Erodibility Factor Research Articles

Long-Term Effects in Structures: Background and Recent Developments

This article addresses the often overlooked but critical long-term factors of creep, shrinkage, ageing and corrosion in civil engineering structures. The paper emphasizes their substantial impact on structural mechanical resistance and safety, drawing attention to key examples like the Civic Tower in Pavia, the Koror-Babeldaob Bridge and dams in the USA. By exploring the challenges faced in modern engineering, the article sheds light on the need to consider these effects. Various models for predicting creep and shrinkage in concrete structures are introduced as potential solutions. In conclusion, the paper highlights the necessity for engineers to navigate the intricacies of material behaviour for successful construction amidst evolving challenges.

Enhanced CMAS and hot corrosion degradation of YSZ thermal barrier coating with nano powders

Thermal barrier coatings are used to protect hot section parts of gas turbine engines. These coatings are subject to corrosion due to impurity elements in the fuel and dust absorbed from the atmosphere into the engine. The rough and porous surface nature of plasma-sprayed coatings facilitates the penetration of these factors into the coating. Coatings are damaged prematurely as a result of corrosion. In this study, nano-structure YSZ, YSZ + Al2O3, YSZ + TiO2, and YSZ + Al2O3 + TiO2 coatings were deposited on plasma sprayed YSZ coating by electrophoretic deposition method. Hot corrosion and CMAS resistance were investigated. The coatings were characterized by SEM, XRD, AFM, and microhardness before corrosion tests. The changes in the coatings after corrosion tests were characterized by SEM and XRD. The penetration behavior of corrosive factors was examined by elemental mapping with EDS. Nanostructure coatings deposited on APS YSZ made the surfaces of as-sprayed coatings more stable. The ability of these nanolayers to prevent pure penetration into coatings during hot corrosion and CMAS is limited. However, the Al2O3 + TiO2-doped nanostructure YSZ reduced the bond-layer oxidation. In addition, the addition of Al2O3 + TiO2 to the EPD deposited layer also reduced the tetragonal-monoclinic phase transformation that occurred in YSZ as a result of corrosion. Al2O3 and TiO2 additives alone are not effective in improving the corrosion behavior of coatings. Nanostructured coatings deposited with the EPD technique can help protect plasma-sprayed thermal barrier coatings against corrosion.

Applicability Comparison of GIS-Based RUSLE and SEMMA for Risk Assessment of Soil Erosion in Wildfire Watersheds

The second-largest wildfire in the history of South Korea occurred in 2022 due to strong winds and dry climates. Quantitative evaluation of soil erosion is necessary to prevent subsequent sediment disasters in the wildfire areas. The erosion rates in two watersheds affected by the wildfires were assessed using the revised universal soil loss equation (RUSLE), a globally popular model, and the soil erosion model for mountain areas (SEMMA) developed in South Korea. The GIS-based models required the integration of maps of the erosivity factor, erodibility factor, length and slope factors, and cover and practice factors. The rainfall erosivity factor considering the 50-year and 80-year probability of rainfall increased from coastal to mountainous areas. For the LS factors, the traditional version (TV) was initially used, and the flow accumulation version (FAV) was additionally considered. The cover factor of the RUSLE and the vegetation index of the SEMMA were calculated using the normalized difference vegetation index (NDVI) extracted from Sentinel-2 images acquired before and after the wildfire. After one year following the wildfire, the NDVI increased compared to during the year of the wildfire. Although the RUSLE considered a low value of the P factor (0.28) for post-fire watersheds, it overestimated the erosion rate by from 3 to 15 times compared to the SEMMA. The erosion risk with the SEMMA simulation decreased with the elapsed time via the vegetation recovery and stabilization of topsoil. While the FAV of RUSLE oversimulated by 1.65~2.31 times compared to the TV, the FAV of SEMMA only increased by 1.03~1.19 times compared to the TV. The heavy rainfall of the 50-year probability due to Typhoon Khanun in 2023 generated rill and gully erosions, landslides, and sediment damage in the post-fire watershed on forest roads for transmission tower construction or logging. Both the RUSLE and SEMMA for the TV and FAV predicted high erosion risks for disturbed hillslopes; however, their accuracy varied in terms of the intensity and extent. According to a comparative analysis of the simulation results of the two models and the actual erosion situations caused by heavy rain, the FAV of SEMMA was found to simulate spatial heterogeneity and a reasonable erosion rate.

