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1

The estimation of water erosion with RUSLE and deposition model : A case study of the Bin El-Ouidane dam catchment area (High Atlas, Morocco)

Nouaim Wafae, Rambourg Dimitri, El Harti Abderrazak, Ettaqy Abderrahim, Merzouki Mohamed, Karaoui Ismail

Journal of Water and Land Development

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2023

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no. 58

136--147

EN

Water erosion is a critical issue for Morocco, especially in its semi-arid regions, where climatic and edaphic conditions only allow erratic soil formation and vegetation growth. Therefore, water erosion endangers human activity both directly (loss of arable land, landslides, mudflows) and indirectly (siltation of dams, river pollution). This study is part of the Kingdom’s effort to assess the risk of water erosion in its territory. It is dedicated to the Bin El-Ouidane dam water catchment, one of the biggest water storage facilities in the country, located in the High Atlas Mountains. The poorly developed soils are very sensitive to erosion in this mountainous area that combines steep slopes and sparse vegetation cover. The calculation of soil losses is carried out with the RUSLE model and corrected by estimating areas of deposition based on the unit stream power theory. This method produces a mean erosion rate of around 6.3 t·ha-1·y-1, or an overall annual loss of 4.1 mln t, consistently with the siltation rate of the dam. Primary risk areas (erosion rates > 40 t·ha-1·y-1) account for 54% of the total losses, while they cover only 7% of the catchment. This distribution of the soil losses also shows that the erosion risk is mainly correlated to slope, directing the means of control toward mechanical interventions.

2

Temporal Analysis of Erosion Risk Classes and Rates in the Wadi Ouergha Watershed, Northern Morocco

Naoui Basma, Tita Asmae, Baghdad Bouamar, Chakiri Said, Sadiki Mohamed, Zerdeb Mohammed Amine, El Omari Mariyam, Lididi Sara

Ecological Engineering & Environmental Technology

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2023

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Vol. 24, iss. 9

150--160

EN

The significance of the issue lies in the pivotal role played by Wadi Ouergha, as a major tributary of Wadi Sebou. This watercourse directly contributes to the El Wahda dam, the largest in the Kingdom of Morocco and the second largest in Africa. With its substantial storage capacity and noteworthy annual sedimentation volume, this dam’s storage capacity is notably impacted. The ongoing decline in the capacity of the El Wahda dam could potentially accelerate due to shifts in surface water mobilization rates and the worsening degradation of marl soils within the catchment, coupled with alterations in vegetation cover. The aim of this study is to examine the changes in the erosion rate within the Wadi Ouergha watershed over a span of 40 years, covering the periods 1980–2000 and 2001–2020. This comparative analysis aims to ascertain whether erosion control measures have effectively reduced the erosion rate in the region over time. To assess soil losses occurring in the Wadi Ouergha watershed, impacting the El Wahda dam, we employed the RUSLE model to determine the rate and vulnerability of the catchment to water erosion. The results indicate that erosion control measures have been effective in combating soil erosion in the potential region with high erosion risk, with a 13.83% reduction in the average erosion rate between the two periods, from 25.3 to 21.8 (tons/hectare/year). This study presents a groundbreaking contribution by unveiling, for the first time, the dynamic evolution of water erosion patterns over time. It offers a comprehensive assessment of the effectiveness of erosion control measures implemented within the most vulnerable zones.

3

Soil Erosion Estimation Using an Empirical Model, Hypsometric Integral and Geo-Information Science – A Case Study

Maliqi Edon, Kumar Nirmal, Latifi Loresa, Singh Sudhir Kumar

Ecological Engineering & Environmental Technology

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2023

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Vol. 24, iss. 4

62--72

EN

An approach that integrates the Revised Universal Soil Loss Equation (RUSLE) model and Geographic Information System (GIS) techniques was used to determine the soil erosion vulnerability of a forested mountainous watershed. The spatial pattern of annual soil loss rate was obtained by integrating geo-environmental variables in a raster data format based geoinformatics methods and tools. Thematic layers including rainfall erosivity (R), soil erodability (K), slope length and steepness (LS), cover management (C), and conservation practice (P) factors were computed to determine their effects on average annual soil loss in the Mitrovica city. The serial thematic map of annual soil erosion shows a maximum soil loss of 112.61 ton·ha-1·y-1 with a close relation to grass land areas, degraded forests and deciduous forests on the steep side-slopes (with high LS). The geographic age of the region shown by the hypsometric analysis was mature to old stage. The serial erosion maps compiled with the RUSLE model and GIS can serve as effective inputs in deriving strategies for land planning and management in terms of environment concerns.

