School of Geography PhD thesis projects in fluvial geomorphology and river processes (commencing 2016). For any information about these research projects, contact Ian Rutherfurd ([email protected]). Thesis topic 1 Improving the design and environmental values of mining stream diversions in the Eastern Pilbara (Western Australia) by understanding the geomorphology and hydrology of natural anabranching streams. Field location: The Pilbara region of the remote North West of Western Australia. Sponsor: BHP Billiton Iron Ore Pty Ltd (BHPBIO) Supervisors: This PhD project would be supervised by Associate Professor Ian Rutherfurd (School of Geography, the University of Melbourne), and Associate Professor Mike Stewardson (Infrastructure Engineering, University of Melbourne). Skills required: It would be advantageous to have the following skills (or a strong interest in developing them): adequate hydrological and hydraulic modelling, fluvial geomorphology, river engineering, capacity for sustained field work in remote (but regulated) locations, sediment transport modelling, geotechnical modelling, basic ARC-GIS skills, and capacity to work in a small team.

We would encourage students with excellent skills in one or more of the following areas to apply: fluvial geomorphology, river engineering, geo-technical engineering, river hydrology, geography, environmental science, or similar fields. Support: The applicant will apply for a post-graduate scholarship through the Science Faculty of the University of Melbourne. Depending on the quality of the applicant, and if they are successful in winning a scholarship (scholarship success rate for eligible candidates in 2014 was around 40%) they could receive a cash top-up to their stipend. The student will also receive a lap-top computer, and funding support to attend conferences during their candidature. All costs of the project are covered by support from the sponsor (this includes flights to remote locations, and field accommodation). Project description It is now becoming more common to divert rivers and creeks in order to access minerals under the river bed (usually coal or iron-ore). BHP Billiton Iron Ore Pty Ltd (BHPBIO) mines iron ore from channel iron deposits in the Eastern Pilbara of Western Australia. The long-term development plan for the region involves options to construct many diversions (from one kilometre to tens of kilometres in length) over the long life of its mines in the Eastern Pilbara. Best practice in river diversions is now to construct streams that retain the basic characteristics of the channel that they replaced rather than simply creating an artificial trench. Such a channel should transmit water and sediment through without having unusual levels of erosion (i.e. they should be ‘dynamically stable’). Mimicking as far as possible the character of the original channel both reduces future maintenance costs, as well as assisting with licensing from regulators. Thus, as far as practical, BHPBIO is aiming for any diverted sections of creek to perform in a similar manner to the existing creek that they replace. This performance extends beyond the hydraulic function of the creek to include sediment transport and ecological functions. This project is concerned with the geomorphological character of diversions, and their geo-technical stability, rather than their biology. The challenge in the Eastern Pilbara is that the streams that will be diverted are sand and gravel bedded, anabranching streams, that experience highly variable arid-zone tropical hydrology. Although anabranching streams are common across the arid-zone of Australia, they have not been well studied. Understanding the basic geomorphology of the streams will assist BHPBIO in the design of mining diversion channels. The intention would be to develop guidelines that can be used to design diversion channels. Preliminary work has already been commissioned by BHPBIO on the geomorphology of Marillana Creek in relation to a major 20 km diversion. This study described the geomorphology and hydrology of a single large anabranching channel. It identified the interaction of hydrology, hydraulics, channel width (as controlled by geology/structure), and vegetation in controlling the anabranching morphology of Marillana Creek. The consulting project provides a starting point for the study proposed here on smaller anabranching streams. This study would investigate potential diversion channels around small anabranching tributaries of the Eastern Pilbara (i.e. streams with catchment areas between 20 and 500 km2). The specific questions that could be considered in this project include: 1. What lessons can be learned from existing mining stream diversions around Australia and the world for the design of diversions in the Eastern Pilbara?

2. How can we improve the understanding of peak flow hydrology for small Eastern Pilbara streams (<500 km2) based on data that has been collected by BHP and by government agencies? 3. Can paleo-flood indicators such as slack-water deposits, and boulder deposits, be used to extend the instrumental flood peak (and possibly frequency) record in these streams? This will improve understanding of the type of flood events that diversion channels will need to be designed for. 4. What are the basic geomorphological controls on the channel characteristics (i.e. width, depth, particle size, character of anabranching) of streams in the Eastern Pilbara? These characteristics would be identified by mapping and comparing the morphology of multiple anabranching channels in the region from LiDAR data and aerial photography. Controls would likely include: slope, width, lithology, and catchment area. 5. Can we improve understanding of the processes that form the key geomorphic features of anabranching channels (including: the relationship between hydrology and stream dimensions, controls on stream shape (width and depth), benches, and floodplains). These are all features that could be expected to develop in artificial diversions with time. 6. What is the life-cycle of key geomorphic features of anabranches (creation and destruction) (including the interaction with sediment transport and vegetation)? 7. Can this understanding of geomorphology be expressed as rules of thumb and designguidelines that can assist BHPBIO in constructing effective diversions at minimal cost? 8. Can existing diversion channels provide tests of the rules-of-thumb and design guidelines developed from studying natural channels? Research Environment The University of Melbourne has an active program in river and water related research. This spans from fluvial geomorphology, river management, and environmental reconstruction, in the School of Geography, to river engineering, hydrology, and environmental flows in the Department of Infrastructure Engineering. You will join a lively team of post-graduate students working on related projects.

