Using rill/interrill comparisons to infer likely responses of erosion to slope length: implications for land management

Soil Research ◽  
1996 ◽  
Vol 34 (4) ◽  
pp. 489 ◽  
Author(s):  
RJ Loch
Keyword(s):  
Land Management ◽  
Overland Flow ◽  
Unit Area ◽  
Management Strategies ◽  
Residue Management ◽  
Moderate Increase ◽  
Vegetative Cover ◽  
Slope Length ◽  
Erosion Rates ◽  
Erosion Processes

With the release of the Revised Universal Soil Loss Equation (RUSLE) there is potential to consider a range of responses of erosion to increasing slope length. This paper presents data to illustrate commonly observed effects of increasing overland flow on erosion processes and erosion rates, and considers the application of the data to specifying land management strategies and forms of vegetative cover most suited to particular soils. It also discusses a methodology for assessing relevant slope length factors for the RUSLE based on rill/interrill susceptibility. Three basic responses to slope length are noted: (i) little increase in erosion per unit area with increasing length, due to either the failure of rills to develop for the range of overland flows considered, or rill formation at very low hows with no further increase in erosion rates as flow rates increase; (ii) moderate increase in erosion per unit area with slope length associated with slight rill development; and (iii) large increases in erosion per unit area with slope length as rilling develops strongly. These responses have significance for the relative importance of surface and contact cover (and therefore, for the plant species grown and/or residue management strategy adopted), and for the use of contour banks to reduce slope length.

Impact of vegetative cover and slope on runoff, erosion, and water quality for field plots on a range of soil and spoil materials on central Queensland coal mines

Soil Research ◽  
2000 ◽  
Vol 38 (2) ◽  
pp. 313 ◽  
Author(s):  
C. Carroll ◽  
L. Merton ◽  
P. Burger
Keyword(s):  
Water Quality ◽  
Soil Erosion ◽  
Overland Flow ◽  
Salt Content ◽  
Vegetative Cover ◽  
Rhodes Grass ◽  
Erosion Rates ◽  
Mine Sites ◽  
The Impact ◽  
Field Plots

In 1993, a field study commenced to determine the impact of vegetative cover and slope on runoff, erosion, and water quality at 3 open-cut coal mine sites. Runoff, sediment, and water quality were measured on 0.01-ha field plots from 3 slope gradients (10, 20, 30%), with pasture and tree treatments imposed on soil and spoil material, and 2 soil and spoil plots left bare. The greatest soil erosion occurred before pasture cover established, when a large surface area of soil (>0.5 plot area) was exposed to rainfall and overland flow. Once buffel grass (Cenchrus ciliaris) colonised soil plots, there were negligible differences in soil erosion between slope gradients. On spoil, Rhodes grass (Chloris gayana) reduced in situ soluble salt content, and reduced runoff electrical conductivity to levels measured in surrounding creeks. Where spoil crusted there was poor vegetative growth and unacceptably large runoff and erosion rates throughout the study.

Effects of vegetation cover on runoff and erosion under simulated rain and overland flow on a rehabilitated site on the Meandu Mine, Tarong, Queensland

Soil Research ◽  
2000 ◽  
Vol 38 (2) ◽  
pp. 299 ◽  
Author(s):  
R. J. Loch
Keyword(s):  
Overland Flow ◽  
Extreme Rainfall ◽  
Rainfall Runoff ◽  
Vegetative Cover ◽  
Erosion Rates ◽  
Overland Flows ◽  
Simulated Rain ◽  
Runoff Events ◽  
Flow Study

This research was carried out to quantify the role of vegetative cover in reducing runoff and erosion from rehabilitated mined land. Duplicate plots 1.5 m wide and 12 m long were prepared on a rehabilitated area of the Meandu Mine, Tarong, with vegetative cover of 0, 23%, 37%, 47%, and 100%. The area had a uniform 15% slope, and there were no rill or gully lines present. Simulated rain equivalent to a 1 : 100 year storm was applied to the plots, and runoff and erosion were measured. Infiltration totals and rates increased strongly with increasing vegetative cover. There was visibly greater infiltration under vegetation. Erosion from the simulated storm was greatly reduced by vegetative cover, declining from 30–35 t/ha at 0% vegetative cover to 0.5 t/ha at 47% cover. Reductions in erosion at lower levels of vegetative cover were greater than predicted by the cover/erosion relationship used in the USLE. The dominantly stoloniferous growth habit of the grass at this site may have increased the effectiveness of vegetative cover in this study. To allow the data to be extrapolated to slopes longer than 12 m, a series of overland flows were applied to the upslope boundaries of the plots, simulating flows on slopes up to 70 m long. Detachment and transport of sediment by applied overland flow was similarly reduced by vegetative cover, and results from the overland flow study also indicate that for slopes up to 70 m long with grass cover of 47% or greater, erosion rates will be minimal, even under extreme rainfall/runoff events.