4

Modeling Soil Erosion Using RUSLE and GIS – A Case Study of Korifla Sub-Watershed (Central Morocco)

Eddefli Fatimazahra, Ouakil Abdelhadi, Khaddari Achraf, Tayebi Mohamed

Ecological Engineering & Environmental Technology

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2023

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Vol. 24, iss. 4

128--137

EN

Soil loss is a problem that contributes to land degradation in many countries and Morocco is no exception. Our study focuses on water erosion in Korifla, a sub-basin of the Bouregreg watershed in northern Morocco. The objective is to quantify erosion using the RUSLE method which is based on five factors: Runoff erosivity, soil erodibility, cover factor, topography and conservation practices. These are processed by remote sensing and a geographic information system. The soil loss map shows that on an area of 1838 km2, erosion is estimated to be between 0.00 t/ha/year and 27.61 t/ha/year. The cumulative effect of the factors R, K, LS, C, and P are both the origin of this erosion and its spatial distribution.

5

Assessment of Water Erosion by Integrating RUSLE Model, GIS and Remote Sensing – Case of Tamdrost Watershed (Morocco)

El Assaoui Naïma, Bouiss Charaf Eddine, Sadok Abdelaziz

Ecological Engineering & Environmental Technology

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2023

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Vol. 24, iss. 3

43--53

EN

Water erosion caused by rainfall and runoff, in the Morocco is the main threat of fertile agricultural soil losses causing important silting-up of dams. Most watersheds are characterized by excessive values of Soil Specific Degradation (Average annual soil loss per year and per km2), exceeding in many regions 2000 T/km2 /year. The main objective of this study is to investigate this phenomenon in the Tamdrost watershed located in northwestern Morocco. The methodology is based on integrating water erosion RUSLE model to Geographic Information System and satellite image processing. The aim of the study is to develop digital mapping for the main factors involved in the erosion processes as well as the variation of the average annual quantity of soil losses. The results outcome are: (i) the average value of the specific degradation is about 80 (T/ha/year), reaching a maximum value of 800 T/ha/year and a minimum value of 3 T/ha/year; (ii) The main factors that control water erosion by order of importance are successively: R, LS, K, and C factors. Finally, different maps representing erosion and the main factors involved, are be very helpful for decision makers to better assess this phenomenon and to implement antierosion measures in the threatened areas to support and control the water erosion.

6

Development of a numerical model for sediment yield for the upper Brahmaputra River basin using optimization technique

Sil Briti Sundar, Pathan Shehnaj Ahmed

Acta Geophysica

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2023

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Vol. 71, no. 5

2423--2438

EN

At a watershed scale, soil erosion occurs at a spatially variable rate, posing a significant danger to long-term resource management. The most serious issue has long been regarded as soil erosion. As a result, estimating soil loss and identifying the critical area for implementing optimum management techniques are essential to the programme's success. A numerical model called the sediment-rainfall-watershed area model (SRWA) is built using a spatially distributed RUSLE-based SDR hybridized model to estimate sediment yields in the upper Brahmaputra River watershed. The developed model has been calibrated and validated from 2001 to 2007 and 2008 to 2014, respectively. For the entire period, the statistical performance of the proposed SRWA model and the SDR-RUSLE-based model reveals a correlation coefficient of 0.93 and a Nash–Sutcliffe efficiency coefficient of 0.84. This demonstrates that the SRWA model may assess sediment yield at any upper Brahmaputra basin watershed/sub-watershed outlet.

