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Big Flood Newsletter Issue 5, June 2015
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Issue 5: June, 2015
 
Welcome to our June Edition of the ‘Big Flood’ Newsletter and judging by the content here, it looks like everyone is busy and productive across all stages of the Project.

In late April I was invited by the Department of Science, Information Technology and Innovation (DSITI) to represent the project at a meeting and discussion forum with the Academy of Science President Prof. Andrew Holmes. He was very impressed with the nature and scope of the work being undertaken and encouraged us to communicate these results as widely as possible so the Academy is also aware of their existence.

I have also recently returned from a trip to Europe where I was invited to attend the Special Meeting of the Royal Geographical Society and the British Society for Geomorphology on ‘Stormy Geomorphology’ in London. I presented a compilation of research results that outlined the data and interpretations to date on the nature and timing of flood events in south east Queensland (SEQ) and the relevance for landscape resilience. I also launched and distributed the MEGAFACTS (see bottom of the newsletter) that Ramona Dalla Pozza has been working on over the past few months and they received very positive feedback. Overall the meeting was an excellent event and there is no doubt that we are making a significant contribution in this area. As part of this,  I submitted a paper for the Special Issue of Earth Surface Processes and Landforms entitled ‘Defining the floodplain in hydrologically-variable settings: implications for flood magnitude:frequency and landscape resilience’. The paper explores how traditional notions of delineating floodplains based on flood recurrence intervals that range between 1-2.5 years are not appropriate or helpful in settings such as SEQ. For example a review of 40 representative gauging stations throughout the region undertaken by James Daley confirmed that the range of bank top flows extends from 1- 200 years (Figure 1) with a dominant mode >50 ARI. This paper is currently in review with the journal.

As part of the trip I also visited and presented a seminar at Wageningen University in the Netherlands at the invitation of Dr Arnaud Temme and Dr Jerry Marouils. As Wout Pulles is about to depart (see report at end of this edition), we will soon host another 5 students from Wageningen to undertake work across a range of topics both on the Lockyer and elsewhere. I also presented to the Natural Hazards Group at Trinity College. Many parts of both Ireland and the UK experienced severe floods and coastal storms over the period 2011-2013 so it is very interesting to share data and exchange techniques from a range of geomorphic settings. 
 
Figure 1. Distribution and cumulative frequency of banktop flows in 40 representative gauging stations in SEQ. (from Croke et al., in review ESPL).

Stage Leader Updates

Stage 1 – Update

 
Lead CI - Jacky Croke
PhD Students - James Daley and Daryl Lam

Work underway in Stage 1 continues to progress by way of James Daley’s and Daryl Lam's work which is now evolving to produce some very interesting results which are currently being worked up into publications. Annegret Larsen has also completed the stratigraphic and sedimentological interpretation of the deep cores from the Lower Lockyer and we are eagerly awaiting the return of some OSL dates from channel units by Ashneel Sharma in mid-June. The sediment from these cores has also been investigated for pollen with collaboration from A/Prof Patrick Moss at UQ and again, evidence points strongly to the existence of a slow moving, backwater environment prevalent throughout the lower Lockyer during this phase of valley and channel evolution. The data will undoubtedly make a major contribution to our understanding of why the Lockyer behaves in its current form of adjustment which will extend Chris Thompson’s paper recently submitted to Catena on an appropriate channel evolution model for the lower Lockyer over the more recent timescale. Two of the student’s from Wageningen University will be examining in detail the river adjustment dynamics and sediment storage characteristics at the junction between the Lower Lockyer and the mid-Brisbane as we believe this is a key site in understanding the sediment delivery dynamics of the whole system.

Stage 2 – Update

 
Lead CI - Jon Olley
PhD Students  - Heather Haines and Jack Coates-Marnane

During the past quarter the work undertaken in Stage 2 has primarily focussed on completing two publications and progressing Heather and Jacks PhD's.  Jack has completed new fieldwork collecting samples for comparison with his marine records. He also successfully completed his mid-candidature review.  Heather and Jon have completed and submitted a literature review paper to Quaternary Science Reviews on dendroclimatology in Australia.  Comments were received back from the journal on “River response to European settlement in the subtropics. Agriculture, floods and channel change in a subtropical catchment: the Brisbane River” these have been addressed and the paper returned to the journal Athropocene.

