Search

The large-scale management of ditches and implementation of land projects in loess areas have increased the arable land area but have caused considerable engineering issues, resulting in severe soil erosion. In this study, field tests were performed at different time scales, a control group was established, organic material–plant joint restoration technology was proposed as an optimized management measure, and the erosion control mechanism and restoration mode of organic material–plant joint restoration technology were analyzed. Based on the obtained experimental data, a Water Erosion Prediction Project (WEPP)-based hydraulic erosion model was constructed, sensitivity parameters were calibrated, and the soil erosion intensity and corresponding spatial distribution in the watershed of the study area were simulated via the geo-spatial interface for WEPP (GeoWEPP) after organic material–plant joint restoration technology was adopted to predict the effect of optimized management measures. The results showed that among the slopes with different restoration measures, organic material–plant joint restoration technology effectively controlled loess slope erosion, and the average erosion modulus of the organic material–grass and shrub transplantation slope reached only 23.37 t/km2, which is a decrease of 97.68% relative to the traditional grass–shrub protection slope. Moreover, the sand content of the joint restoration slope was reduced by 392.41 g/L relative to the bare slope, reaching only 0.29 g/L, and the runoff yield was reduced by 8.88 L/min. The GeoWEPP modeling results revealed that the total runoff yield and average annual erosion modulus of the watershed were lower after joint restoration than during the prerestoration period. Similarly, the total runoff yield of the watershed was 4.6%, the simulated 10-year average annual total sand production reached 2048.3 t, and the average annual erosion modulus was 582.75 t/km2, which is 52.15% lower than that under untreated conditions. This study provides a new strategy for solving soil erosion problems and restoring the ecology of slopes after managing ditches and implementing land projects. [ABSTRACT FROM AUTHOR]

The throttle valve is vital in the oil and gas production stage, designed to decrease natural gas pressure at the wellhead to match transportation pipeline standards. During this process, its flow rate sharply increases, leading to erosion by sand particles discharged from the well's bottom. To predict the cage throttle valve's service life, we established and validated an erosion model for its throttling trim through tests, calculating the erosion wear rate using CFD simulation software. Tests reveal that WC–Co cemented carbide displays typical brittle material traits; its highest erosion wear rate occurs at a 90° impact angle, with a velocity index of 2.4. Study findings indicate the most severe erosion at the smallest orifice of the cage, with the erosion wear rate increasing linearly as particle mass flow rate rises. Consequently, the throttle trim should be inspected and replaced within two years for low mass flow rates of sand particles, or within 3 to 6 months for high mass flow rates. [ABSTRACT FROM AUTHOR]

Erosion equations were developed to predict the material removal of polyurethane coatings on carbon fiber reinforced plastic (CFRP) surfaces and validated through experimental data. The effects of abrasive properties, process parameters, and organic coating properties (such as fracture toughness and hardness) were considered in the equations. As the erosion angle increased, elastoplastic deformation in the oblique direction and repeated "deformation" in the normal direction were the main reasons for material removal. The ductile erosion behavior was confirmed by experimental data because the maximum erosion rate occurred at an incident angle of 30°. The coefficient and index in the equations were determined by experimental data, and the equations were verified. The developed equations could accurately predict the quantity loss of organic coatings under different particle sizes and particle velocities, and the erosion equations were in good agreement with the experimental data. [ABSTRACT FROM AUTHOR]

Soil, one of the non-renewable resources on this planet, is being depleted at an alarming rate due to various anthropogenic activities. The effect of soil erosion could range from on-site ecosystem fragmentation to off-site reservoir storage capacity loss. Though soil erosion is caused by various agents such as wind, water, etc., water erosion is the major type. Heavy rainfall during the monsoons and the relatively thin cover of soil over the bedrock aggravates the damage potential of this form of erosion in the state of Kerala, India. Water-induced soil erosion in the Bharathapuzha river basin in Kerala, which is blessed with cultivable land resources and intensive agricultural activities, has been undertaken for quite long and has started impacting agricultural activities, drinking water supply, and reservoir storage capacity in the basin. In this background, this study was taken up to assess the effects of climate and land use–land cover dynamics on soil erosion in the Bharathapuzha river basin over the last three decades. Soil erosion from the river basin was estimated by the Revised Universal Soil Loss Equation (RUSLE), and these estimates were verified with the observed sediment load in the Bharathapuzha river at the Kumbidi river gauging station. The storage capacity loss of some of the reservoirs located in the river basin, estimated by the Integrated Bathymetric Survey (IBS), was compared with the likely storage capacity loss of these reservoirs estimated based on soil erosion from the catchment areas upstream. Soil loss from the river basin for a future period was predicted using projections of future climate under two Representative Concentration Pathways (RCP 4.5 and RCP 8.5) from four regional climate data experiments and future land use–land cover. Annual soil loss estimation maps for 2020 and 2035 under RCP4.5 and RCP8.5 reveal the urgent necessity to plan and implement soil conservation measures in the erosion hotspots, especially in the Malampuzha, Anamala, and Attapady sub-basins. [ABSTRACT FROM AUTHOR]

