Erosion Hazard Research Articles

Effects of Post-Fire Mulching with Loranthus europaeus Jacq. on Surface Runoff and Rainsplash Erosion in a Semi-Arid Pine Forest

To avoid flooding and erosion hazards, post-fire management actions are essential in Mediterranean forests after severe wildfires. In this regard, mulching is the most common action but some mulch materials, such as straw, may lead to adverse impacts in burned forests. The use of yellow mistletoe fruits (Loranthus europaeus Jacq., hereafter “LE”) for the production of biodegradable mulch and its effectiveness in post-fire hydrology have never been studied. To fill this gap, this study has evaluated surface runoff and rainsplash erosion in a pine forest in Central Eastern Spain burned by a wildfire and mulched by a mixture of LE fruits and straw (with or without adding clay particles) using a portable rainfall simulator. Compared to untreated sites, runoff increased in burned and mulched soils (by 13.6% for the mixture without clay and by 17.2% when clay was added, in the latter case significantly). This increase was mainly due to the compact layer created by mulch application on the soil surface. However, the peak flow and the time to peak were lower in mulched soils (on average by 32.7% and 60.5%, significantly only for the mulch mixture without clay), thus indicating that, in these soils, peak runoff takes longer and its maximum value is lower compared to untreated sites. Soil erosion noticeably and significantly decreased (up to 97%) in mulched areas in comparison to untreated sites without significant differences between the two mixtures. Overall, this study indicates to land managers that soil mulching with a mixture of Loranthus europaeus Jacq. and straw is an effective post-fire management action to reduce the soil erosion risk after a wildfire.

Assessment of Soil Erosion Hazards in Kambiti Subcatchment, Murang’a County, Kenya

Erosion is a global problem that destroys soil and adversely affects ecosystem productivity. Soil erosion generally involves many processes but the major activities involve particles being transported and deposited to another location. With an increasing population, soil erosion, water availability, energy production, and biodiversity loss are some of the most pressing environmental problems around the world. Erosion is a hazard associated with agriculture in tropical and semi-arid areas. Kambiti sub catchment is part of the upper Tana catchment. The upper Tana catchment includes 25% of Kenya gazette forest. A large area of land has been degraded, resulting in a drastic reduction in surface water availability during the dry season and poor-quality water during the wet season caused by high silt levels. The main objective of the study is to assess erosion hazards using RUSLE model in Kambiti sub catchment area, Murang’a County. The specific objectives of the study were to determine the effect of rainfall erosivity and soil erodibility factor in Kambiti Sub catchment area in Murang’a County, to determine effect of slope factor to soil loss in Kambiti Sub-catchment area in Murang’a County, to determine the effect of crop protection and management factor in Kambiti Sub catchment area in Murang’a County to soil loss and to determine the strategies for management of soil and water in Kambiti Sub catchment area in Murang’a County. Data was collected from the catchment and analyzed using arc Geographical Information System to obtain the specific parameters in the revised universal soil loss equation model. Interpolation method was used to determine the mean annual precipitation. The k factor is a function of soil texture. Shape file for geological structure for Kenya was obtained from Kenya Agriculture and livestock Research Organisation and analyzed by use of arc GIS to obtain soil erodibility factor. The slope factor was analyzed using digital elevation model from arc view. Digital elevation model was gotten from STRM download. The C factor was derived from Landsat imagery from sentinel of 30metres by 30 metres. It was further analysed by unsupervised classification from Arc GIS. The sentinel clip of Kambiti sub-catchment was joined with ground trothing observations. The results were useful in estimation of soil loss therefore profiling the areas prone to soil loss. Study findings indicated rain drop impact and runoff were primarily responsible for causing erosion in Kambiti sub catchment. Anthropogenic factors played an important role in amplifying the severity of the damage, such as persistent vegetative degradation and destruction of soil structure due to organic matter depletion and routine shallow tillage. In recent years, erosion control has been hampered by the occurrence of gaps in knowledge regarding the integrated nature of erosion processes, leading to land damage caused by rill and inter-rill erosion going unaddressed. Poor people and those lacking capital to invest in reclaiming land are the main causes of abandoning degraded land. Through strategic awareness campaigns and education, soil erosion will be assessed and the knowledge gap will be closed. Participation of farmers in land use decisions is inevitable as it ensures that people who utilize land resources are recognized as equal partners in identifying problems and designing solutions. It was also recommended that Identification and operationalization of alternative off-farm income.

