Potential Erosion Risk Research Articles

Three-dimensional simulation of cavitating flow in reciprocating positive displacement pumps with fluid-actuated valves

Abstract An in-house compressible three-dimensional (3D) finite volume Computational Fluid Dynamics (CFD) method, with statistical turbulence model and moving grid capabilities, is presented and applied to the suction stroke of a simplex plunger positive displacement pump. The approach utilizes a pressure-based implicit solution algorithm and a mass transfer cavitation model. Fluid-actuated valve dynamics are approximated using a fluid-structure interaction algorithm. The closed valve and early phase of valve opening are approximated by a permeable wall. A circular segment model is introduced, significantly reducing computing time. Experimental validation is performed by time-resolved pressure and flow rate measurements, as well as high-speed visualizations of the valve dynamics. A speed variation is conducted to investigate harmless advanced and erosive distinctive partial cavitation. The simulation reproduces the delay of cavity collapse, observed with increasing speed, and reveals distinctive void patterns related to the chamber pressure time progression. These void patterns are fundamental for understanding the cavitation dynamics and potential erosion risk in the system. Deviations from data remain in the flow phase subsequent to the collapse due to overestimated wave reflection at the inlet boundary in the suction pipe.

Hydrological Connectivity Response of Typical Soil and Water Conservation Measures Based on SIMulated Water Erosion Model: A Case Study of Tongshuang Watershed in the Black Soil Region of Northeast China

The black soil region of Northeast China is the largest commercial grain production base in China, accounting for about 25% of the total in China. In this region, the water erosion is prominent, which seriously threatens China’s food security. It is of great significance to effectively identify the erosion-prone points for the prevention and control of soil erosion on the slope of the black soil region in Northeast China. This article takes the Tongshuang small watershed (Heilongjiang Province in China) as an example, which is dominated by hilly landforms with mainly black soil and terraces planted with corn and soybeans. Based on the 2.5 cm resolution Digital Elevation Model (DEM) reconstructed by unmanned aerial vehicles (UAVs), we explore the optimal resolution for hydrological simulation research on sloping farmland in the black soil region of Northeast China and explore the critical water depth at which erosion damage occurs in ridges on this basis. The results show that the following: (1) Compared with the 2 m resolution DEM, the interpretation accuracy of field roads, wasteland, damaged points, ridges and cultivated land at the 0.2 m resolution is increased by 4.55–27.94%, which is the best resolution in the study region. (2) When the water depth is between 0.335 and 0.359 m, there is a potential erosion risk of ridges. When the average water depth per unit length is between 0.0040 and 0.0045, the ridge is in the critical range for its breaking, and when the average water depth per unit length is less than the critical range, ridge erosion damage occurs. (3) When local erosion damage occurs, the connectivity will change abruptly, and the remarkable change in the index of connectivity (IC) can provide a reference for predicting erosion damage.

Soil erosion risk in the Mocache Canton applying multicriteria analysis and geographic information systems

Soil erosion is one of the main and most widespread types of soil degradation, determined by environmental and anthropogenic factors, which significantly impact the physical, chemical and biological properties of the soil, favoring its degradation. Consequently, through this research we sought to evaluate the risk of soil erosion in the canton of Mocache through the application of multicriteria analysis techniques and the use of geographic information systems (GIS). The CORINE model included several criteria for the zoning of potential and actual erosion risk, including erosivity, defined by the Modified Fournier Index (MFI) and the Bagnouls-Gaussen Aridity Index (BGI); erodibility, composed of soil texture, stoniness and depth; soil occupation; slope-orientation; and vegetation cover, through the estimation of the Normalized Difference Vegetation Index (NDVI). An expert consultation supported by Analytic Hierarchy Process (AHP) was applied to define the contribution of each criterion to erosion risk. The resulting layers were combined using a weighted relationship (map algebra) within the GIS environment. It was obtained that slope-orientation and erosivity explain a large part of the erosion risk, with a weighting of 42.46% and 27.48% in order, according to the expert evaluation and the AHP. The high erosivity was contributed by the predominant climatic factors: intense precipitation and high temperatures. In addition, it was found that the potentialand current erosion risk represent 13.1% (7,244 ha) and 10.7% (5,905 ha) of the territorial extension. It is concluded that physical-natural, meteorological factors and anthropogenic activities contribute to the risk of potential and current soil erosion in Mocache canton

Assessment of environmental impact of road construction based on results of remote sensing monitoring

