Rodger Benson Tomlinson

Comparison of Fuzzy-AHP and AHP in a spatial multi-criteria decision making model for urban land-use planning

Modern planning theories encourage approaches that consider all stakeholders with a variety of discourse values to avoid political and manipulative decisions. In the last decade, application of quantitative approaches such as multi-criteria decision making techniques in land suitability procedures has increased, which allows handling heterogeneous data. The majority of these applications mainly used decision-making techniques to rank the priority of predefined management options or planning scenarios. The presented study, however, shows how spatial decision-making can be used not only to rank the priority of options and performing scenario analysis, but also to provide insight into the spatial extent of the alternatives. This is particularly helpful in situation where political transitions in regard to urban planning policies leave local decision-makers with considerable room for discretion. To achieve this, the study compares the results of two quantitative techniques (analytical hierarchy procedure (AHP) and Fuzzy AHP) in defining the extent of land-use zones at a large scale urban planning scenario. The presented approach also adds a new dimension to the comparative analysis of applying these techniques in urban planning by considering the scale and purpose of the decision-making. The result demonstrates that in the early stage of the planning process, when identifying development options as a focal point is required, simplified methods can be sufficient. In this situation, selecting more sophisticated techniques will not necessarily generate different outcomes. However, when planning requires identifying the spatial extent of the preferred development area, considering the intersection area suggested by both methods will be ideal.

Uncertainty analysis in the application of multi-criteria decision-making methods in Australian strategic environmental decisions

Multi-criteria decision-making techniques have become increasingly widespread in strategic environmental decision making. In Australia, these techniques are used to integrate both conservation and development aspects of natural resource use. MCDM can also evaluate the effects of uncertainties at each stage of the decision-making process and examine the sensitivity of results to the inputs. This paper reviews the potential uncertainties in environmental management decision-making procedures and explores how uncertainty analysis in the framework of MCDM can address some of these uncertainties. It then examines the application of MCDM in 16 Australian case studies to determine how uncertainty has been addressed in practice. Results demonstrate that appropriate use of MCDM can address uncertainties associated with decision-makers’ preferences and from using different techniques (epistemic uncertainty). Results also highlighted the need for incorporating visualising techniques, such as GIS and simulation algorithms (e.g. Monte Carlo simulations), to examine the effects of uncertainty on the spatial pattern of the outcomes. This approach also presents promising ways to gain an understanding of the effects of some dimensions of stochastic uncertainty, and assists in increasing the transparency of the decision-making process.

Marine Ecosystem Enhancement on a Geotextile Coastal Protection Reef - Narrowneck Reef Case Study -

The Narrowneck Artificial Reef [Gold Coast, Australia] was constructed in 1999/2000 out of large sand-filled geotextile containers. It quickly became evident that the containers provided an excellent substrate for marine flora and the development of a diverse ecosystem. As a result, the reef has become popular with locals for fishing, diving, snorkeling and spearfishing. In the years since it was constructed, monitoring of the ecological aspects of the reef has been undertaken. While macroalgae and pelagic fish dominate the reef, it is also home to a wide variety of benthos, fish and other marine fauna. Influenced by the East Australia Current and wave action from the Pacific Ocean, driven by the South East Trade Winds, the reef exhibits a different community structure in comparison to other natural reefs of the Gold Coast. The popularity of the Narrowneck Reef has clearly shown that enhancing the ecological environment and improving recreational amenity have potential benefits on eco-tourism as well as local biodiversity.