Erosion Hazard Levels in Padang Batung Sub-district, Hulu Sungai Selatan Regency, South Kalimantan Province, Indonesia

Erosion is a form of damage to the soil caused by changes in land function on certain plains without management. The Padang Batung Sub-district area experienced land damage which was characterized by the distribution of critical land area reaching half of the area. The purpose of this study is to analyze the level of erosion hazards that occur in Padang Batung Sub-district. This study used a terrain unit map as the basis for the sample analysis unit. The number of samples in this study was 20 samples using the purposive random sampling method. The data analysis used is in the form of the Universal Soil Loss Equation (USLE) equation which can predict the level of erosion hazard through several parameters in the study area. The results showed that the erosion hazard level in Padang Batung Sub-district was dominated by severe criteria with an affected area of 74 km2 with an average erosion rate of 345.27 tons/ha/yr. One of the dominating factors causing the high erosion in Padang Batung Sub-district to be included in the medium and high classification is rain intensity, high erodibility, unstable topography and land cover vegetation.

Monthly to seasonal rainfall erosivity over Italy: Current assessment by empirical model and future projections by EURO-CORDEX ensemble

The estimation of rainfall erosivity in the Revised Universal Soil Loss Equation (RUSLE) requires long series of sub-hourly rainfall observations. Due to the endemic unavailability of this information, at least with the required degree of detail and coverage, empirical models are frequently used for the estimation of rainfall erosivity basing on easily retrievable rainfall values at the monthly or annual scale. In this paper, an empirical model is calibrated for Italy to bridge the annual to monthly scale gap by means of 10-year series of monthly rainfall observations at 171 Italian rain gauges, and then applied using the ERA5-Land gridded rainfall dataset to obtain maps of monthly and seasonal rainfall erosivity covering the reference period 1981–2010. Successively, 29 EURO-CORDEX bias-corrected rainfall projections for two future horizons (2021–2050 and 2051–2080 under RCP 2.6, 4.5 and 8.5) are used to obtain expected anomalies of seasonal rainfall erosivity over Italy with respect to the reference period. Statistical and visual analysis of results shows that positive percentage anomalies are expected in large portions of the country, especially under RCP 2.6 but with significant increases expected also under RCPs 4.5 and 8.5, especially in autumn and, secondarily, in summer. This intra-annual rainfall erosivity anomaly pattern entails the existence of increasing trends in the erosion hazard that cannot be captured by empirical models only relying on annual rainfall. The position of those results in the related literature is deeply discussed, providing significant insights on uncertainty sources and possible future research developments.

Nature as a solution for shoreline protection against coastal risks associated with ongoing sea-level rise

The risks from climate change are ever-growing, especially in more vulnerable and exposed regions such as coastlines. The rise in sea level and increase in the frequency and intensity of climate-induced coastal hazards are threatening the increasing coastal populations. Brazil, with its 8,500 km of coast, is one of the countries most at risk from coastal flooding and erosion. Nature-based solutions have been suggested as climate adaptation strategies with the greatest potential to counteract coastal hazards stemming from sea-level rise and safeguard coastal cities. However, there is still a knowledge gap in the scientific literature on the effectiveness of nature-based solutions, especially at large spatial scales in Central and South America. Here, we assessed the risks from climate-induced hazards of coastal erosion and flooding related to sea-level rise on the Brazilian coast, and the effectiveness of nature-based solutions as climate adaptation strategies. We reveal that nature-based shoreline protection can reduce by 2.5 times the risks to the Brazilian coastline. The loss of existing natural habitats would substantially increase the area and population at risk from these climate-induced hazards. Worrisomely, legal mechanisms to protect these natural habitats are few and being weakened. Only 10% of the coastal natural habitats are within protected areas, and these alone do not ensure coastal protection, as our results indicate that the loss of unprotected natural habitats has about the same risk as the total absence of natural habitats. Our results warn of the severe consequences of the continued loss of natural habitats along the coast. Thus, actions towards the maintenance and protection of coastal habitats are paramount for climate adaptation and to ensure the well-being and livelihoods of coastal populations. Brazil has a central role in demonstrating the benefits of strategies based on nature-based solutions for shoreline protection, favoring their implementation worldwide. We provide both the natural habitat maps and the maps with model results with spatial and numerical information so readers can explore the relations between the natural habitats and coastal risk indexes at a sub-national level and foster their use by local stakeholders.

