Prediction of soil erosion in pansoon subbasin, malaysia. 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. 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. Downloadable versions of the instructor materials are available from this location on the instructor materials pages. Erodability or erodibility is the inherent yielding or nonresistance of soils and rocks to erosion. How to calculate rainfall erosivity factor using qgis. Mar 06, 2019 this article is a simplified guide on how to calculate rainfall erosivity factor using qgis. The results show moderate range of soil erodibility, the figure show that the soil erodibility ranges from 0. Rusle k values california state water resources control board. 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.
Table 2 soil erodibility k factor stewart et al 1975 soil. Pdf isolating erosivity and erodibility components in erosion by. K soil erodibility factor provided gis map of k factor for the state or. Due to monsoon influence, the annual precipitation has a proportion of 61. Spatial and temporal variation of wind erosion climatic. Rusle2 is a powerful tool for conservation planning, inventorying erosion rates over large areas, and estimating sediment production that might become sediment yield in watersheds. It is dependent on the physical characteristics of rainfall, which include raindrop size, drop size distribution, kinetic energy, terminal velocity etc. Select county from the quick navigation menu au, select navigate by, state and county and click view. Generally, the quantity of erosion yield is dependent upon the ability of rain to detach the soil particles i. Assessing changes in wind erosion climatic erosivity in chinas dryland region during 19612012 1265 has an annual mean temperature of 3. Erodibility and infiltration characteristics of five major. Wind erosion climatic erosivity is a measure of the climatic tendency to produce con ditions conducive to wind erosion.
Rusle k values california state water resources control. Estimation of rainfall erosivity using 5 to 60minute fixedinterval rainfall data from china s. R values vary a lot depending on regional weather patterns and local geography. See the bulletin section for additional information, including an erosivity map for the eastern us. Erosivity r factor values for locations where a particular user will apply rusle are in a database file in the rusle computer program. Soil erodibility and processes of water erosion on hillslope rorke b. An overview of methodologies and applications shuiqing yin, mark a. The procedure to obtain soil erodibility for a particular area is as follows. The rusle uses the simple equation a r x k x ls x c x p. However, no absolute numerical values can be determined for them because rainfall erosion results. The erodibility of soil particles was determined using the comparison of gsd between sediment and original soil. Erosion sensitive lands are those less resistant to.
Soil erosion assessment using gis and revised universal soil. Relationship between soil erodibility, rainfall erosivity. Soil erodibility and processes of water erosion on hillslope. 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 result shows that 66% 7433 ha of the pansoon subbasin is classified. When rainfall erosivity exceeds the soil erodibility, soil erosion occurs. Assessment of soil particle erodibility and sediment. Finetextured soils that are high in clay have low k values about 0. Rainfall erosivity is an index that describes the power of rainfall to cause soil erosion. Assessment of soil particle erodibility and sediment trapping. The ls topography, c soil cover and management and p support practices are nondimensional and have a value of 1 as the soil erodibility. Thus, erosion is a function of the erosivity of the rain and the erodibility of the soil. R factors are estimates of annual erosivity values for sites throughout the country. The map of rainfall erosivity in europe gives a spatial overview of the erosive energy of rain.
Here we quantify variations in rock erodibility within channel cross sections using laboratory abrasion mill experiments on bedrock surfaces extracted from streams. Strong winds erode, and dryness increases the susceptibility of the. Effect of land use types and slope on soil erodibility. Rainfall erosivity and erodibility of inceptisols in the southwest. Scientists are certain that changes in climate and land use will affect the erodibility of soils and regoliths and also the erosivity of rainstorms nearing et al. The following soil properties were used to determine the appropriate soil erosion category for nearly all soil types in iowa.
Land use map was used to produce coverage and management practice factor. Rainfall erosivity is a term that is used to describe. 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. Highly erodible geologic materials are readily displaced and transported by water. Rainfall erosivity and erodibility of inceptisols in the southwest colombian andes volume 32 issue 1 m. The rainfall erosivity factor was defined as a powerlaw function with the 2yr, 30min rainfall as the base number and 1. Highly erodible land definitions nrcs caribbean area. Values used by rusle2 for average monthly temperatures and precipitation are available in. Conceptually, rainfall erosivity is the capacity of rain to produce erosion where as soil erodibility is the susceptibility of the soil to be eroded. Assessing changes in wind erosion climatic erosivity in. Rusle2 also uses values for the bimonthly distribution of the erosivity. The soil erosion hazard map was created by using all the five rusle layers, rainfallrunoff erosivity factor, soil erodibility factor, slope length and steepness factor, cover and management factor, and support and conservation practices factor.