Erodibility Indices and Soil Loss from Different Land uses in Owukpa and Okaba Bioregion of Lower Coal Measures Geological Sediments of the Anambra Basin, Nigeria

The study on erodibility indices and soil loss from different land uses in Owukpa and Okaba bioregion of lower coal measures geological sediments of the Anambra Basin, Nigeria was conducted forested, cultivated and residential lands. Thirty-nine (39) representative soil samples were collected at a depth of 0 – 20 cm using auger, labeled and preserved to the laboratory for standard laboratory procedures. The percentage of different grain sizes Moisture content, organic carbon, organic matter content, soil pH, bulk density, particle density, porosity, soil structural index, specific gravity, particle size and permeability were verified. The three land uses were predominantly sandy soil and classified as sandy loam, moderate Permeability, low moisture and clay contents. Dispersion, Erosion, Clay and Modified Clay ratios where high, while Water Stable Aggregates was low. Cultivated land use has the highest value of erodibility factor K (0.12) and predicted soil loss was 18.22 tons/ha/yr. Residential land use value of erodibility factor K was 0.10 and the predicted soil loss of 14.80 Tons/ha /yr while forested land use K was lowest (0.08) with predicted soil loss of 11.84 tons/ha/yr. Using one way ANOVA at p ? 0.05 the different land use patterns did not significantly influence erodibility factor and soil loss in the study area.

Assessment of soil erosion in the Irga watershed on the eastern edge of the Chota Nagpur Plateau, India

Human activities to improve the quality of life have accelerated the natural rate of soil erosion. In turn, these natural disasters have taken a great impact on humans. Human activities, particularly the conversion of vegetated land into agricultural land and built-up area, stand out as primary contributors to soil erosion. The present study investigated the risk of soil erosion in the Irga watershed located on the eastern fringe of the Chota Nagpur Plateau in Jharkhand, India, which is dominated by sandy loam and sandy clay loam soil with low soil organic carbon (SOC) content. The study used the Revised Universal Soil Loss Equation (RUSLE) and Geographical Information System (GIS) technique to determine the rate of soil erosion. The five parameters (rainfall-runoff erosivity (R) factor, soil erodibility (K) factor, slope length and steepness (LS) factor, cover-management (C) factor, and support practice (P) factor) of the RUSLE were applied to present a more accurate distribution characteristic of soil erosion in the Irga watershed. The result shows that the R factor is positively correlated with rainfall and follows the same distribution pattern as the rainfall. The K factor values in the northern part of the study area are relatively low, while they are relatively high in the southern part. The mean value of the LS factor is 2.74, which is low due to the flat terrain of the Irga watershed. There is a negative linear correlation between Normalized Difference Vegetation Index (NDVI) and the C factor, and the high values of the C factor are observed in places with low NDVI. The mean value of the P factor is 0.210, with a range from 0.000 to 1.000. After calculating all parameters, we obtained the average soil erosion rate of 1.43 t/(hm2•a), with the highest rate reaching as high as 32.71 t/(hm2•a). Therefore, the study area faces a low risk of soil erosion. However, preventative measures are essential to avoid future damage to productive and constructive activities caused by soil erosion. This study also identifies the spatial distribution of soil erosion rate, which will help policy-makers to implement targeted soil erosion control measures.

