Using sediment tracing to assess processes and spatial patterns of erosion in grazed rangelands, Burdekin River basin, Australia

Highlights This paper presents the first non-modelled estimates of contemporary measured erosion rates against background long term erosion rates in the Great Barrier Reef (GBR) catchments. Using an accelerated erosion factor (AEF), this study has highlighted that there are very specific 'hot-spot' areas that warrant priority treatment in terms of catchment remediation (Bowen sub-catchment, Upper Burdekin sub-catchment and low cover grazing areas). Due to the large intra-catchment variability of erosion in space and time, this study highlights that having a single end of catchment water quality target is inappropriate. Sub-catchment monitoring and evaluation is more suitable. The erosion rates presented in this paper represent a more robust way to 'bench-mark' current erosion rates compared with the current water quality 'targets'. AbstractMethods for prioritising catchment remediation are based on understanding the source of sediment over the short-medium timescales (10-10 2 years) using techniques such as sediment finger-printing, sediment flux monitoring, and catchment modelling. Because such approaches do not necessarily quantify the natural variation in sediment flux over the longer timescale, they often represent background or pre-agricultural erosion rates poorly. This study compares long-term (~100 to >10,000 years) erosion rates derived from terrestrial cosmogenic nuclides ( 10 Be) with contemporary erosion rates obtained by monitoring sediment fluxes over ~5-10 years. The ratio of these two data sets provides a measure of the accelerated erosion factor (AEF), which can be used to identify erosion hot-spots at the sub-catchment scale. The study area is the Burdekin catchment, the largest source of contemporary sediment to the Great Barrier Reef lagoon. Long-term erosion rates vary from <0.0077 mm yr -1 in the Suttor and Belyando subcatchments to 0.0296 mm yr -1 in the Bowen. The contemporary erosion rates are highest on small hillslopes with patchy ground cover (0.2726 mm yr -1 ) and in the Bowen sub-catchment (0.2207 mm yr -1 ), and lowest in the Belyando sub-catchment (0.0019 mm yr -1 ). All but two of the sub-catchment sites have an AEF > 1.0, indicating higher contemporary erosion rates than estimated long-term averages. Results confirm that the contemporary or agriculturally-induced erosion rates at these sites have increased considerably. Within the context of the Reef Water Quality Protection Plan, these results provide justification for water quality targets to be set at the sub-catchment scale, particularly for large and geomorphically diverse catchments.

show abstract

“…Wilkinson et al, 2013). Importantly, application of this approach could be used to help prioritise sub-basins for further tracer analysis.…”

Section: Management Implicationsmentioning

confidence: 99%

“…Once catchments with AEF >1.0 are identified, other techniques can be used to quantify the specific erosion process responsible for the excess sediment (e.g. Leonard and Nott, 2015;Olley et al, 2013;Wilkinson et al, 2013).…”

Section: Comparing the Accelerated Erosion Factor (Aef) Between And Wmentioning

confidence: 99%

Combining contemporary and long-term erosion rates to target erosion hot-spots in the Great Barrier Reef, Australia

et al. 2015

Self Cite

View full text Add to dashboard Cite

show abstract

“…Examination of the range of source and sediment tracer concentrations is an important assessment of the conservative behaviour of each tracer property (Martínez-Carreras, 2010a; Wilkinson et al, 2012;Smith and Blake, 2014). In this study, the range of source tracer concentrations was compared to the range in sediment concentrations for each target downstream sediment sample (reservoirs and channel beds), with those tracer properties falling outside the range in source values being removed from subsequent analysis.…”