Tillage erosion intensity in the South Canterbury Downlands, New Zealand

Soil Research ◽  
2003 ◽  
Vol 41 (4) ◽  
pp. 789 ◽  
Author(s):  
Timothy A. Quine ◽  
Les R. Basher ◽  
Andrew P. Nicholas
Keyword(s):  
Full Range ◽  
Management Strategies ◽  
Slope Length ◽  
Erosion Rates ◽  
Dominant Soil ◽  
Mouldboard Plough ◽  
Soil Translocation ◽  
Tillage Erosion ◽  
Erosion Intensity

Growing awareness of the pressure on land resources emphasises the need to understand the full range of processes operating in human-impacted agroecosystems. In such systems one of the greatest threats to long-term sustainability is the erosion and depauperation of soil, which, until recently, was attributed almost entirely to water erosion. This study builds on recent awareness of the significance of tillage erosion and presents the results of an experimental investigation of tillage erosion due to mouldboard ploughing. Aluminium cubes were used to trace soil translocation as a result of a single pass of the plough perpendicular to the contour in downslope and upslope directions. In common with others studies, translocation was found to be directly proportional to slope tangent for downslope tillage and unrelated to slope for upslope tillage. The influence of non-topographic variables on the relationship between translocation distance and slope was partially filtered out by using the ratio of translocation distances in the tillage direction and perpendicular to tillage. Shallow plough depths of 0.17 m produced tillage detachment of only 230 kg/m2; however, a high tillage translocation coefficient of 1.16 m/pass resulted in a soil flux coefficient of 265 kg/m.pass. The high tillage translocation coefficient is probably partly due to the loose nature of the regularly cultivated loessic soil, however, on the basis of comparison with other published studies, it is suggested that the high tillage speed of 7 km/h is the principal control on the magnitude of the coefficient. Analysis of the available data suggests that a 30% reduction in tillage erosion intensity could be obtained by reduction of the tillage speed to 4 km/h; nevertheless, more experimental work is needed to test this suggestion. On the transect studied, a pair of opposing passes of the mouldboard plough would produce erosion rates as high as 5.1 kg/m2.year (51 t/ha.year) from shoulder slope elements and as high as 1.9 kg/m2.year (19 t/ha.year) over half of the slope length. This pattern matched closely the distribution of 137Cs-derived erosion rates documented previously for a nearby field, suggesting that for this environment, as for many mechanised agricultural systems, tillage erosion is the dominant soil redistribution process and the greatest threat to long-term sustained on-site productivity. Reduction of tillage erosion should, therefore, be seen as a priority in the development of sustainable land management strategies.

scholarly journals Changes in land-use and their impact on erosion rates and overland flow generation in the Maghreb region

2005 ◽  
Vol 17 (2) ◽  
pp. 163-180 ◽  
Author(s):  
C. O.A. Coelho ◽  
A. J.D. Ferreira ◽  
A. Laouina ◽  
A.-K. Boulet ◽  
M. Chaker ◽  
...  
Keyword(s):  
Land Use ◽  
Soil Erosion ◽  
Land Management ◽  
Overland Flow ◽  
Animal Husbandry ◽  
Rainfall Simulation ◽  
Management Systems ◽  
Simulation Experiments ◽  
Erosion Hazard ◽  
Erosion Rates

The ongoing intensification of grazing as well as the replacement of traditional land management systems in the Maghreb has brought to the forefront the fundamental role of land-use in determining soil erosion hazard. This paper reports on erosion rates and soil hydrological characteristics of a variety of land uses in Morocco and Tunisia. The results were obtained through rainfall simulation experiments carried out in the field using a portable simulator, following the design of CERDÀ et al. (1997). Traditional land management systems - typically involving a combination of agriculture, animal husbandry and forestry - produced the least amounts of overland flow and the lowest soil erosion rates. Over-exploitation of these systems apparently has only minor hydrological and erosional impacts. Heavily grazed, degraded "maquis" shrublands, on the other hand, produced considerable amounts of overland flow. At the plot scale of the rainfall simulation experiments (0.24 m2), the corresponding sediment loads are rather insignificant. Nevertheless, slopes where "maquis" shrublands (which generally have very compacted soils) occur upslope from more erodible soils may present a major erosion hazard.

scholarly journals The Beast from the East: impact of an atypical cold weather event on hydrology and nutrient dynamics in two Irish catchments

2020 ◽  
Author(s):  
S.E. Vero ◽  
N.T. McDonald ◽  
G. McGrath ◽  
P.-E. Mellander
Keyword(s):  
Land Management ◽  
Nutrient Dynamics ◽  
Overland Flow ◽  
Time Lag ◽  
Management Strategies ◽  
Cold Weather ◽  
Catchment Scale ◽  
Continuous Stream ◽  
Baseline Information ◽  
Flow Pathways

