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Flow resistance through riparian forests due to drag on trees is often expressed in hydraulic models with an increase in a boundary resistance factor such as Manning's n. However, when Manning's n is used as a proxy for vegetation drag, this parameter is dependent on flow conditions and a single, uniform value may be inadequate for simulating a broad range of flood magnitudes. To investigate this issue, flow resistance, and the commensurate Manning's n values through a riparian forest were computed using measured drag forces and estimates of the forest structure and tree morphology. The computed Manning's n values were applied to a 2D hydraulic model (TUFLOW) to simulate an observed flood and a range of design floods. Modelled peak flood levels for the observed flood were 0.16 m lower on average than that recorded at debris marks. There was little difference in modelled flood levels when using the computed Manning's n compared to a traditional, uniform Manning's n. Reassuringly, the traditional method appears adequate when reliable calibration data is available. Otherwise, the method developed here provides a useful alternative in cases where calibration data is limited or for testing reforestation as a nature‐based solution in river or flood management. [ABSTRACT FROM AUTHOR]

Buildings and monuments constructed from stone provide some of the best‐preserved surface archaeology, but their construction ages can be difficult to determine using radiocarbon techniques. In Australia, stone arrangements are recognised as architectural or symbolic features belonging to Aboriginal societies. The structures are predominantly inorganic with shallow infill, hampering attempts to determine their antiquity. Optically stimulated luminescence (OSL) techniques have the potential to date these features, but their complex geometry requires careful consideration of the background radiation. Here, we present the first ages for Australian Aboriginal stone construction using single‐grain OSL techniques on quartz from stone arrangements in central Australia. Beta and gamma dose rates and the cosmic ray dose have been estimated from mapping the gross geometry of stone and sand courses. The resulting OSL ages are internally consistent and, together with fallout radionuclides 137Cs and 210Pb, indicate a minimum age for construction between 1959 and 1981 AD. We demonstrate that single‐grain OSL techniques can be used to determine the age of emplaced sand between stones and, assuming a stable substrate, can be used to date stone building construction as well as building occupation, providing chronologies for sites where organic material for radiocarbon analysis is limited or unavailable. [ABSTRACT FROM AUTHOR]

Kiacatoo Man, a large, rugged Aboriginal adult buried in the Lachlan riverine plains of southeastern Australia, was discovered in 2011. Laser‐ablation uranium series analysis on bone yielded a minimum age for the burial of 27.4 ± 0.4 ka (2σ). Single‐grain, optically stimulated luminescence ages on quartz sediment in which the grave had been dug gave a weighted mean age of 26.4 ± 1.5 ka (1σ). Luminescence samples from the grave infill and from sediment beneath the grave exhibit overdispersed dose distributions consistent with bioturbation or other disturbance, which has obscured the burial signal. The overlap between the minimum (U‐series) and maximum (luminescence) ages places the burial between 27.0 and 29.4 ka (2σ). Luminescence ages obtained from the channel belt of between 28 ± 2 and 25 ± 3 ka indicate that fluvial sedimentation was occurring before the Last Glacial Maximum, which is consistent with the broader geomorphic setting. Together, these results are internally and regionally consistent, and indicate that Kiacatoo Man was one of the more ancient individuals so far identified in Australia. His remains are important to our understanding of patterns of biological variation and other processes that have shaped people in the Murray‐Darling Basin through time. Copyright © 2019 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The identification of the sources of sediment is a key part of the management of waterways. This is typically achieved through the well‐established technique known as sediment source fingerprinting that uses tracers and statistical mixing models. Until recently, the approach for solving these mixing models has been dominated by frequentist methods. This review focuses on the growing interest in Bayesian methods for sediment fingerprinting and presents them as an alternative or complementary addition to the frequentist methods. Bayesian methods emphasize flexibility, for example, in the choice of probability distributions for tracers, inclusion of parameter probability terms, the choice of how to characterize tracer proportion, and the choice of fully or empirical Bayesian techniques. The Bayesian approach flexibly combines previous known and current information, to produce results that aim to accurately reflect the real‐world environment. Under the Bayesian paradigm, all model parameters are treated as random variables, and this allows all sources of variation to be explicitly communicated and modelled. Although there are considerable advantages to using a Bayesian approach for sediment tracing, there are some possible problems the practitioner should be aware of. These include computational issues and potential difficulties in choosing probability distributions to realistically represent model parameters. Though there are choices as to what Bayesian approach to implement (i.e., fully or empirical Bayesian), a fully Bayesian approach has been found to best retain fidelity to the Bayesian paradigm of treating all parameters as random variables. It has been recognized that the field of sediment source fingerprinting would greatly benefit from the development of a model that incorporates the tracer selection process into the modelling framework allowing for an all‐in‐one approach, and the flexibility of a Bayesian approach makes this development possible. [ABSTRACT FROM AUTHOR]