It is defined as the potential ability of rain to cause the erosion. National pollutant discharge elimination system npdes please update your url link to the rainfall erosivity factor calculator for small construction sites to. The processing of ombrographic data from 29 meteorological stations of the czech hydrometeorological institute chmi, according to the terms of the universal soil loss equation for calculating long term loss of soil through water erosion, erosion hazard rains and their occurrence have been selected, with their relative amount and erosiveness rfactors determined for each month and. The erodibility of soil particles were strongly affected by the rainfall erosivity ei 30. Gis on cameron highlands, malaysia for hydropower development soo huey teh a 30 ects credit units master. One key parameter for modelling soil erosion is the soil erodibility, expressed as the kfactor in the widely used soil erosion. This article is a simplified guide on how to calculate rainfall erosivity factor using qgis. Rainfall erosivity is the capability of rainfall to cause soil loss from hillslopes by water. Rusle revised universal soil loss equation more accurately represents longterm averages.
So we will explain what rainfall erosivity factor is, why and when you need to calculate rainfall erosivity factor. One of the important variables used in the design of grassed waterways is the soil erodibility category. Both rusle models indicated problematic areas along the ramla valley system, namely, in nuffara hill and the upper part of the nadur slope. Average annual erosivity values range from 781 x 102 fttonsacre in the wet zone to 154 x 102 fttonsacre in the dry zone.
As a result, erosion is directly proportional to these two factors, and erodibility is the amount of soil loss divided by rainfall erosivity index. Erosivity and erodibility 981 erosion by water erosion. Characterization of erodibility using soil strength and. Draft users reference guide revised universal soil loss equation version 2 rusle2 prepared for usdaagricultural research service washington, d. R rainfall erosivity factor, expressed by an average erosion index. The slope lengthgradient, rainfallrunoff erosivity, crop and vegetation cover and the support practice of each field were very important factors when considering soil erosion. Results also show that the study area has high rainfall erosivity hence making it very susceptible to erosion. They are used as surrogate measures of the impact that rainfall has on erosion from a particular site.
Thus, the soil erosion is the function of both erosivity and erodibility. Investigation and computation of the soil erodibility factor. A term connected to erosivity is erodibility as both are functions of erosion. R is an indication of the two most important characteristics of storm erosivity. Erosivity and erodibility in encyclopedia of environmental management.
The resulting value is called the rainfallrunoff erosivity factor, abbreviated with the letter r. Rainfall and runoff erosivity r factor student materials. Where a is the average annual soil loss in tonsacreyear, r is the rainfallrunoff erosivity factor, k is the soil erodibility. While rusle has been used before in europe, rusle2015 improves the quality of estimation.
The problem is the high uncertainty of the main parameters of global change, leading to uncertainty in the response of soils and regoliths to these changes. Estimation of rainfall erosivity using 5 to 60minute. Erosivity can be defined as the potential ability of the rain to cause erosion. Usle developpy,ed by scientists at ars, scs, purdue univ. 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. 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 surface that eroded. Rainfall erosivity factor calculator for small construction. Erodibility definition and meaning collins english. This page provides basic information about soil erodibility. Erodibility klc erosivity is a measure of the forces actually applied to the soil by the erosive agents of raindrop impact, waterdrops falling from plant canopy, and surface runoff. A preliminary investigation of the erodibility of the. A high erodability implies that the same amount of work exerted by the erosion processes leads to a larger removal of material. Mar 01, 2012 the national runoff and soil loss data rainfall erosivity factor soil erodibility factor topgraphy factor cover factor erosion control practices factor predicted soil loss tonsacrecenter was established at purdue university in 1954 to locate, assemble, and consolidate data from soil erosion studies throughout the unitedstates.
Stormwater technical guidance soil erodibility 4 map c and soils explorer d. The greatest obstacle to soil erosion modelling at larger spatial scales is the lack of data on soil characteristics. The amount of erosion will, therefore, depend upon the combination of the power of the rain to cause erosion and the ability of the soil to withstand erosion. Clay was the most erodible soil particle which showed 2. Assessing changes in wind erosion climatic erosivity in china. The soil erodibility factor, k for the area is greater than 0. In this article we will discuss about erosivity and soil erodibility.
Conceptually, rainfall erosivity is the capacity of rain to produce erosion, whereas soil erodibility is the susceptibility of the soil to be eroded. Application of revised universal soil loss equation rusle. This form provides notice to epa that you, the project operator identified in section i of this form, are certifying that construction activity at the project site identified in section ii, will take place during a period when the rainfall erosivity factor is less than five 40 cfr 122. Before we proceed, its important for us to mention a few points about rainfall erosivity factor. Learn more about using the different versions of integrate materials download a pdf of all web pages for the student materials. Soil erodibility factor k the soil erodibility factor k relate to the average longterm soil and soil profile response to the erosive power associated with rainfall and runoff. Erosivity is a measure of the potential ability of soil, regolith, or other weathered material to be eroded by rain, wind.
Highly erodible soil map units a soil map unit with an erodibility of 8 or greater is highly erodible land hel. The student materials are available for offline viewing below. Erosivity definition and meaning collins english dictionary. Erodibility indices two indices for erodibility are given, the emerson test which measures soil aggregate stability and the k erodibility factor used in the universal soil loss equation usle. Among these factors, soil erodibility factor k is one of the key factors that required for soil erosion determination and or prediction across the world 10 and was. Soil erosive power of rainfall in the different climatic. The musgrave equation was the first to include a rainfall erosivity factor in the process of soil erosion estimation musgrave, 1947. This means that the impact of soil, topography, and management on runoff and the resulting impact of runoff on sheet and rill erosion are subsumed in the other rusle factors k, soil erodibility. Epa has established the r factor of less than 5 as the criteria for determining waiver eligibilty. Values of rainfall erosivity factor for the czech republic in. Calculating erodibility index the erodibility index ei for a soil map unit is determined by dividing the potential erodibility for the soil map unit by the loss tolerance t.
Pdf the rainfall erosivity r and soil erodibility k factors of the universal soil loss equation usle were determined on two sites in the. Although the rainfall intensity and the erosivity of the simulated rainstorm between 900z. Erodibility and infiltration characteristics of five major soils of southwest spain s. Determining and mapping soil erodibility factor case study. Erodibility describes or is a measure of the inherent resistance of geologic materials soils and rocks to erosion. Soil loss erosion rate is com puted by substituting values for each rusle factor to represent conditions at a specific site. 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. This factor also correlated with the siltfine sand soil population. Download a zip file that includes all the web pages and downloadable files from the student materials. Rainfall erosivity and erodibility of inceptisols in the. Modern definitions of rainfall erosivity began with the development of the universal soil loss equation usle, where rainfall characteristics were statistically related to soil loss from thousands of plotyears of natural rainfall and runoff data. Currently, there are various models to quantify wind erosivity, among which the wind erosion equation weq and the revised wind erosion equation rweq are wellknown and widely used 7,8.
Bryan soil erosion laboratory, faculty of forestry, uni. A direct link to the materials for this video can be. Evaluation of usle and rusle estimated soil on rangeland. Variability of rock erodibility in bedrockfloored stream. K soil erodibility factor for specific soil horizon. Download a pdf of all web pages for the student materials. The rainfall erosivity r and soil erodibility k factors of the universal soil loss equation. Rusle2 uses six factors for climatic erosivity, soil erodibility, slope length, slope steepness, covermanagement, and support practices to compute soil loss. Determining and mapping soil erodibility factor case. Pdf rainfall erosivity and erodibility of inceptisols in the.
Rainfall erosivity was calculated using data from rainfall gauging stations installed in the study area and the recommended method from rusle renard et al. Erosivity is used around the world for assessing and predicting rates of soil erosion on agricultural lands. Given a constant discharge, the product of erodibility and erosivity varies with. The samples of soil scope of the study the study focused on the characterization of erodibility using soil strength and stressstrain indices for soils in anambra state in southeastern nigeria and was limited to three sites in the state namely awka, agulu nanka and nnewi. Difference between erosivity and erodibility soil erosion. Relationship between soil erodibility, rainfall erosivity and. Erosivity for a single storm is the product of the storms energy e and its maximum 30 minute intensity i30 for qualifying storms.
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