Influence of long-term operation on the properties of main gas pipeline steels. A review

Underground pipelines during operation are affected by mechanical and corrosive factors. The susceptibility of cathodically protected pipe to hydrogen degradation increases, which contributes to stress-corrosion cracking. It is believed that the main factor in pipeline steels degradation is deformation aging, which increases strength and reduces plasticity. Volume microdamages also develop in long-time exploited steels. But in many cases, the base metal and welded joints of long-term operated pipelines retain satisfactory performance. Due to the high value of viscosity and plasticity of the metal in an as-received state, the metal state of long-term operated gas pipelines can be considered satisfactory.

Analysis of soil erosion changes and influencing factors based on the CSLE model and GeoDector in Dongjiang River Basin of China

AbstractSoil and water conservation and protection are of great importance to China, as the source of the Pearl and Xiang Rivers, and the main rare earth mining area, the ecology of Dongjiang River Basin, is very fragile. In this paper, the Chinese soil loss equation and the Geodetector method are used to analyze the spatial and temporal patterns and the impact factors of soil erosion in this area from 2016 to 2020. The results show that (1) Soil erosion intensity in the Dongjiang River Basin from 2016 to 2020 is mainly mild, with the soil erosion intensity in the Dongjiang River Basin in 2016 being the largest in five years. (2) The erosion modulus shows an increasing trend with the increase of slope. In terms of vegetation, when the vegetation cover is <30%, the soil erosion modulus is the largest, which is easy to induce soil erosion. When the vegetation cover is >60%, the soil erosion modulus is the smallest, which effectively slows down the occurrence of soil erosion. Rainfall is proportional to the soil erosion modulus and soil erosion. (3) The results of Geodetector indicate that the single factor sizes are land use > vegetation > slope > precipitation, and interaction factors all show a nonlinear enhancement. (4) The proper allocation of land use types, the prohibition of steep slopes for cultivation, and the restoration of forestry can effectively prevent and control soil erosion in the area.

Analysis of Diseases and Conservation of Modern Residential Buildings in Macao: A Case Study of the Lou Family's Big House

The Lo Family Building is a typical representative of modern residential architecture in Macao, which has its own characteristics in terms of architectural history, culture, spatial layout and fittings. In recent years, many scholars have been carrying out research on the Lu Family's Great House. At present, there is insufficient research and protection on the disease analysis and architectural protection related issues of the restored Lu Family's Great House. This paper through the literature research, field research methods on the Lu family house specific investigation and research, analysis of existing disease phenomena, concluded that the Zheng family house is currently the main external finishes discolouration, cracking, weathering, plant erosion and human factors and other types of disease, and its characteristics and causes of a brief collation of the analysis; and finally, based on the above materials, put forward the subsequent protection measures. To a certain extent, it provides some new thoughts for the conservation of modern residential buildings in Macao.

Modelling Soil Erosion Using RUSLE and GIS for Kadalundi River Basin in Kerala, India

The main objective of the study was to estimate the potential average annual soil loss from Kadalundi river basin using RUSLE model and to prepare the spatial distribution map of soil erosion hazard using GIS to suggest suitable soil conservation and management measures for the basin. The individual factor maps for each factor in the RUSLE equation were prepared and multiplied in raster calculator to obtain the spatial distribution map of soil erosion with the help of ArcGIS. The daily rainfall data, basic soil data, Digital Elevation Model (DEM) and satellite imageries were used as the input data for the calculation of rainfall erosivity factor, soil erodibility factor, topographic factor, cover management factor and conservation practice factor. The results indicated an average annual erosion of 5.48 t·ha-1·yr-1 in the basin during the period of 2001 to 2021. The total quantity of soil washed away from the basin was 694836.60 t·yr-1. The estimated values of R-factor ranged from 938.97 MJ·mm·ha-1·h-1·yr-1 to 1102.65 MJ·mm·ha-1·h-1·yr-1, and the computed erodibility factor values varied between 0.0075 to 0.025 t·h·MJ⁻1·mm⁻1. The topographic factor value of the basin was found between 0 to 9.07. The basin had C-factor values of 0.08 to 1.10 and the P-factor values varied from 0.1 to 1. The spatial distribution map of erosion suggest that major part of the basin is under slight erosion class and only a minor part is under very severe erosion class. Areas in the very severe erosion class is characterised by moderate to steep slopes, or in other words areas with less slope is having slight erosion. As most of the area of the basin is having slight erosion, simple agronomical measures can be adopted for the mitigation purposes.