Remote sensing detected the impact of road construction on important environmental properties. The digital elevation model was applied to assess the impact of road construction on environmental regimes. The study focused on the total area of the 3-km zone of influence (monitoring zone of probable impact) around the national road H-31 Dnipro-Tsarychanka-Kobeliaky-Reshetylivka from Loboikivka village to the boundary of Dnipropetrovsk Oblast. The following derivatives of the digital elevation model are considered as geomorpho­logical variables: the topographic wetness index (TWI) and erosion factor (LS). To model the effect of road construction on the moisture regime and dynamics of erosion processes, the TWI and LS indices were calculated for a digital terrain model without a road and with a road with an elevation that corresponds to the planned level. Thus, the road is considered as an anthropogenic landform that changes the direction of water redistribution along the topography and thus affects the potential moisture conditions and erosion risks. The modeling results indicate that the transformation of the water regime will be observed within the entire 3-km monitoring area. Deviations from the normal value can be up to 7 units by module, which is about one third of the landscape-wide range of topographic moisture index values. Almost no impact of construction can be predicted for 80.7% of the territory. For 10.6% of the territory, the increase in moisture regime will be moderate, and for 3.2% of the area the increase will be very significant. In turn, for 4.3% of the area the decrease in humidification will be moderate, and for 1.2% the decrease will be very significant. The greatest impact on the redistribution of moisture conditions is predicted in the immediate vicinity of the road. Changes in the moisture regime can have significant negative consequences for both soil cover and biotic components of ecosystems. Changes in vegetation as a consequence of changes in both moisture and trophic conditions can be considered as possible scenarios for the development of landscape cover dynamics.

Future changes in global rainfall erosivity: Insights from the precipitation changes

Quantifying future changes in rainfall erosivity is essential to address potential water erosion risks. This study reveals a significant power function relationship between rainfall erosivity and precipitation both globally and across various climatic zones. Building on this foundation, new empirical models were developed to project relative changes in rainfall erosivity. These models, predicted on the understanding that General Circulation Models (GCMs) provide more accurate predictions of climate change trends than exact meteorological values, utilizes the ratio of modeled historical precipitation to future precipitation under various scenarios as the variable, formulated as a power function. Data from three GCMs runs from both the Coupled Model Intercomparison Project phase 5 (CMIP5) and CMIP6–including historical, mid-term, and long-term periods–were employed. The analysis suggests that by the end of the 21st century, global annual rainfall erosivity could increase by 2.6% under the Shared Socio-Economic Pathway (SSP)1–2.6 scenario, by 3.5% under SSP2-4.5, and by a significant 6.4% under SSP5-8.5, relative to the 2000–2010 baseline. Furthermore, over 76% of the global land area is projected to experience an increase in rainfall erosivity over the century. Regions with projected changes in rainfall erosivity, whether increase or decrease, are likely to face more pronounced changes from mid-century onwards. The CMIP6 exhibits improved model consistency over its predecessor, CMIP5, indicating a greater water erosion risk as global warming progresses. These projections offer insights for strategies to combat soil degradation due to climate changes.

The expansion of the Atlantic–Mediterranean ghost crab Ocypode cursor (Linnaeus, 1758): Distribution, environmental niches and future perspectives

AbstractThe tufted ghost crab Ocypode cursor (Linnaeus, 1758) found in the Mediterranean Sea and the Atlantic Ocean is currently a great example that elucidates concerns within scientific and conservation communities. This species, native to the subtropical Atlantic Ocean and the warmest southeastern Mediterranean Sea (Egypt), has been extending its distribution in both regions since the 1980s, likely due to the warming sea temperatures. These small nocturn crabs are typically found inhabiting sandy beaches and dune environments. This species is an opportunistic predator eating terrestrial and marine prey, especially on sea turtle eggs. Despite its status as a threatened species by two European conventions, there is a lack of knowledge of its ecology and biology. Sometimes considered as an indicator of good ecological status of beaches where it lives, this ghost crab could nevertheless benefit from climate change to extend its distribution range. This review aims to create a baseline on the current knowledge and gaps in the published scientific literature on the ghost crab. Additionally, through an analysis of the existing literature, we also offer insights into the potential risk of beach erosion associated with the expansion of this species.

