Erosion control index and notes kirkland, washington. Erosion hazard zone delineation and development guidelines. Erosion and sediment control workshop revised universal. Feb 14, 20 this video will help you better understand the problems associated with wind erosion of soil. The area and soil loss account for 53% and 97% of the totals, respectively. Erosion questions and answers what type of erosion are we talking about. Method factsheet rusle revised universal soil loss. The usda soil conservation service has used the equation extensively to plan wind erosion. Geomorphologists and other earth scientists usually consider wind erosion as a specific subdiscipline of a more broad study of aeolian also spelled eolian processes.
State the operational and technical definitions of a buffer. The k factor is based on the type of soil that is in the area you are investigating. Application of the universal soil loss equa tion to. For many states, these have already been populated.
Comparative study of different erosion models in an. The boundaries of the clearing limits shown on this plan shall be set by survey and clearly flagged in the field by a clearing control fence prior to construction. The wind erosion equation is used to predict soil loss by wind forces from specific field areas. The universal soil loss equation usle is widely used to estimate erosion in the united states and foreign countries. Major constraints of rweq for application in the sahel were the required noneroding boundary and the fact that rweq assumes a more or less homogeneous field. Read more why should we care about erosion along stream banks and along shorelines. Estimation of sediment yield with musle and monitoring. Comparative study of different erosion models in an eulerianlagrangian frame using open source software a.
Soil erosion is a growing problem in central chile, particularly in coastal dry lands, where it. Liquid droplet erosion this form of ersoion happens due to the formation of very high pressures and stresses at the point where the liquid droplets contact the pipe wall. Wind erosion prediction system weps a processbased model is now used by nrcs and weq is no longer actively supported by usda nrcs for conservation planning. Some of the erosion mechanisms are described below. Department of agriculture, agricultural research service, ars77, pp.
An alternative to api 14e erosional velocity limits for sandladen flow velocity ve to that established by the recommended practice api rp 14e based on an empirical constant c. Particle dynamics are described in terms of suspension, saltation, surface creep, abrasion, sorting and threshold conditions. Standard methods for wind erosion research and model development. Geographic information system gis represents a modem tool that analyzes and creates maps to solve wind erosion problems. The universal soil loss equation usle is a widely used mathematical model that describes soil erosion processes erosion models play critical roles in soil and water resource conservation and nonpoint source pollution assessments, including. Erosion submodel 2 abstract 3 an overview of the tasks of the erosion submodel of the wind 4 erosion prediction system weps is presented with emphasis on 5 the prediction equations for the saltationcreep and suspension 6 components. This point is commonly referred to as the minimum fluidization velocity, mf u. The wind erosion equation was developed by the late dr. Wind erosion equation weq does not predict wind erosion where erosion is observed in some areas.
Thermal erosion is the result of melting and weakening permafrost due to moving water. The l and s factors are usually considered together and are measures of the length. This assumption typicall y allows for a simplified, yet accurate analysis of the given conditions. Erosion by wind soil and water conservation management. Appendix c small construction waivers and instructions. Pdf wind erosion refers to the detachment, transport, and deposition of sediment by wind. Why is wind erosion more important in arid regions than humid areas. Jager 1994 used the empirical universal soil loss equation usle to assess soil erosion risk in badenwurttemberg germany. Mapping potential soil erosion in east africa using the universal soil. Ls factor was determined these, the one that is better suitable for combination by the geographic information system is the theoretical relationship raster calculations in arcmap arisen on stream power theory.
Water that moves over earths surface when it rains is called runoff. Excessive erosion is often caused by human activities, such as deforestation, road construction and intensive farming. Wind erosion refers to the detachment, transport, and deposition of sediment by wind. Chapter 16 worksheet 1 buffers and the hendersonhasselbalch equation. The equation is designed to serve the twofold purpose of providing a tool to i determine the potential erosion from a particular field, and ii determine what field conditions of soil cloddiness, roughness, vegetative cover, sheltering by barriers, or width and orientation of field are necessary to reduce potential erosion to a tolerable amount. Wind erosion can be a threat to agriculture productivity and the sustainability of the earths natural resources. The computer solution is similar to the manual solution but requires a certain minimum amount of information, which can be supplied easily on form 1 for computer solution of wind erosion equation fig. We are talking about the loss of land caused by moving water in rivers, lakes and the ocean. Universal soil erosion equation beginning 10,000 years ago, during a period called the neolithic, people started farming in jordan. Estimating water erosion and sediment yield with gis.
Wind erosion modelling in a sahelian environment sciencedirect. Types and forms of erosion by water and by wind anne x 1 1. This lesson covers the topic of soil erosion using the revised universal soil loss equation rusle. Dempster 1mechanical and aerospace engineering, university of strathclyde, glasgow, uk alejandro. The wind erosion equation the wind erosion equation weq erosion model is designed to predict longterm average annual soil losses from a field having specific characteristics. Soil erosion soil erosion is the detachment and movement of soil material.