An Integrated Risk Assessment Methodology of In-Service Hydrogen Storage Tanks Based on Connection Coefficient Algorithms and Quintuple Subtraction Set Pair Potential

At present, there have been a number of hydrogen storage tank explosions in hydrogen filling stations, causing casualties and property losses, and having a bad social impact. This has made people realize that the risk assessment and preventive maintenance of hydrogen storage tanks are crucial. Therefore, this paper innovatively proposes a comprehensive risk assessment model based on connection coefficient algorithms and quintuple subtractive set pair potential. First of all, the constructed index system contains five aspects of corrosion factors, material factors, environmental factors, institutional factors and human factors. Secondly, a combined weighting analysis method based on FAHP and CRITIC is proposed to determine the weight of each indicator. The basic indicators influencing hydrogen storage tanks are analyzed via the quintuple subtraction set pair potential and full partial connection coefficient. Finally, the risk level and development trend of hydrogen storage tanks in hydrogen filling stations are determined by a combination of the three-category connection coefficient algorithms and the risk level eigenvalue method. The results of our case analysis show that the proposed risk assessment model can identify the main weak indicators affecting the safety of hydrogen storage tanks, including installation quality, misoperation and material quality. At the same time, it is found that the risk of high-pressure hydrogen storage tanks is at the basic safety level, and the development trend of safety conditions holds a critical value. The evaluation results can help establish targeted countermeasures for the prevention and maintenance of hydrogen storage tanks.

Characteristics and dynamic mechanism of rill erosion driven by extreme rainfall on karst plateau slopes, SW China

Driven by climate change and increased human activities, the frequency and intensity of extreme rainfall events are increasing, leading to increased risk of water erosion on slopes in karst rocky desertification (KRD) areas. However, the driving factors (rainfall intensity, slope gradient, and the degree of underground fissure pore), characteristics, and dynamic mechanisms of rill erosion on KRD slopes under extreme rainfall have received limited attention. A rainfall simulation experiment was performed to investigate the driving factors of rill erosion on KRD slopes under extreme rainfall events. The experiments were conducted using an erosion flume (4 m long, 1.5 m wide and 0.35 m deep) with five rainfall intensities (50, 105, 115, 125 and 145 mm·h−1), three-level slope gradients (5°, 15° and 25°), and three typical degrees of underground pore fissure (1 %, 3 % and 5 %). The results showed that extreme rainfall significantly stimulated the formation and development of rill erosion on KRD slopes. In particular, rainfall intensity and slope gradient significantly affected rill erosion (p < 0.05), whereas the degree of underground pore fissure did not have any distinct effect. Increasing rainfall intensity intensified rill erosion by significantly (p < 0.05) promoting the rill density, total rill surface area, and longest of rill length. With increasing slope gradient, the rill density, rill distribution density, and average rill depth significantly increased (p < 0.05). Moreover, extreme rainfall events exacerbated surface soil erosion by enhancing the hydrodynamic characteristics of slope runoff. Rill erosion was most sensitive to the shear stress of runoff, and rill density was found to be the most suitable rill index for describing surface soil erosion on the slope under extreme rainfall. The findings provide valuable insights into the characteristics and mechanisms of soil erosion in karst regions under future climate warming.