MODELAGEM PREDITIVA APLICADA AO MAPEAMENTO DE RISCO POTENCIAL DE EROSÃO DE SOLOS NA AMAZÔNIA OCIDENTAL

The modeling of areas susceptible to soil loss due to hydro-erosive processes consists of methods that simplify reality to predict future behavior based on the observation and interaction of a set of geoenvironmental factors. Thus, the objective of the current analysis is to predict susceptibility to soil loss and map areas with the potential risk of erosion using the principles of Binary Logistic Regression (BLR) and Artificial Neural Networks (ANN). The hydrographic sub-basin of the Sete Voltas River (330 km2), Rondônia, Brazil, was defined as the experimental area. Models were obtained using 100 sample units and 14 predictor parameters. Susceptibility was mapped based on five reference classes: very low, low, moderate, high, and very high. ANN obtained an area under the curve (AUC) of 0.808 and global precision of 79.2%, and the BLR model showed an AUC of 0.888 and global precision of 77%. Potentially susceptible areas represent 57.71% and 54.80% of the area for BLR and ANN models, respectively. The greatest potential risks are verified in places with no vegetation cover associated with agricultural practices. The technique proved to be effective, with adequate precision and the advantage of being less time-consuming and expensive than other methods. Keywords: Binary Logistic Regression; Artificial Neural Network; Erosion Susceptibility.

Erosion Hazards in the Tayan Sub-Watershed, West Borneo Province

This research focuses on predicting erosion in the Tayan Sub Watershed, a part of the Kapuas Watershed in the Tayan Hilir District, Sanggau Regency, West Borneo Province. Watersheds play a crucial role in providing quality water, and land changes can lead to watershed damage, particularly concerning erosion. This research utilizes the Universal Soil Loss Equation (USLE) model combined with Geographic Information System (GIS) to predict the distribution of erosion hazard in Sub DAS Tayan. Parameters analyzed in this research include rainfall factors, soil erodibility, slope steepness, and land cover. The results indicate that erosion hazard classes in Sub-DAS Tayan range from low to high. Although most soils have low erodibility, the presence of areas with high erodibility suggests potential erosion risks that need attention. The majority of slopes fall into the flat to moderately steep categories, coupled with the dominance of secondary forest land cover, indicating an environmentally risky condition for future erosion occurrence. This research is expected to assist decision-making regarding soil and water conservation actions in Tayan Sub Watershed.

Soil Erosion Risk Assessment in The Niğde Using Corine Model

Soil erosion risk was calculated using the coordination of information on the environment (CORINE) model in this study. The aim of the study is to determine the soil erosion risk of Niğde province, taking into account soil properties, slope and land use. Potential (PSER) and actual soil erosion risks (ASER) were determined using factors which were soil properties, slope, climatic factors, and land cover data. Data were produced using Arc-GIS 10.3 software, and results were obtained on these maps. 34.72% of the soils were classified as moderately actual soil erosion risk, which located in the eastern and southeast part of the study area.51.66% and 13.62% of the soils were classified as low and high actual soil erosion risk, respectively. Areas which have low actual soil erosion risk are located in the middle part, and areas which have high actual soil erosion risk are located in the northwest part of the area. The areas which were categorized as low potential soil erosion risk were increased from 23.52% to 51.66% in the actual soil erosion risk, after combining the land cover map. On the other hand, the total areas classified as high and moderate actual soil erosion risk decreased from 76.48% to 48.34% in the actual soil erosion risk due to land cover types. Soil texture, land cover, and slope are the most important factors that affect erosion risk. This study indicated that the CORINE model integrated with GIS (Geographic Information Systems) and RS (Revised Universal Soil Loss Equation) has a very effective and accurate potential for soil erosion risk assessment.

Identification of Eroded and Erosion Risk Areas Using Remote Sensing and GIS in the Quebrada Seca watershed

The aim of this research was to identify eroded areas and areas at risk of erosion (EAER) as indicators of soil degradation by water erosion in a semiarid watershed of the Venezuelan Andes in 2017. To this effect, remote sensing techniques and geographic information systems (GIS) were used, focusing on spectral reflectance data from a satellite image, given the absence of continuous pluviographic information and data on soil properties in developing countries. This methodology involved estimating the potential water erosion risk (PWER) and mapping eroded and erosion risk areas (EAER) based on calculating the spectral Euclidean distance to bare soils and a remote sensing technique, which was selected via linear regression. Receiver operating characteristics (ROC) curves were determined to define classification thresholds, which were validated by means of a supervised classification and associated to PWER values. The main results indicate that EAER1 identified more eroded areas with bare soils (229,77 ha) as opposed to EAER2 (195,57 ha). Similarly, it was evident that the first alternative was more successful that the second (sum of the first three principal components). The PWER analysis, in addition to the erosion mapping developed and other data and criteria, such as mini-mum area size of interest, could help to consider necessary soil conservation measures.

