School of Civil Engineering

Projects in coastal and environmental engineering

Project 1. Investigation of Lagoon stratification in Manihiki Atoll, Cook Islands

Supervisor:             Dr Remo Cossu r.cossu@uq.edu.au; Dr David Callaghan d.callaghan@uq.edu.au

Pearl farming is the major economy of many atolls in the Pacific Ocean and Manihiki, Northern Cook Islands, has one of the most famous pearl industries. However, occasionally the lagoon experiences failures when many oysters die and fail to produce pearls. The reason for this phenomenon is associated with poor water quality at the bottom of the lagoon. Field trips conducted in 2004, 2012, and 2016, have shown varying degrees of stratification in the lagoon water column with a high density, de-oxygenated bottom water layer and a low density, oxygenated upper layer. The relative thicknesses of these two water layers have varied through time with the depth of transition from low to high density water varying from 20 m to 50 m.

Field observations in 2016 revealed a two-layer stratification with warm, light water sitting on top of dense cool bottom water. The two water masses showed stable behaviour during the four-week field observation period. The mechanism driving the build-up of bottom water is still unclear. This project aims to analyse the data set and test two potential mechanisms for generation of bottom water: 1) hypersaline water forming through evaporation in shallow ponds around the reef edge, and 2) dense pools of ocean water entering the lagoon through wave flushing.

This project offers a great opportunity to understand important processes in lagoon systems. More importantly, this project provides work with real-world data sets and modern analysing techniques essential in many engineering applications. Student will gain knowledge of data processing software (Matlab) during the course of the project.

 

Project 2. Field observations of tidal flows in the lower Brisbane River and the Port of Brisbane

Supervisor:             Dr Remo Cossu r.cossu@uq.edu.au; Dr Alistair Grinham d.grinham@uq.edu.au

Tidal flows play an important role in the dynamics of many estuaries along Australia’s coastlines. Despite rapid development of the port facilities in Moreton Bay the knowledge of tidal dynamics near the mouth of the Brisbane River remains scarce. This project will use flow measurements from the Brisbane River to examine velocities fields and flow characteristics of the tidal flow and has direct applications to construction of port facilities and port management.

Acoustic Doppler Current Profilers (ADCPs) provide comprehensive data sets on flow characteristics in these environments. Profiles will be obtained from ship-mounted ADCPs in transects across and along the lower Brisbane River near the Port of Brisbane. The student will participate in field work and deployment of ADCPs, analysis of ADCP data and gain knowledge in essential hydrodynamics of coastal systems. This is a great opportunity to gain hands-on training in field work, data processing and theory to broaden your skill set in data analysis methods essential in coastal and environmental engineering applications.

Interest in fieldwork (e.g. boating) required. Student will gain knowledge of data processing software (Matlab) during the course of the project.

 

Project 3. Dye release experiments of ballast water in the Port of Brisbane, Moreton Bay, Queensland

Supervisor:             Dr Remo Cossu r.cossu@uq.edu.au

Ballast water discharge (BWD) from commercial cargo ships has been the dominant vector of biological invasions and poses a global threat to sensitive ecosystems. For instance, the Japanese seastar has colonized many Australian coastal waters and was introduced as an invasive species by ballast water release in Australian ports. International convention to regulate ballast water discharges was adopted to reduce ballast-mediated introductions globally, primarily through the use of physical and/or chemical treatment systems (IMO, 2004; Lloyd’s Register, 2010). Determining the proposed ballast water discharge standards is extremely difficult because threshold densities for successful establishment are unknown, and are likely species and system-specific.

The student will participate in dye release experiments and measure the dispersion of ballast water in the port of Brisbane. The non-toxic Rhodamine-WT tracer will be added to ballast water tanks before the water is discharged into the Brisane River and Moreton Bay. The fate of the ballast water will then be traced with a high-accuracy Rhodamine sensor to analyse concentration and spatial distribution of the tracer dye. This will aid in better understanding the diffusion and retention characteristics under various conditions (winds, waves, tides) in vicinity of the Port of Brisbane.

