scholarly journals ALTERNATIVA PARA O CÁLCULO AUTOMÁTICO E ESPACIALIZADO DO FATOR TOPOGRÁFICO DA USLE EM BACIAS HIDROGRÁFICAS

Irriga ◽  
2018 ◽  
Vol 1 (2) ◽  
pp. 6-13
Author(s):  
FRANCISCO EMANOEL FIRMINO GOMES ◽  
George Leite Mamede ◽  
Fernando Bezerra Lopes
Keyword(s):  
Soil Loss ◽  
Shuttle Radar Topography Mission ◽  
Universal Soil Loss Equation ◽  
High Complexity ◽  
Slope Length ◽  
Topographic Factor ◽  
Digital Elevation ◽  
Elevation Model ◽  
E Mail ◽  
Soil Loss Equation

ALTERNATIVA PARA O CÁLCULO AUTOMÁTICO E ESPACIALIZADO DO FATOR TOPOGRÁFICO DA USLE EM BACIAS HIDROGRÁFICAS     FRANCISCO EMANOEL FIRMINO GOMES1; GEORGE LEITE MAMEDE2 E FERNANDO BEZERRA LOPES3   1Departamento de engenharia agrícola/UFC, Doutorando em engenharia agrícola, Fortaleza, CE, Fone:(85)99238-2819, CEP:60440-900, e-mail: [email protected]. 2Instituto de Engenharias e Desenvolvimento Sustentável/ UNILAB, Professor Doutor, Redenção, CE, CEP: 62790-000, e-mail: [email protected] 3Departamento de Engenharia Agrícola, UFC, Professor Doutor, Fortaleza, CE, CEP:60440-900, e-mail: [email protected]     1 RESUMO    Dentre os fatores da Universal Soil Loss Equation (USLE), o fator topográfico é que menos se aproxima da realidade e, em geral, os modelos apresentam elevada complexidade para sua determinação. Neste estudo, portanto objetivou-se calcular o fator topográfico da USLE de maneira simplificada usando técnicas de Sistema de Informações Geográficas (SIG). Para tanto, foi utilizado dados do Modelo Digital de Elevação - MDE obtido a partir do (SRTM -Shuttle Radar Topography Mission), assim foram calculadas as declividades e os comprimentos de rampas usando processamento dos dados matriciais do MDE, para então estimar o fator topográfico. Os valores de fator topográfico variaram de 0,21 a 9,88 com média de 1,97. As técnicas de sistema de informação geográficas mostraram-se eficientes para o cálculo do fator topográfico a partir do MDE.   Palavras-chave: erosão, topografia de encosta, geoprocessamento.     GOMES, F. E. F.; MAMEDE, G. L.; LOPES, F. B. ALTERNATIVE FOR THE AUTOMATIC AND SPACIALIZATION OF USLE TOPOGRAPHIC FACTOR IN WATERSHEDS     2 ABSTRACT   Among the factors of the Universal Soil Loss Equation (USLE), the topographic factor is that it is less close to reality and, usually, the models used for its determination presents high complexity. In this study, therefore, the main objective was to calculate the topographic factor of the USLE in a simplified way using techniques geographic information system (sig). For that, data from the Digital Elevation Model – DEM was used, derived from the SRTM (Shuttle Radar Topography Mission), so slopes and slope length were calculated by processing of the DEM matrix data, so the topographic factor was estimated. The topographic factor values varying from 0.21 to 9.88 with an average of 1.97. The GIS techniques showed efficient for estimating the topographic factor derived from DEM data base.   Keywords: erosion, topography of hillside, geoprocessing.

scholarly journals PENENTUAN TINGKAT BAHAYA EROSI DI WILAYAH DAS BEDADUNG KABUPATEN JEMBER

2020 ◽  
Vol 8 (1) ◽  
pp. 1-11
Author(s):  
Idah Andriyani ◽  
Sri Wahyuningsih ◽  
Rosalina Sekar Arumsari
Keyword(s):  
Digital Elevation Model ◽  
Soil Loss ◽  
Universal Soil Loss Equation ◽  
Data Input ◽  
Aster Gdem ◽  
Digital Elevation ◽  
Elevation Model ◽  
Soil Loss Equation