Determination of Land Suitability Criteria for Maize Hybrid in Boalemo Regency Based on Optimum Yield and Selected Land Quality

The significant effect of land quality on maize production has not been fully considered in the existing land suitability criteria. Therefore, this study aims to determine land suitability criteria for hybrid maize in Boalemo Regency based on the optimum yield and land quality. It was carried out in Boalemo Regency, Indonesia, where the land unit of 67 units was surveyed to obtain land characteristics data. A partial least square of structural equation model (PLS-SEM) with SmartPLS 8.0 was used to select a robust land quality controlling hybrid maize yield, while the boundary line method was used to determine optimum yield and differentiating of land suitability criteria. The result showed that land qualities that define the optimum yield of hybrid maize were root conditions, nutrient availability, nutrient retentions, land preparation, and erosion hazard. The soil characteristics were effective depth, coarse material, organic C, total N, K exchangeable, slopes, soil erosion, rock outcrops, and surface rocks. Furthermore, the highest optimum yield of 8.54 ton/ha was achieved by the total N and slopes for a very suitable class (S1), while the lowest of 5.58 ton/ha was obtained by exchangeable K for class S1. This showed that the combination of PLS-SEM and boundary line analysis was a better approach to developing new land suitability criteria for hybrid maize.

Spatial Modeling of Vegetation Cover for Soil Erosion Control Based on Arc GIS and the RUSLE Models

Deforestation in the Serayu watershed, Central Java province, Indonesia for agriculture and other uses leaves only 0.73% of vegetation. It has triggered a number of problems such as soil loss (erosion), landslides, floods and sedimentation downstream. Environmental damage control needs to be applied through appropriate conservation programs. This study aims to understand the distribution of soil erosion and the effectiveness of soil erosion control by using vegetation cover. Soil erosion modeling and its correlation to vegetation cover was performed by using an Arc GIS based model of the Revised Universal Soil Loss Equation (RUSLE) through five scenarios of vegetation landscape cover such as 10%, 15%, 20%, 25%, and 30% of the total area of the study site. Five parameters namely rain erosivity (R), soil erodibility (K), slope-length (LS) and crop management (C) and conservation practices (P) factor were used to calculate soil erosion. The results indicated 82.25 tons/ha/year soil erosion reduction due to enhancement of vegetation cover from the actual condition 0.73% to the 30% vegetation cover condition. The increase of 5% vegetation landscape cover (forest) detracted the soil erosion rate by 10,20 tons /ha/year. Very high and high soil erosion hazard levels were found in the northern, east, and west watershed areasKeywords: Soil erosion, RUSLE model, GIS, Serayu watershed, Vegetation cover

Driving effects of dynamic geomorphologic environments on gravitational erosion hazards: a case of the Baihetan drainage area of the Jinsha River, China

Driving effects of dynamic geomorphologic environments on gravitational erosion hazards: a case of the Baihetan drainage area of the Jinsha River, China

The integration of RUSLE-SDR lumped model with remote sensing and GIS for soil loss and sediment yield estimation