Abstract: Concentrations of major and trace elements in freshwater fauna are often a reflection of local sediment chemistry. Biogeochemical profiles of freshwater species can be used to provide accurate and affordable assessments of species distribution, movement, and connectivity within river systems. Incorporating additional elements could significantly increase the precision and accuracy of population discrimination and movement analyses. To increase the variety of elements in biogeochemical tracing studies, we compared the concentrations of 38 major, trace, and rare earth elements (REEs) in bulk sediment (< 10 μm) and atyid shrimp from three rivers in South East Queensland, Australia. We determined which elements were correlated between sediment and shrimp samples and if these elements could distinguish different sample populations. This process identified elements that can directly associate shrimp with local sediment geochemical profiles. We found potassium (K), aluminum (Al), yttrium (Y), and the REEs cerium (Ce), lanthanum (La), and samarium (Sm) were spatially correlated between shrimp and sediment samples. Concentration ratios indicated K may be a relatively conservative tracer. Aluminum, REEs, and Y may undergo characteristic fractionation between sediment and shrimp tissue. Multivariate analysis indicated these elements could distinguish shrimp populations between sample sites. Results suggest that this small number of elements can link shrimp with specific rivers in accordance with local geochemistry, and thus may be valuable tracers with which to distinguish freshwater populations. As we measured bulk sediment concentrations, sampling these tracers is a relatively simplistic process that could be applied in a range of field conditions. [ABSTRACT FROM AUTHOR]

Hydrologic variability is a fundamental driver of ecological processes and species distribution patterns within river systems, yet the paucity of gauges in many catchments means that streamflow data are often unavailable for ecological survey sites. Filling this data gap is an important challenge in hydroecological research. To address this gap, we first test the ability to spatially extrapolate hydrologic metrics calculated from gauged streamflow data to ungauged sites as a function of stream distance and catchment area. Second, we examine the ability of statistical models to predict flow regime metrics based on climate and catchment physiographic variables. Our assessment focused on Australia's largest catchment, the Murray-Darling Basin (MDB). We found that hydrologic metrics were predictable only between sites within ~25 km of one another. Beyond this, correlations between sites declined quickly. We found less than 40% of fish survey sites from a recent basin-wide monitoring program (n5777 sites) to fall within this 25 km range, thereby greatly limiting the ability to utilize gauge data for direct spatial transposition of hydrologic metrics to biological survey sites. In contrast, statistical model-based transposition proved effective in predicting ecologically relevant aspects of the flow regime (including metrics describing central tendency, high- and low-flows intermittency, seasonality, and variability) across the entire gauge network (median R² ~ 0.54, range 0.39-0.94). Modeled hydrologic metrics thus offer a useful alternative to empirical data when examining biological survey data from ungauged sites. More widespread use of these statistical tools and modeled metrics could expand our understanding of flow-ecology relationships. [ABSTRACT FROM AUTHOR]

