Soil Erosion Assessment Research Articles

Quantitative assessment of pedodiversity and soil erosion within a karst sinkhole in the dry steppe subzone

A detailed study of the soil cover of a sinkhole (300 m2) in the dry steppe landscape of the Bogdinsk–Baskunchak Natural Reserve in Astrakhan oblast has been performed, and the factors of its differentiation have been analyzed. The indices of pedodiversity have been calculated and compared for karst sinkholes in the dry steppe and northern taiga landscapes. Quantitative parameters of the lateral migration of solid soil substances on the slopes of the sinkhole have been determined. The rate of soil erosion decreases from the slope of southern aspect to the slopes of western, northern, and eastern aspects. On the average, it is estimated at 0.4 mm/yr. The average rate of accumulation of solid substances on the lower parts of the slopes and in the bottom of the sinkhole reaches 0.74 mm/yr. A comparative analysis of the soil properties attests to their dependence on the particular position of a given soil within the sinkhole. Downward the slopes of the sinkhole, full-profile brown arid soils (Cambic Calcisols) are replaced by sierozem-like soils (Haplic Calcisols), light-humus poorly developed soils (Luvisols), lithozems (Leptosols), and stratified soils (stratozems, or Colluvic Regosols). The soils within the upper ring-shape soil microzone are more diverse and contrasting with respect to their morphological, physical, chemical, and physicochemical properties. The degree of soil contrasts decreases down the slopes of the sinkhole towards its bottom. The studied sinkhole is characterized by considerable pedodiversity. Quantitative parameters of pedodiversity for the sinkhole in the dry steppe zone are higher than those form the sinkholes in the northern taiga zone.

Field assessment of surface runoff, sediment yield and soil erosion in the opencast mines in Chirimiri area, Chhattisgarh, India

Chirimiri Coal field is located in the Koriya district of Chhattisgarh state of India. It lies in the valley of the Hasdeo River and is spread over 125 km2 area. Ever increasing problem of declining forest resources and water quality is a cause of concern particularly due to excessive soil erosion resulting in soil sediment deposition from the overburdened dump. Dwindling resources has compelled the policy makers to search for alternatives such as waste lands and mined areas to improve soil and water resources for use in agriculture and allied sectors while maintaining the local ecology and hydrology. Most Opencast mines release huge amount of mining wastes in the form of overburden dump (OBD) materials that are prone to soil erosion and also create problems of sedimentation and deteriorating water quality, affecting agriculture. Historical daily rainfall data for 21 years and daily surface runoff as estimated by SCS-Curve Number method were analysed. Sediment yield was estimated at lower end of erosion face of OBD and near drainage outlet of opencast mine. Assessment of soil erosion from OBD materials was made byRevised Universal Soil Loss Equation (RUSLE) method and was compared with direct field measurements by placing plastic sheets in downstream portion of OBD. As a result monsoon rainfall constitutes 91.6 percent of the annual rainfall and surface runoff constitutes 31.7 percent of monsoon rainfall. The surface runoff was found to be 4133 m3/ha while the sediment yield of drainage effluent was negligible. The soil loss from OBD as estimated by the RUSLE method (62.7 t ha−1 yr−1) was quite close (+13.2 percent) to the direct field measurement 54.44 t ha−1. The sediment samples from OBD were found acidic in nature and exhibited low values of Electrical Conductivity (EC), Organic Content (OC), Water Holding Capacities (WHC), and Available Nitrogen (N), Phosphorus (P) and Potassium (K). For controlling soil erosion of OBD, mechanical and vegetative measures have been suggested along with installation of sediment traps inside and outside the mines. There is good scope to backfill the mines with the OBD in the form of well laid out terraces to support plantation. This can be eventually used for leguminous fodder/grass production.

Assessing soil erosion using USLE model and MODIS data in the Guangdong, China

In this study, soil erosion in the Guangdong, China during 2012 was quantitatively assessed using Universal Soil Loss Equation (USLE). The parameters of the model were calculated using GIS and MODIS data. The spatial distribution of the average annual soil loss on grid basis was mapped. The estimated average annual soil erosion in Guangdong in 2012 is about 2294.47t/ (km2.a). Four high sensitive area of soil erosion in Guangdong in 2012 was found. The key factors of these four high sensitive areas of soil erosion were significantly contributed to the land cover types, rainfall and Economic development and human activities.

