A mathematical erosion model to simulate soil losses in agricultural watersheds

A deterministic conceptual model which simulates detachment, entrainment, transport and deposition of eroded soil particles by rainfall impact and flowing water is presented. Both upland and channel phases of sediment yield are incorporated into the erosion model. The algorithms for the soil erosion and sedimentation process including land and crop management effects are taken from the literature and then solved using a digital computer;The erosion model is used in conjunction with the modified Kentucky Watershed Model which simulates the hydrologic characteristics from watershed data. The two models are linked together by using the appropriate computer code. The watershed and erosion model provides the streamflow rate and suspended sediment yield at each time step;Calibrations for both the watershed and erosion model parameters are made by comparing the simulated results with actual field measurements in the Four Mile Creek watershed near Traer, Iowa using 1976 and 1977 water year data. Two water years, 1970 and 1978, are used as test years for model verification;There is good agreement between the mean daily simulated and recorded streamflow and between the simulated and recorded suspended sediment load. A correlation coefficient of approximately 80% is obtained between the recorded data and the simulated results from both the watershed and erosion models. The results obtained demonstrate the validity of the model and its ability to predict soil loss and sediment yield from small agricultural watersheds;Futhermore, by further modification and expansion with additional data, the watershed and erosion model developed through this study can be used as a planning tool for watershed management and for solving non-point pollution problems

Simulating the characteristics of droughts in Southern Africa

Includes bibliographical references.Drought is widely considered as one of the most devastating natural disasters in the world. In particular, drought is a big threat in Southern Africa because the economy of most of the population in the region is based on rain-fed agriculture. Previous studies have projected that global warming may enhance the frequency and intensity of droughts over Southern Africa in the future. However, the credibility of this projection depends on the ability of the global and regional climate models (GCMs and RCMs) in simulating the characteristics of drought. This thesis presents the characteristics of the Southern African droughts and evaluates the capability of global and regional climate models in simulating these characteristics. The thesis used a multi-scaled standardized drought index (called standardized precipitation evapo-transpiration index, SPEI) in characterizing droughts at 3- and 12-month scales over Southern Africa. The spatial patterns of the droughts are identified using the principal component analysis (PCA) on the SPEI, while the temporal characteristics of the drought patterns are studied using wavelet analysis. The relationship between each drought pattern and global SSTs (and climate indices) is quantified using correlation analysis and wavelet coherence analysis. The study uses correlation analysis to quantify the capability of the models in simulating the drought patterns

Structural Health Monitoring (SHM) and Determination of Surface Defects in Large Metallic Structures using Ultrasonic Guided Waves

Ultrasonic guided wave (UGW) is one of the most commonly used technologies for non-destructive evaluation (NDE) and structural health monitoring (SHM) of structural components. Because of its excellent long-range diagnostic capability, this method is effective in detecting cracks, material loss, and fatigue-based defects in isotropic and anisotropic structures. The shape and orientation of structural defects are critical parameters during the investigation of crack propagation, assessment of damage severity, and prediction of remaining useful life (RUL) of structures. These parameters become even more important in cases where the crack intensity is associated with the safety of men, environment, and material, such as ship’s hull, aero-structures, rail tracks and subsea pipelines. This paper reviews the research literature on UGWs and their application in defect diagnosis and health monitoring of metallic structures. It has been observed that no significant research work has been convened to identify the shape and orientation of defects in plate-like structures. We also propose an experimental research work assisted by numerical simulations to investigate the response of UGWs upon interaction with cracks in different shapes and orientations. A framework for an empirical model may be considered to determine these structural flaws

Effects of Stream Channel Improvements on Downstream Floods

This report presents a self-calibrating watershed model for predicting the effect of channel improvements on downstream floods. The model is called MOPSET because it is a modified version of OPSET developed several years ago at the University of Kentucky. OPSET is a computerized procedure for determining an optimum set of parameter values by matching synthesized flows with recorded flows. Major modifications include the replacement of the modified Muskingum method of channel routing by a kinematic finite difference method, the division of the watershed into a number of segments, and the inclusion of a storage routing procedure to take care of any reservoirs or flood control structures located in the watershed. The computer program is well documented and can be used not only as a flood predicting model but also as a general model for hydrologic simulations. The model was applied to three different watersheds in Kentucky. It was found that the optimum set of parameter values obtained automatically by the model was not unique and might not yield the most desirable solution. For this reason, new features were added so that the user can exercise his judgment in selecting the most desirable parameter values. The synthesized flows obtained from these watersheds are presented and compared with the recorded flows. The effects of channel improvements, flood control structures, and routing procedures on the synthesized flows are discussed