Kondisi perkembangan Daerah Aliran Sungai (DAS) di wilayah Kabupaten Jember untuk saat ini perlu dievaluasi karena kondisinya sudah rusak mulai dari tahun 1999. Hal ini dapat menimbulkan bencana alam di kawasan DAS seperti tanah longsor, erosi dan banjir yang memakan korban jiwa. Tujuan dari penelitian ini adalah mengetahui besarnya tingkat bahaya erosi yang dipengaruhi oleh beberapa nilai parameter erosi menggunakan metode Revised Universal Soil Loss Equation (RUSLE) di DAS Bedadung. Data input yang digunakan pada penelitian ini yaitu curah hujan tahun 2004 - 2014, peta jenis tanah, peta penggunaan lahan RBI tahun 2014, dan data Digital Elevation Model (DEM) dari ASTER-GDEM. Hasil penelitian menunjukkan bahwa nilai parameter erosivitas hujan (R) DAS Bedadung rata-rata 1708,70 MJ.cm/tahun. Parameter erodibilitas tanah (K) didominasi jenis tanah latosol dengan nilai K sebesar 0,26. Parameter panjang dan kemiringan lereng (LS) didominasi kelas datar yaitu dengan besar kemiringan 0-8%. Parameter vegetasi penutupan lahan dan pengelolaan tanah (CP) didominasi sawah irigasi dengan nilai CP sebesar 0,02. Laju erosi DAS Bedadung sebesar 160,57 ton/ha.tahun, laju erosi ini termasuk pada kondisi sedang. Tingkat bahaya erosi pada DAS Bedadung didominasi pada tingkat sangat rendah yaitu besar erosi berkisar 0-15 (ton/ha.tahun) atau 62,20% dari luas wilayahnya.

scholarly journals Analisis Karakteristik dan Potensi Tingkat Erosi Daerah Aliran Sungai Blorong Kabupaten Kendal Tahun 2013 dan 2018 Menggunakan Sistem Informasi Geografis dan Pendekatan Universal Soil Lost Equation (USLE)

2020 ◽  
Vol 3 (2) ◽  
pp. 63-72
Author(s):  
Achmad Zakky Robbany ◽  
Dhea Sarah Setyorini ◽  
Aldino Maulana Riski ◽  
Santhi Widyastuti
Keyword(s):  
Digital Elevation Model ◽  
Soil Loss ◽  
Universal Soil Loss Equation ◽  
Digital Elevation ◽  
Elevation Model ◽  
Soil Loss Equation

Peningkatan penduduk yang pesat mengakibatkan suatu daerah terus berkembang, salah satunya yaitu berada di Daerah Aliran Sungai (DAS) Blorong. DAS Blorong dengan luas area 208,20 km2 merupakan salah satu sub DAS bagian timur dari DAS Bodri-Kuto yang berada di kabupaten Semarang dan kabupaten Kendal. Penelitian memiliki tujuan untuk mengetahui karakteristik dan tingkat erosi di DAS Blorong. Metode yang digunakan untuk menghitung tingkat erosi di DAS Blorong yaitu menggunakan USLE (Universal Soil Loss Equation). Metode USLE yang dilakukan dengan Sistem Informasi Geografis (SIG) dengan mencari faktor-faktor untuk mendapatkan nilai USLE tersebut,  beserta menganalisa karakteristik DAS dari data digital elevation model (DEM), peta tata guna lahan, peta geologi, dan curah hujan (tahun 2013 dan 2018). Pada DAS Blorong ditentukan karaktersitiknya berdasarkan hulu dan hilir dari DAS tersebut. Tingkat erosi yang terdapat pada DAS Blorong ditinjau dari tata guna lahan di DAS tersebut. Tingkat erosi di DAS Blorong pada tahun 2013 hingga 2018 terjadi peningkatan sebesar 10,78%, dari 852,236,26 ton/Ha/tahun menjadi 944.037,79 ton/Ha/tahun. Berdasarkan identifikasi dan perhitungan, menunjukkan bahwa curah hujan dan perubahan lahan pemukiman, agrikultur, dan ladang merupakan penyumbang terbesar erosi. Rekomendasi yang dapat dilakukan untuk meminimalisir potensi erosi adalah berupa upaya konservasi pada wilayah ini.

scholarly journals Estimation of annual soil erosion dynamics (2005 - 2015) in Pakistan using Revised Universal Soil Loss Equation (RUSLE)

2021 ◽  
Author(s):  
Hammad Gilani ◽  
Adeel Ahmad ◽  
Isma Younes ◽  
Sawaid Abbas
Keyword(s):  
Soil Erosion ◽  
Soil Loss ◽  
Management Practices ◽  
Climatic Factors ◽  
Universal Soil Loss Equation ◽  
Rainfall Erosivity ◽  
Slope Length ◽  
Conservation Practice ◽  
Administrative Units ◽  
Soil Loss Equation

Abrupt changes in climatic factors, exploitation of natural resources, and land degradation contribute to soil erosion. This study provides the first comprehensive analysis of annual soil erosion dynamics in Pakistan for 2005 and 2015 using publically available climatic, topographic, soil type, and land cover geospatial datasets at 1 km spatial resolution. A well-accepted and widely applied Revised Universal Soil Loss Equation (RUSLE) was implemented for the annual soil erosion estimations and mapping by incorporating six factors; rainfall erosivity (R), soil erodibility (K), slope-length (L), slope-steepness (S), cover management (C) and conservation practice (P). We used a cross tabular or change matrix method to assess the annual soil erosion (ton/ha/year) changes (2005-2015) in terms of areas and spatial distriburtions in four soil erosion classes; i.e. Low (<1), Medium (1–5], High (5-20], and Very high (>20). Major findings of this paper indicated that, at the national scale, an estimated annual soil erosion of 1.79 ± 11.52 ton/ha/year (mean ± standard deviation) was observed in 2005, which increased to 2.47 ±18.14 ton/ha/year in 2015. Among seven administrative units of Pakistan, in Azad Jammu & Kashmir, the average soil erosion doubled from 14.44 ± 35.70 ton/ha/year in 2005 to 28.03 ± 68.24 ton/ha/year in 2015. Spatially explicit and temporal annual analysis of soil erosion provided in this study is essential for various purposes, including the soil conservation and management practices, environmental impact assessment studies, among others.