7

Rola scaleń gruntów w zmniejszaniu zagrożenia erozyjnego

Bożek Piotr, Doroż Arkadiusz, Taszakowski Jarosław

Przegląd Geodezyjny

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2022

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R. 94, nr 11

18--21

PL

Co roku niemal na całym świecie erozja przyczynia się do degradacji gleby, pogorszenia warunków do prowadzenia działalności rolniczej oraz zmiany krajobrazu rolniczego. Straty dla gospodarki światowej wiążą się z kosztami utraconych plonów oraz z kosztami związanymi z rekultywacją zdegradowanych terenów. Proces zapobiegania oraz niwelowania skutków związanych z zagrożeniem erozyjnym jest procesem czasochłonnym, wymagającym dużych nakładów pracy. Redukcja zagrożenia erozyjnego związana jest ze zmianą struktury przestrzennej dla obszarów użytkowanych głównie rolniczo. Scalenie gruntów wpisujące się w kształtowanie obszarów wiejskich jest jednym z najskuteczniejszych narzędzi pozwalającym na zmniejszenie zagrożenia erozyjnego. Do najpopularniejszych narzędzi identyfikujących zagrożenie erozyjne, które może zostać zredukowane w ramach scaleń gruntów zaliczany jest model RUSLE (Revised Universal Soil Loss Equation). Pozwala on na określenie liczby materiału glebowego, który ulega degradacji. Wykorzystuje on dane wysokościowe, dane o użytkowaniu, aby skutecznie wyznaczyć obszary zagrożone.

EN

Every year, almost all over the world, erosion contributes to soil degradation, deterioration of agricultural conditions and changes in the agricultural landscape. The losses to the world economy are related to the costs of lost crops and the costs of rehabilitating degraded land. The process of preventing and reducing the effects of erosion risk is a time-consuming and labor-intensive process. The reduction of the erosion risk is related to the change in the spatial structure of areas used mainly for agriculture. Land consolidation, which is part of the shaping of rural areas, is one of the most effective tools to reduce the risk of erosion. The RUSLE model (Revised Universal Soil Loss Equation) is one of the most popular tools for identifying erosion risk that can be reduced as part of land consolidation. It allows you to determine the number of soil materials that are being degraded. It uses elevation data and usage data to effectively designate risk area.

8

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

Saadi Yusron, Mardiana Sus, Pradjoko Eko

Journal of Water and Land Development

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2022

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no. 55

185--191

EN

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.

9

Assessing the intra-annual variability of agricultural soil losses: a RUSLE application in Nord-Pas-de-Calais, France

Nouaim Wafae, Rambourg Dimitri, Merzouki Mohamed, El Harti Abderrazak, Karaoui Ismail

Journal of Water and Land Development

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2022

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no. 52

210--220

EN

The control of water erosion is an important economic and societal challenge. Reduction of the agronomic potential of the parcels, muddy flows, siltation of dams are harmful consequences that mobilize farmers, water managers, local authorities and scientific researchers. This study focuses on mapping and quantifying seasonal soil losses in the territory of the former Nord-Pas-de-Calais administrative region, using the Revised Universal Soil Loss Equation (RUSLE) which incorporates five factors: rainfall erosivity, soil erodibility, topography, land use and erosion control practices. The seasonal (3-months) time scale is chosen to better account for the parameters governing the soil water erosion, especially rainfall and vegetation cover, that show great asynchronous intra-annual variability. Also, high resolution data concerning agricultural plots allows to evaluate which type of culture are the more subject to soil losses. In Nord-Pas-de-Calais, water erosion occurs almost ubiquitously, but the areas characterized by steep slopes are the most at risk (Artois Hills and Flanders), with loss rates up to 54 t∙ha-1∙y-1. The majority of erosion occurs during fall (46% of the computed annual losses of 1.69∙Mt), on plots left bare after harvest (especially corn and beets crops). The study also demonstrates that extending the intercrop technique over the region, and therefore maintaining a fall and winter cover, could reduce the soil losses by 37%.

