This article is a simplified guide on how to calculate rainfall erosivity factor using qgis. An official website of the united states government. Erodibility of agricultural soils, with examples in lake and mendocino counties anthony toby ogeen, uc cooperative extension assistant soil resource specialist, department of land, air, and water resources, uc davis. It should be possible in future to predict areas with high erosion risks based on these concepts. A direct link to the materials for this video can be. In this study, we proposed a composite erodibility index dust occurrence ratio, dor and examined its interannual variation at a typical steppe site abagaqi in xilingol grassland, china, during spring of 1974. Assessing changes in wind erosion climatic erosivity in. A r k ls c p where a estimated average soil loss in tons per acre per year r rainfallrunoff erosivity factor k soil erodibility factor l slope length factor s slope steepness factor c. Sustainability free fulltext evaluation of climatic. A number of other equations have been developed for soils.
Wind erosion climatic erosivity is a measure of the climatic tendency to produce con ditions conducive to wind erosion. Wind erosion occurs when the shear stress exerted on the surface by the wind exceeds the ability of the surface materials to resist detach ment and transport. Wanga a school of geography, beijing normal university, key laboratory of environmental change and natural disaster, ministry of education, beijing, china b usdaars, southwest watershed research center, united states. Soil erodibility food and agriculture organization. Soil erosion assessment using gis and revised universal. Estimation of rainfall erosivity using 5 to 60minute.
Because the mechanics behind erosion depend upon the competence and coherence of the material, erodability is treated in different ways depending on the type of. This model is based on the combination of the five factors erosivity, erodibility, topography, vegetation cover and support practices that directly influence this phenomenon. The soil erodibility factor k is a measure of erodibility for a standard condition. Soil where x 1 is % silt multiplied by 100 % clay, x 2 is % or ganic matter, x 3 is the soil structure code used in the u. The gaussian process regression gpr model used to interpolate the rfactor point values to a map showed a good performance for both the crossvalidation dataset r 2 0. Erodibility is defined as the vulnerability or susceptibility of the soil to erosion. Before we proceed, its important for us to mention a few points about rainfall erosivity factor. The study of erosion by soil scientists has been focused largely on estimating soil erodibility and rainfall erosivity. Conceptually, rainfall erosivity is the capacity of rain to produce erosion, whereas soil erodibility is the susceptibility of the soil to be eroded. Erodibility describes or is a measure of the inherent resistance of geologic materials soils and rocks to erosion. Assessing changes in wind erosion climatic erosivity in chinas dryland region during 19612012 1265 has an annual mean temperature of 3.
Highly erodible geologic materials are readily displaced and transported by water. Erodibility and infiltration characteristics of five major. The effect of erodibility on dust occurrence remains poorly understood. R is an indication of the two most important characteristics of storm erosivity. A term connected to erosivity is erodibility as both are functions of erosion. Soil erosive power of rainfall in the different climatic.
Rusle k values california state water resources control. Determining and mapping soil erodibility factor case. Each parameter will be described in more detail in this report. Ei 30 is the most commonly used rainfall erosivity index, where e is the total kinetic energy per unit area during a precipitation event mj. Rfactor as used in the usle and the revised usle rusle relates to the mean annual sum of ei 30 values. A high erodability implies that the same amount of work exerted by the erosion processes leads to a larger removal of material. The soil erodibility factor kfactor is a quantitative description of the inherent erodibility of a particular soil. Erosivity definition and meaning collins english dictionary. Developing a nomograph for estimating erodibility factor. Relationship between soil erodibility, rainfall erosivity. Given a constant discharge, the product of erodibility and erosivity varies with. An overview of methodologies and applications shuiqing yin, mark a.
Among these factors, soil erodibility factor k is one of the key factors that required for soil erosion determination andor prediction across the world 10 and was. The relationship between soil erodibility, which is hard to measure, and modeled infiltration rate were rarely researched. Conceptually, rainfall erosivity is the capacity of rain to produce erosion where as soil erodibility is the susceptibility of the soil to be eroded. The rainfall erosivity factor calculator can be used to help determine if your small construction site qualifies for stormwater discharge waivers. The rainfall erosivity r and soil erodibility k factors of the universal soil loss equation. When rainfall erosivity exceeds the soil erodibility, soil erosion occurs. Erosivity definition of erosivity by the free dictionary. Bonifacio1 1disafa, university of torino, largo braccini 2, 10095 grugliasco, to, italy 2natrisk, research centre on natural risks in mountain and hilly environments, university of torino, largo braccini 2, 10095 grugliasco, to. Erodability or erodibility is the inherent yielding or nonresistance of soils and rocks to erosion. The emerson tests were carried out by a laboratory staff and indicate the degree of moisture and work required to induce dispersion of the sample. Soil aggregation, erodibility and erosion rates in mountain soils nwalps, italy s. Strong winds erode, and dryness increases the susceptibility of the. Soil aggregation, erodibility and erosion rates in.