Set-up and calibration of a portable small scale rainfall simulator for assessing soil erosion processes at interrill scale

A portable rainfall simulator was built for assessing runoff and soil erosion processes at interrill scale. Within this study, requirements and constraints of the rainfall simulator are identified and discussed. The focus lies on the calibration of the simulator with regard to spatial rainfall homogeneity, rainfall intensity, drop size, drop fall velocity and rainfall kinetic energy. These parameters were obtained using different methods including a Laser Precipitation Monitor. A detailed presentation of the operational characteristics is given. The presented rainfall simulator setup featured a rainfall intensity of 45.4 mm·h-1 with a spatial homogeneity of 80.4% based on a plot area of 0.64 m². Because of the comparatively low drop height (2 m), the diameter-dependent terminal fall velocity (1.87 m·s-1) was lower than benchmark values for natural rainfall. This conditioned also a reduced rainfall kinetic energy (4.6 J·m-2·mm-1) compared to natural rainfall with same intensity. These shortfalls, a common phenomenon concerning portable rainfall simulators, represented the best possible trade-off between all relevant rainfall parameters obtained with the given simulator setup. Field experiments proved that the rainfall erosivity was constant and replicable.

Assessment of soil erosion in a tropical mountain river basin of the southern Western Ghats, India using RUSLE and GIS

Revised Universal Soil Loss Equation (RUSLE) model coupled with transport limited sediment delivery (TLSD) function was used to predict the longtime average annual soil loss, and to identify the critical erosion-/deposition-prone areas in a tropical mountain river basin, viz., Muthirapuzha River Basin (MRB; area = 271.75 km2), in the southern Western Ghats, India. Mean gross soil erosion in MRB is 14.36 t ha−1 yr−1, whereas mean net soil erosion (i.e., gross erosion–deposition) is only 3.60 t ha−1 yr−1 (i.e., roughly 25% of the gross erosion). Majority of the basin area (∼86%) experiences only slight erosion (<5 t ha−1 yr−1), and nearly 3% of the area functions as depositional environment for the eroded sediments (e.g., the terraces of stream reaches, the gentle plains as well as the foot slopes of the plateau scarps and the terrain with concordant summits). Although mean gross soil erosion rates in the natural vegetation belts are relatively higher, compared to agriculture, settlement/built-up areas and tea plantation, the sediment transport efficiency in agricultural areas and tea plantation is significantly high, reflecting the role of human activities on accelerated soil erosion. In MRB, on a mean basis, 0.42 t of soil organic carbon (SOC) content is being eroded per hectare annually, and SOC loss from the 4th order sub-basins shows considerable differences, mainly due to the spatial variability in the gross soil erosion rates among the sub-basins. The quantitative results, on soil erosion and deposition, modelled using RUSLE and TLSD, are expected to be beneficial while formulating comprehensive land management strategies for reducing the extent of soil degradation in tropical mountain river basins.

USLE-based assessment of soil erosion by water in the watershed upstream Tessaoute (Central High Atlas, Morocco)

This study involves a loss of soil modeling in the catchment basin of Tessaoute upstream (Central High Atlas, Morocco), the integration of the universal soil loss equation in Wischmeier (USLE) in a Geographical Information System (GIS). The model allows a qualitative and quantitative assessment of water erosion. The various factors of water erosion (climate, topography, soil, land use and erosion control practices) were mapped, processed, sorted and merged in order to quantify the water erosion rate per unit area. The result is a quantitative map, spatial reference, with an average loss of about 15.44 t/ha/year by runoff sheet and rill. This allowed us to better understand the impact of each erosive factor, assess its contribution to soil loss and establish the decisive factors that control water erosion in the watershed in order of importance, slope, soil erodibility and vegetation cover.

English

English

Soil Erosion Assessment in Tasik Chini Catchment using Remote Sensing and GIS Techniques

Over many years, forested land transformation into urban, agriculture and mining areas within Tasik Chini Catchment become more intense. These activities have negatively affected the catchment through soil erosion and increased the amount of sediments that deposited into the lake. Hence, the present study aimed to estimate soil erosion risk within Tasik Chini Catchment integrating the Revised Universal Soil Loss Equation (RUSLE) model and remotely sensed geospatial data. The multispectral imagery from LANDSAT 8 was used to provide up to date information on land cover within the catchment. The result shows the majority of Tasik Chini Catchment is classified at very low class ( 150 ton ha−1 yr−1) with total area of 120.04 ha (2.30%). Tasik Chini Catchment is very susceptible to soil erosion especially on northwest and southeast regions, where the main sources of soil loss come from the agricultural, new settlements and mining activities. To conclude, the estimation of soil erosion model using remotely sensed data can be used to build sustainable development strategy within Tasik Chini Catchment in the future.