10

Using RUSLE and GIS for the soil loss assessment in arid regions: The case of the Ain Sefra catchment in the Ksour Mountains, Algeria

Melalih Ahmed, Mazour Mohamed

Journal of Water and Land Development

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2021

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no. 48

205--214

EN

The loss of soil quality due to erosion is a global problem, particularly affecting natural resources and agricultural production in Algeria. In this study, the Revised Universal Soil Loss Equation (RUSLE) is applied to estimate the risk of water erosion in the Ain Sefra arid watershed (Algeria). The coupling of this equation with Geographic Information Systems (GIS) allows to assess and map the soil loss rates. The land erosion is influenced by many control variables, such as the topographic factor of the terrain and the length of slope (LS factor), rainfall erosivity (R factor), sensitivity of soil to erosion (K factor), presence of vegetation (C factor) and the antierosion cultivation techniques (P factor). To calculate the average annual soil loss, these five factors were considered and multiplied in the RUSLE Equation. The result shows that the average rate of soil loss is estimated at about 5.2 t·ha–1·y–1 over the whole watershed. This study is the first of its kind in the region and aims to assess the soil loss caused by water erosion processes in this arid zone. Consequently, it is essential to take real intervention measures in these upstream areas in order to combat this scourge, based on priorities ensuring the sustainable management of natural resources in the study area.

11

Soil Loss Estimation for Conservation Planning in the Dolago Watershed Central Sulawesi, Indonesia

Naharuddin Naharuddin, Malik Adam, Ahyauddin Ahyauddin

Journal of Ecological Engineering

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2021

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Vol. 22, nr 7

242--251

EN

Soil loss assessment in watersheds is useful in developing plans for the protection and conservation of soil and water in a sustainable manner. This study aimed to determine erosion hazard classification and erosion hazard map using Revised Universal Soil Loss Equation (RUSLE) as the basis of a soil and water conservation planning program. The RUSLE model was used to assess soil loss and guide the soil conservation efforts. Annual rainfall data, digital elevation model (DEM), land use map were used to generate the RUSLE parameters, namely rainfall-runoff erosivity factor (R), soil erodibility factor (K), slope length and steepness factor (LS), cover-management factor (C), and support practices factor (P). Erosion hazard is classified into five classes, namely very low, low, medium, high, and very high. On the basis of the results, at the Dolago watershed, very high erosion hazard was found in dryland of 577.95 t/ha/yr. Meanwhile, very low erosion hazard was found in the rice field of 2.22 t/ha/yr. The results help in planning and implementing soil and water conservation, both vegetatively and mechanically, to minimize the damage to watershed ecosystems. Validation and testing of the RUSLE model should be carried out in future studies because this is a strategic step to develop modeling of sediment yields effectively in an effort to mitigate major land damage in watersheds.

12

Water Erosion Mapping by RUSLE: A Geomatic Approach by GIS and Remote Sensing in the Oued Isser Watershed, Tlemcen, Algeria

Talbi Okacha, Fatmi Belaïd, Benhanifia Khatir, Talbi Djilali

Geomatics and Environmental Engineering

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2021

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Vol. 15, no. 2

89--104

EN

Prolonged water erosion leads to severe soil degradation, with highly visible scars. Consequently, the quantitative and descriptive estimation by mapping of the phenomenon has become the main objective of a great deal of research. It is this perspective that this study takes, based on the Revised Universal Soil Losses Equation (RUSLE) for a relatively accurate estimate, by integrating Arc GIS tools and remote sensing using high spatial resolution (10 m) image from the Sentinel 2A satellite. The model uses data on precipitation, soil, topography and vegetation cover management. The methodological approach taken implements this model in order to optimize its use by the various potential users in their planning and decision making studies. An application was carried out in the Oued Isser watershed (Tlemcen, Algeria). Soil loss maps were produced and the results indicate a high variation in soil losses in the study area and show that the highest values are concentrated on steep slopes, hence the great influence of the topographic parameter relative to other factors in the model.

13

High-resolution soil erodibility K-factor estimation using machine learning generated soil dataset and soil pH levels

Mammadli Nurlan, Gojamanov Magsad

Geodesy and Cartography

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2021

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Vol. 70, no. 1

44--55

EN

Soil Erodibility Factor (K-factor) is a crucial component of a widely used equation for soil erosion assessment known as the USLE (Universal Soil Loss Equation) or its revised version – RUSLE. It reflects the potential of the soil of being detached due to rainfalls or runoffs. So far, an extensive number of researches provide different approaches and techniques in the evaluation of K-factor. This study applies soil erodibility estimation in the soils of the South Caucasian region using soil data prepared by the International Soil Reference and Information Centre (ISRIC) with 250 m resolution, whereas the recent K-factor estimation implemented in the EU scale was with 500 m resolution. Soil erodibility was assessed using an equation involving soil pH levels. The study utilises Trapesoidal equation of soil data processing and preparation, as suggested by ISRIC, for various layers of surface soil data with up to 0-30 cm depth. Both usage of SoilGrids data and its processing as well as estimation of K-factor applying soil pH levels have demonstrated sufficient capacity and accuracy in soil erodibility assessment. The final output result has revealed the K-factor values varying from 0.037 and more than 0.060 t ha h/MJ mm within the study area.