Stage 3 – Update

 
Lead CI - Kirstie Fryirs
PhD candidate – Peyton Lisenby (MQ)
 
Stage 3 is currently in an intense data collection and analysis phase. This work now revolves largely around the PhD work of Peyton Lisenby which is reported on elsewhere in this newsletter. The paper on post-European river change along the Lockyer trunk stream (reported in last newsletter; Fryirs et al.) has been published in the journal Geomorphology. The paper on patterns of erosion and deposition and the nature of (dis)connectivity along the Lockyer trunk stream that occurred during the 2011 flood (reported on in last newsletter; Thompson et al.) has been accepted and will appear in the journal River Research and Applications.

Stage 4 – Update

 
Lead CI - Chris Thompson
 
Over the last couple of months, Chris Thompson and Ramona Dalla Pozza have been engaging with Queensland Government Agencies and the Council of Mayors SEQ to provide ARC Big Flood research findings. This work is contributing to the Lockyer Creek Catchment Action Plan and the Queensland Government’s ‘WetlandInfo’ website.

Chris has also been working with Wout Pulles, a student from Wageningen University who has come over to complete a 4 month internship. Wout has been investigating bank sediment properties in the Lockyer (see later in the newsletter).
 
Chris also attended the Floodplain Management Association’s National Conference in Brisbane, 19-22 May. The conference attracted over 350 practitioners involved in floodplain risk management. Attendees included Commonwealth, State and Local Government elected representatives and staff, researchers, consultants, engineers, land-use planners and emergency response personnel. Chris delivered an oral presentation called “Understanding the Geomorphic System for Floodplain Hazard Awareness, Lessons from the Lockyer”.

Below is an anstract from the recently submitted paper to CATENA journal for publication is Thompson, Croke, Fryirs & Grove (In review). A channel evolution model for non-incising, macrochannel systems.

Abstract: A channel evolution model (CEM) represents stages of channel development in response to specific types of disturbance. In recent years, classic incised/disturbed CEMs have provided process-based understanding of channel adjustment and formed the cornerstone for river restoration and rehabilitation. While broadly applicable to alluvial systems in temperate and semi-arid regions, these models cannot be assumed to be universally applicable. Lockyer Creek has a notable macrochannel morphology and is subject to high hydrological variability typical of many subtropical climates. The aim of this paper is to present a case study of channel adjustment and evolution in lower Lockyer Creek, to determine if existing CEMs adequately describe processes of channel adjustment and the associated trajectories of change typical of river systems in subtropical settings. Lockyer Creek has recently been subjected to a spate of flooding resulting in significant channel erosion and offers an ideal opportunity to investigate the nature and rate of channel adjustment processes, Specifically, we address the following questions: (1) Do the classic incised/disturbed CEMs adequately represent the observed macrochannel adjustment? and (2) If not, then what is the channel evolution model for these systems, of which lower Lockyer Creek is an example? Results show that these are non-incising systems where wetflow bank mass failures are the dominant process of channel adjustment.  They occur within the channel bank top boundary resulting in no change to overall bank-top width. Furthermore, subsequent floods deposit sediment in the failure scars and failure headwalls generally do not retreat beyond channel bank-top. Channel adjustment has not followed the evolutionary stages for incised/disturbed channels and a new four stage macrochannel CEM is proposed for these subtropical systems. The proposed CEM illustrates a cyclical pattern of erosion by channel bank wetflow mass failures followed by re-aggradation by deposition and oblique processes contributing to bank rebuilding. This CEM provides the relevant information required to determine the stage of macrochannel adjustment and whether intervention is required or will be successful.   

PhD Updates 

Daryl Lam - PhD Update

 
 
One of the key objectives for the last quarter to was head out into the Mary catchment and look for more evidence of extreme slackwater deposits (SWDs). A reach just upstream of Fisherman’s Pocket yielded good results. A tributary junction SWDs setting was deemed ideal based on geomorphic setting and this is further complemented by evidences of stage-height indicators from the flood that came through in February 2015 (see Figure 1). Onsite stage-heights are useful for calibration of other flood heights (e.g. SWDs’) with the nearest gauging stations. Preliminary fieldwork has been completed and a follow-up fieldwork will be undertaken in the next quarter.
 