Assessing the Impact of Engineering Measures and Vegetation Restoration on Soil Erosion: A Case Study in Osmancık, Türkiye

The prioritization of preventing soil loss in Türkiye’s watersheds has become a pressing concern for planners. Numerous mathematical models are presently utilized on a global scale for soil erosion prediction. One such model is the Revised Universal Soil Loss Equation (RUSLE), commonly used to estimate average soil loss. Recently, there has been an increased emphasis on utilizing USLE/RUSLE in conjunction with Geographic Information System (GIS) technology, enabling grid-based analysis for predicting soil erosion and facilitating control measures. This study evaluates the effectiveness of erosion and flood control initiatives started in the 1970s within the Emine Creek watershed and its tributary rivers in Osmancık, Türkiye, utilizing RUSLE/GIS technologies. Two distinct maps illustrating the potential erosion risks were produced for two distinct temporal intervals, and a comparative analysis was conducted to evaluate the alterations that transpired. The implementation of various measures such as terracing, afforestation, and rehabilitation in the watershed led to a notable prediction of decreasing soil loss in the watershed. From 1970 to 2020, the rate of estimated soil loss was reduced from 417 to 256 metric tons per hectare per year, demonstrating the effectiveness of soil conservation measures in a semi-arid and weakly vegetated area at reducing potential soil loss.

Numerical assessment of cavitation erosion risk on the Delft twisted hydrofoil using a hybrid Eulerian-Lagrangian strategy

Cavitation damage is a major threat to the life span of fluid machinery and has been a hot research issue in engineering for a long time. The current work aims to show the ability to assess cavitation erosion risk on the twisted hydrofoil using a hybrid Eulerian-Lagrangian solver. The volume of fluid method is used for the liquid-vapor interface of resolved vapor structures, while the discrete bubble model is utilized to track micro-scale unresolvable bubbles. A two-way coupling approach is introduced to enable the transition between resolved cavities and bubbles based on their volume, relative location, and shape. A Lagrangian erosion model considering the effect of asymmetric bubble collapse is proposed to predict cavitation erosion risk. Compared with the experimental result, the current model can accurately identify the high erosion risk regions on the hydrofoil surface. The distribution and intensity of the high impact pressures emitted from bubbles is quantitatively evaluated. In addition, the erosion sensitive zones at different stages of the one cloud cavitation cycle are determined and the hydrodynamic mechanisms of aggressive collapse events are analyzed in detail. The results reveal that the potential erosion risk is highest in areas where primary shedding occurs, which causes the macroscopic cavity to roll up. Bubbles with high impact pressures are mainly focused around the edges of the shedding cavity. The secondary shedding contributes to erosive structure in a limited middle angle of attack area, such that when the primary shedding U-shaped structure evolves and begins to collapse, it becomes less erosive, and only isolated points of erosion is found. Further investigation demonstrates that this is due to a transformation from U-shaped vortex to O-shaped vortex, moving the bubbles gradually away from the hydrofoil surface, thereby reducing the cavitation erosion risk.

Pemetaan Tingkat Bahaya Erosi dengan Pemanfaatan Teknologi Drone di DTA Cipaheut Sub DAS Cikapundung Hulu

Technology in the field of mapping is constantly evolving to provide convenience for human work. One of the innovations that are developing in today’s modern era is drone or Unmanned Aerial Vehicle (UAV). Erosion mapping and erosion measurements are carried out to determine the potential risk of erosion in certain areas. The erosion risk map shows the distribution of erosion hazard levels in an area. The objective of this research is to determine erosion prediction and erosion hazard levels spatially based on USLE (Universal Soil Loss Equation) method using drone. The used of UAV for collecting data to generate soil erosion risk map at detail scale based on USLE method is relatively infrequently done in Indonesia. The research was conducted in Cipaheut Watershed, Cikapundung Hulu Sub-watershed, Cimenyan, Cimenyan, Bandung Regency, West Java. The results of the study show that the role of drone is very helpful in mapping general conditions and land use spatially. In addition, drones are able to provide actual data sources to identify the physical factors needed in the USLE method of erosion calculations such as LS, C and P factors. Erosion prediction and erosion hazard levels can be calculated using data acquired from drones. There are 8 SPLs with a total land area of ​​225.10 Ha. SPL 5 with the use of dry land and steep slope have the highest erosion prediction values ​​of 703.1207 tons/ha/year and an erosion hazard index of 87.8901 tons/ha/year with a very high level of erosion hazard.