Identification of corrosion factors in blast furnace gas pipe network with corrosion big data online monitoring technology

To mitigate the accelerated corrosion of blast furnace gas pipelines induced by severe environmental conditions, this study has established an extensive high-throughput sensor system in the field. It leverages corrosion big data technology to investigate the corrosion factors affecting industrial gas pipelines and to precisely analyze the influence of related variables. The results indicated that temperature reduction is the driving factor that causes increased pipeline corrosion. On one hand, temperature fluctuations impact the evaporation and condensation of moisture in the tube. On the other hand, temperature fluctuations, in conjunction with corrosive gases, exhibit significant coupling effects, resulting in more severe corrosion. In addition, critical points for relative humidity and temperature are evident. When humidity exceeds 50%, corrosion in the pipe begins to increase, reaching its peak at 70%. The increase in temperature has a slowing effect on pipeline corrosion, reaching a peak value at 40°C. The response of corrosion rate to the concentration of corrosive gases follows a linear pattern. Based on these observations, we propose an effective corrosion control scheme.

Soil Loss Estimation by Water Erosion in Agricultural Areas Introducing Artificial Intelligence Geospatial Layers into the RUSLE Model

The existing digital soil maps are mainly characterized by coarse spatial resolution and are not up to date; thus, they are unable to support the physical process-based models for improved predictions. The overarching objective of this work is oriented toward a data-driven approach and datacube-based tools (Soil Data Cube), leveraging Sentinel-2 imagery data, open access databases, ground truth soil data and Artificial Intelligence (AI) architectures to provide enhanced geospatial layers into the Revised Universal Soil Loss Equation (RUSLE) model, improving both the reliability and the spatial resolution of the final map. The proposed methodology was implemented in the agricultural area of the Imathia Regional Unit (northern Greece), which consists of both mountainous areas and lowlands. Enhanced soil maps of Soil Organic Carbon (SOC) and soil texture were generated at 10 m resolution through a time-series analysis of satellite data and an XGBoost (eXtrene Gradinent Boosting) model. The model was trained by 84 ground truth soil samples (collected from agricultural fields) taking into account also additional environmental covariates (including the digital elevation model and climatic data) and following a Digital Soil Mapping (DSM) approach. The enhanced layers were introduced into the RUSLE’s soil erodibility factor (K-factor), producing a soil erosion layer with high spatial resolution. Notable prediction accuracy was achieved by the AI model with R2 0.61 for SOC and 0.73, 0.67 and 0.63 for clay, sand, and silt, respectively. The average annual soil loss of the unit was found to be 1.76 ton/ha/yr with 6% of the total agricultural area suffering from severe erosion (&gt;11 ton/ha/yr), which was mainly found in the mountainous border regions, showing the strong influence of the mountains in the agricultural fields. The overall methodology could strongly support regional decision making and planning and environmental policies such as the European Common Agricultural Policy (CAP) and the Sustainable Development Goals (SDGs).

An application of gabions for design of coastal protection structures in lakes

With large areas of water reservoirs and lakes, the wave runoff distance is also large, resulting in the high waves in the wind blow direction. These waves intensively disrupt the coast of the lake or water reservoir. Another intense factor of coastal erosion is ice. A lot of engineering measures for the coastal protection of reservoirs and especially for lakes are used: reinforced concrete slabs, blocks, jibs, cellular systems (geosynthetics), etc. An eroded coastline, reshaped by installing a coastal protection structure using gabion construction, is analysed in this research. Gabions are designed to protect banks and slopes from fast water flow (water speed over 5 m·s–1) and ice impacts. They are designed according to geotechnical principles, assessing stability according to the limit design situations specified in Eurocode 7 (EN 1997-1). The aim of this work is to illustrate the features of wave and ice loads and geotechnical design situations evaluated in the design of a coastal protection structure made of gabions.