As a major contributor of land degradation, water borne soil erosion poses a threat to environmental and socioeconomic sustainability worldwide. Recently, various anthropogenic factors have aggravated soil erosion related problems in most of the humid and semi arid parts of the developing countries like India. Therefore, accurate quantification of the spatially distributed soil erosion along with the identification of erosion hot spots is of paramount significance for designing extensive management strategies to combat erosion hazard. The present study aimed to estimate mean annual soil loss in a tropical river basin such as Kumari river basin (KRB, area: 195125 ha) in the Chotanagpur plateau region in India. In addition, the study also quantified mean sediment yield and identified the main sediment sources within the basin. For these purposes, the present study introduced a raster based spatially distributed approach that integrated RUSLE and sediment delivery ratio (SDR) models with remote sensing (RS) and GIS. The results depicted that annual soil loss within the basin varied from 0 to 208.34 t ha – 1 yr – 1 with an average of 1.92 t ha – 1 yr – 1. The computed annual soil loss was about 364.05 × 103 tonnes, of these, 209.46 × 103 (∼58 %) were lost from only 8.93 % of the total basin area at intolerable rate. Similarly, the estimated sediment yield within the basin ranged from 0 to 64.53 t ha – 1 yr – 1 with a mean of 1.15 t ha – 1 yr – 1 and followed a similar distribution pattern of soil erosion. Being characterized by steep topography, the forest patches in the upstream part of the basin showed the most critical erosion risk. The methodology adopted in the current research displayed acceptable correctness and enabled spotting of most vulnerable areas of water erosion and critical sediment sources, initiating a comprehensive anticipating aid for the implementation of proper land management and soil conservation plans. This perspective is surmised to be helpful for extensive study of water erosion in other tropical river basins.

Evaluation of the Success of Forest Land Based on Geographic Information Systems, in Wonosalam District, Jombang Regency

The benefits of forests for life are not only for local communities living around forests, but also for global communities whose lives depend on forests as a resource that is able to provide various functions related to environmental management. The research aims to identify the potential of the Wonosalam forest area planned for UPN Integrated Farming & Forestry Tourism (UIFFT) - KHDTK Wonosalam in support of conservation policies by mapping forest areas based on land suitability characteristics and land availability suitable for KHDTK development. This type of research is survey research. and spatial analysis using Geographic Information Systems. Location in this research was conducted in the Wonosalam Forest Area in Wonosalam District. Wonosalam District is located in Jombang Regency with an area of 121.63 km2. The results of the study can be concluded that 1. the results of the survey of regional characteristics and physical and chemical analysis of the soil for durian, clove and coffee plants have land suitability classes that are actually in accordance with marginal (S3eh) with a limiting factor on erosion hazard while for potential after experiencing improvements that are not overall permanent value obtained is quite appropriate (S2) with various limiting factors but most of the constraints on erosion hazard and land preparation. 2. The direction of forest area development in future research areas based on land suitability is an integrated farming forestry area with a technological approach, and plant suitability so that this area can become a center for research, innovation, education, training, empowerment and community assistance without compromising its function. forests as environmental conservationists in an integrated manner.

Plants Suitability for Landslides Mitigation in the Giritengah Catchment Area, Indonesia

Changes in land use caused by human dependence on land to meet food, clothing, and settlement needs are in line with population growth. This triggers the destruction of watersheds and results in an increased of disasters such as landslides that lead to decrease land productivity and less water throughout the year. This study aims to determine the plant suitability for both annual plant species (forestry plants), and seasonal crops (agricultural crops) in the Giritengah catchment area. In addition, this study also aims to provide the proposed species that are suitable and at the same time allow for land improvement efforts. The results showed that the suitability classes for forestry plant species (teak, sengon, and mahogany) and annual plant species (chili, banana, and cassava) in Giritengah catchment were unsuitable/incompatible (N) with erosion hazard level as the heaviest limiting factor. There are two variable levels of erosion hazard, which are one of the reasons for the unsuitability of these plant species, namely the slope, which tends to be steep and the shallow soil solumn. To overcome this, it is necessary to apply soil and water conservation techniques both technically and vegetative.