Assessment of Post-Storm Recovery of Beaches Using Video Imaging Techniques: A Case Study at Gold Coast, Australia

Ever-expanding networks of surf cameras offer a unique opportunity to monitor the coastline over large expanses at very little cost compared to traditional in situ survey methods. Here, we describe and test a new coastal monitoring system maintained by CoastalCOMS Pty Ltd. at their test site at Gold Coast, Australia. The two-camera system monitors two highly sensitive 4-km stretches of sandy coastline adjacent to high-value assets. The traditional static multi-camera setup has been replaced by a single rotational camera. A 14-month data set, encompassing one major storm, a recovery period, and a seasonal cycle, was analyzed. Positive shoreline detections using the new camera system were available 64% of the time (roughly 145 days of the available 226, where daily offshore significant wave heights Hs ≤ 1 m). Comparison of the CoastalCOMS-derived shorelines and in situ survey data showed a mean shoreward bias of 25.5 m. Daily shoreline estimates were used to calculate weekly and five-week running mean beach widths at both sites. Analysis showed that both sites eroded between 15-22 m during the May 2009 storm and then recovered during the proceeding five-month calm period. Distinct intersite variability was observed between the more exposed Northern Beaches that displayed an annual shoreline cycle and very little intrasite variability and the more sheltered southern Palm Beach site that displayed large intrasite spatial variability and sensitivity to changes to both wave direction and wave height.

Monitoring of a multifunctional submerged geotextile reef breakwater

A large reef has been constructed offshore from Narrowneck on the Gold Coast, Queensland, Australia. The reef provides a submerged, low visual impact, coastal control point to stabilize the nourished northern Gold Coast beaches. As the reef is in a popular tourist and surfing area, it has also been designed and constructed to enhance recreational amenity. For safety and cost efficiency, the reef has been constructed of very large sand filled geotextile units. Experience with the design and construction of such structures is limited and the inclusion of improved surfing as secondary design criteria increases the complexity. To facilitate evaluation and modifications to the reef there is a comprehensive monitoring program, which includes the use of ARGUS video imagery to assess the changes in the shoreline related to wave conditions at the wave rider buoy nearby. Divers are studying the physical performance of the sand filled geotextile containers, as well as the extent and diversity of the marine ecosystem which has exceeded expectations. There have been a number of storm wave events during the monitoring period. The data obtained from the monitoring is being used to modify the long term Narrowneck reef shape, and to design other proposed reefs in the area.

Observation and Analysis of Hydrodynamic Parameters in Tidal Inlets in a Predominantly Semidiurnal Regime

Abstract Gold Coast Seaway and Jumpinpin Bar are two tidal inlets that connect the Pacific Ocean to the extensive Gold Coast estuarine system. While the Gold Coast Seaway has been stabilized in the mid-1980s by two rock walls, Jumpinpin Bar has remained a highly dynamic tidal inlet. A detailed study of these two tidal inlets is overdue and has been hindered for a long time by the lack of comprehensive field data. This study provides an extensive hydrodynamic data set, which on one side provides an insight into the hydrodynamic behavior of these two tidal inlets and on another side provides a base for their further study. The measured data show relatively high flow velocities at both locations exceeding 2 m/s. It also shows a strong spatial asymmetry in flow velocity distribution across the Gold Coast Seaway during the ebb tide, which accounts for some of the morphological changes at the study area. A five-month water-level measurement indicates a mixed, predominantly semidiurnal tidal regime at these tidal inlets. Examination of tidal variation shows minor temporal tidal asymmetry at both inlets with potential impact on the sediment transport regime at the inlets. In terms of stability, investigation into the tidal prism and cross-sectional area relationship for both inlets can be described using existing relationships obtained from regression analysis of tidal inlets on Pacific and Atlantic coasts. In regards to stability analysis based on tidal prism–littoral drift relationship, the Gold Coast Seaway seems to be approaching stability while Jumpinpin Bar seems to be more of a dynamic inlet.

Empirical Estimation of Nearshore Waves From a Global Deep-Water Wave Model

Global wind-wave models such as the National Oceanic and Atmospheric Administration WaveWatch 3 (NWW3) play an important role in monitoring the worlds oceans. However, untransformed data at grid points in deep water provide a poor estimate of swell characteristics at nearshore locations, which are often of significant scientific, engineering, and public interest. Explicit wave modeling, such as the Simulating Waves Nearshore (SWAN), is one method for resolving the complex wave transformations affected by bathymetry, winds, and other local factors. However, obtaining accurate bathymetry and determining parameters for such models is often difficult. When target data is available (i.e., from in situ buoys or human observers), empirical alternatives such as artificial neural networks (ANNs) and linear regression may be considered for inferring nearshore conditions from offshore model output. Using a sixfold cross-validation scheme, significant wave height Hs and period were estimated at one onshore and two nearshore locations. In estimating Hs at the shoreline, the validation performance of the best ANN was r=0.91, as compared to those of linear regression (0.82), SWAN (0.78), and the NWW3 Hs baseline (0.54)