PhD Topic number 2 Identifying the influence of riparian vegetation in trapping sediment and nutrients on alluvial surfaces in rivers of SE Queensland. Field location: Streams draining into Moreton Bay, South East Queensland, Australia (note that the student will be based in Melbourne, but would be spending blocks of time in Brisbane). Sponsor: Australian Research Council Linkage Grant (co-sponsored by SEQwater) Skills required: This is a multi-disciplinary project and it would be advantageous to have the following skills (or a strong interest in developing them): capacity to develop basic hydrological and hydraulic models, fluvial geomorphology, river engineering, capacity for sustained (and self-directed) field work, basic sediment transport modelling, geotechnical modelling, basic ARC-GIS skills, and capacity to work in a small team. You would be fully trained to carry-out basic laboratory analyses to date sediments using optically stimulated luminescence (OSL). We would encourage students with excellent skills in one or more of the following areas to apply for this position: fluvial geomorphology, river engineering, geo-technical engineering, river hydrology, geography, environmental science, environmental chemistry, or related disciplines. Supervisors: This PhD project would be supervised by Associate Professor Ian Rutherfurd (University of Melbourne), and Professor Jon Olley (ARI, Griffith University). Support: The applicant will apply for a post-graduate scholarship through the Science Faculty of the University of Melbourne. Depending on the quality of the applicant, and if they are successful in winning a scholarship (scholarship success rate for eligible candidates in 2014 was around 40%) they could receive a cash top-up to their stipend. The student will also receive a lap-top computer, and funding support to attend conferences during their candidature. All costs of the project are covered by support from the sponsor (this includes flights, and field accommodation). Project description Sediment and nutrients from agricultural catchments in SE Queensland threatens the health of Moreton Bay, as well as the water supply of the city of Brisbane. The regional water authority (SEQwater) is committed to protecting water supply by establishing catchment riparian vegetation that will both reduce erosion rates, and trap sediment, before it reaches the waterway. SEQwater have partnered with Griffith University, and the University of Melbourne, in a research project to establish: “exactly where should we establish riparian vegetation in the region to optimize the reduction in sediment yield from the catchments, how can this vegetation be established cost effectively, and how can it be maintained with minimum cost in the face of floods and weeds?” A team of geomorphologists and ecologists are working on the project.

The specific part of the project that is covered by this PhD project involves identifying the influence of riparian vegetation in trapping, and stabilising sediment on alluvial surfaces in rivers of SE Queensland. The following approaches are suggestions only. The student might decide to approach the problem from a different direction. Sediment, and its associated nutrients, is stored on a variety of surfaces and geomorphic units within the bed, banks and macro-channel of SE Queensland streams. Sediment is also released from these stores by erosion. This project will explore the volume of fine sediment stored on these surfaces relative to the total sediment load of the river, it will also explore when sediment is deposited or eroded from these stores. The goal is to express sediment flux for specific surfaces (geomorphic units), with and without specific riparian vegetation communities. The flux is most easily expressed as a trap-efficiency per unit length of river for different riparian management options. This flux can then be related to specific management problems, particularly around potable water supply. Note that this can be considered as a gross budget problem, or as a more complicated event (stochastic) step-length problem. Recent research reported by Pizzuto (2014) uses mercury as a tracer to demonstrate that a pulse of suspended sediment travels an average of only 10km before being stored – a much shorter distance than previously thought. Recent work in Queensland (Hughes et al. 2010) also demonstrates the large proportion of sedimentation that takes place on instream benches and surfaces. All of the geomorphic surfaces in SE Qld streams have a geomorphic life-cycle (e.g. self-limiting vertical accretion, downstream progradation, episodic destruction). Vegetation on these surfaces will serve to modify those life-cycles (e.g. accretion rates on surfaces will decline as they aggrade). The goal of this project is to develop strong theory that can be tested by empirical evidence. A challenge of the project is to clarify the total fine-sediment budget for the river system, and identify the influence of riparian vegetation on that budget. The outcome will be a capacity to predict the effectiveness of specific riparian revegetation on specific parts of the river system (benches, banks) for sediment management. This can be expressed as a 'trap-efficiency' for surfaces with and without vegetation. Possible specific tasks for the project 1. Identify the specific periods of time, and flow regimes, that provide the sediment and nutrient pollution that it of most concern to water managers (in order to target management) 2. Review the literature and understanding of the distribution and life-cycles of geomorphic sedimentary units in SE Qld streams (there are multiple benches and surfaces in the channel). 3. Develop a conceptual model of sediment flux through geomorphic units over time, with and without specific riparian vegetation. This requires basic information about suspended sediment transport during events of different recurrence interval so that we can establish relationships between stage and suspended sediment concentration. 4. From the conceptual model develop specific hypotheses that can be tested. For example, the model might predict that densely vegetated surfaces will have twice the deposition rate of unvegetated surfaces, but that the rate of deposition on surfaces will decline as a power function of depth. Such theoretical propositions would guide the field sampling. 5. Establish the best hierarchy of field methods that can identify sediment budgets, including: a. Identify river reaches that have repeat LiDAR data in order to establish a first-cut storage volume from DEMs for recent flood events (this is also a good way to relate