Analysis of the Soil Erosion Hazard Level on the East Coast of Minahasa (Case Study of Kombi District)

The development of the Minahasa East Coast area into a tourism area has caused a tendency to change land use. Kombi Subdistrict is one of the areas on the East Coast of Minahasa that has experienced changes in land use with many investors building tourism areas there. The rate of land clearing in the area can accelerate the process of erosion. This research was carried out with the aim of knowing the level of soil erosion hazard on the East Coast of Minahasa, especially in Kombi District, in order to prevent soil damage so that environmental sustainability can be maintained and the development of tourism areas in the area can continue. The method used in this research is the overlay method for making digital maps and calculating erosion using the USLE method. The results of the analysis show that the Minahasa East Coast area, especially in Kombi District, has a light erosion hazard level of 1492.10 Ha, a moderate erosion hazard level of 5036.35 Ha, and a severe erosion hazard level of 6970.94 Ha.
 Keywords: erosion hazard level, soil
 
 Abstrak
 Pengembangan kawasan Pantai Timur Minahasa menjadi kawasan pariwisata, menyebabkan kecenderungan terjadi perubahan pemanfaatan lahan. Kecamatan Kombi adalah salah satu wilayah di Pantai Timur Minahasa yang mengalami perubahan penggunaan lahan dengan banyaknya investor yang membangun kawasan pariwisata di sana. Lajunya pembukaan-pembukaan lahan di daerah tersebut, dapat mempercepat proses terjadinya erosi. Penelitian ini dilaksanakan dengan tujuan mengetahui tingkat bahaya erosi tanah di Pantai Timur Minahasa khususnya di Kecamatan Kombi agar dapat mencegah kerusakan tanah sehingga kelestarian lingkungan dapat terjaga dan pengembangan kawasan pariwisata di daerah tersebut dapat berlanjut. Metode yang digunakan dalam penelitian ini adalah metode overlay untuk pembuatan peta digital dan perhitungan erosi menggunakan metode USLE. Hasil analisis menunjukkan kawasan Pantai Timur Minahasa khususnya di Kecamatan Kombi memiliki tingkat bahaya erosi ringan seluas 1492.10 Ha, tingkat bahaya erosi sedang seluas 5036.35 Ha, dan tingkat bahaya erosi berat seluas 6970.94 Ha.
 Kata Kunci : tingkat bahaya erosi, tanah

Changes in land management practices have reduced wind erosion in the cropping areas of far south-western NSW, Australia

Since the mid-1970s, approximately 250 000 ha of rangelands in semi-arid far south-western NSW, Australia, have been converted to cropping land use, resulting in substantial wind erosion. Wind erosion is of concern because of its adverse impacts on soils, agricultural production, aviation, energy supply, human health and ecosystem function. Over recent decades, multi-faceted extension programs have promoted sustainable land management practices to reduce wind erosion. Repeated biannual paddock surveys were undertaken between 2003 and 2022 to determine (1) the best land management practices (BMPs), that is, those that would reduce erosion while maintaining productivity and profitability, and (2) whether the use of the BMPs changed over time. The BMPs that reduce wind erosion included chemical fallow, standing stubble, and perennial pastures. Between 2003 and 2022, the proportion of sites with BMPs increased from 14% to 75%, and the proportion of sites with wind erosion fell from 23% to 9%. Practices that reduced ground cover and led to frequent erosion have declined, including tilled pasture, tilled stubble and grazed stubble. In drier years, livestock grazing crop stubble exacerbated the erosion hazard. In an attempt to understand where landholders obtain their information for land management practice change, the Western Local Land Services (LLS) conducted a social benchmarking survey in 2020 that indicated that the LLS was the third source of information for practice change after neighbours and other landholders, and stock and station agents. Although the LLS is a source of information, this study could not determine a causal link between LLS programs and practice change. Further research is required to test whether extension programs can reduce the overgrazing of stubble.

A process-geometric visualization of bluff erosion hazards on the Pennsylvania coast of Lake Erie, United States

A process-geometric visualization of bluff erosion hazards on the Pennsylvania coast of Lake Erie, United States

Estimating water erosion in the EL-Mador Valley Basin, South-West Matrouh City, Egypt, using revised universal soil loss equation (RUSLE) model through GIS