Daryl is also working on going beyond the initial plan of deriving regional Hydrological Envelope Curves (ECs) for Australia, and assigned probabilistic interpretation to the ECs. This will help to address the main criticism of ECs, which relates to their deterministic nature. This can help complement the regional flood frequency analysis (RFFA) that is traditional used in Australia to understand return intervals of floods.
 
The next quarter will hopefully see Dayl complete more fieldwork done in Logan-Albert, Upper Brisbane and South Coast Basin. These are pending approvals and documentation of access from the respective landowners and/or authorities. 
Figure 1: Stage-height indicators: silt-line left on trees along tributary, left by backflooding of the main Mary River.

Peyton Lisenby - PhD update

 
Recently, PhD-level research in Stage 3 has focused on analysing the channel behaviour of the three largest tributary channels of Lockyer Creek – Buaraba, Laidley, and Tenthill-Blackfellows Creeks. Forms, distributions, and ranges of geomorphic adjustment were determined through comparisons of sequential historical aerial imagery and maps. Individual forms of adjustment were characterized by the basin- and channel-scale morphometric and hydraulic conditions (stream power, channel width, valley width, channel depth, slope, river type and bed texture, basin area) at the location of adjustment. Statistical comparisons were then made between tributary catchments and forms of adjustment according to physical condition data. Results demonstrate distinct behavioural differences between Tenthill-Blackfellows, Buaraba and Laidley Creeks in terms of both distribution and physical condition of adjustment. These distinctions are utilized to establish a relationship between expectations of channel adjustment and the basin- and channel-scale conditions controlling or influencing these adjustments. Further Stage 3 research will continue in its analysis of geomorphic work and adjustment by considering the significance and effectiveness of adjustments, flood events, and flow frequency in the Lockyer Valley.
 

Heather Haines – PhD Update


Work on the dendrochronology component of Stage 2 is moving forward at pace with results beginning to come together for the Lamington National Park chronology being developed from this thesis.  Several of the trees from this site have been compiled into tree master files where the pattern of wide and narrow rings has been matched between the cores from a single tree.  An example of this can be seen in Figure 1 where the four cores from Tree LLB01 have been developed into a master file from 1897 to 2012 that demonstrates wide rings in 2001, 1986, 1968, 1956, and 1951 and narrow rings in 2003, 1979, 1965, 1940, and 1926.  The upslope core A has four locally absent rings (indicated by the white ovals) which means that while these rings are seen in the other three cores they are missing in this core.  This is a common feature in the upslope samples in my study sites and represents why it is important to take replicate cores from different portions of all study trees.  The next step is to compile the tree masters into a site master chronology.  This will be done by using traditional tree-ring measurement techniques and also by incorporating data from ITRAX and Radiocarbon analysis undertaken at ANSTO through my AINSE Postgraduate Research Award.  I have spent four weeks at AINSE over the last two months running these analyses with results expected to arrive by the end of June.  The preliminary results from this chronology will be presented at INQUA in late July of this year. 
 
Along with the work directly on the Lamington chronology I have had several other successes over the past three months.  My literature review paper has been submitted to Quaternary Science Reviews and is currently undergoing review.  I have begun detailed analysis on the rainfall data for SEQ to determine exactly where the differences in rainfall patterns occur across this region.  This analysis will form the basis for the next paper to be published in regards to my PhD.  I have also been awarded another Wet Tropics Management Authority (WTMA) Student Research Grant in collaboration with Dr Nathan English from JCU, Townsville.  Following on the success of our 2014 WTMA Grant Nathan and I would like to explore if differences in growth being observed at his tropical Blue Kauri Pine site and my subtropical Hoop Pine site are due to the difference in species or environment.  As such the WTMA has awarded us a 2015 grant for $2,500 to conduct fieldwork to core a site of Hoop Pine trees in the tropics.  The goal of this new grant is to develop a rainfall reconstruction for tropical Hoop Pine that can be compared to my Lamington chronology to understand if this species is useful for climate reconstructions across the state.
 