Digital mapping of RUSLE slope length and steepness factor across New South Wales, Australia

Soil Research ◽  
2015 ◽  
Vol 53 (2) ◽  
pp. 216 ◽  
Author(s):  
Xihua Yang
Keyword(s):  
Land Use Planning ◽  
Soil Loss ◽  
Overland Flow ◽  
New South ◽  
New South Wales ◽  
Slope Angle ◽  
Universal Soil Loss Equation ◽  
Slope Length ◽  
South Wales ◽  
Soil Loss Equation

The Universal Soil Loss Equation (USLE) and its main derivate, the Revised Universal Soil Loss Equation (RUSLE), are widely used in estimating hillslope erosion. The effects of topography on hillslope erosion are estimated through the product of slope length (L) and slope steepness (S) subfactors, or LS factor, which often contains the highest detail and plays the most influential role in RUSLE. However, current LS maps in New South Wales (NSW) are either incomplete (e.g. point-based) or too coarse (e.g. 250 m), limiting RUSLE-based applications. The aim of this study was to develop automated procedures in a geographic information system (GIS) to estimate and map the LS factor across NSW. The method was based on RUSLE specifications and it incorporated a variable cutoff slope angle, which improves the detection of the beginning and end of each slope length. An overland-flow length algorithm for L subfactor calculation was applied through iterative slope-length cumulation and maximum downhill slope angle. Automated GIS scripts have been developed for LS factor calculation so that the only required input data are digital elevation models (DEMs). Hydrologically corrected DEMs were used for LS factor calculation on a catchment basis, then merged to form a seamless LS-factor digital map for NSW with a spatial resolution ~30 m (or 1 s). The modelled LS values were compared with the reference LS values, and the coefficient of efficiency reached 0.97. The high-resolution digital LS map produced is now being used along with other RUSLE factors in hillslope erosion modelling and land-use planning at local and regional scales across NSW.

scholarly journals An improved method for calculating slope length (λ) and the LS parameters of the Revised Universal Soil Loss Equation for large watersheds

Geoderma ◽  
2017 ◽  
Vol 308 ◽  
pp. 36-45 ◽  
Author(s):  
Hongming Zhang ◽  
Jicheng Wei ◽  
Qinke Yang ◽  
Jantiene E.M. Baartman ◽  
Lingtong Gai ◽  
...  
Keyword(s):  
Soil Loss ◽  
Universal Soil Loss Equation ◽  
Improved Method ◽  
Slope Length ◽  
Soil Loss Equation

Design and Implementation of Regional LS Factor Computing Tool Based on GIS and Array Operation

2013 ◽  
Vol 394 ◽  
pp. 509-514
Author(s):  
Hong Ming Zhang ◽  
Qin Ke Yang ◽  
Shu Qin Li ◽  
Mei Li Wang ◽  
Ming Ying ◽  
...  
Keyword(s):  
Soil Loss ◽  
Large Scale ◽  
Universal Soil Loss Equation ◽  
Graphic User Interface ◽  
Slope Length ◽  
Long Time ◽  
Area Unit ◽  
User Friendly ◽  
Gis Software ◽  
Soil Loss Equation

For over 40 years, the universal soil loss equation (USLE) and its revised version the revised universal soil loss equation (RUSLE) have been used all over the world for soil mean annual loss per area unit. Because of the watershed erosion models are under developing, many researchers applied the USLE and RUSLE to estimate soil loss in watershed estimations. However, a major limitation is the difficulty in extracting the LS factor. The geographic information system-based (GIS-based) methods which have been developed for estimating the slope length for USLE and RUSLE model also have limitations. A series of ARC/INFO AML program was created that can calculate LS factor for the USLE, however the program need a very long time to run in wide-ranging areas. The flowpath and cumulative cell length-based method (FCL) overcomes this disadvantage but does not consider the following questions: (1) Some original AML program functions are not achieved, so results are different. (2) Using USLE to calculate LS factor that do not adapt to the erosion environment of China. (3) There isnt a friendly graphic user interface. The purpose of this research was to overcome these limitations and extend the FCL method through Integrating CSLE equation. We developed a LS calculation tool (LS-TOOL) in Microsofts .NET environment using C# with a user-friendly interface. Comparing the LS factor calculated with the FCL method and AML method, LS factor values generated by using LS-TOOL method delivers improved results. The LS-TOOL algorithm can automatically calculate slope length, slope steepness, L factor, S factor, and LS factors, providing the results as ASCII files which can be easily used in some GIS software. This study is an important step forward in conducting fast large-scale erosion evaluation.

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