It is a function of the physical characteristics of the rainfall. Rainfall erosivity and erodibility of inceptisols in the southwest. R rainfall erosivity factor, expressed by an average erosion index. Highly erodible land definitions nrcs caribbean area.
Soil erodibility and processes of water erosion on hillslope rorke b. This page provides basic information about soil erodibility. Erosivity for a single storm is the product of the storms energy e and its maximum 30 minute intensity i30 for qualifying storms. The greatest obstacle to soil erosion modelling at larger spatial scales is the lack of data on soil characteristics.
Rainfall erosivity and erodibility of inceptisols in the. Erodibility definition of erodibility by the free dictionary. For a particular soil, the soil erodibility factor is the rate of. Erodibility definition and meaning collins english.
The ls topography, c soil cover and management and p support practices are nondimensional and have a value of 1 as the soil erodibility. Nearing, pasquale borrelli, and xiaochan xue the rainfall erosivity factor r factor is one of six erosion factors in the universal soil loss equation usle, which together reflect the combined effects that. A unit plot is defined as a ploughedcontinuous fallow land having a uniform 9% slope steepness and 22. Rainfall erosivity and erodibility of inceptisols in the southwest colombian andes volume 32 issue 1 m. K soil erodibility factor for specific soil horizon. Erodibility of agricultural soils, with examples in lake. Pdf the rainfall erosivity r and soil erodibility k factors of the universal soil loss equation usle were determined on two sites in the. The map of rainfall erosivity in europe gives a spatial overview of the erosive energy of rain.
R is the rainfallrunoff erosivity factor, k is the soil erodibility factor, ls is the slope length and degree, c is the landcover management factor, and p is the conservation practice factor2. How to calculate rainfall erosivity factor using qgis. Rainfall erosivity is a term that is used to describe. While erodibility is an intrinsic material property resulting from characteristics, such as grain size and degree of cementation, erosivity depends upon hydraulic factors including discharge and channel curvature. However, the term is often used more loosely dusan, 1982. Bryan soil erosion laboratory, faculty of forestry, uni. Pdf rainfall erosivity and erodibility of inceptisols in the.
Soil erodibility and processes of water erosion on hillslope. Soil erodibility factor k soils vary in their susceptibility to erosion. Soil erodibility is usually regarded as the susceptibility of a soil to erode. Historically, the term erosivity was first associated with an rfactor rainfallrunoff erosivity factor in the universal soil loss equation usle. Here, the soil erodibility factors k and k e in the usle, k i and k 1 in the wepp were calculated and the infiltration rates were modeled based on the designed laboratory simulation experiments and proposed infiltration model, in order to build their relationship. The soil erodibility factor k represents both susceptibility of soil to erosion and the amount and rate of runoff, as measured under the standard unit plot condition. Estimation of rainfall erosivity using 5 to 60minute fixedinterval rainfall data from china s. Comparison of soil erodibility factors in usle, rusle2. One key parameter for modelling soil erosion is the soil erodibility, expressed as the kfactor in the widely used soil erosion. Pdf isolating erosivity and erodibility components in erosion by.
For the usle, the concept of soil erodibility was introduced as the k factor, which is defined as the average rate of soil loss per unit of rainfall erosivity index from a unit plot zhang et al. Historically, the terms erosivity and erodibility were originally associated with the r and k factors in the universal soil loss equation usle, a r k l s c p 1. Due to monsoon influence, the annual precipitation has a proportion of 61. The k factor is defined as the average annual rate of soil loss per unit erosivity index measured on a continuously cleantilled fallow plot with a gradient of 9% and a slope length of 22. Rainfall erosivity was calculated using data from rainfall gauging stations installed in the study area and the recommended method from rusle renard et al.
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