Over the following quarter I will be working on the Lamington chronology and the rainfall analysis paper, completing my mid-candidature milestone, attending a dendrochronology training program in Maine in early June and presenting at INQUA in Japan.
Figure 1: The four cores (A, B, C, D) taken from Tree LLB01 and matched into a tree master file.  Locally absent rings are indicated with white ovals.

This is an excerpt from a journal article which has been submitted for review. As such all copyright is reserved. If you require further details about this material, or wish to reference it, please contact the authors directly for full details.

The nature and timing of formation macrochannel in the Lockyer Creek


Daley, J. 
 
This paper is primarily focused on the mid-reaches of the Lockyer Creek between Lockyer Sidings and Grantham, in an attempt to understand the significant downstream variation in channel capacity. The reach varies longitudinally between channels that can contain all flood events (up to probable maximum flood) and a channel capacity with a bank-full recurrence <20 years (Croke et al. 2013). The crux of this paper is to understand when and why the channel has evolved in this way. One of the key findings is the formation of the macrochannel approximately 10 000 years ago, with ubiquitous terrace abandonment at that time. Radiocarbon dating of soils on the lower Lockyer and Tenthill Creek by Powell (1987) indicate similar age of incision, suggesting a system-wide incisional event at the Pleistocene-Holocene boundary.

The next component of this work will be to compare this with known climate proxies during the late Pleistocene and early Holocene to determine the cause of channel incision and river response in the subtropics, where streams have characteristically high flow variability. A simple exercise of plotting inundation frequency on gauging cross-sections highlights the large channel capacity of rivers throughout the region. These channels have a significantly higher discharge capacity than the conventionally-assumed annual mean flood, profoundly affecting channel processes. Previous research has shown comparative macrochannel morphology throughout the region and terrace formation in the Pine Rivers, Logan River and Kedron Brook systems (Beckmann and Stevens 1978), correlated by height above channel and associated soils. However, as yet there is no dating control on these systems to determine whether they have formed by local (stream power, bank resistance) or regional factors (climate).
Profiling the terrace bank of the mid-Lockyer Creek on a recent fieldwork expedition. Despite the steep, exposed face of this bank, it is highly stable and resistant to erosion. Horizontal beds of fine-grained muds can be traced along the profile in this photo, providing an indication of their formation prior to stream incision.
Flood recurrence intervals for selected SEQ streams, with the broken line reflecting the highest recorded flood
 



This is an excerpt from a journal article which has been submitted for review. As such all copyright is reserved. If you require further details about this material, or wish to reference it, please contact the authors directly for full details.
 

What can colour tell you about flooding and past disturbances in Moreton Bay?


Coates-Marnane, J. 
 

Pigments and phytoplankton 

Marine algae and bacteria capture energy from the sun via photosynthesis. Light energy from the sun is absorbed by pigments within the cells of these organisms and transformed to energy in the form of sugar. Pigments are organic molecules and depending on their structure will absorb different wavelengths of light. Chlorophylls are the most common type of pigment found in algae, bacteria and plants and typically have a deep emerald green appearance in concentrated forms. This is because it is absorbing most light in the red-orange and blue-purple wavelengths and what we see is reflected green light. The wave lengths that the pigment absorbs the most are referred to as the absorbance maxima. The two other main groups of pigments are xanthophylls and carotenes. There are over 30 different types within these three broad groups of pigments that have been identified (Jeffrey et al., 1997). Different algae, marine plants and bacteria contain varying amounts and types of pigments. Often pigments are specific to different groups of these organisms. For example zeaxanthin, a type of carotene, typically only occurs in cyanobacteria. Based on these differences pigment concentrations in water samples and marine sediments can be used as biomarkers that can indicate the relative abundance of different groups of photosynthetic organisms that are present (Jeffrey et al., 1997). Often this work is combined with remote sensing techniques to map ocean wide algal blooms and marine productivity.
 

Moreton Bay 

The photosynthetic community of Moreton bay has been shown to respond dynamically to the variability in discharge of major rivers entering the basin (Saeck et al., 2012).  Based on this body of previous research we are aiming to develop a record of environmental disturbances in Moreton Bay based variations in the quantity and type of pigments preserved in bottom sediments of the bay. We are specifically interested in developing a biomarker for flooding events in order to develop a long-term ~1000 year record of flood frequency for SEQ.  Records of environmental change in estuarine based on pigments have been successful in environments similar to Moreton Bay.