Construction and Optimization of Corrosion Map in a Broad Region of Acidic Soil via Machine Learning

Machine learning has been widely applied to exploring the key affecting factors for metal corrosion in some local regions. However, there is a lack of systemic research and a practicable prediction model for metal corrosion in a broad region. In this paper, the corrosion map of Q235 steel in a broad region of acidic soils of Hunan province of Central China was constructed and optimized via field experiment and machine learning. Both the experimental and optimized corrosion maps confirmed that the corrosion rate of the steel decreased from the western to the eastern part of the province. The concentrations of pH, F−, Cl−, NO3−, HCO3−, K+, and Mg2+ were the key affecting factors in the broad region of acidic soils of the province. Among them, the contribution rate of the HCO3− concentration was higher than that of other factors. The optimization model based on the ordinary least squares could be used for the optimization of the corrosion map of steels in a broad region of acidic soils. The optimized corrosion map was a good alternative to the estimation methods for the corrosion rate of steel in soil.

Rare-earth elements improving the corrosion resistance of YSZ/CMAS heterojunction with stacking faults: First-principles calculation

Stacking faults cannot be fully eliminated from yttrium partially stabilized zirconia (YSZ) ceramic coatings. However, their influence on the corrosion resistance of YSZ ceramics has remained unclear up till now. In this study, the impact of stacking faults on the corrosion resistance of YSZ with or without Nd dopant in CaO, MgO, Al2O3 and SiO2 (CMAS) melts was characterized via first-principles calculations. As expected, the stacking faults decrease the corrosion resistance of YSZ, especially at the saddle point along the slip way within the YSZ(111)V surface. Moreover, the Nd dopant can increase the corrosion resistance of YSZ due to its enhanced structural stability and enlarged wetting angle. Thoroughly analyzing the growth of stacking faults, it is found that the most pronounced effect of Nd dopant on the corrosion resistance of YSZ occurs only at the initial and final stages, whereas being less noticed at the saddle point of the slip way of faults. In addition, compared to the earlier studies, it is established that the largest penetration depth within the ceramic is achieved by Si ions, which broadens the knowledge about the main corrosion factors, as well as reveals the weakest O-Ca bond and the largest diffusion constants of Ca and Mg ions. Thus, the findings of this work open up new prospects for understanding the corrosion mechanism of YSZ TBCs in CMAS melt.

Modeling Sediment Production In Urban Environments: Case Of Russian Cities

The aim of this study is to provide a tool to assess sediment production in an urban area. The urban environment is affected by a variety of anthropogenic and natural factors that, in particular, lead to the sediment production. The storage of sediments in the urban landscape negatively affects the quality of the urban environment. The model was developed on the basis of landscape studies conducted in residential areas of six Russian cities. The model takes into account (1) the influence of precipitation, spring snowmelt, and vehicles, (2) the influence of erosion factors for two seasons: warm (t&gt;5°C) and cold (t&lt;5°C), and (3) the presence of disturbed surfaces. The application of the developed model to Ekaterinburg city conditions returned sediment production equal to 1.2 kg/m2/y. A comparison of seasonal values shows that sediment production in cold season is 2.5 times higher than in the warm season. In the absence of the disturbed surfaces, sediment production decreases to 0.44 kg/m2/y. Modeling showed a correlation between sediment production in Russian cities and duration of the cold season. The efficiency of various urban area maintenance practices and cleaning measures were evaluated in terms of sediment production and storage. The developed model presented in this paper is based on research in Russian cities, but can be applied to assess the formation of sediment and measures to reduce the value of its accumulation in the urban environment in different regions of the world.