14

Predicting water erosion in arid lands using the GIS-based RUSLE model: A case study of Bedour catchment, central Tunisia

Bedoui Chokri

Journal of Water and Land Development

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2019

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no. 40

59--66

EN

This study was conducted with a view to quantifying soil erosion in arid lands of Tunisia. To do this, we have opted to use the RUSLE model based on geographic information systems. By collecting data on rainfall, soils, vegetation, slopes and conservation practices separately as a layer and determining the pixel values for each of these factors, a quantified assessment of erosion in the basin is obtained. The data superposition and computing, following the model equations and protocol, allowed us to know the spatialized water erosion values at the pixel level. For the whole catchment, the study showed values oscillating between 0 and 163 Mg·ha–1·year–1 with an average annual rate of 3 Mg·ha–1·year–1. With such a low R (rainfall erosivity) factor (between 21.43 and 21.88 MJ·mm·ha–1·h–1·year–1) itself related to low monthly and annual rainfall amounts, the region experiences locally very high annual erosion rates. Soil protection through conservation practices has saved the basin from even higher erosion. While plains cultivated and equipped with contour benches often suffer from low rates of erosion (less than 2 Mg·ha–1·year–1), unused slopes are neglected without protection, resulting in significantly high rates of erosion.

PL

Badania prowadzono, aby ilościowo ocenić erozję gleby na suchych obszarach Tunezji. W tym celu wykorzystano model RUSLE bazujący na systemie informacji geograficznej. Zbiór danych, ich nakładanie i obliczenia prowadzono zgodnie z równaniami i protokołem modelu umożliwiły poznanie erozji w przestrzeni na poziomie pikseli. Badania wykazały, że w całej zlewni nasilenie erozji zmieniało się od 0 do 163 Mg·ha–1·rok–1 ze średnią równą 3 Mg·ha–1·rok–1. Mimo małego współczynnika R (erozyjność opadu), mieszczącego się w granicach 21,43–21,88 MJ·mm·ha–1·h–1·rok–1, który odzwierciedla niewielkie miesięczne i roczne opady, badany region doświadcza lokalnie bardzo wysokiego tempa erozji. Ochrona gleby poprzez odpowiednie działania uratowała zlewnię przed jeszcze większą erozją. Podczas gdy równiny uprawiane z ziemnymi ławami biegnącymi wzdłuż poziomic ulegają mniejszej erozji (mniej niż 2 Mg·ha–1·rok–1), nieuprawiane stoki są pozbawione takiej ochrony, co skutkuje wysokim tempem erozji.

15

Geomodelling of Destruction of Soils of Ukrainian Steppe Due to Water Erosion

Dudiak Nataliia Vasylivna, Pichura Vitalii Ivanovich, Potravka Larisa Aleksandrovna, Stratichuk Natalia Vladimirovna

Journal of Ecological Engineering

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2019

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Vol. 20, nr 8

192--198

EN

Spatial raster distribution models of the values of factors influencing the potential soil erosion hazard were created using GIS technologies. The erosion hazard was estimated using the modified RUSLE (Revised Universal Soil Loss Equation) model. The potential of annual soil loss of arable land was calculated. The spatial gradation of erosion violation of administrative and territorial units in the steppe zone of Ukraine was provided. About 32.7% of arable land that is subject to high erosion hazard was allocated. About 48 administrative and territorial units have a specific area less than 5% of erosion disturbed lands. They are characterized by a resistant type of agrolandscapes regarding the water-erosion processes. Most administrative and territorial units with high erosive-accumulative potential (the percentage of the area is 15% or more) are located in the western and southwestern parts of the steppe zone of Ukraine. The specific area of erosion hazardous lands reaches up to 32% in separate administrative-territorial units. The obtained results allow determining the need for a spatially discrete-distribution implementation of adaptive-landscape anti-erosion design with the elements of soil-protective agriculture.

