This paper describes the data set from the 6540‐km2 Goulburn River experimental catchment in New South Wales, Australia. Data have been archived from this experimental catchment since its inception in September 2002. Land use in the northern half of the catchment is predominantly cropping and grazing on basalt‐derived soils, with the south being cattle and sheep grazing on sandstone‐derived soils; only the floodplains are cleared of trees in the south. Monitoring sites are mainly concentrated in the nested Merriwa (651 km2) and Krui (562 km2) subcatchments in the northern half of this experimental catchment with a few monitoring sites located in the south. The data set comprises soil temperature and moisture profile measurements from 26 locations; meteorological data from two automated weather stations (data from a further three stations are available from other sources) including precipitation, atmospheric pressure, air temperature and relative humidity, wind speed and direction, soil heat flux, and up‐ and down‐welling short‐ and long‐wave radiation; streamflow observations at five nested locations (data from a further three locations are available from other sources); a total of three surface soil moisture maps across a 40 km × 50 km region in the north from ∼200 measurement locations during intensive field campaigns; and a high‐resolution digital elevation model (DEM) of a 175‐ha microcatchment in the Krui catchment. These data are available on the World Wide Web at http://www.sasmas.unimelb.edu.au.
The process of rill erosion causes significant amounts of sediment to be moved in both undisturbed and disturbed environments and can be a significant issue for agriculture as well as mining lands. Rills also often develop very quickly (from a single rainfall event to a season) and can develop into gullies if sufficient runoff is available to continue their development. This study examines the ability of a terrestrial laser scanner to quantify rills that have developed on fresh and homogeneous mine spoil on an angle of repose slope. It also examines the ability of the SIBERIA erosion model to simulate the rill's spatial and temporal behaviour. While there has been considerable work done examining rill erosion on rehabilitated mine sites and agricultural fields, little work has been done to examine rill development at angle of repose sites. Results show that while the overall hillslope morphology was captured by the laser scanner, with the morphology of the rills being broadly captured, the characteristics of the rills were not well defined. The digital elevation model created by the laser scanner failed to capture the rill thalwegs and tops of the banks, therefore delineating a series of ill defined longitudinal downslope depressions. These results demonstrate that an even greater density of points is needed to capture sufficient rill morphology. Nevertheless, SIBERIA simulations of the hillslope demonstrated that the model was able to capture rill behaviour in both space and time when correct model parameters were used. This result provides confidence in the SIBERIA model and its parameterization. The results demonstrate the sensitivity of the model to changes in parameters and the importance of the calibration process. Figure 2. Photograph of the study site (top) with a digital elevation model (0·2 m by 0·2 m grid) (bottom). This figure is available in colour online at www.interscience.wiley.com/journal/esplFigure 3. Initial hillslope used for the SIBERIA simulations. The digital elevation model grid size is 0·2 m by 0·2 m.Figure 4. Site layout showing scanner locations.
Results
Laser scanning of the slopeProximity to the studied slope was limited by the pond immediately in front of the slope. Initially, the instrument was set up at a location on the other side of the pond, approximately 300 m directly in front of the slope (Figure 4). This initial scan, while successfully capturing the gross morphology of the slope, generated a point cloud that was too sparse in relation to the rills. A second scan was done at a distance of approximately 100 m, but offset to the right of the slope (Figure 4). This location enabled the whole slope to be scanned at a higher resolution, and still without the presence of holes in the dataset created by features in the foreground obscuring more distant objects (known as 'occlusion effects ';Lim et al., 2005;Lichti and Gordon, 2004).I-Site was programmed so that it scanned the slope and surrounding area. This produced a point cloud consisting of approximately 76 000, points with the...
Data describing sediment generation focusing on the temporal evolution of size gradation are required for the prediction of long-term landform evolution. This paper presents such data for the salt weathering of a quartz-chlorite schist obtained from the Ranger Uranium Mine in northern Australia. Rock fragment samples are subjected to three different climate regimes: (1)
[1] The relationship between the rate of rock breakdown and environmental and geological factors must be understood in order to establish the conditions under which weathering limits erosion. In this study qualitative and quantitative models of the rock fragmentation process are fitted to previously published data obtained from laboratory salt weathering trials of quartz-chlorite schist. Weathering was modeled as a combination of (1) a fragmentation event that fragments the parent particle into a number of daughter particles while preserving mass, and (2) a fracture probability, that determines the probability that a fragmentation event will occur in a given time period. We show that observations of the complex breakdown of salt weathered schist are consistent with model assumptions of a simple fracture geometry model and an increase in fracture probability with time. For the fragmentation geometry the best fit to the experimental data was achieved by assuming that each fragmentation event involves splitting of the parent particle into two daughter fragments of equal volume. For the fragmentation rate the data could best be described with a fracture probability, and hence the weathering rate, that increased linearly with time. This paper shows that it is possible to use a physically based fragmentation model to infer the process of fragmentation for individual particles using a time evolving particle size distribution for the weathering rock fragments.Citation: Wells, T., G. R. Willgoose, and G. R. Hancock (2008), Modeling weathering pathways and processes of the fragmentation of salt weathered quartz-chlorite schist,
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