Sediment tracing using geochemical properties is an efficient way to identify the spatial sources of transported sediments delivered to waterways. Here, the contribution of soil sources to river bed sediments has been quantified in Emu Creek, a headwater catchment in south eastern Queensland, Australia. Soil samples were collected from the eight major rock types present in the catchment and were related to river bed sediments collected from eight sites along the main channel. Geochemistry, as characterized by 39 elemental concentrations, was measured using inductively coupled plasma mass spectrometry and inductively coupled plasma optical emission spectrometry. Three particle size fractions were examined, <10, 10-63 and 63-212 µm, with the three resultant mixing models showing divergent results. We conclude that the results of sediment mixing models based on the analysis of one grain size should not be assumed to apply across the entire particle size range of transported sediment, emphasizing the need to match the size fraction used in tracing studies to that size fraction of interest in downstream sinks. Furthermore, we present results highlighting the control transport distance plays in source dominance, with this particularly evident in the coarser fraction, where local sources dominate over more distant sources. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

No abstract is available for this article. © 2021 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

No abstract is available for this article. © 2021 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A decline in the ecosystem health of Australia's Moreton Bay, a Ramsar wetland of international significance, has been attributed to sediments and nutrients derived from catchment sources. To address this decline the regional management plan has set the target of reducing the loads by 50%. Reforestation of the channel network has been proposed as the means to achieve this reduction, but the extent of revegetation required is uncertain. Here we test the hypothesis that sediment and nutrient loads from catchments decrease proportionally with the increasing proportion of the stream length draining remnant vegetation. As part of a routine regional water quality monitoring program sediment and nutrient loads were measured in 186 flow events across 22 sub-catchments with different proportions of remnant woodland. Using multiple linear regression analysis we develop a predictive model for pollutant loads. Of the attributes examined a combination of runoff and the proportion of the stream length draining remnant vegetation was the best predictor. The sediment yield per unit area from a catchment containing no remnant vegetation is predicted to be between 50 and 200 times that of a fully vegetated channel network; total phosphorus between 25 and 60 times; total nitrogen between 1.6 and 4.1 times. There are ~48 000 km of streams in the region of which 32% drain areas of remnant vegetation. Of these 17 095 km are above the region's water storage dams. We estimate that decreasing the sediment and phosphorus loads to Moreton Bay by 50% would involve rehabilitating ~6350 km of the channel network below the dams; halving the total nitrogen load would require almost complete restoration of the channel network. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Increased sediment loads from accelerated catchment erosion significantly degrade waterways worldwide. In the South East Queensland region of Australia, sediment loads are degrading Moreton Bay, a Ramsar listed wetland of international significance. In this region, like most parts of coastal Australia, sediment is predominantly derived from gully and channel bank erosion processes. A novel approach is presented that uses carbon and nitrogen stable isotope ratios and elemental composition to discriminate between these often indistinguishable subsoil sediment sources. The conservativeness of these sediment properties is first tested by examining the effect of particle size separation (testing for consistency during transport) and the effect of sampling at different times (testing for temporal source consistency). The discrimination potential of these sediment properties is then assessed with the conservative properties, based on the particle size and temporal analyses, modelled to determine sediment provenance in three catchments. Nitrogen sediment properties were found to have significant particle size enrichment and high temporal variance indicative of non-conservative behaviour. Conversely, carbon stable isotopes had very limited particle size and temporal variability highlighting their suitability for sediment tracing. Channel erosion was modelled to be a significant source of sediment ( μ 51%, σ 9%) contrasting desktop modelling research that estimated gully erosion is the predominant sediment source. To limit the supply of sediment to Moreton Bay, channel bank and gully erosion must both be targeted by sediment management programs. By distinguishing between subsoil sediment sources, this approach has the potential to enhance the management of sediment loads degrading waterways worldwide. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The identification of sediment sources is fundamental to the management of increasingly scarce water resources. Tracing the origin of sediment with elemental geochemistry is a well-established approach to determining sediment provenance. Fundamental to the confident apportionment of sediment to their lithogenic sources is the modelling process. Recent approaches have incorporated distributions throughout the modelling process including source contribution terms for two end-member sources. The shift from modelling source samples to modelling samples drawn from distributions has removed relationships, including potential correlations between elemental concentrations, from the modelling process. Here, we present a novel modelling approach that re-incorporates correlations between elemental concentrations and models distributions for source contribution terms for multiple source end members. Artificial mixtures, based on catchment sources samples, were created to test the accuracy of this correlated distribution model and also examine modelling approaches used in the literature. The most accurate model incorporates correlations between elements, uses the absolute mixing model difference and does not use any weighting. This model was then applied to identify the sources of sediment in three South East Queensland catchments and demonstrated that Quaternary Alluvium is the most dominant source of sediment in these catchments ( μ 44%, σ 12%). This study demonstrates that it is important to understand how different weightings may impact modelling results. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

