Download or read book Mathematical Modeling of Soil Erosion by Rainfall and Shallow Overland Flow written by Tingting Zheng and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: New analytical and numerical solutions are developed to both the kinematic approximation to the St Venant equations and the Hairsine-Rose (HR) soil erosion model in order to gain a better physical understanding of soil erosion and sediment transport in shallow overland flow. The HR model is unique amongst physically based erosion models in that it is the only one that: considers the entire distribution of the soil s sediment size classes, considers the development of a layer of deposited non-cohesive sediment having different characteristics to the original underlying cohesive soil and considers separately the erosion processes of rainfall detachment, runoff entrainment and gravitational deposition. The method of characteristics and the method of lines were used to develop both the analytical and numerical solutions respectively. These solutions were obtained for boundary and initial conditions typical of those used in laboratory flume experiments along with physically realistic constant and time dependent excess rainfall rates. Depending on the boundary and initial conditions, interesting new solutions of the kinematic wave equation containing expansion waves, travelling shocks as well as solutions which split into an upslope and downslope drying profiles were found. Numerical solutions of the HR model were applied to the experimental flume data of Polyakov and Nearing (2003) obtained under flow conditions which periodically cycled between net erosion and net deposition conditions. While excellent agreement was found with suspended sediment data, the analysis suggested that an additional transport mechanisms, traditionally not included in soil erosion models, was occurring. While the inclusion of bed-load transport improved the ii overall model prediction, it was still not sufficient. Subsequent asymptotic analysis then showed that the interaction of the flow with an evolving bed morphology was in fact far more important than bed load transport. A very interesting finding from this work showed that the traditional criterion of validating sediment transport model based solely on suspended sediment data was not sufficient as reliable predictions could be obtained even when important transport mechanisms were neglected. Experimental plots of sediment discharge or suspended sediment concentration against water discharge in overland flow have been shown to contain significant hysteresis between the falling and rising limbs of the discharge hydrograph. In the final Chapter, the numerical solution developed for the complete system of soil erosion and kinematic flow was used to show that it was possible for the HR model to simulate three of the four hysteresis loops identified in the literature. Counter clock-wise loops, clock-wise loops and figure 8 loops could all be produced as a result of starting with different initial conditions, being mi(x; 0) = 0, mi(x; 0) = pimt and mi(x; 0) = 0:5pimt respectively. This is the first time that these types of hysteresis loops have been produced by any erosion model. The generation of these hysteresis loops are physically explainable in terms of sediment availability and is consistent with data obtained on the field scale.
Download or read book Modelling Soil Erosion by Water written by John Boardman and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 552 pages. Available in PDF, EPUB and Kindle. Book excerpt: TO THE MODEL EVALUATION 1. MODELLING SOIL EROSION BY WATER l 2 John Boardman and David Favis-Mortlock 1 School of Geography and Environmental Change Unit Mansfield Road University of Oxford Oxford OX1 3TB UK 2 Environmental Change Unit University of Oxford 5 South Parks Road Oxford OX1 3UB UK Introduction This volume is the Proceedings of the NATO Advanced Research Workshop 'Global Change: Modelling Soil Erosion by Water', which was held on II-14th September 1995, at the University of Oxford, UK. The meeting was also one of a series organised by the IGBP 1 GCTE Soil Erosion Network, which is a component of GCTE's Land Degradation Task (3.3.2) (Ingram et aI., 1996; Valentin, this volume). One aim of the GCTE Soil Erosion Network is to evaluate the suitability of existing soil erosion models for predicting the possible impacts of global change upon soil erosion. Due to the wide range of erosion models currently, in use or under development, it was decided to evaluate models in the following sequence Favis-Mortlock et al., 1996): • field-scale water erosion models • catchmenr-scale water erosion models • wind erosion models • models with a landscape-scale and larger focus. As part of this strategy, the first stage of the GCTE validation of field-scale erosion models was carried out at the Oxford NATO-ARW. I A list of Acronyms fonns Appendix A.
Download or read book Handbook of Erosion Modelling written by R. P. C. Morgan and published by John Wiley & Sons. This book was released on 2016-04-13 with total page 608 pages. Available in PDF, EPUB and Kindle. Book excerpt: The movement of sediment and associated pollutants over thelandscape and into water bodies is of increasing concern withrespect to pollution control, prevention of muddy floods andenvironmental protection. In addition, the loss of soil on site hasimplications for declining agricultural productivity, loss ofbiodiversity and decreased amenity and landscape value. The fate ofsediment and the conservation of soil are important issues for landmanagers and decision-makers. In developing appropriate policiesand solutions, managers and researchers are making greater use oferosion models to characterise the processes of erosion and theirinteraction with the landscape. A study of erosion requires one to think in terms ofmicroseconds to understand the mechanics of impact of a singleraindrop on a soil surface, while landscapes form over periods ofthousands of years. These processes operate on scales ofmillimetres for single raindrops to mega-metres for continents.Erosion modelling thus covers quite a lot of ground. This bookintroduces the conceptual and mathematical frameworks used toformulate models of soil erosion and uses case studies to show howmodels are applied to a variety of purposes at a range of spatialand temporal scales. The aim is to provide land managers and otherswith the tools required to select a model appropriate to the typeand scale of erosion problem, to show what users can expect interms of accuracy of model predictions and to provide anappreciation of both the advantages and limitations of models.Problems covered include those arising from agriculture, theconstruction industry, pollution and climatic change and range inscale from farms to small and large catchments. The book will alsobe useful to students and research scientists as an up-to-datereview of the state-of-art of erosion modelling and, through aknowledge of how models are used in practice, in highlighting thegaps in knowledge that need to be filled in order to develop evenbetter models.