Spatiotemporal variability of the potential wind erosion risk in Southern Africa between 2005 and 2019

AbstractRegional assessments of the wind erosion risk are rare and vary due to the methods used and the available data to be included. The adaptation of existing methods has the advantage that the results can be compared directly. We adopted an already successfully applied methodology (ILSWE—applied in East Africa), to investigate the spatiotemporal variability of the wind erosion risk between 2005 and 2019 in Southern Africa. The approach integrates climatic variables, a vegetation index, and soil properties to describe the potential impact of wind erosion at the landscape scale. The annual and seasonal variability is determined by the vegetation cover, whereas droughts and strong El Niño events had only regional effects. We estimated that 8.3% of the study area experiences a moderate to elevated wind erosion risk over the 15‐year period with annual and inter‐annual fluctuations showing a slight upward trend. In general, the desert and drylands in the west have the highest proportion of risk areas, the moist forests in the east are characterized by a very low risk of wind erosion, while the grasslands, shrublands, and croplands in the interior most likely react to changes of climatic conditions. The validation process is based on a comparison with the estimated frequency of dust storms derived from the aerosol optical depth and angstrom exponent and revealed an overall accuracy of 65%. The results of this study identify regions and yearly periods prone to wind erosion to prioritize for further analysis and conservation policies for mitigation and adaptation strategies.

Soil erosion risk under climate change scenarios: A case study in rural area with varying land uses

Soil erosion is one of the major issues in the tropics. The erosion is highly affected by the changes in climate and land cover. Future changes in tropical climate, particularly precipitation are expected to influence the potential risks of soil erosion. In the face of rapid changes in rural land cover for agricultural purposes, the combined forcings of land cover and climate changes have been to be a major threat to the soil conservation due to soil erosion. In this study, climate change scenarios at the northern part of Borneo were developed based on the RCP 4.5 and RCP 8.5 climate scenarios using Weather Research Forecast Model (WRF). The future climate projection scenarios of the total precipitation were used to simulate the potential erosion risks in varying land covers in a rural area of Sabah, Malaysia. The RUSLE model was used for soil erosion modelling, which was integrated with IDRISI Selva that allow the analysis and assessment of erosion risk. The variability of future total precipitations in the area of varying land cover types have resulted in varying degree of potential soil erosion risk The average soil loss at the studied area has increased by 262 t/ha/yr with 35.94 % increment in annual precipitation under RCP 8.5 emission scenario. However, under RCP 4.5, 26.65 % decrement in precipitation has reduced the soil loss by 315.1 t/ha/yr. In this rural area, exceptionally high soil erosion was found at steep slopes and thin vegetation covers. Therefore, an appropriate land use planning, soil conservation practices, and strategic adaptation options plan should be created and developed to ensure the sustainability of the soil conservation and enhance rural agricultural productivity.

Assessment of potential maximum erosion and sediment disaster risk of typhoon events

Assessment of potential maximum erosion and sediment disaster risk of typhoon events

Mapping potential erosion risk in Bendimahi sub-basin using CORINE and ICONA models

Erozyon, günümüzde ülkemizin maruz kaldığı en önemli çevresel risklerden birisidir. Bulunduğumuz coğrafyadaki topografik çeşitlilik, toprak çeşitliliği, yağış rejimindeki değişiklikler, çeşitli erozyon risk derecelerinin oluşmasına neden olmaktadır. Bu çalışmada, ülkemizdeki birkaç kapalı havzadan birisi olan Van Gölü Havzası içerisinde yer alan Bendimahi alt havzasındaki erozyon riski, iki farklı risk değerlendirme yöntemi kullanılarak belirlenmiş ve yöntemlerin birbirleriyle karşılaştırılması amaçlanmıştır. Bu kapsamda, erozyon risk derecelendirilmesinde en çok kullanılan tekniklerden olan Institute for the Conservation of the Nature (ICONA) ve The Coordination of Information on the Environment (CORINE) risk değerlendirme sistemleri kullanılmıştır. Bu çerçevede, kullanılan tekniğe göre toprak özellikleri, yağış, bitki kapalılığı, eğim, kuraklık ve litojik yapı gibi erozyona doğrudan etki eden veriler kullanılmıştır. Sonuçlar saha çalışmalarından elde edilen yüksek düzeyde erozyona maruz kalmış 18 alanla doğrulanmıştır. Buna göre; ICONA ve CORINE risk derecelendirme tekniklerinin doğruluk oranları %50 olarak saptanmıştır. Ancak çapraz doğrulama yapıldığında bu oran %33 olmuştur. Dolayısıyla, her ne kadar iki yöntemin doğrulukları aynı olsa da birbirleriyle uyumlarının sınırlı düzeyde olduğu belirlenmiştir. Ayrıca, ICONA modelinin daha az girdi verisiyle aynı doğrulukta sonuç üretebilmesinden dolayı küçük havzalar için daha verimli bir yöntem olduğu belirlenmiştir.