The student will participate in field work in Moreton Bay, analyse environmental parameters and gain a broad knowledge in marine hydrodynamics. This is a great opportunity to combine field work with theory and to broaden your skill set in data analysis methods required in coastal and environmental engineering applications.

Interest in fieldwork (e.g. boating) required. Student will gain knowledge of data processing software (Matlab) during the course of the project.

 

Project 4. Dye release experiments to investigate mixing dynamics in Moreton Bay

Supervisor:             Dr Remo Cossu r.cossu@uq.edu.au

This project will use a fluorescent dye (Rhodamine-WT tracer dye) to simulate dredge disposal propagation and ballast water propagation in Moreton Bay, Queensland. The Port of Brisbane dredges about 1 million m3 of sediments annually to guarantee navigational depths in the shipping channel. The dredge material is disposed near Mud Island (several kilometres south of the shipping channel) yet the fate of the sediments remains unknown.

The student will conduct dye release experiments and measure the dispersion of dredge material in Moreton Bay. The non-toxic Rhodamine-WT tracer will be added to the dredge material before the sediment is released at the disposal site. The dispersion of the dredge material will then be traced with a high-accuracy Rhodamine sensor to analyse concentration and spatial distribution of the tracer.

The student will participate in field work in Moreton Bay, analyse environmental parameters and gain a broad knowledge in marine hydrodynamics. This is a great opportunity to combine field work with theory and to broaden your skill set in data analysis methods required in coastal and environmental engineering applications.

Interest in fieldwork (e.g. boating) required. Student will gain knowledge of data processing software (Matlab) during the course of the project.

 

Project 5. Field observations of ship-induced sediment transport near the Port of Brisbane

Supervisor:             Dr Remo Cossu r.cossu@uq.edu.au; Dr Alistair Grinham a.grinham@uq.edu.au

Despite rapid development of the Port of Brisbane the knowledge of sediment transport dynamics in Moreton Bay is limited. Ship-induced erosion is considered a major contributor to sediment resuspension and movements in waterways, ports and shallow coastal areas. Ships generate water jets and waves which induce shear-stresses on the seafloor large enough to erode particulate matter which can change the morphodynamics, e.g. the navigational depths of waterways. However, the direct impact of ships on sediment resuspension is difficult to measure. Due to the economic demand container vessel dimensions are increasing. Consequently, the interference with nature by these vessels increases as well. The shipping channel of the Port of Brisbane extends for > 50 km and is a unique study site in Australia to measure ship-induced resuspension events in shallow areas and to gain more insight into the dynamics that drive the resuspension process.

This project will use field observations of suspended sediment in the wake of large container vessels to quantify parameters to describe and predict sediment movements in the shipping channel. This is a great opportunity to learn more about one of Australia’s fasted growing ports and hands-on experience in coastal engineering.

Interest in fieldwork (e.g. boating, scientific instruments) required. Student will gain knowledge of data processing software (Matlab) during the course of the project.

 

Project 6. Measurements of tidal currents and Reynolds stress profiles in stratified/unstratified tidal flows

Supervisor:             Dr Remo Cossu r.cossu@uq.edu.au

Turbulence in the presence of stratification and shear plays an important role in the dynamics of shallow tidal flows in many estuaries. Acoustic Doppler Current Profilers (ADCPs) provide comprehensive data sets on flow characteristics in these environments. This project will use ADCP measurements taken in the lower Brisbane River over several tides (days) to examine flow and turbulent characteristics (water velocities, shear stresses, mixing) of the tidal flow. Profiles of relevant parameters will be calculated from these measurements and could be compared to observations obtained in similar environments.

The student will participate in the preparation and deployment of shallow water moorings, analyse ADCP data and gain knowledge in coastal engineering processes. This is a great opportunity to combine fieldwork with theory and to get valuable experience in real world data analysis required in civil and environmental engineering applications.