Download or read book Soil Erosion written by Rorke Bryan and published by Destedt, West Germany : Catena Verlag. This book was released on 1990 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface seal development in relation to rainstorm intensity. Experimental study and modelling of soil surface crusting processes. Fabric analysis of surface crusts developed under simulated rainfall on loess soils, China. Temporal variations in soil erodibility. Modelling erosion by rain-impacted flow. Solute transport and wind action in relation to overlanc flow and water erosion. Initiation of motion of gravels in concentrated overland flow: cohesive forces and probability of entrainment. Inception of sediment transport in shallow overland flow. Knickpoint evolution in rillwash. A one-dimensional model for rill inter-rill interactions. Threshold conditions for thalweg gulliyng with special reference to loess areas. Interpreting the role of soil strenght in erosion processes. Grain size catenas and hillslope evolution. Quantification of soil redistribution in cultivated fields, using Caesium-137, outlook, Saskatchewan. The catastrophic nature of seepage scald formation in southeastern Australia.
Download or read book Soil Erosion written by Jürgen Schmidt and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: Accelerated degradation of soils and surface waters produce increasing problems in many parts of the world. Within this context, the book addresses the topic Application of Physically Based Soil Erosion Models in order to present some essential tools for improving land-use strategies and conservation measures. Over the last 20 years, the need for more accurate assessments of soil losses and sediment yields has led to the development of some highly complex, process-based soil erosion models. In 14 papers, specialists from 5 European countries, the USA and Brazil report on practical applications of these models and give insight into the latest developments. This book will help to implement state-of-the-art soil erosion prediction technologies within soil and water conservation planning and assessment. Hence, the book should be of special interest to agricultural and environmental engineers, hydrologists, soil scientists and geoscientists.
Download or read book The Effects of Spatially varying Soil Properties on Soil Erosion written by and published by . This book was released on 1988 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this study is to investigate the effects of only rainfall excess generation on erosion. We illustrate the effects of spatial variation in saturated hydraulic conductivity (K/sub s/) on the spatial and temporal distributions of erosion resulting from overland flow. We use this as a basis to demonstrate the potential for bias in parameters estimated from field data. Mathematical modeling of soil erosion must include surface runoff the dominant transport mechanism. Rainfall excess when routed over the surface, produces a distribution of velocities and depths in response to surface, roughness, surface form or microtopography, and available water. The spatial distribution of velocities and depths strongly affects sediment delivery as well as the re-distribution of soil on the hillslope. 23 refs., 12 figs., 3 tabs.
Download or read book Mathematical Modeling of Ephemeral Gully Erosion written by Vladimir Rustemovich Karimov and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: As the world faces an increasing demand for food due to the growing global population and the pernicious effects of land degradation, there is a need to overcome this challenge by using sustainable management practices for agricultural productions. One of the problems, which sustainable agriculture seeks to address, is the loss of topsoil due to soil erosion. Changing weather patterns also contribute to the average annual rainfall across the globe with an excess precipitation, which creates runoff and causes soil erosion. One of the significant yet less studied types of soil erosion is ephemeral gully erosion. Formed by the concentrated overland flow during intensive rainfall events, ephemeral gullies are channels on agricultural fields that can be removed by tillage operations but appear at the same location every year. Even though simplified ephemeral gully models estimate soil losses, they do not account for complicated hydrological and soil erosion processes of channel formations. The purpose of this research work is to investigate sediment sources and develop tools that can predict ephemeral gully erosion more efficiently. To achieve this goal, an experimental study was conducted on an agricultural field in central Kansas by tracking channel development, monitoring soil moisture content, and recording the amount of rainfall. Runoff and sediment loads from contributing catchment and critical and actual shear stresses were estimated by the computer model, and conclusions were made on the effect of saturation dynamics on the erosion processes. Furthermore, a two-dimensional subsurface water flow and soil erosion model was developed with the variable soil erodibility parameters which account for the subsurface fluxes and the effects on the soil detachment process. The model was applied to study the impacts of variable soil erodibility parameters on the erosion process for different soils and various antecedent soil moisture conditions. Also developed to estimate the soil losses at the field scale was an integrated spatially-distributed ephemeral gully model with dynamic time-dependent channel development. The model showed good fit by matching the experimental data. The results from this work can be used to advance the research of soil erosion prediction from concentrated flow channels and ephemeral gullies formed on agricultural fields.