The weq is described by the general functional relationship efunction of i, c, k, l, v, where e is the potential average annual soil loss in tons per acre per year. Soil erosion assessment using gis and revised universal. Here, the abrasion coefficient is defined as the abraded soil loss per. The kinematic runoff and erosion model kineros is an eventoriented, physically based model describing the processes of interception, infiltration, surface runoff, and erosion from. Vocabulary abrasion when a rocks surface are reduced in size by friction when particles are transported by wind. Wind erosion is widespread on agricultural land in the. Application of the universal soil loss equa tion to rangelands on a perstorm basis douglas j. The weq wind erosion equation was reported by woodruff and siddoway in 1965. For sets a and b in z 2 binary image, erosion of a by b is denoted by a. Erosion mechanism can be a combination of several factors in flowing fluids. E the predicted average annual soil loss in tons per acre per year. Other than how people use the land, four factors that determine the amount of runoff in an area are.
The factor values for the equations used in the soilloss equations are those in effect as of january 1, 1990. Abstract the wind erosion equation weq was used for several decades for predicting soil loss by wind erosion, but few systematic studies on. This project would increase the understanding of the waterborne soil erosion directly related to river systems and the gis combined rusle model. Archived wind erosion equation weq weq an empirical wind erosion prediction model was previously used and maintained by usda nrcs.
Appendix c small construction waivers and instructions these waivers are only available to stormwater discharges associated with small construction activities i. Wind erosion quantitative assessment a gis version of the revised. Gifford abstract the universal soil loss equation was evaluated in rangeland conditions on a perstorm basis utilizing rainfall simulator data. Method factsheet rusle revised universal soil loss equation introduction the revised universal soil loss equation rusle is an empirical erosion model recognised as a standard. The r factor is based on rainfall and runoff, while k is the soil erodibility factor and depends on the type of soil. The amount of rain it receives, vegetation plants there, type of soil, shape of the land. The first wind erosion equation was a simple exponen.
It is the result of nearly 30 years of research to determine the primary variables or factors that influence erosion of soil by wind. You can calculate the soil erosion rate by measuring the loss of soil mass over a specific time period. Depending on the local landscape and weather conditions, erosion may be very slow or very rapid. Erosion can destroy property, human development homes and businesses, and most. Water erosion is very simplistically speaking caused by rainfall, river flow, waves wave action, hydraulic action and abrasion, corrosion, glacier movement, thawing, etc. The equation has been used widely for both of these applications. Mamassis 2 1hydroexigiantiki consulting engineers, 3 evias str. There is a need for more information about wind erosion than just rotational average tonsacreyear we get now.
The five types of water erosion and techniques for minimizing them are outlined in table 11. When the gas velocity is high enough that the drag force on the particles equals the weight of the particles i. Standard methods for wind erosion research and model development protocol for the national wind erosion research network by nicholas p. Value 1 this form of erosion is no longer visible after cultivation ploughing, hoeing etc. Wind erosion is a natural process where the soil is moved, carried, and transported by the force of the wind from one place to another. Spatial estimation of soil erosion risk using rusle. The equation is a r x k x l x s x c x p and multiplies various factors to arrive at the annual erosion rate. About the universal soil loss equation the universal soil loss equation usle is hailed as one of the most significant developments in soil and water conservation in the 20 thcentury. The process may be natural or accelerated by human activity. Modified as caltrans rusle2, this software is streamlined for use on large, roadway construction projects and includes commonly used best management practices bmps. An empirical model developed for agricultural applications, the universal soil loss equation usle, predicts soil loss resulting from sheet and rill erosion. It is an empirical technology that has been applied around the world to estimate soil erosion by raindrop impact and surface runoff.
Wind is the weakest agent in shaping the land, but can be powerful in shaping the land in areas where there are few plants to hold the soil in place. The weq was the only model available to plan wind erosion control systems until the revised wind erosion equation rweq was released. The revised wind erosion equation rweq poorly predicted maximum mass transport and so spatial predictions of mass transport were underestimated. The state agronomist or erosion prediction specialist will need to set up the wind climate data, crop data and operation tillage files.