On the role of “internal variability” on soil erosion assessment

On the role of “internal variability” on soil erosion assessment

Spatial assessment of soil erosion in Alqerdaha basin (Syria)

The objective of this paper is the assessment of soil erosion rate and its spatial distribution in Alqerdaha basin (West of Syria) with a surface area 217 km2. The study was conducted using Universal soil loss equation (USLE) model due to its modest data demand and easy comprehensible structure. Soil erosion affected by rainfall erosivity, soil erodibility, topography, vegetation, and conservation support practice factors. According to USLE model, soil erosion was modeled through the production of raster maps of previous factors and multiplied it using GIS and RS techniques. The results show that 12.9% of the study basin has a very low erosion of soil, 20.7% low erosion, 31.3% moderate erosion, 26.3% high erosion, and 8.8% a very high erosion. These results will be useful for soil conservation management and the planning of mitigation measures.

Role of GIS in Soil Erosion

Soil erosion is defined as the physical degradation of the landscape over time. The process is initiated when soil particles are detached from its original configuration by erosive forces such as rainfall. The soil particles may then be transported by overland flow into nearby rivers and oceans. Current developments in geographic information systems (GIS) make it possible to model complex spatial information. A GIS is used in this project to determine how soil erosion potential varies throughout a watershed. A method was developed in this research which combines the Universal Soil Loss Equation (USLE). The USLE calculates long-term average annual soil loss by multiplying six specific factors which describe the watershed characteristics such as rainfall, soil types, slope, and vegetation cover. The GIS is used to store the USLE factors as individual digital layers and multiplied together to create a soil erosion potential map. This combination provides a way to assess soil erosion potential of an area with existing data sources.

Scenario simulation of land exploitation and risk assessment of soil erosion in the low-slope hilly area of the Erhai basin

Risk assessment of soil erosion is an important prerequisite to develop the low-slope hilly in basin-scale. Using Dynamics of Land System model (DLS), we design the scenario simulation of land exploitation of Dali city which is located in the Erhai basin and typical as low-slope hilly area. Then we bring in Universal Soil Loss Equation (USLE) to assess the risks of soil erosion under different scenarios. In two simulating scenarios, baseline scenario and planning scenario respectively, the spatial distribution pattern of land use of the study area in 2020 shows an overall consistency and a partial difference. The cultivated resources of Dali has been protected since the cultivated land located in dam area has not changed, while construction land has expanded more or less on the basis of existing built-up areas. Specifically, the expansion of construction land in planning scenario is concentrated on Haidong town and Fengyi town where there are rich in low-slope hilly resources. In two scenarios mentioned above, both the value-at-risk of soil erosion and its risk level have no significant rise or drop from 2008 to 2020. As the risk index of soil erosion in baseline scenario is 0.003 taller than in planning scenario, one conclusion can be drawn that the planning scenario will lower the overall risk of soil erosion and should be used to develop gentle hillside area in Erhai basin. The risk evaluation of soil erosion under different scenarios is valuable for land management decisions because the results provide fundamental information for optimal utilization of land use and prevention of ecological risks in the low-slope hilly regions.

Vulnerability Assessment of Soil Erosion Based on Topography and Vegetation Cover in a Developing City of Orlu L.G.A, South East Nigeria

Vulnerability Assessment of Soil Erosion Based on Topography and Vegetation Cover in a Developing City of Orlu L.G.A, South East Nigeria

Evaluation of water erosion risk of Badinska River catchment, Southwest Bulgaria

This investigation has been carried out at Badinska River watershed - one of the most famous torrents in Bulgaria. The purpose of the survey is tos analyse the main erosion factors and erosion potential of territories, with a view to assess soil erosion risk and opportunity of high water formation from watershed. A methodical approach for determination and mapping of the territories in terms of the class of erosion risk with the use of GIS is applied. Assessments are made according to the ?Methodology for preparing the national long term programme for protection against erosion and flooding in forestlands?. The total assessment for Badinska river watershed is ?low to moderate? potential risk and ?very low to low? actual erosion risk. About of 5% of the forest stock territory is with ?moderate? and ?moderate to high? actual risk, and the biggest part of this territory (about 63%) is in the main stream watershed above the Yaloviko tributary.