16

Estimation of annual average soil loss using the Revised Universal Soil Loss Equation (RUSLE) integrated in a Geographical Information System (GIS) of the Esil River basin (ERB), Kazakhstan

Mukanov Yerbolat, Chen Yaning, Baisholanov Saken, Chukwudi Amanambu Amobichukwu, Issanova Gulnura, Abenova Ainura, Fang Gonghuan, Abayev Nurlan

Acta Geophysica

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2019

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Vol. 67, no. 3

921--938

EN

The Revised Universal Soil Loss Equation (RUSLE) has enormous potential for integrating remote sensing and Geographical Information System (GIS) technologies for producing accurate and inexpensive assessments of soil erosion. In this study, the RUSLE method was applied to the Esil (Ishim) River basin (ERB), which is situated in Northern and Central Kazakhstan. The northern part of the ERB extends through the Tyumen and Omsk regions of the Russian Federation to the confluence of the Irtysh River. This article may be of interest to experts and specialists in the field of agriculture, as the findings can assist agricultural producers and government entities in making decisions that prevent soil degradation and promote optimal cropping systems for land and crop cultivation. The objective of this research is to detect, estimate and map areas of land plots most vulnerable to potential soil erosion within the ERB, using the RUSLE model under Arc GIS 10.2. The results reveal that average annual soil loss during the study period ranges from 0 to 32 (t y−1) and that 108,007.5 km2 (48%) of the ERB has no erosion. The remainder of the basin is prone to soil erosion ranging from 1 to 32 t ha−1 y−1, which comprises 117,216.9 km2 (52%), and total soil erosion is 565,368.7 (t y−1). Soil erosion in the ERB is relatively moderate due to low hill steepness and low annual precipitation (198–397 mm). Exceptions occur in plots which feature high slope length steepness, which are scattered throughout the region.

17

Assessing soil loss using GIS based RUSLE methodology. Case of the Bou Namoussa watershed – North-East of Algeria

Bouhadeb C. E., Menani M. R., Bouguerra H., Derdous O.

Journal of Water and Land Development

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2018

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no. 36

27--35

EN

This study aims to estimating annual soil erosion rate and its spatial distribution in the Bou Namoussa watershed located in the North-East of Algeria by applying the revised universal soil loss equation (RUSLE) within a Geographical Information System environment (GIS). The application of the RUSLE model in different natural environments and on every scale takes into account five key factors namely: the rainfall erosivity, the soil erodibility, the steepness and length of slopes, the vegetation cover and the conservation support practices. Each of these factors was generated in GIS as a raster layer, their combination, resulted in the development of a soil loss map indicating an average erosion rate of 7.8 t·ha–1·y–1. The obtained soil loss map was classified into four erosion severity classes; low, moderate, high and very high severity representing respectively 40, 30.48, 22.59 and 6.89% of the total surface. The areas, showing moderate, high and very high erosion rates which represent more than half of the basin area were found generally located in regions having high erodibility soils, steep slopes and low vegetation cover. These areas should be considered as priorities in future erosion control programs in order to decrease the siltation rate in the Cheffia reservoir.

PL

Badania miały na celu oszacowanie rocznego tempa erozji gleb i jego przestrzennego zróżnicowania w zlewni Bou Namoussa w północnowschodniej Algierii z użyciem równania strat glebowych (RUSLE) w ramach systemu GIS. Aplikacja modelu RUSLE w różnych środowiskach naturalnych i w dowolnej skali uwzględnia 5 kluczowych czynników: zdolność erozyjną opadów, podatność gleb na erozję, nachylenie i długość stoków, pokrycie roślinnością i działania ochronne. Każdy z tych czynników został utworzony w GIS w formie warstwy rastrowej. Kombinacja tych warstw umożliwiła opracowanie mapy strat glebowych wskazującej średnie tempo strat równe 7,8 Mg·ha–1·rok–1. Wydzielono 4 klasy natężenia erozji: niskie, umiarkowane, wysokie i bardzo wysokie, reprezentowane odpowiednio na 40, 30,48, 22,59 i 6,89% całkowitej powierzchni. Obszary o umiarkowanym, wysokim i bardzo wysokim tempie erozji gleb pokrywające ponad połowę powierzchni zlewni były zlokalizowane głównie na glebach o wysokiej podatności na erozję, na stromych stokach i na terenach o ubogiej pokrywie roślinnej. Te obszary powinny być traktowane jako priorytetowe w trakcie konstruowania przyszłych programów ochrony przed erozją w celu zmniejszenia tempa zamulania zbiornika Cheffia.

