of equifinality, i.e. reaching a given endpoint (finality) through different pathways. The operational definition of equifinal...
Conference Paper
Full-text available
All models are wrong, all data are erroneous, our knowledge of real-world processes is fallible, and all model evaluations are incomplete. Despite these limitations, there is room to improve models and evaluation schemes, and due to these limitations uncertainty is an inalienable property of scientific modelling. At the heart of uncertainty lies th...
Article
Groundwater observation bores are often monitored irregularly and infrequently. The resulting groundwater hydrographs are consequently less informative for understanding groundwater level trends, seasonality, flow directions, drawdown, and recovery. This paper presents an approach to temporally interpolate a groundwater hydrograph that has an irreg...
Conference Paper
Full-text available
Conceptual hydrologic models, such as rainfall-runoff models (RRMs), are simplified representations of real-world systems. Conventionally, their performance and predictive capability is evaluated through pair-wise comparison of simulated and observed streamflow (i.e. aggregated response of the catchment system), accompanied by uncertainty and/or se...
Conference Paper
Full-text available
Equifinality is understood as one of the fundamental difficulties in the study of open complex systems, including catchment hydrology. A review of the hydrologic literature reveals that the term equifinality has been widely used, but in many cases inconsistently and without coherent recognition of the various facets of equifinality, which can lead...
Article
Full-text available
Suspicious groundwater-level observations are common and can arise for many reasons ranging from an unforeseen biophysical process to bore failure and data management errors. Unforeseen observations may provide valuable insights that challenge existing expectations and can be deemed outliers, while monitoring and data handling failures can be deeme...
Chapter
Water quality is a fundamental aspect of aquatic ecosystems, defining the conditions for aquatic flora. changes in water quality may result in immediate changes int he structure and function of ecosystems and have significant effects on other water values and usages. The influences of anthropocentric and natural factors on water quality and quantit...
Article
Estimation of baseflow from streamflow hydrographs has been a major challenge in hydrology for decades, leading to developments of baseflow separation filters. When without tracer or groundwater data to calibrate the filters, the standard approach to apply these filters in practice involves some degrees of subjectivity in choosing the filter parame...
Article
Full-text available
Groundwater is the world's largest freshwater resource and due to overextraction, levels have declined in many regions causing extensive social and environmental impacts. Groundwater management seeks to balance and mitigate the detrimental impacts of development, with plans commonly used to outline management pathways. Thus, plan efficiency is cruc...
Article
Recursive digital filters (RDFs) are widely used for estimating base flow from streamflow hydrographs, and various forms of RDFs have been developed based on different physical models. Numerical experiments have been used to objectively evaluate their performance, but they have not been sufficiently comprehensive to assess a wide range of RDFs. Thi...
Article
Full-text available
Hydrologic models have potential to be useful tools in planning for future climate variability. However, recent literature suggests that the current generation of conceptual rainfall runoff models tend to underestimate the sensitivity of runoff to a given change in rainfall, leading to poor performance when evaluated over multi-year droughts. This...
Article
Full-text available
Groundwater time-series modeling has emerged as an efficient approach for simulating the impacts of multiple drivers of groundwater-head variation such as rainfall, evaporation and groundwater pumping. However, a bottom-up approach has generally been adopted whereby the input drivers have been assumed without statistical evidence for their inclusio...
Article
Estimation of aquifer hydraulic properties is essential for predicting the response of an aquifer to extractions and hence estimating the availability of the groundwater resources. Aquifer tests are commonly used for the estimation of aquifer properties; however they can be expensive and often only characterize the short-term response of the aquife...
Article
Full-text available
Time-series modeling is often used to decompose groundwater hydrographs into individual drivers such as pumping and meteorological factors. To date, there has been an assumption that a simulation fitting the total hydrograph produces reliable estimates of the impact from each driver. That is, assessment of the decomposition has not used an independ...
Article
Full-text available
Groundwater discharge is a major contributor to stream baseflow. Quantifying this flux is difficult, despite its considerable importance to water resource management and evaluation of the effects of groundwater extraction on streamflow. It is important to be able to differentiate between contributions to streamflow from regional groundwater dischar...
Article
Full-text available
Groundwater discharge is a major contributor to stream baseflow. Quantifying this flux is difficult, despite its considerable importance to water resource management and evaluation of the effects of groundwater extraction on streamflow. It is important to be able to differentiate between contributions to streamflow from regional groundwater dischar...