A contrastive characterization of pure Mg and AZ91D alloy based on the testing of mechanical, corrosion, wear, and erosion properties

Abstract Magnesium alloy of grade AZ91D is utilized for a variety of applications in aircraft design and frames, as well as vehicle engine radiators, bumpers, and suspension components to reduce the weight of automobiles. This research compared the mechanical, corrosion, wear, and erosion resistance of pure Mg to that of AZ91 alloy. The corrosion media was NaCl, NaOH, and MgSO4, and the weight loss method was utilised to evaluate corrosion. The pin-on-disc configuration was utilized to assess the dry sliding wear mechanism of the Pure Mg and AZ91D alloy. Pure monolithic Mg and AZ91D magnesium alloy have a low resistance to wear as a result of an increase in contact temperature brought about by a shift of operational conditions. Erosive wear is caused when solid particles in a liquid or air jet strike a surface. Significantly influencing the erosive wear are particle velocity, impact angle, and erodent particle size. In this work, the erosive wear of AZ91D was studied using an Air jet erosion tester. SiO2 was used as the eroding material, and the flow rate of the eroding material and air was 5 gm min−1. The erosive factor experiments are designed using Taguchi orthogonal array (L16). The erosive factor response is erosion rate and primarily regulated by three factors as angle (30°, 45°, 60°, and 90°), time (5 and 10 min) and, contact pressure (1 and 2 bar). The results of the experiments showed that the rate of wear increased with increasing pressure, and that the angle of impact of the jet at 60° caused the most wear of any of the tested angles. Analysis of variance (ANOVA) shows that time is the most important factor in determining erosive rate for AZ91D. SEM is used to investigate the structure and morphology of worn-out materials, and its findings are then confirmed.

A contribution to preservation of salt-laden construction materials: An effective, eco-friendly and inexpensive system of renovation plasters

Prolongation of construction service-life is a crucial way of reducing maintenance costs and carbon footprint related to civil engineering industry. Salinity and dampness are recognized as the main factors affecting porous materials stability. Hence, it is essential to provide effective and easily accessible measures against them. The main goal of the presented manuscript is to satisfy this need by proposing a complex system of renovation plasters, which combines cost effectiveness with high quality. Five renders’ compositions, i.e., one base and four top plasters are designed and extensively studied. Apart from tests required by Association of Science and Technology of Building Maintenance and Monuments Preservation (ger. Wissenschaftlich-Technische Arbeitsgemeinschaft für Bauwerkserhaltung und Denkmalpflege, WTA), the experimental analysis also includes testing of resistance to corrosion factors, such as UV-aging, or cyclic frost action among others. The presented results confirm that the designed materials meet WTA requirements, but also maintain their properties for a long period of time. Since the proposed plasters consist solely of widely available and cheap components, the final price of a ready-to-use render is reduced by 90 % comparing to commercial mortars available in the market. Additionally, the life cycle analysis (LCA) proves that the proposed materials are eco-friendly solutions in comparison to conventional plasters.

Analysis of erosion hazard level and land rehabilitation pattern with the RUSLE method based on GIS at Wai Tala Watershed in West Seram Regency Maluku Province

This study used the Revised Universal Soil Loss Equation (RUSLE) and Geographical Information System (GIS) to estimate the annual rate of soil loss, map erosion factors, and recommend a suitable pattern of land rehabilitation in Wai Tala watershed, Regency of Western Seram. The research material used in this study were rainfall data for 38 years, Digital Elevation Model Nasional (DEMNAS) Image Map, Rupa Bumi Indonesia (RBI), geology, soil, land use, and watershed boundaries of Maluku Province. Field research was conducted on 187 land units, and each land unit contained RUSLE erosion factors: topography, soil type, and land use. The spatial distribution of erosion factors was processed using the Arc.GIS10.8, and the soil erosion rates were estimated using the RUSLE method, then corrected using the land degradation model developed in small islands in Maluku. The results showed that the level of erosion hazard in the Wai Tala watershed was none to slight (mean = 3.54 t/ha/yr), moderate erosion (21.52 t/ha/yr), high erosion (110.01 t/ha/yr), and very high erosion (252.84 t/ha/yr). The recommended land rehabilitation patterns that can reduce annual soil loss lower than the tolerable limit are maintaining the none to slight erosion areas with the present land uses in particular primary and secondary forests, and with reforestation or agroforestry patterns combined with low to high-density garden plants or with low to high densities cover crop at the moderate to very high erosion areas.