A historic lack of continuous stream nutrient monitoring at the catchment scale limits understanding of the effects of snowstorms. The most significant snowstorm since 1985, nicknamed “the Beast from the East”, occurred in February–March 2018. High-frequency stream outlet monitoring in two close but hydrologically and agriculturally contrasting catchments (<1,200 ha) captured phosphorus (total and reactive), total oxygenated nitrogen (TON), temperature and discharge dynamics during and after the event. The grassland catchment consists of poorly drained gley soils and exhibits overland flow pathways, while the arable catchment consists of well-drained brown earths and is dominated by subsurface pathways. Nitrate (NO 3 -N) concentrations were initially elevated (3.50 and 7.89 mg/L for poorly drained grassland and well-drained arable catchments, respectively) before becoming diluted by meltwater. Total reactive phosphorus (TRP) displayed a distal (anti-clockwise) concentration-discharge hysteresis in the poorly drained grassland catchment suggesting low mobilisation from the soil. Conversely, the well-drained arable catchment displayed proximal (clockwise) hysteresis, indicative of the mobilisation from stream and bank sediment. These relatively infrequent snow events behave similarly to heavy rainfall as regards nutrient losses, albeit subject to a time-lag induced by the speed of snowmelt and the soil moisture deficit (SMD) prior to snowfall. Antecedent land management is crucial to mitigate risk. The current absence of records and analyses of catchment response, particularly nutrient dynamics, to atypical cold weather events in Ireland limits understanding of their effects on water quality. The present study provides the first such baseline information from which land management strategies and the implications for attaining environmental targets can be explored.

scholarly journals Soil Erosion and Controls in the Slope-Gully System of the Loess Plateau of China: A Review

2021 ◽  
Vol 9 ◽  
Author(s):  
Bingbing Zhu ◽  
Zhengchao Zhou ◽  
Zhanbin Li
Keyword(s):  
Soil Erosion ◽  
Loess Plateau ◽  
Overland Flow ◽  
Vegetation Pattern ◽  
Sediment Source ◽  
The Loess Plateau ◽  
Erosion Process ◽  
Slope Length ◽  
Base Level ◽  
Erosion Processes

The Loess Plateau has long been suffering from serious soil erosion of which erosion from the slope-gully system is now dominant. The slope-gully system is characterized with distinctive erosion distribution zones consisting of inner and inter gully areas wherein erosion patterns spatially vary, acting as both sediment source and the dominant sediment and water transport mechanism. In this paper, a substantial body of research is reviewed concentrating on the soil erosion processes and control practices in the slope-gully system. The inner gully area is identified as the main sediment source while runoff and sediment from the inter-gully upland is found to significantly affect down slope erosion processes. Correspondingly, the protective vegetation pattern and coverage should be strategically designed for different erosion zones with an emphasis on the critical vegetation cover and pattern to reduce sediment yield of the whole slope-gully system. Check-dam could change the base level of erosion and reduce the slope length of the gully side, which will further decrease the possibility and magnitude of gravity erosion. We concluded that understanding the erosion processes and implementing erosion practices for the slope-gully system are of importance and require more research efforts that emphasize: 1) the influence of upland runoff on erosion processes at downslope; 2) the relationship between hydraulic characteristics of overland flow and erosion process at a slope-gully system scale; 3) physical mechanisms of different vegetation patterns on the slope-gully erosion process.

Estimation of erosion model erodibility parameters from media properties

Soil Research ◽  
2000 ◽  
Vol 38 (2) ◽  
pp. 265 ◽  
Author(s):  
G. J. Sheridan ◽  
H. B. So ◽  
R. J. Loch ◽  
C. M. Walker
Keyword(s):  
Overland Flow ◽  
Prediction Models ◽  
Field Capacity ◽  
Stepwise Multiple Regression ◽  
Organic Carbon Content ◽  
Regression Equations ◽  
Sediment Delivery ◽  
Data Set ◽  
Erosion Rates ◽  
Erosion Processes

The aim of this research was to enable erodibility values for hillslope-scale erosion prediction models to be determined from easily measured media properties. Simulated rainfall and overland flow experiments were carried out on 34 soils and overburdens from 15 Queensland open-cut coal mines at The University of Queensland Erosion Processes Laboratory. Properties of the 34 media determined included aggregate stability, Atterberg limits, bulk density, cation exchange capacity, dispersion ratios, electrical conductivity, exchangeable sodium percentage, organic carbon content, pH, texture, and water content at field capacity and wilting point. Correlation and stepwise multiple regression procedures were used to determine those media properties that could best be used to predict rill and interill erodibility. Correlations between media properties and sediment delivery at each of 5, 10, 15, 20, and 30% slope revealed that different media properties were correlated with erosion rates at different slopes. A media property could show a strong correlation with erodibility at 30% slope, and a low correlation at 5% slope. Splitting the data set into soils only, and overburdens only, showed that properties that were positively correlated with erosion rates for one group could be negatively correlated for the other group. Therefore, in this study, erodibility could not be explicitly linked to one set of media properties for all medium types and erosive conditions. It was concluded that a single regression equation could not be used to predict erodibility under all conditions. Instead, 4 equations were developed to predict rill and interill erodibility, for soils and overburdens separately. The need for separate regression equations was attributed to the presence of different erosive sub-processes for specific combinations of medium type and slope gradient.