Water erosion is among the largest and most crucial problems with soil loss and that is through land degradation in semi-arid regions and the North African areas are especially vulnerable to it. In addition, the EL-Mador Valley Basin is exposed to soil degradation due to climate and topographic properties as well as a human activity. In this scope, the aim of this study is to perform an evaluation of soil degradation hazards in the El-Mador Valley Basin by employing the equation RUSLE and the data of RS within a frame GIS. Furthermore, various raster layers have been designed to RUSLE parameters, such (R), (K), (LS), (C), and (P), and these inputs were merged into a GIS-based framework for measuring the degree of soil degradation. The results demonstrate the ranged values from 0 to > 2500 ton ha–1 year–1, with a geographical average of 54.80 ton ha–1 year–1. In addition, a soil erosion hazard map was created which was divided into five hazard categories: Low (56.56%), Moderate (13.88%), High (8.09%), Severe (8.82%), and Extreme (12.65%). Moreover, these results will be important to create mitigation strategies for regions where the soil loss is high, severe, and extreme, and also to assisting the local administration in setting priorities and basis for decision-makers to create suitable actions to decrease soil erosion hazards.

Risk identification and assessment of irrigated land erosion in Tashkent province, Uzbekistan

Irrigated fields are important assets for agricultural development since they supply vital food and fiber to people all over the world. These areas are, however, also susceptible to erosion, which can result in the deterioration of the soil and a loss in production. It is crucial to identify and evaluate the erosion risk in irrigated areas in order to maintain sustainable agriculture and guarantee the resources' long-term availability. The objective of this study is to create a thorough system for recognizing and evaluating the erosion risk in irrigated areas. The methodology will take into account a number of variables, including climate, topography, soil properties, land management techniques, and other pertinent variables that affect the risk of erosion. To identify and assess the erosion hazard of irrigated lands of the farm named after. S. Rakhimov of the Chinaz district of the Tashkent province, Uzbekistan, we laid 4 key sites, depending on the steepness, length, slope exposure and sown crops, and mapped the soils at a scale of 1:1000. At each site, profiles were laid that sequentially cut all the elements of the slope, from the top to the plume, and all soil varieties found on this slope. In the alignment of the profiles, on all elements of the relief, 25 reference sections were laid, characterizing all soil varieties in this area. To identify the boundaries of the contours of individual soil varieties, a series of hollows and pits were laid. Soil morphology was studied on the reference sections, and soil samples were taken according to genetic horizons for subsequent analysis.

Soil erosion prediction and risk assessment using RUSLE model and GIS techniques in the Nangka watershed

Soil erosion in the Nangka watershed has always been a matter of concern. Over the last decade, soil erosion has led to continuous environmental problems. A thorough examination of the extent of the problem was required to identify an appropriate soil conservation strategy within the watershed. This study was conducted to observe erosion rates and map out the erosion hazard level. Erosion predictions were analysed by using the Revised Universal Soil Loss Equation (RUSLE) model with the help of ArcGIS software. RUSLE was selected because of its quantitative ability to estimate average annual soil erosion and its compatibility with the GIS interface. The potential hazard of soil erosion was classified and ranked into five class categories as set by the national authority. The results reveal that the Nangka watershed is prone to soil erosion with the annual average values ranging from 1.33 Mg·ha –1·y –1 to 2472.29 Mg·ha –1·y –1. High soil erosion rates of 9.8% are in severe (class IV) and very severe (class V) conditions, primarily in the upper course of the watershed. The low annual average of soil erosion (class I and class II), which accounted for 75.95% of the total erosion, mostly took place in the steepness below 35%. The remaining area of 14.25% within the watershed is in moderate condition (class III). It is expected that the results of this study will help the authority in the implementation of soil conservation measures.

Soil Erosion Estimation Using Geospatial Technology: A Study of Jyadul Khola Basin, Gorkha, Nepal