Assessment of Soil Degradation by Erosion Based on Analysis of Soil Properties Using Aerial Hyperspectral Images and Ancillary Data, Czech Republic

The assessment of the soil redistribution and real long-term soil degradation due to erosion on agriculture land is still insufficient in spite of being essential for soil conservation policy. Imaging spectroscopy has been recognized as a suitable tool for soil erosion assessment in recent years. In our study, we bring an approach for assessment of soil degradation by erosion by means of determining soil erosion classes representing soils differently influenced by erosion impact. The adopted methods include extensive field sampling, laboratory analysis, predictive modelling of selected soil surface properties using aerial hyperspectral data and the digital elevation model and fuzzy classification. Different multivariate regression techniques (Partial Least Square, Support Vector Machine, Random forest and Artificial neural network) were applied in the predictive modelling of soil properties. The properties with satisfying performance (R2 &gt; 0.5) were used as input data in erosion classes determination by fuzzy C-means classification method. The study was performed at four study sites about 1 km2 large representing the most extensive soil units of the agricultural land in the Czech Republic (Chernozems and Luvisols on loess and Cambisols and Stagnosols on crystalline rocks). The influence of site-specific conditions on prediction of soil properties and classification of erosion classes was assessed. The prediction accuracy (R2) of the best performing models predicting the soil properties varies in range 0.8–0.91 for soil organic carbon content, 0.21–0.67 for sand content, 0.4–0.92 for silt content, 0.38–0.89 for clay content, 0.73–089 for Feox, 0.59–0.78 for Fed and 0.82 for CaCO3. The performance and suitability of different properties for erosion classes’ classification are highly variable at the study sites. Soil organic carbon was the most frequently used as the erosion classes’ predictor, while the textural classes showed lower applicability. The presented approach was successfully applied in Chernozem and Luvisol loess regions where the erosion classes were assessed with a good overall accuracy (82% and 67%, respectively). The model performance in two Cambisol/Stagnosol regions was rather poor (51%–52%). The results showed that the presented method can be directly and with a good performance applied in pedologically and geologically homogeneous areas. The sites with heterogeneous structure of the soil cover and parent material will require more precise local-fitted models and use of further auxiliary information such as terrain or geological data. The future application of presented approach at a regional scale promises to produce valuable data on actual soil degradation by erosion usable for soil conservation policy purposes.

Soil erosion assessment—Mind the gap

AbstractAccurate assessment of erosion rates remains an elusive problem because soil loss is strongly nonunique with respect to the main drivers. In addressing the mechanistic causes of erosion responses, we discriminate between macroscale effects of external factors—long studied and referred to as “geomorphic external variability”, and microscale effects, introduced as “geomorphic internal variability.” The latter source of erosion variations represents the knowledge gap, an overlooked but vital element of geomorphic response, significantly impacting the low predictability skill of deterministic models at field‐catchment scales. This is corroborated with experiments using a comprehensive physical model that dynamically updates the soil mass and particle composition. As complete knowledge of microscale conditions for arbitrary location and time is infeasible, we propose that new predictive frameworks of soil erosion should embed stochastic components in deterministic assessments of external and internal types of geomorphic variability.

Soil erosion risk assessment using GIS and CORINE model: a case study from western Shiraz, Iran

ABSTRACTThis study employs the Coordination of Information on the Environment (CORINE) model with geographic information system to assess soil erosion risk for restoring and protecting areas within the Bonrod Zangane watershed, western Shiraz, Iran. Actual soil erosion risk was determined by combining two main parameters including potential soil erosion risk and vegetation cover. The potential soil erosion risk was generated by integrating soil erodibility, erosivity and slope parameters. Soil texture, depth and stoniness layers were overlaid to form a soil erodibility map. Modified Fournier index and Bagnouls–Gaussen aridity index were integrated to generate the erosivity layer. The slope classes also were generated from digital elevation model. In order to estimate vegetative land cover, the normalized difference vegetation index (NDVI) was used. The raster-based layers were then integrated to produce erosion risk map. The results showed that 34.7% of the study area has high and only 31.4% of the study area has low soil erosion risk. It is concluded that CORINE model can be used to delineate the soil erosion risk and also to discriminate the potential soil erosion risk areas.

Monitoring and assessment of soil erosion at micro-scale and macro-scale in forests affected by fire damage in northern Iran.