Proceedings of the SUPTM 2022 conference

This book includes the proceedings of the 1st international Conference on Future Challenges in Sustainable Urban Planning & Territorial Management celebrated on January 17-19, 2022. Urban planning is an essential tool in our global society's journey towards sustainability. This tool is as important as the territorial management to execute the plans. Both, planning and management, must be efficient to achieve the goal of sustainability inside the general framework of Sustainable Development Goals of United Nations. It does not exist any B planet so, identify urban & territorial challenges in our territories such reaching sustainable mobility, diagnose natural hazards and control land resource consumption is mandatory for our XXI century generation. Planning land uses compatibles with the ecosystem services of territory and manage them by public-private cooperation systems is a greatly challenge for our global society. Human activities do not have very frequently among their objectives to maintain ecosystem services of territory. Therefore, this field of research must help to guarantee the maintenance of natural resources, also called Natural Capital, necessary for social and economic activities of our global society. This conference aims to be a space to share research works, ideas, experiences, projects, etc. in this field of knowledge. We want to put in value that planning and management are subjects that include technological and social matters and their own methodologies. Laws, rules and cultures of different countries around the world are or can be very diverse. But the planet is only one. Technologies are shared, methodologies to analyze territories are also communal to share experiences about the global goal of sustainability, so these events are a necessary way to build our joint future. We trust that the success of this first edition of the SUPTM conference (which has been attended by more than 200 researchers from the five continents) will be an opening step towards international collaboration and the dissemination of knowledge that is so important in this field of urban planning and territorial management

マルチスケール手法によるジオテキスタイル補強地盤の特性評価

広島大学(Hiroshima University)博士(工学)Doctor of Engineeringdoctora

A comparison of the performance of selected conceptual models of the rainfall-runoff process in semi-arid catchments near Grahamstown

A comparison of the performance of selected conceptual models of the rainfall-runoff process forms the central theme of this study and the comparison was conducted with three major objectives in mind. The first objective was to develop a conceptual model that could be used by practising hydrologists for the refinement and extension of historical streamflow records. The major requirements of the model were that it should be simple in structure and easy to operate and yet be flexible in terms of complexity of structure and input requirements as well as producing output at a level of accuracy that is competitive with that of the more complex models presently available. A comparison of the performance of the required model with that of other models formed an integral part of the development process. The second objective of the comparative study was to contribute to current knowledge of the criteria used in the selection of a suitable model for a particular application. There are, at present, no reliable guidelines to assist the hydrologist in selecting a suitable model from the wide range of models available and a comparative study would indicate the merits of various forms of model structure. The third objective is associated with the problems that arise when no streamflow data are available for model calibration. One approach is to calibrate the model in a nearby gauged catchment that the hydrologist regards as being 'hydrologically similar' and transferring the model parameter values to the ungauged catchment. Little is known about the feasibility of this parameter transfer process or about the choice of a model for such an application. The third objective was to test the feasibility of the parameter transfer process and to make use of the comparison of model performance to determine the model characteristics that are most suitable for the purpos

Modeling of Soil Erosion and Sediment Transport

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

The Ohio State University Version of the Stanford Streamflow Simulation Model

PROJECTS B-005-OHIO B-019-OHIOIn three parts: Part I -- Technical Aspects: A detailed analytical and descriptive presentation of the basic model with discussions on the input and output options, modifications made, test applications, performance evaluation, and developmental topics for future researchPart II: The Computer Program: Definition of program variables (386) and listing of the program statements (1881)Part III - User's Manual: A working understanding of the model so that the potential user can use it efficiently and effectively as a tool in hydrologic investigation2nd printing June 1974Part I: Preface -- Acknowledgments -- Introduction -- Hydrologic Concepts of the Watershed Model -- Input and Output Options -- Modification of the Stanford Watershed Model -- Application to Small Agricultural Watersheds -- Results and Discussion -- Summary, Conclusions, and Recommendations -- ReferencesPart II: Preface -- Acknowledgements -- Block Diagram of the Model -- Dictionary of the Program Variables -- Program ListingPart III: Preface -- Acknowledgments -- Introduction -- Uses and Limitations of the Model -- Basic Requirements -- Model Operation -- Appendix -- Reference

Geo-Environmental Approaches for the Analysis and Assessment of Groundwater Resources at Catchment-Scale

This book focuses on the tools and methods used for tackling the complexity of the different hydrological and hydrogeological set-ups, the hydrodynamic patterns, the site specifications, and the wide variability of internal and external factors and/or processes on the catchment-scale level that impose the need for combined integrated approaches of robust methods. This Special Issue aims to provide successful applications or new insights on the stand-alone or joint considerations of groundwater resources assessment and characterization methods and explore new state-of-the-art methodological concepts in light of a rapidly changing environment