Section: Statistical Analysis For Source Discriminationmentioning

confidence: 99%

Evaluating the importance of surface soil contributions to reservoir sediment in alpine environments: a combined modelling and fingerprinting approach in the Posets-Maladeta Natural Park

et al. 2014

View full text Add to dashboard Cite

Abstract. Soil in alpine environments plays a key role in the development of ecosystem services and in order to maintain and preserve this important resource, information is required on processes that lead to soil erosion. Similar to other mountain alpine environments, the Benasque catchment is characterised by temperatures below freezing that can last from November to April, intense rainfall events, typically in spring and autumn, and rugged topography which makes assessment of erosion challenging. Indirect approaches to soil erosion assessment, such as combined model approaches, offer an opportunity to evaluate soil erosion in such areas. In this study (i) the SWAT (Soil and Water Assessment Tool) hydrological and erosion model and (ii) sediment fingerprinting procedures were used in parallel to assess the viability of a combined modelling and tracing approach to evaluate soil erosion processes in the area of the Posets-Maladeta Natural Park (central Spanish Pyrenees). Soil erosion rates and sediment contribution of potential sediment sources defined by soil type (Kastanozems/Phaeozems; Fluvisols and Cambisols) were assessed. The SWAT model suggested that, with the highest specific sediment yields, Cambisols are the main source of sediment in the Benasque catchment and Phaeozems and Fluvisols were identified as the lowest sediment contributors. Spring and winter model runs gave the highest and lowest specific sediment yield, respectively. In contrast, sediment fingerprinting analysis identified Fluvisols, which dominate the riparian zone, as the main sediment source at the time of sampling. This indicates the importance of connectivity as well as potential differences in the source dynamic of material in storage versus that transported efficiently from the system at times of high flow. The combined approach enabled us to better understand soil erosion processes in the Benasque alpine catchment, wherein SWAT identified areas of potential high sediment yield in large flood events but sediment fingerprinting identified areas that, due to high connectivity, contribute more to channel-stored sediment deposits.

show abstract

“…Increase in the grazing pressure causes soil compaction in pasture areas leading to increase of bulk density, thus, decrease of permeability (Pei et al, 2008;Stavi et al, 2008;Du Toit et al, 2009;Cetiner et al, 2012). This situation causes erosion to increase in especially sloping pastures with weak vegetation (Schönbach et al, 2011;Wilkinson et al, 2013). Compaction also have negative effects on plant root development in pastures and root development is limited when the bulk density exceeds the value of 1,85 gr cm-3 (Pierce et al, 1983).…”

Section: Introductionmentioning

confidence: 99%

Düzce yöresinde münavebeli otlatmanın bazı toprak özellikleri üzerine etkisi

Özcan¹

2016

J FAC FOR ISTANBUL U

View full text Add to dashboard Cite

Pastures, one of the four important vegetation types in the world, have great potential not only in terms of forage production for animals, but also in terms of biological diversity. Yet, the pressure of continuous and overgrazing on pastures in Turkey affects both vegetation and soil negatively. Overgrazing leads to soil compaction, thus, soil permeability is influenced in a negative way. It is possible to remove these negative influences via amendment methods or reorganizing grazing. In this study, it was researched how short duration rotational grazing influenced some soil properties in a pasture where uncontrolled heavy grazing for many years in Düzce. As a result of the study, soil properties affected by rotational grazing at most were permeability and bulk density. While the value of bulk density increased from 1.19 gr cm-3 to 1.30 gr cm-3 in the continuous grazing pastures, it decreased from 1.38 gr cm-3 to 1.26 gr cm-3 in the rotational grazing pastures. It was demonstrated in the study that organizing grazing systems in the pastures can improve soil permeability and bulk density to a great extent.

show abstract

Using sediment tracing to assess processes and spatial patterns of erosion in grazed rangelands, Burdekin River basin, Australia

Cited by 220 publications

References 52 publications

Combining contemporary and long-term erosion rates to target erosion hot-spots in the Great Barrier Reef, Australia

Combining contemporary and long-term erosion rates to target erosion hot-spots in the Great Barrier Reef, Australia

Evaluating the importance of surface soil contributions to reservoir sediment in alpine environments: a combined modelling and fingerprinting approach in the Posets-Maladeta Natural Park

Düzce yöresinde münavebeli otlatmanın bazı toprak özellikleri üzerine etkisi

Contact Info

Product

Resources

About