Video-imaging of transient rip currents on the Gold Coast open beaches

ABSTRACT Murray, T., Cartwright, N., Tomlinson, R., 2013. Video-imaging of transient rip currents on the Gold coast open beaches. Transient rips vary in location and occurrence making them hard to predict, and unlike topographically controlled, fixed or semi-permanent rips, they are believed to be controlled by surf zone hydrodynamics rather than beach and surf zone morphology. This paper reports on the first video analysis of transient rip behaviour in the Southern Hemisphere. Transient rips were identified from a high camera located approximately 100 m above mean sea level at Narrowneck, Gold Coast, Australia. Transient rip occurrence, duration and flow behaviour were identified from the video and occurrence was correlated with environmental factors including beach state, wave, tide and wind characteristics. Transient rips were found to display a mushroom cloud rip head and a narrow trailing rip neck consistent with characteristics often displayed by topographically controlled rips. Transient rip events were characterised by short life-spans (30 – 236 s) and low temporal frequency, but high temporal variance, occurring for only 0.52% of the time in the video. Around 66% of transient rip events identified occurred when the beach was generally alongshore uniform in a shore-attached terrace state. Transient rip occurrence was also found to be significantly greater on the ebb tide as opposed to the flood tide and when wave breaking was absent on the outer bar. There was a lack of a clear correlation between averaged wave and wind conditions and transient rip formation. Current and future study is focussing on the effects of wave groupiness and sea state on transient rip occurrence, spacing, duration and intensity.

Towards an Integrated Ecosystem-Based Bioaccumulation and Metal Speciation Model

Heavy metal bioaccumulation models are important for interpreting water quality data, predicting bioaccumulation in organisms, and investigating the provenance of contaminants. To date they have been predominantly used as single-issue models, under steady-state conditions and in isolation of the biogeochemical processes that control metal bioaccumulation. Models that incorporate these processes would allow a more holistic approach to bioaccumulation modeling and contaminant assessment; however, this has been rarely undertaken, probably because it requires the integration of inter-disciplinary areas. In this study, we have developed such a model that integrates three key multi-disciplinary areas (biological, metal speciation, and bioaccumulation processes) and responds to variations in temporal external and internal forcing. Furthermore, spatial context is provided by developing the model within a simple hydrodynamic box-modeling framework. The calibrated model was able to predict with reasonable accuracy the temporal and spatial trends of soft-tissue copper bioaccumulation in a coastal oyster. This exploratory model was also used to highlight the importance of phytoplankton as an important vector of copper uptake dynamics by an oyster, therefore reinforcing the importance of the integrated approach. Finally, our model provides a framework for greater application beyond this specific example such as in the areas of waterway restoration, which has been shown to be an important area of ecological and environmental research.

Opportunistic management of estuaries under climate change: A new adaptive decision-making framework and its practical application

Ongoing coastal development and the prospect of severe climate change impacts present pressing estuary management and governance challenges. Robust approaches must recognise the intertwined social and ecological vulnerabilities of estuaries. Here, a new governance and management framework is proposed that recognises the integrated social-ecological systems of estuaries so as to permit transformative adaptation to climate change within these systems. The framework lists stakeholders and identifies estuarine uses and values. Goals are categorised that are specific to ecosystems, private property, public infrastructure, and human communities. Systematic adaptation management strategies are proposed with conceptual examples and associated governance approaches. Contrasting case studies are used to illustrate the practical application of these ideas. The framework will assist estuary managers worldwide to achieve their goals, minimise maladaptative responses, better identify competing interests, reduce stakeholder conflict and exploit opportunities for appropriate ecosystem restoration and sustainable development.