Understanding the occurrence of erosion processes at large scales is very difficult without studying them at small scales. In this study, soil erosion parameters were investigated at micro-scale and macro-scale in forests in northern Iran. Surface erosion and some vegetation attributes were measured at the watershed scale in 30 parcels of land which were separated into 15 fire-affected (burned) forests and 15 original (unburned) forests adjacent to the burned sites. The soil erodibility factor and splash erosion were also determined at the micro-plot scale within each burned and unburned site. Furthermore, soil sampling and infiltration studies were carried out at 80 other sites, as well as the 30 burned and unburned sites, (a total of 110 points) to create a map of the soil erodibility factor at the regional scale. Maps of topography, rainfall, and cover-management were also determined for the study area. The maps of erosion risk and erosion risk potential were finally prepared for the study area using the Revised Universal Soil Loss Equation (RUSLE) procedure. Results indicated that destruction of the protective cover of forested areas by fire had significant effects on splash erosion and the soil erodibility factor at the micro-plot scale and also on surface erosion, erosion risk, and erosion risk potential at the watershed scale. Moreover, the results showed that correlation coefficients between different variables at the micro-plot and watershed scales were positive and significant. Finally, assessment and monitoring of the erosion maps at the regional scale showed that the central and western parts of the study area were more susceptible to erosion compared with the western regions due to more intense crop-management, greater soil erodibility, and more rainfall. The relationships between erosion parameters and the most important vegetation attributes were also used to provide models with equations that were specific to the study region. The results of this paper can be useful for better understanding erosion processes at the micro-scale and macro-scale in any region having similar vegetation attributes to the forests of northern Iran.

Feasibility of High-Resolution Soil Erosion Measurements by Means of Rainfall Simulations and SfM Photogrammetry

The silty soils of the intensively used agricultural landscape of the Saxon loess province, eastern Germany, are very prone to soil erosion, mainly caused by water erosion. Rainfall simulations, and also increasingly structure-from-motion (SfM) photogrammetry, are used as methods in soil erosion research not only to assess soil erosion by water, but also to quantify soil loss. This study aims to validate SfM photogrammetry determined soil loss estimations with rainfall simulations measurements. Rainfall simulations were performed at three agricultural sites in central Saxony. Besides the measured data runoff and soil loss by sampling (in mm), terrestrial images were taken from the plots with digital cameras before and after the rainfall simulation. Subsequently, SfM photogrammetry was used to reconstruct soil surface changes due to soil erosion in terms of high resolution digital elevation models (DEMs) for the pre- and post-event (resolution 1 × 1 mm). By multi-temporal change detection, the digital elevation model of difference (DoD) and an averaged soil loss (in mm) is received, which was compared to the soil loss by sampling. Soil loss by DoD was higher than soil loss by sampling. The method of SfM photogrammetry-determined soil loss estimations also include a comparison of three different ground control point (GCP) approaches, revealing that the most complex one delivers the most reliable soil loss by DoD. Additionally, soil bulk density changes and splash erosion beyond the plot were measured during the rainfall simulation experiments in order to separate these processes and associated surface changes from the soil loss by DoD. Furthermore, splash was negligibly small, whereas higher soil densities after the rainfall simulations indicated soil compaction. By means of calculated soil surface changes due to soil compaction, the soil loss by DoD achieved approximately the same value as the soil loss by rainfall simulation.

River hydrology and recent suspended sediment flux in the Red River: implication for assessing soil erosion and sediment transport/deposition processes

Based on a database of daily water discharge and daily suspended particulate matter concentrations along the Red River and at the outlet of the main tributaries (Da and Lo) during the 2005-2010 period, covering contrasting hydrological conditions, the water and sediment fluxes transported by the Red River system were determined. The results showed that only 21% of the discharge is derived from the upper Red River, 54% and 25% being derived from the Da and the Lo Rivers, respectively. In contrast, the distribution of suspended particulate matter (SPM) load is very different of that observed for water discharge: most SPM were eroded from the upstream catchment located in China (78%). Moreover, annual SPM fluxes (FSPM) showed a strong spatial variability between upstream watershed and the outlet of the river. The mean inter-annual FSPM was 30 Mt/yr (i.e. specific flux of 741 t/km²/yr) at the LaoCai site, 38 Mt/yr (i.e. 792 t/km²/yr) at the PhuTho gauging site, 29 Mt/yr (i.e. 193 t/km²/yr) at the SonTay gaugng station. Its values were 4.1 Mt/yr (i.e. 80 t/km²/yr) and 6.6 Mt/yr (i.e. 191 t/km²/yr) for the Da and Lo rivers, respectively. Between the LaoCai and PhuTho sites, both erosion and sedimentation processes occurred together, but strongly depended on the hydrological conditions. Between the PhuTho and SonTay sites, the important loss of SPM flux suggested a dominant deposition process in the floodplain during high water before the delta. These results proved the complex processes of erosion/sedimentation occurring on the Red River watershed.