storage to riparian vegetation as the LiDAR also provides good data on vegetation characteristics, and veg change). b. Field measurement of deposition rates on characteristic surfaces with characteristic riparian vegetation using a variety of methods (including optically stimulated luminescence (OSL) dating, caesium-137 (137Cs) dating, heavy metal analysis, flood bed interpretation, and dendrochronology. c. Date decade-to-century sedimentation rates using optically stimulated luminescence dating of sediment on different geomorphic surfaces. d. Consider real-time 'snapshot' turbidity sampling to more closely identify the flux of sediment (losses and gains downstream) by following a flood wave down the catchment (this involves sampling through a series of hydrographs across a full catchment) (see Grayson et al. 1996). Sampling above and below reaches with specific characteristics allows many hypotheses to be tested. This is a risky, but very promising field approach. It would remove some of the speculation about sediment losses. It requires a coordinated campaign approach, and being able to respond to a large event at short notice. Research Environment The student will be based in the School of Geography (Faculty of Science) at The University of Melbourne (UoM), but they will also be spending time at the Australian Rivers Institute (ARI) at Griffith University in Brisbane. Both institutions have large river based research programs. At Geography at UoM there is research into fluvial geomorphology, river management, and environmental reconstruction, but there is also close collaboration with the Department of Infrastructure Engineering that studies river engineering, hydrology, and environmental flows. You will join a lively team of post-graduate students working on related projects. The ARI is Australia's largest university aquatic ecosystem research group with globally recognised expertise in river, catchment and coastal ecosystems and the interaction with these systems in society. It brings together 130 staff and post-graduate students at the Nathan and Gold Coast campuses. Our research focuses on a "source to sea" processes.

PhD Topic 3 The effectiveness of management activities aimed at accelerating recovery of stream systems affected by slugs of sand Field location: The Glenelg River, western Victoria, SE Australia. Sponsor: Glenelg Hopkins Catchment Management Authority (GHCMA). Skills required: It would be advantageous to have the following skills (or a strong interest in developing them): fluvial geomorphology, river engineering, sustained field work, hydraulics, sediment transport, basic ARC-GIS skills, and capacity to communicate with landholders. We would encourage students with excellent skills in one or more of the following areas to apply: fluvial geomorphology, river engineering, geography, environmental science. Supervision: Supervisor would be Assoc. Professor Ian Rutherfurd (School of Geography, Faculty of Science, the University of Melbourne). A full supervision panel of experts would be appointed in discussion with the student. Support: The applicant will apply for a post-graduate scholarship through the science faculty of the University of Melbourne. Depending on the quality of the applicant, and if they are successful in winning a scholarship (scholarship success rate for eligible candidates in 2014 was around 40%) they could receive a cash top-up to their stipend. The student will also receive a lap-top computer, and funding support to attend conferences during their candidature. All costs of the project are covered by support from the sponsor. Project description Rivers around the world have been degraded by large loads of sand delivered to the stream by mining and gullying. These 'sand slugs' typically migrate through river systems over decades and centuries. They fill river pools and destroy, and homogenise morphological diversity. This PhD project will investigate how effective various management actions have been in accelerating the recovery of streams degraded by sand. The focus of this project is the Glenelg River system in western Victoria, in SE Australia. The project is supported with funding from the Glenelg Hopkins Catchment Management Authority (GHCMA). The GHCMA won the 2013 Australian River Prize for its catchment scale river restoration program on the Glenelg River. An important part of that program has been attempting to protect high-value sections of the river from the huge volumes of sand delivered to the river by catchment gullying in the first half of the 20th Century. Actions include commercial sand extraction, placing logs in the river bed to trap sand, excluding cattle from the river, and fencing and revegetating sediment sources.

This PhD project will use (and improve) existing models of sand-slug dynamics in order to predict how sand will move through the river, and through river-pools, over decades. Of particular interest is the impact of various management actions on the dynamics of the sand-slugs. The research will involve developing conceptual models of sand-slug change that can be tested with surveyed data, and with field measurement. Existing research, multiple river surveys, LIDAR surveys of the full river, and excellent field data (including hydrology), makes this catchment one of the best places in the world to study sand slugs dynamics. The goal of the research is to improve geomorphic theory, but also to identify the most effective actions in managing sand slugs. Research Environment The University of Melbourne has an active program in river and water related research. This spans from fluvial geomorphology, river management, and environmental reconstruction, in the School of Geography, to river engineering, hydrology, and environmental flows in the Department of Infrastructure Engineering. You will join a lively team of post-graduate students working on related projects.