Predicting Shoreline Change for the Agadir and Taghazout Coasts (Morocco)

Aangri, A.; Hakkou, M.; Krien, Y., and Benmohammadi, A., 2022. Predicting shoreline change for the Agadir and Taghazout coasts (Morocco). Journal of Coastal Research, 38(5), 937–950. Coconut Creek (Florida), ISSN 0749-0208. Prediction of the long-term shoreline change under the effect of natural and anthropogenic factors is a fundamental goal for coastal managers. This paper presents a simple model for predicting the shoreline change for the Agadir and Taghazout coasts, which consist of several sandy beaches, in the horizons 2050 and 2100; this coastal area plays a vital economic role in this region. The anticipation of its protection against erosion is necessary in view of the effects of climate change, and it will preserve its potential for tourism and urban development in the long term through the establishment of the construction setback line. The approach proposed here combines the long-term extrapolations of historical shoreline changes (1969–2020) in the future, and the estimate of the shoreline retreat due to sea level rise (SLR) by using Bruun's rule, using the severe RCP 8.5 scenario, and taking into account the contribution of vertical land movements. The model used has been calibrated through incorporating a correction factor (F), calculated by comparing observed and predicted data over a long period. The analysis of the predictions results provided in this work showing a potential risk of erosion threatening all seaside tourist and urban infrastructures along this coast. The average retreat is estimated at 12 m by 2050 and 51 m by 2100.

Numerical prediction of cavitation erosion risk in an axisymmetric nozzle using a multi-scale approach

In the present study, a two-way coupling Eulerian–Lagrangian approach is developed to assess the cavitation erosion risk in an axisymmetric nozzle. Macroscopic cavitation structures are simulated using the large eddy simulation along with the volume of fluid method. The compressible Rayleigh–Plesset equation and the bubble motion equation are introduced to resolve the microscopic bubble dynamics. The calculated results agree favorably with the experimental data and can capture more flow details, which is associated with the potential erosion risk. Based on the bubble information in multi-scale cavitating flow, a new asymmetric bubble collapse model is proposed to calculate the impact pressure, which is then used to quantitatively assess the cavitation erosion risk in the nozzle. The results show that, compared with the traditional Euler method, the location and value of the potential maximum cavitation erosion risk predicted by this new method are closer to the experimental measurement. The advantages of the newly proposed method are further elaborated systematically. The study found that the high environmental pressure triggered by the collapse of shedding clouds can cause the near-wall bubbles to shrink and even collapse, releasing impulsive pressure, which directly damages the material surface. This phenomenon is considered to be closer to the actual cavitation erosion process. Finally, analyzing the relationship between multi-scale cavitation structures and erosion risk reveals that the high risk of cavitation erosion is mainly due to the oscillation and collapse of near-wall bubbles which are generated near the attached cavity closure line or surrounding the shedding clouds.

QUANTITATIFICATION OF SOIL EROSION USING CAUSATIVE FACTORS IN THE GIS ENVIRONMENT FOR SYLHET DISTRICT, BANGLADESH

The aim of this study was to enumerate the potential soil erosion in the Sylhet district of Bangladesh using the Revised Universal Soil Loss Equation (RUSLE) approach in the software-based windows. Using the rainfall erosivity factor (R), the soil erodibility factor (K), the cover management factor (C), the topographic factor (LS) and the support practices factor (P), the RUSLE formula quantified the possible soil loss rate. The soil erosion rate was classified into six classes based on the erosion severity. The result shows that the annual soil deterioration rate differs from 0 to 799.67 t/ha/year. However, almost about 97.71% of the total surface area is under low potential (54.1%) and moderate (43.61%) erosion risk. Rather about 2.29% area of Sylhet district was under average, high, very high and critic erosion risk. Result indicates that the north-eastern and central zone are highly vulnerable to soil erosion due to steep slope and P factor.