No abstract is available for this article. © 2021 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

No abstract is available for this article. © 2021 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

No abstract is available for this article. © 2021 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

No abstract is available for this article. © 2021 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

No abstract is available for this article. © 2021 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

No abstract is available for this article. © 2021 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the editor discusses various reports within the issue on topics including use of radionuclides for quantification of soil and rate of redistribution in catchments, sediment source tracing and sediment source fingerprinting techniques in Kharaa River, Mongolia.

Previous studies using fallout radionuclides (137Cs and 210Pbex) to determine the relative contributions of surface-soil and channel erosion (including gullies and channel banks) to stream sediments have used a relatively small number of composite samples (<25) to characterize the source end members, and concentrations in each of the source end members have, through the use of means and standard errors, been assumed to be normally distributed. Here, we examine 137Cs activity concentrations to determine the erosion processes supplying sediment in seven water supply catchments in South-east Queensland. First, we test some of the underlying assumptions in the method using concentrations of 137Cs and 210Pbex in composite samples collected from 109 surface-soil sites and 39 channel-bank sites. Paired composite samples, each consisting of 20 subsamples, from five sites are used to demonstrate that this sampling approach was sufficient to average out any local variations in surface-soil 210Pbex and 137Cs concentrations across the 300 m2 sampled. We derive probability distributions for 137Cs and 210Pbex concentrations in the group of samples from each of the end members and show that only the distribution of 210Pbex in samples from surface soils is normally distributed. We use the probability distributions for 137Cs, which provides the greatest discrimination between sources, to show that the 137Cs concentrations on the river sediment samples are consistent with channel erosion being the dominant source. Conservation works aimed at reducing the supply of sediments in these catchments should therefore focus on rehabilitation of the channel network and decreasing the runoff to the channel network. These findings are consistent with other similar studies on tropical Australian rivers. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

River discharges vary strongly through time and space, and quantifying this variability is fundamental to understanding and modelling river processes. The river basin is increasingly being used as the unit for natural resource planning and management; to facilitate this, basin-scale models of material supply and transport are being developed. For many basin-scale planning activities, detailed rainfall-runoff modelling is neither necessary nor tractable, and models that capture spatial patterns of material supply and transport averaged over decades are sufficient. Nevertheless, the data to describe the spatial variability of river discharge across large basins for use in such models are often limited, and hence models to predict river discharge at the basin scale are required. We describe models for predicting mean annual flow and a non-dimensional measure of daily flow variability for every river reach within a drainage network. The models use sparse river gauging data, modelled grid surfaces of mean annual rainfall and mean annual potential evapotranspiration, and a network accumulation algorithm. We demonstrate the parameterization and application of the models using data for the Murrumbidgee basin, in southeast Australia, and describe the use of these predictions in modelling sediment transport through the river network. The regionalizations described contain less uncertainty, and are more sensitive to observed spatial variations in runoff, than regionalizations based on catchment area and rainfall alone. [ABSTRACT FROM AUTHOR]