Article
This paper presents a nonlinear transfer function noise model for time-series modeling of unconfined groundwater hydrographs. The motivation for its development was that existing groundwater time-series models were unable to simulate large recharge events and multi-year droughts. This was because existing methods do not partition rainfall to runoff...
Article
A commonly accepted paradigm in environmental flow management is that a regulated river flow regime should mimic the natural hydrological regime to sustain the key attributes of freshwater ecosystems. Estimation of the environmental risk arising from flow regulation needs to consider all aspects of the flow regime when applied to water allocation d...
Article
The companion paper showed that multiple steady state groundwater levels can exist within a hill-slope Boussinesq-vegetation model under daily stochastic forcing. Using a numerical limit-cycle continuation algorithm, the steady states (henceforth attractors) and the threshold between them (henceforth repellor) were quantified at a range of saturate...
Article
Including positive feedbacks in hydrological models has recently been shown to result in complex behavior with multiple steady states. When a large disturbance, say a major drought, is simulated within such models the hydrology changes. Once the disturbance ends the hydrology does not return to that prior to the disturbance, but rather, persists wi...
Conference Paper
Full-text available
Groundwater discharge is a major contributor to stream baseflow and quantifying this flux is of considerable importance to water resource management. It can be estimated using tracers, water balance studies and numerical modelling, but insufficient use is made of groundwater level observations and water table mapping. We illustrate a method that ma...
Conference Paper
Full-text available
Mapping of groundwater level observations often makes very little use of auxiliary data and is often undertaken simply by manual interpolation or ordinary kriging of the heads. However, heads are influenced by numerous other drivers that cannot be account for by such methods. Such drivers include the land cover type, aquifer basement elevation and...
Conference Paper
For many decades, throughout much of Australia, considerable public investment has been made in establishing and monitoring groundwater bores. To improve the value extracted from this data set, a new, and statistically robust, hydrograph time-series modelling framework was developed. It extends an existing transfer function-noise model by inclusion...
Conference Paper
Full-text available
The vast majority of hydrogeological modelling has implicitly assumed only one steady state can exist. However, recent work has shown that including positive feedbacks in hydrological models can result in complex behaviour with multiple steady states and a finite resilience from a single parameter set. More generally, this is typical of systems wit...
Article
This paper describes a new global damage identification framework for the continuous/periodic monitoring of civil structures. In order to localize and estimate the severity of damage regions, a one-stage model-based Bayesian probabilistic damage detection approach is proposed. This method, which is based on the response power spectral density of th...
Conference Paper
Full-text available
Identifying the contribution of groundwater discharge to stream baseflow is of considerable importance for maintaining environmental flows and determining the potential effects of groundwater pumping on streamflow. The 'Rating Curve' method (Gonzales et al., 2009) is one of the few techniques that make empirical use of groundwater data by generatin...
Conference Paper
Recent work has shown that including positive feedbacks in hydrological models can result in complex behavior with multiple steady states (henceforth attractors) and a finite resilience from a single parameter set. More generally, this is typical of systems with positive feedbacks. However, a limitation of past studies is that multiple attractors w...
Conference Paper
Full-text available
The dynamics of unconfined groundwater levels are usually the result of numerous and interacting factors, such as land cover change, climate variability and groundwater pumping. Estimating the impact from pumping is highly significant for resource management but also very challenging. A variety of methods are used to model water-table dynamics infl...
Conference Paper
This paper presents an advanced probabilistic water table mapping algorithm. It facilitates inclusion of a wide range of quantitative and qualitative knowledge to improve the interpolation of water table data between sparse observation wells. The motivation for developing it was that water table mapping often makes little use of auxiliary data and...
Article
Full-text available
Our understanding of short- and long-term dynamics of spatial soil moisture patterns is limited due to measurement constraints. Using new highly detailed data, this research aims to examine seasonal and event-scale spatial soil moisture dynamics in the topsoil and subsoil of the small spruce-covered Wustebach catchment, Germany. To accomplish this,...
Article
Full-text available
In recent years a number of papers have quantitatively explored multiple steady states and resilience within a wide range of hydrological systems. Many have identified multiple steady states by conducting simulations from different initial state variables and a few have used the more advanced technique of equilibrium or limit cycle continuation ana...
Conference Paper
Full-text available
The dynamics of groundwater levels within unconfined aquifers are often the result of numerous and interacting factors, such as land cover change, climate variability and groundwater pumping. For such unconfined aquifers, estimating the impact from pumping is highly significant for resource management but also very challenging. To date, in Australi...