scholarly journals Hydrogeomorphic processes affecting dryland gully erosion: Implications for modelling

2018 ◽  
Vol 43 (1) ◽  
pp. 46-64 ◽  
Author(s):  
Roy C. Sidle ◽  
Ben Jarihani ◽  
SanLinn Ismail Kaka ◽  
Jack Koci ◽  
Abdulaziz Al-Shaibani
Keyword(s):  
Land Management ◽  
Management Practices ◽  
Overland Flow ◽  
Ground Cover ◽  
Gully Erosion ◽  
Annual Rainfall ◽  
Surface Erosion ◽  
Distributed Data ◽  
Erosion Processes ◽  
Sediment Loads

Gullies contribute high sediment loads to receiving waters and significantly degrade landscapes. In drylands, low annual rainfall and resultant poor ground cover, coupled with high-intensity storms and dispersive soils, predispose these landscapes to gully erosion. Land management, such as grazing, exacerbates gully-forming processes by degrading ground cover and compacting soils, thereby increasing and concentrating overland flow. Current surface erosion models do not adequately represent sediment export from gullied terrain due to lack of distributed data and complex hydrogeomorphic processes, such as overland flow concentration, waterfall erosion, soil pipe collapse, and mass wasting. Here, we outline the strengths and weaknesses of past modelling approaches in erodible terrain and focus on how gully erosion processes can be better simulated at appropriate scales using newly available remote-sensing techniques and databases, coupled with improved understanding of relevant hydrogeomorphic processes. We also discuss and present examples of challenges related to assessing land management practices in drylands that affect gully erosion.

scholarly journals Vegetation, ground cover, soil, rainfall simulation, and overland-flow experiments before and after tree removal in woodland-encroached sagebrush steppe: the hydrology component of the Sagebrush Steppe Treatment Evaluation Project (SageSTEP)

2020 ◽  
Vol 12 (2) ◽  
pp. 1347-1365 ◽  
Author(s):  
C. Jason Williams ◽  
Frederick B. Pierson ◽  
Patrick R. Kormos ◽  
Osama Z. Al-Hamdan ◽  
Justin C. Johnson
Keyword(s):  
Experimental Data ◽  
Overland Flow ◽  
Surface Soil ◽  
Ground Cover ◽  
Rainfall Simulation ◽  
Sagebrush Steppe ◽  
Erosion Rates ◽  
Erosion Processes ◽  
Tree Removal ◽  
Flow Experiments

Abstract. Rainfall simulation and overland-flow experiments enhance understanding of surface hydrology and erosion processes, quantify runoff and erosion rates, and provide valuable data for developing and testing predictive models. We present a unique dataset (1021 experimental plots) of rainfall simulation (1300 plot runs) and overland-flow (838 plot runs) experimental plot data paired with measures of vegetation, ground cover, and surface soil physical properties spanning point to hillslope scales. The experimental data were collected at three sloping sagebrush (Artemisia spp.) sites in the Great Basin, USA, each subjected to woodland encroachment and with conditions representative of intact wooded shrublands and 1–9 years following wildfire, prescribed fire, and/or tree cutting and shredding tree-removal treatments. The methodologies applied in data collection and the cross-scale experimental design uniquely provide scale-dependent, separate measures of interrill (rain splash and sheet flow processes, 0.5 m2 plots) and concentrated overland-flow runoff and erosion rates (∼9 m2 plots), along with collective rates for these same processes combined over the patch scale (13 m2 plots). The dataset provides a valuable source for developing, assessing, and calibrating/validating runoff and erosion models applicable to diverse plant community dynamics with varying vegetation, ground cover, and surface soil conditions. The experimental data advance understanding and quantification of surface hydrologic and erosion processes for the research domain and potentially for other patchy-vegetated rangeland landscapes elsewhere. Lastly, the unique nature of repeated measures spanning numerous treatments and timescales delivers a valuable dataset for examining long-term landscape vegetation, soil, hydrology, and erosion responses to various management actions, land use, and natural disturbances. The dataset is available from the US Department of Agriculture National Agricultural Library at https://data.nal.usda.gov/search/type/dataset (last access: 7 May 2020) (doi: https://doi.org/10.15482/USDA.ADC/1504518; Pierson et al., 2019).

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