These student materials complement the a growing concern instructor materials. Research article spatiotemporal changes of rainfall. Rainfall erosivity estimation based on rainfall data collected over a. The results show that, for 49 of the 55 stations, a strong positive correlation r 2 0. A number of other event erosivity indices have been proposed. Data have been collected from 1541 precipitation stations in all european union eu member states and switzerland, with temporal resolutions of 5 to 60 min. A separate rainfall erosivity waiver must be provided for each construction site qualifying for the waiver. Pdf rainfall erosivity index is an important index to evaluate the soil loss due to rainfall. The purpose of this study is to assess rainfall erosivity in europe in the form of the rusle rfactor, based on the best available datasets. 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. The rainfall erosivity index for a rain fall event energyintensity values ei30 is calculated from the total kinetic energy. This method is based on the concept, that the erosion takes place only at threshold.
Rainfall erosivity factor calculator water data and. Visit rainfall erosivity factor calculator for more information, please see the construction rainfall erosivity waiver fact sheet pdf 12 pp, 2. The new general construction permit 20090009 includes the option allowing small construction site 1 and rainfall erosivity value rvalue for their sites given location and time frame compute to less than or equal to 5. This example is for region 7 colorado river basin region. Determination of rainfall erosivity index american journal of. If your small construction project is located in an area where epa is the permitting authority and your r factor is less than five, you qualify for a low erosivity waiver lew from. The resulting value is called the rainfallrunoff erosivity factor, abbreviated with the letter r. Spatiotemporal average rainfall erosivity factor map has been generated for india. Rainfall erosivity impacts all stages of hillslope erosion processes and is an important factor the r factor in the revised universal soil loss equation. Assessing rainfall erosivity indices through synthetic. You may need a pdf reader to view some of the files on this page. The rainfall erosivity index r, determined for imo state was based on data made available from one station. Rainfall erosivity event daily rainfall erosivity monthly rainfall erosivity annual rainfall erosivity rainfall data rainfall data rainfall data applicability of regression models rmse, mape, and bias spatial distribution comparison of regression models kriging assessment of three regression equations rj p j 12. The results were not satisfactory because of the different behavior of each index.
Pdf a scenario of rainfall erosivity index research. Epa rainfall erosivity factor calculator website open. Estimation of rainfall erosivity using 5 to 60minute. Universal index for calculating rainfall erosivity. Determination of rainfall erosivity index r for imo. 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 cause soil loss by rill and interrill erosion on hillslopes by precipitation. Evaluation of annual rainfall erosivity index based on. The rainfall erosivity is related to the kinetic energy of rainfall. Rainfall erosivity index is an important index to evaluate the soil loss due to rainfall. Assessing rainfall erosivity indices through synthetic precipitation series and artificial neural networks roberto a. Table 1 is based on 120 rainfall distribution zones for the continental u. It is well known that soil losses are frequently due to a few intense rainfall events 1, 3. Erosivity and erodibility in encyclopedia of environmental management. The most common rainfall erosivity index is the r factor of usle.
Assessing rainfall erosivity indices through synthetic precipitation series and artificial neural networks. Rainfall erosivity wavier home page california state. If your small construction project is located in an area where epa is the permitting authority and your r factor is less than five, you qualify for a. At global scale, this is the first time ever that an erosivity database of such dimension is compiled. Mannkendall, pearsons correlation and sens slope tests were used to establish the trend in time series rainfall data and their correlation.
The rainfall erosivity index for a rainfall event, ei 30, is calculated from the total kinetic energy and maximum 30 min intensity of individual events. This study has a variety of applications in erosion prediction. Moreover, the study presents the regions and seasons under threat of rainfall erosivity. The rainfall erosivity index, r, has been widely tested and applied in many countries and regions around the world whose rainfall intensity is characterized mainly as moderate to high 915. The data obtained was analyzed using raster distribution from arcgis 10. The following two methods are widely used for computing the erosivity of rainfall. Rainfall erosivity index for the ghana atomic energy. Investigating rainfall erosivity indices in arid and semiarid climates of iran.
Wischmeier and smith 6 developed the first iteration of the modern rainfall erosivity index used today 2,6,7 and has also proved ei 30 s applicability in the loess plateau of china during the. Rainfall erosivity factor for india using modified fourier. This index is more effective in accounting for event soil losses at some locations where the ei 30 index does not work well fig. Rainfall erosivity r factor has been determined for sierra leone using monthly precipitation data covering 196020 using fournier fi and modified fournier mfi indices. In computing the rainfall erosivity factor, the maximum 30min rainfall intensities for the storm and heavy storm events are generally computed on the basis of hyetograph data or highresolution rainfall. Investigating rainfall erosivity indices in arid and semiarid climates of iran 366 th e subject of rainfall erosivity has been studied worldwide, and various properties of raindrops, such as intensity, velocity, size, and kinetic energy, are among the most frequently used parameters to develop erosivity indices. The period of construction activity begins at initial earth disturbance and ends with final stabilization. Rainfall and runoff erosivity r factor student materials. The results show an increase in the future periods of. Monthly variations of rainfall erosivity r factor in. Rainfall erosivity index pdf rainfall erosivity is defined as the aggressiveness of the rain to punyavachanam mantras pdf cause erosion. Estimated average annual values of the rainfall erosion index in hawaii 7. Download a pdf of all web pages for the student materials. Average annual values of the rainfall erosion index map between pages 6 and 7 2.