Ap propriate data are entered in the blanks on form 1 and appro. Large groups of people lived together in lowland and hillside landscapes that they had cleared of trees and. The above equation is applied to predict the sediment yield, when source of sediment in watershed is the sheet erosion only, but when floodplain channel scour and gully erosion are also there as sediment source to yield the sediment load from the watershed, then the equation. This article throws light upon the ten main factors affecting wind erosion. This cali bration of a portable wind tunnel was used to evaluate ridge roughness equivalent for many field surfaces. A buffer is a solution that resists changes in ph upon the addition of a small amount of strong acid or strong base. The wind erosion prediction system weps was developed by a multidisciplinary team of usda scientists in collaboration with other agencies and private cooperators in response to customer. Wind erosion equation weq recent changes to weq a slide presentation download the powerpoint presentation 1. Uncertainty and sensitivity analyses of the modified wind erosion.
Rainfall erosivity factor r the erosivity factor r in the usle equation is accounted for by the rainfallrunoff, it is considered as a driver of soil erosion processes. Weq utilized the available technology to estimate annual soil erosion with different management systems. Predicting soil loss associated with modern land use is based on guidelines developed from research information in combination with additional expe. Aerodynamic particle size multipliers for equation 2 30 m equation is designed to serve the twofold purpose of providing a tool to i determine the potential erosion from a particular field, and ii determine what field conditions of soil cloddiness, roughness, vegetative cover, sheltering by barriers, or width and orientation of field are necessary to reduce potential erosion to a tolerable amount. As the operator of a small construction activity, you may be able to qualify for a waiver in lieu of needing to obtain coverage under this general permit based on. Weq was developed using laboratory and field wind tunnel data, but had little supporting field data of erosion from. This information is provided by the usda engineering and wind erosion research unit in cooperation. Using this tool, wind erosion equation weq acquires a new dimension to evaluate soil loss caused by wind erosion that can be identified exactly for certain field in the selected area. Rusle k values california state water resources control. These documents should be referred to and used for all data recording and submission as part of network activities. In order to be transported, threshold velocity of the wind is needed. The wind erosion equation weq is the primary wind erosion prediction technology currently in use in the united states 23, 51. Degrees indicate deviation of the prevailing wind erosion direction from northsouth and percentages indicate per cent of erosion that occurs along that direction.
Ths area accounts for 29% of the total area and contributes to 2% of the total soil loss. The revised universal soil loss equation, version 2 rusle2 is an advanced, userfriendly software model that predicts longterm, average annual erosion by rainfall. However, watergenerated erosion is the most damaging factor, especially in developing areas. Regon 3 includes most of the agricul tural zones along both sides of the lawyers creek. To predict future soil erosion due to water, scientists developed the universal soil loss equation, or usle. Basic wind erosion processes are discussed under the major headings of soil particle dynamics, particle flow rates, and principles and general strategies of control. It is also transitory and would be significant only where.
It is used for removing irrelevant size details from a binary image. Erosion and dilation in digital image processing buzztech. Natural erosion has sculptured landforms on the uplands and built landforms on the lowlands. Revised universal soil loss equation, as a tool for assessing erosion risk at a site under different management conditions. Understanding the factors that effect the erosion process enables us to make useful predictions about the extent and consequences of onsite erosion. A gis version of the revised wind erosion equation rweq was developed in jrc to model. A estimate of soil loss rate in tonshectareyear k soil erodibility factor r rainfall factor ls slope factor c crop management factor. Wind erosion weps soil erosion by wind is a serious problem in the united states and the world. Lyon, extension dryland crops specialist, and john a. This workshop is designed to guide participants through the blue book so they can apply it to their plans and sites. The erosion of surface soil by wind renders the soil less productive by removing the most fertile part of the soil, namely. In the following discussion, example problems and subsequent sections, the pipe is assumed to be flowing full.
C climatic characterization of windspeed and surface soil moisture expressed as a percentage. Use of the universal soil loss equation to predict erosion in west africa. This page provides access to all manuals, data recording sheets and documentation for the national wind erosion research network. Pi erosion potential corresponding to the observed or probable fastest mile of wind for the ith period between disturbances, gm2 the particle size multiplier k for equation 2 varies with aerodynamic particle size, as follows. Pdf an introduction to the wind erosion prediction system. Evaluation of soil loss estimation using the rusle model. Processes and principles of erosion and sedimentation. We use principles of the universal soil loss equation usle and its reformulations to make a qualitative. This nebguide discusses how wind erosion occurs and presents methods for reducing wind erosion on land devoted to crop production. Soil science society of america journal abstract a wind.
Estimation of soil erosion risk using the universal soil. The shear on the pipe is related to pressure loss of the pipe as per below equation. Erosion and changes in the form of river banks may be measured by inserting metal rods into the bank and marking the position of the bank surface along the rods at different times. It is the set of all points z such that b, shifted or translated by z, is contained in a. It is a dynamic, physical process where loose, dry, bare. A case study for tsiknias dam at lesvos island in greece. It is the potential for soil loss from a wide, level, unsheltered, isolated field with a bare, smooth, loose and uncrusted surface.