Automatic Determination Of The Topographic Factor Required In The Universal Soil Loss Equation

Author(s):  
D. Benmouffok ◽  
D.n.h. Horler
2004 ◽  
Vol 8 (1) ◽  
pp. 103-107 ◽  
Author(s):  
N. Diodato

Abstract. The computation of the erosion index (EI), which is basic to the determination of the rainfall-runoff erosivity factor R of the Revised Universal Soil Loss Equation (RUSLE), is tedious and time-consuming and requires a continuous record of rainfall intensity. In this study, a power equation(r2 = 0.867) involving annual erosion index (EI30-annual) in the Mediterranean part of Italy is obtained. Data from 12 raingauge stations are used to derive and then test a regional relationship for estimating the erosion index from only three rainfall parameters. Erosivity rainfall data derived from 5 additional stations are used for validation and critical examination. The empirical procedures give results which compare satisfactorily with relationships calibrated elsewhere. Keywords: erosion index, rainfall, erosivity, Revised Universal Soil Loss Equation


Irriga ◽  
2018 ◽  
Vol 1 (2) ◽  
pp. 6-13
Author(s):  
FRANCISCO EMANOEL FIRMINO GOMES ◽  
George Leite Mamede ◽  
Fernando Bezerra Lopes

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.


2019 ◽  
Vol 7 (2) ◽  
pp. 100-111
Author(s):  
Miskar Maini ◽  
Junita Eka Susanti

Standar permintaan engineering pesawat agar desain bangunan infrastruktur di area Air Strip Runway 2600 yang ada dapat mempunyai fungsi lain. Sedangkan kondisi lain sangat menentukan keselamatan karena lahan di sekitar Air Strip Runway 2600 Bandara Depati Amir (PGK) jika tidak ditutupi vegetasi seperti rumput, kondisi lain lahan yang belum ditutupi vegetasi di sekitar Air Strip Runway 2600 berpotensi akan mengalami erosi lahan, kemudian hasil erosi lahan ini akan terbawa oleh aliran air sehingga akan masuk ke saluran drainase yang akan menyebabkan sedimentasi pada saluran drainase tersebut, akhirnya akan berkurang efektifitas kinerja saluran drainase tersebut. Metode yang digunakan untuk memprediksi laju rata-rata erosi di area Air Strip Runway 2600 dengan memperhitungkan faktor erosivitas hujan, erodibilitas tanah, kemiringan lereng atau panjang lereng, pengelolaan tanaman dan konservasi tanah, yang masing masing tata guna lahan tersebut mengacu pada Masterplan Ultimate Bandara Depati Amir (PGK). Perhitungan dilakukan menggunakan persamaan USLE (Universal Soil Loss Equation) yang dikembangkan oleh Wischmeier dan Smith (1965, 1978), kemudian Sediment Delivery Ratio (SDR) dan Sediment Yield.Hasil penelitian ini, prediksi laju erosi permukaan pada area Air Strip Runway 2600 Bandara Depati Amir (PGK) tahun pertama yang mencapai 5,60 mm/tahun atau 100,76 Ton/Ha/tahun, laju erosi tahun kedua mencapai 3,38 mm/tahun atau 60,84 Ton/Ha/tahun dapat diklasifikasikan ke dalam kelas bahaya erosi sedang (kelas III) dan nilai SDR adalah sebesar 56,3%, nilai sediment yield (SR) pada tahun pertama sebesar 5.887,59 Ton/Tahun, pada tahun kedua ketika rumput pada area Air Strip telah tumbuh dengan sempurna terjadi penurunan hasil sediment yield yaitu nilai SR sebesar 3.554,85 Ton/Tahun.


2005 ◽  
Vol 214 (1-3) ◽  
pp. 118-123 ◽  
Author(s):  
Süleyman Özhan ◽  
A. Nihat Balcı ◽  
Necdet Özyuvaci ◽  
Ahmet Hızal ◽  
Ferhat Gökbulak ◽  
...  

2019 ◽  
Vol 12 (3) ◽  
pp. 859
Author(s):  
Joaquim Pedro de Santana Xavier ◽  
Alexandre Hugo Cezar Barros ◽  
Daniel Chaves Webber ◽  
Luciano José de Oliveira Accioly ◽  
Flávio Adriano Marques ◽  
...  

Dentre os diversos métodos indiretos para estimar as perdas de solo por erosão, a Equação Universal de Perdas de Solo (EUPS) é a mais utilizada devido a sua robustez e por ser constituída de uma simples estrutura fatorial, que integra fatores naturais e antrópicos atuantes na perda de solos. A erosão é um dos fenômenos mais danosos ao solo e às atividades humanas e por isso seu estudo é importante. Para o cálculo das perdas de solo por meio da EUPS, a avaliação da erosividade das chuvas (fator R) é essencial, pois estima o fenômeno produzido pelas chuvas. O objetivo deste trabalho foi avaliar três metodologias disponíveis de obtenção da erosividade das chuvas para a região do semiárido pernambucano, avaliando sua influência nos resultados da EUPS. Os três modelos selecionados para estimar o Fator R foram desenvolvidos por Wischmeier e Smith (mais conhecido e utilizado), por Silva que estimou valores para diversas regiões do País e por Cantalice e outros que trabalharam especificamente para cada região climática do estado de Pernambuco. Os resultados indicam que as metodologias de Wischmeier e Smith e Silva obtiveram resultados de erosividade da chuva semelhantes, tendo Silva alcançado valores maiores. Cantalice e outros obtiveram os resultados mais baixos. Os resultados da EUPS indicam que, quantitativamente, os diferentes fatores R geram grande diferença nas perdas de solo, porém, qualitativamente chegam a resultados semelhantes na classificação de áreas de maior erosão, de acordo com a FAO. Logo, as três metodologias são viáveis na identificação de áreas prioritárias para a mitigação da erosão.   A B S T R A C TAmong several indirect methods to estimate soil erosion loss, the Universal Soil Loss Equation (EUPS) is the most used due to its robustness and because it is constituted of a simple factorial structure that integrates natural and anthropic factors which act in the loss of soils. Erosion is one of the most damaging phenomena to the soil and the human activities, evidencing the importance of studying it. The evaluation of rainfall erosivity (R factor) is essential for the calculation of soil loss through the EUPS, since it is possible to estimate how significant rainfall is to the occurrence of this phenomenon. The objective of this work was to evaluate three methodologies to obtain the rainfall erosivity available for the semi - arid region of Pernambuco, evaluating its influence on the results of the EUPS. The three models used to estimate the R-factor were developed by Wischmeier and Smith, the best known and used model, Silva who estimated values for several regions of the country and Cantalice and others who worked specifically for each climatic region of the state of Pernambuco. As a result, very similar results of rainfall erosivity were obtained between Wischmeier and Smith´s and Silva´s methodology, with Silva reaching higher values of energy amplitude, while Cantalice and others obtained the lowest results. The results of EUPS indicate that, quantitatively, the different R factors generate a large difference in soil loss, but qualitatively they reach similar results in the classification of areas where erosion are greater, according to the FAO. Therefore, the three methodologies are feasible in the identification of priority areas for erosion mitigation.Keywords: soil, rainfall erosivity, USLE, GIS


Author(s):  
Hammad Gilani ◽  
Adeel Ahmad ◽  
Isma Younes ◽  
Sawaid Abbas

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.


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