18

Influence of land use changes on spatial erosion pattern, a time series analysis using RUSLE and GIS: the cases of Ambuliyar sub-basin, India

Nasir N., Selvakumar R.

Acta Geophysica

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2018

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Vol. 66, no. 5

1121--1130

EN

Soil erosion and its impact on the land and surface water resources are posing both ecological and socioeconomic threats around the world. In South India, tank systems are quite ancient, supporting rural livelihood including their agricultural needs. But, in recent decades they have lost their significance. The aggravated catchment erosion and resultant siltation have significantly reduced their storage capacity and thereby their functionality. Ambuliyar sub-basin, encompassing 809 irrigation tanks, has once satisfied multifunctional needs of people but now becomes degraded due to siltation. Though desilting of tanks and feeder channels is practiced, the tanks often get silted owing to aggravate soil erosion. Hence, to sustain their life span, it is essential to minimize the erosion in the catchment. Thus, the present study intends to estimate the rate of erosion, analyze their spatial variation through a time series analysis, and ascertain the causative factor. Accordingly, the annual soil loss estimated using Revised Universal Soil Loss Equation method has shown an increase in the rate of erosion from 4084.40 (1996) to 4922.47 t ha−1 y−1 (2016). However, spatially, a non-uniform pattern is inferred, and hence based on the variations, the sub-basin is divided into five zones. In zones I, II, and V, there is an increase in erosion, and in zones III and IV, a decrease is witnessed. Variations studied in conjunction with RUSLE parameters reveal that the improper land use practice has modified the erosion rate and pattern. Further, it is presumed that the silted watercourses might have increased the overland flow, which in turn increased the erosion. Remedial measures such as afforestation, promotion of coconut plantation, and reduction in overland flow by desilting tanks are suggested; thereby, the surface and groundwater resources will be enhanced and in turn the agricultural productivity.

19

Mapping of soil erodibility and assessment of soil losses using the RUSLE model in the Sebaa Chioukh Mountains (northwest of Algeria)

Meghraoui M., Habi M., Morsli B., Regagba M., Seladji A.

Journal of Water and Land Development

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2017

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no. 34

205--213

EN

In Algeria, erosion and solid transport constitute a major constraint to the development of agriculture and to the management of hydrotechnical works (more than 20% are silted). Due to the irregular rains that characterize the Mediterranean semi-arid zones, the topography of the mountainous areas, the fragility of the soils, the absence of vegetation cover and the inappropriate cropping systems, the Sabaa Chioukh Mountains shows a dissected topography, frequent and violent floods. It is therefore absolutely important and crucial to assess, spatially and quantitatively, the effects of soil erosion in order to face the phenomenon and to propose the best strategies for conservation and land management. This study aims to map the soils erodibility, using remote sensing, and Geographic Information Systems (GIS) taking into account the soil types. In order to achieve the objective, we calculated the factors of the RUSLE equation. The results obtained showed that 26,760 ha i.e. 56.58% of our study area are exposed to an annual soil loss of 150 to 200 t∙ha–1. These areas are located in fersiallitic soils and vertisols and especially in non-cultivable areas which have high slope values.