Conference Paper
Full-text available
Mapping of groundwater level observations often makes very little use of auxiliary data and is often undertaken simply by manual interpolation or ordinary kriging of the heads. Recently, a number of geostatistical methods have emerged that significantly improve estimates by incorporating the land surface elevation and groundwater flow or drawdown e...
Conference Paper
Full-text available
A number of groundwater hydrograph time series models have been proposed over recent years but, to our knowledge, there has been no systematic review of their performance and thus no means of selecting a model to suit the prevailing conditions. This paper presents an evaluation of the new groundwater hydrograph time series models presented in Peter...
Conference Paper
Full-text available
This paper details a novel numerical method for automatic estimation of stream meander length. It is based upon Langbein et al. (1966) and produces a single meander length and meander amplitude over a given reach that minimises the least-squares error. This algorithm has been applied to 1,456 reach segments, each approximately of 1 km flow path, th...
Conference Paper
Full-text available
For many decades, throughout much of Australia, considerable public investment has been made in establishing and monitoring groundwater bores. To improve the value extracted from this data set, this paper presents a new, and statistically robust, hydrograph analysis method. It extends an existing transfer function-noise model by inclusion of a deri...
Conference Paper
Full-text available
Many physically based models of surface and groundwater hydrology are constructed without the possibility of multiple stable states for the same parameter set because they do not include positive feedbacks. For such a conceptualisation, at the cessation of a transient hydrological disturbance of any magnitude the model will return to the initial st...
Article
Full-text available
Many physical-based models of surface and groundwater hydrology are constructed without the possibility of multiple stable states for the same parameter set. For such a conceptualization, at the cessation of a transient hydrological disturbance of any magnitude the model will return to the same stable state and thus show an infinite resilience. To...
Conference Paper
Full-text available
A numerical distributed eco-hydrological model (coupled hillslope Boussinesq-vertically lumped vadose zone) has been developed in which qualitatively different steady state (attractor) water table elevations (shallow and deep) exist for the same parameter set and is used here to analyse catchment resilience to climatic disturbances. Traditional res...
Conference Paper
Many physical based models of surface and groundwater hydrology are constructed without the possibility of multiple stable states for the same parameter set because they do not include positive feedbacks. For such a conceptualization, at the cessation of a transient hydrological disturbance of any magnitude the model will return to the same stable...
Article
Full-text available
Many models of surface and groundwater hydrol-ogy are constructed without thought given to the possibility of multiple stable states for the same parameter set. If a single stable state is assumed, a transient hydrological disturbance of any magni-tude will result in a return of the model to the same stable state, and thus show an infinite resilien...
Conference Paper
Full-text available
Over the last decade, many ecosystems have begun to be understood as having multiple coexistent stable states. Often such states are characterized as socially desirable and undesirable, with for instance high/low fish stocks or oligotrophic / eutrophic lake states. Within catchment planning modeling, a frequent assumption is that the equilibrium st...
Conference Paper
Full-text available
EXTENDED ABSTRACT Over the last decade, ecosystem management has been tending toward understanding ecosystems as having multiple stable states. Often such states are characterised as socially desirable and undesirable, with for instance high/low fish stocks or oligotrophic/eutrophic lake states. Their significance is that small stochastic forces ma...
Conference Paper
Full-text available
Salinity management relies heavily upon the mapping of the watertable to predict regions at risk of salinity. Current mapping techniques often ignore the influence of topographic and interpolate using only the reduced water level (RWL) at each bore. This paper builds on Peterson et al [2003] which addresses the above deficiencies using an advanced...
Conference Paper
Full-text available
Salinity management relies heavily upon the mapping of the depth to the water table to predict regions at risk of salinity. Current mapping techniques often ignore the influence of topography and interpolate using only the reduced water level (RWL) at each bore. The result, frequently, is an exaggerated area of shallow watertable and area apparentl...
Conference Paper
Full-text available
Salinity management relies heavily upon the mapping of the watertable to predict regions at risk of salinity. Current mapping techniques often ignore the influence of topography to interpolate using only the reduced water level (RWL) at each bore. The result, frequently, is an exaggerated area of shallow watertable and as such salinity risk. Curren...

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Projects

Projects (4)
Project
Scientific modeling of open complex systems in the face of uncertainty
Project
- Quantify the catchment response and recovery to the Millennium Drought across Victoria - Identify the mechanism(s) for the observed response and recovery from prolonged droughts
Project
Analyse long-term trends in rainfall-streamflow relationships across Australia