Estimation of soil erosion from drainage basins is essential while assessing the severity and its impact on agriculture, forests, barren land, waterbodies, and built- up areas. Jyadul Khola basin significantly affects the ecological processes that feed into the Budhigandaki River in the south-eastern side of Gorkha District. This paper has attempted to estimate the mean erosion rate based on the erosion severity classes. Remotely sensed Ziyuan-3 satellite image processed in Earth Resources Data Analysis System (ERDAS) Imagine, Geographical Information System (GIS), and Revised Universal Soil Loss Equation (RUSLE) model were used in this study. The land use land cover (LULC) classification results were validated by using confusion matrix by computing overall accuracy and kappa coefficient which is 95% and 0.94 respectively. The basin had been classified into 6 categories based on erosion severity. The results indicated 92.7% of land (0-5 t ha–1 yr–1) is low severe followed by 2.39% (10-20 t ha–1 yr–1) moderate, 2.07% (5-10 t ha–1 yr–1) high, 2.04% (20-40 t ha–1 yr–1) very high, 0.67% (40-80 t ha–1 yr–1) severe and 0.10% of land (>80 t ha–1 yr–1) which is very severe for soil erosion. The total annual mean soil loss was found to be 13526.60 t yr–1 and soil erosion classes ranges from 0 to 305.34 t ha–1 yr–1 for the entire study area. Kuwapani, Lakuri Bhanjyang, Khadkagaun, Garapani and Kaulebhagar area are the most susceptible to soil erosion. It is observed that barren land, steep slopes, and high intensity of rainfall are major factors for soil erosion hazard. This outcome can serve as a foundation for decision-makers to conserve high risk areas and plan effective measure to lessen impending disasters.

Evaluation of the Impact of Land Use Changes on Soil Erosion in the Tropical Maha Oya River Basin, Sri Lanka

Soil degradation is a serious environmental issue in many regions of the world, and Sri Lanka is not an exception. Maha Oya River Basin (MORB) is one of the major river basins in tropical Sri Lanka, which suffers from regular soil erosion and degradation. The current study was designed to estimate the soil erosion associated with land use changes of the MORB. The Revised Universal Soil Loss Equation (RUSLE) was used in calculating the annual soil erosion rates, while the Geographic Information System (GIS) was used in mapping the spatial variations of the soil erosion hazard over a 30-year period. Thereafter, soil erosion hotspots in the MORB were also identified. The results of this study revealed that the mean average soil loss from the MORB has substantially increased from 2.81 t ha−1 yr−1 in 1989 to 3.21 t ha−1 yr−1 in 2021, which is an increment of about 14.23%. An extremely critical soil erosion-prone locations (average annual soil loss > 60 t ha−1 yr−1) map of the MORB was developed for the year 2021. The severity classes revealed that approximately 4.61% and 6.11% of the study area were in high to extremely high erosion hazard classes in 1989 and 2021, respectively. Based on the results, it was found that the extreme soil erosion occurs when forests and vegetation land are converted into agricultural and bare land/farmland. The spatial analysis further reveals that erosion-prone soil types, steep slope areas, and reduced forest/vegetation cover in hilly mountain areas contributed to the high soil erosion risk (16.56 to 91.01 t ha−1 yr−1) of the MORB. These high soil erosional areas should be prioritized according to the severity classes, and appropriate land use/land cover (LU/LC) management and water conservation practices should be implemented as recommended by this study to restore degraded lands.

Integration of RUSLE Model, Remote Sensing and GIS Techniques for Assessing Soil Erosion Hazards in Arid Zones

Soil erosion constitutes one of the main environmental and food security threats, derived from the loss of its productive capacity. With the help of remote sensing (RS), geographic information systems (GIS), and a revised version of the universal soil loss equation (RUSLE), this research has mostly focused on measuring the potential soil erosion hazard and soil water conservation ratio (SWCR) in the El-Minia region of Egypt. Based on the integration of S2A images and the digital elevation model (DEM), geomorphological units of the study area were identified. The RUSLE model includes parameters that allow for mapping soil erosion, such as rain erosivity, soil erodibility, slope length and steepness, soil cover and management, and soil conservation practices. The outcomes revealed that the classes of annual erosion rates of the study area are those of “slight erosion”, “low erosion”, “moderate erosion” and “moderately high erosion”, which represent percentages of 29%, 18%, 33% and 20%, respectively, of the total area. The rate of erosion decreases from east to west. The main erosion factors in the research area are the low vegetation cover and the high slope values. This study highlights the utility of combining the classic RUSLE equation with techniques such as remote sensing (RS) and geographic information systems (GIS) as a basis for assessing current erosion conditions in arid environments and, specifically, for the application of soil management patterns aimed at increasing soil organic matter and any other soil conservation actions. The findings of this study can be used by policymakers to implement soil conservation measures if development projects are to proceed in areas with a high risk of soil erosion. The approach described here is therefore adaptable to similar environments in arid regions.