PL

Erozja i transport zawiesiny stanowią w Algierii główne ograniczenie rozwoju rolnictwa i zarządzania infrastrukturą hydrotechniczną (ponad 20% urządzeń jest zamulonych). Z powodu nieregularnych opadów typowych dla półpustynnych obszarów śródziemnomorskich, topografii rejonów górskich, wrażliwości gleb, braku pokrywy roślinnej i niewłaściwych systemów upraw w górach Sebaa Chioukh o zróżnicowanej topografii występują częste i gwałtowne powodzie. Dlatego bezwzględnie konieczne jest dokonanie oceny (w skali przestrzennej i ilościowej) skutków erozji glebowej w celu zmierzenia się z tym zjawiskiem i zaproponowania najlepszej strategii ochrony i gospodarki przestrzennej. Przedstawione badania miały na celu wykonanie map erozyjności gleb z użyciem teledetekcji i systemu GIS z uwzględnieniem typów gleb. Aby to osiągnąć, obliczono współczynniki w równaniu RUSLE. Uzyskane wyniki dowodzą, że 26 760 ha, tzn. 56,58% obszaru badań, doświadcza rocznych strat gleby w ilości od 150 do 200 t∙ha–1. Obszar badań położony jest na glebach krzemionkowo-żelazistych i vertisolach występujących szczególnie na terenach niewykorzystywanych rolniczo o dużym stopniu nachylenia.

20

Mapping erosion prone areas in the Bouhamdane watershed (Algeria) using the Revised Universal Soil Loss Equation through GIS

Bouguerra H., Bouanani A., Khanchoul K., Derdous O., Tachi S. E.

Journal of Water and Land Development

|

2017

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no. 32

13--23

EN

Soil erosion by water is a major problem that the Northern part of Algeria witnesses nowadays; it reduces: the productivity of agricultural areas due to the loss of lands, and leads to the loss of storage capacity in reservoirs, the deterioration of water quality etc. The aim of this study is to evaluate the soil losses due to water erosion, and to identify the sectors which are potentially sensitive to water erosion in the Bouhamdane watershed, that is located in the northeastern part of Algeria. To this end, the Revised Universal Soil Loss Equation (RUSLE) was used. The application of this equation takes into account five parameters, namely the rainfall erosivity, topography, soil erodibility, vegetative cover and erosion control practices. The product of these parameters under GIS using the RUSLE mathematical equation has enabled evaluating an annual average erosion rate for the Bouhamdane watershed of 11.18 t∙ha–1∙y–1. Based on the estimates of soil loss in each grid cell, a soil erosion risk map with five risk classes was elaborated. The spatial distribution of risk classes was 16% very low, 41% low, 28% moderate, 12% high and 3% very high. Most areas showing high and very high erosion risk occurred in the lower Bouhamdane watershed around Hammam Debagh dam. These areas require adequate erosion control practices to be implemented on a priority basis in order to conserve soil resources and reduce siltation in the reservoir.

PL

Erozja wodna gleb jest głównym problemem, którego obecnie doświadcza północna Algieria. Z powodu strat gleby w wyniku erozji zmniejsza się produktywność obszarów rolniczych. Erozja gleb prowadzi również do zmniejszenia pojemności retencyjnej zbiorników wodnych, pogorszenia jakości wody itp. Celem przedstawionych badań była ocena strat gleby spowodowanych erozją i identyfikacja obszarów potencjalnie zagrożonych erozją w zlewni Bouhamdane zlokalizowanej w północno-wschodniej Algierii. W tym celu wykorzystano równanie strat gleby RUSLE. W równaniu wykorzystuje się pięć parametrów: erozję spowodowaną opadami, topografię, erozyjność gleb, pokrywę roślinną i działania zapobiegające erozji. Na podstawie wyników obliczeń za pomocą tego równania i z wykorzystaniem GIS oszacowano średnią roczną wielkość erozji w zlewni Bouhamdane na poziomie 11,18 t∙ha–1∙y–1. W każdej jednostce sieci pomiarowej sporządzono mapę ryzyka erozji, stosując pięć klas ryzyka, 16% ziem mieściło się w klasie bardzo niskiego ryzyka, 41% w klasie niskiego, 28% w klasie umiarkowanego, 12% w klasie wysokiego i 3% w klasie bardzo wysokiego ryzyka. Większość obszaru mieszczącego się w klasach wysokiego i bardzo wysokiego ryzyka to dolne partie zlewni Bouhamdane w okolicach zapory Hammam Debagh. Te obszary wymagają priorytetowego wdrożenia działań zapobiegających erozji w celu zachowania zasobów glebowych i zmniejszenia zamulania zbiornika.