The rainfall erosivity r factor of the revised universal soil loss equation rusle was used to determine rainfall erosivity. The subject of rainfall erosivity has been studied worldwide, and. The accuracy of the rfactor depends greatly on the time interval at which precipitation is recorded. The study showed that there is a decreasing trend in annual rainfall. Rainstorm plays a paramount role in surface sealing, runoff and erosion process. Epa rainfall erosivity factor calculator webpage author environmental protection agency. Investigating rainfall erosivity indices in arid and. Determination of rainfall erosivity index r for imo state.
Erosivity is used around the world for assessing and predicting rates of soil erosion on agricultural lands. Estimating the rainfall erosivity factor from monthly. The purpose of this study is to assess monthly variations of rainfall erosivity in shida kartli region from the rusle rfactor, based on the best available datasets. The results presented here provide the much needed guidance to remove ambiguities regarding the rainfall erosivity factor in the indian context. Worldclim data was used as the present baseline precipitation scenario for the study area. Arnoldus 1980 attempted to correlate this index with the known values of the rainfall erosivity factor for 164 rainfall stations in the united states and 14 stations in west africa. To use the rainfall erosivity factor calculator to determine your eligibility for the lew, you will need your projects location either latitudelongitude or address and the estimated start and end dates of construction. Usda developed the erosivity index table ei table, provided here in table 1, to show how the annual erosivity factor is distributed throughout the year in twoweek increments. The erosivity factor in the universal soil loss equation usle provides an effective means of evaluating the erosivity power of rainfall. Estimation of rainfall erosivity using 5 southwest watershed.
Rainfall erosivity estimation for sierra leone using non. Pdf a scenario of rainfall erosivity index research researchgate. It is estimated as the average annual value of the sum of all erosive events ei 30 over a period of many years. The new general construction permit 20090009 includes the option allowing small construction site 1 and 5. He also showed, that the fm index is a good approximation of r rainfall erosivity to which it is linearly correlated.
Global rainfall erosivity esdac european commission. Pdf determination of rainfall erosivity index r for imo state. Figure 1 pluviometric stations in espirito santo state where synthetic rainfall series were generated. Evaluation of annual rainfall erosivity index based on daily. Fm takes into account the seasonal variation in the precipitation, analyzing data on fm, for different european regions bergsma, 1980. The global erosivity map is publicly available and can be used by other research groups to perform national, continental and global soil erosion modelling. On the other hand, researchers used the summation of halfmonth erosivity index method derived from daily rainfall rate greater than mmday 1 to evaluate the annual rainfall erosivity. A single index of rainfall erosivity that can measure the composite effect of various rainstorm characteristics on soil erosion is highly desirable for predicting soil loss 1, 2. Detailed instructions for calculating a project r factor are provided later in this fact sheet. Statistical determination of rainfallrunoff erosivity. Published environmental protection agency, date not provided. Kinetic energy of rainfall expressed in metric tonmeters per hectare per centimeters of rain.
Rainfall erosivity is the potential ability for rainfall to cause soil loss. Estimating the rainfall erosivity factor from monthly precipitation data in the madrid region spain. In addition, the exclusion from npdes stormwater permitting is available on a developmentwide basis only, not for individual filings, phases, or other portions of a larger common plan development or sale. In other words, the estimation model based on the annual precipitation data provides a reliable means of predicting the longterm annual rainfall erosivity in southern. Estimation of rainfall erosivity using 5 to 60minute fixedinterval rainfall data from china s. The purpose of this study was to estimate the rainfall erosivity index for the ghana atomic energy commission site in order to compute the surface erosion rate. Investigating rainfall erosivity indices in arid and semiarid. The rainfall erosivity factor r is defined as the average annual sum of individual storm erosion index values, e, where e is the total storm kinetic energy per. Construction rainfall erosivity waiver fact sheet pdf 12 pp, 3 mb. Monthly rainfall data, for the period 20032012 were used to compute annual rainfall erosivity indices for the site, using the modified fournier index. Rainfall erosivity indicates the potential of a storm to erode soil. Rainfall erosivity index in response to soil loss under.