As the remains of algae, bacteria and plant matter accumulate on the seafloor so do the pigments associated with each group. Over time, these become buried by further sedimentation and are preserved under anoxic conditions. By coring these sediments and extracting and measuring the pigments a record of how the photosynthetic community has been changing over the past millennia can be developed (Figure below). This project is being led by Dr Joanne Burton (DSITI) and I am collaborating as a PhD student.

Methods 

The identification and quantification of fossilized pigments in sediment cores is being performed in the Chemistry Centre (DSITI).  I am currently working in collaboration with Fred Oudyn (DSITI) on the development of methods for this analysis. The analysis is being performed using ultra high pressure liquid chromatography coupled with a mass spectrometer (UHPLC-MS).  Pigments are being identified by their peak absorbance maxima (UHPLC) and mass to charge ratio (MS). The concentration of pigments is being calculated by comparing their responses in samples to certified analytical standards (Figure below). As pigments are sensitive to light and are present in our samples at very low levels extensive method development and fine tuning of the instruments has been required.
This lab work is being co-ordinated in addition to further field observations in Moreton Bay. Recently I joined Jacob Gruythuysen a principal technical officer of the estuarine Ecosystem Health Monitoring Program (EHMP) on a trip to Moreton Bay to collect more bottom sediment samples and observe the water conditions following the extreme rainfall event of 1/5/2015 that caused significant flooding through SEQ (Figure below). This work will complement and previous work by Sarah Pausina (Griffith) on quantifying down-core concentrations of biogenic silica in marine cores; a proxy for total primary production of Moreton Bay. Also this will be complementary to ongoing work by John Tibby (UA) on diatom work with sediment cores.
 
 
References
Jeffrey, S.W. Mantoura, R.F.C. Wright, S.W (Ed.) 1997. Phytoplankton pigments in oceanography: guidelines to modern methods. Monographs on Oceanographic methodology, 10 UNESCO Publishing: Paris ISBN 92-3-103275-5 661pp.
Saeck, E.A., O’Brien, K. R., Hadwen, W., Rissik, D., & Burford, M. A. 2013 Flow events drive patterns of phytoplankton growth along a river-estuary continuum. Marine and Freshwater Research. 64(7): 655-670.

International students join the team.... meet Wout Pulles


Wout Pulles is an International Land and Water Management student from Wageningen University in the Netherlands. Wout has spent the last four months doing an internship at the University of Queensland as the final part of his degree. Wout investigated the differences in erosion sensitivity of bank in the Lockyer valley by comparing the grain size distributions of three different sites. The sediment samples were analysed using the Mastersizer 2000 facilities in the Chemistry Centre, DSITI. Erosion sensitivity is highly dependent on the percentage of clay and silt in the soil relative to the amount of sand and gravel. Comparison of the terrace sites and the levee sites revealed significant differences in the composition. Clay and silt proportions were much higher in the terrace sediments than in the levee sediments. These differences can be related to the differences in the erosion rates as the levee sites have a higher erosion rates than the terraces sites.
Wout Pulles on a fieldtrip to the mid-Lockyer creek to analysis the composition of fine-grained sediments in the terrace banks.
To communicate the key messages from the Big Flood research to policy and decision-makers we have just released six MEGAFACTS see links below:
  1. LiDAR helping to keep soil on the paddock
  2. Macrochannels = Flood risk
  3. Where does sediment go in floods?
  4. Artificial levees: friend or foe?
  5. What causes river bank mass failures?
  6. What is Stream Power?
Please feel free to distribute widely.

Publications 


Baggs Sargood, M. 2013. Hitting rock bottom: Morphological response of upland bedrock-confined streams to catastrophic flooding, BEnvSc Hons, School of Earth & Environmental Science, University of Wollongong.

Baggs-Sargood, M., Cohen, T.J., Thompson, C.J., Croke, J. 2015. Hitting rock bottom: morphological responses of bedrock-confined streams to a catastrophic flood, Earth Surface Dynamics 3, 1-15, 2015. DOI 10.5194/esurf-3-1-2015.

Croke, J., Fryirs, K., Thompson, C. 2013. Channel-floodplain connectivity during an extreme flood event: Implications for sediment erosion, deposition, and delivery, Earth Surface Processes and Landforms 38 (12): 1444-1456.

Croke, J., Reinfelds, I., Thompson, C., Roper, E. 2013. Macrochannels and their significance for flood-risk minimisation: examples from southeast Queensland and New South Wales, Australia, Stochastic Environmental Research and Risk Assessment: 1-14.

Croke, J., Todd, P., Thompson, C., Watson, F., Denham, R. Khanal, G. 2013. The use of multi temporal LiDAR to assess basin-scale erosion and deposition following the catastrophic January 2011 Lockyer flood, SE Queensland, Australia, Geomorphology 184: 111-126.

Croke, J., Denham, R., Thompson, C., and Grove, J. 2014 Evidence for self-organised criticality (SOC) in river bank mass failures; a matter of perspective? Earth Surface Processes and Landforms. DOI: 10.1002/esp.3688 

Fryirs, K., Lisenby, P. and Croke, J. 2015. Geomorphic responses to a catastrophic flood in a resilient river system: Historical context for the 2011 Lockyer Valley floods. Geomorphology.241, 55-71. doi:10.1016/j.geomorph.2015.04.008

Fryirs, K., Lisenby, P., and Croke, J. 2015. Morphological and historical resilience to a catastrophic flood in the Lockyer Valley, SEQ Australia. Geomorphology, 241, 55-71.
Grove, J., Croke, J. and Thompson, C. 2013. Quantifying different riverbank erosion processes during an extreme flood event, Earth Surface Processes and Landforms 38 (12): 1393-1406.

Grove J.R., Croke J., Thompson C.J. 2014. Making a difference: examples of the use of repeat LiDAR datasets to guide river management decisions following extreme floods, in Vietz, G; Rutherfurd, I.D, and Hughes, R. (editors), Proceedings of the 7th Australian Stream Management Conference, Townsville, Queensland, pp 109-115. 

Smith, B. 2013. The role of vegetation in catastrophic floods: A spatial analysis, BEnvSc Hons, School of Earth & Environmental Science, University of Wollongong.

Thompson, C., and Croke, J. 2013. Geomorphic effects, flood power, and channel competence of a catastrophic flood in confined and unconfined reaches of the upper Lockyer valley, southeast Queensland, Australia, Geomorphology 197: 156-169.

Thompson, C., Croke, J., Grove, J., Khanal, G. 2013. Spatio-temporal changes in river bank mass failures in the Lockyer Valley, Queensland, Australia, Geomorphology 191: 129-141.

Thompson C., Croke, J., Dent, C. 2014. Potential impacts of levee construction in the Lockyer Valley, in Vietz, G; Rutherfurd, I.D, and Hughes, R. (editors), Proceedings of the 7th Australian Stream Management Conference, Townsville, Queensland, pp 109-115. 

Thompson, C., Fryirs, K., and Croke, J. 2015. The disconnected conveyor belt: Patterns of longitudinal and lateral erosion and deposition during a catastrophic flood in the Lockyer Valley, southeast Queensland, Australia. River Research and Application, DOI: 10.1002/rra.2897.
 

Submitted


Croke, J., Thompson, C., Daley, J., Fryirs, K., Lisenby, P., Lam, D., Dalla Pozza, R., Grove, J. and Cohen, T. (in review). Defining the floodplain in hydrologically-variable settings: Implications for flood magnitude-frequency analysis and interpretations of landscape resilience. Earth Surface Processes and Landforms Special Issue.

Kemp, J., Olley, J., Ellison, T., McMahon, J.  Submitted. Agriculture, floods and channel change in a subtropical catchment: the Brisbane River, Australia.  Anthropocene.      

Haines, H.A., and Olley, J.M. Submitted.  A review of dendroclimatology in Australia.  Quaternary Science Reviews.
 
Thompson, C. J., Croke, J., Fryirs, K., and Grove, J. (in review). A channel evolution model for non-incising, macrochannel systems. Catena.


Conference papers

Thompson, C.J. 2015. Understanding the geomorphic system for floodplain hazard awareness, lessons from the Lockyer. Floodplain Management Association National Conference, 19-22 May 2015, Brisbane.

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Our mailing address is:
ramona.dallapozza@dsitia.qld.gov.au
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