The conversion of native forest to the tea plantation and cropland has intensified throughout the Coonoor watershed of the Nilgiris region over the past few decades. The current study investigates the severity of land cover changes including deforestation activities in the Coonoor watershed region as a result of urbanization, along with the establishment of recreational parks, resorts and tea plantations. In order to analyse the changes, a widely used soil erosion model say Revised Universal Soil Loss Equation (RUSLE) is opted to estimate the average soil loss. Therefore, this work marks the impact of land-use changes on land degradation and the consequent vital natural phenomenon like soil erosion. The change detection was carried out for over 14 years period from 2005 to 2018. Landsat images of corresponding years were classified using the supervised classification technique. The C-factor (cover and management factor) for the corresponding periods were also identified. Conversion of forest land into tea plantations, wastelands and settlements significantly decrease the soil organic matter (SOM) and hydraulic conductivity (HC) of the soil, which leads to a difference in the K-factor (soil erodibility factor) throughout the study period, whereas the R-factor (rainfall and runoff factor) and LS-factor (length-slope factor) were considered to be constant throughout the period. Results indicate the annual soil loss during the period from 2000 to 2018 on each land use/cover classes. viz., tea plantations, 223.26 km2; settlement, 163.35 km2; open forest, 799.02 km2; dense forest, 1158.48 km2; and barren land, 27.18 km2. The total sediment yield in the study area was found to have oddly increased due to the land use/cover changes. The significant rise of soil erosion was found evitable in the deforested region which was converted to infrastructure and wasteland. [ABSTRACT FROM AUTHOR]

Soil erosion is sensitive to climate change, especially in high mountain areas. The Tibetan Plateau has experienced dramatic land surface environment changes under the impact of climate change during the last decades. In this study, we focused on the mid-Yarlung Tsangpo River (MYZ River) located in the southern part of the Tibetan Plateau. The revised universal soil loss equation (RUSLE) was applied to assess soil erosion risk. To increase its applicability to high mountain areas with longer periods of snowfall, snowmelt runoff erosivity was considered in addition to rainfall erosivity. Results revealed that soil erosion of the MYZ River region was of a moderate grade with an average soil erosion rate of 29.1 t ha−1 year−1 and most serious erosion in wet and cold years. Soil erosion rate in the MYZ River region showed a decreasing trend of − 1.14% year−1 due to the precipitation, temperature, and vegetation changes from 2001 to 2015, with decreasing precipitation being the most important factor. Increasing precipitation and temperature would lead to increasing soil erosion risk in ~ 2050 based on the Coupled Model Intercomparison Project (CMIP5) and RUSLE models. It is clear that soil erosion in high mountain areas greatly depends on climate state and attentions should be paid to address soil erosion problem in the future. [ABSTRACT FROM AUTHOR]

Erosion damage is one of the main factors leading to failure of pipeline in oil field, especially for sudden contraction section under solid-liquid two-phase flow in hydraulic fracturing. In this article, a laboratory experiment was carried out to analyze the effects of pipe flow velocity, particle concentration and pipe inner diameter ratio on particle erosion of the reducing wall in high-viscosity liquid. The results show that the erosion rate and erosion distribution are different not only in radial direction but also in circumferential direction of the sample. The upper part of sample always has a minimum erosion rate and erosion area. Besides, the erosion rate of reducing wall is most affected by fluid flow velocity, and the erosion area is most sensitive to the change in the diameter ratio. Meanwhile, the erosion rate of reducing wall in cross-linked fracturing fluid is mainly determined by the fluid flowing state due to the high viscosity of the liquid. In general, the increase in flow velocity and diameter ratio not only causes the expansion of erosion-affected flow region in sudden contraction section, but also leads to more particles impact the wall. [ABSTRACT FROM AUTHOR]

Soil erodibility (K), which has important influences on the accuracy of soil loss prediction, is a critical factor in the universal soil loss equation (USLE) and the models modified from it. As an effective tool to estimate soil loss, USLE has been widely applied in the US and around the world. Since the 1980s, the USLE framework for soil erosion prediction and assessment has been adopted in China. During its application in China, it has been noticed that the K values appear to be considerably lower than those in the US. This fact means that the estimated values of soil erodibility from existing methods, such as the nomograph-based database in the US, might be unreliable for their application in China and other areas. In this study, the K values for the main agricultural soils in China with those in the US were systematically compared based on the database from field runoff plots. Possible reasons for the differences were analyzed, and the reliability of soil erodibility estimation in areas outside the US was assessed. Results show that the average K factor for soils in the US is two to three times greater than that in China. For two typical stations with similar soil types located in the US and China, soil loss per rainfall erosivity is higher in the US than in China, although erosivity for the given rainfall in the US is sometimes smaller than that in China. There might be a great bias in soil loss prediction in China if the K value formulas derived from the database of the United States are used directly. This implies that the erodibility estimation formula currently used in the USLE model may need to be verified and revised. [ABSTRACT FROM AUTHOR]

Soil erosion by water is a serious problem in southern Italy, particularly in Sicily which is one of the Italian administrative regions prone to desertification. Soil erosion not only affects soil quality, in terms of agricultural productivity, but also reduces the availability of water in reservoirs. This study was conducted in the Comunelli catchment in south-central Sicily, to predict potential annual soil loss using the revised universal soil loss equation (RUSLE) and to test the reliability of this methodology to predict reservoirs siltation. The RUSLE factors were calculated for the catchment using survey data and rain gauge measurement data. The R-factor was calculated from daily, monthly and annual precipitation data. The K-factor was calculated from soil samples collected in May and November 2004. The LS topographic factor was calculated from a 20 m digital elevation model. The C- and P-factors, in absence of detailed data, were set to 1. The results were compared with those obtained from another soil loss estimation method based on 137Cs and with the soil loss estimated from the sediment volume stored in the Comunelli reservoir between 1968 and 2004. [ABSTRACT FROM AUTHOR]