This paper proposes a theoretical explanation of the variations of the sediment delivery ratio (SDR) versus catchment area relationships and the complex patterns in the behavior of sediment transfer processes at catchment scale. Taking into account the effects of erosion source types, deposition, and hydrological controls, we propose a simple conceptual model that consists of two linear stores arranged in series: a hillslope store that addresses transport to the nearest streams and a channel store that addresses sediment routing in the channel network. The model identifies four dimensionless scaling factors, which enable us to analyze a variety of effects on SDR estimation, including (1) interacting processes of erosion sources and deposition, (2) different temporal averaging windows, and (3) catchment runoff response. We show that the interactions between storm duration and hillslope/channel travel times are the major controls of peak-value-based sediment delivery and its spatial variations. The interplay between depositional timescales and the travel/residence times determines the spatial variations of total-volume-based SDR. In practical terms this parsimonious, minimal complexity model could provide a sound physical basis for diagnosing catchment to catchment variability of sediment transport if the proposed scaling factors can be quantified using climatic and catchment properties. [ABSTRACT FROM AUTHOR]

A digital terrain model is used with process thresholds to predict the extent of a stable gully network in a 5 km2 catchment of the southeastern highlands of Australia. The model, developed by Dietnch et al. [1992, 1993], predicts the topographic controls on channel networks and interprets these in terms of a critical shear stress for channel incision (τ c) applied by saturation overland flow. We adapt the model slightly to compare the shear stress applied by Hortonian overland flow to that applied by saturation overland flow. The limits to gully erosion in the catchment are controlled strongly by a topographic threshold that has an inverse relationship between upslope catchment area and local gradient. The topographic threshold for channel incision is reproduced using a simple model of Hortonian overland flow and a τ c appropriate for incision into a degraded grass surface (τ c = 245 dyn/cm2). This is consistent with historical evidence for the timing of gully erosion. The study confirms a strong topographic control on the extent of the channel network in a catchment significantly different from the western North America catchments where the topographic threshold was first demonstrated. Despite its simplicity, the model for incision by overland flow appears capable of distinguishing the hydrological processes responsible for channel incision when these are reflected in the relationship between channel network and landscape morphology. The model requires relatively simple inputs, suggesting it may be useful for mapping gully erosion hazard in actively eroding catchments. [ABSTRACT FROM AUTHOR]

The article presents an obituary for lecturer and author Geoffrey Steel Humphreys.

No abstract is available for this article. Copyright © 2018 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

No abstract is available for this article. Copyright © 2018 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This study describes the use of linearly modulated optically stimulated luminescence (LM-OSL) to distinguish surface-soil derived sediments from those derived from channel bank erosion. LM-OSL signals from quartz extracted from 15 surface-soil and five channel bank samples were analysed and compared to signals from samples collected from two downstream river sites. Discriminant analysis showed that the detrapping probabilities of fast, first slow and second slow components of the LM-OSL signal can be used to differentiate between the samples collected from the channel bank and surface-soil sources. We show that for each of these source end members these components are all normally distributed. These distributions are then used to estimate the relative contribution of surface-soil derived and channel bank derived sediment to the river bed sediments. The results indicate that channel bank derived sediments dominate the sediment sources at both sites, with 90.1 ± 3% and 91.9 ± 1.9% contributions. These results are in agreement with a previous study which used measurements of 137Cs and 210Pbex fallout radionuclides to estimate the relative contribution from these two sources. This result shows that LM-OSL may be a useful method, at least in the studied catchment, to estimate the relative contribution of surface soil and channel erosion to river sediments. However, further research in different settings is required to test the difference of OSL signals in distinguishing these sediment sources. And if generally acceptable, this technique may provide an alternative to the use of fallout radionuclides for source tracing. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]