Download or read book Modeling of Soil Erosion and Sediment Transport written by Vlassios Hrissanthou and published by . This book was released on 2020-09-03 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Special Issue entitled "Modeling of Soil Erosion and Sediment Transport" focuses on the mathematical modeling of soil erosion caused by rainfall and runoff at a basin scale, as well as on the sediment transport in the streams of the basin. In concrete terms, the quantification of these phenomena by means of mathematical modeling and field measurements has been studied. The following mathematical models (software) were used, amongst others: AnnAGNPS, SWAT, SWAT-Twn, TUSLE, WRF-Hydro-Sed, CORINE, LCM-MUSLE, EROSION-3D, HEC-RAS, SRC, WA-ANN. The Special Issue contains 14 articles that can be classified into the following five categories: Category A: "Soil erosion and sediment transport modeling in basins"; Category B: "Inclusion of soil erosion control measures in soil erosion models"; Category C: "Soil erosion and sediment transport modeling in view of reservoir sedimentation"; Category D: "Field measurements of gully erosion"; Category E: "Stream sediment transport modeling". Most studies presented in the Special Issue were applied to different basins in Europe, America, and Asia, and are the result of the cooperation between universities and/or research centers in different countries and continents, which constitutes an optimistic fact for the international scientific communication.
Download or read book Landscape Erosion and Evolution Modeling written by Russell S. Harmon and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: Landscapes are characterized by a wide variation, both spatially and temporally, of tolerance and response to natural processes and anthropogenic stress. These tolerances and responses can be analyzed through individual landscape parameters, such as soils, vegetation, water, etc., or holistically through ecosystem or watershed studies. However, such approaches are both time consuming and costly. Soil erosion and landscape evolution modeling provide a simulation environment in which both the short- and long-term consequences of land-use activities and alternative land use strategies can be compared and evaluated. Such models provide the foundation for the development of land management decision support systems. Landscape Erosion and Evolution Modeling is a state-of-the-art, interdisciplinary volume addressing the broad theme of soil erosion and landscape evolution modeling from different philosophical and technical approaches, ranging from those developed from considerations of first-principle soil/water physics and mechanics to those developed empirically according to sets of behavioral or empirical rules deriving from field observations and measurements. The validation and calibration of models through field studies is also included. This volume will be essential reading for researchers in earth, environmental and ecosystem sciences, hydrology, civil engineering, forestry, soil science, agriculture and climate change studies. In addition, it will have direct relevance to the public and private land management communities.
Download or read book MATHEMATICAL MODELS Volume II written by Jerzy A. Filar and published by EOLSS Publications. This book was released on 2009-09-19 with total page 510 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mathematical Models is a component of Encyclopedia of Mathematical Sciences in the global Encyclopedia of Life Support Systems (EOLSS), which is an integrated compendium of twenty one Encyclopedias. The Theme on Mathematical Models discusses matters of great relevance to our world such as: Basic Principles of Mathematical Modeling; Mathematical Models in Water Sciences; Mathematical Models in Energy Sciences; Mathematical Models of Climate and Global Change; Infiltration and Ponding; Mathematical Models of Biology; Mathematical Models in Medicine and Public Health; Mathematical Models of Society and Development. These three volumes are aimed at the following five major target audiences: University and College students Educators, Professional practitioners, Research personnel and Policy analysts, managers, and decision makers and NGOs.
Download or read book Mechanics of Soil Erosion from Overland Flow Generated by Simulated Rainfall written by Mustafa Kilinc and published by . This book was released on 1973 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Sediment Transport Capacity for Soil Erosion Modelling at Hillslope Scale written by Mazhar Ali and published by . This book was released on 2012 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Rainfall Erosivity in Soil Erosion Processes written by Gianni Bellocchi and published by MDPI. This book was released on 2020-04-21 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book gathers recent international research on the association between aggressive rainfall and soil loss and landscape degradation. Different contributions explore these complex relationships and highlight the importance of the spatial patterns of precipitation intensity on land flow under erosive storms, with the support of observational and modelling data. This is a large and multifaceted area of research of growing importance that outlines the challenge of protecting land from natural hazards. The increase in the number of high temporal resolution rainfall records together with the development of new modelling capabilities has opened up new opportunities for the use of large-scale planning and risk prevention methods. These new perspectives should no longer be considered as an independent research topic, but should, above all, support comprehensive land use planning, which is at the core of environmental decision-making and operations. Textbooks such as this one demonstrate the significance of how hydrological science can enable tangible progress in understanding the complexity of water management and its current and future challenges.
Download or read book Rainfall Simulation Runoff and Soil Erosion written by Jan de Ploey and published by . This book was released on 1983 with total page 584 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Selected Water Resources Abstracts written by and published by . This book was released on 1991 with total page 898 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modelling Soil Erosion Sediment Transport and Closely Related Hydrological Processes written by Wolfgang Summer and published by IAHS Press. This book was released on 1998 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Selected Water Resources Abstracts written by and published by . This book was released on 1991 with total page 896 pages. Available in PDF, EPUB and Kindle. Book excerpt:
