WorldWideScience

Sample records for wepp water erosion

  1. Geospatial application of the Water Erosion Prediction Project (WEPP) model

    Science.gov (United States)

    At the hillslope profile and/or field scale, a simple Windows graphical user interface (GUI) is available to easily specify the slope, soil, and management inputs for application of the USDA Water Erosion Prediction Project (WEPP) model. Likewise, basic small watershed configurations of a few hillsl...

  2. Geospatial application of the Water Erosion Prediction Project (WEPP) model

    Science.gov (United States)

    D. C. Flanagan; J. R. Frankenberger; T. A. Cochrane; C. S. Renschler; W. J. Elliot

    2013-01-01

    At the hillslope profile and/or field scale, a simple Windows graphical user interface (GUI) is available to easily specify the slope, soil, and management inputs for application of the USDA Water Erosion Prediction Project (WEPP) model. Likewise, basic small watershed configurations of a few hillslopes and channels can be created and simulated with this GUI. However,...

  3. Implementation of channel-routing routines in the Water Erosion Prediction Project (WEPP) model

    Science.gov (United States)

    Li Wang; Joan Q. Wu; William J. Elliott; Shuhui Dun; Sergey Lapin; Fritz R. Fiedler; Dennis C. Flanagan

    2010-01-01

    The Water Erosion Prediction Project (WEPP) model is a process-based, continuous-simulation, watershed hydrology and erosion model. It is an important tool for water erosion simulation owing to its unique functionality in representing diverse landuse and management conditions. Its applicability is limited to relatively small watersheds since its current version does...

  4. Adapting the Water Erosion Prediction Project (WEPP) model for forest applications

    Science.gov (United States)

    Shuhui Dun; Joan Q. Wu; William J. Elliot; Peter R. Robichaud; Dennis C. Flanagan; James R. Frankenberger; Robert E. Brown; Arthur C. Xu

    2009-01-01

    There has been an increasing public concern over forest stream pollution by excessive sedimentation due to natural or human disturbances. Adequate erosion simulation tools are needed for sound management of forest resources. The Water Erosion Prediction Project (WEPP) watershed model has proved useful in forest applications where Hortonian flow is the major form of...

  5. Watershed-scale evaluation of the Water Erosion Prediction Project (WEPP) model in the Lake Tahoe basin

    Science.gov (United States)

    Erin S. Brooks; Mariana Dobre; William J. Elliot; Joan Q. Wu; Jan Boll

    2016-01-01

    Forest managers need methods to evaluate the impacts of management at the watershed scale. The Water Erosion Prediction Project (WEPP) has the ability to model disturbed forested hillslopes, but has difficulty addressing some of the critical processes that are important at a watershed scale, including baseflow and water yield. In order to apply WEPP to...

  6. Fuels planning: science synthesis and integration; environmental consequences fact sheet 12: Water Erosion Prediction Project (WEPP) Fuel Management (FuMe) tool

    Science.gov (United States)

    William Elliot; David Hall

    2005-01-01

    The Water Erosion Prediction Project (WEPP) Fuel Management (FuMe) tool was developed to estimate sediment generated by fuel management activities. WEPP FuMe estimates sediment generated for 12 fuel-related conditions from a single input. This fact sheet identifies the intended users and uses, required inputs, what the model does, and tells the user how to obtain the...

  7. Using WEPP technology to predict erosion and runoff following wildfire

    Science.gov (United States)

    William J. Elliot; Ina Sue Miller; Brandon D. Glaza

    2006-01-01

    Erosion following wildfire can be as much as 1000 times the erosion from an undisturbed forest. In August, 2005, the largest fire in the lower 48 states occurred in the Umatilla National Forest in Southeast Washington. Researchers from the Rocky Mountain Research Station assisted the forest in estimating soil erosion using three different applications of the WEPP model...

  8. [Anti-erosion effect of hedgerows in hillside croplands of Danjiangkou based on the evaluation with water erosion prediction project (WEPP) model].

    Science.gov (United States)

    Xiong, Qin-xue; Liu, Zhang-yong; Yao, Gui-zhi; Li, Ben-zhou

    2010-09-01

    Based on the data of field experiments on the hillside croplands of Danjiangkou, Hubei Province of China, the input files of crop characters, management measures, slope gradient and length, and soil properties for running WEPP model (Hillslope version) were established. Combining with the local weather data, a simulation study with the model was made on the runoff and soil loss of the croplands protected by four kinds of hedgerows (Amorpha fruticosa, Lonicera japonica, Hemerocallis fulva, and Poa sphondylodes) in Danjiangkou area. The resulted showed that WEPP model could accurately simulate the anti-erosion effect of hedgerows in hillside farmlands in the study area. Using this model not only reduced test number, but also saved time and effort, being able to provide scientific basis for the popularization and application of hedgerows. Among the four hedgerows, Amorpha fruticosa had the best anti-erosion effect. According to the simulation, the optimal planting density of A. fruticosa hedgerows in the farmlands was 1 m x 15 m at slope gradient 5 degrees, 1 m x 10 m at slope gradient 15 degrees, and 1 m x 3 m at slope gradient 25 degrees.

  9. Application of the Water Erosion Prediction Project (WEPP) Model to simulate streamflow in a PNW forest watershed

    Science.gov (United States)

    A. Srivastava; M. Dobre; E. Bruner; W. J. Elliot; I. S. Miller; J. Q. Wu

    2011-01-01

    Assessment of water yields from watersheds into streams and rivers is critical to managing water supply and supporting aquatic life. Surface runoff typically contributes the most to peak discharge of a hydrograph while subsurface flow dominates the falling limb of hydrograph and baseflow contributes to streamflow from shallow unconfined aquifers primarily during the...

  10. Incorporating groundwater flow into the WEPP model

    Science.gov (United States)

    William Elliot; Erin Brooks; Tim Link; Sue Miller

    2010-01-01

    The water erosion prediction project (WEPP) model is a physically-based hydrology and erosion model. In recent years, the hydrology prediction within the model has been improved for forest watershed modeling by incorporating shallow lateral flow into watershed runoff prediction. This has greatly improved WEPP's hydrologic performance on small watersheds with...

  11. Modeling erosion under future climates with the WEPP model

    Science.gov (United States)

    Timothy Bayley; William Elliot; Mark A. Nearing; D. Phillp Guertin; Thomas Johnson; David Goodrich; Dennis Flanagan

    2010-01-01

    The Water Erosion Prediction Project Climate Assessment Tool (WEPPCAT) was developed to be an easy-to-use, web-based erosion model that allows users to adjust climate inputs for user-specified climate scenarios. WEPPCAT allows the user to modify monthly mean climate parameters, including maximum and minimum temperatures, number of wet days, precipitation, and...

  12. Usability and Functional Enhancements to an Online Interface for Predicting Post Fire Erosion (WEPP-PEP)

    Science.gov (United States)

    Lew, Roger; Dobre, Mariana; Elliot, William; Robichaud, Pete; Brooks, Erin; Frankenberger, Jim

    2017-04-01

    There is an increased interest in the United States to use soil burn severity maps in watershed-scale hydrologic models to estimate post-fire sediment erosion from burned areas. This information is needed by stakeholders in order to concentrate their pre- or post-fire management efforts in ecologically sensitive areas to decrease the probability of post-fire sediment delivery. But these tools traditionally have been time consuming and difficult to use by managers because input datasets must be obtained and correctly processed for valid results. The Water Erosion Prediction Project (WEPP) has previously been developed as an online and easy-to-use interface to help land managers with running simulations without any knowledge of computer programming or hydrologic modeling. The interface automates the acquisition of DEM, climate, soils, and landcover data, and also automates channel and hillslope delineation for the users. The backend is built with Mapserver, GDAL, PHP, C++, Python while the front end uses OpenLayers, and, of course, JavaScript. The existing WEPP online interface was enhanced to provide better usability to stakeholders in United States (Forest Service, BLM, USDA) as well as to provide enhanced functionality for managing both pre-fire and post-fire treatments. Previously, only site administrators could add burn severity maps. The interface now allows users to create accounts to upload and share FlamMap prediction maps, differenced Normalized Burned Ratio (dNBR), or Burned Area Reflectance Classification (BARC) maps. All maps are loaded into a sortable catalog so users can quickly find their area of interest. Once loaded, the interface has been modified to support running comparisons between baseline condition with "no burn" and with a burn severity classification map. The interface has also been enhanced to allow users to conduct single storm analyses to examine, for example, how much soil loss would result after a 100-year storm. An OpenLayers map

  13. WEPP Model applications for evaluations of best management practices

    Science.gov (United States)

    D. C. Flanagan; W. J. Elliott; J. R. Frankenberger; C. Huang

    2010-01-01

    The Water Erosion Prediction Project (WEPP) model is a process-based erosion prediction technology for application to small watersheds and hillslope profiles, under agricultural, forested, rangeland, and other land management conditions. Developed by the United States Department of Agriculture (USDA) over the past 25 years, WEPP simulates many of the physical processes...

  14. WEPP modeling in the Great Lakes Basin

    Science.gov (United States)

    The USDA-ARS Water Erosion Prediction Project (WEPP) model is a state-of-the-art physical process-based computer simulation model for estimating runoff, soil erosion, and sediment losses from a range of land management systems, including cropland, rangeland, and forests. The National Soil Erosion Re...

  15. First application of the WEPP model to predict runoff and erosion risk in fire-affected volcanic areas in Europe

    Science.gov (United States)

    Neris, Jonay; Robichaud, Peter R.; Elliot, William J.; Doerr, Stefan H.; Notario del Pino, Jesús S.; Lado, Marcos

    2017-04-01

    An estimated that 15% of the world's population lives in volcanic areas. Recent catastrophic erosion events following wildfires in volcanic terrain have highlighted the geomorphological instability of this soil type under disturbed conditions and steep slopes. Predicting the hydrological and erosional response of this soils in the post-fire period is the first step to design and develop adequate actions to minimize risks in the post-fire period. In this work we apply, for the first time, the Water Erosion Prediction Project model for predicting erosion and runoff events in fire-affected volcanic soils in Europe. Two areas affected by wildfires in 2015 were selected in Tenerife (Spain) representative of different fire behaviour (downhill surface fire with long residence time vs uphill crown fire with short residence time), severity (moderate soil burn severity vs light soil burn severity) and climatic conditions (average annual precipitation of 750 and 210 mm respectively). The actual erosion processes were monitored in the field using silt fences. Rainfall and rill simulations were conducted to determine hydrologic, interrill and rill erosion parameters. The soils were sampled and key properties used as model input, evaluated. During the first 18 months after the fire 7 storms produced runoff and erosion in the selected areas. Sediment delivery reached 5.4 and 2.5 Mg ha-1 respectively in the first rainfall event monitored after the fire, figures comparable to those reported for fire-affected areas of the western USA with similar climatic conditions but lower than those showed by wetter environments. The validation of the WEPP model using field data showed reasonable estimates of hillslope sediment delivery in the post-fire period and, therefore, it is suggested that this model can support land managers in volcanic areas in Europe in predicting post-fire hydrological and erosional risks and designing suitable mitigation treatments.

  16. Commonalities in WEPP and WEPS and efforts towards a single erosion process model

    NARCIS (Netherlands)

    Visser, S.M.; Flanagan, D.C.

    2004-01-01

    Since the late 1980's, the Agricultural Research Service (ARS) of the United States Department of Agriculture (USDA) has been developing process-based erosion models to predict water erosion and wind erosion. During much of that time, the development efforts of the Water Erosion Prediction Project

  17. Evaluación del modelo WEPP para predecir la erosión hídrica en pastizales semiáridos del noreste de la Patagonia Evaluation of the WEPP model to predict soil erosion in northeastern Patagonian rangelands

    Directory of Open Access Journals (Sweden)

    Marcelo P Chartier

    2010-07-01

    Full Text Available Los modelos matemáticos son herramientas útiles para la predicción de las pérdidas de suelo por erosión hídrica. El desarrollo reciente del modelo WEPP y su utilización para evaluar los riesgos de erosión en pastizales naturales ha significado un avance interesante en el campo de la erosión y la conservación de suelos de estos ecosistemas. En este trabajo examinamos la eficiencia del modelo WEPP para predecir los procesos hidrológicos y de erosión del suelo en los pastizales naturales semiáridos del noreste de la provincia de Chubut. Se identificaron tres comunidades de plantas ubicadas a lo largo de un gradiente de degradación del suelo: estepa herbácea con arbustos aislados (EH, estepa herbáceo-arbustiva (EHA y estepa arbustiva degradada (EA. En cada una de estas comunidades se aplicó una lluvia simulada (100 mm h-1 durante 30 min sobre parcelas de 1 m² (0,6 x 1,67 m y se colectó el escurrimiento y los sedimentos totales. A partir de los datos de la condición superficial de cada parcela se estimó el escurrimiento y la producción de sedimentos mediante el modelo WEPP. En este trabajo se observó una baja eficiencia del modelo WEPP para predecir el escurrimiento (Eficiencia, E = 0,14 y la erosión del suelo (E = -0,93. La predicción del escurrimiento y pérdida de suelo del modelo WEPP mostró mayor sensibilidad a cambios en los parámetros de lluvia y pendiente del terreno y una sensibilidad moderada a cambios en la cobertura, textura, erodabilidad del suelo y conductividad hidráulica efectiva. El escurrimiento y la producción de sedimentos estimados por WEPP fueron significativamente diferentes en las distintas comunidades de plantas (p Mathematical models are useful tools to predict soil loss by water erosion. The recent development of the WEPP model and its use in assessing the risks of erosion in rangelands has led to significant advances in the field of erosion and soil conservation of these ecosystems. In this

  18. Anthropogenic changes and environmental degradation in pre-Hispanic and post-Colonial periods: soil erosion modelled with WEPP during Late Holocene in Teotihuacán Valley (central Mexico)

    Science.gov (United States)

    Lourdes González-Arqueros, M.; Mendoza Cantú, Manuel E.

    2015-04-01

    Land use changes and support practices are a worldwide significant issue in soil erosion and subsequently, land degradation. Anthropogenic changes, along different periods of the history in the last 2000 years in the Valley of Teotihuacan (central Mexico), highlight that soil erosion varies depending on how the management and the intensity of soil use is handled, considering the soils as a main resource. As a part of a broader effort to reconstruct the erosion dynamics in the Teotihuacán Valley through geoarchaeological approaches, this study apply a process-based watershed hydrology and upland erosion model, Water Erosion Prediction Project (WEPP). This research aims to contribute with insights through modelling and to recreate soil erosion and sedimentation dynamics in several historical periods with different environmental and anthropogenic scenarios. The Geo-spatial interface for WEPP (GeoWEPP) was used to characterize location of detachment, depositions and erosion predicted on the profile through time, based on current and hypothetical reconstructed conditions in the watershed. Climate, topography, soil and land use were used as inputs for the WEPP model to estimate runoff fluxes, soil loss rates, and sediment delivery ratio (SDR) for three historical scenarios: current period, reconstructed Teotihuacán period (AD 1-650), and reconstructed Aztec period (AD 1325-1520). Over a simulated and stablished timeframe for those social periods, the runoff, soil loss rate and SDR were estimated to be greater during the Aztec period. We assume that in general the climate conditions for this period were wetter, compared with present, in agreement with several authors that proposed climate reconstructions for the center of Mexico. It is also highlighted that support practices were more effective in this period. The next period with higher values is the current one, and fewer rates are estimated for the Teotihuacán period. This comparison release new arguments in the

  19. Comparison of SWAT and GeoWEPP model in predicting the impact of stone bunds on runoff and erosion processes in the Northern Ethiopian Highlands

    Science.gov (United States)

    Demelash, Nigus; Flagler, Jared; Renschler, Chris; Strohmeier, Stefan; Holzmann, Hubert; Feras, Ziadat; Addis, Hailu; Zucca, Claudio; Bayu, Wondimu; Klik, Andreas

    2017-04-01

    Soil degradation is a major issue in the Ethiopian highlands which are most suitable for agriculture and, therefore, support a major part of human population and livestock. Heavy rainstorms during the rainy season in summer create soil erosion and runoff processes which affect soil fertility and food security. In the last years programs for soil conservation and afforestation were initiated by the Ethiopian government to reduce erosion risk, retain water in the landscape and improve crop yields. The study was done in two adjacent watersheds in the Northwestern highlands of Ethiopia. One of the watersheds is developed by soil and water conservation structures (stone bunds) in 2011 and the other one is without soil and water conservation structures. Spatial distribution of soil textures and other soil properties were determined in the field and in the laboratory and a soil map was derived. A land use map was evaluated based on satellite images and ground truth data. A Digital Elevation Model of the watershed was developed based on conventional terrestrial surveying using a total station. At the outlet of the watersheds weirs with cameras were installed to measure surface runoff. During each event runoff samples were collected and sediment concentration was analyzed. The objective of this study is 1) to assess the impact of stone bunds on runoff and erosion processes by using simulation models, and 2) to compare the performance of two soil erosion models in predicting the measurements. The selected erosion models were the Soil and Water Assessment Tool (SWAT) and the Geospatial Interface to the Water Erosion Prediction Project (GeoWEPP). The simulation models were calibrated/verified for the 2011-2013 periods and validated with 2014-2015 data. Results of this comparison will be presented.

  20. Erosion processes and prediction with WEPP technology in forests in the Northwestern U.S.

    Science.gov (United States)

    W. J. Elliot

    2013-01-01

    In the northwestern U.S., the greatest amounts of forest erosion usually follow infrequent wildfires. Sediment from these fires is gradually routed through the stream system. The forest road network is usually the second greatest source of sediment, generating sediment annually. Erosion rates associated with timber harvest, biomass removal, and prescribed fire are...

  1. Modeling sediment transport from an off-road vehicle trail stream crossing using WEPP model

    Science.gov (United States)

    Renee' D. Ayala; Puneet Srivastava; Christian J. Brodbeck; Emily A. Carter; Timothy P. McDonald

    2005-01-01

    There is a limited information available pertaining to the adverse effects of Off-Road-Vehicle (ORV) use and trail impacts. As a result, this study was initiated in 2003 to (a) quantify water quality impacts of an ORV trail stream crossing through monitoring of total suspended solids, and (b) conduct WEPP (Water Erosion Prediction Project) simulations to determine long...

  2. Modeling runoff and sediment yield from a terraced watershed using WEPP

    Science.gov (United States)

    Mary Carla McCullough; Dean E. Eisenhauer; Michael G. Dosskey

    2008-01-01

    The watershed version of WEPP (Water Erosion Prediction Project) was used to estimate 50-year runoff and sediment yields for a 291 ha watershed in eastern Nebraska that is 90% terraced and which has no historical gage data. The watershed has a complex matrix of elements, including terraced and non-terraced subwatersheds, multiple combinations of soils and land...

  3. Identification of effective best management practices in sediment yield diminution using GeoWEPP: the Kasilian watershed case study.

    Science.gov (United States)

    Reza Meghdadi, Amin

    2013-12-01

    Identifying areas that are susceptible to soil erosion is crucial for water resource planning and management efforts. Furthermore, modeling has proven helpful in recognizing and monitoring high-risk areas at the watershed scale. The Water Erosion Prediction Project (WEPP) geospatial interface (GeoWEPP) software integrates GIS with the WEPP to analyze the spatial variation in soil loss, and it has been used as a modeling tool to determine the areas that are most prone to soil erosion and to evaluate best management practices for the Kasilian watershed in Iran. As much as 62.4% of the agronomic land in the Kasilian watershed is affected by a high magnitude of erosion (>5 t/ha). On the basis of this study, by using soybeans, high fertilization levels, and the drill-no-tillage system, reductions of erosion by almost 32.68-34.02% are perceivable in three critical subwatersheds that are located in the cultivated lands. Also, it is projected that reductions in the production of sediment in the range of about 36.7-47.1% are achievable by structural management within two critical, upland subwatersheds. So, by utilizing the best management strategies, sediment yield can be lowered and the conservation of soil and water is feasible at the watershed scale. These results objectively indicate that GeoWEPP can be efficaciously used for evaluating effective management practices for developing watershed conservation.

  4. Validation of a probabilistic post-fire erosion model

    Science.gov (United States)

    Pete Robichaud; William J. Elliot; Sarah A. Lewis; Mary Ellen Miller

    2016-01-01

    Post-fire increases of runoff and erosion often occur and land managers need tools to be able to project the increased risk. The Erosion Risk Management Tool (ERMiT) uses the Water Erosion Prediction Project (WEPP) model as the underlying processor. ERMiT predicts the probability of a given amount of hillslope sediment delivery from a single rainfall or...

  5. Soil Loss in Samaru Zaria Nigeria: A Comparison of Wepp and ...

    African Journals Online (AJOL)

    Soil erosion data generated while estimating soil loss in Samaru, Zaria using the EUROSEM model were used as input parameters for the prediction of soil loss in the same catchment area using the WEPP erosion model. A comparative analysis of both models for soil loss prediction showed that WEPP performed better for ...

  6. Developing relations between soil erodibilty factors in two different soil erosion prediction models (USLE/RUSLE and wWEPP) and fludization bed technique for mechanical soil cohesion

    Science.gov (United States)

    Soil erosion models are valuable analysis tools that scientists and engineers use to examine observed data sets and predict the effects of possible future soil loss. In the area of water erosion, a variety of modeling technologies are available, ranging from solely qualitative models, to merely quan...

  7. Land use and climate change impacts on runoff and soil erosion at the hillslope scale in the Brazilian Cerrad

    Science.gov (United States)

    Changes in land use and climate can influence runoff and soil erosion, threatening soil and water conservation in the Cerrado biome in Brazil. The adoption of a process-based model was necessary due to the lack of long-term observed data. Our goals were to calibrate the WEPP (Water Erosion Predictio...

  8. BASINS and WEPP Climate Assessment Tools (CAT): Case ...

    Science.gov (United States)

    This draft report supports application of two recently developed water modeling tools, the BASINS and WEPP climate assessment tools. The report presents a series of short case studies designed to illustrate the capabilities of these tools for conducting scenario based assessments of the potential future effects of climate change on water resources. This report presents a series of short, illustrative case studies using the BASINS and WEPP climate assessment tools.

  9. Soil erosion by water - model concepts and application

    Science.gov (United States)

    Schmidt, Juergen

    2010-05-01

    approaches will be discussed taking account of the models WEPP, EUROSEM, IISEM and EROSION 3D. In order to provide a better representation of spatially heterogeneous catchments in terms of landuse, soil, slope, and rainfall most of recently developed models operate on a grid-cell basis or other kinds of sub-units, each having uniform characteristics. These so-called "Distributed Models" accepts inputs from raster based geographic information system (GIS). The cell-based structure of the models also allows to generate drainage paths by which water and sediment can be routed from the top to the bottom of the respective watershed. One of the open problems in soil erosion modelling refers to the spontaneous generation of erosion rills without the need for pre-existing morphological contours. A promising approach to handle this problem was realized first in the RILLGROW model, which uses a cellular automaton system in order to generate realistic rill patterns. With respect to the above mentioned models selected applications will be presented and discussed regarding their usability for soil and water conservation purposes.

  10. Mechanics of interrill erosion with wind-driven rain

    NARCIS (Netherlands)

    Erpul, G.; Gabriels, D.; Norton, L.D.; Flanagan, D.C.; Huang, C.; Visser, S.M.

    2013-01-01

    The vector physics of wind-driven rain (WDR) differs from that of wind-free rain, and the interrill soil detachment equations in the Water Erosion Prediction Project (WEPP) model were not originally developed to deal with this phenomenon. This article provides an evaluation of the performance of the

  11. Mechanics of Interrill Erosion with Wind-Driven Rain (WDR)

    Science.gov (United States)

    This article provides an evaluation analysis for the performance of the interrill component of the Water Erosion Prediction Project (WEPP) model for Wind-Driven Rain (WDR) events. The interrill delivery rates (Di) were collected in the wind tunnel rainfall simulator facility of the International Cen...

  12. Mechanics of interrill erosion with wind-driven rain

    Science.gov (United States)

    The vector physics of wind-driven rain (WDR) differs from that of wind-free rain, and the interrill soil detachment equations in the Water Erosion Prediction Project (WEPP) model were not originally developed to deal with this phenomenon. This article provides an evaluation of the performance of the...

  13. The Application of a WEPP Technology to a Complex Watershed Analysis

    Science.gov (United States)

    Elliot, William; Miller, Ina Sue; Dobre, Mariana

    2017-04-01

    Forest restoration activities are essential in many forest stands, where previous management and fire suppression has resulted in stands with high density, diseased trees and excessive fuel loads. Trying to balance the watershed impacts of restoration activities such as thinning, selective harvesting, and prescribed fire against the significant impact of wildfire is challenging. The process is further aggravated by the necessity of a road network if management activities include timber removal. We propose to present an approach to a watershed analysis for a 3400-ha of fuel reduction project within an 18,0000-ha sensitive watershed in the Nez Perce National Forest in Northern Idaho, USA. The FlamMap fire spread model was first used to predict the distribution of potential fire severity on the landscape for the current fuel load, and for a landscape that had been treated by thinning and/or prescribed fire. FlamMap predicts the flame length by 30-m pixel as a function of fuel load and water content, wind speed, and slope steepness and aspect. The flame length distribution was then classified so that the distribution of burn severity (unburned, low, moderate and high severity) was similar to the distributions observed on recent wildfires in the Forest. The flame length classes determined for the current fuel loads were also used for the treated condition flame lengths, where predominantly unburned or low severity fire severities were predicted. The burn severity maps were uploaded to a web site that was developed to provide soil and management files reflecting burn severity and soil texture, formatted for the Geospatial interface to the Water Erosion Prediction Project (GeoWEPP). The study area was divided into 40 sub watersheds under 2.5 km2 each for GeoWEPP analysis. GeoWEPP was run for an undisturbed forest; for the burn severity following wildfire for the current and treated fuel loads; for prescribed fire, either broadcast or jack pot burn; and for thinning either

  14. Evaluación del modelo WEPP para predecir la erosión hídrica en pastizales semiáridos del noreste de la Patagonia Evaluation of the WEPP model to predict soil erosion in northeastern Patagonian rangelands

    OpenAIRE

    Marcelo P Chartier; César M Rostagno

    2010-01-01

    Los modelos matemáticos son herramientas útiles para la predicción de las pérdidas de suelo por erosión hídrica. El desarrollo reciente del modelo WEPP y su utilización para evaluar los riesgos de erosión en pastizales naturales ha significado un avance interesante en el campo de la erosión y la conservación de suelos de estos ecosistemas. En este trabajo examinamos la eficiencia del modelo WEPP para predecir los procesos hidrológicos y de erosión del suelo en los pastizales naturales semiári...

  15. BASINs and WEPP Climate Assessment Tools (CAT): Case Study Guide to Potential Applications (Final Report)

    Science.gov (United States)

    EPA announced the release of the final report, BASINs and WEPP Climate Assessment Tools (CAT): Case Study Guide to Potential Applications. This report supports application of two recently developed water modeling tools, the Better Assessment Science Integrating point & ...

  16. Land use and climate change impacts on runoff and soil erosion at the hillslope scale in the Brazilian Cerrado.

    Science.gov (United States)

    Anache, Jamil A A; Flanagan, Dennis C; Srivastava, Anurag; Wendland, Edson C

    2018-05-01

    Land use and climate change can influence runoff and soil erosion, threatening soil and water conservation in the Cerrado biome in Brazil. The adoption of a process-based model was necessary due to the lack of long-term observed data. Our goals were to calibrate the WEPP (Water Erosion Prediction Project) model for different land uses under subtropical conditions in the Cerrado biome; predict runoff and soil erosion for these different land uses; and simulate runoff and soil erosion considering climate change. We performed the model calibration using a 5-year dataset (2012-2016) of observed runoff and soil loss in four different land uses (wooded Cerrado, tilled fallow without plant cover, pasture, and sugarcane) in experimental plots. Selected soil and management parameters were optimized for each land use during the WEPP model calibration with the existing field data. The simulations were conducted using the calibrated WEPP model components with a 100-year climate dataset created with CLIGEN (weather generator) based on regional climate statistics. We obtained downscaled General Circulation Model (GCM) projections, and runoff and soil loss were predicted with WEPP using future climate scenarios for 2030, 2060, and 2090 considering different Representative Concentration Pathways (RCPs). The WEPP model had an acceptable performance for the subtropical conditions. Land use can influence runoff and soil loss rates in a significant way. Potential climate changes, which indicate the increase of rainfall intensities and depths, may increase the variability and rates of runoff and soil erosion. However, projected climate changes did not significantly affect the runoff and soil erosion for the four analyzed land uses at our location. Finally, the runoff behavior was distinct for each land use, but for soil loss we found similarities between pasture and wooded Cerrado, suggesting that the soil may attain a sustainable level when the land management follows conservation

  17. Large Scale Predictions of Potential Post-fire Erosion

    Science.gov (United States)

    Miller, M. E.; MacDonald, L. H.

    2005-12-01

    High-severity wildfires are of increasing concern because of their potential for initiating flash floods and surface erosion, degrading water quality, and reducing reservoir capacity. In many areas fire suppression has increased fuel accumulations and hence the potential for high-severity wildfires. Land management agencies are undertaking programs to reduce fuel loadings and the associated risk of high-severity wildfires, but the areas needing treatment greatly exceed the available funding. It is therefore necessary to determine which areas should have a higher priority for such treatments. Similarly, when wildfires do occur there is an immediate need to determine which areas should have the highest priority for post-fire rehabilitation treatments. One criterion for allocating treatments is the potential risk of post-fire erosion, but to be effective this assessment needs to be carried out at a broad scale. This paper presents a procedure and initial results for predicting spatially-explicit, post-fire erosion risks at the hillslope scale for forest and shrub lands across the western U.S. Our approach utilizes existing physical models and datasets in a GIS framework. The model for predicting erosion is GeoWEPP, the Geographical interface for the Water Erosion Prediction Project (WEPP). The primary inputs for GeoWEPP include climate, topography, soils, and land cover/land use. Daily climate inputs were generated with Cligen, which is a stochastic weather generator distributed with WEPP. A 30-m digital elevation model, STATSGO-derived soils data, and vegetation cover were obtained from the U.S. Forest Service's LANDFIRE project. Since recent research has shown that percent ground cover is a dominant control on post-fire erosion rates, we generated a spatially-explicit map of post-fire ground cover by first using historic weather data to determine the 1000-hr fuel moisture values when fuel conditions were at 98-100% ERC (Energy Released Component). These fuel

  18. The development of U. S. soil erosion prediction and modeling

    Directory of Open Access Journals (Sweden)

    John M. Laflen

    2013-09-01

    Full Text Available Soil erosion prediction technology began over 70 years ago when Austin Zingg published a relationship between soil erosion (by water and land slope and length, followed shortly by a relationship by Dwight Smith that expanded this equation to include conservation practices. But, it was nearly 20 years before this work's expansion resulted in the Universal Soil Loss Equation (USLE, perhaps the foremost achievement in soil erosion prediction in the last century. The USLE has increased in application and complexity, and its usefulness and limitations have led to the development of additional technologies and new science in soil erosion research and prediction. Main among these new technologies is the Water Erosion Prediction Project (WEPP model, which has helped to overcome many of the shortcomings of the USLE, and increased the scale over which erosion by water can be predicted. Areas of application of erosion prediction include almost all land types: urban, rural, cropland, forests, rangeland, and construction sites. Specialty applications of WEPP include prediction of radioactive material movement with soils at a superfund cleanup site, and near real-time daily estimation of soil erosion for the entire state of Iowa.

  19. Validating and Improving Interrill Erosion Equations

    Science.gov (United States)

    Zhang, Feng-Bao; Wang, Zhan-Li; Yang, Ming-Yi

    2014-01-01

    Existing interrill erosion equations based on mini-plot experiments have largely ignored the effects of slope length and plot size on interrill erosion rate. This paper describes a series of simulated rainfall experiments which were conducted according to a randomized factorial design for five slope lengths (0.4, 0.8, 1.2, 1.6, and 2 m) at a width of 0.4 m, five slope gradients (17%, 27%, 36%, 47%, and 58%), and five rainfall intensities (48, 62.4, 102, 149, and 170 mm h−1) to perform a systematic validation of existing interrill erosion equations based on mini-plots. The results indicated that the existing interrill erosion equations do not adequately describe the relationships between interrill erosion rate and its influencing factors with increasing slope length and rainfall intensity. Univariate analysis of variance showed that runoff rate, rainfall intensity, slope gradient, and slope length had significant effects on interrill erosion rate and that their interactions were significant at p = 0.01. An improved interrill erosion equation was constructed by analyzing the relationships of sediment concentration with rainfall intensity, slope length, and slope gradient. In the improved interrill erosion equation, the runoff rate and slope factor are the same as in the interrill erosion equation in the Water Erosion Prediction Project (WEPP), with the weight of rainfall intensity adjusted by an exponent of 0.22 and a slope length term added with an exponent of −0.25. Using experimental data from WEPP cropland soil field interrill erodibility experiments, it has been shown that the improved interrill erosion equation describes the relationship between interrill erosion rate and runoff rate, rainfall intensity, slope gradient, and slope length reasonably well and better than existing interrill erosion equations. PMID:24516624

  20. Water erosion of dystrophic Red Latosols (Oxisols

    Directory of Open Access Journals (Sweden)

    Joaquim Ernesto Bernardes Ayer

    2015-06-01

    Full Text Available In their natural state, Latosols (Oxisols present great stability and resistance to erosion, being the most abundant and used soils for farming and cattle raising activities in southern Minas Gerais State, Brazil. However, along the last one hundred years, they have been submitted to intensive cultivation and managements which favor water erosion. This study aimed to estimate the water erosion rates of dystrophic Red Latosols from the Revised Universal Soil Loss Equation, compared with the soil loss tolerance limits, and assess the impact on water erosion of the managements more common in the region, by alternative conservation management simulation. Soil loss tolerance limits ranged from 8.94 Mg ha-1 year-1 to 9.99 Mg ha-1 year-1, with the study area presenting a susceptibility of soil loss of 23.86 Mg year-1, with an average rate of 8.40 Mg ha-1 year-1, corresponding to 34.80 % of the area with values above the soil loss tolerance limit. The biggest annual losses occur in areas with use and management of eucalyptus grown downhill (30.67 Mg ha-1 year-1 and pasture under continuous occupancy (11.10 Mg ha-1 year-1. However, when the average loss per type of use is considered, the areas more susceptible to water erosion are those with potato and eucalyptus crops, grown downhill, and those in bare soil. Nevertheless, in the simulated conservation management scenario, the average losses would be drastically reduced (8.40 Mg ha-1 year-1 to 2.84 Mg ha-1 year-1 and only 4.00 % of the area with soil loss would remain above the tolerance limits.

  1. Water erosion as a cause for agricultural soil loss: modeling of dynamic processes using high-resolution ground based LiDAR measurements

    Science.gov (United States)

    Oz, Imri; Filin, Sagi; Assouline, Shmuel; Shtain, Zachi; Furman, Alexander

    2016-04-01

    Soil erosion by rainfall and water flow is a frequent natural geomorphic process shaping the earth's surface at various scales. Conventional agrotechnical methods enhance soil erosion at the field scale and are at the origin of the reduction of the upper soil layer depth. This reduction is expressed in two aspects: decrease of soil depth, mainly due to erosion, and the diminution of soil quality, mainly due to the loss of fine material, nutrients and organic matter. Rain events, not even the most extremes, cause detachment and transport of fertile soil rich in organic matter and nutrients away from the fields, filling and plugging drainage channels, blocking infrastructure and contaminating water sources. Empirical, semi-empirical and mechanistic models are available to estimate soil erosion by water flow and sediment transport (e.g. WEPP, KINEROSS, EUROSEM). Calibration of these models requires data measured at high spatial and temporal resolutions. Development of high-resolution measurement tools (for both spatial and temporal aspects) should improve the calibration of functions related to particles detachment and transport from the soil surface. In addition, despite the great impact of different tillage systems on the soil erosion process, the vast majority of the models ignore this fundamental factor. The objective of this study is to apply high-resolution ground-based LiDAR measurements to different tillage schemes and scales to improve the ability of models to accurately describe the process of soil erosion induced by rainfall and overland flow. Ground-based laser scans provide high resolution accurate and subtle geomorphic changes, as well as larger-scale deformations. As such, it allows frequent monitoring, so that even the effect of a single storm can be measured, thus improving the calibration of the erosion models. Preliminary results for scans made in the field show the potential and limitations of ground-based LiDAR, and at this point qualitatively can

  2. The WEPP Model Application in a Small Watershed in the Loess Plateau.

    Directory of Open Access Journals (Sweden)

    Fengpeng Han

    Full Text Available In the Loess Plateau, soil erosion has not only caused serious ecological and environmental problems but has also impacted downstream areas. Therefore, a model is needed to guide the comprehensive control of soil erosion. In this study, we introduced the WEPP model to simulate soil erosion both at the slope and watershed scales. Our analyses showed that: the simulated values at the slope scale were very close to the measured. However, both the runoff and soil erosion simulated values at the watershed scale were higher than the measured. At the slope scale, under different coverage, the simulated erosion was slightly higher than the measured. When the coverage is 40%, the simulated results of both runoff and erosion are the best. At the watershed scale, the actual annual runoff of the Liudaogou watershed is 83 m(3; sediment content is 0.097 t/m(3, annual erosion sediment 8.057 t and erosion intensity 0.288 t ha(-1 yr(-1. Both the simulated values of soil erosion and runoff are higher than the measured, especially the runoff. But the simulated erosion trend is relatively accurate after the farmland is returned to grassland. We concluded that the WEPP model can be used to establish a reasonable vegetation restoration model and guide the vegetation restoration of the Loess Plateau.

  3. How well does the Post-fire Erosion Risk Management Tool (ERMiT) really work?

    Science.gov (United States)

    Robichaud, Peter; Elliot, William; Lewis, Sarah; Miller, Mary Ellen

    2016-04-01

    The decision of where, when, and how to apply the most effective postfire erosion mitigation treatments requires land managers to assess the risk of damaging runoff and erosion events occurring after a fire. The Erosion Risk Management Tool (ERMiT) was developed to assist post fire assessment teams identify high erosion risk areas and effectiveness of various mitigation treatments to reduce that risk. ERMiT is a web-based application that uses the Water Erosion Prediction Project (WEPP) technology to estimate erosion, in probabilistic terms, on burned and recovering forest, range, and chaparral lands with and without the application of mitigation treatments. User inputs are processed by ERMiT to combine rain event variability with spatial and temporal variabilities of hillslope burn severity and soil properties which are then used as WEPP inputs. Since 2007, the model has been used in making hundreds of land management decisions in the US and elsewhere. We use eight published field study sites in the Western US to compare ERMiT predictions to observed hillslope erosion rates. Most sites experience only a few rainfall events that produced runoff and sediment except for a California site with a Mediterranean climate. When hillslope erosion occurred, significant correlations occurred between the observed hillslope erosion and those predicted by ERMiT. Significant correlation occurred for most mitigation treatments as well as the five recovery years. These model validation results suggest reasonable estimates of probabilistic post-fire hillslope sediment delivery when compared to observation.

  4. Satellite remote sensing for water erosion assessment: A review

    NARCIS (Netherlands)

    Vrieling, A.

    2006-01-01

    Water erosion creates negative impacts on agricultural production, infrastructure, and water quality across the world. Regional-scale water erosion assessment is important, but limited by data availability and quality. Satellite remote sensing can contribute through providing spatial data to such

  5. BASINS and WEPP Climate Assessment Tools (CAT): Case Study Guide to Potential Applications (External Review Draft)

    Science.gov (United States)

    This draft report supports application of two recently developed water modeling tools, the BASINS and WEPP climate assessment tools. The report presents a series of short case studies designed to illustrate the capabilities of these tools for conducting scenario based assessments...

  6. Can control of soil erosion mitigate water pollution by sediments?

    Science.gov (United States)

    Rickson, R J

    2014-01-15

    The detrimental impact of sediment and associated pollutants on water quality is widely acknowledged, with many watercourses in the UK failing to meet the standard of 'good ecological status'. Catchment sediment budgets show that hill slope erosion processes can be significant sources of waterborne sediment, with rates of erosion likely to increase given predicted future weather patterns. However, linking on-site erosion rates with off-site impacts is complicated because of the limited data on soil erosion rates in the UK and the dynamic nature of the source-pathway-receptor continuum over space and time. Even so, soil erosion control measures are designed to reduce sediment production (source) and mobilisation/transport (pathway) on hill slopes, with consequent mitigation of pollution incidents in watercourses (receptors). The purpose of this paper is to review the scientific evidence of the effectiveness of erosion control measures used in the UK to reduce sediment loads of hill slope origin in watercourses. Although over 73 soil erosion mitigation measures have been identified from the literature, empirical data on erosion control effectiveness are limited. Baseline comparisons for the 18 measures where data do exist reveal erosion control effectiveness is highly variable over time and between study locations. Given the limitations of the evidence base in terms of geographical coverage and duration of monitoring, performance of the different measures cannot be extrapolated to other areas. This uncertainty in effectiveness has implications for implementing erosion/sediment risk reduction policies, where quantified targets are stipulated, as is the case in the EU Freshwater Fish and draft Soil Framework Directives. Also, demonstrating technical effectiveness of erosion control measures alone will not encourage uptake by land managers: quantifying the costs and benefits of adopting erosion mitigation is equally important, but these are uncertain and difficult to

  7. Water Impingement Erosion of Deep-Rolled Ti64

    Directory of Open Access Journals (Sweden)

    Dina Ma

    2015-08-01

    Full Text Available In this work, the Liquid Impingement Erosion (LIE performances of deep-rolling (DR treated and non-treated Ti64 were investigated. Various erosion stages, from the incubation to the terminal erosion stages, could be observed. A full factorial design of experiments was used to study the effect of DR process parameters (Feed Rate, Spindle Velocity, Number of Passes, Pressure on the residual stress distribution, microhardness and surface roughness of the treated Ti64 specimens. The DR-treated Ti64 specimens exhibited improved surface microhardness, surface roughness, and large magnitude of compressive residual stresses, which were attributed to the amount of cold work induced by the DR process. Although DR improved the mechanical properties of the Ti64, the results showed that the treatment has little or no effect on the LIE performance of Ti64 but different damage modes were observed in these two cases. Evolution of the erosion stages was described based on water-hammer pressure, stress waves, radial wall jetting, and hydraulic penetration modes. The initial erosion stages were mainly influenced by water-hammer pressure and stress waves, whereas the intermediate erosion stages were influenced by the combination of the four modes together. The final erosion stages contain the four modes, however the erosion was greatly driven by the radial jetting and hydraulic penetration modes, where more material was removed. The failure mechanism of the final stages of the LIE test of both DR-treated and non-treated Ti64 was characterized as fatigue fracture. However, a brittle fracture behavior was observed in the initial and intermediate erosion stages of the DR-treated Ti64, whereas a ductile fracture behavior was observed in the non-treated Ti64. This was concluded from the micrographs of the LIE damage through different erosion stages.

  8. Water Erosion in Different Slope Lengths on Bare Soil

    Directory of Open Access Journals (Sweden)

    Bárbara Bagio

    Full Text Available ABSTRACT Water erosion degrades the soil and contaminates the environment, and one influential factor on erosion is slope length. The aim of this study was to quantify losses of soil (SL and water (WL in a Humic Cambisol in a field experiment under natural rainfall conditions from July 4, 2014 to June 18, 2015 in individual events of 41 erosive rains in the Southern Plateau of Santa Catarina and to estimate soil losses through the USLE and RUSLE models. The treatments consisted of slope lengths of 11, 22, 33, and 44 m, with an average degree of slope of 8 %, on bare and uncropped soil that had been cultivated with corn prior to the study. At the end of the corn cycle, the stalk residue was removed from the surface, leaving the roots of the crop in the soil. Soil loss by water erosion is related linearly and positively to the increase in slope length in the span between 11 and 44 m. Soil losses were related to water losses and the Erosivity Index (EI30, while water losses were related to rain depth. Soil losses estimated by the USLE and RUSLE model showed lower values than the values observed experimentally in the field, especially the values estimated by the USLE. The values of factor L calculated for slope length of 11, 22, 33, and 44 m for the two versions (USLE and RUSLE of the soil loss prediction model showed satisfactory results in relation to the values of soil losses observed.

  9. Water droplet erosion of stainless steel steam turbine blades

    Science.gov (United States)

    Kirols, H. S.; Kevorkov, D.; Uihlein, A.; Medraj, M.

    2017-08-01

    Steam turbine blades are highly subjected to water droplet erosion (WDE) caused by high energy impingement of liquid water droplets. However, most of the published research on this wear phenomenon is performed on laboratory test rigs, instead of addressing WDE of actual steam turbine blades. In this work, the progression of erosion on the surface of ex-service low pressure steam turbine blades was investigated using scanning electron microscopy. The erosion appearance and mechanisms are compared with laboratory test rig results that are carried out using a rotating disk rig according to ASTM G73 standard. Initial and advanced erosion stages could be observed on the steam turbine blades. Similar to the WDE rig coupons, initial pits and cracks were preceded by blade surface roughening through the formation of asperities and depressions. In addition, it was also observed that the twist angle of the turbine blade around its diagonal, is an important parameter that influences its WDE. Twist angle has an effect on: impact angle, erosion appearance, impact speed, and the affected area. Furthermore, according to the current experimental results, multi-ray rig erosion test results are considered the closest simulation to the actual ex-service blade in terms of damage appearance.

  10. Water erosion and climate change in a small alpine catchment

    Science.gov (United States)

    Berteni, Francesca; Grossi, Giovanna

    2017-04-01

    WATER EROSION AND CLIMATE CHANGE IN A SMALL ALPINE CATCHMENT Francesca Berteni, Giovanna Grossi A change in the mean and variability of some variables of the climate system is expected to affect the sediment yield of mountainous areas in several ways: for example through soil temperature and precipitation peak intensity change, permafrost thawing, snow- and ice-melt time shifting. Water erosion, sediment transport and yield and the effects of climate change on these physical phenomena are the focus of this work. The study area is a small mountainous basin, the Guerna creek watershed, located in the Central Southern Alps. The sensitivity of sediment yield estimates to a change of condition of the climate system may be investigated through the application of different models, each characterized by its own features and limits. In this preliminary analysis two different empirical mathematical models are considered: RUSLE (Revised Universal Soil Loss Equation; Renard et al., 1991) and EPM (Erosion Potential Method; Gavrilovic, 1988). These models are implemented in a Geographical Information System (GIS) supporting the management of the territorial database used to estimate relevant geomorphological parameters and to create different thematic maps. From one side the geographical and geomorphological information is required (land use, slope and hydrogeological instability, resistance to erosion, lithological characterization and granulometric composition). On the other side the knowledge of the weather-climate parameters (precipitation and temperature data) is fundamental as well to evaluate the intensity and variability of the erosive processes and estimate the sediment yield at the basin outlet. Therefore different climate change scenarios were considered in order to tentatively assess the impact on the water erosion and sediment yield at the small basin scale. Keywords: water erosion, sediment yield, climate change, empirical mathematical models, EPM, RUSLE, GIS

  11. Multifractal Model of Soil Water Erosion

    Science.gov (United States)

    Oleshko, Klaudia

    2017-04-01

    Breaking of solid surface symmetry during the interaction between the rainfall of high erosivity index and internally unstable volcanic soil/vegetation systems, results in roughness increasing as well as fertile horizon loosing. In these areas, the sustainability of management practices depends on the ability to select and implement the precise indicators of soil erodibility and vegetation capacity to protect the system against the extreme damaging precipitation events. Notwithstanding, the complex, non-linear and scaling nature of the phenomena involved in the interaction among the soil, vegetation and precipitation is still not taken into account by the numerous commonly used empirical, mathematical and computer simulation models: for instance, by the universal soil loss equation (USLE). The soil erodibility factor (K-factor) is still measuring by a set of empirical, dimensionless parameters and indexes, without taking into account the scaling (frequently multifractal) origin of a broad range of heterogeneous, anisotropic and dynamical phenomena involved in hydric erosion. Their mapping is not representative of this complex system spatial variability. In our research, we propose to use the toolbox of fractals and multifractals techniques in vista of its ability to measure the scale invariance and type/degree of soil, vegetation and precipitation symmetry breaking. The hydraulic units are chosen as the precise measure of soil/vegetation stability. These units are measured and modeled for soils with contrasting architecture, based on their porosity/permeability (Poroperm) as well as retention capacity relations. The simple Catalog of the most common Poroperm relations is proposed and the main power law relations among the elements of studied system are established and compared for some representative agricultural and natural Biogeosystems of Mexico. All resulted are related with the Mandelbrot' Baby Theorem in order to construct the universal Phase Diagram which

  12. THE WATER FROM NATURE AND THE EROSION PROCESS

    Directory of Open Access Journals (Sweden)

    G. PANDI

    2015-03-01

    Full Text Available The water from nature and the erosion process. Studying earth's surface erosion process is necessary for practical reasons. The theoretical approach requires knowledge of the alluvial system’s structure and operation as the cascade sequence of fluvial system’s mass and energy. Geosystem research methodology requires that the water energy and the role of adjacent surface must be expressed. The expression of water power can be grouped according to the shape of movement and action in the basin. A particular, important case is the energy variation in a basin-slope. An important role in energy expressions is considering the existence in nature of biphasic fluid - water as dispersion phase and solid particles as dispersed phase. The role of the adjacent surface is taken into account by using the erosion resistance indicator, which is calculated using the indicator of geological resistance and the indicator of plant protection. The evolution of natural systems, therefore of river basins too, leads to energy diminishing, thus affecting their dynamic balance. This can be expressed using the concept of entropy. Although erosion processes are usual natural phenomena for the evolution of river basins, they induce significant risks in certain circumstances. Depending on the circulated water energies, water basins can be ranked in terms of potential risks.

  13. Dynamics of soil organic carbon and microbial biomass carbon in relation to water erosion and tillage erosion.

    Science.gov (United States)

    Xiaojun, Nie; Jianhui, Zhang; Zhengan, Su

    2013-01-01

    Dynamics of soil organic carbon (SOC) are associated with soil erosion, yet there is a shortage of research concerning the relationship between soil erosion, SOC, and especially microbial biomass carbon (MBC). In this paper, we selected two typical slope landscapes including gentle and steep slopes from the Sichuan Basin, China, and used the (137)Cs technique to determine the effects of water erosion and tillage erosion on the dynamics of SOC and MBC. Soil samples for the determination of (137)Cs, SOC, MBC and soil particle-size fractions were collected on two types of contrasting hillslopes. (137)Cs data revealed that soil loss occurred at upper slope positions of the two landscapes and soil accumulation at the lower slope positions. Soil erosion rates as well as distribution patterns of the erosion is the major process of soil redistribution in the gentle slope landscape, while tillage erosion acts as the dominant process of soil redistribution in the steep slope landscape. In gentle slope landscapes, both SOC and MBC contents increased downslope and these distribution patterns were closely linked to soil redistribution rates. In steep slope landscapes, only SOC contents increased downslope, dependent on soil redistribution. It is noticeable that MBC/SOC ratios were significantly lower in gentle slope landscapes than in steep slope landscapes, implying that water erosion has a negative effect on the microbial biomass compared with tillage erosion. It is suggested that MBC dynamics are closely associated with soil redistribution by water erosion but independent of that by tillage erosion, while SOC dynamics are influenced by soil redistribution by both water erosion and tillage erosion.

  14. Ornamental landscaping for water erosion control at the federal ...

    African Journals Online (AJOL)

    Water erosion causes serious problems in the environment. The condition is accelerated by the reduction of vegetation resulting from indiscriminate logging of timber and other deforestation activities, which may include the slash and burn method of land preparation and continuous cropping on a particular land over time.

  15. Ecological site-based assessments of wind and water erosion: informing accelerated soil erosion management in rangelands

    Science.gov (United States)

    Webb, Nicholas P.; Herrick, Jeffrey E.; Duniway, Michael C.

    2014-01-01

    Accelerated soil erosion occurs when anthropogenic processes modify soil, vegetation or climatic conditions causing erosion rates at a location to exceed their natural variability. Identifying where and when accelerated erosion occurs is a critical first step toward its effective management. Here we explore how erosion assessments structured in the context of ecological sites (a land classification based on soils, landscape setting and ecological potential) and their vegetation states (plant assemblages that may change due to management) can inform systems for reducing accelerated soil erosion in rangelands. We evaluated aeolian horizontal sediment flux and fluvial sediment erosion rates for five ecological sites in southern New Mexico, USA, using monitoring data and rangeland-specific wind and water erosion models. Across the ecological sites, plots in shrub-encroached and shrub-dominated vegetation states were consistently susceptible to aeolian sediment flux and fluvial sediment erosion. Both processes were found to be highly variable for grassland and grass-succulent states across the ecological sites at the plot scale (0.25 Ha). We identify vegetation thresholds that define cover levels below which rapid (exponential) increases in aeolian sediment flux and fluvial sediment erosion occur across the ecological sites and vegetation states. Aeolian sediment flux and fluvial erosion in the study area can be effectively controlled when bare ground cover is 100 cm in length is less than ~35%. Land use and management activities that alter cover levels such that they cross thresholds, and/or drive vegetation state changes, may increase the susceptibility of areas to erosion. Land use impacts that are constrained within the range of natural variability should not result in accelerated soil erosion. Evaluating land condition against the erosion thresholds identified here will enable identification of areas susceptible to accelerated soil erosion and the development of

  16. Ecological site‐based assessments of wind and water erosion: informing accelerated soil erosion management in rangelands.

    Science.gov (United States)

    Webb, Nicholas P; Herrick, Jeffrey E; Duniway, Michael C

    Accelerated soil erosion occurs when anthropogenic processes modify soil, vegetation, or climatic conditions causing erosion rates at a location to exceed their natural variability. Identifying where and when accelerated erosion occurs is a critical first step toward its effective management. Here we explored how erosion assessments structured in the context of ecological sites (a land classification based on soils, landscape setting, and ecological potential) and their vegetation states (plant assemblages that may change due to management) can inform systems for reducing accelerated soil erosion in rangelands. We evaluated aeolian horizontal sediment flux and fluvial sediment erosion rates for five ecological sites in southern New Mexico, USA, using monitoring data and rangeland-specific wind and water erosion models. Across the ecological sites, plots in shrub-encroached and shrub-dominated vegetation states were consistently susceptible to aeolian sediment flux and fluvial sediment erosion. Both processes were found to be highly variable for grassland and grass–succulent states across the ecological sites at the plot scale (0.25 ha). We identified vegetation thresholds that define cover levels below which rapid (exponential) increases in aeolian sediment flux and fluvial sediment erosion occur across the ecological sites and vegetation states. Aeolian sediment flux and fluvial erosion in the study area could be effectively controlled when bare ground cover was 100 cm in length was less than ∼35%. Land use and management activities that alter cover levels such that they cross thresholds, and/or drive vegetation state changes, may increase the susceptibility of areas to erosion. Land use impacts that are constrained within the range of natural variability should not result in accelerated soil erosion. Evaluating land condition against the erosion thresholds identified here will enable identification of areas susceptible to accelerated soil erosion and the

  17. 7 CFR 610.12 - Equations for predicting soil loss due to water erosion.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Equations for predicting soil loss due to water... ASSISTANCE Soil Erosion Prediction Equations § 610.12 Equations for predicting soil loss due to water erosion. (a) The equation for predicting soil loss due to erosion for both the USLE and the RUSLE is A = R × K...

  18. Simulation of Surface Erosion on a Logging Road in the Jackson Demonstration State Forest

    Science.gov (United States)

    Teresa Ish; David Tomberlin

    2007-01-01

    In constructing management models for the control of sediment delivery to streams, we have used a simulation model of road surface erosion known as the Watershed Erosion Prediction Project (WEPP) model, developed by the USDA Forest Service. This model predicts discharge, erosion, and sediment delivery at the road segment level, based on a stochastic climate simulator...

  19. Quantifying accelerated soil erosion through ecological site-based assessments of wind and water erosion

    Science.gov (United States)

    This work explores how organising soil erosion assessments using established groupings of similar soils (ecological sites) can inform systems for managing accelerated soil erosion. We evaluated aeolian sediment transport and fluvial erosion rates for five ecological sites in southern New Mexico, USA...

  20. Soil Erosion by Water in Perennial Plantations of the Ilok Region

    OpenAIRE

    Kustura, Antonija; Kisić, Ivica; Bašić, Ferdo; Jurišić, Aleksandra

    2008-01-01

    Soil erosion by water is a natural process, in which soil particles get detached from soil mass, transported and deposited at a distance. Erosion depends on a number of natural factors, such as terrain slope, amount and intensity of precipitation, soil (structure, mechanical composition, permeability, infiltration, etc.), wind, crop rotation, and plant cover. Soil erosion by water is one of the most dangerous soil damaging processes. In the hilly part of the studied region, erosion causes gre...

  1. Mapping regional soil water erosion risk in the Brittany-Loire basin for water management agency

    Science.gov (United States)

    Degan, Francesca; Cerdan, Olivier; Salvador-Blanes, Sébastien; Gautier, Jean-Noël

    2014-05-01

    Soil water erosion is one of the main degradation processes that affect soils through the removal of soil particles from the surface. The impacts for environment and agricultural areas are diverse, such as water pollution, crop yield depression, organic matter loss and reduction in water storage capacity. There is therefore a strong need to produce maps at the regional scale to help environmental policy makers and soil and water management bodies to mitigate the effect of water and soil pollution. Our approach aims to model and map soil erosion risk at regional scale (155 000 km²) and high spatial resolution (50 m) in the Brittany - Loire basin. The factors responsible for soil erosion are different according to the spatial and time scales considered. The regional scale entails challenges about homogeneous data sets availability, spatial resolution of results, various erosion processes and agricultural practices. We chose to improve the MESALES model (Le Bissonnais et al., 2002) to map soil erosion risk, because it was developed specifically for water erosion in agricultural fields in temperate areas. The MESALES model consists in a decision tree which gives for each combination of factors the corresponding class of soil erosion risk. Four factors that determine soil erosion risk are considered: soils, land cover, climate and topography. The first main improvement of the model consists in using newly available datasets that are more accurate than the initial ones. The datasets used cover all the study area homogeneously. Soil dataset has a 1/1 000 000 scale and attributes such as texture, soil type, rock fragment and parent material are used. The climate dataset has a spatial resolution of 8 km and a temporal resolution of mm/day for 12 years. Elevation dataset has a spatial resolution of 50 m. Three different land cover datasets are used where the finest spatial resolution is 50 m over three years. Using these datasets, four erosion factors are characterized and

  2. The water erosion processes in the retreat erosive of cliff on soft rocks in the province of Cadiz (Spain); Los procesos de erosion hidrica en el retroceso erosivo de acantilados sobre rocas blandas en la provincia de Cadiz

    Energy Technology Data Exchange (ETDEWEB)

    Rendon Aragon, J. J.; Gracia Prieto, F. J.; Rio Rodriguez, L. del

    2009-07-01

    The littoral cliffs on soft materials of the Atlantic Cadiz coast show an important activity of the fresh water erosion processes, sometimes even more significant than the marine erosion processes. The connection of the lower cliffs with sandy beaches favours aeolian sand invasion, which fills previous rills and reduces the water erosion intensity by increasing infiltration. Cliff retreat and rill erosion measurement by using erosion sticks has shown very variables values, most of them higher than the estimated error of the employed methods. This indicates the existence of other factors influencing the distribution of water erosion processes along these cliffs, which have to be studied through different techniques. (Author) 5 refs.

  3. Relationships between slope erosion processes and aggregate stability of Ultisols from subtropical China during rainstorms

    Science.gov (United States)

    Liu, Gang; Xiao, Hai; Liu, Puling

    2017-04-01

    Soil aggregates, being a key soil structural unit, influence several soil physical properties such as water infiltration, runoff and erosion. The relationship between soil aggregate stability and interrill and rill erodibility is unclear but critical to process-based erosion prediction models. One obvious reason is that it is hard to distinguish between interrill and rill-eroded sediment during the erosion process. This study was designed to partition interrill and rill erosion rates and relates them to the aggregate stability of Ultisols in subtropical China. Six kinds of rare earth element (REE) were applied as tracers mixed with two cultivated soils derived from the Quaternary red clay soil and the shale soil at six slope positions. Soil aggregate stability was determined by the Le Bissonnais (LB)-method. Simulated rainfall with three intensities (60, 90 and 120 mm/h) were applied to a soil plot (2.25 m long, 0.5 m wide, 0.2 m deep) at three slope gradients (10°, 20° and 30°) with duration of 30 min after runoff initiation. The results indicated that interrill and rill erosion increased with increasing rainfall intensity and slope gradient for both types of soil. Rill and interrill erosion rates of the shale soil were much higher than those of the Quaternary red clay soil. Rill erosion contribution enhanced with increasing rainfall intensity and slope gradient for both soils. Percentage of the downslope area erosion to total erosion was the largest, followed by the mid-slope area and then upslope area. Equations using an aggregate stability index As to replace the erodibility factor of interrill and rill erosion in the Water Erosion Prediction Project (WEPP) model were constructed after analyzing the relationships between estimated and measured rill and interrill erosion data. It was shown that these equations based on the stability index, As, have the potential to improve methods for assessing interrill and rill erosion erodibility synchronously for the

  4. The variability of runoff and soil erosion in the Brazilian Cerrado biome due to the potential land use and climate changes

    Science.gov (United States)

    Alexandre Ayach Anache, Jamil; Wendland, Edson; Malacarne Pinheiro Rosalem, Lívia; Srivastava, Anurag; Flanagan, Dennis

    2017-04-01

    Changes in land use and climate can influence runoff and soil loss, threatening soil and water conservation in the Cerrado biome in Brazil. Due to the lack of long term observed data for runoff and soil erosion in Brazil, the adoption of a process-based model was necessary, representing the variability of both variables in a continuous simulation approach. Thus, we aimed to calibrate WEPP (Water Erosion Prediction Project) model for different land uses (undisturbed Cerrado, fallow, pasture, and sugarcane) under subtropical conditions inside the Cerrado biome; predict runoff and soil erosion for these different land uses; and simulate runoff and soil erosion considering climate change scenarios. We performed the model calibration using a 4-year dataset of observed runoff and soil loss in four different land uses (undisturbed Cerrado, fallow, pasture, and sugarcane). The WEPP model components (climate, topography, soil, and management) were calibrated according to field data. However, soil and management were optimized according to each land use using a parameter estimation tool. The observations were conducted between 2012 and 2015 in experimental plots (5 m width, 20 m length, 9% slope gradient, 3 replicates per treatment). The simulations were done using the calibrated WEPP model components, but changing the 4-year observed climate file by a 100-year dataset created with CLIGEN (weather generator) based on regional climate statistics. Afterwards, using MarkSim DSSAT Weather File Generator, runoff and soil loss were simulated using future climate scenarios for 2030, 2060, and 2090. To analyze the data, we used non-parametric statistics as data do not follow normal distribution. The results show that WEPP model had an acceptable performance for the considered conditions. In addition, both land use and climate can influence on runoff and soil loss rates. Potential climate changes which consider the increase of rainfall intensities and depths in the studied region may

  5. Beryllium-7 measurements of wind erosion on sloping fields in the wind-water erosion crisscross region on the Chinese Loess Plateau.

    Science.gov (United States)

    Zhang, Jiaqiong; Yang, Mingyi; Deng, Xinxin; Liu, Zhang; Zhang, Fengbao; Zhou, Weiying

    2018-02-15

    Soil erosion is complex in the wind-water erosion crisscross region of the Chinese Loess Plateau, as interleaving of wind and water erosion occurs on both temporal and spatial scales. It is difficult to distinguish wind erosion from the total erosion in previous studies due to the untraceable of aeolian particles and the limitation of feasible methods and techniques. This study used beryllium-7 measurements to study wind erosion in the wind-water erosion crisscross region on the Chinese Loess Plateau arms to delineate wind erosion distribution, to analyze its implication to erosive winds and surface microrelief, and to determine correlations between erosion rates and slope gradients. Results obtained using beryllium-7 measurements based on observation plots were verified with saltating particle collection method, and were also verified on a field scale. Results indicated that the effective resultant erosion wind was from northward, which was proved by the eight-directional distributed saltating particles. The microrelief of the ground surface contributed to the formation of high or low erosion centers. Wind erosion rates increased with a linear (R 2 ≥0.95) or exponential (R 2 ≥0.83) fitting increase in the slope gradients as reported in previous studies. Compared to wind erosion on field scale, both the plots and fields exhibited similar distribution patterns in wind erosion isolines. We also determined that the wind erosion rate for two fields estimated, based on equations developed from plot scale was acceptable. This study validates the feasibility of beryllium-7 measurements for soil-wind erosion field experiments and the potential to expand this approach to real field conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Cavitation erosion of copper and aluminium in water at elevated-temperature

    CSIR Research Space (South Africa)

    Auret, JG

    1993-12-01

    Full Text Available Cavitation erosion tests were carried out in tap water on aluminium and copper samples in a rotating disk cavitations test apparatus, to study the effect of water temperature on cavitation dynamics and cavitation erosion. A shift in the position...

  7. Farmers' perceptions of erosion by wind and water in northern Burkina Faso

    NARCIS (Netherlands)

    Visser, S.M.; Leenders, J.K.; Leeuwis, M.

    2003-01-01

    Wind and water erosion are widespread phenomena throughout the Sahel, especially in the early rainy season, when high-intensity rainstorms are often preceded by severe windstorms. This paper describes the results of a survey on the farmers' perceptions of wind and water erosion processes and control

  8. Nutrient and Organic Carbon Losses, Enrichment Rate, and Cost of Water Erosion

    OpenAIRE

    Ildegardis Bertol; Rodrigo Vieira Luciano; Camilo Bertol; Bárbara Bagio

    2017-01-01

    ABSTRACT Soil erosion from water causes loss of nutrients and organic carbon, enriches the environment outside the erosion site, and results in costs. The no-tillage system generates increased nutrient and C content in the topsoil and, although it controls erosion, it can produce a more enriched runoff than in the conventional tillage system. This study was conducted in a Humic Cambisol in natural rainfall from 1997 to 2012 to quantify the contents and total losses of nutrients and organic C ...

  9. Characteristics of water erosion and conservation practice in arid regions of Central Asia: Xinjiang Province, China as an example

    OpenAIRE

    Zhang, Wentai; Zhou, Jianqin; Feng, Guanglong; Weindorf, David C.; Hu, Guiqing; Sheng, Jiandong

    2015-01-01

    Located in the inland arid area of Central Asia and northwest China, Xinjiang has recently received heightened concerns over soil water erosion, which is highly related with the sustainable utilization of barren soil and limited water resources. Data from the national soil erosion survey of China (1985–2011) and Xinjiang statistical yearbook (2000–2010) was used to analyze the trend, intensity, and serious soil water erosion regions. Results showed that the water erosion area in Xinjiang was ...

  10. Modeling post-fire water erosion mitigation strategies

    Directory of Open Access Journals (Sweden)

    M. C. Rulli

    2013-06-01

    Full Text Available Severe wildfires are often followed by significant increase in runoff and erosion, due to vegetation damage and changes in physical and chemical soil properties. Peak flows and sediment yields can increase up to two orders of magnitude, becoming dangerous for human lives and the ecosystem, especially in the wildland–urban interface. Watershed post-fire rehabilitation measures are usually used to mitigate the effects of fire on runoff and erosion, by protecting soil from splash and shear stress detachment and enhancing its infiltration capacity. Modeling post-fire erosion and erosion mitigation strategies can be useful in selecting the effectiveness of a rehabilitation method. In this paper a distributed model based on the Revised Universal Soil Loss Equation (RUSLE, properly parameterized for a Mediterranean basin located in Sardinia, is used to determine soil losses for six different scenarios describing both natural and post-fire basin condition, the last also accounting for the single and combined effect of different erosion mitigation measures. Fire effect on vegetation and soil properties have been mimed by changing soil drainage capacity and organic matter content, and RUSLE factors related to soil cover and protection measures. Model results, validated using measured data on erosion rates from the literature and in situ field campaigns, show the effect of the analyzed rehabilitation treatments in reducing the amount of soil losses with the peculiar characteristics of the spatial distribution of such changes. In particular, the mulching treatment substantially decreases erosion both in its mean value (−75% and in the spatially distribution of the erosion levels over the burned area . On the contrary, the breaking up of the hydrophobic layer decreases post-fire mean soil losses of about the 14%, although it strongly influences the spatial distribution of the erosion levels.

  11. Cavitation pitting and erosion of Al 6061-T6 in mineral oil and water

    Science.gov (United States)

    Rao, B. C. S.; Buckley, D. H.

    1983-01-01

    The authors are currently carrying out a study of the cavitation erosion of different bearing metals and alloys in mineral oils were studied. The variations of weight loss, the pit diameter and depth due to cavitation erosion on Al 6061-T6 in mineral oil and water are presented.

  12. Land management, erosion problems and soil and water conservation in Fincha'a watershed, western Ethiopia

    NARCIS (Netherlands)

    Bezuayehu, T.; Sterk, G.

    2010-01-01

    The knowledge of soil erosion processes, attitude towards rational use of resources and institutional support affect the capability of farmers to implement soil and water conservation (SWC) measures. This research was conducted to determine soil erosion problems and the factors that affect the

  13. Risk assessment of pesticide transport with water erosion: A conceptual model

    Science.gov (United States)

    Yang, Xiaomei; Van Der Zee, Sjoerd E. A. T. M.; Gai, Lingtong; Wesseling, Jan G.; Ritsema, Coen J.; Geissen, Violette

    2017-04-01

    Pesticides are widely used in agriculture, horticulture, and forestry, and pesticide pollution has become an important issue worldwide. Entraining in runoff and being attached to eroded soil particles, posing a risk to water and soil quality and human health. In order to assess the risk of pesticide during water erosion processes, a simple integrative model of pesticide transport by runoff and erosion was developed. Taking soil hydrological and pesticide behaviour into account, such as water infiltration, erosion, runoff, and pesticide transport and degradation in soil, the conceptual framework was based on the known assumptions such as the convection-dispersion equation and lognormal distributions of soil properties associated with transport, sorption, degradation, and erosion. A sensitivity analysis was conducted and the results indicated that the total amount of pesticide related to soil eroded by water washing increased with slope gradient, rainfall intensity, and water field capacity of the soil. The mass of transported pesticide decreased as the micro-topography of the soil surface became obviously and the time from pesticide sprayed to erosion occurring associated with pesticide degradation negatively influenced the total amount of transported pesticide. The mechanisms involved in pesticide transport, such as runoff, infiltration, soil erosion, and pesticide transport and decay in the topsoil, thus can be well accounted for pesticide risk assessment especially in the region with intensive pesticide use and soil water erosion events.

  14. Behavior of farmers in regard to erosion by water as reflected by their farming practices.

    Science.gov (United States)

    Auerswald, Karl; Fischer, Franziska K; Kistler, Michael; Treisch, Melanie; Maier, Harald; Brandhuber, Robert

    2018-02-01

    The interplay between natural site conditions and farming raises erosion by water above geological background levels. We examined the hypothesis that farmers take erosion into account in their farming decisions and switch to farming practices with lower erosion risk the higher the site-specific hazard becomes. Erosion since the last tillage was observed from aerial orthorectified photographs for 8100 fields belonging to 1879 farmers distributed across Bavaria (South Germany) and it was modeled by the Universal Soil Loss Equation using highly detailed input data (e.g., digital terrain model with 5×5m 2 resolution, rain data with 1×1km 2 and 5min resolution, crop and cropping method from annual field-specific data from incentive schemes). Observed and predicted soil loss correlated closely, demonstrating the accuracy of this method. The close correlation also indicted that the farmers could easily observe the degree of recent erosion on their fields, even without modelling. Farmers clearly did not consider erosion in their decisions. When natural risk increased, e.g. due to steeper slopes, they neither grew crops with lower erosion potential, nor reduced field size, nor used contouring. In addition, they did not compensate for the cultivation of crops with higher erosion potential by using conservation techniques like mulch tillage or contouring, or by reducing field size. Only subsidized measures, like mulch tillage or organic farming, were applied but only at the absolute minimum that was necessary to obtain subsidies. However, this did not achieve the reduction in erosion that would be possible if these measures had been fully applied. We conclude that subsidies may be an appropriate method of reducing erosion but the present weak supervision, which assumes that farmers themselves will take erosion into account and that subsidies are only needed to compensate for any disadvantages caused by erosion-reducing measures, is clearly not justified. Copyright © 2017

  15. Wildfires effect on water erosion response of different mediterranean forest soils

    Science.gov (United States)

    Andreu, V.; Forteza, J.; Rubio, J. L.

    2009-04-01

    Some of the morphological characteristics of the Mediterranean landscapes are partly due to the incidence of forest fires. Different intensities and different environmental conditions give place to different forms of water erosion responses and ways of ecosystems recovery. In this work, the effect of fire on the response to erosion processes of different type of soils under different environmental conditions has been studied. Immediately after a wildfire that affected 9478 ha of the Sierra Calderona (Valencia, SPAIN), six monitoring stations to study the evolution of water erosion processes were placed. The stations cover different fire intensities and environmental situations. Topographical, pedological and vegetation characteristics of each station were studied. The effect of erosive rain events on runoff and sediment production, during a five years period was evaluated. Erosive patterns in the studied zones were similar, but with slight variations depending on the rainfall distribution on the whole area and the different topographical conditions. The data show that, in general, for all the stations the most important soil losses were produced in the first four months after the fire, and then these losses decrease progressively with time. Although the data show high heterogeneity, it has been observed that together with the intrinsic characteristics of fire and rain events, soil profile properties can also be determinant factors in the incidence of water erosion and in the recovery of the vegetation cover under similar environmental conditions. Keywords: Wildfires, Mediterranean soils, water erosion, soil loss, runoff generation, rain aggressiveness.

  16. Potential impacts of climate change on rainfall erosivity and water availability in China in the next 100 years

    Science.gov (United States)

    Ge Sun; Steven G. McNulty; Jennifer Moore; Corey Bunch; Jian Ni

    2002-01-01

    Soil erosion and water shortages threaten China’s social and economic development in the 21st century. This paper examines how projected climate change could affect soil erosion and water availability across China. We used both historical climate data (1961-1980) and the UKMO Hadley3 climate scenario (1960-2099) to drive regional hydrology and soil erosivity models....

  17. Rainfall simulation experiments: Influence of water temperature, water quality and plot design on soil erosion and runoff

    Science.gov (United States)

    Iserloh, Thomas; Pegoraro, Dominique; Schlösser, Angelika; Thesing, Hannah; Seeger, Manuel; Ries, Johannes B.

    2015-04-01

    Field rainfall simulators are designed to study soil erosion processes and provide urgently needed data for various geomorphological, hydrological and pedological issues. Due to the different conditions and technologies applied, there are several methodological aspects under review of the scientific community, particularly concerning design, procedures and conditions of measurement for infiltration, runoff and soil erosion. This study aims at contributing fundamental data for understanding rainfall simulations in depth by studying the effect of the following parameters on the measurement results: 1. Plot design - round or rectangular plot: Can we identify differences in amount of runoff and erosion? 2. Water quality: What is the influence of the water's salt load on interrill erosion and infiltration as measured by rainfall experiments? 3. Water temperature: How much are the results conditioned by the temperature of water, which is subject to changes due to environmental conditions during the experiments? Preliminary results show a moderate increase of soil erosion with the water's salt load while runoff stays almost on the same level. With increasing water temperature, runoff increases continuously. At very high temperatures, soil erosion is clearly increased. A first comparison between round and rectangular plot indicates the rectangular plot to be the most suitable plot shape, but ambiguous results make further research necessary. The analysis of these three factors concerning their influence on runoff and erosion shows that clear methodological standards are necessary in order to make rainfall simulation experiments comparable.

  18. Main issues for preserving Mediterranean soil resources from water erosion under global change

    Science.gov (United States)

    Raclot, Damien; Le Bissonnais, Yves; Annabi, Mohamed; Sabir, Mohamed; Smetanova, Anna

    2017-04-01

    Soil resources are important for the socio-economic development of the Mediterranean area, and their durability is sometimes threatened because of intense erosion processes that result in severe degradation in the field (on-site effects) and downstream degradation (off-site effects). Based on the literature and results obtained during several research projects, this paper aims to present the main lessons and challenges dealing with Mediterranean soil resources under global change. After a review of the main drivers of Mediterranean soil erosion and the main impacts of water erosion processes, the paper highlights that the nature and intensity of active erosion processes are as diverse as the mosaic of the Mediterranean landscape. It then discusses the expected evolution of Mediterranean soil resources under global change and illustrates the prevalent influences of land use (partly depending on climatic constraints) on the evolution of erosion risk and soil vulnerability. Finally it details some main challenges for the future of Mediterranean soil resources dealing with a better knowledge of factors and processes involved in soil erosion; a better evaluation of soil vulnerability through a combined quantitative and qualitative soil erosion approach; and the need for a site-specific conservation strategy for Mediterranean soil resources. KEYWORDS : Mediterranean, soil resources, global change, erosion, preservation.

  19. Use of rare earth oxides and iron oxides as soil erosion tracers in water erosion experiments at hillslope scale

    Science.gov (United States)

    Guzmán, G.; Cañasveras, J. C.; Barrón, V.; Boulal, H.; Gómez, H.; Conde, E.; Fernández, M.; Gómez, J. A.

    2010-05-01

    The characteristics of the ideal soil erosion have been defined by several authors, for example by Zhang et al. (2001). Despite intensive research on erosion tracers in the last decades there is not a single tracer fulfilling all these characteristics. That is why research on different soil erosion tracers remains as an active field. Two desirable characteristics in erosion tracers are that they should be relatively inexpensive (to purchase and analyze) and that they should be determined with high accuracy in soil or sediment. The availability of multiple tracers is another of the key requirements. In this communication we present our preliminary results on the use of two different sets of erosion tracers. One set are iron oxides with different magnetic and optical properties (Fe3O4, α-Fe2O3 and FeOOH) analyzed by NIRS and magnetic susceptibility measurements. The other set consists of five rare earth oxides (La2O3, Pr6O11, Nd2O3, Sm2O3 and Gd2O3) analyzed using inductively coupled plasma mass spectrometry (ICP-MS). These two groups were studied under controlled and natural conditions, through several water erosion experiments, in field plots with different soil management, crops and scale. In one experiment these tracers were used to determine the source of sediment within sprinkle irrigated fields planted with cotton on shoulders. For this purpose, rainfall simulations were performed under controlled conditions at two scales, one with a portable rainfall simulator at small scale (0.81m2) and with the sprinkler irrigation system in the whole cotton field (2450 m2). Furrows were tagged with both groups of tracers, keeping shoulders untagged (where cotton was planted). Soil samples before and after the rainfall simulations were collected as well as sediment samples. In another experiment four olive orchard plots (330 m2) with different soil managements (cover crop and conventional tillage) were also tagged with the two groups of tracers. Soil samples were taken at

  20. Development of a GIS interface for WEPP Model application to Great Lakes forested watersheds

    Science.gov (United States)

    J. R. Frankenberger; S. Dun; D. C. Flanagan; J. Q. Wu; W. J. Elliot

    2011-01-01

    This presentation will highlight efforts on development of a new online WEPP GIS interface, targeted toward application in forested regions bordering the Great Lakes. The key components and algorithms of the online GIS system will be outlined. The general procedures used to provide input to the WEPP model and to display model output will be demonstrated.

  1. Effects of Soil Management Practices on Water Erosion under Natural Rainfall Conditions on a Humic Dystrudept

    Directory of Open Access Journals (Sweden)

    Vinicius Ferreira Chaves de Souza

    Full Text Available ABSTRACT Water erosion is the main cause of soil degradation and is influenced by rainfall, soil, topography, land use, soil cover and management, and conservation practices. The objective of this study was to quantify water erosion in a Humic Dystrudept in two experiments. In experiment I, treatments consisted of different rates of fertilizer applied to the soil surface under no-tillage conditions. In experiment II, treatments consisted of a no-tillage in natural rangeland, burned natural rangeland and natural rangeland. Forage turnip, black beans, common vetch, and corn were used in rotation in the treatments with crops in the no-tillage during study period. The treatments with crops and the burned rangeland and natural rangeland were compared to a bare soil control, without cultivation and without fertilization. Increasing fertilization rates increased organic carbon content, soil resistance to disintegration, and the macropore volume of the soil, due to the increase in the dry mass of the crops, resulting in an important reduction in water erosion. The exponential model of the ŷ = ae-bx type satisfactorily described the reduction in water and soil losses in accordance with the increase in fertilization rate and also described the decrease in soil losses in accordance with the increase in dry mass of the crops. Water erosion occurred in the following increasing intensity: in natural rangeland, in cultivated natural rangeland, and in burned natural rangeland. Water erosion had less effect on water losses than on soil losses, regardless of the soil management practices.

  2. [Assessment of the impacts of soil erosion on water environment based on the integration of soil erosion process and landscape pattern].

    Science.gov (United States)

    Liu, Yu; Wu, Bing-Fang; Zeng, Yuan; Zhang, Lei

    2013-09-01

    The integration of the effects of landscape pattern to the assessment of the impacts of soil erosion on eco-environmental is of practical significance in methodological prospect, being able to provide an approach for identifying water body's sediment source area, assessing the potential risks of sediment export of on-site soil erosion to the target water body, and evaluating the capacity of regional landscape pattern in preventing soil loss. In this paper, the RUSLE model was applied to simulate the on-site soil erosion rate. With the consideration of the soil retention potential of vegetation cover and topography, a quantitative assessment was conducted on the impacts of soil erosion in the water source region of the middle route for South-to-North Water Transfer Project on rivers and reservoirs by delineating landscape pattern at point (or cell) scale and sub-watershed level. At point (or grid cell) scale, the index of soil erosion impact intensity (I) was developed as an indicator of the potential risk of sediment export to the water bodies. At sub-watershed level, the landscape leakiness index (LI) was employed to indicate the sediment retention capacity of a given landscape pattern. The results revealed that integrating the information of landscape pattern and the indices of soil erosion process could spatially effectively reflect the impact intensity of in situ soil erosion on water bodies. The LI was significantly exponentially correlated to the mean sediment retention capacity of landscape and the mean vegetation coverage of watershed, and the sediment yield at sub-watershed scale was significantly correlated to the LI in an exponential regression. It could be concluded that the approach of delineating landscape pattern based on soil erosion process and the integration of the information of landscape pattern with its soil retention potential could provide a new approach for the risk evaluation of soil erosion.

  3. Revisiting classic water erosion models in drylands: The strong impact of biological soil crusts

    Science.gov (United States)

    Bowker, M.A.; Belnap, J.; Bala, Chaudhary V.; Johnson, N.C.

    2008-01-01

    Soil erosion and subsequent degradation has been a contributor to societal collapse in the past and is one of the major expressions of desertification in arid regions. The revised universal soil loss equation (RUSLE) models soil lost to water erosion as a function of climate erosivity (the degree to which rainfall can result in erosion), topography, soil erodibility, and land use/management. The soil erodibility factor (K) is primarily based upon inherent soil properties (those which change slowly or not at all) such as soil texture and organic matter content, while the cover/management factor (C) is based on several parameters including biological soil crust (BSC) cover. We examined the effect of two more precise indicators of BSC development, chlorophyll a and exopolysaccharides (EPS), upon soil stability, which is closely inversely related to soil loss in an erosion event. To examine the relative influence of these elements of the C factor to the K factor, we conducted our investigation across eight strongly differing soils in the 0.8 million ha Grand Staircase-Escalante National Monument. We found that within every soil group, chlorophyll a was a moderate to excellent predictor of soil stability (R2 = 0.21-0.75), and consistently better than EPS. Using a simple structural equation model, we explained over half of the variance in soil stability and determined that the direct effect of chlorophyll a was 3?? more important than soil group in determining soil stability. Our results suggest that, holding the intensity of erosive forces constant, the acceleration or reduction of soil erosion in arid landscapes will primarily be an outcome of management practices. This is because the factor which is most influential to soil erosion, BSC development, is also among the most manageable, implying that water erosion in drylands has a solution. ?? 2008 Elsevier Ltd.

  4. [Influence factors of deposition induced by melt water erosion in Naqu region, China].

    Science.gov (United States)

    Feng, Jun-yuan; Cai, Qiang-guo; Li, Zhao-xia; Sun, Li-ying

    2015-02-01

    Melt water erosion is one of the important soil erosion forms caused by the melt water from glacier and snow in high altitude cold areas of China. This paper investigated the influencing factors of deposition caused by melt water erosion in Naqu region. Alluvial fan ratio was presented as an index to characterize the degree of the deposition induced by melt water erosion. Minimum polygon was determined based on spatial overlay technology of Geographic Information System (GIS). The regression equation between the deposition index and the influencing factors was established through the stepwise regression analysis based on minimum polygon. Key influencing factors were identified according to the stepwise regression equation. The results showed that large amounts of alluvial fan were observed in Naqu region; extensive alluvial fans were centered at gentle slope areas in the central part of Naqu region with great spatial differences; alluvial fans were mainly distributed at valley exits, most of which were at large scale with vast differences in area and thickness. Wind speed, normalized difference vegetation index (NDVI), K value of soil erodibility, annual temperature range and the steep slope area ratio were identified as the key influencing factors on the deposition induced by melt water erosion in the studied area. Index of deposition was positively correlated with the wind speed and NDVI, and showed negative relationships with the K value of soil erodibility, the annual temperature range and steep slope area ratio.

  5. Effects of soil management techniques on soil water erosion in apricot orchards.

    Science.gov (United States)

    Keesstra, Saskia; Pereira, Paulo; Novara, Agata; Brevik, Eric C; Azorin-Molina, Cesar; Parras-Alcántara, Luis; Jordán, Antonio; Cerdà, Artemi

    2016-05-01

    Soil erosion is extreme in Mediterranean orchards due to management impact, high rainfall intensities, steep slopes and erodible parent material. Vall d'Albaida is a traditional fruit production area which, due to the Mediterranean climate and marly soils, produces sweet fruits. However, these highly productive soils are left bare under the prevailing land management and marly soils are vulnerable to soil water erosion when left bare. In this paper we study the impact of different agricultural land management strategies on soil properties (bulk density, soil organic matter, soil moisture), soil water erosion and runoff, by means of simulated rainfall experiments and soil analyses. Three representative land managements (tillage/herbicide/covered with vegetation) were selected, where 20 paired plots (60 plots) were established to determine soil losses and runoff. The simulated rainfall was carried out at 55mmh(-1) in the summer of 2013 (soil moisture) for one hour on 0.25m(2) circular plots. The results showed that vegetation cover, soil moisture and organic matter were significantly higher in covered plots than in tilled and herbicide treated plots. However, runoff coefficient, total runoff, sediment yield and soil erosion were significantly higher in herbicide treated plots compared to the others. Runoff sediment concentration was significantly higher in tilled plots. The lowest values were identified in covered plots. Overall, tillage, but especially herbicide treatment, decreased vegetation cover, soil moisture, soil organic matter, and increased bulk density, runoff coefficient, total runoff, sediment yield and soil erosion. Soil erosion was extremely high in herbicide plots with 0.91Mgha(-1)h(-1) of soil lost; in the tilled fields erosion rates were lower with 0.51Mgha(-1)h(-1). Covered soil showed an erosion rate of 0.02Mgha(-1)h(-1). These results showed that agricultural management influenced water and sediment dynamics and that tillage and herbicide

  6. USLE-Based Assessment of Soil Erosion by Water in the Nyabarongo River Catchment, Rwanda.

    Science.gov (United States)

    Karamage, Fidele; Zhang, Chi; Kayiranga, Alphonse; Shao, Hua; Fang, Xia; Ndayisaba, Felix; Nahayo, Lamek; Mupenzi, Christophe; Tian, Guangjin

    2016-08-20

    Soil erosion has become a serious problem in recent decades due to unhalted trends of unsustainable land use practices. Assessment of soil erosion is a prominent tool in planning and conservation of soil and water resource ecosystems. The Universal Soil Loss Equation (USLE) was applied to Nyabarongo River Catchment that drains about 8413.75 km² (33%) of the total Rwanda coverage and a small part of the Southern Uganda (about 64.50 km²) using Geographic Information Systems (GIS) and Remote Sensing technologies. The estimated total annual actual soil loss was approximately estimated at 409 million tons with a mean erosion rate of 490 t·ha(-1)·y(-1) (i.e., 32.67 mm·y(-1)). The cropland that occupied 74.85% of the total catchment presented a mean erosion rate of 618 t·ha(-1)·y(-1) (i.e., 41.20 mm·y(-1)) and was responsible for 95.8% of total annual soil loss. Emergency soil erosion control is required with a priority accorded to cropland area of 173,244 ha, which is extremely exposed to actual soil erosion rate of 2222 t·ha(-1)·y(-1) (i.e., 148.13 mm·y(-1)) and contributed to 96.2% of the total extreme soil loss in the catchment. According to this study, terracing cultivation method could reduce the current erosion rate in cropland areas by about 78%. Therefore, the present study suggests the catchment management by constructing check dams, terracing, agroforestry and reforestation of highly exposed areas as suitable measures for erosion and water pollution control within the Nyabarongo River Catchment and in other regions facing the same problems.

  7. USLE-Based Assessment of Soil Erosion by Water in the Nyabarongo River Catchment, Rwanda

    Directory of Open Access Journals (Sweden)

    Fidele Karamage

    2016-08-01

    Full Text Available Soil erosion has become a serious problem in recent decades due to unhalted trends of unsustainable land use practices. Assessment of soil erosion is a prominent tool in planning and conservation of soil and water resource ecosystems. The Universal Soil Loss Equation (USLE was applied to Nyabarongo River Catchment that drains about 8413.75 km2 (33% of the total Rwanda coverage and a small part of the Southern Uganda (about 64.50 km2 using Geographic Information Systems (GIS and Remote Sensing technologies. The estimated total annual actual soil loss was approximately estimated at 409 million tons with a mean erosion rate of 490 t·ha−1·y−1 (i.e., 32.67 mm·y−1. The cropland that occupied 74.85% of the total catchment presented a mean erosion rate of 618 t·ha−1·y−1 (i.e., 41.20 mm·y−1 and was responsible for 95.8% of total annual soil loss. Emergency soil erosion control is required with a priority accorded to cropland area of 173,244 ha, which is extremely exposed to actual soil erosion rate of 2222 t·ha−1·y−1 (i.e., 148.13 mm·y−1 and contributed to 96.2% of the total extreme soil loss in the catchment. According to this study, terracing cultivation method could reduce the current erosion rate in cropland areas by about 78%. Therefore, the present study suggests the catchment management by constructing check dams, terracing, agroforestry and reforestation of highly exposed areas as suitable measures for erosion and water pollution control within the Nyabarongo River Catchment and in other regions facing the same problems.

  8. Spatial distribution of water erosion risk in a watershed with eucalyptus and Atlantic Forest

    Directory of Open Access Journals (Sweden)

    Junior Cesar Avanzi

    2013-10-01

    Full Text Available The process of water erosion occurs in watersheds throughout the world and it is strongly affected by anthropogenic influences. Thus, the knowledge of these processes is extremely necessary for planning of conservation efforts. This study was performed in an experimental forested watershed in order to predict the average potential annual soil loss by water erosion using the Universal Soil Loss Equation (USLE and a Geographic Information System (GIS, and then compared with soil loss tolerance. All the USLE factors were generated in a distributed approach employing a GIS tool. The layers were multiplied in the GIS framework in order to predict soil erosion rates. Results showed that the average soil loss was 6.2 Mg ha-1 yr-1. Relative to soil loss tolerance, 83% of the area had an erosion rate lesser than the tolerable value. According to soil loss classes, 49% of the watershed had erosion less than 2.5 Mg ha-1 yr-1. However, about 8.7% of the watershed had erosion rates greater than 15 Mg ha-1 yr-1, being mainly related to Plinthosol soil class and roads, thus requiring special attention for the improvement of sustainable management practices for such areas. Eucalyptus cultivation was found to have soil loss greater than Atlantic Forest. Thus, an effort should be made to bring the erosion rates closer to the native forest. Implementation of the USLE model in a GIS framework was found to be a simple and useful tool for predicting the spatial variation of soil erosion risk and identifying critical areas for conservation efforts.

  9. Water erosion and soil water infiltration in different stages of corn development and tillage systems

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    Daniel F. de Carvalho

    2015-11-01

    Full Text Available ABSTRACTThis study evaluated soil and water losses, soil water infiltration and infiltration rate models in soil tillage systems and corn (Zea mays, L. development stages under simulated rainfall. The treatments were: cultivation along contour lines, cultivation down the slope and exposed soil. Soil losses and infiltration in each treatment were quantified for rains applied using a portable simulator, at 0, 30, 60 and 75 days after planting. Infiltration rates were estimated using the models of Kostiakov-Lewis, Horton and Philip. Based on the obtained results, the combination of effects between soil tillage system and corn development stages reduces soil and water losses. The contour tillage system promoted improvements in soil physical properties, favoring the reduction of erosion in 59.7% (water loss and 86.6% (soil loss at 75 days after planting, and the increase in the stable infiltration rate in 223.3%, compared with the exposed soil. Associated to soil cover, contour cultivation reduces soil and water losses, and the former is more influenced by management. Horton model is the most adequate to represent soil water infiltration rate under the evaluated conditions.

  10. Snowmelt water drives higher soil erosion than rainfall water in a mid-high latitude upland watershed

    Science.gov (United States)

    Wu, Yuyang; Ouyang, Wei; Hao, Zengchao; Yang, Bowen; Wang, Li

    2018-01-01

    The impacts of precipitation and temperature on soil erosion are pronounced in mid-high latitude areas, which lead to seasonal variations in soil erosion. Determining the critical erosion periods and the reasons behind the increased erosion loads are essential for soil management decisions. Hence, integrated approaches combining experiments and modelling based on field investigations were applied to investigate watershed soil erosion characteristics and the dynamics of water movement through soils. Long-term and continuous data for surface runoff and soil erosion variation characteristics of uplands in a watershed were observed via five simulations by the Soil and Water Assessment Tool (SWAT). In addition, laboratory experiments were performed to quantify the actual soil infiltrabilities in snowmelt seasons (thawed treatment) and rainy seasons (non-frozen treatment). The results showed that over the course of a year, average surface runoff and soil erosion reached peak values of 31.38 mm and 1.46 t ha-1 a-1, respectively, in the month of April. They also ranked high in July and August, falling in the ranges of 23.73 mm to 24.91 mm and 0.55 t ha-1 a-1 to 0.59 t ha-1 a-1, respectively. With the infiltration time extended, thawed soils showed lower infiltrabilities than non-frozen soils, and the differences in soil infiltration amounts between these two were considerable. These results highlighted that soil erosion was very closely and positively correlated with surface runoff. Soil loss was higher in snowmelt periods than in rainy periods due to the higher surface runoff in early spring, and the decreased soil infiltrability in snowmelt periods contributed much to this higher surface runoff. These findings are helpful for identification of critical soil erosion periods when making soil management before critical months, especially those before snowmelt periods.

  11. Water erosion in no-tillage monoculture and intercropped systems along contour lines

    Directory of Open Access Journals (Sweden)

    Ildegardis Bertol

    2013-04-01

    Full Text Available Water erosion is the major cause of soil and water losses and the main factor of degradation of agricultural areas. The objective of this work was to quantify pluvial water erosion from an untilled soil with crop rows along the contour, in 2009 and 2010, on a Humic Dystrupept, with the following treatments: a maize monoculture; b soybean monoculture; c common bean monoculture; d intercropped maize and bean, exposed to four simulated rainfall tests of on hour at controlled intensity (64 mm h-1. The first test was applied 18 days after sowing and the others; 39, 75 and 120 days after the first test. The crop type influenced soil loss through water erosion in the simulated rainfall tests 3 and 4; soybean was most effective in erosion control in test 3, however, in test 4, maize was more effective. Water loss was influenced by the crop type in test 3 only, where maize and soybean were equally effective, with less runoff than from the other crops. The soil loss rate varied during the runoff sampling period in different ways, demonstrating a positive linear relationship between soil and water loss, in the different rainfall tests.

  12. Control of erosion and water pollution during exploitation of the Meirama lignites. Control de la erosion y contaminacion de las aguas en la explotacion de lignitos de Meirama

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Jimeno, E. (Lignitos de Meirama, S.A. (Spain))

    1989-01-01

    The required reclamation of land disturbed by surface coal mining often results in the creation of some slopes and soils that are prone to rapid erosion and sediment production. The are two general methods of preventing or controlling soil erosion from rainfall and water running. These two methods are the building of mechanical structures and covering the soil with live vegetation. This paper discusses the water control methods, the design of the drainage and acid water treatment plant of Lignitos de Meirama. 5 refs., 10 figs.

  13. Rainfall simulation and Structure-from-Motion photogrammetry for the analysis of soil water erosion in Mediterranean vineyards

    NARCIS (Netherlands)

    Prosdocimi, Massimo; Burguet, Maria; Prima, Di Simone; Sofia, Giulia; Terol, Enric; Rodrigo Comino, Jesús; Cerda Bolinches, Artemio; Tarolli, Paolo

    2017-01-01

    Soil water erosion is a serious problem, especially in agricultural lands. Among these, vineyards deserve attention, because they constitute for the Mediterranean areas a type of land use affected by high soil losses. A significant problem related to the study of soil water erosion in these areas

  14. BIOLOGICAL WAYS OF STRUGGLE AGAINST WATER EROSION ON ARABLE SLOPES OF THE CENTRAL RUSSIA

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    Tatyana ANISIMOVA

    2013-12-01

    Full Text Available In article are proved a choice of ways of struggle against water erosion of arable slopes on the basis of harnessing the potential of bio-based agrocenosis. Efficiency of use long-term lupine in quality green manure and phyto-ameliorant on eroded soddy-podzolic sandy soils of the Vladimir area is shown.

  15. Soil and water temperature effects on the fluvial erosion of cohesive sediments

    Science.gov (United States)

    Akinola, A.; Wynn-Thompson, T.; Olgun, G.

    2016-12-01

    Sediment is one of the leading causes of water quality impairment in US streams and rivers (Wood and Armitage 1997; USEPA 2000; Bryce et al., 2010). Although sediment mobilization from the and transport through fluvial systems is a natural process, human activities, as a result of urbanization and climate change, alter the natural hydrologic and hydraulic characteristic of watersheds, leading to extreme erosion and sedimentation. Apart from higher flows, however, urbanization leads to elevated stream temperatures and, in combination with other anthropogenic influences such as hydropower operations, reservoir discharges and industrial cooling water, result in water and soil temperatures well above the expected seasonal temperature regime. In laboratory experiments, a higher water temperature was positively correlated with erosion rates (Grissinger, 1966; Cristensen and Das 1974; Parks, 2012) but this phenomenon is still poorly understood. Additionally, the effect of soil temperature on the fluvial erosion of cohesive soils has never been studied before; therefore, this research explores the relationship between soil and water temperature on cohesive soil erosion rate. Remolded montmorillonite, vermiculite and illite/kaolinite-dominated soils were tested in an 8 m x 1 m x 0.4 m recirculating flume at four combinations of soil temperatures and water temperatures (40C water and 40C soil, 40C water and 150C soil, 250C water and 250C soil, 250C water and 400C soil) representing typical winter and summer field conditions, as well as increased soil temperatures due to contact with urban infrastructure, such as bridge piers or foundations. Soils were compacted at their respective maximum dry density and optimum moisture content, based on Proctor tests (ASTM D698) and then eroded for 10-15 minutes at a boundary shear stress of 4 Pa. Velocity profiles and distance to the soil surface were measured continuously using a profiling acoustic doppler velocimeter. Differences in

  16. Cavitation pitting and erosion of aluminum 6061-T6 in mineral oil water

    Science.gov (United States)

    Rao, B. C. S.; Buckley, D. H.

    1983-01-01

    Cavitation erosion studies of aluminum 6061-T6 in mineral oil and in ordinary tap water are presented. The maximum erosion rate (MDPR, or mean depth of penetration rate) in mineral oil was about four times that in water. The MDPR in mineral oil decreased continuously with time, but the MDPR in water remained approximately constant. The cavitation pits in mineral oil were of smaller diameter and depth than the pits in water. Treating the pits as spherical segments, we computed the radius r of the sphere. The logarithm of h/a, where h is the pit depth and 2a is the top width of the pit, was linear when plotted against the logarithm of 2r/h - 1.

  17. Nutrient and Organic Carbon Losses, Enrichment Rate, and Cost of Water Erosion

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    Ildegardis Bertol

    Full Text Available ABSTRACT Soil erosion from water causes loss of nutrients and organic carbon, enriches the environment outside the erosion site, and results in costs. The no-tillage system generates increased nutrient and C content in the topsoil and, although it controls erosion, it can produce a more enriched runoff than in the conventional tillage system. This study was conducted in a Humic Cambisol in natural rainfall from 1997 to 2012 to quantify the contents and total losses of nutrients and organic C in soil runoff, and to calculate the enrichment rates and the cost of these losses. The treatments evaluated were: a soil with a crop, consisting of conventional tillage with one plowing + two harrowings (CT, minimum tillage with one chisel plowing + one harrowing (MT, and no tillage (NT; and b bare soil: one plowing + two harrowings (BS. In CT, MT, and NT, black oat, soybean, vetch, corn, turnip, and black beans were cultivated. Over the 15 years, 15.5 Mg ha-1 of limestone, 525 kg ha-1 of N (urea, 1,302 kg ha-1 of P2O5 (triple superphosphate, and 1,075 kg ha-1 of K2O (potassium chloride were used in the soil. The P, K, Ca, Mg, and organic C contents in the soil were determined and also the P, K, Ca, and Mg sediments in the runoff water. From these contents, the total losses, the enrichment rates (ER, and financial losses were calculated. The NT increased the P, K, and organic C contents in the topsoil. The nutrients and organic C content in the runoff from NT was greater than from CT, showing that NT was not a fully conservationist practice for soil. The linear model y = a + bx fit the data within the level of significance (p≤0.01 when the values of P, K, and organic C in the sediments from erosion were related to those values in the soil surface layer. The nutrient and organic C contents were higher in the sediments from erosion than in the soil where the erosion originated, generating values of ER>1 for P, K, and organic C. The value of the total losses

  18. Prediction of soil water erosion risk within GIS-case study of Beni Amrane Dam catchment (North of Algeria)

    Science.gov (United States)

    Touahir, S.; Khenter, K.; Remini, B.; Saad, H.

    2017-08-01

    Isser River is one of North Algeria’s major resources. It is vulnerable to water soil erosion because of favourable conjunctions of different geomorphological, hydro-climatic and lithologic factors. This case study has been carried out on the Beni Amrane dam Catchment, which is located in the bottom of Isser River, in North Algeria. The study involves a mapping of main factors of water erosion: rainfall erosivity, soil erodibility, slope and land use. Essentially a data mapping specification analysis shows, on each factor, how to identify the areas that are prone to water erosion. 04 classes of multifactorial vulnerability to water erosion have been identified: areas with low vulnerability (10 per cent); area with middle vulnerability (49 per cent); areas with high and very high vulnerability (38 per cent and 3 per cent). This could be a first guidance document for a rational use of land in the region and better secure the Beni Amrane dam against reservoir siltation.

  19. Modelling threats to water quality from fire suppression chemicals and post-fire erosion

    Science.gov (United States)

    Hyde, Kevin; Ziemniak, Chris; Elliot, William; Samuels, William

    2014-05-01

    Misapplication of fire retardant chemicals into streams and rivers may threaten aquatic life. The possible threat depends on the contaminant concentration that, in part, is controlled by dispersion within flowing water. In the event of a misapplication, methods are needed to rapidly estimate the chemical mass entering the waterway and the dispersion and transport within the system. Here we demonstrate a new tool that calculates the chemical mass based on aircraft delivery system, fire chemical type, and stream and intersect geometry. The estimated mass is intended to be transferred into a GIS module that uses real-time stream data to map and simulate the dispersion and transport downstream. This system currently accounts only for aqueous transport. We envision that the GIS module can be modified to incorporate sediment transport, specifically to model movement of sediments from post-fire erosion. This modification could support assessment of threats of post-fire erosion to water quality and water supply systems.

  20. Water erosion susceptibility mapping by applying Stochastic Gradient Treeboost to the Imera Meridionale River Basin (Sicily, Italy)

    Science.gov (United States)

    Angileri, Silvia Eleonora; Conoscenti, Christian; Hochschild, Volker; Märker, Michael; Rotigliano, Edoardo; Agnesi, Valerio

    2016-06-01

    Soil erosion by water constitutes a serious problem affecting various countries. In the last few years, a number of studies have adopted statistical approaches for erosion susceptibility zonation. In this study, the Stochastic Gradient Treeboost (SGT) was tested as a multivariate statistical tool for exploring, analyzing and predicting the spatial occurrence of rill-interrill erosion and gully erosion. This technique implements the stochastic gradient boosting algorithm with a tree-based method. The study area is a 9.5 km2 river catchment located in central-northern Sicily (Italy), where water erosion processes are prevalent, and affect the agricultural productivity of local communities. In order to model soil erosion by water, the spatial distribution of landforms due to rill-interrill and gully erosion was mapped and 12 environmental variables were selected as predictors. Four calibration and four validation subsets were obtained by randomly extracting sets of negative cases, both for rill-interrill erosion and gully erosion models. The results of validation, based on receiving operating characteristic (ROC) curves, showed excellent to outstanding accuracies of the models, and thus a high prediction skill. Moreover, SGT allowed us to explore the relationships between erosion landforms and predictors. A different suite of predictor variables was found to be important for the two models. Elevation, aspect, landform classification and land-use are the main controlling factors for rill-interrill erosion, whilst the stream power index, plan curvature and the topographic wetness index were the most important independent variables for gullies. Finally, an ROC plot analysis made it possible to define a threshold value to classify cells according to the presence/absence of the two erosion processes. Hence, by heuristically combining the resulting rill-interrill erosion and gully erosion susceptibility maps, an integrated water erosion susceptibility map was created. The

  1. Soil water erosion on Mediterranean vineyards. A review based on published data

    Science.gov (United States)

    Prosdocimi, Massimo; Cerdà, Artemi; Tarolli, Paolo

    2015-04-01

    Soil water erosion on cultivated lands is a severe threat to soil resources in the world (Leh et al., 2013; Zhao et al., 2013). In particular, Mediterranean areas deserve a particular attention because of their edaphic, topographic and climatic conditions. Among the cultivated lands, concerns have arisen about vineyards because, aside representing one of the most important crop in terms of income and employment, they also have proven to be the form of agricultural land that causes one of the highest soil losses (Tropeano et al., 1984; Leonard and Andrieux, 1998; Ferrero et al., 2005; Cerdà et al., 2007; Blavet et al., 2009; Casalí et al., 2009; Novara et al., 2011; Martínez Casasnovas et al., 2013; Ruiz Colmenero et al., 2013; Tarolli et al., 2014). Although the topic of soil water erosion on vineyards has been studied, it still raises uncertainties. These are due to the i) high complexity of processes involved, ii) different methodologies used to analyze them and iii) analyses carried out at different spatial and temporal scales. At this regard, this work aims to evaluate the impact of factors controlling erosion such as rainfall characteristics, topography, soil properties and soil and water conservation techniques. Data derived from experimental plots have been reviewed. At first, what emerges is the difficulty of comparing erosion rates obtained with different methodologies and at different spatial scales. Secondly, all the factors demonstrate to have a strong impact on soil erosion but a 'general rule' upon which to consider one factor always predominant over the others does not come out. Therefore, this work supports the importance of monitoring soil water erosion by field measurements to better understand the relationship between the factors. Variables like rainfall characteristics, topography and soil properties are much more difficult to modify than the soil and water management techniques. Hence, future researches are needed to both recommend the best

  2. The effects of mulching on soil erosion by water. A review based on published data

    Science.gov (United States)

    Prosdocimi, Massimo; Jordán, Antonio; Tarolli, Paolo; Cerdà, Artemi

    2016-04-01

    Among the soil conservation practices that have been recently implemented, mulching has been successfully applied in different contexts (Jordán et al., 2011), such as agricultural lands (García-Orenes et al. 2009; Prosdocimi et al., 2016), fire-affected areas (Prats et al., 2014; Robichaud et al., 2013) and anthropic sites (Hayes et al., 2005), to reduce water and soil losses rates. In these contexts, soil erosion by water is a serious problem, especially in semi-arid and semi-humid areas of the world (Cerdà et al., 2009; Cerdan et al., 2010; Sadeghi et al., 2015). Although soil erosion by water consists of physical processes that vary significantly in severity and frequency according to when and where they occur, they are also strongly influenced by anthropic factors such as unsustainable farming practices and land-use changes on large scales (Cerdà, 1994; Montgomery, 2007). Although the beneficial effects of mulching are known, their quantification needs further research, especially in those areas where soil erosion by water represents a severe threat. In literature, there are still some uncertainties about how to maximize the effectiveness of mulching in the reduction of soil and water loss rates. First, the type of choice of the vegetative residues is fundamental and drives the application rate, cost, and consequently, its effectiveness. Second, it is important to assess application rates suitable for site-specific soil and environment conditions. The percentage of area covered by mulch is another important aspect to take into account, because it has proven to influence the reduction of soil loss. And third, the role played by mulching at catchment scale, where it plays a key role as barrier for breaking sediment and runoff connectivity. Given the seriousness of soil erosion by water and the uncertainties that still concern the correct use of mulching, this work aims to evaluate the effects of mulching on soil erosion rates and water losses in agricultural

  3. Physicochemical effects of temperature and water chemistry on cohesive channel erosion

    Science.gov (United States)

    Wynn-Thompson, T.; Hoomehr, S.; Parks, O.; Eick, M.

    2013-12-01

    One potential unforeseen consequence urbanization and climate change is accelerated stream channel erosion due to increased stream temperatures and changes in stream chemistry, which affect the surface potential and hence the stability of soil colloids. Summer thunderstorms in urban watersheds can increase stream temperature more than 7 degC and the impact of global warming on average stream temperature is already evident in some stream systems. The goal of this research was to evaluate the impact of changes in stream chemistry commonly observed in urban watersheds, and expected to occur due to climate change, on the fluvial erosion of cohesive streambank soils. We hypothesized that increases in stream temperature and changes in stream pH and salt concentrations alter the surface potential of clay particles, affecting soil erodibility. We tested this hypothesis by measuring the erosion rate of two riparian soils dominated by different common phyllosilicate clays in a recirculating hydraulic flume. Two pH levels (6, 8), three water temperatures (10 degC, 20 degC, 30 degC), and two NaCl concentrations (5 mg/l, 5 g/l) were analyzed. Velocity profiles and the distance to the soil sample were measured using a Sontek Vectrino II acoustic Doppler profiler. Additionally, zetapotential was measured to determine if erosion rates were correlated to changes in clay surface potential due to varying water chemistry. Initial study results indicated significant increases in erosion rates for both clay types with decreasing pH and increasing water temperature; temperature effects were more significant than pH effects. Changes in erosion rates with salt concentration were only significant for the soil with montmorillonite clay. While the research is ongoing, these initial results could have wide-ranging implications for climate change and urban stormwater management. Assuming climate change will result in higher stream temperatures and lower stream pH, streambank erosion could

  4. Georeferenced measurement of soil EC as a tool to detect susceptible areas to water erosion.

    Science.gov (United States)

    Fabian Sallesses, Leonardo; Aparicio, Virginia Carolina; Costa, Jose Luis

    2017-04-01

    The Southeast region of Buenos Aires Province, Argentina, is one of the main region for the cultivation of potato (Solanum tuberosum L.) in that country. The implementation of complementary irrigation for potato cultivation meant an increase in yield of up to 60%. Therefore, all potato production in the region is under irrigation. In this way, the area under central pivot irrigation has increased to 150% in the last two decades. The water used for irrigation in that region is underground with a high concentration of sodium bicarbonate. The combination of irrigation and rain increases the sodium absorption ratio of soil (SARs), consequently raising the clay dispersion and reducing infiltration. A reduction in infiltration means greater partitioning of precipitation into runoff. The degree of slope of the terrain, added to its length, increases the erosive potential of runoff water. The content of dissolved salts, in combination with the water content, affect the apparent Electrical Conductivity of the soil (EC), which is directly related to the concentration of Na + 2 in the soil solution. In August 2016, severe rill erosion was detected in a productive plot of 300 ha. The predecessor crop was a potato under irrigation campaign. However the history of the lot consists of various winter and summer crops, always made in dry land and no till. Cumulative rainfall from harvest to erosion detection (four months) was 250 mm. A georeferenced EC measurement was performed using the Verys 3100® contact sensor. With the data obtained, a geostatistical analysis was performed using Kriging spatial interpolation. The maps obtained were processed, dividing them into 4 EC ranges. The values and amplitude of the CEa ranges for each lot were determined according to the distribution observed in the generated histograms. It was observed a distribution of elevated EC ranges and consequently of a higher concentration of Na+ 2 coincident with the irrigation areas of the pivots. These

  5. Soil water erosion under different cultivation systems and different fertilization rates and forms over 10 years

    Directory of Open Access Journals (Sweden)

    Ildegardis Bertol

    2014-12-01

    Full Text Available The action of rain and surface runoff together are the active agents of water erosion, and further influences are the soil type, terrain, soil cover, soil management, and conservation practices. Soil water erosion is low in the no-tillage management system, being influenced by the amount and form of lime and fertilizer application to the soil, among other factors. The aim was to evaluate the effect of the form of liming, the quantity and management of fertilizer application on the soil and water losses by erosion under natural rainfall. The study was carried out between 2003 and 2013 on a Humic Dystrupept soil, with the following treatments: T1 - cultivation with liming and corrective fertilizer incorporated into the soil in the first year, and with 100 % annual maintenance fertilization of P and K; T2 - surface liming and corrective fertilization distributed over five years, and with 75 % annual maintenance fertilization of P and K; T3 - surface liming and corrective fertilization distributed over three years, and with 50 % annual maintenance fertilization of P and K; T4 - surface liming and corrective fertilization distributed over two years, and with 25 % annual maintenance fertilization of P and K; T5 - fallow soil, without liming or fertilization. In the rotation the crops black oat (Avena strigosa , soybean (Glycine max , common vetch (Vicia sativa , maize (Zea mays , fodder radish (Raphanus sativus , and black beans (Phaseolus vulgaris . The split application of lime and mineral fertilizer to the soil surface in a no-tillage system over three and five years, results in better control of soil losses than when split in two years. The increase in the amount of fertilizer applied to the soil surface under no-tillage cultivation increases phytomass production and reduces soil loss by water erosion. Water losses in treatments under no-tillage cultivation were low in all crop cycles, with a similar behavior as soil losses.

  6. Soil Organic Carbon Redistribution by Water Erosion - The Role of CO2 Emissions for the Carbon Budget

    NARCIS (Netherlands)

    Wang, X.; Cammeraat, E.L.H.; Romeijn, P.; Kalbitz, K.

    2014-01-01

    A better process understanding of how water erosion influences the redistribution of soil organic carbon (SOC) is sorely needed to unravel the role of soil erosion for the carbon (C) budget from local to global scales. The main objective of this study was to determine SOC redistribution and the

  7. Sustainable soil and water resources: modelling soil erosion and its impact on the environment

    OpenAIRE

    Sander, Graham C.; T. Zheng; Heng, P.; Zhong, Y.; Barry, David Andrew

    2011-01-01

    With the projected increase in world population to 9 billion by 2050, along with per capita income growth, the demand for land and water resources is going to increase significantly. Conversion of land to intensive agriculture has led to dramatic decreases in plant, animal and insect biodiversity, with approximately 40% of the world’s land surface now covered by croplands and pastures. Intensive agricultural practices cause erosion and lead to transport of soil particles and associated sorbed...

  8. Characteristics of water erosion and conservation practice in arid regions of Central Asia: Xinjiang Province, China as an example

    Directory of Open Access Journals (Sweden)

    Wentai Zhang

    2015-06-01

    Full Text Available Located in the inland arid area of Central Asia and northwest China, Xinjiang has recently received heightened concerns over soil water erosion, which is highly related with the sustainable utilization of barren soil and limited water resources. Data from the national soil erosion survey of China (1985–2011 and Xinjiang statistical yearbook (2000–2010 was used to analyze the trend, intensity, and serious soil water erosion regions. Results showed that the water erosion area in Xinjiang was 87.6×103 km2 in 2011, mainly distributed in the Ili river valley and the northern and southern Tian Mountain. Soil erosion gradient was generally slight and the average erosion modulus was 2184 t/(km2 a. During the last 26 years, the water erosion area in Xinjiang decreased by 23.2%, whereas the intensity was still increasing. The driving factors from large to small impact included: population boom and human activities>vegetation degradation>rainfall and climate change>topography and soil erodibility>tectonics movement. Soil water erosion resulted in eco-environmental and socioeconomic losses, such as destroying farmland and grassland, triggering floods, sedimentation of reservoirs, damaging transportation and irrigation facilities, and aggravating poverty. A landscape ecological design approach is suggested for integrated control of soil erosion. Currently, an average of 2.07×103 km2 of formerly eroded area is conserved each year. This study highlighted the importance and longevity of soil and water conservation efforts in Xinjiang, and offered some suggestions on ecological restoration and combating desertification in arid regions of Central Asia.

  9. Soil, water and nutrient losses by interrill erosion from green cane cultivation

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    Gilka Rocha Vasconcelos da Silva

    2012-06-01

    Full Text Available Interrill erosion occurs by the particle breakdown caused by raindrop impact, by particle transport in surface runoff, by dragging and suspension of particles disaggregated from the soil surface, thus removing organic matter and nutrients that are essential for agricultural production. Crop residues on the soil surface modify the characteristics of the runoff generated by rainfall and the consequent particle breakdown and sediment transport resulting from erosion. The objective of this study was to determine the minimum amount of mulch that must be maintained on the soil surface of a sugarcane plantation to reduce the soil, water and nutrient losses by decreasing interrill erosion. The study was conducted in Pradópolis, São Paulo State, in 0.5 x 1.0 m plots of an Oxisol, testing five treatments in four replications. The application rates were based on the crop residue production of the area of 1.4 kg m-2 (T1- no cane trash; T2-25 % of the cane trash; T3- 50 % trash; T4-75 % trash; T5-100 % sugarcane residues on the surface, and simulated rainfall was applied at an intensity of 65 mm h-1 for 60 min. Runoff samples were collected in plastic containers and soon after taken to the laboratory to quantify the losses of soil, water and nutrients. To minimize soil loss by interrill erosion, 75 % of the cane mulch must be maintained on the soil, to control water loss 50 % must be maintained and 25 % trash controls organic matter and nutrient losses. This information can contribute to optimize the use of this resource for soil conservation on the one hand and the production of clean energy in sugar and alcohol industries on the other.

  10. Mapping and Modelling Land Susceptibility to Water Erosion in Eastern Botswana

    Science.gov (United States)

    Olufunmilayo Akinyemi, Felicia; Mashame, Gofamodimo

    2017-04-01

    Soil loss by water erosion is a major environmental challenge globally and semi-arid environments are not exempted. This study employs a spatial modelling technique that applies the Revised Universal Soil Loss Equation (RUSLE) to estimate annual soil loss in the Palapye area of the Lotsane sub-basin in Eastern Botswana. Soil loss estimation within a GIS environment allows for the integration of datasets from various sources and enables the mapping of the spatial distribution of soil loss. With the high sensitivity of semi-arid areas to climate change, this study further investigates how rates of soil loss would vary using both historical (1990-2012) and near range 21st Century (2015-2028) under two IPCC Representative Concentration Pathways (RCPs): RCP4.5 and RCP8.5. Topography and vegetation cover seems to play a prominent role in soil loss as it occurs mostly along tracks and/or footpaths, bare land, river banks and on the steep hilly slopes in the south eastern part. For RCP 4.5, the highest projected average annual soil loss due to water erosion is 307 Mg ha-1 year-1, whereas, for RCP 8.5, the highest is 330 Mg ha-1 year-1. In general, projected soil losses are higher for RCP8.5 than for RCP4.5. This study aids the validation of empirical models and contributes to the understanding of soil erosion rates under present conditions and future climate.

  11. Spiders: water-driven erosive structures in the southern hemisphere of Mars.

    Science.gov (United States)

    Prieto-Ballesteros, Olga; Fernández-Remolar, David C; Rodríguez-Manfredi, José Antonio; Selsis, Franck; Manrubia, Susanna C

    2006-08-01

    Recent data from space missions reveal that there are ongoing climatic changes and erosive processes that continuously modify surface features of Mars. We have investigated the seasonal dynamics of a number of morphological features located at Inca City, a representative area at high southern latitude that has undergone seasonal processes. By integrating visual information from the Mars Orbiter Camera on board the Mars Global Surveyor and climatic cycles from a Mars' General Circulation Model, and considering the recently reported evidence for the presence of water-ice and aqueous precipitates on Mars, we propose that a number of the erosive features identified in Inca City, among them spiders, result from the seasonal melting of aqueous salty solutions.

  12. Surface water and erosion calculations to support the MDA G performance assessment

    Energy Technology Data Exchange (ETDEWEB)

    Springer, E.P.

    1997-03-01

    The performance of MDA G is dependent on surface hydrological and ecological processes because radionuclide transport by surface runoff can affect human and/or environmental receptors directly and the percolation for the subsurface radionuclide transport pathway is determined by the water balance in the near surface. For subsurface disposal of waste, surface soil erosion reduces the effectiveness of the surface cover and if wastes are exposed, then surface runoff can transport contaminants either in a soluble phase or sorbed to eroded soil particles. The objectives of this section are to estimate the effects at MDA G of surface runoff, soil erosion, and percolation. The conceptual and mathematical models will be reviewed, parameter estimation for the models will be presented and results and sensitivity analyses for a surface cover at MDA G will be presented.

  13. Lateral transport of soil carbon and land−atmosphere CO2 flux induced by water erosion in China

    Science.gov (United States)

    Yue, Yao; Ni, Jinren; Ciais, Philippe; Piao, Shilong; Wang, Tao; Huang, Mengtian; Borthwick, Alistair G. L.; Li, Tianhong; Wang, Yichu; Chappell, Adrian; Van Oost, Kristof

    2016-01-01

    Soil erosion by water impacts soil organic carbon stocks and alters CO2 fluxes exchanged with the atmosphere. The role of erosion as a net sink or source of atmospheric CO2 remains highly debated, and little information is available at scales larger than small catchments or regions. This study attempts to quantify the lateral transport of soil carbon and consequent land−atmosphere CO2 fluxes at the scale of China, where severe erosion has occurred for several decades. Based on the distribution of soil erosion rates derived from detailed national surveys and soil carbon inventories, here we show that water erosion in China displaced 180 ± 80 Mt C⋅y−1 of soil organic carbon during the last two decades, and this resulted a net land sink for atmospheric CO2 of 45 ± 25 Mt C⋅y−1, equivalent to 8–37% of the terrestrial carbon sink previously assessed in China. Interestingly, the “hotspots,” largely distributed in mountainous regions in the most intensive sink areas (>40 g C⋅m−2⋅y−1), occupy only 1.5% of the total area suffering water erosion, but contribute 19.3% to the national erosion-induced CO2 sink. The erosion-induced CO2 sink underwent a remarkable reduction of about 16% from the middle 1990s to the early 2010s, due to diminishing erosion after the implementation of large-scale soil conservation programs. These findings demonstrate the necessity of including erosion-induced CO2 in the terrestrial budget, hence reducing the level of uncertainty. PMID:27247397

  14. Lateral transport of soil carbon and land-atmosphere CO2 flux induced by water erosion in China.

    Science.gov (United States)

    Yue, Yao; Ni, Jinren; Ciais, Philippe; Piao, Shilong; Wang, Tao; Huang, Mengtian; Borthwick, Alistair G L; Li, Tianhong; Wang, Yichu; Chappell, Adrian; Van Oost, Kristof

    2016-06-14

    Soil erosion by water impacts soil organic carbon stocks and alters CO2 fluxes exchanged with the atmosphere. The role of erosion as a net sink or source of atmospheric CO2 remains highly debated, and little information is available at scales larger than small catchments or regions. This study attempts to quantify the lateral transport of soil carbon and consequent land-atmosphere CO2 fluxes at the scale of China, where severe erosion has occurred for several decades. Based on the distribution of soil erosion rates derived from detailed national surveys and soil carbon inventories, here we show that water erosion in China displaced 180 ± 80 Mt C⋅y(-1) of soil organic carbon during the last two decades, and this resulted a net land sink for atmospheric CO2 of 45 ± 25 Mt C⋅y(-1), equivalent to 8-37% of the terrestrial carbon sink previously assessed in China. Interestingly, the "hotspots," largely distributed in mountainous regions in the most intensive sink areas (>40 g C⋅m(-2)⋅y(-1)), occupy only 1.5% of the total area suffering water erosion, but contribute 19.3% to the national erosion-induced CO2 sink. The erosion-induced CO2 sink underwent a remarkable reduction of about 16% from the middle 1990s to the early 2010s, due to diminishing erosion after the implementation of large-scale soil conservation programs. These findings demonstrate the necessity of including erosion-induced CO2 in the terrestrial budget, hence reducing the level of uncertainty.

  15. Implications of sediment transport by subglacial water flow for interpreting contemporary glacial erosion rates

    Science.gov (United States)

    Beaud, Flavien; Flowers, Gwenn E.; Venditti, Jeremy G.

    2017-04-01

    The role of glaciers in landscape evolution is central to the interactions between climate and tectonic forces at high latitudes and in mountainous regions. Sediment yields from glacierized basins are used to quantify contemporary erosion rates on seasonal to decadal timescales, often under the assumption that subglacial water flow is the main contributor to these yields. Two recent studies have furthermore used such sediment fluxes to calibrate a glacial erosion rule, where erosion rate scales with ice sliding speed raised to a power greater than one. Subglacial sediment transport by water flow has however seldom been studied, thus the controls on sediment yield from glacierized basins remain enigmatic. To bridge this gap, we develop a 1-D model of morphodynamics in semi-circular bedrock-floored subglacial channels. We adapt a sediment conservation law from the fluvial literature, developed for both mixed bedrock / alluvial and alluvial conditions, to subglacial channels. Channel evolution is a function of the traditional melt-opening due to viscous heat dissipation from the water flow, and creep closure of the overlying ice, to which we add the closure or enlargement due to sediment deposition or removal, respectively. Using a simple ice geometry representing a land-terminating glacier, we find that the shear stresses produced by the water flow on the bed decrease significantly near the terminus. As the ice thins, creep closure decreases and large hydraulic potential gradients cannot be sustained. The resulting gradients in sediment transport lead to a bottleneck, and sediment accumulates if the sediment supply is adequate. A similar bottleneck occurs if a channel is well established and water discharge drops. Whether such constriction happens in space of time, in the presence of a sufficiently large sediment supply sediment accumulates temporarily near the terminus, followed shortly thereafter by enhanced sediment transport. Reduction in the cross-sectional area

  16. Dynamics of organic carbon losses by water erosion after biocrust removal

    Directory of Open Access Journals (Sweden)

    Cantón Yolanda

    2014-12-01

    Full Text Available In arid and semiarid ecosystems, plant interspaces are frequently covered by communities of cyanobacteria, algae, lichens and mosses, known as biocrusts. These crusts often act as runoff sources and are involved in soil stabilization and fertility, as they prevent erosion by water and wind, fix atmospheric C and N and contribute large amounts of C to soil. Their contribution to the C balance as photosynthetically active surfaces in arid and semiarid regions is receiving growing attention. However, very few studies have explicitly evaluated their contribution to organic carbon (OC lost from runoff and erosion, which is necessary to ascertain the role of biocrusts in the ecosystem C balance. Furthermore, biocrusts are not resilient to physical disturbances, which generally cause the loss of the biocrust and thus, an increase in runoff and erosion, dust emissions, and sediment and nutrient losses. The aim of this study was to find out the influence of biocrusts and their removal on dissolved and sediment organic carbon losses. One-hour extreme rainfall simulations (50 mm h-1 were performed on small plots set up on physical soil crusts and three types of biocrusts, representing a development gradient, and also on plots where these crusts were removed from. Runoff and erosion rates, dissolved organic carbon (DOC and organic carbon bonded to sediments (SdOC were measured during the simulated rain. Our results showed different SdOC and DOC for the different biocrusts and also that the presence of biocrusts substantially decreased total organic carbon (TOC (average 1.80±1.86 g m-2 compared to physical soil crusts (7.83±3.27 g m-2. Within biocrusts, TOC losses decreased as biocrusts developed, and erosion rates were lower. Thus, erosion drove TOC losses while no significant direct relationships were found between TOC losses and runoff. In both physical crusts and biocrusts, DOC and SdOC concentrations were higher during the first minutes after runoff

  17. Integrating Phosphorus Movement with Soil and Water Loss in the Daily Erosion Project

    Science.gov (United States)

    Sklenar, Tim; Perez-Bidegain, Mario; Cruse, Richard; Gelder, Brian; Herzmann, Daryl

    2016-04-01

    The Daily Erosion Project (DEP) is an ongoing modelling effort which is now in its second generation. DEP provides comprehensive and dynamic estimates of sediment delivery, soil erosion, and hill slope runoff for agricultural land areas across the Midwestern United States every day for Hydrologic Unit Code 12 (HUC 12) size watersheds. Results are posted every morning on the Internet at dailyerosion.org. Currently DEP covers all of Iowa and portions of Kansas and Minnesota, but expansion of coverage is ongoing. The integration of highly resolute spatial and temporal climate data, soil properties, crop rotation and residue management data affords the opportunity to test the effects of using multiple conservation practices on the transport and fate of water borne nutrients, especially phosphorus, on the Midwestern United States agricultural landscapes. Understanding the interaction of different environmental and land management practices on phosphorus movement will allow data from the DEP to guide conservation efforts as expansion continues into surrounding Midwestern states. The presentation will provide an overview of the DEP technology, including how input data are derived and used to make daily erosion estimates on over 200,000 flowpaths in the modelling area, as well as a discussion of the ongoing phosphorus transport modelling efforts and plans for future expansion (both land area and model functionality).

  18. Implications of biocrust removal on soil organic carbon losses by water erosion in a badlands area

    Science.gov (United States)

    Chamizo, Sonia; Raúl Román, José; Miralles, Isabel; Rodríguez-Caballero, Emilio; Cantón, Yolanda

    2015-04-01

    In arid and semiarid ecosystems, soils are characterized by having low organic carbon (OC) content and low fertility. In these systems, runoff, often generated in interplant soils, plays a crucial role in OC redistribution from source (interplant) areas to sink (vegetation) patches. Far from being bare, interplant soils in most arid and semiarid ecosystems are commonly covered by communities of cyanobacteria, algae, lichens and mosses, known as biocrusts, which may reach up to 80% of soil cover. Biocrusts fix atmospheric C and increase the soil OC pool by several folds respect bare soils. In addition, biocrusts form a film on the surface that strongly protects soils against water erosion and prevents from OC losses. However, the role of BSCs in reducing OC losses associated to runoff and erosion may depend on the type and development of biocrust. On the other hand, loss of BSCs provoked by frequent disturbances in arid and semiarid areas leads to an increase in runoff and erosion, which may have important effects on OC losses and nutrient impoverishment in interplant areas. Despite their recognized role, very few studies have explicitly evaluated OC losses from runoff and erosion in soils covered by different types of biocrusts and, more importantly, the effects of biocrust disturbance on OC losses. The aim of this study was to analyse the influence of two biocrust types (cyanobacteria and lichens) as well as of biocrust removal on dissolved and sediment OC losses, in a badlands site of southeastern Spain. Runoff and erosion after rain were measured in small field plots (1 m2) during one hydrological year and water samples collected for determination of dissolved OC and OC bonded to sediments. Our results showed that total OC losses decreased with biocrust development and that biocrust removal caused a dramatic increase in OC losses. The first rain after biocrust removal contributed the most to OC losses as runoff and, more noticeable, erosion greatly increased

  19. The geomorphic legacy of water and erosion control structures in a semiarid rangeland watershed

    Science.gov (United States)

    Nichols, Mary H.; Magirl, Christopher S.; Sayre, N.F.; Shaw, Jeremy R.

    2017-01-01

    Control over water supply and distribution is critical for agriculture in drylands where manipulating surface runoff often serves the dual purpose of erosion control. However, little is known of the geomorphic impacts and legacy effects of rangeland water manipulation infrastructure, especially if not maintained. This study investigated the geomorphic impacts of structures such as earthen berms, water control gates, and stock tanks, in a semiarid rangeland in the southwestern USA that is responding to both regional channel incision that was initiated over a century ago, and a more recent land use change that involved cattle removal and abandonment of structures. The functional condition of remnant structures was inventoried, mapped, and assessed using aerial imagery and lidar data. Headcut initiation, scour, and channel incision associated with compromised lateral channel berms, concrete water control structures, floodplain water spreader berms, and stock tanks were identified as threats to floodplains and associated habitat. Almost half of 27 identified lateral channel berms (48%) have been breached and 15% have experienced lateral scour; 18% of 218 shorter water spreader berms have been breached and 17% have experienced lateral scour. A relatively small number of 117 stock tanks (6%) are identified as structurally compromised based on analysis of aerial imagery, although many currently do not provide consistent water supplies. In some cases, the onset of localized disturbance is recent enough that opportunities for mitigation can be identified to alter the potentially damaging erosion trajectories that are ultimately driven by regional geomorphic instability. Understanding the effects of prior land use and remnant structures on channel and floodplain morphologic condition is critical because both current land management and future land use options are constrained by inherited land use legacy effects.

  20. A Quantitative Method for Long-Term Water Erosion Impacts on Productivity with a Lack of Field Experiments: A Case Study in Huaihe Watershed, China

    Directory of Open Access Journals (Sweden)

    Degen Lin

    2016-07-01

    Full Text Available Water erosion causes reduced farmland productivity, and with a longer period of cultivation, agricultural productivity becomes increasingly vulnerable. The vulnerability of farmland productivity needs assessment due to long-term water erosion. The key to quantitative assessment is to propose a quantitative method with water loss scenarios to calculate productivity losses due to long-term water erosion. This study uses the agricultural policy environmental extender (APEX model and the global hydrological watershed unit and selects the Huaihe River watershed as a case study to describe the methodology. An erosion-variable control method considering soil and water conservation measure scenarios was used to study the relationship between long-term erosion and productivity losses and to fit with 3D surface (to come up with three elements, which are time, the cumulative amount of water erosion and productivity losses to measure long-term water erosion. Results showed that: (1 the 3D surfaces fit significantly well; fitting by the 3D surface can more accurately reflect the impact of long-term water erosion on productivity than fitting by the 2D curve (to come up with two elements, which are water erosion and productivity losses; (2 the cumulative loss surface can reflect differences in productivity loss caused by long-term water erosion.

  1. HVOF and HVAF Coatings of Agglomerated Tungsten Carbide-Cobalt Powders for Water Droplet Erosion Application

    Science.gov (United States)

    Tarasi, F.; Mahdipoor, M. S.; Dolatabadi, A.; Medraj, M.; Moreau, C.

    2016-12-01

    Water droplet erosion (WDE) is a phenomenon caused by impingement of water droplets of several hundred microns to a few millimeters diameter at velocities of hundreds of meters per second on the edges and surfaces of the parts used in such services. The solution to this problem is sought especially for the moving compressor blades in gas turbines and those operating at the low-pressure end of steam turbines. Thermal-sprayed tungsten carbide-based coatings have been the focus of many studies and are industrially accepted for a multitude of wear and erosion resistance applications. In the present work, the microstructure, phase analysis and mechanical properties (micro-hardness and fracture toughness) of WC-Co coatings are studied in relation with their influence on the WDE resistance of such coatings. The coatings are deposited by high-velocity oxygen fuel (HVOF) and high-velocity air fuel (HVAF) processes. The agglomerated tungsten carbide-cobalt powders were in either sintered or non-sintered conditions. The WDE tests were performed using 0.4 mm water droplets at 300 m/s impact velocity. The study shows promising results for this cermet as WDE-resistant coating when the coating can reach its optimum quality using the right thermal spray process and parameters.

  2. Soil organic carbon redistribution by water erosion--the role of CO2 emissions for the carbon budget.

    Directory of Open Access Journals (Sweden)

    Xiang Wang

    Full Text Available A better process understanding of how water erosion influences the redistribution of soil organic carbon (SOC is sorely needed to unravel the role of soil erosion for the carbon (C budget from local to global scales. The main objective of this study was to determine SOC redistribution and the complete C budget of a loess soil affected by water erosion. We measured fluxes of SOC, dissolved organic C (DOC and CO2 in a pseudo-replicated rainfall-simulation experiment. We characterized different C fractions in soils and redistributed sediments using density fractionation and determined C enrichment ratios (CER in the transported sediments. Erosion, transport and subsequent deposition resulted in significantly higher CER of the sediments exported ranging between 1.3 and 4.0. In the exported sediments, C contents (mg per g soil of particulate organic C (POC, C not bound to soil minerals and mineral-associated organic C (MOC were both significantly higher than those of non-eroded soils indicating that water erosion resulted in losses of C-enriched material both in forms of POC and MOC. The averaged SOC fluxes as particles (4.7 g C m(-2 yr(-1 were 18 times larger than DOC fluxes. Cumulative emission of soil CO2 slightly decreased at the erosion zone while increased by 56% and 27% at the transport and depositional zone, respectively, in comparison to non-eroded soil. Overall, CO2 emission is the predominant form of C loss contributing to about 90.5% of total erosion-induced C losses in our 4-month experiment, which were equal to 18 g C m(-2. Nevertheless, only 1.5% of the total redistributed C was mineralized to CO2 indicating a large stabilization after deposition. Our study also underlines the importance of C losses by particles and as DOC for understanding the effects of water erosion on the C balance at the interface of terrestrial and aquatic ecosystems.

  3. Soil Organic Carbon Redistribution by Water Erosion – The Role of CO2 Emissions for the Carbon Budget

    Science.gov (United States)

    Wang, Xiang; Cammeraat, Erik L. H.; Romeijn, Paul; Kalbitz, Karsten

    2014-01-01

    A better process understanding of how water erosion influences the redistribution of soil organic carbon (SOC) is sorely needed to unravel the role of soil erosion for the carbon (C) budget from local to global scales. The main objective of this study was to determine SOC redistribution and the complete C budget of a loess soil affected by water erosion. We measured fluxes of SOC, dissolved organic C (DOC) and CO2 in a pseudo-replicated rainfall-simulation experiment. We characterized different C fractions in soils and redistributed sediments using density fractionation and determined C enrichment ratios (CER) in the transported sediments. Erosion, transport and subsequent deposition resulted in significantly higher CER of the sediments exported ranging between 1.3 and 4.0. In the exported sediments, C contents (mg per g soil) of particulate organic C (POC, C not bound to soil minerals) and mineral-associated organic C (MOC) were both significantly higher than those of non-eroded soils indicating that water erosion resulted in losses of C-enriched material both in forms of POC and MOC. The averaged SOC fluxes as particles (4.7 g C m−2 yr−1) were 18 times larger than DOC fluxes. Cumulative emission of soil CO2 slightly decreased at the erosion zone while increased by 56% and 27% at the transport and depositional zone, respectively, in comparison to non-eroded soil. Overall, CO2 emission is the predominant form of C loss contributing to about 90.5% of total erosion-induced C losses in our 4-month experiment, which were equal to 18 g C m−2. Nevertheless, only 1.5% of the total redistributed C was mineralized to CO2 indicating a large stabilization after deposition. Our study also underlines the importance of C losses by particles and as DOC for understanding the effects of water erosion on the C balance at the interface of terrestrial and aquatic ecosystems. PMID:24802350

  4. Soil organic carbon redistribution by water erosion--the role of CO2 emissions for the carbon budget.

    Science.gov (United States)

    Wang, Xiang; Cammeraat, Erik L H; Romeijn, Paul; Kalbitz, Karsten

    2014-01-01

    A better process understanding of how water erosion influences the redistribution of soil organic carbon (SOC) is sorely needed to unravel the role of soil erosion for the carbon (C) budget from local to global scales. The main objective of this study was to determine SOC redistribution and the complete C budget of a loess soil affected by water erosion. We measured fluxes of SOC, dissolved organic C (DOC) and CO2 in a pseudo-replicated rainfall-simulation experiment. We characterized different C fractions in soils and redistributed sediments using density fractionation and determined C enrichment ratios (CER) in the transported sediments. Erosion, transport and subsequent deposition resulted in significantly higher CER of the sediments exported ranging between 1.3 and 4.0. In the exported sediments, C contents (mg per g soil) of particulate organic C (POC, C not bound to soil minerals) and mineral-associated organic C (MOC) were both significantly higher than those of non-eroded soils indicating that water erosion resulted in losses of C-enriched material both in forms of POC and MOC. The averaged SOC fluxes as particles (4.7 g C m(-2) yr(-1)) were 18 times larger than DOC fluxes. Cumulative emission of soil CO2 slightly decreased at the erosion zone while increased by 56% and 27% at the transport and depositional zone, respectively, in comparison to non-eroded soil. Overall, CO2 emission is the predominant form of C loss contributing to about 90.5% of total erosion-induced C losses in our 4-month experiment, which were equal to 18 g C m(-2). Nevertheless, only 1.5% of the total redistributed C was mineralized to CO2 indicating a large stabilization after deposition. Our study also underlines the importance of C losses by particles and as DOC for understanding the effects of water erosion on the C balance at the interface of terrestrial and aquatic ecosystems.

  5. Constraints on Water Reservoir Lifetimes From Catchment-Wide 10Be Erosion Rates—A Case Study From Western Turkey

    Science.gov (United States)

    Heineke, Caroline; Hetzel, Ralf; Akal, Cüneyt; Christl, Marcus

    2017-11-01

    The functionality and retention capacity of water reservoirs is generally impaired by upstream erosion and reservoir sedimentation, making a reliable assessment of erosion indispensable to estimate reservoir lifetimes. Widely used river gauging methods may underestimate sediment yield, because they do not record rare, high-magnitude events and may underestimate bed load transport. Hence, reservoir lifetimes calculated from short-term erosion rates should be regarded as maximum values. We propose that erosion rates from cosmogenic 10Be, which commonly integrate over hundreds to thousands of years, are useful to complement short-term sediment yield estimates and should be employed to estimate minimum reservoir lifetimes. Here we present 10Be erosion rates for the drainage basins of six water reservoirs in Western Turkey, which are located in a tectonically active region with easily erodible bedrock. Our 10Be erosion rates for these catchments are high, ranging from ˜170 to ˜1,040 t/km2/yr. When linked to reservoir volumes, they yield minimum reservoir lifetimes between 25 ± 5 and 1,650 ± 360 years until complete filling, with four reservoirs having minimum lifespans of ≤110 years. In a neighboring region with more resistant bedrock and less tectonic activity, we obtain much lower catchment-wide 10Be erosion rates of ˜33 to ˜95 t/km2/yr, illustrating that differences in lithology and tectonic boundary conditions can cause substantial variations in erosion even at a spatial scale of only ˜50 km. In conclusion, we suggest that both short-term sediment yield estimates and 10Be erosion rates should be employed to predict the lifetimes of reservoirs.

  6. A probabilistic water erosion model for Mediterranean olive orchards with changing cover factor

    Science.gov (United States)

    Espejo Perez, A. J.; Giraldez Cervera, J. V.; Vanderlinden, K.

    2012-04-01

    A simple probabilistic framework is presented to describe soil and water loss in olive orchards in Mediterranean environments. The model is based on the exploration of field observations, obtained during three hydrological years (2003-2007) from a network of 1m2 microplots located in olive orchards throughout southern Spain. The objective of this experiment was to compare soil erosion under conventional tillage (CT) and a cover crop system (CC). The basis of the model is a linear relationship between soil and water loss (output) and key variables (input). The exploration of field observations suggested that the key variables were i) rainfall, which was easily described by a gamma probability density function (pdf), ii) slope, for which we adopted a uniform pdf, with values ranging from 4 to24%; and iii) cover factor. This factor could be well described using a truncated beta pdf, but due to the growing trend in the data we proposed an expression similar to a sigmoid curve. Runoff and sediment yield in both soil managements were best represented by exponential pdfs. To generalize the model we combined it with a Monte Carlo scheme to generate the inputs randomly. The model was run using the simulated input data and the relative frequencies of simulated output data were compared with the proposed pdfs for the observed data. The results showed the ability of the model to provide a probabilistic description of soil erosion. Observed and simulated data indicated that the probability to obtain higher soil losses was larger in CT as compared to CC. Therefore, conservationist soil management is essential for maintaining the productivity of olive orchards in this area. Keywords: soil management, erosion processes in olive orchard, probability density function, Monte Carlo scheme.

  7. Spatial distribution of water infiltration in erosion-affected arable soils of morainic landscapes

    Science.gov (United States)

    Hájek, Daniel; Gerke, Horst H.; Deumlich, Detlef; Dumbrovský, Miroslav

    2017-04-01

    In heterogeneous morainic soil landscapes, the effect of soil erosion and compaction on water infiltration can be highly complex while the erosion and tillage history may depend on the slope position. The aim was to evaluate compaction effects on the water infiltration of cultivated soils at contrasting landscape positions for no-till and conventionally tilled plots of the eroded landscape. Infiltration was measured using use the Guelph permeameter in two depths (20 and 40 cm) at two different locations with more-or-less eroded Luvisols. The saturated hydraulic conductivity (Kfs) was calculated from the steady infiltration rate of two pressure steps. Data from 4 locations at the arable soil of the CarboZalf-D field site Holzendorf (Uckermark) were characterized by relatively large spatial heterogeneity in top- and subsoil and without spatial trends. For the erosion plots in Müncheberg, infiltration data were obtained at 6 locations, 3 at a conventionally tilled and 3 at the neighboring no-till plot (i.e., one location each at the up-, mid-, and downslope positions). Here, the Kfs-values were always larger in the top- than in the subsoils and larger for the conventionally tilled than for the no-till plot. In contrast to expected tillage-induced subsoil compaction, the subsoil Kfs-values of the no-till plot were smaller than those of the tilled plot. The sampling time was before harvest of the Sudan grass crop in Müncheberg such that the plant root system was still intact while it was after harvest and soil tillage at the CarboZalf plots. The results suggest that the soil state at the time of infiltration measurement was more important for describing the soil hydraulic properties than the spatial distribution of compacted regions.

  8. Using a dynamic model to assess trends in land degradation by water erosion in Spanish Rangelands

    Science.gov (United States)

    Ibáñez, Javier; Francisco Lavado-Contador, Joaquín; Schnabel, Susanne; Pulido-Fernández, Manuel; Martínez Valderrama, Jaime

    2014-05-01

    This work presents a model aimed at evaluating land degradation by water erosion in dehesas and montados of the Iberian Peninsula, that constitute valuable rangelands in the area. A multidisciplinary dynamic model was built including weather, biophysical and economic variables that reflect the main causes and processes affecting sheet erosion on hillsides of the study areas. The model has two main and two derived purposes: Purpose 1: Assessing the risk of degradation that a land-use system is running. Derived purpose 1: Early warning about land-use systems that are particularly threatened by degradation. Purpose 2: Assessing the degree to which different factors would hasten degradation if they changed from the typical values they show at present. Derived purpose 2: Evaluating the role of human activities on degradation. Model variables and parameters have been calibrated for a typical open woodland rangeland (dehesa or montado) defined along 22 working units selected from 10 representative farms and distributed throughout the Spanish region of Extremadura. The model is the basis for a straightforward assessment methodology which is summarized by the three following points: i) The risk of losing a given amount of soil before a given number of years was specifically estimated as the percentage of 1000 simulations where such a loss occurs, being the simulations run under randomly-generated scenarios of rainfall amount and intensity and meat and supplemental feed market prices; ii) Statistics about the length of time that a given amount of soil takes to be lost were calculated over 1000 stochastic simulations run until year 1000, thereby ensuring that such amount of soil has been lost in all of the simulations, i.e. the total risk is 100%; iii) Exogenous factors potentially affecting degradation, mainly climatic and economic, were ranked in order of importance by means of a sensitivity analysis. Particularly remarkable in terms of model performance is the major role

  9. The fate of SOC during the processes of water erosion and subsequent deposition: a field study.

    Science.gov (United States)

    van Hemelryck, H.; Govers, G.; van Oost, K.; Merckx, R.

    2009-04-01

    Globally soils are the largest terrestrial pool of carbon (C). A relatively small increase or decrease in soil carbon content due to changes in land use or management practices could therefore result in a significant net exchange of C between the soil C reservoir and the atmosphere. As such, the geomorphic processes of water and tillage erosion have been identified to significantly impact on this large pool of soil organic carbon (SOC). Soil erosion, transport and deposition not only result in redistribution of sediments and associated carbon within a landscape, but also affect the exchange of C between the pedosphere and the atmosphere. The direction and magnitude of an erosion-induced change in the global C balance is however a topic of much debate as opposing processes interact: i) At eroding sites a net uptake of C could be the result of reduced respiration rates and continued inputs of newly produced carbon. ii) Colluvial deposition of eroded sediment and SOC leads to the burial of the original topsoil and this may constrain the decomposition of its containing SOC. iii) Eroded sediment could be transported to distal depositional environments or fluvial systems where it will either be conserved or become rapidly mineralized. iv) Increased emission of CO2 due to erosion may result from the disruptive energy of erosive forces causing the breakdown of aggregates and exposing previously protected SOC to microbial decomposition. The above-mentioned processes show a large spatial and temporal variability and assessing their impact requires an integrated modeling approach. However uncertainties about the basic processes that accompany SOC displacement are still large. This study focuses on one of these large information gaps: the fate of eroded and subsequently deposited SOC. A preceding experimental study (Van Hemelryck et al., 2008) was used to identify controlling factors (erosional intensity, changes in soil structure,…). However this experimental research

  10. Can conservation trump impacts of climate change on soil erosion? An assessment from winter wheat cropland in the Southern Great Plains of the United States

    Directory of Open Access Journals (Sweden)

    Jurgen D. Garbrecht

    2015-12-01

    Full Text Available With the need to increase crop production to meet the needs of a growing population, protecting the productivity of our soil resource is essential. However, conservationists are concerned that conservation practices that were effective in the past may no longer be effective in the future under projected climate change. In winter wheat cropland in the Southern Great Plains of the U.S., increased precipitation intensity and increased aridity associated with warmer temperatures may pose increased risks of soil erosion from vulnerable soils and landscapes. This investigation was undertaken to determine which conservation practices would be necessary and sufficient to hold annual soil erosion by water under a high greenhouse gas emission scenario at or below the present soil erosion levels. Advances in and benefits of agricultural soil and water conservation over the last century in the United States are briefly reviewed, and challenges and climate uncertainties confronting resource conservation in this century are addressed. The Water Erosion Prediction Project (WEPP computer model was used to estimate future soil erosion by water from winter wheat cropland in Central Oklahoma and for 10 projected climates and 7 alternative conservation practices. A comparison with soil erosion values under current climate conditions and conventional tillage operations showed that, on average, a switch from conventional to conservation tillage would be sufficient to offset the average increase in soil erosion by water under most projected climates. More effective conservation practices, such as conservation tillage with a summer cover crop would be required to control soil erosion associated with the most severe climate projections. It was concluded that a broad range of conservation tools are available to agriculture to offset projected future increases in soil erosion by water even under assumed worst case climate change scenarios in Central Oklahoma. The problem

  11. A Comparison of Splash Erosion Behavior between Wettable and Water Repellent 'Soil' Particles

    Science.gov (United States)

    Ahn, S.; Hamlett, C. A.; Doerr, S.; Bryant, R.; Shirtcliffe, N.; McHale, G.; Newton, M.

    2011-12-01

    Wildfires remove vegetation and litter cover and expose soil surfaces to particle detachment by rain splash. This can serve as an agent of initial soil modification and erosion in the post-fire period. Splash behavior is mainly determined by the kinetic energy delivered by impacting water drops (erosivity), and the detachability (erodibility) of surface particles, affected by their size, aggregate stability and shear strength. Soil detachability may also be affected by water repellency (hydrophobicity). This soil characteristic is influenced by wildfire and may affect splash behavior by reducing capillary forces between particles. Previous work on splash behavior using cumulative drop impact reported larger ejection droplets and lower and shorter trajectories of ejections for water repellent soil compared with wettable soil (Terry and Shakesby 1993). A water film generated by delayed infiltration on water repellent soil was suggested to account for the difference. This study compares the trajectories of ejected wettable and hydrophobic model soil particles from single water drop impacts in order to isolate the effect of soil particle wettability on splash erosion behavior. Acid-washed (wettable) and hydrophobized (water repellent) glass beads used as model soil particles were held in an array within a squat cylinder of 1.5 cm diameter in the centre of a 20 cm diameter disk covered with a viscous adhesive film. A distilled water drop (20μL) was released 40 cm above the centre of the array and the resultant impact was recorded at 976 frames per second using a high speed video camera. The populations of, and distances travelled by, the particles were measured for three arrays of bead sizes within the range (180-400 μm). Three to five replications were made for each test. The trajectory of each ejected particle was traced on video frames and corrected for the actual distance and direction of travel measured from the adhesive film. The initial velocity and ejecting

  12. Controlled erosion in asbestos-cement pipe used in drinking water distribution systems

    Directory of Open Access Journals (Sweden)

    Mariana Ramos, P.

    1990-06-01

    Full Text Available Samples of asbestos-cement pipe used for drinking water conveyance, were submerged in distilled water, and subjected to two controlled erosive treatments, namely agitation (300 rpm for 60 min and ultrasound (47 kHz for 30 min. SEM was used to observe and compare the morphology of the new pipe with and without erosive treatment, and of samples taken from asbestos-cement pipes used in the distribution system of drinking water in Santiago city for 10 and 40-years of service. TEM was used to determine the concentration of asbestos fibers in the test water: 365 MFL and 1690 MFL (millions of fibers per litre as an agitation and result ultrasound, respectively. The erosive treatments by means of agitation or ultrasound applied to new asbestos-cement pipes used in the drinking water distribution system were evaluated as being equivalent to 4 and 10 years of service, respectively.

    Se sometió a dos tratamientos erosivos controlados uno por agitación (300 rpm, 60 min. y otro por ultrasonido (47 kHz, 30 min. a muestras de tubos de asbesto cemento, sumergidas en agua destilada, usados para el trasporte de agua potable. Con SEM se observó la morfología de muestras de tubos sin uso, con y sin tratamiento erosivo y la de muestras extraídas de tubos de asbesto cemento de la red de distribución de agua potable de ía ciudad de Santiago con 10 y 14 años de servicio. Con TEM se determinó la concentración de fibras de asbesto en el agua de ensayo: 365 MFL y 1690 MFL (millones de fibras por litro en agitación y ultrasonido, respectivamente. Se estimó en 4 y 10 años de servicio equivalente los tratamientos erosivos de agitación y ultrasonido, respectivamente en tubos de asbesto cemento empleados en la red de agua potable.

  13. The influence of water erosion processes on sediment and nutriet transport from a small agricultural catchment area

    Directory of Open Access Journals (Sweden)

    František Pavlík

    2012-01-01

    Full Text Available Erosion processes in catchment areas cause serious ecologic and economic problems because of their negative consequences in terms of soil and water deterioration as well as for the environment as a whole. The soil particles washed down by water erosion are the biggest pollution factor due to their amount and volume. Sediments are the product of a selective process in which smaller and lighter particles are separated from eroded soil and taken away by water first. This means that the sediments contain a higher amount of organic, clay, and silt particles than the the original soils. Washed down sediments consist mainly of particles smaller than 0.05 mm (40–90% of the mixture. Other studies in the Czech Republic have focused on the assessment of soil erosion, based upon principles and parameters defined in the Universal Soil Loss Equation, but none of them has dealt with nutrient transport assessment as a consequence of water erosion. This paper presents a summary concerning the nutrient content in erosion sediment in a selected catchment area. Research work was conducted to identify and quantify the sediment load associated with nutrient transport especially from arable land on different soil types.

  14. Observations and Predictions of Wave Runup, Extreme Water Levels, and Medium-Term Dune Erosion during Storm Conditions

    Directory of Open Access Journals (Sweden)

    Serge Suanez

    2015-07-01

    Full Text Available Monitoring of dune erosion and accretion on the high-energy macrotidal Vougot beach in North Brittany (France over the past decade (2004–2014 has revealed significant morphological changes. Dune toe erosion/accretion records have been compared with extreme water level measurements, defined as the sum of (i astronomic tide; (ii storm surge; and (iii vertical wave runup. Runup parameterization was conducted using swash limits, beach profiles, and hydrodynamic (Hm0, Tm0,–1, and high tide water level—HTWL data sets obtained from high frequency field surveys. The aim was to quantify in-situ environmental conditions and dimensional swash parameters for the best calibration of Battjes [1] runup formula. In addition, an empirical equation based on observed tidal water level and offshore wave height was produced to estimate extreme water levels over the whole period of dune morphological change monitoring. A good correlation between this empirical equation (1.01Hmoξo and field runup measurements (Rmax was obtained (R2 85%. The goodness of fit given by the RMSE was about 0.29 m. A good relationship was noticed between dune erosion and high water levels when the water levels exceeded the dune foot elevation. In contrast, when extreme water levels were below the height of the toe of the dune sediment budget increased, inducing foredune recovery. These erosion and accretion phases may be related to the North Atlantic Oscillation Index.

  15. Rain erosion of wind turbine blade coatings using discrete water jets: Effects of water cushioning, substrate geometry, impact distance, and coating properties

    DEFF Research Database (Denmark)

    Zhang, Shizhong; Dam-Johansen, Kim; Bernad, Pablo L.

    2015-01-01

    Rapid and reliable rain erosion screening of blade coatings for wind turbines is a strong need in the coatings industry. One possibility in this direction is the use of discrete water jets, where so-called jet slugs are impacted on a coating surface. Previous investigations have mapped......, confirm the conclusion from the previous investigation that a direct correlation of data from discrete water jet experiments with those obtained in the whirling arm rig does not seem possible (at least not for the blade coatings considered). The underlying mechanisms of rain erosion are substantially...... the influence of water jet slug velocity and impact frequency. In the present work, the effects on coating erosion of water cushioning, substrate curvature, and water nozzle-coating distance were explored. The investigations showed that in some cases water cushioning (the presence of a liquid film...

  16. Numerical simulation study on erosion mechanism of pre-mixed abrasive water jet

    National Research Council Canada - National Science Library

    Meng, Junqing; Wei, Qingen; Ma, Yechao

    2017-01-01

    ... to simulate single abrasive particle of rock erosion rule and analyze the influence of different particle size, different grinding particle impact velocity, different abrasive particle shape on rock erosion effect...

  17. Evaluating water erosion prediction project model using Cesium-137-derived spatial soil redistribution data

    Science.gov (United States)

    The lack of spatial soil erosion data has been a major constraint on the refinement and application of physically based erosion models. Spatially distributed models can only be thoroughly validated with distributed erosion data. The fallout cesium-137 has been widely used to generate spatial soil re...

  18. Facing the scaling problem: A multi-methodical approach to simulate soil erosion at hillslope and catchment scale

    Science.gov (United States)

    Schmengler, A. C.; Vlek, P. L. G.

    2012-04-01

    Modelling soil erosion requires a holistic understanding of the sediment dynamics in a complex environment. As most erosion models are scale-dependent and their parameterization is spatially limited, their application often requires special care, particularly in data-scarce environments. This study presents a hierarchical approach to overcome the limitations of a single model by using various quantitative methods and soil erosion models to cope with the issues of scale. At hillslope scale, the physically-based Water Erosion Prediction Project (WEPP)-model is used to simulate soil loss and deposition processes. Model simulations of soil loss vary between 5 to 50 t ha-1 yr-1 dependent on the spatial location on the hillslope and have only limited correspondence with the results of the 137Cs technique. These differences in absolute soil loss values could be either due to internal shortcomings of each approach or to external scale-related uncertainties. Pedo-geomorphological soil investigations along a catena confirm that estimations by the 137Cs technique are more appropriate in reflecting both the spatial extent and magnitude of soil erosion at hillslope scale. In order to account for sediment dynamics at a larger scale, the spatially-distributed WaTEM/SEDEM model is used to simulate soil erosion at catchment scale and to predict sediment delivery rates into a small water reservoir. Predicted sediment yield rates are compared with results gained from a bathymetric survey and sediment core analysis. Results show that specific sediment rates of 0.6 t ha-1 yr-1 by the model are in close agreement with observed sediment yield calculated from stratigraphical changes and downcore variations in 137Cs concentrations. Sediment erosion rates averaged over the entire catchment of 1 to 2 t ha-1 yr-1 are significantly lower than results obtained at hillslope scale confirming an inverse correlation between the magnitude of erosion rates and the spatial scale of the model. The

  19. RUNOFF AND EROSION IN DIFFERENT (AGRO CLIMATOLOGICAL ZONES OF LATIN AMERICA AND PROPOSALS FOR SOIL AND WATER CONSERVATION SCENARIOS

    Directory of Open Access Journals (Sweden)

    Donald Gabriels

    2005-05-01

    Full Text Available Steeplands, when cleared from forests, are susceptible to erosion by rainfall and are prone toland degradation and desertification processes.The dominant factors affecting those erosion processes and hence the resulting runoff and soillosses are the aggressiveness of the rainfall during the successive plant growth stages, the soilcover-management, but also the topography (slope length and slope steepness. Depending onthe type of (agro climatological zone, the runoff water should either be limited and controlled(excess of water or should be enhanced and collected from the slope on the downslopecropping area if water is short (negative soil water balance.Examples are given of practical applications in Ecuador where alternative soil conservationscenarios are proposed in maize cultivation in small fields on steep slopes. Adding peas andbarley in the rotation of maize and beans resulted only in a slight decrease of the soil losses.Subdividing the fields into smaller parcels proved to give the best reduction in soil loss.Because the average slope steepness is high, erosion control measures such as contourploughing and strip cropping have only small effects.Erosion and its effect on productivity of a sorghum -livestock farming system are assessed onfour different areas in Venezuela with different levels of erosion. A Productivity Index (PIand an Erosion Risk Index (ERI were used to classify the lands for soil conservationpriorities and for alternative land uses. Intensive agriculture can be applied on slightly erodedsoil, whereas severely eroded soil can be used with special crops or agro-forestry. Semiintensiveagriculture is possible on moderately eroded soil.Reforestation of drylands in Chili requires understanding of the infiltration/runoff process inorder to determine dimensions of water harvesting systems. Infiltration processes in semi-aridregions of Chile were evaluated, using rainfall experiments and constant-head infiltrationmeasurements

  20. Soil Organic Carbon Fractions and Stocks Respond to Restoration Measures in Degraded Lands by Water Erosion.

    Science.gov (United States)

    Nie, Xiaodong; Li, Zhongwu; Huang, Jinquan; Huang, Bin; Xiao, Haibing; Zeng, Guangming

    2017-05-01

    Assessing the degree to which degraded soils can be recovered is essential for evaluating the effects of adopted restoration measures. The objective of this study was to determine the restoration of soil organic carbon under the impact of terracing and reforestation. A small watershed with four typical restored plots (terracing and reforestation (four different local plants)) and two reference plots (slope land with natural forest (carbon-depleted) and abandoned depositional land (carbon-enriched)) in subtropical China was studied. The results showed that soil organic carbon, dissolved organic carbon and microbial biomass carbon concentrations in the surface soil (10 cm) of restored lands were close to that in abandoned depositional land and higher than that in natural forest land. There was no significant difference in soil organic carbon content among different topographic positions of the restored lands. Furthermore, the soil organic carbon stocks in the upper 60 cm soils of restored lands, which were varied between 50.08 and 62.21 Mg C ha -1 , were higher than 45.90 Mg C ha -1 in natural forest land. Our results indicated that the terracing and reforestation could greatly increase carbon sequestration and accumulation and decrease carbon loss induced by water erosion. And the combination measures can accelerate the restoration of degraded soils when compared to natural forest only. Forest species almost have no impact on the total amount of soil organic carbon during restoration processes, but can significantly influence the activity and stability of soil organic carbon. Combination measures which can provide suitable topography and continuous soil organic carbon supply could be considered in treating degraded soils caused by water erosion.

  1. Soil Organic Carbon Fractions and Stocks Respond to Restoration Measures in Degraded Lands by Water Erosion

    Science.gov (United States)

    Nie, Xiaodong; Li, Zhongwu; Huang, Jinquan; Huang, Bin; Xiao, Haibing; Zeng, Guangming

    2017-05-01

    Assessing the degree to which degraded soils can be recovered is essential for evaluating the effects of adopted restoration measures. The objective of this study was to determine the restoration of soil organic carbon under the impact of terracing and reforestation. A small watershed with four typical restored plots (terracing and reforestation (four different local plants)) and two reference plots (slope land with natural forest (carbon-depleted) and abandoned depositional land (carbon-enriched)) in subtropical China was studied. The results showed that soil organic carbon, dissolved organic carbon and microbial biomass carbon concentrations in the surface soil (10 cm) of restored lands were close to that in abandoned depositional land and higher than that in natural forest land. There was no significant difference in soil organic carbon content among different topographic positions of the restored lands. Furthermore, the soil organic carbon stocks in the upper 60 cm soils of restored lands, which were varied between 50.08 and 62.21 Mg C ha-1, were higher than 45.90 Mg C ha-1 in natural forest land. Our results indicated that the terracing and reforestation could greatly increase carbon sequestration and accumulation and decrease carbon loss induced by water erosion. And the combination measures can accelerate the restoration of degraded soils when compared to natural forest only. Forest species almost have no impact on the total amount of soil organic carbon during restoration processes, but can significantly influence the activity and stability of soil organic carbon. Combination measures which can provide suitable topography and continuous soil organic carbon supply could be considered in treating degraded soils caused by water erosion.

  2. Spatially-varied erosion modeling using WEPP for timber harvested and burned hillslopes

    Science.gov (United States)

    Peter R. Robichaud; T. M. Monroe

    1997-01-01

    Spatially-varied hydrologic surface conditions exist on steep hillslopes after timber harvest operation and site preparation burning treatments. Site preparation burning creates low- and high-severity burn surface conditions or disturbances. In this study, a hillslope was divided into multiple combinations of surface conditions to determine how their spatial...

  3. Soil tillage, water erosion, and calcium, magnesium and organic carbon losses

    Directory of Open Access Journals (Sweden)

    Bertol Ildegardis

    2005-01-01

    Full Text Available Soil tillage influences water erosion, and consequently, losses of calcium, magnesium and organic carbon in surface runoff. Nutrients and organic carbon are transported by surface runoff in particulate form, adsorbed to soil colloids or soluble in water, depending on the soil tillage system. This study was carried out on an Inceptisol, representative of the Santa Catarina highlands, southern Brazil, between November 1999 and October 2001, under natural rainfall. The soil tillage treatments (no replications were: no-tillage (NT, minimum soil tillage with chiseling + disking (MT, and conventional soil tillage with plowing + two diskings (CT. The crop cycles sequence was soybean (Glycine max, oats (Avena sativa, beans (Phaseolus vulgaris and vetch (Vicia sativa. Conventional soil tillage treatment with plowing + two disking in the absence of crops (BS was also studied. Calcium and magnesium concentrations were determined in both water and sediments of the surface runoff, while organic carbon was measured only in sediments. Calcium and magnesium concentrations were greater in sediments than in surface runoff, while total losses of these elements were greater in surface runoff than in sediments. The greatest calcium and magnesium concentrations in surface runoff were obtained under CT, while in sediments the greatest concentration occurred under MT. Organic carbon concentration in sediments did not differ under the different soil tillage systems, and the greatest total loss was under CT system.

  4. Water Erosion in Relation with Soil Management System and Crop Sequence during 20 Years on an Inceptisol in South Brazil

    Science.gov (United States)

    Bertol, I.; Schick, J.; Barbosa, F. T.; Paz-Ferreiro, J.; Flores, M. T.; Paz González, A.

    2012-04-01

    Soil erosion still remains persistent at the world scale, even if big efforts have been done to control and reduce it, mainly using soil crop residues to protect soil surface. Although in South Brazil the main management system for most crops is no tillage and direct drilling, water erosion prevails as the most important soil erosion type, which is due both, to the high erosivity and the evenly distribution of rainfall over the year. Moreover, some crops are still grown under soil tillage systems consisting of ploughing, harrowing and less frequently chiselling. Starting 1992, a field experiment under natural rainfall has been conducted on an Inceptisol located in Lages, Santa Catarina State, Brazil, which objective was to assess rainfall water erosion. Two soil cover conditions and four soil management systems were studied: I) a crop rotation, which included oats (Avena strigosa), soybean (Glycine max), common vetch (Vicia sativa), maize (Zea mays), fodder radish (Raphanus sativus) and common bean (Phaseolus vulgaris) under the following soil management types: 1) ploughing plus two levelling operations (CT), chiselling plus levelling (RT) and direct drilling with no tillage (NT), and II) bare soil (BS) without crop cover tilled by ploughing plus two levelling. In more than 90% of the study cases, soil losses were collected for single rain events with erosive power, whose erosivity was calculated. Total rain recorded during the 20 year experimental period was approximately 66,400 mm, which is equivalent to roughly 105,700, MJ mm ha-1 h-1 (EI30), whereas soil losses in the BS treatment were higher than 1,700 t.ha-1. On average, soil losses under RT treatment showed a 92% reduction in relation with BS, whereas under CT the reduction in relation to BS was about 66%. Soil management by direct drilling (NT) was the most efficient system to minimize water erosion, as soil losses decreased about 98% when compared with BS. Moreover, soil management systems with a crop

  5. Influence of water air content on cavitation erosion in distilled water

    CSIR Research Space (South Africa)

    Auret, JG

    1993-12-01

    Full Text Available The influence of increased air content of the cavitating liquid (distilled water) was studied in a rotating disk test rig. A rise in the total air content including dissolved and entrained air of the water in the under saturated range resulted...

  6. Modelling water erosion in the Sahel: application of a physically based soil erosion model in a gentle sloping environment

    NARCIS (Netherlands)

    Visser, S.M.; Sterk, G.; Karssenberg, D.

    2005-01-01

    Water is a major limiting factor in arid and semi-arid agriculture. In the Sahelian zone of Africa, it is not always the limited amount of annual rainfall that constrains crop production, but rather the proportion of rainfall that enters the root zone and becomes plant-available soil moisture.

  7. Effects of tannin-fluoride and milk-fluoride mixture on human enamel erosion from inappropriately chlorinated pool water.

    Science.gov (United States)

    Boonviriya, Sumalee; Tannukit, Sissada; Jitpukdeebodintra, Suwanna

    2017-01-01

    This in vitro study aimed to investigate the efficacy of tannin-fluoride and milk-fluoride mixtures on human enamel erosion after exposure to inappropriately chlorinated pool water. Enamel specimens were immersed in swimming pool water (pH 2.7) for 30 min and in each test reagent for 4 min once a day for 60 consecutive days (group I: control, group II: tannin-fluoride, group III: milk-fluoride, group IV: tannin-fluoride before and milk-fluoride after erosive challenge, and group V: milk containing tannin-fluoride before and after erosive exposure). Surface microhardness was assessed on days 0, 30, and 60. Scanning electron microscopy (SEM) and electron probe microanalysis (EPMA) were performed after treatment of samples for 60 days. Surface microhardness of experimental groups was ranked as follows: group III > group IV-group V > group II > group I (P EPMA profiles showed decrease of phosphorus and increase of fluoride content in groups II and IV. In conclusion, we demonstrated that treatment with fluoridated milk with or without tannin-fluoride has protective effects against enamel erosion caused by low-pH swimming pool water.

  8. Barrier erosion control test plan: Gravel mulch, vegetation, and soil water interactions

    Energy Technology Data Exchange (ETDEWEB)

    Waugh, W.J.; Link, S.O. (Pacific Northwest Lab., Richland, WA (USA))

    1988-07-01

    Soil erosion could reduce the water storage capacity of barriers that have been proposed for the disposal of near-surface waste at the US Department of Energy's Hanford Site. Gravel mixed into the top soil surface may create a self-healing veneer that greatly retards soil loss. However, gravel admixtures may also enhance infiltration of rainwater, suppress plant growth and water extraction, and lead to the leaching of underlying waste. This report describes plans for two experiments that were designed to test hypotheses concerning the interactive effects of surface gravel admixtures, revegetation, and enhanced precipitation on soil water balance and plant abundance. The first experiment is a factorial field plot set up on the site selected as a soil borrow area for the eventual construction of barriers. The treatments, arranged in a a split-split-plot design structure, include two densities of gravel admix, a mixture of native and introduced grasses, and irrigation to simulate a wetter climate. Changes in soil water storage and plant cover are monitored with neutron moisture probes and point intercept sampling, respectively. The second experiment consists of an array of 80 lysimeters containing several different barrier prototypes. Surface treatments are similar to the field-plot experiment. Drainage is collected from a valve at the base of each lysimeter tube, and evapotranspiration is estimated by subtraction. The lysimeters are also designed to be coupled to a whole-plant gas exchange system that will be used to conduct controlled experiments on evapotranspiration for modeling purposes. 56 refs., 6 figs., 8 tabs.

  9. Vegetation cover, avoided erosion and water quality in high Andean wetlands, Yeso River Basin

    Science.gov (United States)

    León, Alejandro; Soto, Jorge; Seguel, Oscar; Pérez, Javier; Osses, Daniela; Leiva, Nicolás; Zerega, Linka

    2017-04-01

    Wetlands on the high Andes mountains near Santiago de Chile have been impacted by overgrazing and off-road tourists. We studied wetlands in El Yeso River basin. In February 2015 we established 36 exclusions and measured vegetation cover and height, biomass production in and out the exclusions starting in October. Water and undisturbed soil samples were collected. Data were analyzed statistically to estimate i) the recovery of vegetation, and ii) the influence of grazing and vehicle traffic on vegetation loss, and iii) impacts on soil and water quality. In areas with less intense traffic, the difference in vegetation coverage in and out the exclusions is 22% (± 11.4%); in areas with more intense traffic this difference is 16% (± 16%). Height of vegetation, in the less intense traffic areas, ranges from 6.25 cm (± 2.8) to 13.32 cm (± 6.3). With higher traffic it varies between 6.9 cm (± 3.1) and 13.6 cm (± 5.4). Biomass varies between 0.06 kg DM/m2 to 0.57 kg DM/m2 depending on botanical composition and date. After water circulates through the wetlands its content of nitrogen increases 37.33% to 0.37 mg N/l and the fecal coliforms 66.67% to 0.67 MPN/100 ml, because of cattle. On the contrary, turbidity decreases 20.67% to 0.21 UNT because sediments are captured by vegetation. We also estimated an avoided erosion rate, ranging between 1.23% and 31.87% (depending on the slope) due to the increase in coverage within the exclusions.

  10. Application of experimental soil erosion models (USLE, RUSLE) in Jordan: A review

    Science.gov (United States)

    Ramzi, A. A.; Ayu, A. W.; Mohm, A. A.; Fahmi, R. M.; Ibrahim, O. M.

    2017-09-01

    required to be utilised essentially as screening devices in coordinated reviews, arrive asset appraisals would request expanded precision in the measurement of disintegration rates in a spatial and fleeting setting. On the off chance, the necessities can be propose, for instance the Water Erosion Prediction Project (WEPP) can be required to discover expanded application in delivering quantitative appraisals of soil erosion and residue yield in Jordan.

  11. Managing erosion, sediment transport and water quality in drained peatland catchments

    OpenAIRE

    Marttila, H. (Hannu)

    2011-01-01

    Abstract Peatland drainage changes catchment conditions and increases the transport of suspended solids (SS) and nutrients. New knowledge and management methods are needed to reduce SS loading from these areas. This thesis examines sediment delivery and erosion processes in a number of peatland drainage areas and catchments in order to determine the effects of drainage on sediment and erosion dynamics and mechanics. Results from studies performed in peat mining, peatland forestry and distu...

  12. Muddied Waters: Estimating the national economic cost of soil erosion and sedimentation in New Zealand

    OpenAIRE

    Eastwood, Callum; Krausse, Michael; Alexander, Robert R

    2000-01-01

    Soil erosion research in New Zealand has focused on the on-site costs of soil loss in the form of production loss and storm damage. Subsidization and implementation of soil conservation measures have primarily been justified through maintenance or improvement of farm productivity levels. The shift in responsibility for soil conservation management and damage remedies from national to regional government has highlighted public good issues raised by soil erosion. This paper develops an inventor...

  13. Effects of Long-term Conservation Tillage on Soil Nutrients in Sloping Fields in Regions Characterized by Water and Wind Erosion

    OpenAIRE

    Chunjian Tan; Xue Cao; Shuai Yuan; Weiyu Wang; Yongzhong Feng; Bo Qiao

    2015-01-01

    Conservation tillage is commonly used in regions affected by water and wind erosion. To understand the effects of conservation tillage on soil nutrients and yield, a long-term experiment was set up in a region affected by water and wind erosion on the Loess Plateau. The treatments used were traditional tillage (CK), no tillage (NT), straw mulching (SM), plastic-film mulching (PM), ridging and plastic-film mulching (RPM) and intercropping (In). Our results demonstrate that the available nutrie...

  14. Bank Erosion, Mass Wasting, Water Clarity, Bathymetry and a Sediment Budget Along the Dam-Regulated Lower Roanoke River, North Carolina

    Science.gov (United States)

    Schenk, Edward R.; Hupp, Cliff R.; Richter, Jean M.; Kroes, Daniel E.

    2010-01-01

    Dam construction and its impact on downstream fluvial processes may substantially alter ambient bank stability, floodplain inundation patterns, and channel morphology. Most of the world's largest rivers have been dammed, which has prompted management efforts to mitigate dam effects. Three high dams (completed between 1953 and 1963) occur along the Piedmont portion of the Roanoke River, North Carolina; just downstream, the lower part of the river flows across largely unconsolidated Coastal Plain deposits. To document bank erosion rates along the lower Roanoke River, more than 700 bank erosion pins were installed along 124 bank transects. Additionally, discrete measurements of channel bathymetry, water clarity, and presence or absence of mass wasting were documented along the entire 153-kilometer-long study reach. Amounts of bank erosion in combination with prior estimates of floodplain deposition were used to develop a bank erosion and floodplain deposition sediment budget for the lower river. Present bank erosion rates are relatively high [mean 42 milimeters per year (mm/yr)] and are greatest along the middle reaches (mean 60 mm/yr) and on lower parts of the bank on all reaches. Erosion rates were likely higher along upstream reaches than present erosion rates such that erosion rate maxima have migrated downstream. Mass wasting and water clarity also peak along the middle reaches.

  15. Characteristics of Soil and Organic Carbon Loss Induced by Water Erosion on the Loess Plateau in China.

    Science.gov (United States)

    Li, Zhongwu; Nie, Xiaodong; Chang, Xiaofeng; Liu, Lin; Sun, Liying

    2016-01-01

    Soil erosion has been a common environmental problem in the Loess Plateau in China. This study aims to better understand the losses of soil organic carbon (SOC) induced by water erosion. Laboratory-simulated rainfall experiments were conducted to investigate the characteristics of SOC loss induced by water erosion. The applied treatments included two rainfall intensities (90 and 120 mm h-1), four slope gradients (10°, 15°, 20°, and 25°), and two typical soil types- silty clay loam and silty loam. Results showed that the sediment OC enrichment ratios (ERoc) in all the events were relative stable with values ranged from 0.85 to1.21 and 0.64 to 1.52 and mean values of 0.98 and 1.01 for silty clay loam and silty loam, respectively. Similar to the ERoc, the proportions of different sized particles in sediment showed tiny variations during erosion processes. No significant correlation was observed between ERoc values and the proportions of sediment particles. Slope, rainfall intensity and soil type almost had no impact on ERoc. These results indicate that the transportation of SOC during erosion processes was nonselective. While the mean SOC loss rates for the events of silty clay loam and silty loam were 0.30 and 0.08 g m-2 min-1, respectively. Greater differences in SOC loss rates were found in events among different soil types. Meanwhile, significant correlations between SOC loss and soil loss for all the events were observed. These results indicated that the amount of SOC loss was influenced primarily by soil loss and the SOC content of the original soil. Erosion pattern and original SOC content are two main factors by which different soils can influence SOC loss. It seems that soil type has a greater impact on SOC loss than rainfall characteristics on the Loess Plateau of China. However, more kinds of soils should be further studied due to the special formation processes in the Loess Plateau.

  16. Estimating the impact of seawater on the production of soil water-extractable organic carbon during coastal erosion.

    Science.gov (United States)

    Dou, Fugen; Ping, Chien-Lu; Guo, Laodong; Jorgenson, Torre

    2008-01-01

    The production of water-extractable organic carbon (WEOC) during arctic coastal erosion and permafrost degradation may contribute significantly to C fluxes under warming conditions, but it remains difficult to quantify. A tundra soil collected near Barrow, AK, was selected to evaluate the effects of soil pretreatments (oven drying vs. freeze drying) as well as extraction solutions (pure water vs. seawater) on WEOC yields. Both oven drying and freeze drying significantly increased WEOC release compared with the original moist soil samples; dried samples released, on average, 18% more WEOC than did original moist samples. Similar results were observed for the production of low-molecular-weight dissolved organic C. However, extractable OC released from different soil horizons exhibited differences in specific UV absorption, suggesting differences in WEOC quality. Furthermore, extractable OC yields were significantly less in samples extracted with seawater compared with those extracted with pure water, likely due to the effects of major ions on extractable OC flocculation. Compared with samples from the active horizons, upper permafrost samples released more WEOC, suggesting that continuously frozen samples were more sensitive than samples that had experienced more drying-wetting cycles in nature. Specific UV absorption of seawater-extracted OC was significantly lower than that of OC extracted using pure water, suggesting more aromatic or humic substances were flocculated during seawater extraction. Our results suggest that overestimation of total terrestrial WEOC input to the Arctic Ocean during coastal erosion could occur if estimations were based on WEOC extracted from dried soil samples using pure water.

  17. Water erosion during a 17-year period under two crop rotations in four soil management systems on a Southbrazilian Inceptisol

    Science.gov (United States)

    Bertol, Ildegardis; Vidal Vázquez, Eva; Paz Ferreiro, Jorge

    2010-05-01

    Soil erosion still remains a persistent issue in the world, and this in spite of the efforts to ameliorate soil management systems taken into account the point of view of environmental protection against soil losses. In South Brazil water erosion is mainly associated to rainfall events with a great volume and high intensity, which are more or less evenly distributed all over the year. Nowadays, direct drilling is the most widely soil management system used for the main crops of the region. However, some crops still are grown on conventionally tilled soils, which means mainly ploughing and harrowing and less frequently chisel ploughing. In Lages-Santa Catarina State, Brazil, a plot experiment under natural rain was started in 1992 on an Inceptisol with the aim of quantifying soil and water losses. Treatments included bare and vegetated plots. The crop succession was: oats (Avena strigosa), soybean (Glycine max), vetch (Vicia sativa), maize (Zea mays), fodder radish (Raphanus sativus) and beans (Phaseolus vulgaris). Soil tillage systems investigated in this study were: i) conventional tillage (CT), ii) reduced tillage (MT), iii) no tillage (NT) under crop rotation and iv) conventional tillage on bare soil (BS). Treatments CT and BS involved ploughing plus twice harrowing, whereas MT involved chisel ploughing plus harrowing. Rainfall erosivity from January 1 1992 to December 31 2009 was calculated. Soil losses from the BS treatment along the 17 year study period were higher than 1200 Mg ha-1. Crop cover significantly reduced erosion, so that under some crops soil losses in the CT treatment were 80% lower than in the BS treatment. In turn soil losses in the MT treatment, where tillage was performed by chiselling and harrowing, were on average about 50% lower than in the CT treatment. No tillage was the most efficient soil management system in reducing soil erosion, so that soil losses in the NT treatment were about 98% lower than in the BS treatment. The three

  18. Rill erosion rates in burned forests

    Science.gov (United States)

    Joseph W. Wagenbrenner; Peter R. Robichaud

    2011-01-01

    Introduction Wildfires often produce large increases in runoff and erosion rates (e.g., Moody and Martin, 2009), and land managers need to predict the frequency and magnitude of postfire erosion to determine the needs for hazard response and possible erosion mitigation to reduce the impacts of increased erosion on public safety and valued resources. The Water Erosion...

  19. Effects of soil management techniques on soil water erosion in apricot orchards

    NARCIS (Netherlands)

    Keesstra, Saskia; Pereira, Paulo; Novara, Agata; Brevik, Eric C.; Azorin-Molina, Cesar; Parras-Alcántara, Luis; Jordán, Antonio; Cerdà, Artemi

    2016-01-01

    Soil erosion is extreme in Mediterranean orchards due to management impact, high rainfall intensities, steep slopes and erodible parent material. Vall d'Albaida is a traditional fruit production area which, due to the Mediterranean climate and marly soils, produces sweet fruits. However, these

  20. Chuvas intensas relacionadas à erosão hídrica Intense rainfalls related to water erosion

    Directory of Open Access Journals (Sweden)

    Glenio G. Santos

    2010-02-01

    Full Text Available As características das precipitações que mais interferem no processo de erosão do solo são a intensidade, a duração e a frequência da precipitação e a sua erosividade. Sendo o solo um recurso de renovação lenta e podendo ser rapidamente degradado pela ação da erosão, torna-se fundamental o conhecimento da forma como a precipitação atua no ambiente no qual esteja inserido. Desta forma se facilitam o desenvolvimento de técnicas e tecnologias e o estabelecimento de ações para diagnosticar, avaliar e apresentar soluções aos problemas, tanto econômica como ambientalmente. Diversos trabalhos, incluindo resultados de pesquisas e desenvolvimento de modelos, têm correlacionado as características das precipitações no sentido de entender, prever e apresentar soluções ao problema erosivo. Neste sentido se buscou compilar alguns desses trabalhos, de modo a apresentar o "estado da arte" no que se refere a chuvas intensas, manejo do solo e erosão hídrica.The most important rainfall characteristics on erosion process are the relationship between intensity, duration and frequency of precipitation and its erosivity. As the soil is a slow renewal resource and can be quickly degraded by erosion, the knowledge about how the precipitation acts in the environment is fundamental. In this way, the development of techniques, technologies and the establishment of actions to diagnose, to evaluate and to present solutions to erosion problems is important both economically and environmentally. Many studies, including research results and development of models have correlated precipitations characteristics in order to understand, to predict and to present solutions for the erosion problem. In this sense, some of these studies were compiled with the purpose of presenting the "state of the art" with respect to precipitations, soil management and water erosion.

  1. Erosion processes by water in agricultural landscapes: a low-cost methodology for post-event analyses

    Science.gov (United States)

    Prosdocimi, Massimo; Calligaro, Simone; Sofia, Giulia; Tarolli, Paolo

    2015-04-01

    Throughout the world, agricultural landscapes assume a great importance, especially for supplying food and a livelihood. Among the land degradation phenomena, erosion processes caused by water are those that may most affect the benefits provided by agricultural lands and endanger people who work and live there. In particular, erosion processes that affect the banks of agricultural channels may cause the bank failure and represent, in this way, a severe threat to floodplain inhabitants and agricultural crops. Similarly, rills and gullies are critical soil erosion processes as well, because they bear upon the productivity of a farm and represent a cost that growers have to deal with. To estimate quantitatively soil losses due to bank erosion and rills processes, area based measurements of surface changes are necessary but, sometimes, they may be difficult to realize. In fact, surface changes due to short-term events have to be represented with fine resolution and their monitoring may entail too much money and time. The main objective of this work is to show the effectiveness of a user-friendly and low-cost technique that may even rely on smart-phones, for the post-event analyses of i) bank erosion affecting agricultural channels, and ii) rill processes occurring on an agricultural plot. Two case studies were selected and located in the Veneto floodplain (northeast Italy) and Marche countryside (central Italy), respectively. The work is based on high-resolution topographic data obtained by the emerging, low-cost photogrammetric method named Structure-from-Motion (SfM). Extensive photosets of the case studies were obtained using both standalone reflex digital cameras and smart-phone built-in cameras. Digital Terrain Models (DTMs) derived from SfM revealed to be effective to estimate quantitatively erosion volumes and, in the case of the bank eroded, deposited materials as well. SfM applied to pictures taken by smartphones is useful for the analysis of the topography

  2. Modelling tillage and water erosion by using WATEM/SEDEM and 137Cs measurements at field scale

    Science.gov (United States)

    Quijano, Laura; Beguería, Santiago; Gaspar, Leticia; Navas, Ana

    2016-04-01

    The estimation of soil redistribution rates is necessary to evaluate the environmental impact of soil erosion including the loss of fertile topsoil which is one of the main soil degradation problems in agricultural landscapes. Modelling approach offers a potential tool for quantifying soil redistribution and to propose site-specific control measures to minimize soil degradation in agroecosystems. Studies at field scale using spatially distributed data of 137Cs derived soil redistribution rates to calibrate and evaluate the uncertainties of distributed models are required but are still scarcely implemented. This study applies the WATEM/SEDEM model to estimate soil redistribution rates after calibration with 137Cs measurements. Furthermore, soil redistribution rates by tillage were estimated using the Mass Balance Model 3 (MBM3). A representative Mediterranean cultivated field located in the central part of the Ebro basin (NE Spain) was selected to conduct the study. A digital elevation model (DEM) at high resolution (2.5 m) of the study field was generated to characterize the land surface. The elevation of a total of 617 points was measured on a 5 m grid using a total topographic station and 156 bulk soil samples were collected on a 10 m grid for soil analysis. According to field observations and topographical surveys four hydrological units were identified within the study field characterized by different hydrological behavior. The results indicated that soil erosion predominated over soil deposition. Mean values of 137Cs derived soil erosion and deposition rates were 19.7 Mg ha-1 yr-1 and 12.6 Mg ha-1 yr-1, respectively. The rates obtained with WATEM/SEDEM model were lower; mean erosion was 3.9 Mg ha-1 yr-1 and mean deposition rates that occurred in 35% of the grid cells was 5.8 Mg ha-1 yr-1. Water erosion was the major factor controlling soil redistribution whereas tillage erosion was almost negligible. These results are in line with the tillage rates obtained

  3. Study Regarding the Good Cavitation Erosion Resistance of a 13Cr-4Ni Stainless Steel used to Manufacture the Components Exposed to Water of the Hydraulic Turbines

    Directory of Open Access Journals (Sweden)

    Marian-Dumitru Nedeloni

    2017-11-01

    Full Text Available This paper presents some information regarding the hydraulic turbines respectively the experimental results on cavitation erosion behavior of a 13Cr-4Ni stainless steel used to manufacture the components exposed to water of the Francis, Kaplan and Pelton hydraulic turbines. So, the presented experimental results of this paper highlight the good cavitation erosion resistance of the analyzed 13Cr-4Ni stainless steel.

  4. Spatial and temporal heterogeneity of water soil erosion in a Mediterranean rain-fed crop

    Science.gov (United States)

    López-Vicente, M.; Quijano, L.; Gaspar, L.; Machín, J.; Navas, A.

    2012-04-01

    Fertile soil loss by raindrop impact and runoff processes in croplands presents significant variations at temporal and spatial scales. The combined use of advanced GIS techniques and detailed databases allows high resolution mapping of runoff and soil erosion processes. In this study the monthly values of soil loss are calculated in a medium size field of rain-fed winter barley and its drainage area located in the Central Spanish Pre-Pyrenees. The field is surrounded by narrow strips of dense Mediterranean vegetation (mainly holm oaks) and grass. Man-made infrastructures (paved trails and drainage ditches) modify the overland flow pathways and the study site appears hydrologically closed in its northern and western boundaries. This area has a continental Mediterranean climate with two humid periods, one in spring and a second in autumn and a dry summer with rainfall events of high intensity from July to October. The average annual rainfall is 495 mm and the average monthly rainfall intensity ranges from 1.1 mm / h in January to 7.4 mm / h in July. The predicted rates were obtained after running the RMMF model (Morgan, 2001) with the enhancements made to this model by Morgan and Duzant (2008) to the topographic module, and by López-Vicente and Navas (2010) to the hydrological module. A total of 613 soil samples were collected and all input and output maps were generated at high spatial resolution (1 x 1 m of cell size) with ArcMapTM 10.0. A map of effective cumulative runoff was calculated for each month of the year with a weighted multiple flow algorithm and four sub-catchments were distinguished within the field. The average soil erosion in the cultivated area is 1.32 Mg / ha yr and the corresponding map shows a high spatial variability (s.d. = 7.52 Mg / ha yr). The highest values of soil erosion appear in those areas where overland flow is concentrated and slope steepness is higher. The unpaved trail present the highest values of soil erosion with an average

  5. Mapping the Gap of Water and Erosion Control Measures in the Rapidly Urbanizing Mbezi River Catchment of Dar es Salaam

    Directory of Open Access Journals (Sweden)

    Mhina Given Justin

    2018-01-01

    Full Text Available In rapidly urbanizing catchments, increase in stormwater runoff may cause serious erosion and frequent floods if stormwater management systems are improper and dysfunctional. Through GIS-based modelling, field investigations, resident’s questionnaire survey, and interviews with officials, the study set out to assesses the coverage and efficiency of drainage infrastructure in Mbezi River catchment basin in Dar es Salaam, Tanzania. Between 2003 and 2016, the catchment imperviousness increased by 41%, causing flood incidents, massive erosion, and numerous pollution sources. Residents strive to address stormwater hazards using terraces, hedges, and physical barriers; however, the problems persist, indicating lack of coordination and poor causality understanding between land-use changes and catchment impacts. Small-scale stormwater harvesting was exercised by 75% of the households, pointing to water supply challenges. Municipal stormwater management efforts was limited to roadside drains covering 17% of road lengths in the catchment, and 65% of those did not meet their design standards. Interviews with officials revealed a need for improved co-understanding and collaborative initiatives to bolster integrated water management. The study suggests a need to adopt a new urban stormwater management paradigm, appropriate for both residents and authorities. Without this new discourse, the urbanization led stormwater increase might jeopardize the liveability of the entire catchment.

  6. Effects of DTM resolution on slope steepness and soil loss prediction on hillslope profiles

    Science.gov (United States)

    Eder Paulo Moreira; William J. Elliot; Andrew T. Hudak

    2011-01-01

    Topographic attributes play a critical role in predicting erosion in models such as the Water Erosion Prediction Project (WEPP). The effects of four different high resolution hillslope profiles were studied using four different DTM resolutions: 1-m, 3-m, 5-m and 10-m. The WEPP model used a common scenario encountered in the forest environment and the selected hillslope...

  7. Stochastic runoff connectivity (SRC) equations: integration with erosion models for water quality prediction

    Science.gov (United States)

    Sheridan, G.; Jones, O. D.; Smith, H.; Cawson, J.; Lane, P. J.

    2009-04-01

    In a companion paper at this conference a single-event steady-state rainfall-runoff model (including runoff-runon phenomena) is derived that quantifies the effect of the random spatial arrangement of rainfall and soil properties on i) infiltration-excess runoff delivery at a downslope boundary, and ii) the distribution of the "connected length" (the upslope length with a continuous runoff pathway adjacent to the stream boundary). The accumulation and loss of runoff down a slope is represented as a first-in first-out (FIFO) GI/G/1 queuing system. Runoff rate at a downslope boundary is analogous to the waiting time in the queue in this representation. The distribution of connected length can be represented analytically as a FIFO M/M/1 queuing system, and the mean and variance is derived for this property. Together these distributions characterise the degree of connectivity of the overland flow pathway (and by extension its associated pollutant load) for a given set of rainfall and soil conditions. In this poster, the stochastic runoff connectivity (SRC) model is developed further. We show how the probabilistic SRC model outputs i) and ii) above can be integrated with physically based hillslope scale surface erosion models to predict the probability distribution of constituent (sediment, phosphorous, etc) delivery to the stream boundary. The performance of the model is compared to 2 years of multi-length erosion plot data, and 3 years of continuous small catchment export data from SE Australian forests.

  8. The method of determining surface water erosion influence on agricultural valorization of soils with usage of geoprocessing techniques and spatial information systems

    Directory of Open Access Journals (Sweden)

    Prus Barbara

    2016-12-01

    Full Text Available The aim of the paper is to propose methodical solutions concerning synthetic agricultural analysis of production space which consists in combined (synthetic – in spatial and statistical contexts – analysis and evaluation of quality and farming utility of soils in connection with soils erosive risk level. The paper is aimed at presentation of methodology useful in such type of analyses as well as demonstration to what extent the areas of farming production space being subject to restrictive protection are exposed to destructive effect of surface water erosion. Own factor (HDSP.E was suggested, which is a high degree synthesis of soil protection in connection with degrees of surface water erosion risk. The proposed methodology was used for detailed spatial analyses performed for Tomice – the Małopolska rural commune (case study. The area model elaborated for the proposed methodology’s purpose faced with soils mechanical composition allowed to make a model of surface water erosion in five-grade scale. Synthetic evaluation (product of spatial objects on numerous thematic layers of quality and farming utility of soils and also zones of surface water erosion risk allowed to assign spatial distribution of HDSP.E factor (abbreviation of high degree of soil protection combined with erosion. The analyses enabled to determine proportional contribution of the most valuable resources of farming production space that are subject to soil erosion negative phenomenon. Geoprocessing techniques used for the analyses of environmental elements of farming production space were applied in the paper. The analysis of spatial distribution of researched phenomena was elaborated in Quantum GIS programme.

  9. Erosão em entressulcos sob diferentes tipos de preparo e manejo do solo Interrill soil erosion under different tillage and management systems

    Directory of Open Access Journals (Sweden)

    Elemar Antonino Cassol

    2003-01-01

    Full Text Available A validação de uso de modelos de predição da erosão hídrica do solo baseados em processos físicos fundamentais necessita de informações sobre os valores de seus parâmetros obtidos em condições locais.Este trabalho foi realizado no campo em um Argissolo Vermelho distrófico típico, com o objetivo de avaliar a erosão hídrica em entressulcos sem preparo do solo (com resíduos culturais na superfície, com preparo convencional com solo descoberto (sem resíduos e com preparo convencional com resíduos incorporados. O esquema experimental baseou-se nos estudos realizados para a determinação da erodibilidade do solo em relação ao modelo WEPP (Water Erosion Prediction Project. Foi aplicada chuva simulada com intensidade planejada de 60 mm h-1, durante 70 minutos, e coletadas amostras da enxurrada das parcelas em entressulcos. A perda de solo em entressulcos foi significativamente menor no tratamento sem preparo do solo em relação aos tratamentos submetidos ao preparo convencional. As taxas de erosão e perda de água em entressulcos foram crescentes com o tempo de chuva até atingir um ponto de valor máximo, após o qual decresceram, com exceção do tratamento sem preparo do solo, cujas taxas foram crescentes em todo o período de aplicação da chuva. O valor da erodibilidade do solo em entressulcos é de Ki = 2,83x10(6 kg s m-4.The validation of soil water erosion models based on fundamentals physical processes needs information about the values of their parameters obtained under local conditions. A field study was carried out on a sandy clay loam Palleudult soil in order to evaluate the water erosion in interrill areas under the tillage and management soil systems of no tillage and conventional tillage on bare soil and on soil with residues incorporated. The experimental design was based on field experiments to determine soil erodibility using WEPP (Water Erosion Prediction Project model. Simulated rainfall with intensity of

  10. Finite element analysis of multi-particle impact on erosion in abrasive water jet machining of titanium alloy

    National Research Council Canada - National Science Library

    Kumar, Naresh; Shukla, Mukul

    2012-01-01

    ...) particle impact on erosion of Grade 5 Titanium alloy (Ti-6Al-4V). The influence of abrasive particle impact angle and velocity on the crater sphericity and depth, and erosion rate has been investigated...

  11. Magnitude of Annual Soil Loss from a Hilly Cultivated Slope in Northern Vietnam and Evaluation of Factors Controlling Water Erosion

    Directory of Open Access Journals (Sweden)

    Kiyoshi Kurosawa

    2009-01-01

    Full Text Available A soil erosion experiment was conducted in northern Vietnam over three rainy seasons to clarify the magnitude of soil loss and factors controlling water erosion. The plot had a low (8% or medium (14.5% slope with land-cover of cassava or morning glory or being bare. Annual soil loss (177 to 2,361 g/m2 was a tolerable level in all low-slope plots but was not in some medium-slope plots. The effects of slope gradient and seasonal rainfall on the mean daily soil loss of the season were confirmed, but the effect of land-cover was not, owing to the small canopy cover ratio or leaf area index during the season. The very high annual soil loss (>2,200 g/m2 observed in the first year of some medium-slope plots was the site-specific effect from initial land preparation. Since the site-specific effect was large, the preparation must be done carefully on the slope.

  12. MORPHOPEDOLOGICAL STUDY OF THE ARROIO GUASSUPI WATER BASIN, SÃO PEDRO DO SUL – RIO GRANDE DO SUL (RS: BASIS FOR UNDERSTANDING EROSION PROCESSES

    Directory of Open Access Journals (Sweden)

    Marciel Lohmann

    2005-05-01

    Full Text Available Soil erosion represents one of the most serious environmental problems, jeopardising food production in terms of quality and quantity. It is, therefore, strictly linked to scarcity and starvation. Bertoni & Lobardi Neto (1990 point out that eroded lands have had their productive capacity reduced, making the struggle against erosion fundamental in some parts of the world.In Brazil, around 600 million tons of agricultural soil are lost per year (BAHIA et al 1992. According to Infanti Jr & Fornasari Filho (1998, the phenomena related to erosion formation are caused by two main types of factors or agents: the anthropogenic type, such as deforestation, mining activities and ways of using and occupying the soil (agriculture, construction works, urbanisation, etc., which precipitates the erosion process immediately or after some time; and the natural type, which will determine the intensity of the processes. In this group, we can highlight the rain, vegetation cover, relief, soils and bedrock. When the erosion process takes place under natural or non-disturbed conditions, a permanent balance is established, and no greater damage occurs. However, when this balance is broken, erosion creates serious problems, not only in agriculture, by generating a gradual loss of productivity, but also in the management of water resources, contaminating them with sediment.

  13. Contribution of raindrop impact to the change of soil physical properties and water erosion under semi-arid rainfalls.

    Science.gov (United States)

    Vaezi, Ali Reza; Ahmadi, Morvarid; Cerdà, Artemi

    2017-04-01

    Soil erosion by water is a three-phase process that consists of detachment of soil particles from the soil mass, transportation of detached particles either by raindrop impact or surface water flow, and sedimentation. Detachment by raindrops is a key component of the soil erosion process. However, little information is available on the role of raindrop impact on soil losses in the semi-arid regions where vegetation cover is often poor and does not protect the soil from rainfall. The objective of this study is to determine the contribution of raindrop impact to changes in soil physical properties and soil losses in a semiarid weakly-aggregated agricultural soil. Soil losses were measured under simulated rainfalls of 10, 20, 30, 40, 50, 60 and 70mmh-1, and under two conditions: i) with raindrop impact; and, ii) without raindrop impact. Three replications at each rainfall intensity and condition resulted in a total of 42 microplots of 1m×1.4m installed on a 10% slope according to a randomized complete block design. The contribution of raindrop impact to soil loss was computed using the difference between soil loss with raindrop impact and without raindrop impact at each rainfall intensity. Soil physical properties (aggregate size, bulk density and infiltration rate) were strongly damaged by raindrop impact as rainfall intensity increased. Soil loss was significantly affected by rainfall intensity under both soil surface conditions. The contribution of raindrop impact to soil loss decreased steadily with increasing rainfall intensity. At the lower rainfall intensities (20-30mmh-1), raindrop impact was the dominant factor controlling soil loss from the plots (68%) while at the higher rainfall intensities (40-70mmh-1) soil loss was mostly affected by increasing runoff discharge. At higher rainfall intensities the sheet flow protected the soil from raindrop impact. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Erosion in America

    Energy Technology Data Exchange (ETDEWEB)

    1984-03-23

    The US loses about five billion tons of soil a year from erosion, and scientists estimate that from 20 to 50% of world cropland suffers from excessive erosion. The effect of erosion is a loss in both land and water productivity. When combined with the problems of overpopulation, overgrazing, and deforestation, the environmental impacts are very serious. There are some signs that countries are beginning to adopt conservation tilling techniques, but even cooperative government programs in the US such as the 1983 Payment-in-Kind (PIK) program have had only partial success because of expanded production on marginal farmlands. 20 reference 5 figures.

  15. Flow velocity effect on the corrosion/erosion in water injection systems; Efecto de la velocidad de flujo en la corrosion/erosion en sistemas de inyeccion de agua

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez, C.; Mendez, J. [PDVSA Exploracion y reduccion, Departamento de Ingenieria de Instalaciones, Torres Petroleras EX-MRV, Torre Lama, Piso No. 6, Zulia, Apartado 4013, Venezuela (Venezuela)

    1998-12-31

    The main causes of fails at water injection lines on the secondary petroleum recovery systems are related with corrosion/erosion problems which are influenced by the flow velocity, the presence of dissolved oxygen, solids in the medium and the microorganisms proliferation. So too, this corrosion process promotes the suspended solids generation which affects the water quality injected, causing wells tamponage and loss of injectivity, with the consequent decrease in the crude production. This situation has been impacted in meaning order at the production processes of an exploration enterprise which utilizes the Maracaibo lake as water resource for their injection by pattern projects. Stating that, it was developed a study for determining in experimental order the effect of flow velocity on the corrosion/erosion process joined to the presence of dissolved oxygen which allows to determine the optimum range of the said working velocity for the water injection systems. This range is defined by critical velocities of bio layers deposition and erosion. They were realized simulation pilot tests of the corrosion standard variables, concentration of dissolved oxygen and fluid velocity in the injection systems with filtered and non filtered water. For the development of these tests it was constructed a device which allows to install and expose cylindrical manometers of carbon steel according to predetermined conditions which was obtained the necessary information to make correlations the results of these variables. Additionally, they were determined the mathematical models that adjusts to dynamical behavior of the corrosion/erosion process, finding the optimum range of the flow velocity for the control of this process, being necessary to utilize the following techniques: Scanning Electron Microscopy (SEM), X-ray dispersion analysis (EDX) for encourage the surface studies. They were effected morphological analysis of the surfaces studies and the values were determined of

  16. An application of Landsat and computer technology to potential water pollution from soil erosion

    Science.gov (United States)

    Campbell, W. J.

    1981-01-01

    Agricultural activity has been recognized as the primary source of nonpoint source water pollution. Water quality planners have needed information that is timely, accurate, easily reproducible, and relatively inexpensive to utilize to implement 'Best Management Practices' for water quality. In this paper, a case study shows how the combination of satellite data, which can give accurate land-cover/land-use information, and a computerized geographic information system, can assess nonpoint pollution at a regional scale and be cost effective.

  17. Reducing the impact of soil erosion and reservoir siltation on agricultural production and water availability: the case study of the Laaba catchment (Burkina Faso)

    OpenAIRE

    Coviello, Velio; Vezza, Paolo; Angeluccetti, Irene; Grimaldi, Stefania

    2015-01-01

    Material complementari del cas estudi "Reducing the impact of soil erosion and reservoir siltation on agricultural production and water availability: the case study of the Laaba catchment (Burkina Faso)", part component del llibre "Case studies for developing globally responsible engineers" Peer Reviewed

  18. Impact of erosion and transfer processes in Polycyclic Aromatic Hydrocarbon contamination of water bodies in the Seine River basin (France)

    Science.gov (United States)

    Gateuille, David; Evrard, Olivier; Moreau-Guigon, Elodie; Chevreuil, Marc; Mouchel, Jean-Marie

    2014-05-01

    Polycyclic Aromatic Hydrocarbons (PAHs) reach problematic concentrations in water and sediment of numerous streams of the world. In the Seine River (France), they prevent to achieve the good chemical status enforced by European law. However, the provenance and the fate of PAHs found in rivers are still poorly understood. Here, we combined chemical and fallout radionuclide measurements conducted on a large number of suspended sediment (SS) (n = 231) and soil (n = 37) samples collected at 62 sites during an entire hydrological year. A model was developed to estimate mean PAH concentration in sediment from the population density in the drainage area and good relationships were found during both low stage and flood periods. Influence of human population also appeared to be stronger during the latter period. However, some discrepancies between measured and modeled PAH concentrations were observed and the role of the origin of SS was investigated. During the low flow period, the observed differences were explained by the provenance of river sediment (agricultural topsoil vs. eroded channel banks). Time-averaged PAH concentrations measured in suspended sediment collected in the catchments where erosion of agricultural topsoil dominated were systematically higher than the predicted values. On the contrary, in the catchments where erosion mainly occurred in deep soil or river embankment, the supply of particles protected from atmospheric fallout contamination led to measure concentrations below the predicted values. As this relationship between population density and SS contamination was no longer valid during the flood period, the role of transfer times was also investigated. The percentages of freshly eroded sediment in samples were determined by comparing the 7Be/210Pb ratio in rainfall and SS. An annual turn-over cycle of sediment was observed but no relationship was found between PAH contamination and residence times of particles within rivers. This result suggested

  19. Ditch blocking, water chemistry and organic carbon flux: evidence that blanket bog restoration reduces erosion and fluvial carbon loss.

    Science.gov (United States)

    Wilson, Lorraine; Wilson, Jared; Holden, Joseph; Johnstone, Ian; Armstrong, Alona; Morris, Michael

    2011-05-01

    The potential for restoration of peatlands to deliver benefits beyond habitat restoration is poorly understood. There may be impacts on discharge water quality, peat erosion, flow rates and flood risk, and nutrient fluxes. This study aimed to assess the impact of drain blocking, as a form of peatland restoration, on an upland blanket bog, by measuring water chemistry and colour, and loss of both dissolved (DOC) and particulate organic carbon (POC). The restoration work was designed to permit the collection of a robust experimental dataset over a landscape scale, with data covering up to 3 years pre-restoration and up to 3 years post-restoration. An information theoretic approach to data analyses provided evidence of a recovery of water chemistry towards more 'natural' conditions, and showed strong declines in the production of water colour. Drain blocking led to increases in the E4:E6 ratio, and declines in specific absorbance, suggesting that DOC released from blocked drains consisted of lighter, less humic and less decomposed carbon. Whilst concentrations of DOC showed slight increases in drains and streams after blocking, instantaneous yields of both DOC and POC declined markedly in streams over the first year post-restoration. Attempts were made to estimate total annual fluvial organic carbon fluxes for the study site, and although errors around these estimates remain considerable, there is strong evidence of a large reduction in aquatic organic carbon flux from the peatland following drain-blocking. Potential mechanisms for the observed changes in water chemistry and organic carbon release are discussed, and we highlight the need for more detailed information, from more sites, to better understand the full impacts of peatland restoration on carbon storage and release. Copyright © 2011 Elsevier B.V. All rights reserved.

  20. Splash erosion

    NARCIS (Netherlands)

    Fernández-Raga, María; Palencia, Covadonga; Keesstra, Saskia; Jordán, Antonio; Fraile, Roberto; Angulo-Martínez, Marta; Cerda Bolinches, Artemio

    2017-01-01

    Soil erosion is a serious ecological and environmental problem, and the main cause of land degradation in many ecosystems at global scale. Detachment of soil particles by raindrop splash is the first stage in the soil erosion process. A review of the scientific literature published in

  1. Impacts of climate change and establishing a vegetation cover on water erosion of contaminated spoils for two contrasting United Kingdom regional climates: a case study approach.

    Science.gov (United States)

    De Munck, Cécile S; Hutchings, Tony R; Moffat, Andy J

    2008-10-01

    This study examines how pollutant linkage of contaminants will be influenced by predicted changes in precipitation and subsequent rainfall erosion of soils and spoils in the United Kingdom during the 21st century. Two contrasting regional climates were used in conjunction with 2 extreme emissions scenarios (low and high greenhouse gas emissions) to run the Revised Universal Soil Loss Equation 2 (RUSLE2) model for a case study that represents a high risk of pollutant linkage through water erosion. Results for the 2 scenarios and the 2 regions showed a significant and gradual increase in erosion rates with time as a consequence of climate change, by up to 32% for the southwest and 6.6% for the southeast regions by the 2080s. Revegetation of the site showed a dramatic reduction in predicted future amounts of sediment production and subsequent contaminant movement, well below existing levels. Limitations and future improvements of the methodology are discussed.

  2. [Vegetation above-ground biomass and its affecting factors in water/wind erosion crisscross region on Loess Plateau].

    Science.gov (United States)

    Wang, Jian-guo; Fan, Jun; Wang, Quan-jiu; Wang, Li

    2011-03-01

    Field investigations were conducted in Liudaogou small watershed in late September 2009 to study the differences of vegetation above-ground biomass, soil moisture content, and soil nutrient contents under different land use patterns, aimed to approach the vegetation above-ground biomass level and related affecting factors in typical small watershed in water/wind erosion crisscross region on Loess Plateau. The above-ground dry biomass of the main vegetations in Liudaogou was 177-2207 g x m(-2), and that in corn field, millet field, abandoned farmland, artificial grassland, natural grassland, and shrub land was 2097-2207, 518-775, 248-578, 280-545, 177-396, and 372-680 g x m(-2), respectively. The mean soil moisture content in 0-100 layer was the highest (14.2%) in farmlands and the lowest (10.9%) in shrub land. The coefficient of variation of soil moisture content was the greatest (26. 7% ) in abandoned farmland, indicating the strong spatial heterogeneity of soil moisture in this kind of farmland. The mean soil water storage was in the order of farmland > artificial grassland > natural grassland > shrub land. Soil dry layer was observed in alfalfa and caragana lands. There was a significant positive correlation (r = 0.639, P nutrient contents, but had no significant correlations with elevation, slope gradient, slope aspect, and soil bulk density.

  3. Comparison of water soil erosion on Spanish Mediterannean abandoned land and agricultural fields under vine, almond, olives and citrus

    Science.gov (United States)

    Rodrigo-Comino, Jesús; Martínez-Hernández, Carlos; Iserloh, Thomas; Cerdà, Artemi

    2017-04-01

    The abandonment of agricultural lands is considered as a global dynamic with on- and off-site consequences on the soil mostly ignored (Vanmaercke et al., 2011), which enhance land degradation processes by increasing water soil erosion (Cammeraat et al., 2010; Keesstra et al., 2012) and by decreasing biodiversity (Brevik et al., 2015; Smith et al., 2015). However, there is a lack of information at pedon scale about the assessment and quantification of which environmental elements activate or avoid water soil erosion after its respective abandonment. Small portable rainfall simulators are considered as useful tool for measuring interrelated soil erosion processes such as splash, initial rainfall-runoff processes, infiltration, sediment yield, water turbidity or nutrient suspensions (Cerdà, 1999; Iserloh et al., 2013; Rodrigo Comino et al., 2016). 105 experiments were conducted with a small portable rainfall simulator (rainfall intensity of 40 mm h-1 in 30 minutes) in four different land uses and their respective abandoned land: i) citrus and olives (Valencia), almonds (Murcia) and vines (Málaga). We studied the main environmental factors that may determine water soil erosion during the performed experiments: slope, vegetation cover, rock fragment cover, soil properties (texture) and hydrological responses (time to runoff and infiltration generation). REFERENCES Brevik, E.C., Cerdà, A., Mataix-Solera, J., Pereg, L., Quinton, J.N., Six, J., Van Oost, K., 2015. The interdisciplinary nature of SOIL. SOIL 1, 117-129. doi:10.5194/soil-1-117-2015 Cammeraat, E.L.H., Cerdà, A., Imeson, A.C., 2010. Ecohydrological adaptation of soils following land abandonment in a semi-arid environment. Ecohydrology 3, 421-430. doi:10.1002/eco.161 Cerdà, A., 1999. Simuladores de lluvia y su aplicación a la Geomorfología: Estado de la cuestión. Cuad. Investig. Geográfica 45-84. Iserloh, T., Ries, J.B., Arnáez, J., Boix-Fayos, C., Butzen, V., Cerdà, A., Echeverría, M.T., Fern

  4. Soil Erosion and Surface Water Quality Impacts of Natural Gas Development in East Texas, USA

    Directory of Open Access Journals (Sweden)

    Matthew McBroom

    2012-11-01

    Full Text Available Due to greater demands for hydrocarbons and improvements in drilling technology, development of oil and natural gas in some regions of the United States has increased dramatically. A 1.4 ha natural gas well pad was constructed in an intermittent stream channel at the Alto Experimental Watersheds in East Texas, USA (F1, while another 1.1 ha well pad was offset about 15 m from a nearby intermittent stream (F2. V-notch weirs were constructed downstream of these well pads and stream sedimentation and water quality was measured. For the 2009 water year, about 11.76 cm, or almost 222% more runoff resulted from F1 than F2. Sediment yield was significantly greater at F1, with 13,972 kg ha−1 yr−1 versus 714 kg ha−1yr−1 at F2 on a per unit area disturbance basis for the 2009 water year. These losses were greater than was observed following forest clearcutting with best management practices (111–224 kg ha−1. Significantly greater nitrogen and phosphorus losses were measured at F1 than F2. While oil and gas development can degrade surface water quality, appropriate conservation practices like retaining streamside buffers can mitigate these impacts.

  5. Comparing simple and complex approaches to simulate the impacts of soil water repellency on runoff and erosion in burnt Mediterranean forest slopes

    Science.gov (United States)

    Nunes, João Pedro; Catarina Simões Vieira, Diana; Keizer, Jan Jacob

    2017-04-01

    Fires impact soil hydrological properties, enhancing soil water repellency and therefore increasing the potential for surface runoff generation and soil erosion. In consequence, the successful application of hydrological models to post-fire conditions requires the appropriate simulation of the effects of soil water repellency on soil hydrology. This work compared three approaches to model soil water repellency impacts on soil hydrology in burnt eucalypt and pine forest slopes in central Portugal: 1) Daily approach, simulating repellency as a function of soil moisture, and influencing the maximum soil available water holding capacity. It is based on the Thornthwaite-Mather soil water modelling approach, and is parameterized with the soil's wilting point and field capacity, and a parameter relating soil water repellency with water holding capacity. It was tested with soil moisture data from burnt and unburnt hillslopes. This approach was able to simulate post-fire soil moisture patterns, which the model without repellency was unable to do. However, model parameters were different between the burnt and unburnt slopes, indicating that more research is needed to derive standardized parameters from commonly measured soil and vegetation properties. 2) Seasonal approach, pre-determining repellency at the seasonal scale (3 months) in four classes (from none to extreme). It is based on the Morgan-Morgan-Finney (MMF) runoff and erosion model, applied at the seasonal scale and is parameterized with a parameter relating repellency class with field capacity. It was tested with runoff and erosion data from several experimental plots, and led to important improvements on runoff prediction over an approach with constant field capacity for all seasons (calibrated for repellency effects), but only slight improvements in erosion predictions. In contrast with the daily approach, the parameters could be reproduced between different sites 3) Constant approach, specifying values for soil

  6. Soil erosion in humid regions: a review

    Science.gov (United States)

    Daniel J. Holz; Karl W.J. Williard; Pamela J. Edwards; Jon E. Schoonover

    2015-01-01

    Soil erosion has significant implications for land productivity and surface water quality, as sediment is the leading water pollutant worldwide. Here, erosion processes are defined. The dominant factors influencing soil erosion in humid areas are reviewed, with an emphasis on the roles of precipitation, soil moisture, soil porosity, slope steepness and length,...

  7. Development of a model to predict ash transport and water pollution risk in fire-affected environments

    Science.gov (United States)

    Neris, Jonay; Elliot, William J.; Doerr, Stefan H.; Robichaud, Peter R.

    2017-04-01

    An estimated that 15% of the world's population lives in volcanic areas. Recent catastrophic erosion events following wildfires in volcanic terrain have highlighted the geomorphological instability of this soil type under disturbed conditions and steep slopes. Predicting the hydrological and erosional response of this soils in the post-fire period is the first step to design and develop adequate actions to minimize risks in the post-fire period. In this work we apply, for the first time, the Water Erosion Prediction Project model for predicting erosion and runoff events in fire-affected volcanic soils in Europe. Two areas affected by wildfires in 2015 were selected in Tenerife (Spain) representative of different fire behaviour (downhill surface fire with long residence time vs uphill crown fire with short residence time), severity (moderate soil burn severity vs light soil burn severity) and climatic conditions (average annual precipitation of 750 and 210 mm respectively). The actual erosion processes were monitored in the field using silt fences. Rainfall and rill simulations were conducted to determine hydrologic, interrill and rill erosion parameters. The soils were sampled and key properties used as model input, evaluated. During the first 18 months after the fire 7 storms produced runoff and erosion in the selected areas. Sediment delivery reached 5.4 and 2.5 Mg ha-1 respectively in the first rainfall event monitored after the fire, figures comparable to those reported for fire-affected areas of the western USA with similar climatic conditions but lower than those showed by wetter environments. The validation of the WEPP model using field data showed reasonable estimates of hillslope sediment delivery in the post-fire period and, therefore, it is suggested that this model can support land managers in volcanic areas in Europe in predicting post-fire hydrological and erosional risks and designing suitable mitigation treatments.

  8. A comparison of the geochemical signatures of water-rock interaction and erosion rates between developed and undeveloped watersheds, St. John, US Virgin Islands

    Science.gov (United States)

    Gudino, N.; Kretzschmar, T.; Gray, S. C.

    2012-12-01

    Human activities such as deforestation, agriculture, and the building of dirt roads may increase soil erosion and the delivery of land-based sediment into coastal waters from steep sub-tropical islands. These changes may also affect water-rock interaction, which alters the geochemistry of storm waters and the clay mineralogy of eroded sediments. In the US Virgin Islands, land-based sedimentation is thought to be a major cause of the decline of near-shore coral reefs. The objective of this study was to 1) evaluate whether chemical erosion (water-rock interaction) during storms affected the major-element chemistry of storm-water and the clay mineralogy of eroded sediments; and 2) determine if enhanced erosion associated with human activities may impact these parameters. Our approach was to compare storm-water and sediment geochemistry and modeled erosion rates between developed (Coral Bay) and undeveloped (Lameshur) watersheds on St. John, USVI. Terrestrial and marine sediment samples and runoff samples from three storm events, including Hurricane Otto (Oct. 7-9th), were collected during the 2010 hurricane season in Coral Bay and Lameshur watersheds and bays. Major elements in storm waters were measured using ICP-AES. The mineral saturation index was calculated using "The Geochemist's Workbench" (GWB), supported by X-Ray Diffraction analysis on clay minerals. The Revised and Modified Universal Soil Loss Equations were used to estimate both annual mean (2010, RUSLE) and storm-event (Hurricane Otto, MUSLE) based erosion rates. In addition, rates of marine terrigenous sediment accumulation were estimated by Loss On Ignition (LOI) analysis of marine sediment collected using submarine sediment trap arrays. Spatial variations in calcium, magnesium, sodium and potassium concentrations in storm water samples were measured and only calcium was statistical different (p<0.05) between the developed and undeveloped study sites during Hurricane Otto. Event specific differences in

  9. Experimental Study of Laser Cladding Methods on Water Erosion Resistance to Low Pressure Blades Materials of Steam Turbine

    Directory of Open Access Journals (Sweden)

    Di Zhang

    2014-01-01

    Full Text Available An experimental apparatus was built to study the effects of liquid-solid impact on laser cladding processing specimens of 17-4PH stainless steel material in the present investigation. Then the result of specimens without laser surface process was compared. The impact effect on the specimens was observed using the three-dimensional digital microscope. The depth of laser cladding and substrate material caused by liquid droplet impact was studied in detail and measured. The accuracy and reliability of the experimental system and computing methods were also verified. The depth of the impact area of laser cladding specimens was distributed in the range of 0.5–1.5 μm while the 17-4PH group was distributed in the range of 2.5–3.5 μm. In contrast with specimens without laser surface processing, the material processed by laser cladding has significantly higher resistance to water erosion.

  10. Long-Term Impact of Sediment Deposition and Erosion on Water Surface Profiles in the Ner River

    Directory of Open Access Journals (Sweden)

    Tomasz Dysarz

    2017-02-01

    Full Text Available The purpose of the paper is to test forecasting of the sediment transport process, taking into account two main uncertainties involved in sediment transport modeling. These are: the lack of knowledge regarding future flows, and the uncertainty with respect to which sediment transport formula should be chosen for simulations. The river reach chosen for study is the outlet part of the Ner River, located in the central part of Poland. The main characteristic of the river is the presence of an intensive morphodynamic process, increasing flooding frequency. The approach proposed here is based on simulations with a sediment-routing model and assessment of the hydraulic condition changes on the basis of hydrodynamic calculations for the chosen characteristic flows. The data used include Digital Terrain Models (DTMs, cross-section measurements, and hydrological observations from the Dabie gauge station. The sediment and hydrodynamic calculations are performed using program HEC-RAS 5.0. Twenty inflow scenarios are of a 10-year duration and are composed on the basis of historical data. Meyer-Peter and Müller and Engelund-Hansen formulae are applied for the calculation of sediment transport intensity. The methodology presented here seems to be a good tool for the prediction of long-term impacts on water surface profiles caused by sediment deposition and erosion.

  11. Impact of the changes in the chemical composition of pore water on chemical and physical stability of natural clays. A review of natural cases and related laboratory experiments and the ideas on natural analogues for bentonite erosion/non-erosion

    Energy Technology Data Exchange (ETDEWEB)

    Puura, Erik (Eridicon OUe, Tartu (Estonia)); Kirsimaee, Kalle (Univ. of Tartu, Inst. of Ecology and Earth Sciences, Tartu (Estonia))

    2010-01-15

    A scientific literature survey was compiled with the specific objective to find information for smectite mobilization and/or retention in natural clay formations caused by contact with water with low ionic concentrations such as can be expected during and after an ice age. Evidence was sought if smectite particles are lost from the clay to the water and if accessory minerals that remain could form a growing filter slowing down or stopping further loss of smectite. Bentonites are present in geological layers for hundreds of millions of years. There is limited exchange with surrounding layers, eg K transported into the bentonite layer from surrounding shale layers leading to the increased illite % in smectite-illite of the bentonite. Another process is silicification of surrounding layers leading to lowered permeability of surrounding rocks. Geological literature data on historical bentonites do not consider colloid formation in low ionic strength water as relevant mechanism for smectite mobilization. However there are no studied cases where this could be a relevant mechanism (as proposed by colloid release scenario). Soil researchers have studied the mechanism of colloid release in laboratory experiments and have found that there has to be an abrupt change in infiltrating water quality leading to 'osmotic explosion'. Clogging the pores in the lower part of the soil column has followed, leading to dramatic decrease of hydraulic conductivity in vertical profile and increased surface runoff. So, although limited, there are literature evidences of clay colloids release from bentonites/smectites caused by low-ionic circumneutral water. The geological settings to look for natural analogue studies include (1) Bentonite/smectite similar to what is used in repository. (2) Water similar to the composition of glacial meltwater. (3) Scenario similar to what is proposed in the bentonite erosion project. The problem related to the study of historical bentonite profiles

  12. Effectiveness of the GAEC cross-compliance standard Short-term measures for runoff water control on sloping land (temporary ditches and grass strips in controlling soil erosion

    Directory of Open Access Journals (Sweden)

    Paolo Bazzoffi

    2011-08-01

    Full Text Available The agronomic measures made obligatory by the cross-compliance Standard Temporary measures for runoff water control on sloping land included in the Ministry of Agricultural, Food and Forestry Policies (MiPAAF decree on cross compliance until 2008, and by Standard 1.1 Creation of temporary ditches for the prevention of soil erosion in the 2009 decree, certainly appear to be useful for the control of soil erosion and runoff. The efficacy of temporary drainage ditches and of grass strips in controlling runoff and erosion has been demonstrated in trials conducted in field test plots in Italy. When level temporary drainage ditches are correctly built, namely with an inclination of not more than 2.5% in relation to the maximum hillslope gradient, they allow the suspended sediment eroded upstream to settle in the ditches, retaining the material carried away on the slope and, as a result, reducing the quantity of sediment delivered to the hydrographic network. In particular, among all the results, the erosion and runoff data in a trial conducted in Guiglia (Modena showed that in corn plots, temporary drainage ditches reduced soil erosion by 94%, from 14.4 Mg ha-1 year-1 (above the limit established by the NRCS-USDA of 11.2 Mg ha-1 year-1 to 0.8 Mg ha-1 year-1 (within the NRCS limit and also within the more restrictive limit established by the OECD of 6.0 Mg ha-1 year-1. With respect to the grass buffer strips the most significant research was carried out in Volterra. This research demonstrated their efficacy in reducing erosion from 8.15 Mg ha-1 to 1.6 Mg ha-1, which is approximately 5 times less than the erosion observed on bare soil. The effectiveness of temporary drainage ditches was also assessed through the application of the Revised Universal Soil Loss Equation (RUSLE erosion model to 60 areas under the control of the Agency for Agricultural Payments (AGEA in 2009, comparing the risk of erosion in these sample areas by simulating the presence and

  13. Water erosion and soil protection technology in the agro-industrial farms around the Wadi El Ouaar, Taroudant sedimentary fan, Morocco

    Science.gov (United States)

    Ghafrani, Hassan; Hssaine, Ali Ait

    2013-04-01

    , there is still no final solution found. In this area, the results of erosion control are not always satisfactory due to lack of study, consultation and experience in the conservation of soil and water of the farmers. Under these conditions the government is virtually absent and farmers are not organized or supervised in their fight against the gullies. The random effort and uncoordinated interventions of farmers emphasize occasionally the socio-economic and environmental impacts of this phenomenon.

  14. Soil Erosion. LC Science Tracer Bullet.

    Science.gov (United States)

    Buydos, John F., Comp.

    Soil erosion is the detachment and movement of topsoil or soil material from the upper part of the soil profile. It may occur in the form of rill, gully, sheet, or wind erosion. Agents of erosion may be water, wind, glacial ice, agricultural implements, machinery, and animals. Soil conservation measures require a thorough understanding of the…

  15. Effects of Long-term Conservation Tillage on Soil Nutrients in Sloping Fields in Regions Characterized by Water and Wind Erosion

    Science.gov (United States)

    Tan, Chunjian; Cao, Xue; Yuan, Shuai; Wang, Weiyu; Feng, Yongzhong; Qiao, Bo

    2015-12-01

    Conservation tillage is commonly used in regions affected by water and wind erosion. To understand the effects of conservation tillage on soil nutrients and yield, a long-term experiment was set up in a region affected by water and wind erosion on the Loess Plateau. The treatments used were traditional tillage (CK), no tillage (NT), straw mulching (SM), plastic-film mulching (PM), ridging and plastic-film mulching (RPM) and intercropping (In). Our results demonstrate that the available nutrients in soils subjected to non-traditional tillage treatments decreased during the first several years and then remained stable over the last several years of the experiment. The soil organic matter and total nitrogen content increased gradually over 6 years in all treatments except CK. The nutrient content of soils subjected to conservative tillage methods, such as NT and SM, were significantly higher than those in soils under the CK treatment. Straw mulching and film mulching effectively reduced an observed decrease in soybean yield. Over the final 6 years of the experiment, soybean yields followed the trend RPM > PM > SM > NT > CK > In. This trend has implications for controlling soil erosion and preventing non-point source pollution in sloping fields by sacrificing some food production.

  16. Modelling of steady state erosion of CFC actively water-cooled mock-up for the ITER divertor

    Science.gov (United States)

    Ogorodnikova, O. V.

    2008-04-01

    Calculations of the physical and chemical erosion of CFC (carbon fibre composite) monoblocks as outer vertical target of the ITER divertor during normal operation regimes have been done. Off-normal events and ELM's are not considered here. For a set of components under thermal and particles loads at glancing incident angle, variations in the material properties and/or assembly of defects could result in different erosion of actively-cooled components and, thus, in temperature instabilities. Operation regimes where the temperature instability takes place are investigated. It is shown that the temperature and erosion instabilities, probably, are not a critical point for the present design of ITER vertical target if a realistic variation of material properties is assumed, namely, the difference in the thermal conductivities of the neighbouring monoblocks is 20% and the maximum allowable size of a defect between CFC armour and cooling tube is +/-90° in circumferential direction from the apex.

  17. Geospatial Assessment of Long-Term Sustainability of Biomass Feedstock Supplies: Erosion, Soil Biomass Accumulation, Greenhouse Gasses

    Science.gov (United States)

    Rosentrater, K. A.; Kaleita, A. L.

    2013-12-01

    In the past decade, the corn grain-based fuel ethanol industry has grown exponentially. Now, stakeholders within the corn grain producing regions of the midwestern United States are seeking to develop advanced biofuels from abundant post-harvest lignocellulosic corn stover resides. How sustainable are these biofuels? Scientific guidelines regarding the sustainable use of corn grain and stover to maintain soil quality have not been clearly defined, due in part to the complexity of agricultural soil systems and the dearth of robust and consistent data. The objective of this study was to examine the long-term sustainability of corn stover harvest for economically relevant agricultural production scenarios focused on the state of Iowa. We used the Water Erosion Prediction Project (WEPP) model to simulate soil erosion and biomass returned to the soil under two crop rotation scenarios (continuous corn vs. corn-soybean rotation), three corn stover removal rates (0, 50, 100% removed), and three tillage intensities (no till (NT), intermediate till (IT), conventional till (CT)). Calculations were aggregated to the township-scale using multiple sampling points from the USDA Natural Resources Inventory per township within each county, for a total of 17,848 sampling points throughout the state. This accounted for the topographical and soils variation within the state; use of county weather stations incorporated climate variations. Statistical characterization and GIS visualization were used to illustrate and interpret the results. Wide variations in biomass accumulation/erosion/GHG impacts were observed across agronomic scenarios and landform regions throughout Iowa, and biomass management and tillage intensity impacted on-site soil quality and the off-site environment. Soil biomass was primarily affected by stover removal rate, with soybean rotation also reducing soil biomass. Soil erosion was primarily affected by slope and tillage, with stover removal rate playing a lesser

  18. Residual effect of soil tillage on water erosion from a Typic Paleudalf under long-term no-tillage and cropping systems

    Directory of Open Access Journals (Sweden)

    Mastrângello Enívar Lanzanova

    2013-12-01

    Full Text Available Soil erosion is one of the chief causes of agricultural land degradation. Practices of conservation agriculture, such as no-tillage and cover crops, are the key strategies of soil erosion control. In a long-term experiment on a Typic Paleudalf, we evaluated the temporal changes of soil loss and water runoff rates promoted by the transition from conventional to no-tillage systems in the treatments: bare soil (BS; grassland (GL; winter fallow (WF; intercrop maize and velvet bean (M+VB; intercrop maize and jack bean (M+JB; forage radish as winter cover crop (FR; and winter cover crop consortium ryegrass - common vetch (RG+CV. Intensive soil tillage induced higher soil losses and water runoff rates; these effects persisted for up to three years after the adoption of no-tillage. The planting of cover crops resulted in a faster decrease of soil and water loss rates in the first years after conversion from conventional to no-tillage than to winter fallow. The association of no-tillage with cover crops promoted progressive soil stabilization; after three years, soil losses were similar and water runoff was lower than from grassland soil. In the treatments of cropping systems with cover crops, soil losses were reduced by 99.7 and 66.7 %, compared to bare soil and winter fallow, while the water losses were reduced by 96.8 and 71.8 % in relation to the same treatments, respectively.

  19. Bentonite erosion. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Birgersson, Martin; Boergesson, Lennart; Hedstroem, Magnus; Karnland, Ola; Nilsson, Ulf (Clay Technology AB, Lund (Sweden))

    2009-12-15

    Low saline water may reach KBS-3 repository depth, e.g. during periods of glaciation. Under such aqueous conditions, the montmorillonite part of the bentonite buffer might transform into a sol and thereby be transported away with flowing water in fractures. The primary aim with this report is to improve the understanding of the basic principles for this possible montmorillonite particle release. The report includes experimental and theoretical work performed at Clay Technology. Natural bentonite and ion-exchanged purified montmorillonite from three different geographical origins, Wyoming (U.S.), Milos (Greece) and Kutch (India) have been studied. Experimental and/or theoretical investigations have been performed with respect to: - Free swelling ability; - Rheological properties; - Rate of bentonite loss into fractures; - Filtering; - Ion exchange; - Sol formation ability; - Ion diffusion; - Mass loss due to erosion. The performed erosion experiments show that erosion does not occur in a mixed calcium/sodium montmorillonite with at least 20% calcium in exchange positions, when the external solution contains above 4 mM charge equivalents. This result is in agreement with the presented conceptual view of sol formation and measured equilibrium properties in mixed calcium/sodium montmorillonite. The findings imply that the buffer will be stable for non-glacial conditions. However, erosion due to sol formation cannot be ruled out for glacial conditions.

  20. Modelling the effect of support practices (P-factor) on the reduction of soil erosion by water at European Scale

    NARCIS (Netherlands)

    Panagos, P.; Borrelli, P.; Meusburger, K.; van der Zanden, E.H.; Poesen, J.; Alewell, C.

    2015-01-01

    The USLE/RUSLE support practice factor (P-factor) is rarely taken into account in soil erosion risk modelling at sub-continental scale, as it is difficult to estimate for large areas. This study attempts to model the P-factor in the European Union. For this, it considers the latest policy

  1. Erhversbetinget erosion?

    DEFF Research Database (Denmark)

    Dige, Irene; Gjørup, Hans; Nyvad, Bente

    2012-01-01

    Baggrund – I forbindelse med dental erosion er en grundig udredning af patienten vigtig, således at årsagen til erosionernes opståen findes, og der kan iværksættes adækvat forebyggende indsats. En sådan udredning er ikke mindst vigtig, når arbejdsmiljøet mistænkes. Patienttilfælde – En 30-årig...... arbejdsskade, men ikke anerkendt, da erosioner ikke er optaget på Arbejdsskadestyrelsens liste over erhvervssygdomme. En systematisk registrering af lignende tilfælde kunne imidlertid på sigt ændre retspraksis for fremtidige patienter med arbejdsbetinget erosion....

  2. Sediment transport in forested head water catchments - Calibration and validation of a soil erosion and landscape evolution model

    Science.gov (United States)

    Hancock, G. R.; Webb, A. A.; Turner, L.

    2017-11-01

    Sediment transport and soil erosion can be determined by a variety of field and modelling approaches. Computer based soil erosion and landscape evolution models (LEMs) offer the potential to be reliable assessment and prediction tools. An advantage of such models is that they provide both erosion and deposition patterns as well as total catchment sediment output. However, before use, like all models they require calibration and validation. In recent years LEMs have been used for a variety of both natural and disturbed landscape assessment. However, these models have not been evaluated for their reliability in steep forested catchments. Here, the SIBERIA LEM is calibrated and evaluated for its reliability for two steep forested catchments in south-eastern Australia. The model is independently calibrated using two methods. Firstly, hydrology and sediment transport parameters are inferred from catchment geomorphology and soil properties and secondly from catchment sediment transport and discharge data. The results demonstrate that both calibration methods provide similar parameters and reliable modelled sediment transport output. A sensitivity study of the input parameters demonstrates the model's sensitivity to correct parameterisation and also how the model could be used to assess potential timber harvesting as well as the removal of vegetation by fire.

  3. Comparative effects of oil palm and selective logging on erosion, river channels and water chemistry in Malaysian steeplands

    Science.gov (United States)

    Walsh, Rory; Nainar, Anand; Nurhidayu, Siti; Higton, Sam; Annammala, Kogilavani; Wall, Katy; Bidin, Kawi; Blake, William; Darling, Isabella

    2017-04-01

    Oil palm land-use has expanded greatly in recent decades in SE Asia and other parts of the wet tropics, including to steepland areas, where bench-terraced landscaping is involved. Retaining (and sometimes restoring) riparian forest strips and rainforest fragments on the steepest slopes have been adopted as elements of strategies designed to reduce adverse effects on runoff generation, erosion, downstream sedimentation, flooding and pollutional problems - as well as biodiversity and emissions. Results of catchment monitoring, soil erosion and sediment fingerprinting research in oil palm and selectively logged steeplands of eastern Sabah and Peninsular Malaysia are presented. The evidence indicates the greater scale and temporal persistence of effects that oil palm land-use (compared with selective logging) has had on suspended sediment dynamics, soil erosion, downstream sedimentation, channel geometry and dynamics and river pollution. The importance of (1) high densities of roads and tracks and (2) relatively impermeable bench-terraced terrain in enhancing runoff, sediment and nutrient outputs in storm events is stressed. Influences of oil palm management practices including riparian forest strips in increasing or reducing these effects are critically reviewed and ways of increasing the effectiveness of riparian forest strips are proposed. The design and rationale of current projects exploring and testing consequences of existing and proposed improved land management practices are briefly described. The key importance of involvement of people from the oil palm industry (including multinational companies, smallholders and their organizations) and Government bodies that are responsible for land-use policies and land management practices is stressed.

  4. Effect of carbonated beverages, coffee, sports and high energy drinks, and bottled water on the in vitro erosion characteristics of dental enamel.

    Science.gov (United States)

    Kitchens, Michael; Owens, Barry M

    2007-01-01

    This study evaluated the effect of carbonated and non-carbonated beverages, bottled and tap water, on the erosive potential of dental enamel with and without fluoride varnish protection. Beverages used in this study included: Coca Cola Classic, Diet Coke, Gatorade sports drink, Red Bull high-energy drink, Starbucks Frappuccino coffee drink, Dasani water (bottled), and tap water (control). Enamel surfaces were coated with Cavity Shield 5% sodium fluoride treatment varnish. Twenty-eight previously extracted human posterior teeth free of hypocalcification and caries were used in this study. The coronal portion of each tooth was removed and then sectioned transverse from the buccal to lingual surface using a diamond coated saw blade. The crown sections were embedded in acrylic resin blocks leaving the enamel surfaces exposed. The enamel surfaces were polished using 600 to 2000 grit abrasive paper and diamond paste. Test specimens were randomly distributed to seven beverage groups and comprised 4 specimens per group. Two specimens per beverage group were treated with a fluoride varnish while 2 specimens did not receive fluoride coating. Surface roughness (profilometer) readings were performed at baseline (prior to fluoride treatment and immersion in the beverage) and again, following immersion for 14 days (24 hours/day). The test beverages were changed daily and the enamel specimens were immersed at 37 degrees C. Surface roughness data was evaluated using multiple factor ANOVA at a significance level of pStarBucks coffee, Dasani water, and tap water. Fluoride varnish was not a significant impact factor; however, beverage (type) and exposure time were significant impact variables. Both carbonated and non-carbonated beverages displayed a significant erosive effect on dental enamel; however, fluoride varnish treatments did not demonstrate a significant protective influence on enamel surfaces.

  5. Backward erosion piping : Initiation and progression

    NARCIS (Netherlands)

    Van Beek, V.M.

    2015-01-01

    Backward erosion piping is an internal erosion mechanism during which shallow pipes are formed in the direction opposite to the flow underneath water-retaining structures as a result of the gradual removal of sandy material by the action of water. It is an important failure mechanism in both dikes

  6. Modelling the effect of support practices (P-factor) on the reduction of soil erosion by water at European scale

    OpenAIRE

    Panagos, Panos; Borrelli, Pasquale; Meusburger, Katrin; van der Zanden, Emma H; Poesen, Jean; Alewell, Christine

    2015-01-01

    The USLE/RUSLE support practice factor (P-factor) is rarely taken into account in soil erosion risk modelling at sub-continental scale, as it is difficult to estimate for large areas. This study attempts to model the P-factor in the European Union. For this, it considers the latest policy developments in the Common Agricultural Policy, and applies the rules set by Member States for contour farming over a certain slope. The impact of stone walls and grass margins is also modelled using the mor...

  7. The impacts of climate change on soils. Investigations of impacts of climate change on soil erosion by water; Wirkungen der Klimaaenderungen auf die Boeden. Untersuchungen zu Auswirkungen des Klimawandels auf die Bodenerosion durch Wasser

    Energy Technology Data Exchange (ETDEWEB)

    Wurbs, Daniel [Geoflux GbR, Halle (Saale) (Germany); Steininger, Michael [Mitteldeutsches Institut fuer angewandte Standortkunde und Bodenschutz (MISB), Halle (Saale) (Germany)

    2011-03-15

    Climate forecasts regarding the 21st century raise expectations in soil erosion growth mainly due to changes in heavy precipitation characteristics and ground cover in line with the adaptation of the crop growing season to future climatic conditions. The aim of this study initiated by the Federal Environmental Agency was, to examine the impacts of climate change on soil erosion by water in Germany using data calculated by the statistical climate model WETTREG. Soil erosion by water was estimated following an USLE approach implemented in ABAGFlux and TerraFlux with focus on the usage-based erosion potential in German agricultural areas. In the 2nd project phase the USLE R factor was recalculated for the recent (1971-2000) and future climate periods (2011-2040, 2041-2070, 2071-2100) using statistical methods such as the peak over threshold method. Furthermore the climate-induced change of the C-factor was analyzed with respect to changes of culture periods, ground cover and the monthly R factor. Scenarios regarding future percentage of conservation tillage systems as also the potential and usage-based soil erosion for these four climate periods have been modelled. The results underline a requirement to differentiate the view on temporal and spatial development of R factors and potential soil erosion. There are minor changes between 2011 and 2040 followed by an increased erosion hazard in western and north-western Germany after 2041 while eastern and southern Germany face a downward trend of R factors, derived using WETTREG data of a reference period 1971 to 2000. Between 2071 and 2100 potential soil erosion rises with R factors above the actual state due to more heavy rain falls nearly all over Germany. The resulting temporal offset of culture periods and the monthly distribution of the R factor cause rising C factors in all time periods as also increasing usage-based soil erosion hazard in Germany. This study shows that soil erosion exists in Germany. The problem

  8. Mapping monthly rainfall erosivity in Europe

    DEFF Research Database (Denmark)

    Ballabio, C; Meusburger, K; Klik, A

    2017-01-01

    Rainfall erosivity as a dynamic factor of soil loss by water erosion is modelled intra-annually for the first time at European scale. The development of Rainfall Erosivity Database at European Scale (REDES) and its 2015 update with the extension to monthly component allowed to develop monthly...... events. Consequently, spatio-temporal mapping of rainfall erosivity permits to identify the months and the areas with highest risk of soil loss where conservation measures should be applied in different seasons of the year....... to Eastern Europe. The maps also show a clear delineation of areas with different erosivity seasonal patterns, whose spatial outline was evidenced by cluster analysis. The monthly erosivity maps can be used to develop composite indicators that map both intra-annual variability and concentration of erosive...

  9. The Denudation Of Oahu, Hawaii USA By Ground And Surface Waters: The Effects Of Climate, Soil Thickness, And Water Contact Times On Ocean Island Erosion

    Science.gov (United States)

    Nelson, S. T.; Tingey, D. G.

    2011-12-01

    Access, size, basalt as the dominant bedrock, and climate variation (rainfall varies by 10x) make Oahu, Hawaii, USA an ideal locality for investigating chemical weathering driven denudation rates. New and compiled surface and groundwater solute data permit calculation of mass balances for solutes from Oahu, revealing that groundwater solute fluxes dominate surface water by a factor of 3 to 12, neglecting if biogenic silica removal by streams. Weathering reactions consistent with the observed mineralogy of Oahu soils and the calculated mineralogy of shield-forming tholeiitic basalts permit denudation rates to be partitioned between dissolved and suspended loads where long term erosion via streams and soil formation rates are assumed to be in a steady state. Aerially averaged denudation rates, indexed to the leaching of SiO2, vary from 0.016 to 0.063 m/ka, with about 70% of denudation due to dissolved fluxes. Thus, groundwater appears to be the single most important source of mass flux to the ocean from ocean islands. Dry regions of Oahu have distinctly lower denudation rates, and areas with thick soil profiles have suppressed solute loads in streams because laterites and subjacent saprolites have already been largely depleted in mobile elements. However, systematic differences also exist due to different contact times between groundwater and aquifer materials. The short, shallow circulation of stream base flows permits less extensive reaction with basalt resulting in lower solute loads even in areas where thick soils are largely absent. In addition to larger total water fluxes, deep groundwaters exhibit elevated solute loads across Oahu. Indexing denudation in basaltic terranes to dissolved SiO2, a minor component in seawater, rather than other solutes leads to improved estimates of weathering rates in ocean islands. Other approaches require correction for the atmospheric depositions of sea salts based on Cl- abundances in waters that are assumed to derive solely

  10. Soil erosion dynamics response to landscape pattern

    NARCIS (Netherlands)

    Ouyang, W.; Skidmore, A.K.; Hao, F.; Wang, T.

    2010-01-01

    Simulating soil erosion variation with a temporal land use database reveals long-term fluctuations in landscape patterns, as well as priority needs for soil erosion conservation. The application of a multi-year land use database in support of a Soil Water Assessment Tool (SWAT) led to an accurate

  11. Emission Facilities - Erosion & Sediment Control Facilities

    Data.gov (United States)

    NSGIC Education | GIS Inventory — An Erosion and Sediment Control Facility is a DEP primary facility type related to the Water Pollution Control program. The following sub-facility types related to...

  12. Soil erosion - a local and national problem

    Science.gov (United States)

    C.G. Bates; O.R. Zeasman

    1930-01-01

    The erosion of soils through the action of rain water and that from melting snow is almost universal in its occurrence. The gradual erosion and levelling of any country is inevitable, being a process which has gone on as long as there has been free water on the face of the earth. Nevertheless, this process is an extremely slow one where the landscape is naturally well...

  13. Surface erosion assessment using 137 Cs: examples from New Zealand

    OpenAIRE

    Basher, L. R.

    2000-01-01

    The 137Cs technique has provided the first quantitative, medium-term data on rates of soil redistribution by surface erosion on both cropland and rangeland in New Zealand. Use of the technique has demonstrated: high rates of soil redistribution by water erosion at two cropland sites under intensive vegetable production; a slow rate of net loss of soil by wind erosion associated with arable farming; a strong association between vegetation depletion and wind erosion on grazed rangeland. Re...

  14. Emergency wind erosion control

    Science.gov (United States)

    February through May is the critical time for wind erosion in Kansas, but wind erosion can happen any time when high winds occur on smooth, wide fields with low vegetation and poor soil structure. The most effective wind erosion control is to ensure a protective cover of residue or growing crop thro...

  15. Erosion and Errors

    NARCIS (Netherlands)

    Huisman, H.; Heeres, Glenn; Os, van Bertil; Derickx, Willem; Schoorl, J.M.

    2016-01-01

    Slope soil erosion is one of the main threats to archaeological sites. Several methods were applied to establish the erosion rates at archaeological sites. Digital elevation models (DEMs) from three different dates were used. We compared the elevations from these three models to estimate erosion. We

  16. Hidden bone erosions

    Directory of Open Access Journals (Sweden)

    F. Salaffi

    2011-09-01

    Full Text Available The aim of this pictorial essay was to demonstrate the diagnostic efficacy of high-resolution sonography in detecting bone erosions in a patient with rheumatoid arthritis. Standard X-Ray of the feet did not reveal clearly evident erosions. Ultrasonography was able to detect the presence of bone erosions of the metatarsal heads of both the first toes and of the V toe of the left foot. Because the appearance of bone erosions on radiographs of a patient with a recent onset arthritis indicates a poor prognosis, the possibility of demonstrating small hidden erosions at the level of the early targets of the disease is of relevant practical value.

  17. Effect of Integrated Water-Nutrient Management Strategies on Soil Erosion Mediated Nutrient Loss and Crop Productivity in Cabo Verde Drylands.

    Directory of Open Access Journals (Sweden)

    Isaurinda Baptista

    Full Text Available Soil erosion, runoff and related nutrient losses are a big risk for soil fertility in Cabo Verde drylands. In 2012, field trials were conducted in two agro-ecological zones to evaluate the effects of selected techniques of soil-water management combined with organic amendments (T1: compost/manure + soil surfactant; T2: compost/animal or green manure + pigeon-pea hedges + soil surfactant; T3: compost/animal or green manure + mulch + pigeon-pea hedges on nitrogen (N and phosphorus (P losses in eroded soil and runoff and on crop yields. Three treatments and one control (traditional practice were tested in field plots at three sites with a local maize variety and two types of beans. Runoff and eroded soil were collected after each erosive rain, quantified, and analysed for NO3-N and PO4-P concentrations. In all treatments runoff had higher concentrations of NO3-N (2.20-4.83 mg L-1 than of PO4-P (0.02-0.07 mg L-1, and the eroded soil had higher content of PO4-P (5.27-18.8 mg g-1 than of NO3-N (1.30-8.51 mg g-1. The control had significantly higher losses of both NO3-N (5.4, 4.4 and 19 kg ha-1 and PO4-P (0.2, 0.1 and 0.4 kg ha-1 than the other treatments. T3 reduced soil loss, runoff and nutrient losses to nearly a 100% while T1 and T2 reduced those losses from 43 to 88%. The losses of NO3-N and PO4-P were highly correlated with the amounts of runoff and eroded soil. Nutrient losses from the applied amendments were low (5.7% maximum, but the losses in the control could indicate long-term nutrient depletion in the soil (19 and 0.4 kg ha-1 of NO3-N and PO4-P, respectively. T1-T3 did not consistently increase crop yield or biomass in all three sites, but T1 increased both crop yield and biomass. We conclude that T3 (combining crop-residue mulch with organic amendment and runoff hedges is the best treatment for steep slope areas but, the pigeon-pea hedges need to be managed for higher maize yield. T1 (combining organic amendment with soil surfactant could

  18. Effect of Integrated Water-Nutrient Management Strategies on Soil Erosion Mediated Nutrient Loss and Crop Productivity in Cabo Verde Drylands.

    Science.gov (United States)

    Baptista, Isaurinda; Ritsema, Coen; Geissen, Violette

    2015-01-01

    Soil erosion, runoff and related nutrient losses are a big risk for soil fertility in Cabo Verde drylands. In 2012, field trials were conducted in two agro-ecological zones to evaluate the effects of selected techniques of soil-water management combined with organic amendments (T1: compost/manure + soil surfactant; T2: compost/animal or green manure + pigeon-pea hedges + soil surfactant; T3: compost/animal or green manure + mulch + pigeon-pea hedges) on nitrogen (N) and phosphorus (P) losses in eroded soil and runoff and on crop yields. Three treatments and one control (traditional practice) were tested in field plots at three sites with a local maize variety and two types of beans. Runoff and eroded soil were collected after each erosive rain, quantified, and analysed for NO3-N and PO4-P concentrations. In all treatments runoff had higher concentrations of NO3-N (2.20-4.83 mg L-1) than of PO4-P (0.02-0.07 mg L-1), and the eroded soil had higher content of PO4-P (5.27-18.8 mg g-1) than of NO3-N (1.30-8.51 mg g-1). The control had significantly higher losses of both NO3-N (5.4, 4.4 and 19 kg ha-1) and PO4-P (0.2, 0.1 and 0.4 kg ha-1) than the other treatments. T3 reduced soil loss, runoff and nutrient losses to nearly a 100% while T1 and T2 reduced those losses from 43 to 88%. The losses of NO3-N and PO4-P were highly correlated with the amounts of runoff and eroded soil. Nutrient losses from the applied amendments were low (5.7% maximum), but the losses in the control could indicate long-term nutrient depletion in the soil (19 and 0.4 kg ha-1 of NO3-N and PO4-P, respectively). T1-T3 did not consistently increase crop yield or biomass in all three sites, but T1 increased both crop yield and biomass. We conclude that T3 (combining crop-residue mulch with organic amendment and runoff hedges) is the best treatment for steep slope areas but, the pigeon-pea hedges need to be managed for higher maize yield. T1 (combining organic amendment with soil surfactant) could be a

  19. Effect of Integrated Water-Nutrient Management Strategies on Soil Erosion Mediated Nutrient Loss and Crop Productivity in Cabo Verde Drylands

    Science.gov (United States)

    Baptista, Isaurinda; Ritsema, Coen; Geissen, Violette

    2015-01-01

    Soil erosion, runoff and related nutrient losses are a big risk for soil fertility in Cabo Verde drylands. In 2012, field trials were conducted in two agro-ecological zones to evaluate the effects of selected techniques of soil-water management combined with organic amendments (T1: compost/manure + soil surfactant; T2: compost/animal or green manure + pigeon-pea hedges + soil surfactant; T3: compost/animal or green manure + mulch + pigeon-pea hedges) on nitrogen (N) and phosphorus (P) losses in eroded soil and runoff and on crop yields. Three treatments and one control (traditional practice) were tested in field plots at three sites with a local maize variety and two types of beans. Runoff and eroded soil were collected after each erosive rain, quantified, and analysed for NO3-N and PO4-P concentrations. In all treatments runoff had higher concentrations of NO3-N (2.20-4.83 mg L-1) than of PO4-P (0.02-0.07 mg L-1), and the eroded soil had higher content of PO4-P (5.27-18.8 mg g-1) than of NO3-N (1.30-8.51 mg g-1). The control had significantly higher losses of both NO3-N (5.4, 4.4 and 19 kg ha-1) and PO4-P (0.2, 0.1 and 0.4 kg ha-1) than the other treatments. T3 reduced soil loss, runoff and nutrient losses to nearly a 100% while T1 and T2 reduced those losses from 43 to 88%. The losses of NO3-N and PO4-P were highly correlated with the amounts of runoff and eroded soil. Nutrient losses from the applied amendments were low (5.7% maximum), but the losses in the control could indicate long-term nutrient depletion in the soil (19 and 0.4 kg ha-1 of NO3-N and PO4-P, respectively). T1-T3 did not consistently increase crop yield or biomass in all three sites, but T1 increased both crop yield and biomass. We conclude that T3 (combining crop-residue mulch with organic amendment and runoff hedges) is the best treatment for steep slope areas but, the pigeon-pea hedges need to be managed for higher maize yield. T1 (combining organic amendment with soil surfactant) could be a

  20. [Seasonal characteristics of soil respiration and affecting factors under typical vegetations in the water-wind erosion crisscross region of the Loess Plateau].

    Science.gov (United States)

    Xie, Hui-Hui; Fan, Jun; Qi, Li-Bin; Hao, Ming-De

    2010-12-01

    By the soil respiration system, the characteristics of soil respiration were investigated to explore the correlations between soil respiration and soil temperature, soil water and soil nutrient under different land use patterns in the water-wind erosion crisscross region of the Loess Plateau. The results indicated that the seasonal changing characteristics of soil respiration were distinguished significantly among different vegetations, and soil water content and temperature were the main influencing factors. Soil respiration seasonal changing ranges, such as bare land, crop land, Medicago sativa land, Caragana korshinskii land, abandoned wild grass land, Stipa bungeana land, wild grass land, degraded Medicago sativa land, sloping Medicago sativa land, sloping abandoned wild grass land, sloping crop land and terraced crop land, were 0.32-0.82, 0.41-2.83, 0.74-2.81, 0.76-3.07, 0.67-2.79, 0.51-2.12, 0.56-2.05, 0.59-1.66, 0.42-2.09, 0.31-1.86, 0.32-1.93 and 0.41-3.17 micromol x (m2 x s)(-1). Comparing seasonal changing magnitudes of soil respiration, crop land was the biggest (167% - 203%), abandoned wild grass land (117% -154%), Caragana korshinskii land (134%), Stipa bungeana land (129%), Medicago sativa land (119%-120%) and bare land (94%) followed crop land. The smallest was degraded Medicago sativa land (92%). Bare land and degraded Medicago sativa land had small seasonal variation during the study period. Monthly average values of soil carbon flux (soil respiration) of Medicago sativa land and Caragana korshinskii land were maximal, but the maximum values under crop land were observed in July and August. Besides Q10 of crop land was also maximal, which reached 1.86. There were significant correlations between soil respiration and soil organic matter and available K. Moreover, soil respiration was affected by soil organic matter and total nitrogen in July and August when the water and heat condition were plentiful, but soil ammonium nitrogen had negative impact

  1. Rainfall Erosivity in Europe

    DEFF Research Database (Denmark)

    Panagos, Panos; Ballabio, Cristiano; Borrelli, Pasquale

    2015-01-01

    Rainfall is one the main drivers of soil erosion. The erosive force of rainfall is expressed as rainfall erosivity. Rainfall erosivity considers the rainfall amount and intensity, and is most commonly expressed as the Rfactor in the USLE model and its revised version, RUSLE. At national...... and continental levels, the scarce availability of data obliges soil erosion modellers to estimate this factor based on rainfall data with only low temporal resolution (daily, monthly, annual averages). The purpose of this study is to assess rainfall erosivity in Europe in the form of the RUSLE R-factor, based....... Gaussian Process Regression (GPR) has been used to interpolate the R-factor station values to a European rainfall erosivity map at 1 km resolution. The covariates used for the R-factor interpolation were climatic data (total precipitation, seasonal precipitation, precipitation of driest/wettest months...

  2. Nutrient losses by water erosion Perdas de nutrientes na água da erosão hídrica

    Directory of Open Access Journals (Sweden)

    Ildegardis Bertol

    2003-01-01

    Full Text Available Water erosion causes soil degradation, which is closely related to nutrient losses either in, the soluble form or adsorbed to soil particles, depending mainly on the adopted soil management system. This study was carried out in São José do Cerrito, SC, Brazil, between March 2000 and June 2001. The objective was to quantify available nitrogen, phosphorus, potassium, calcium and magnesium losses in water erosion obtained with simulated rainfall in the following soil management systems: conventional tillage with no-crop (bare soil (BS, conventional tillage with soybean (CT, reduced tillage with soybean (RT, no tillage with soybean on a desiccated and burned natural pasture (DBNP, and no tillage with soybean on a desiccated natural pasture (DNP. A rotating boom rainfall simulator was used to perform three rainfall tests with constant intensity of 64 mm h-1 and sufficient duration to reach constant runoff rate, on a clayey-loam, well-structured Typic Hapludox, with an average slope of 0.18 m m-1. The first test was carried out five days before soybean emergence and the second and third at 30 and 60 days, respectively. The nutrient concentration in water and total losses of nitrogen, phosphorus, potassium, calcium and magnesium were higher under CT than in the other soil management systems.A erosão hídrica causa o empobrecimento dos solos, devido ao transporte de nutrientes, os quais são transportados tanto adsorvidos aos colóides do solo quanto solubilizados na água, podendo variar com o sistema de manejo solo. O trabalho foi conduzido em São José do Cerrito (SC, entre março de 2000 e junho de 2001, com o objetivo de quantificar as perdas de nitrogênio, fósforo, potássio, cálcio e magnésio na água da erosão hídrica sob chuva simulada, nos seguintes sistemas de manejo: aração+duas gradagens sem cultivo do solo (SSC, aração+duas gradagens com cultivo de soja (PCO, escarificação+uma gradagem com cultivo de soja (CMI, semeadura

  3. SPATIAL AND TEMPORAL MODELING OF WATER EROSION IN DYSTROPHIC RED LATOSOL (OXISOL USED FOR FARMING AND CATTLE RAISING ACTIVITIES IN A SUB-BASIN IN THE SOUTH OF MINAS GERAIS

    Directory of Open Access Journals (Sweden)

    Diogo Olivetti

    2015-02-01

    Full Text Available Water erosion is one of the most important soil degradation processes and it can be intensified by land use and vegetal covering changes. Thus, water erosion modeling studies associated to multi temporal analyses of land use are effective in assessing how changes in land cover affects sediment yield. Therefore, considering the modifications in the land use from 1986 to 2011, the aim of this study ranged to estimate water erosion rates and compare them to the soil loss tolerance (SLT limit in the Latosols (Oxisols at Ribeirão Caçús sub-basin, in the South of Minas Gerais State, Southeast Brazil, by means of the Revised Universal Soil Loss Equation (RUSLE in association with the geographic information system (GIS, and geostatistical techniques. So, for each year mapped, soil loss averages were compared by t test at 5% significance to assess the soil degradation stage. The results indicated that, in the period, the soil loss average rate was from 2.4 to 2.6 Mg ha-1 year-1 and the areas with soil loss above the limit of SLT were around 8.0%. The t test demonstrated there was no considerable difference among the soil loss averages (p = 0.18. In consequence, the area of degraded soils did not increase. Thus, the RUSLE model in GIS is a simple and useful tool to estimate the soil loss and help define soil conservation and recovery measures.

  4. Techniques for assessing water resource potentials in the developing countries: with emphasis on streamflow, erosion and sediment transport, water movement in unsaturated soils, ground water, and remote sensing in hydrologic applications

    Science.gov (United States)

    Taylor, George C.

    1971-01-01

    . Nuclear methodology in hydrologic applications is generally more complex than the conventional and hence requires a high level of technical expertise for effective use. Application of nuclear techniques to hydrologic problems in the developing countries is likely to be marginal for some years to come, owing to the higher costs involved and expertise required. Nuclear techniques, however, would seem to have particular promise in studies of water movement in unsaturated soils and of erosion and sedimentation where conventional techniques are inadequate, inefficient and in some cases costly. Remote sensing offers great promise for synoptic evaluations of water resources and hydrologic processes, including the transient phenomena of the hydrologic cycle. Remote sensing is not, however, a panacea for deficiencies in hydrologic data programs in the developing countries. Rather it is a means for extending and augmenting on-the-ground observations ans surveys (ground truth) to evaluated water resources and hydrologic processes on a regionall or even continental scale. With respect to economic growth goals in developing countries, there are few identifiable gaps in existing hydrologic instrumentation and methodology insofar as appraisal, development and management of available water resources are concerned. What is needed is acceleration of institutional development and professional motivation toward more effective use of existing and proven methodology. Moreover, much sophisticated methodology can be applied effectively in the developing countries only when adequate levels of indigenous scientific skills have been reached and supportive institutional frameworks are evolved to viability.

  5. Potential impacts of climate change on soil erosion vulnerability across the conterminous United States

    Science.gov (United States)

    C. Segura; G. Sun; S. McNulty; Y. Zhang

    2014-01-01

    Rainfall runoff erosivity (R) is one key climate factor that controls water erosion. Quantifying the effects of climate change-induced erosivity change is important for identifying critical regions prone to soil erosion under a changing environment. In this study we first evaluate the changes of R from 1970 to 2090 across the United States under nine climate conditions...

  6. Rainfall erosivity in New Zealand

    Science.gov (United States)

    Klik, Andreas; Haas, Kathrin; Dvorackova, Anna; Fuller, Ian

    2014-05-01

    Rainfall and its kinetic energy expressed by the rainfall erosivity is the main driver of soil erosion processes by water. The Rainfall-Runoff Erosivity Factor (R) of the Revised Universal Soil Loss Equation is one oft he most widely used parameters describing rainfall erosivity. This factor includes the cumulative effects of the many moderate-sized storms as well as the effects oft he occasional severe ones: R quantifies the effect of raindrop impact and reflects the amopunt and rate of runoff associated with the rain. New Zealand is geologically young and not comparable with any other country in the world. Inordinately high rainfall and strong prevailing winds are New Zealand's dominant climatic features. Annual rainfall up to 15000 mm, steep slopes, small catchments and earthquakes are the perfect basis for a high rate of natural and accelerated erosion. Due to the multifacted landscape of New Zealand its location as island between the Pacific and the Tasmanian Sea there is a high gradient in precipitation between North and South Island as well as between West and East Coast. The objective of this study was to determine the R-factor for the different climatic regions in New Zealand, in order to create a rainfall erosivity map. We used rainfall data (breakpoint data in 10-min intervals) from 34 gauging stations for the calcuation of the rainfall erosivity. 15 stations were located on the North Island and 19 stations on the South Island. From these stations, a total of 397 station years with 12710 rainstorms were analyzed. The kinetic energy for each rainfall event was calculated based on the equation by Brown and Foster (1987), using the breakpoint precipitation data for each storm. On average, a mean annual precipitation of 1357 mm was obtained from the 15 observed stations on the North Island. Rainfall distribution throughout the year is relatively even with 22-24% of annual rainfall occurring in spring , fall and winter and 31% in summer. On the South Island

  7. Soil erosion and the global carbon budget.

    Science.gov (United States)

    Lal, R

    2003-07-01

    Soil erosion is the most widespread form of soil degradation. Land area globally affected by erosion is 1094 million ha (Mha) by water erosion, of which 751 Mha is severely affected, and 549 Mha by wind erosion, of which 296 Mha is severely affected. Whereas the effects of erosion on productivity and non-point source pollution are widely recognized, those on the C dynamics and attendant emission of greenhouse gases (GHGs) are not. Despite its global significance, erosion-induced carbon (C) emission into the atmosphere remains misunderstood and an unquantified component of the global carbon budget. Soil erosion is a four-stage process involving detachment, breakdown, transport/redistribution and deposition of sediments. The soil organic carbon (SOC) pool is influenced during all four stages. Being a selective process, erosion preferentially removes the light organic fraction of a low density of erosion causes a severe depletion of the SOC pool on eroded compared with uneroded or slightly eroded soils. In addition, the SOC redistributed over the landscape or deposited in depressional sites may be prone to mineralization because of breakdown of aggregates leading to exposure of hitherto encapsulated C to microbial processes among other reasons. Depending on the delivery ratio or the fraction of the sediment delivered to the river system, gross erosion by water may be 75 billion Mg, of which 15-20 billion Mg are transported by the rivers into the aquatic ecosystems and eventually into the ocean. The amount of total C displaced by erosion on the earth, assuming a delivery ratio of 10% and SOC content of 2-3%, may be 4.0-6.0 Pg/year. With 20% emission due to mineralization of the displaced C, erosion-induced emission may be 0.8-1.2 Pg C/year on the earth. Thus, soil erosion has a strong impact on the global C cycle and this component must be considered while assessing the global C budget. Adoption of conservation-effective measures may reduce the risks of C emission and

  8. Protection from erosion following wildfire

    Science.gov (United States)

    Peter R. Robichaud; William J. Elliot

    2006-01-01

    Erosion in the first year after a wildfire can be up to three orders of magnitude greater than the erosion from undisturbed forests. To mitigate potential postfire erosion, various erosion control treatments are applied on highly erodible areas with downstream resources in need of protection. Because postfire erosion rates generally decline by an order of magnitude for...

  9. Saliva and dental erosion

    Directory of Open Access Journals (Sweden)

    Marília Afonso Rabelo Buzalaf

    2012-10-01

    Full Text Available Dental erosion is a multifactorial condition. The consideration of chemical, biological and behavioral factors is fundamental for its prevention and therapy. Among the biological factors, saliva is one of the most important parameters in the protection against erosive wear. Objective: This review discusses the role of salivary factors on the development of dental erosion. Material and Methods: A search was undertaken on MeDLINe website for papers from 1969 to 2010. The keywords used in the research were "saliva", "acquired pellicle", "salivary flow", "salivary buffering capacity" and "dental erosion". Inclusion of studies, data extraction and quality assessment were undertaken independently and in duplicate by two members of the review team. Disagreements were solved by discussion and consensus or by a third party. Results: Several characteristics and properties of saliva play an important role in dental erosion. Salivary clearance gradually eliminates the acids through swallowing and saliva presents buffering capacity causing neutralization and buffering of dietary acids. Salivary flow allows dilution of the acids. In addition, saliva is supersaturated with respect to tooth mineral, providing calcium, phosphate and fluoride necessary for remineralization after an erosive challenge. Furthermore, many proteins present in saliva and acquired pellicle play an important role in dental erosion. Conclusions: Saliva is the most important biological factor affecting the progression of dental erosion. Knowledge of its components and properties involved in this protective role can drive the development of preventive measures targeting to enhance its known beneficial effects.

  10. Saliva and dental erosion

    Science.gov (United States)

    BUZALAF, Marília Afonso Rabelo; HANNAS, Angélicas Reis; KATO, Melissa Thiemi

    2012-01-01

    Dental erosion is a multifactorial condition. The consideration of chemical, biological and behavioral factors is fundamental for its prevention and therapy. Among the biological factors, saliva is one of the most important parameters in the protection against erosive wear. Objective This review discusses the role of salivary factors on the development of dental erosion. Material and Methods A search was undertaken on MEDLINE website for papers from 1969 to 2010. The keywords used in the research were "saliva", "acquired pellicle", "salivary flow", "salivary buffering capacity" and "dental erosion". Inclusion of studies, data extraction and quality assessment were undertaken independently and in duplicate by two members of the review team. Disagreements were solved by discussion and consensus or by a third party. Results Several characteristics and properties of saliva play an important role in dental erosion. Salivary clearance gradually eliminates the acids through swallowing and saliva presents buffering capacity causing neutralization and buffering of dietary acids. Salivary flow allows dilution of the acids. In addition, saliva is supersaturated with respect to tooth mineral, providing calcium, phosphate and fluoride necessary for remineralization after an erosive challenge. Furthermore, many proteins present in saliva and acquired pellicle play an important role in dental erosion. Conclusions Saliva is the most important biological factor affecting the progression of dental erosion. Knowledge of its components and properties involved in this protective role can drive the development of preventive measures targeting to enhance its known beneficial effects. PMID:23138733

  11. Erosion Negril Beach

    NARCIS (Netherlands)

    Ten Ham, D.; Henrotte, J.; Kraaijeveld, R.; Milosevic, M.; Smit, P.

    2006-01-01

    The ongoing erosion of the Negril Beach has become worse the past decade. In most places along the coast line, the beach will be gone in approximately 10 years. This will result in a major decrease of incomes that are made by the local tourist sector. To prevent the erosion this study has been

  12. Mapping monthly rainfall erosivity in Europe.

    Science.gov (United States)

    Ballabio, Cristiano; Borrelli, Pasquale; Spinoni, Jonathan; Meusburger, Katrin; Michaelides, Silas; Beguería, Santiago; Klik, Andreas; Petan, Sašo; Janeček, Miloslav; Olsen, Preben; Aalto, Juha; Lakatos, Mónika; Rymszewicz, Anna; Dumitrescu, Alexandru; Tadić, Melita Perčec; Diodato, Nazzareno; Kostalova, Julia; Rousseva, Svetla; Banasik, Kazimierz; Alewell, Christine; Panagos, Panos

    2017-02-01

    Rainfall erosivity as a dynamic factor of soil loss by water erosion is modelled intra-annually for the first time at European scale. The development of Rainfall Erosivity Database at European Scale (REDES) and its 2015 update with the extension to monthly component allowed to develop monthly and seasonal R-factor maps and assess rainfall erosivity both spatially and temporally. During winter months, significant rainfall erosivity is present only in part of the Mediterranean countries. A sudden increase of erosivity occurs in major part of European Union (except Mediterranean basin, western part of Britain and Ireland) in May and the highest values are registered during summer months. Starting from September, R-factor has a decreasing trend. The mean rainfall erosivity in summer is almost 4 times higher (315MJmmha-1h-1) compared to winter (87MJmmha-1h-1). The Cubist model has been selected among various statistical models to perform the spatial interpolation due to its excellent performance, ability to model non-linearity and interpretability. The monthly prediction is an order more difficult than the annual one as it is limited by the number of covariates and, for consistency, the sum of all months has to be close to annual erosivity. The performance of the Cubist models proved to be generally high, resulting in R2 values between 0.40 and 0.64 in cross-validation. The obtained months show an increasing trend of erosivity occurring from winter to summer starting from western to Eastern Europe. The maps also show a clear delineation of areas with different erosivity seasonal patterns, whose spatial outline was evidenced by cluster analysis. The monthly erosivity maps can be used to develop composite indicators that map both intra-annual variability and concentration of erosive events. Consequently, spatio-temporal mapping of rainfall erosivity permits to identify the months and the areas with highest risk of soil loss where conservation measures should be applied in

  13. Study on the standard of soil erosion gradation based on erosive daily rainfall

    Science.gov (United States)

    Li, Gang; Ye, Suigao; Shen, Zhaowei; Lu, Fangchun; Zhang, Jinjuan

    2017-11-01

    This paper took Yuyao city as the research area. the daily rainfall data of 30-year was collected from the typical rainfall station. And the daily rainfall power function model was used to calculate the rainfall erosivity. The weight that the rainfall erosivity of the rainfall less than 30mm accounted for the total annual rainfall erosivity was calculated and analyzed. A method for soil erosion intensity gradation based on daily rainfall was proposed. At the same time, according to People’s Republic of China water conservancy industry standard “the standards for classification and gradation of soil erosion”, the weight value was used to establish the gradation standard of soil erosion intensity. The daily soil loss tolerance was 7 t/km2 calculated by this method.

  14. Potential for monitoring soil erosion features and soil erosion modeling components from remotely sensed data

    Science.gov (United States)

    Langran, K. J.

    1983-01-01

    Accurate estimates of soil erosion and its effects on soil productivity are essential in agricultural decision making and planning from the field scale to the national level. Erosion models have been primarily developed for designing erosion control systems, predicting sediment yield for reservoir design, predicting sediment transport, and simulating water quality. New models proposed are more comprehensive in that the necessary components (hydrology, erosion-sedimentation, nutrient cycling, tillage, etc.) are linked in a model appropriate for studying the erosion-productivity problem. Recent developments in remote sensing systems, such as Landsat Thematic Mapper, Shuttle Imaging Radar (SIR-B), etc., can contribute significantly to the future development and operational use of these models.

  15. Pressure and velocity dependence of flow-type cavitation erosion

    CSIR Research Space (South Africa)

    Auret, JG

    1993-12-01

    Full Text Available for rotating disc test rig Parameter Static water pressure Water temperature Sample velocity Air content of water Water flow rate Water quality Range 0.1-2 MPa Ambient to 100 ?C ~40-60 m s-l Deaerated to supersaturated O-30 1... ship?s screw), as opposed to vibratory cavitation erosion. For flow-type cavitation erosion, well-defined rela- tions exist between the flow velocity and liquid pressure, and the amount of cavitation and erosion damage...

  16. The importance of erosion for debris flow runout modelling from applications to the Swiss Alps

    OpenAIRE

    Frank, F.; McArdell, B. W.; Huggel, C.; A. Vieli

    2015-01-01

    This study describes an investigation of channel-bed erosion of sediment by debris flows. An erosion model, developed using field data from debris flows at the Illgraben catchment, Switzerland, was incorporated into the existing RAMMS debris-flow model, which solves the 2-D shallow-water equations for granular flows. In the erosion model, the relationship between maximum shear stress and measured erosion is used to determine the maximum potential erosion depth. Additionally,...

  17. Soil erosion modelling nowadays: insights of a young scientist

    Science.gov (United States)

    López-Vicente, Manuel; Kirkby, Mike

    2013-04-01

    Soil erosion models allow mapping and quantifying rates of runoff depth and soil redistribution in a wide variety of environments for different land uses and climatic scenarios. Runoff generation, soil detachment, sediment delivery and river dynamic are non-linear processes that depend on many factors, and thus the development of accurate and broad models has being always a difficult task. Taking in mind this complexity, predicting models have evolved from the first empirical equations (1930's) to the current ambitious and GIS-based models. The first attempts were developed for small areas like the studies of Mockus (1949) and Andrews (1954) that constituted the basis of the runoff Curve Number (SCS-CN). The research of Wischmeier and Smith (1958 and 1978) in plots about the relationship between rainfall energy, soil erodibility and soil loss as well as the development of the Universal Soil Loss Equation became the RUSLE model (Renard et al., 1991) that has been one of the most applied models of rill and interrill erosion. A recent version of RUSLE is the WATEM/SEDEM (Van Rompaey et al., 2001) model that predicts spatially distributed rates of soil loss and deposition at catchment scale and also estimates tillage erosion. Other models simulated not only processes of surface runoff and soil erosion but processes of nutrients, pollutants and sediment delivery, such as CREAMS (Kinsel, 1980) and AGNPS (Young et al., 1987). The assistance of GIS techniques in the 1990's was a milestone that let scientists create advanced models such as the dynamic LISEM (De Roo et al., 1995) and the hydrological STREAM (Cerdan et al., 2002) models. In some cases the current models can be downloaded as executable files: the empirical RUSLE2 (Foster et al., 2000), the process-based WEPP (Adams et al., 2012) and DR2 (López-Vicente and Navas, 2012), the complex river basin SWAT (Arnold et al., 1998) and TETIS (Francés et al., 2007) and the reduced-complexity SedNet (Prosser et al., 2001

  18. An Experimental Simulation Method of Erosion Process on Gully Erosion in Loess Plateau in China

    Science.gov (United States)

    Gao, Jianen; Zhang, Yuanxing

    2017-04-01

    In view of simulation difficultment of the field gully erosion process because of complex of rainfall runoff erosion mechanism and gully geometry a design means and experimentation technology and its verification test were given based on similarity theory and hydrodynamic principles. The basic ideas was that the erosion process of the field erosion gully was forecast by constructing similar model. The model and antetype should be in obedience to the same physical equations of rainfall, runoff, erosion, sediment transport, bed deformation and Soil water transport. The geometric, kinematical and dynamic similarity must be obeyed for these models. The primary similarity scale relation expressions were the ones of the geometric, rainfall, flow, erosion sediment transport and soil water movement similarity etc. The similarity of the hydraulic boundary was the necessary and sufficient condition between the model and the prototype. The gully prototype is one of Majiagou of Ansai county of Yanan City of Shaanxi Province in China. Its location is 36°53'55.75"N and 109°13'39.08"E. The model experiment wan carried out in State Key Laboratory of Soil Erosion and Dry land Farming On the Loess Plateau in Institute of Soil and Water Conservation of Northwest A&F University. First soil was selected by starting velocity similar. Second, the normal and scale 10 experiment model was built under complying with the similarities of geometric, rainfall, flow, erosion production sediment transport and bed deformation etc. The model hydraulic boundary from the prototype was the factor of the test process of rainfall. The experiment results indicated that the extreme rainstorm gully erosion process of the prototype could be reappeared. The equivalent rainfall process of gully prototype were that the rainfall intensity was 1.25 mm/min and the lasting time was 508 min and precipitation was 636mmn. Both the erosion amount and the erosion gully topography of the scale model were successfully

  19. Interdigital erosions: Tinea pedis?

    National Research Council Canada - National Science Library

    Orgaz-Molina, Jacinto; Orgaz-Molina, Maria Carmen; Cotugno, Marilena; Arias-Santiago, Salvador

    2012-01-01

    Interdigital erosions are frequently due to tinea pedis. However, other infectious conditions, such as candidiasis, erythrasma or bacterial infections, can generate lesions that cannot be differentiated at the clinical level...

  20. When erosion ruins the chronology

    Science.gov (United States)

    Wolters, Steffen; Enters, Dirk; Blume, Katharina; Lücke, Andreas

    2016-04-01

    Human land-use has considerably shaped the landscape of north-western Germany over the past millennia. Deforestation and agriculture created a predominantly open scenery preserved until today with only a few remnants of former landscape elements such as woodlands, peat bogs, heath lands and lakes. Here we present a multi-proxy approach including sedimentological and geochemical parameters (e. g. element concentrations and stable isotopes) as well as biological proxies (pollen, macro fossils and diatoms) combined with an archaeological site analysis to investigate the effects of prehistoric land-use on lake systems and their catchment areas with a special focus on changes of the water quality, e. g. eutrophication and acidification and its natural regeneration during phases of weaker land-use impact. The study reveals a millenia-long history of erosion processes caused by successive selective woodland clearances starting in Neolithic Times. The geochemical evidence of soil erosion is recorded by distinct peaks of the terrigenic elements K and Ti. However, due to (1) the low sensitivy of the XRF scanner for Si and (2) the prevalence of diatom related biogenic silicon XRF-scanning of highly organic lake sediments fails to reflect the actual sand input caused by erosion. Particularly single quartz grains are not detected in the organic sediment matrix. Therefore we make successful use of mineral grain analysis which previously has only been applied to record aeolian input in bogs. K and Ti concentrations are not correlated with the content of mineral grains which suggest two different erosion processes. Our efforts to construct robust age-depth relationships based on AMS 14C-dates of terrestrial plant macrofossils reveal a specific dating issue of northwest German lakes. Especially in younger sediments we observe 14C-dates which are on the one hand too old and on the other hand among themselves roughly contemporaneous. We explain this feature with the extensive bog

  1. Measurement of erosion: Is it possible?

    NARCIS (Netherlands)

    Stroosnijder, L.

    2005-01-01

    Reasons for erosion measurements are: (1) to determine the environmental impact of erosion and conservation practices, (2) scientific erosion research; (3) development and evaluation of erosion control technology; (4) development of erosion prediction technology and (5) allocation of conservation

  2. PENGARUH TINDAKAN KONSERVASI TANAH TERHADAP ALIRAN PERMUKAAN, EROSI, KEHILANGAN HARA DAN PENGHASILAN PADA USAHA TANI KENTANG DAN KUBIS (Effect of Coil and Water Conservation Practices on Runoff, Erosion, Nutrient Loss and Farmer Income of Potato

    Directory of Open Access Journals (Sweden)

    Umi Baroroh Lili Utami

    2001-08-01

    ekonomi, adalah perlakuan Po, sedangkan pada tanaman kubis adalah perlakuan P3.   ABSTRACT Erosion rate at Dieng Plateau, Central Java, is high because vegetable is the dominant crop, and in general the farmer never applied adequate soil and water conservation practices (SWCP/ The research was carried to assess the suitable soil conservation practices in order to reduce runoff, erosion nutrient losses and to increase the income as potato (Solanum tuberosum L and cabbage crop (Brassica oleracea L farmers. The erosion and runoff data were obtained by measuring the actual runoff and erosion for each rainfall event during February-May 2000 period. Measurement of the actual erosion and runoff were conducted on erosion plot of 10x2. The expoiment was done in a Randomized Complete Block Design (RCBD with two factors. The first factor was the crop, that is the potato (C1 and cabbage (C2. The second factor was the technical soil conservation, that is, cross contour ridging (P1 as control treatment, contour ridging and terrace-ridging that was planted with citronella (P2, the contour ridging with the much of lemograss (P3, and the contour ridging covered with black silver plastic sheet (P4. The result of the research on the potato crop showed that the P2, P3 and P4 treatments could effectively decrease erosion. The P2 and P4 treatments were able to increase the farmers income, however P3 decreased the farmer income. On the cabbage crop, the effective treatment which decreased erosion was P3. The P2, P3 and P4 treatments increased the farmers income

  3. Advances in wind erosion modelling in Europe

    Science.gov (United States)

    Borrelli, Pasquale; Lugato, Emanuele; Alewell, Christine; Montanarella, Luca; Panagos, Panos

    2017-04-01

    Soil erosion by wind is a serious environmental problem often resulting in severe forms of soil degradation. Wind erosion is also a phenomenon relevant for Europe, although this land degradation process has been overlooked until very recently. The state-of-the-art literature presents wind erosion as a process that locally affects the semi-arid areas of the Mediterranean region as well as the temperate climate areas of the northern European countries. Actual observations, field measurements and modelling assessments, however, are all extremely limited and highly unequally distributed across Europe. As a result, we currently lack comprehensive understanding about where and when wind erosion occurs in Europe, and the intensity of erosion that poses a threat to agricultural productivity. Today's challenge is to integrate the insights of local experiments and field-scale models into a new generation of large-scale wind erosion models. While naturally being less accurate than field-scale models, these large-scale modelling approaches still provide essential knowledge about where and when wind erosion occurs and can disclose the level of risk for agricultural productivity in specific areas. Here, we present a geographic information system (GIS) version of the RWEQ (named GIS-RWEQ) to quantitatively assess soil loss by wind over large study areas (Land Degradation & Development, DOI: 10.1002/ldr.2588). The model designed to predict the daily soil loss potential at a ca. 1 km2 spatial resolution shows high consistency with local measurements reported in literature. The average soil loss predicted by GIS-RWEQ for the European arable land totals 62 million Mg yr-1, with an average area-specific soil loss of 0.53 Mg yr-1. The JRC model RUSLE2015, for the same area estimates 295 million Mg yr-1 of soil loss due to water erosion. Notably, soil loss by wind erosion in the European arable land could be as high as 20% of water erosion, even though the areas affected are mainly

  4. Processes and Causes of Accelerated Soil Erosion on Cultivated ...

    African Journals Online (AJOL)

    The processes and causes of accelerated erosion on cultivated fields in the South Welo zone of Ethiopia were assessed on the basis of information collected from field surveys, group discussions and secondary sources. The findings suggest that soil erosion by water on cultivated slopes in the zone is currently proceeding ...

  5. Thresholds of gully erosion in the coastal plains sands of ...

    African Journals Online (AJOL)

    The concept of geomorphic threshold as applied in gully erosion studies assumes that water erosion occurs when the combined power of the rainfall energy and overland flow exceeds the resistance of surface materials to detachment and entrainment. This line of reasoning presupposes that certain environmental factors ...

  6. Modeling soil erosion and transport on forest landscape

    Science.gov (United States)

    Ge Sun; Steven G McNulty

    1998-01-01

    Century-long studies on the impacts of forest management in North America suggest sediment can cause major reduction on stream water quality. Soil erosion patterns in forest watersheds are patchy and heterogeneous. Therefore, patterns of soil erosion are difficult to model and predict. The objective of this study is to develop a user friendly management tool for land...

  7. understanding the mechanism of soil erosion from outdoor model ...

    African Journals Online (AJOL)

    Dr Obe

    rain, erosion by overland flow is of common occurrence. This is particularly true of three belts in the southeastern part of Nigeria, Fig. 1. Severe gully erosion of undeveloped and road shoulders is a threat to agricultural and transportation progress. This phenomenon arises from the lack of proper control of storm water on the.

  8. Bentonite erosion. Laboratory studies

    Energy Technology Data Exchange (ETDEWEB)

    Jansson, Mats (Div. of Nuclear Chemistry, Royal Inst. of Technology, Stockholm (Sweden), School of Chemical Science and Engineering)

    2009-11-15

    This report covers the laboratory studies that have been performed at Nuclear Chemistry, KTH in the project 'Bentonite Erosion'. Many of the experiments in this report were performed to support the work of the modelling group and were often relatively simple. One of the experiment series was performed to see the impact of gravity and concentration of mono- and di-valent cations. A clay suspension was prepared in a test tube. A net was placed in contact with the suspension, the test tube was filled with solutions of different concentrations and the system was left overnight to settle. The tube was then turned upside down and the behaviour was visually observed. Either the clay suspension fell through the net or stayed on top. By using this method surprisingly sharp determinations of the Critical Coagulation (Flocculation) Concentration (CCC/CFC) could be made. The CCC/CFC of Ca2+ was for sodium montmorillonite determined to be between 1 and 2 mM. An artificial fracture was manufactured in order to simulate the real case scenario. The set-up was two Plexiglas slabs separated by 1 mm thick spacers with a bentonite container at one side of the fracture. Water was pumped with a very low flow rate perpendicular to bentonite container and the water exiting the fracture was sampled and analyzed for colloid content. The bentonite used was treated in different ways. In the first experiment a relatively montmorillonite rich clay was used while in the second bentonite where only the readily soluble minerals had been removed was used. Since Plexiglas was used it was possible to visually observe the bentonite dispersing into the fracture. After the compacted bentonite (1,000 kg/m3) had been water saturated the clay had expanded some 12 mm out into the fracture. As the experiment progressed the clay expanded more out into the fracture and seemed to fractionate in two different phases with less material in the outmost phase. A dark rim which was later analyzed to contain

  9. Magnetite Nanoparticles Prepared By Spark Erosion

    Directory of Open Access Journals (Sweden)

    Maiorov M.

    2016-08-01

    Full Text Available In the present research, we study a possibility of using the electric spark erosion method as an alternative to the method of chemical co-precipitation for preparation of magnetic nanoparticles. Initiation of high frequency electric discharge between coarse iron particles under a layer of distilled water allows obtaining pure magnetite nanoparticles.

  10. Erosion and lateral surface processes 2432

    Science.gov (United States)

    : Erosion can cause serious agricultural and environmental hazards. It can generate severe damage to the landscape, lead to significant loss of agricultural land and consequently to reduction in agricultural productivity, induce surface water pollution due to the transport of sediments and suspende...

  11. Erosivity, surface runoff, and soil erosion estimation using GIS-coupled runoff-erosion model in the Mamuaba catchment, Brazil.

    Science.gov (United States)

    Marques da Silva, Richarde; Guimarães Santos, Celso Augusto; Carneiro de Lima Silva, Valeriano; Pereira e Silva, Leonardo

    2013-11-01

    This study evaluates erosivity, surface runoff generation, and soil erosion rates for Mamuaba catchment, sub-catchment of Gramame River basin (Brazil) by using the ArcView Soil and Water Assessment Tool (AvSWAT) model. Calibration and validation of the model was performed on monthly basis, and it could simulate surface runoff and soil erosion to a good level of accuracy. Daily rainfall data between 1969 and 1989 from six rain gauges were used, and the monthly rainfall erosivity of each station was computed for all the studied years. In order to evaluate the calibration and validation of the model, monthly runoff data between January 1978 and April 1982 from one runoff gauge were used as well. The estimated soil loss rates were also realistic when compared to what can be observed in the field and to results from previous studies around of catchment. The long-term average soil loss was estimated at 9.4 t ha(-1) year(-1); most of the area of the catchment (60%) was predicted to suffer from a low- to moderate-erosion risk (soil erosion was estimated to exceed > 12 t ha(-1) year(-1). Expectedly, estimated soil loss was significantly correlated with measured rainfall and simulated surface runoff. Based on the estimated soil loss rates, the catchment was divided into four priority categories (low, moderate, high and very high) for conservation intervention. The study demonstrates that the AvSWAT model provides a useful tool for soil erosion assessment from catchments and facilitates the planning for a sustainable land management in northeastern Brazil.

  12. Erosive Lichen Planus.

    Science.gov (United States)

    Mauskar, Melissa

    2017-09-01

    Lichen planus is an inflammatory mucocutaneous condition with a myriad of clinical manifestations. There are 3 forms of lichen planus that effect the vulva: papulosquamous, hypertrophic, and erosive. Erosive lichen planus can progress to vulvar scaring, vaginal stenosis, and squamous cell carcinoma; these long-term sequelae cause sexual distress, depression, and decreased quality of life for patients. Diagnosis is often delayed because of patient embarrassment or clinician misdiagnosis. Early recognition and treatment is essential to decreasing the morbidity of this condition. Multimodal treatment, along with a multidisciplinary approach, will improve outcomes and further clinical advances in studying this condition. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Clinical studies of dental erosion and erosive wear

    National Research Council Canada - National Science Library

    Huysmans, M.C.D.N.J.M; Chew, H.P; Ellwood, R.P

    2011-01-01

    We define erosion as a partial demineralisation of enamel or dentine by intrinsic or extrinsic acids and erosive tooth wear as the accelerated loss of dental hard tissue through the combined effect...

  14. An integrated assessment of soil erosion dynamics with special emphasis on gully erosion: Case studies from South Africa and Iran

    Science.gov (United States)

    Maerker, Michael; Sommer, Christian; Zakerinejad, Reza; Cama, Elena

    2017-04-01

    Soil erosion by water is a significant problem in arid and semi arid areas of large parts of Iran. Water erosion is one of the most effective phenomena that leads to decreasing soil productivity and pollution of water resources. Especially in semiarid areas like in the Mazayjan watershed in the Southwestern Fars province as well as in the Mkomazi catchment in Kwa Zulu Natal, South Africa, gully erosion contributes to the sediment dynamics in a significant way. Consequently, the intention of this research is to identify the different types of soil erosion processes acting in the area with a stochastic approach and to assess the process dynamics in an integrative way. Therefore, we applied GIS, and satellite image analysis techniques to derive input information for the numeric models. For sheet and rill erosion the Unit Stream Power-based Erosion Deposition Model (USPED) was utilized. The spatial distribution of gully erosion was assessed using a statistical approach which used three variables (stream power index, slope, and flow accumulation) to predict the spatial distribution of gullies in the study area. The eroded gully volumes were estimated for a multiple years period by fieldwork and Google Earth high resolution images as well as with structure for motion algorithm. Finally, the gully retreat rates were integrated into the USPED model. The results show that the integration of the SPI approach to quantify gully erosion with the USPED model is a suitable method to qualitatively and quantitatively assess water erosion processes in data scarce areas. The application of GIS and stochastic model approaches to spatialize the USPED model input yield valuable results for the prediction of soil erosion in the test areas. The results of this research help to develop an appropriate management of soil and water resources in the study areas.

  15. Clinical studies of dental erosion and erosive wear

    NARCIS (Netherlands)

    Huysmans, M.C.D.N.J.M.; Chew, H.P.; Ellwood, R.P.

    2011-01-01

    We define erosion as a partial demineralisation of enamel or dentine by intrinsic or extrinsic acids and erosive tooth wear as the accelerated loss of dental hard tissue through the combined effect of erosion and mechanical wear (abrasion and attrition) on the tooth surface. Most experts believe

  16. Controlled ultrasonic tissue erosion

    Science.gov (United States)

    Cain, Charles

    2003-04-01

    Controlled ultrasonic tissue erosion has many clinical applications, including the placement of very precise sharply defined perforations in biological interfaces and membranes with focused ultrasound. With carefully chosen acoustic parameters, tissue can be rapidly eroded away at a constant etching rate. The maximum erosion rate for minimal propagated energy is obtained by using very short high intensity pulses. The etching rate is higher with shorter pulse durations. For short pulses less than 10 cycles of the drive frequency, an optimum pulse repetition rate exists which maximizes the etching rate. Higher gas saturation in the surrounding medium reduces the etching rate and reduces the spatial sharpness of the holes produced. Most of the erosion appears to be produced in the first several cycles of the therapy pulse. For example, a series of short (about 3 cycles) focused pulses of 2100 W/cm2 (Isppa) at 788 kHz can erode a very well defined 2 mm diameter hole in a 1 mm thick sample of fresh pork atrial posterior wall in about 1 min at the optimum pulse repetition rate (about 18 kHz). Controlled ultrasonic tissue erosion may provide an effective image guided noninvasive tool in treatment of neonatal patients with hypoplastic left heart syndrome. Without the mixing of oxygenated blood across perforations placed in the atrial septum, these infants do not survive.

  17. Soil Erosion: Advanced Crop and Soil Science. A Course of Study.

    Science.gov (United States)

    Miller, Larry E.

    The course of study represents the last of six modules in advanced crop and soil science and introduces the agriculture student to the topic of soil erosion. Upon completion of the two day lesson, the student will be able to: (1) define conservation, (2) understand how erosion takes place, and (3) list ways of controlling wind and water erosion.…

  18. Modelling catchment-scale erosion patterns in the East African Highlands

    NARCIS (Netherlands)

    Vigiak, O.; Okoba, B.O.; Sterk, G.; Groenenberg, S.

    2005-01-01

    Prompt location of areas exposed to high erosion is of the utmost importance for soil and water conservation planning. Erosion models can be useful tools to locate sources of sediment and areas of deposition within a catchment, but the reliability of model predictions of spatial patterns of erosion

  19. Categorization of erosion control matting.

    Science.gov (United States)

    2012-05-29

    Erosion control is a critical aspect of any Georgia Department of Transportation (GDOT) : construction project, with the extreme negative impacts of high sediment loads in natural : waterways having been well documented. A variety of erosion control ...

  20. Soil erosion assessment on hillslope of GCE using RUSLE model

    Indian Academy of Sciences (India)

    61

    Wischmeier and Smith. 1978b), Water Erosion Prediction Project ...... cover (%). Wischmeier and. Smith (1978) C factor Table. Other literature sources: (Bubenzer 1980; ECTC. 2003; Israelsen 1980;. Kuenstler 2009; Layfield. 2009; Troeh 1999). C factor.

  1. Characterizing soil erosion potential using electrical resistivity imaging : final report.

    Science.gov (United States)

    2017-04-01

    The erosion rate, or erodibility, of soil depends on many soil characteristics including: plasticity, : water content, grain size, percent clay, compaction, and shear strength. Many of these characteristics also : influence soil in situ bulk electric...

  2. Characterizing soil erosion potential using electrical resistivity imaging : technical summary.

    Science.gov (United States)

    2017-04-01

    The erosion rate, or erodibility, of soil depends on many soil characteristics : including: plasticity, water content, grain size, percent clay, compaction, and shear : strength. Many of these characteristics also influence soil in situ bulk electric...

  3. Pedological perspective of gully erosion sites within Kendu ...

    African Journals Online (AJOL)

    use

    ESP); fragile soil structure; high dispersibility; ... sites differed mainly in the ESP, which influenced the soil structure stability, water infiltration rate, and soil dispersibility. ...... Okoth PF (2003). A Hierarchical Method for Soil Erosion Assessment and.

  4. Soil erosion in the Alps : causes and risk assessment

    OpenAIRE

    Meusburger, Katrin

    2010-01-01

    The issue of soil erosion in the Alps has long been neglected due to the low economic value of the agricultural land. However, soil stability is a key parameter which affects ecosystem services like slope stability, water budgets (drinking water reservoirs as well as flood prevention), vegetation productivity, ecosystem biodiversity and nutrient production. In alpine regions, spatial estimates on soil erosion are difficult to derive because the highly heterogeneous biogeophysical structure im...

  5. The importance of erosion for debris flow runout modelling from applications to the Swiss Alps

    Science.gov (United States)

    Frank, F.; McArdell, B. W.; Huggel, C.; Vieli, A.

    2015-04-01

    This study describes an investigation of channel-bed erosion of sediment by debris flows. An erosion model, developed using field data from debris flows at the Illgraben catchment, Switzerland, was incorporated into the existing RAMMS debris-flow model, which solves the 2-D shallow-water equations for granular flows. In the erosion model, the relationship between maximum shear stress and measured erosion is used to determine the maximum potential erosion depth. Additionally, the maximum rate of erosion, measured at the same field site, is used to constrain the erosion rate. The model predicts plausible erosion values in comparison with field data from highly erosive debris flow events at the Spreitgraben torrent channel, Switzerland in 2010, without any adjustment to the coefficients in the erosion model. We find that by including channel erosion in runout models a more realistic flow pattern is produced than in simulations where entrainment is not included. In detail, simulations without channel bed erosion show more lateral outflow from the channel where it has not been observed in the field. Therefore the erosion model may be especially useful for practical applications such as hazard analysis and mapping, as well as scientific case studies of erosive debris flows.

  6. The use of straw to reduce the soil and water losses in agriculture and forest ecosystems in the Mediterranean Type-Ecosystem. The Soil Erosion and Degradation Research Group contribution

    Science.gov (United States)

    Cerda, Artemi; Burguet, Maria; Keesstra, Saskia; Borja, Manuel Esteban Lucas; Hedo, Javier; Brevik, Eric; Pereira, Paulo; Novara, Agata; Jordan, Antonio; Prosdocimi, Massimo; Taguas, Encarnacion

    2016-04-01

    Soil Erosion is a worldwide environmental issue (Keesstra et al., 2007; Dai et al., 2015; Erkossa et al., 2015; Ochoa-Cueva et al., 2015; Taguas et al., 2015). The high erosion rates are affecting mainly the non-developed countries due to the lack of vegetation cover, deforestation and the intense ploughing (Lieskovsky and Kenderessy, 2014; Biwas et al., 2015, Colazo and Buschiazzo, 2015; Ligonja and Shrestha, 2015); and the developing countries due to the herbicides abuse and heavy machinery (Cerdà et al., 2009; Novara et al., 2011). Non-sustainable erosion rates result in the loss of soil and also changes in the hydrological, erosional, biological, and geochemical cycles, which produce the lack of the services, goods and resources the soil offers to the humankind (Keesstra et al., 2012; Berendse et al., 2015; Decock et al., 2015; Brevik et al., 2015; Smith et al., 2015). This is why there is a need to reduce the soil losses, and to achieve a sustainable situation with lower and renewable soil erosion rates and to improve the infiltration rates (Cerdà et al., 2015; Nanko et al., 2015; Mwango et al., 2016). Vegetation cover is the most efficient strategy to control soil and water losses (Cerdà, 1999; Keesstra, 2007; Zhao et al., 2014), however there is the need to use other covers once the vegetation is not recovered such as after the forest fires or when the crops do not allow to have weeds and the soil should be bare. This is sometimes a cultural and aesthetic need (farmers from the Cànyoles river watershed personal comm). Under the above-mentioned circumstances, a straw cover can reduce the soil losses and increase infiltration. This is the main research topic that is being carried out by the Soil Erosion and Degradation Research Group from the University of Valencia during more than one decade: to find solutions to the non-sustainable soil erosion rates under forest and agriculture land under Mediterranean climatic conditions. The research was developed

  7. Erosion prediction for alpine slopes: a symbiosis of remote sensing and a physical based erosion model

    Science.gov (United States)

    Kaiser, Andreas; Neugirg, Fabian; Haas, Florian; Schindewolf, Marcus; Schmidt, Jürgen

    2014-05-01

    As rainfall simulations represent an established tool for quantifying soil detachment on cultivated area in lowlands and low mountain ranges, they are rarely used on steep slopes high mountain ranges. Still this terrain represents productive sediment sources of high morphodynamic. A quantitative differentiation between gravitationally and fluvially relocated material reveals a major challenge in understanding erosion on steep slopes: does solifluction as a result of melting in spring or heavy convective rainstorms during summer cause the essential erosion processes? This paper aims to answer this question by separating gravitational mass movement (solifluction, landslides, mudflow and needle ice) and runoff-induced detachment. First simulated rainstorm experiments are used to assess the sediment production on bare soil on a strongly inclined plot (1 m², 42°) in the northern limestone Alps. Throughout precipitation experiments runoff and related suspended sediments were quantified. In order to enlarge slope length virtually to around 20 m a runoff feeding device is additionally implemented. Soil physical parameters were derived from on-site sampling. The generated data is introduced to the physically based and catchment-scaled erosion model EROSION 3D to upscale plot size to small watershed conditions. Thus infiltration, runoff, detachment, transport and finally deposition can be predicted for single rainstorm events and storm sequences. Secondly, in order to separate gravitational mass movements and water erosion, a LiDAR and structure-from-motion based monitoring approach is carried out to produce high-resolution digital elevation models. A time series analysis of detachment and deposition from different points in time is implemented. Absolute volume losses are then compared to sediment losses calculated by the erosion model as the latter only generates data that is connected to water induced hillside erosion. This methodology will be applied in other watersheds

  8. Predicting soil erosion in Loess areas using a physically based erosion model

    Science.gov (United States)

    Scherer, U.; Zehe, E.

    2003-04-01

    Sediment associated transfer of nutrients and contaminants from agricultural land is a serious threat to surface waters. For planning and managing the sustainable use of water resources information on sediment bound nutrient and contaminant emissions are required. The variation rates of sediment transport to receiving waters in space and time according to the nature of erosion and deposition processes can be determined using physically based numerical models. However these models are often unsuitable for practical application as they require a large set of input parameters which are usually not available on the basin scale. The objective of this research is therefore to derive a basin scale methodology based on easily available input parameters for predicting erosion in Loess regions using the hydrological model CATFLOW and detailed process studies in a small rural German catchment. CATFLOW is based on Richards Equation and the Saint-Venant-Equation to simulate soil water dynamics and overland flow / river flow, including an effective approach for preferential flow and a detailed SVAT model. Soil erosion is modeled using an approach based on shear stress, the momentum balance of precipitation and a semi-empirical erosion resistance. The underlying process studies consist of more than 60 irrigation experiments. To this end we followed a threefold approach: a) development of an effective process model for erosion and derivation of the related parameters based on the process studies; b) generation of a database of erosion events by means of physically based simulations and systematic variation of hillslope geometry, soil types and soil catena, macroporosity, soil moisture, vegetation cover and type and surface preparation; c) derivation of a fuzzy rule based methodology to predict the soil loss per unit area using simple shape-, texture- and vegetation parameters as well as nominal scaled information about surface preparation, which may be easily implemented into a

  9. Infiltration and soil erosion modelling on Lausatian post mine sites

    Science.gov (United States)

    Kunth, Franziska; Schmidt, Jürgen

    2013-04-01

    Land management of reclaimed lignite mine sites requires long-term and safe structuring of recultivation areas. Erosion by water leads to explicit soil losses, especially on heavily endangered water repellent and non-vegetated soil surfaces. Beyond that, weathering of pyrite-containing lignite burden dumps causes sulfuric acid-formation, and hence the acidification of groundwater, seepage water and surface waters. Pyrite containing sediment is detached by precipitation and transported into worked-out open cuts by draining runoff. In addition to ground water influence, erosion processes are therefore involved in acidification of surface waters. A model-based approach for the conservation of man-made slopes of post mining sites is the objective of this ongoing study. The study shall be completed by modeling of the effectiveness of different mine site recultivation scenarios. Erosion risks on man-made slopes in recultivation areas should be determined by applying the physical, raster- and event based computer model EROSION 2D/3D (Schmidt, 1991, 1992; v. Werner, 1995). The widely used erosion model is able to predict runoff as well as detachment, transport and deposition of sediments. Lignite burden dumps contain hydrophobic substances that cover soil particles. Consequently, these soils show strong water repellency, which influences the processes of infiltration and soil erosion on non-vegetated, coal containing dump soils. The influence of water repellency had to be implemented into EROSION 2D/3D. Required input data for soil erosion modelling (e.g. physical soil parameters, infiltration rates, calibration factors, etc.) were gained by soil sampling and rainfall experiments on non-vegetated as well as recultivated reclaimed mine sites in the Lusatia lignite mining region (southeast of Berlin, Germany). The measured infiltration rates on the non-vegetated water repellent sites were extremely low. Therefore, a newly developed water repellency-factor was applied to

  10. Effect of Energy Input Levels on the Dispersibility of some Alfisols at ...

    African Journals Online (AJOL)

    Recent development of the Water Erosion Prediction Project (WEPP) model, which uses water dispersible clay (WDC) in predicting soil erodibility, has led to increased demand for WDC data. The WDC, total clay (TC), and the WDC/TC ratio of a well-drained Oxic Haplustalf, a moderately well drained Typic Plinthustalf and a ...

  11. Water erosion under simulated rainfall in different soil management systems during soybean growth Erosão hídrica sob chuva simulada em diferentes sistemas de manejo do solo durante o crescimento da soja

    Directory of Open Access Journals (Sweden)

    Fernando Luis Engel

    2007-01-01

    Full Text Available Soil management influences soil cover by crop residues and plant canopy, affecting water erosion. The objective of this research was to quantify water and soil losses by water erosion under different soil tillage systems applied on a typical aluminic Hapludox soil, in an experiment carried out from April 2003 to May 2004, in the Santa Catarina highland region, Lages, southern Brazil. Simulated rainfall was applied during five soybean cropstages, at the constant intensity of 64.0 mm h-1. Treatments were replicated twice and consisted of: i conventional tillage on bare soil - control treatment (CTBS, ii conventional tillage on cultivated soil (CTCS, iii no-tillage on non tilled soil with burned crop residue (NTRB, iv no-tillage in non tilled soil with crop residue desiccated (NTRD, and v no-tillage on four-years interrupted soil tillage with crop residue desiccated - "traditional no tillage" (NTRT. Regardless of soybean cropstages, water losses were the highest for the CTCS than for the untilled soils, while soil losses were considerably higher in the CTCS treatment only until cropstage 3, in cultivated soil treatments. The NTRT was most effective treatment in terms of both water and soil loss reduction. Water infiltration should also be considered, when considering the soil erosion process caused by rainfall and its associated runoff, due to the management systems usually adopted in cultivated fields.O manejo do solo influencia a cobertura superficial pelo resíduo cultural e, juntamente com a cobertura do solo pela copa das plantas, afeta a erosao hídrica. O objetivo do estudo foi quantificar as perdas de água e solo por erosão hídrica em diferentes sistemas de manejo do solo, em diferentes estádios do cultivo da soja, em um experimento conduzido de abril de 2003 a maio de 2004, na região do Planalto Catarinense, em um Nitossolo Háplico alumínico. Chuvas simuladas foram aplicadas em cinco estádios do cultivo da soja, com intensidade

  12. Erosivity of rainfall in Lages, Santa Catarina, Brazil

    Directory of Open Access Journals (Sweden)

    Jefferson Schick

    2014-12-01

    Full Text Available The erosive capacity of rainfall can be expressed by an index and knowing it allows recommendation of soil management and conservation practices to reduce water erosion. The objective of this study was to calculate various indices of rainfall erosivity in Lages, Santa Catarina, Brazil, identify the best one, and discover its temporal distribution. The study was conducted at the Center of Agricultural and Veterinary Sciences, Lages, Santa Catarina, using daily rainfall charts from 1989 to 2012. Using the computer program Chuveros , 107 erosivity indices were obtained, which were based on maximum intensity in 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 70, 80, 90, 100, 110, 120, 135, 150, 165, 180, 210, and 240 min of duration and on the combination of these intensities with the kinetic energy obtained by the equations of Brown & Foster, Wagner & Massambani, and Wischmeier & Smith. The indices of the time period from 1993 to 2012 were correlated with the respective soil losses from the standard plot of the Universal Soil Loss Equation (USLE in order to select the erosivity index for the region. Erosive rainfall accounted for 83 % of the mean annual total volume of 1,533 mm. The erosivity index (R factor of rainfall recommended for Lages is the EI30, whose mean annual value is 5,033 MJ mm ha-1 h-1, and of this value, 66 % occurs from September to February. Mean annual erosivity has a return period estimated at two years with a 50 % probability of occurrence.

  13. Improving Rainfall Erosivity Estimates Using Merged TRMM and Gauge Data

    Directory of Open Access Journals (Sweden)

    Hongfen Teng

    2017-11-01

    Full Text Available Soil erosion is a global issue that threatens food security and causes environmental degradation. Management of water erosion requires accurate estimates of the spatial and temporal variations in the erosive power of rainfall (erosivity. Rainfall erosivity can be estimated from rain gauge stations and satellites. However, the time series rainfall data that has a high temporal resolution are often unavailable in many areas of the world. Satellite remote sensing allows provision of the continuous gridded estimates of rainfall, yet it is generally characterized by significant bias. Here we present a methodology that merges daily rain gauge measurements and the Tropical Rainfall Measuring Mission (TRMM 3B42 data using collocated cokriging (ColCOK to quantify the spatial distribution of rainfall and thereby to estimate rainfall erosivity across China. This study also used block kriging (BK and TRMM to estimate rainfall and rainfall erosivity. The methodologies are evaluated based on the individual rain gauge stations. The results from the present study generally indicate that the ColCOK technique, in combination with TRMM and gauge data, provides merged rainfall fields with good agreement with rain gauges and with the best accuracy with rainfall erosivity estimates, when compared with BK gauges and TRMM alone.

  14. A terminological matter: paragenesis, antigravitative erosion or antigravitational erosion ?

    Directory of Open Access Journals (Sweden)

    Pasini G.

    2009-07-01

    Full Text Available In the speleological literature three terms are utilized to designate the “ascending erosion”: paragenesis (= paragénésis, coined in1968, antigravitative erosion (= erosione antigravitativa, coined in 1966 and antigravitational erosion (wrong English translation ofthe Italian term erosione antigravitativa, utilized later on. The term paragenesis should be abandoned because of the priority of theterm erosione antigravitativa - on the ground of the “law of priority” – and because of its ambiguous etimology. On the other hand,the term antigravitational erosion should be forsaken in favour of the term antigravitative erosion, given the meaning that the termsgravitation and gravity have in Physics. Therefore, to designate the phenomenon of the “ascending erosion” there would be nothingleft but the term antigravitative erosion.The antigravitative erosion process and its recognizability are illustrated.Examples of caves with evident antigravitative erosion phenomena, developed in different karstifiable rocks and in several partsof the world, are given.It is recalled that the antigravitative erosion is a phenomenon well-known since 1942 and widely proven and supported, and that it isrelatively easy – in many cases - to recognize the antigravitative origin of karstic passages.It is stressed that the antigravitative erosion is an important phenomenon, exclusive of the karstic caves and unique in nature.

  15. Occurrence of Erosion-Effective Rain in the Brno Area

    Directory of Open Access Journals (Sweden)

    Silvie Kozlovská

    2016-01-01

    Full Text Available Due to the growing awareness of the extent of degradation of agricultural soils as a result of water erosion, increased attention is paid to the establishing of effective erosion control measures based on reliable and timely input data. When determining the vulnerability of farmland to water erosion, the determining factor is erosively dangerous rains, which are defined as totals over 12.5 mm and intensities of more than 24 mm.h-1. This paper analyses the dangerous erosion rainfalls using data on rainfall intensities of precipitation monitoring network of the company Brněnské vodovody a kanalizace, a.s. (BVK in the city of Brno. At first, we have set up 14 rain gauge stations distributed over an area of approximately 105 km2 and set basic indicators of individual rainfall episodes. Then we have analysed their maximum 30-minute intensity, kinetic energy and then determined the factor of erosion efficiency. We have found out a significant spatial variability of these variables throughout the area of the city of Brno. The R-factor analysis revealed that the average annual values of R-factor were the highest in the south-eastern part of the city of Brno while the least dangerous erosion rainfalls occurred in the west.

  16. Quantification Of Erosion Rates Of Agriculturally Used Soils By Artificial

    Science.gov (United States)

    Jha, Abhinand

    2010-05-01

    0.0.1 1. Introduction to soil erosion measurement by radionuclides Soil erosion by water, wind and tillage affects both agriculture and the natural environment. Studying this phenomenon would be one of the advancements in science. Soil erosion occurs worldwide and since the last two decades it has been a main topic of discussion all over the world. The use of environmental radionuclides such as 90Sr, 137Cs to study medium term soil erosion (40 yrs) started in the early 1990's. Using these new techniques better knowledge about erosion can be gained and this knowledge can be implemented for erosion risk management. The erosion and sedimentation study by using man-made and natural radioisotopes is a key technique, which has developed over the past 30 years. Fallout 137Cs and Cosmogenic 7Be are radionuclides that have been used to provide independent measurements of soil-erosion and sediment-deposition rates and patterns [1] [2] [3] [4]. Erosion measurements using radionuclides 137Cs, 7Be Caesium-137 from atmospheric nuclear-weapons tests in the 1950s and 1960s (Fig.1) is a unique tracer of erosion and sedimentation, since there are no natural sources of 137Cs. Unique events such as the Chernobyl accident in April 1986 caused regional dispersal of 137Cs that affects the total global deposition budget. This yearly pattern of fallout can be used to develop a chronology of deposition horizons in lakes, reservoirs, and floodplains. 137Cs can be easily measured by gamma spectroscopy. Using 137Cs is a fast and cheap method to study erosion-deposition processes compared to the traditional methods like silt bags. PIC Figure 1: Global 137Cs fallout (Modified from SAAS Bulletin 353, Part E, DDR, 1986) When 137Cs, 7Be reach the soil surface by wet and dry deposition, they are quickly and strongly adsorbed by ion exchange and are essentially non exchangeable in most environments. Each radionuclide is distributed differently in the soil because of differences in half-lives (30 yrs

  17. A qualitative and quantitative investigation into the effect of fluoride formulations on enamel erosion and erosion-abrasion in vitro.

    Science.gov (United States)

    Austin, R S; Stenhagen, K S; Hove, L H; Dunne, S; Moazzez, R; Bartlett, D W; Tveit, A B

    2011-10-01

    To investigate the effect of a single application of highly concentrated SnF(2) and NaF solutions and a NaF/CaF(2) varnish on human enamel subjected to hydrochloric acid erosion and tooth brush abrasion. Forty enamel samples were prepared from human third molars and NaF (9500ppm, pH 8.0), SnF(2) (9500ppm, pH 2.6) solutions; Bifluorid10(®) varnish (42,500ppm, NaF 5%, CaF(2) 5%) and deionized water (control) was applied to the enamel. Following this three, six and nine cycles of erosion [1 cycle=erosion (0.01M HCl, pH 2.2, 2min)+artificial saliva (1h, pH 7.0)] and erosion-abrasion [1 cycle=erosion (0.01M HCl, pH 2.2, 2min)+artificial saliva (1h, pH 7.0)+abrasion (120 linear strokes in artificial saliva from Tepe medium soft brushes 200g loading)] were carried out. The fluoride treated enamel was analysed using Knoop microhardness, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). For erosion alone, there was significantly less microhardness reduction in the Bifluorid10(®) group after three and six cycles of erosion (P0.05). The EDS analysis showed that only the Bifluorid10(®) group had any detectable fluorine following erosion and erosion-abrasion (0.1wt.% and 0.2wt.% fluorine respectively). The surface fluorine was found to have been removed after erosion and erosion-abrasion for all other surface treatments. Although precipitates were observed after application of the surface treatments, following erosion-abrasion, no visible surface effects from any fluoride preparation remained. Enamel surface precipitates from application NaF, SnF(2) solutions appear to not be able to provide protection against gastric erosion and tooth brush abrasion. The NaF/CaF(2) varnish provided limited protection against erosion but the role for such varnishes in gastric erosion and tooth brush abrasion remains uncertain. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Chemical erosion intensity in the Nišava catchments

    Directory of Open Access Journals (Sweden)

    Manojlović Predrag A.

    2002-01-01

    Full Text Available The Nišava catchment comprehends the area of 4068 km2. There are differences in erosion intensity due to different physical-geographical characteristics of that area. Mechanical water erosion in the Nišava catchment is 302,4 m3/km2/yr and chemical erosion is 67,2 t/km2/yr. Space differences are large (47,1-115.5 t/km2/yr and are mostly determined by hydrological and lithological characteristics of that area.

  19. Soil Erosion and Agricultural Sustainability

    National Research Council Canada - National Science Library

    David R. Montgomery

    2007-01-01

    .... The general equivalence of the latter indicates that, considered globally, hillslope soil production and erosion evolve to balance geologic and climate forcing, whereas conventional plow-based...

  20. Multiperspective analysis of erosion tolerance

    Directory of Open Access Journals (Sweden)

    Sparovek Gerd

    2003-01-01

    Full Text Available Erosion tolerance is the most multidisciplinary field of soil erosion research. Scientists have shown lack in ability to adequately analyze the huge list of variables that influence soil loss tolerance definitions. For these the perspectives of erosion made by farmers, environmentalists, society and politicians have to be considered simultaneously. Partial and biased definitions of erosion tolerance may explain not only the polemic nature of the currently suggested values but also, in part, the nonadoption of the desired levels of erosion control. To move towards a solution, considerable changes would have to occur on how this topic is investigated, especially among scientists, who would have to change methods and strategies and extend the perspective of research out of the boundaries of the physical processes and the frontiers of the academy. A more effective integration and communication with the society and farmers, to learn about their perspective of erosion and a multidisciplinary approach, integrating soil, social, economic and environmental sciences are essential for improved erosion tolerance definitions. In the opinion of the authors, soil erosion research is not moving in this direction and a better understanding of erosion tolerance is not to be expected in the near future.

  1. Evaluating the new soil erosion map of Hungary

    Science.gov (United States)

    Waltner, István; Centeri, Csaba; Takács, Katalin; Pirkó, Béla; Koós, Sándor; László, Péter; Pásztor, László

    2017-04-01

    With growing concerns on the effects of climate change and land use practices on our soil resources, soil erosion by water is becoming a significant issue internationally. Since the 1964 publication of the first soil erosion map of Hungary, there have been several attempts to provide a countrywide assessment of erosion susceptibility. However, there has been no up-to-date map produced in the last decade. In 2016, a new, 1:100 000 scale soil erosion map was published, based on available soil, elevation, land use and meteorological data for the extremely wet year of 2010. The map utilized combined outputs for two spatially explicit methods: the widely used empirical Universal Soil Loss Equation (USLE) and the process-based Pan-European Soil Erosion Risk Assessment (PESERA) models. The present study aims to provide a detailed analysis of the model results. In lieu of available national monitoring data, information from other sources were used. The Soil Degradation Subsystem (TDR) of the National Environmental Information System (OKIR) is a digital database based on a soil survey and farm dairy data collected from representative farms in Hungary. During the survey all kind of degradation forms - including soil erosion - were considered. Agricultural and demographic data was obtained from the Hungarian Central Statistical Office (KSH). Data from an interview-based survey was also used in an attempt to assess public awareness of soil erosion risks. Point-based evaluation of the model results was complemented with cross-regional assessment of soil erosion estimates. This, combined with available demographic information provides us with an opportunity to address soil erosion on a community level, with the identification of regions with the highest risk of being affected by soil erosion.

  2. Regionalization of monthly rainfall erosivity patterns in Switzerland

    Directory of Open Access Journals (Sweden)

    S. Schmidt

    2016-10-01

    Full Text Available One major controlling factor of water erosion is rainfall erosivity, which is quantified as the product of total storm energy and a maximum 30 min intensity (I30. Rainfall erosivity is often expressed as R-factor in soil erosion risk models like the Universal Soil Loss Equation (USLE and its revised version (RUSLE. As rainfall erosivity is closely correlated with rainfall amount and intensity, the rainfall erosivity of Switzerland can be expected to have a regional characteristic and seasonal dynamic throughout the year. This intra-annual variability was mapped by a monthly modeling approach to assess simultaneously spatial and monthly patterns of rainfall erosivity. So far only national seasonal means and regional annual means exist for Switzerland. We used a network of 87 precipitation gauging stations with a 10 min temporal resolution to calculate long-term monthly mean R-factors. Stepwise generalized linear regression (GLM and leave-one-out cross-validation (LOOCV were used to select spatial covariates which explain the spatial and temporal patterns of the R-factor for each month across Switzerland. The monthly R-factor is mapped by summarizing the predicted R-factor of the regression equation and the corresponding residues of the regression, which are interpolated by ordinary kriging (regression–kriging. As spatial covariates, a variety of precipitation indicator data has been included such as snow depths, a combination product of hourly precipitation measurements and radar observations (CombiPrecip, daily Alpine precipitation (EURO4M-APGD, and monthly precipitation sums (RhiresM. Topographic parameters (elevation, slope were also significant explanatory variables for single months. The comparison of the 12 monthly rainfall erosivity maps showed a distinct seasonality with the highest rainfall erosivity in summer (June, July, and August influenced by intense rainfall events. Winter months have the lowest rainfall erosivity. A

  3. Regional differentiation regular and comprehensive partition of soil erosion in the lower Jinsha River

    Science.gov (United States)

    Su, Fenghuan; Ge, Yonggang

    2017-04-01

    Based on erosion force, the soil erosion types in the lower reaches of the Jinsha river were divided into water erosion, water erosion-gravity erosion, water-karst erosion, freeze-thaw erosion. The scope of different erosion type was determined by means of remote sensing interpretation and field investigation. Based on the universal soil loss equation, the single factor sensitivity such as rainfall, terrain, soil erodibility, vegetation coverage was analyzed. Then comprehensive assessment model of the water erosion is built. We selected six factors such as slope, relative height difference, lithology, distance to fault, average rainfall, ground motion peak acceleration and assessed susceptibility of landslide and debris flow. The karst severity was analyzed based on rocky desertification distribution. We analyzed the characteristics of the different regional differentiation. In the end, the comprehensive regionalization map of soil erosion was drawn, which comprised 5 region and 12 sub-regions. the result will provide the important basis of the partition management of ecology environment, the reasonable use of land resources, effective control of soil in the lower reaches of the Jinsha River.

  4. Erosion mechanism and erosion products in carbon-based materials

    Energy Technology Data Exchange (ETDEWEB)

    Arkhipov, N.; Bakhtin, V.; Barsuk, V.; Kurkin, S.; Mironova, E.; Piazza, G.; Safronov, V. E-mail: vsafr@rico.ttk.ru; Scaffidi-Argentina, F.; Toporkov, D.; Vasenin, S.; Wuerz, H.; Zhitlukhin, A

    2002-12-01

    Plasma/material interaction was studied in disruption simulation experiments at the plasma gun facility MK-200. Graphite and carbon-fibre composites were exposed to pulsed energetic plasma under heat loads typically expected for disruptions in future tokamaks. Erosion rates, erosion mechanisms and the properties of the eroded carbon have been studied.

  5. Interrill and rill erosion quantification using ground-based stereophotogrammetry technique - A case study from the bare plot of Mollisol, Northeast China

    Science.gov (United States)

    Li, Hao; Zhang, Xingyi

    2017-04-01

    The erosion processes at the hillslope scale most commonly encountered are interrill and rill erosion, proved by wide-spread RUSLE 2 and WEPP model. A significant problem related to the study of hillslope erosion within the field research consists in separating interrill and rill erosion amount from total erosion, mainly due to lack of precise measurement techniques. Stereophotogrammetry is a low-cost and user-friendly technology that could build high resolution three-dimensional (3D) model using structure-from-motion (SFM) software, allowing measuring the microtopography spatial variation and successive change within the hillslope after each erosive rainfall event, from which the interrill and rill erosion amount could be measured precisely. This paper reports the results of a field investigation on the interrill and rill morphology and soil loss as well as temporary change under natural rainfall events (2015-2016) using ground-based stereophotogrammetry, at a typical Mollisol zone, Northeast China. The experiments were carried out at in a 22.0*4.5 m bare plot with 5 gradients. The three-dimensional coordinates of control and check points outside the plot were measured by total station at May before rainfall season each year, in order to build bare plot's local coordinate system. Around 500 photos covering the whole plot were taken after rainfall event. The plot surface's high-density point clouds and interpolated Digital Elevation Models (DEMs) were constructed by PIX4D 2.0 using above photos and control points. The CloudCompare was used to analysis point clouds for interrill and rill morphology and successive change as well as respectively soil loss of the bare plot after each erosive rainfall. The ArcGIS was applied for sediment connectivity analysis to evaluate the potential effect of connectivity using DEM, which could help rill initial formation understanding. The results showed that the mean root mean square (RMS) error of the check points was 3 mm, and the

  6. A probabilistic approach to modeling postfire erosion after the 2009 Australian bushfires

    Science.gov (United States)

    P. R. Robichaud; W. J. Elliot; F. B. Pierson; D. E. Hall; C. A. Moffet

    2009-01-01

    Major concerns after bushfires and wildfires include increased flooding, erosion and debris flows due to loss of the protective forest floor layer, loss of water storage, and creation of water repellent soil conditions. To assist postfire assessment teams in their efforts to evaluate fire effects and make postfire treatment decisions, a web-based Erosion Risk...

  7. Soil erosion from harvested sites versus streamside management zone sediment deposition in the Piedmont of Virginia

    Science.gov (United States)

    William A. Lakel; W. Michael Aust; C. Andrew Dolloff; Amy W. Easterbrook

    2006-01-01

    Forestry best management practices were primarily developed to address two major issues related to soil erosion: water quality and site productivity. Sixteen watersheds managed as loblolly pine plantations in the piedmont region were monitored for soil erosion and water quality prior to treatment. Subsequently, all watersheds were harvested with clearcutting, ground-...

  8. Soil Erosion in Britain: Updating the Record

    Directory of Open Access Journals (Sweden)

    John Boardman

    2013-08-01

    Full Text Available Concern about soil erosion on arable land in Britain dates back at least 40 years. Monitoring schemes and case studies have subsequently identified the areas at risk, the rates and frequencies and the major factors responsible for erosion. Initial concern focused on impacts on the farm and therefore on food production. Latterly the emphasis has shifted to off-farm impacts particularly reservoir sedimentation, muddy flooding of properties and the ecological damage to watercourses due to nutrient enrichment, pesticides and damage to fish spawning grounds from fine-sediment inputs. The shift has therefore been to concerns about a healthy and sustainable environment which includes soils. Government agencies, the water companies and the farming industry have lagged behind scientific studies in recognising and addressing erosion problems. Attempts at mitigation are now largely driven by the need to comply with the EU Water Framework Directive whereby watercourses must reach “good status” by 2015. Future changes in land use and climate will offer further challenges in terms of effective monitoring and compliance.

  9. Rangeland Hydrology and Erosion Model

    Science.gov (United States)

    Nearing, Mark; Pierson, Fred; Hernandez, Mariano; Al-Hamdan, Osama; Weltz, Mark; Spaeth, Ken; Wei, Haiyan; Stone, Jeff

    2013-04-01

    Soil loss rates on rangelands are considered one of the few quantitative indicators for assessing rangeland health and conservation practice effectiveness. An erosion model to predict soil loss specific for rangeland applications has been needed for many years. Most erosion models were developed from croplands where the hydrologic and erosion processes are different, largely due to much higher levels of heterogeneity in soil and plant properties at the plot scale and the consolidated nature of the soils. The Rangeland Hydrology and Erosion Model (RHEM) was designed to fill that need. RHEM is an event-based model that estimates runoff, erosion, and sediment delivery rates and volumes at the spatial scale of the hillslope and the temporal scale of a single rainfall event. It represents erosion processes under normal and fire-impacted rangeland conditions, it adopts a new splash erosion and thin sheet-flow transport equation developed from rangeland data, and it links the model hydrologic and erosion parameters with rangeland plant communities by providing a new system of parameter estimation equations based on 204 plots at 49 rangeland sites distributed across 15 western U.S. states. Recent work on the model is focused on representing intra-storm dynamics, using stream-power as the driver for detachment by flow, and deriving parameters for after-fire conditions.

  10. Dune erosion during storm surges

    NARCIS (Netherlands)

    Van Thiel de Vries, J.S.M.

    2009-01-01

    Large parts of The Netherlands are protected from flooding by a narrow strip of sandy beaches and dunes. The aim of this thesis is to extend the existing knowledge of dune erosion during storm surges as it occurs along the Dutch coast. The thesis discusses: • A large scale dune erosion experiment to

  11. Aspectos financeiros relacionados às perdas de nutrientes por erosão hídrica em diferentes sistemas de manejo do solo Financial aspects of nutrient losses by water erosion in different soil management systems

    Directory of Open Access Journals (Sweden)

    Ildegardis Bertol

    2007-02-01

    SD e o PM comportaram-se de modo semelhante em termos de valor monetário das referidas perdas, em cujos tratamentos as perdas de água e solo foram expressivamente menores que no preparo convencional. O valor monetário da perda anual por hectare de K expresso na forma de cloreto de potássio, por erosão hídrica, foi equivalente a 2,6 vezes aquele representado pelo somatório das perdas de P na forma de superfosfato triplo e de Ca e Mg na forma de calcário, na média dos sistemas de manejo do solo. Na SD, essas perdas foram de US$ 14,83 por hectare por ano, enquanto no PM foram de US$ 16,33 e, no PC, de US$ 24,94. Na média destes sistemas de manejo do solo, o valor monetário total anual por hectare das perdas de P expresso na forma de superfosfato triplo correspondeu a 8,6 %, enquanto de K na forma de cloreto de potássio e de Ca e Mg expressos na forma de calcário o valor correspondeu a 76,8 e 14,6 %, respectivamente.Water erosion is the most deleterious form of soil degradation. Besides reducing the production capacity of soils for crops, it causes strong financial and environmental impacts, due to the nutrient losses associated with it. This research work was developed with the objective of quantifying water and soil losses, P, K, Ca, and Mg losses in runoff water and extracted P, and exchangeable K, Ca and Mg losses in runoff sediments, caused by rainfall erosion, in an experiment conducted under natural rainfall, in the period from November, 1992 to October, 2003, in the south of the region Planalto Catarinense, in Santa Catarina State, Brazil. The financial value of these nutrients were calculated, expressed in triple phosphate (P, potassium chloride (K, and limestone (Ca and Mg, which were lost through water erosion from an Inceptsoil with 0.10 m m-1 slope steepness, under the following three different soil management systems: (a conventional tillage (CT, (b minimum tillage (MT, and (c no tillage (NT, in duplication. One of the replications was

  12. Experiments for understanding soil erosion processes

    Science.gov (United States)

    Seeger, Manuel

    2015-04-01

    Soil erosion processes are usually quantified by observation and measurement of their related forms. Rill, and gullies, moulds or sediment sinks are often used to estimate the soil loss. These forms are generally related directly to different types of processes, thus are also used to identify the dominant processes on a certain type of land-use. Nevertheless, the direct observation of erosion processes is constrained by their temporal and spatial erratic occurrence. As a consequence, the process understanding is generally deduced by analogies. Another possibility is to reproduce processes in experiments in both, the lab and in the field. Laboratory experiments are implemented when we want to have full control over all parameters we think are relevant for the process in our focus. So are very useful for identification of parameters influencing processes and their intensities, but also as physical models of the processes and process interactions in our focus. Therefore, we can use them to verify our concepts, and to define relevant parameters. Field experiments generally only simulate with controlled driving forces, this is the rain or the runoff, but dealing with the uncertainty of our study object, the soil. This enables two things: 1) similar as with lab experiments, we are able to identify processes and process interactions and so, to get a deeper understanding of soil erosion; 2) experiments are suitable for providing data about singular processes in the field and thus, to provide data suitable for model parametrisation and calibration. These may be quantitative data about erodibility or soil resistance, sediment detachment or transport. The Physical Geography Group at Trier University has a long lasting experience in the application of experiments in soil erosion research in the field, and has become lead in the further development conception and of devices and procedures to investigate splash detachment and initial transport of soil particles by wind and water

  13. Modelling soil erosion reduction by mahonia aquifolium on hillslopes in hungary: The impact of soil stabilization by roots

    NARCIS (Netherlands)

    Hudek, C.; Sterk, Geert; van Beek, Rens L P H; de Jong, Steven M.

    2014-01-01

    Agricultural activities on hillslopes often cause soil erosion and degradation. Permanent vegetation strips on cultivated slopes could be an effective soil conservation technique to reduce erosion. Previous studies showed that cultivated Mahonia aquifolium can be an effective plant for water erosion

  14. Ground freezing effects on soil erosion of army training lands

    National Research Council Canada - National Science Library

    Halvorson, Jonathan J

    1998-01-01

    .... Rut edges were zones of erosion and sidewall bases were zones of deposition. Ksubfs values were similar in and out of ruts formed on soil with 0-5 percent water by volume, but were lower in ruts formed on soil with about 15 percent water...

  15. Soil erosion assessment in the core area of the Loss Plateau

    Science.gov (United States)

    Yang, Bo; Wang, Quanjiu

    2017-11-01

    In order to explore the spatiotemporal evolution of erosion and sediment yield before and after Grain for Green Project in the Loss Plateau. The soil loss of Yulin is estimated by Chinese Water Erosion on Hill Slope Prediction Model. The result shows that the spatiotemporal variations of soil erosion are largely related to rainfall erosion distribution, slope, and land use type. The overall soil erosion categories in the south region are higher than that of the northwest. Mid slopes and valleys are the major topographical contributors to soil erosion. With the growth of slope gradient, soil erosion significantly increased. The soil loss has a decreasing tendency after Grain for Green Project. The results indicate that the vegetation restoration as part of the Grain for Green Project on the Loess Plateau is effective.

  16. Modeling soil erosion in a watershed

    OpenAIRE

    Lanuza, R.

    1999-01-01

    Most erosion models have been developed based on a plot scale and have limited application to a watershed due to the differences in aerial scale. In order to address this limitation, a GIS-assisted methodology for modeling soil erosion was developed using PCRaster to predict the rate of soil erosion at watershed level; identify the location of erosion prone areas; and analyze the impact of landuse changes on soil erosion. The general methodology of desktop modeling or soil erosion at watershe...

  17. Dietary behavior and knowledge of dental erosion among Chinese adults

    Directory of Open Access Journals (Sweden)

    Pang Karie KL

    2010-06-01

    Full Text Available Abstract Objectives To study the dietary behavior and knowledge about dental erosion and self-reported symptoms that can be related to dental erosion among Chinese adults in Hong Kong. Methods Chinese adults aged 25-45 years were randomly selected from a list of registered telephone numbers generated by computer. A telephone survey was administered to obtain information on demographic characteristics, dietary habits, dental visits, and knowledge of and presence of self-reported symptoms that can be related to dental erosion. Results A total of 520 participants were interviewed (response rate, 75%; sampling error, ± 4.4% and their mean age was 37. Most respondents (79% had ever had caries, and about two thirds (64% attended dental check-ups at least once a year. Respondents had a mean of 5.4 meals per day and 36% had at least 6 meals per day. Fruit (89% and lemon tea/water (41% were the most commonly consumed acidic food and beverage. When asked if they ever noticed changes in their teeth, most respondents (92% said they had experienced change that can be related to erosion. However, many (71% had never heard about dental erosion and 53% mixed up dental erosion with dental caries. Conclusion Hong Kong Chinese adults have frequent intake of food and many have experienced symptoms that can be related to dental erosion. Their level of awareness of and knowledge about dental erosion is generally low, despite most of them have regular dental check-ups. Dental health education is essential to help the public understand dental erosion and its damaging effects.

  18. Vegetarian children and dental erosion.

    Science.gov (United States)

    al-Dlaigan, Y H; Shaw, L; Smith, A J

    2001-05-01

    There have been recent changes in teenage lifestyle and diet. The increasing consumption of soft drinks and foods containing significant acidic components may play a role in the development of dental erosion. The aims of this investigation were firstly to assess the prevalence of vegetarian children in a cluster random sample of 14-year-old children in Birmingham, United Kingdom. Secondly, to determine the prevalence of dental erosion in these children, and thirdly, to see if there were any differences between vegetarian and non-vegetarian children in the prevalence of dental erosion and dietary intake. A cluster random sample of 418 14-year-old children (209 males and 209 females) were examined from 12 different schools in Birmingham, United Kingdom; a dietary questionnaire was completed and the levels of tooth wear were recorded using a modification of the (TWI) index. All data were analysed using SPSS with t-test and Chi-square analysis. Significance was accepted at the P children were vegetarian; 52% of them had low dental erosion and 48% moderate dental erosion. Statistically there were no significant differences between vegetarian and non-vegetarian children in the prevalence of erosion; however, there were significant differences in some food and drink consumption. It was concluded that dental erosion is common in teenage children, but there were no significant differences in prevalence between vegetarian and non-vegetarian children.

  19. Rinsing with antacid suspension reduces hydrochloric acid-induced erosion.

    Science.gov (United States)

    Alves, Maria do Socorro Coelho; Mantilla, Taís Fonseca; Bridi, Enrico Coser; Basting, Roberta Tarkany; França, Fabiana Mantovani Gomes; Amaral, Flávia Lucisano Botelho; Turssi, Cecilia Pedroso

    2016-01-01

    Mouthrinsing with antacids, following erosive episodes, have been suggested as a preventative strategy to minimize tooth surface loss due to their neutralizing effect. The purpose of this in situ study was to evaluate the effect of an antacid suspension containing sodium alginate, sodium bicarbonate and calcium carbonate in controlling simulated erosion of enamel of intrinsic origin. The experimental units were 48 slabs (3×3×2mm) of bovine enamel, randomly divided among 12 volunteers who wore palatal appliances with two enamel slabs. One of them was exposed extra-orally twice a day to 25mL of a hydrochloric acid (HCl) solution (0.01M, pH 2) for 2min. There were two independent phases, lasting 5 days each. In the first phase, according to a random scheme, half of the participants rinsed with 10mL of antacid suspension (Gaviscon(®), Reckitt Benckiser Healthcare Ltd.), while the remainder was rinsed with deionized water, for 1min. For the second phase, new slabs were inserted and participants switched to the treatment not received in the first stage. Therefore, the groups were as follows: (a) erosive challenge with HCl+antacid suspension; (b) erosive challenge with HCl+deionized water (DIW); (c) no erosive challenge+antacid suspension; (d) no erosive challenge+DIW. Specimens were assessed in terms of surface loss using optical profilometry and Knoop microhardness. The data were analyzed using repeated measures two-way analysis of variance and Tukey's tests. Compared to DIW rinses, surface loss of enamel was significantly lower when using an antacid rinse following erosive challenges (p=0.015). The Knoop microhardness of the enamel was significantly higher when the antacid rinse was used (p=0.026). The antacid suspension containing sodium alginate, sodium bicarbonate and calcium carbonate, rinsed after erosive challenges of intrinsic origin, reduced enamel surface loss. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Cavitation erosion size scale effects

    Science.gov (United States)

    Rao, P. V.; Buckley, D. H.

    1984-01-01

    Size scaling in cavitation erosion is a major problem confronting the design engineers of modern high speed machinery. An overview and erosion data analysis presented in this paper indicate that the size scale exponent n in the erosion rate relationship as a function of the size or diameter can vary from 1.7 to 4.9 depending on the type of device used. There is, however, a general agreement as to the values of n if the correlations are made with constant cavitation number.

  1. Estimation Model of Soil Freeze-Thaw Erosion in Silingco Watershed Wetland of Northern Tibet

    Directory of Open Access Journals (Sweden)

    Bo Kong

    2013-01-01

    Full Text Available The freeze-thaw (FT erosion is a type of soil erosion like water erosion and wind erosion. Limited by many factors, the grading evaluation of soil FT erosion quantities is not well studied. Based on the comprehensive analysis of the evaluation indices of soil FT erosion, we for the first time utilized the sensitivity of microwave remote sensing technology to soil moisture for identification of FT state. We established an estimation model suitable to evaluate the soil FT erosion quantity in Silingco watershed wetland of Northern Tibet using weighted summation method of six impact factors including the annual FT cycle days, average diurnal FT phase-changed water content, average annual precipitation, slope, aspect, and vegetation coverage. Finally, with the support of GIS, we classified soil FT erosion quantity in Silingco watershed wetland. The results showed that soil FT erosion are distributed in broad areas of Silingco watershed wetland. Different soil FT erosions with different intensities have evidently different spatial and geographical distributions.

  2. Estimation model of soil freeze-thaw erosion in Silingco watershed wetland of Northern Tibet.

    Science.gov (United States)

    Kong, Bo; Yu, Huan

    2013-01-01

    The freeze-thaw (FT) erosion is a type of soil erosion like water erosion and wind erosion. Limited by many factors, the grading evaluation of soil FT erosion quantities is not well studied. Based on the comprehensive analysis of the evaluation indices of soil FT erosion, we for the first time utilized the sensitivity of microwave remote sensing technology to soil moisture for identification of FT state. We established an estimation model suitable to evaluate the soil FT erosion quantity in Silingco watershed wetland of Northern Tibet using weighted summation method of six impact factors including the annual FT cycle days, average diurnal FT phase-changed water content, average annual precipitation, slope, aspect, and vegetation coverage. Finally, with the support of GIS, we classified soil FT erosion quantity in Silingco watershed wetland. The results showed that soil FT erosion are distributed in broad areas of Silingco watershed wetland. Different soil FT erosions with different intensities have evidently different spatial and geographical distributions.

  3. [Effects of different re-vegetation patterns on soil organic carbon and total nitrogen in the wind-water erosion crisscross region, China].

    Science.gov (United States)

    Liu, Xue-tong; Wei, Yan-chun; Yang, Xian-long; Hao, Ming-de; Wei, Xiao-rong

    2016-01-01

    This study was conducted to analyze the responses of soil organic carbon (SOC) and total nitrogen (TN) to three typical re-vegetation patterns, i.e., grassland, alfalfa land and peashrub land on the Loess Plateau of China, and also to assess the dynamics of SOC and TN with re-vegetation age. The results showed that all the three re-vegetation practices increased the concentrations of SOC and TN in the 0-10 cm soil layer, but their effects differed with re-vegetation age. Compared with adjacent croplands, the concentrations of SOC and TN in the 0-10 cm soil layer in grassland did not change within 10 years of succession, but increased after 20 years of succession. In alfalfa land, the concentrations of SOC and TN increased by 51.6%-82.9% and 43.4%-67.0% in the 0-10 cm soil layer, with the increasing rates of stocks of SOC and TN being 0.17-0.46 and 0.015-0.043 t · hm⁻² · a⁻¹, respectively. However, SOC and TN were not affected by re-vegetation age in alfalfa land. The increases of concentrations of SOC and TN remained high in the first 20 years after conversion of cropland to peashrub land, but decreased after 40 years of conversion. In conclusion, the conversion of croplands to peashrub or alfalfa land could be better in contributing to high stocks of SOC and TN than natural succession of grassland. However, their positive effects on the enrichment of SOC and TN may not be sustainable due to the scarcity of soil moisture and high water consumption of these two re-vegetation plants.

  4. Land susceptibility to soil erosion in Orashi Catchment, Nnewi South, Anambra State, Nigeria

    OpenAIRE

    S. Odunuga; A. Ajijola; N. Igwetu; O. Adegun

    2018-01-01

    Soil erosion is one of the most critical environmental hazards that causes land degradation and water quality challenges. Specifically, this phenomenon has been linked, among other problems, to river sedimentation, groundwater pollution and flooding. This paper assesses the susceptibility of Orashi River Basin (ORB) to soil erosion for the purpose of erosion control measures. Located in the South Eastern part of Nigeria, the ORB which covers approximately 413.61 km2 is curre...

  5. Compost for steep slope erosion.

    Science.gov (United States)

    2008-06-01

    This study was initiated to develop guidelines for maintenance erosion control measures for steep slopes. The study focused on evaluating and monitoring KY-31 fescue germination rates using two media treatments 1) 100 percent by weight compost and 2)...

  6. Erosion-resistant composite material

    Science.gov (United States)

    Finch, C.B.; Tennery, V.J.; Curlee, R.M.

    A highly erosion-resistant composite material is formed of chemical vapor-deposited titanium diboride on a sintered titanium diboride-nickel substrate. This material may be suitable for use in cutting tools, coal liquefaction systems, etc.

  7. The Impact of Farming and Land Ownership on Soil Erosion

    Directory of Open Access Journals (Sweden)

    Olga Čermáková

    2014-01-01

    Full Text Available The aim of this paper was to compare two methods of farming, especially their effect on water soil erosion. The examined methods were (1 large-scale farming, where more than 50% of the land was leased, and (2 small-scale farming, where the land was almost exclusively privately owned. The research area was 8 cadastres in the district of Hodonín, South Moravia, Czech Republic. In these cadastres 48 land blocks representing both large-scale and small-scale farming (i.e. owners and tenants were chosen. The long-term average annual soil loss caused by water erosion (G was calculated using the erosion model USLE 2D and ArcGIS 10.1. The nonparametric Mann-Whitney test was used for the statistical evaluation of the data. The difference between the soil loss (G on land blocks farmed by small producers (owners and large producers (tenants was significant (p < 0.05. Differences between the values of the cropping-management factor (C were not statistically significant (p = 0.054. Based on the analysis of other variables in the USLE equation it can be stated that a continuous slope length, conditioned by the size of land blocks, played an important role in the amount of soil loss caused by water erosion. Above all, to protect the soil from erosion and maintain soil quality it is necessary to reduce the size of land blocks farmed by tenants and improve the crop rotation systems.

  8. Perdas de solo e água num Latossolo Vermelho aluminoférrico submetido a diferentes sistemas de preparo e cultivo sob chuva natural Water erosion caused by natural rainfall in a clayey Hapludox with different cropland tillage systems

    Directory of Open Access Journals (Sweden)

    J. F. Beutler

    2003-06-01

    active agents of water erosion, furthermore influenced by soil cover and roughness, crop and soil tillage. Compared to conventional tillage, water erosion is reduced in soil conservation tillage because this method is less intensive, preserves the cover longer, and sometimes increases soil roughness. Erosion losses (soil and water of a clayey Hapludox with a slope of 0.09 m m-1 were evaluated in Chapecó, Santa Catarina State, Brazil, from November 1994 to October 1999 under natural rainfall. The treatments, in two replications, consisted of the following downslope soil tillage systems: no-tillage, conventional tillage, minimum tillage, and tillage rotation, with some summer and winter crop rotation combinations, and conventional tillage without crop (standard unit of the Universal Soil Loss Equation-USLE as control. In no-tillage with crop rotation there was a soil loss reduction of 45 % in relation to summer conventional tillage and to winter no-tillage crop rotation systems, and of 99 % in relation to bare soil. Conservation tillage reduced the mean soil loss by 80 % in relation to conventional tillage. Mean soil losses were twice as high during the spring/summer as in the fall/winter period in no-tillage treatments, while in the other treatments average losses of the crop years were 3.3 higher in fall/winter. Water losses were small, with a behavior similar to that of the soil losses, in spite of the quantity difference.

  9. Wind erosion of soils burned by wildfire

    Science.gov (United States)

    N. S. Wagenbrenner; M. J. Germino; B. K. Lamb; R. B. Foltz; P. R. Robichaud

    2011-01-01

    Wind erosion and aeolian transport processes are largely unstudied in the post-wildfire environment, but recent studies have shown that wind erosion can play a major role in burned landscapes. A wind erosion monitoring system was installed immediately following a wildfire in southeastern Idaho, USA to measure wind erosion from the burned area (Figure 1). This paper...

  10. Rainfall Erosivity in Southeastern Nigeria | Ezemonye | Ethiopian ...

    African Journals Online (AJOL)

    Calabar Owerri and Port-Harcourt recorded the highest erosive storms/ more months of very high erosivity index. The deterministic relationship between kinetic energy of rains and erosivity pattern observed for the different stations showed that erosive rains contribute significantly to detachment of soil materials in the study ...

  11. Effect of erodent particles on the erosion of metal specimens

    Energy Technology Data Exchange (ETDEWEB)

    Razzaque, M. Mahbubur, E-mail: mmrazzaque@me.buet.ac.bd; Alam, M. Khorshed; Khan, M. Ishak, E-mail: ishak.buet@gmail.com [Department of Mechanical Engineering Bangladesh University of Engineering and Technology (BUET), Dhaka (Bangladesh)

    2016-07-12

    This paper presents the experimental results of the measurement of erosion rate of carbon steel specimens in sand water slurry system in a slurry pot tester. Sylhet sand has been sieved to get three sizes of erodent particles; namely, less than 250 micron, 250 to 590 micron and 590 to 1190 micron. Experiments are done with three sand concentrations (10%, 15% and 20%). The rate of erosion of the carbon steel specimens is measured as the loss of weight per unit surface area per unit time under the dynamic action of solid particles. The eroded surfaces of the specimens are examined using Scanning Electron Microscopy (SEM) to visualize the impact of the slurry of various conditions. It is seen that irrespective of the particle size the rate of erosion increases with the increase of slurry concentration. This increment of erosion rate at high concentration is high for large particles. High erosion rate is observed in case of large sand particles. In case of small and fine particles erosion rate is small because of low impact energy as well as the wastage of energy to overcome the hindrance of the finer particles before striking on the specimen surface.

  12. Toothpaste prevents debonded brackets on erosive enamel.

    Science.gov (United States)

    Barros, Érico Luiz Damasceno; Pinto, Shelon Cristina Souza; Borges, Alvaro Henrique; Tonetto, Mateus Rodrigues; Ellwood, Roger Phillip; Pretty, Ian; Bandéca, Matheus Coelho

    2015-01-01

    This study evaluated the effect of high fluoride dentifrice on the bond strength of brackets after erosive challenge. Eighty-four enamel specimens were divided into seven groups (n = 12): WN (distilled water/no acid challenge), W3C (distilled water/3 cycles of acid challenge), and W6C (distilled water/6 cycles of acid challenge) were not submitted to dentifrice treatment. Groups RF3C (regular fluoride dentifrice/3 cycles of acid challenge) and RF6C (regular fluoride dentifrice/6 cycles of acid challenge) were treated with dentifrices containing 1450 μg F(-)/g and HF3C (high fluoride dentifrice/3 cycles of acid challenge) and HF6C (high fluoride dentifrice/6 cycles of acid challenge) were with 5000 μg F(-)/g. Acid challenges were performed for seven days. After bond strength test, there was no significant difference among groups submitted to 3 cycles of acid challenge (P > 0.05). Statistically significant difference was found between the regular and high fluoride dentifrices after 6 cycles of acid challenge (<0.05). Similar areas of adhesive remaining were found among control groups and among groups W6C, RF3C, RF6C, HF3C, and HF6C. The high fluoride dentifrice was able to prevent the reduction of bond strength values of brackets submitted to acid challenge. the high fluoride toothpaste prevents debonded brackets on erosive enamel.

  13. Toothpaste Prevents Debonded Brackets on Erosive Enamel

    Directory of Open Access Journals (Sweden)

    Érico Luiz Damasceno Barros

    2015-01-01

    Full Text Available This study evaluated the effect of high fluoride dentifrice on the bond strength of brackets after erosive challenge. Eighty-four enamel specimens were divided into seven groups (n=12: WN (distilled water/no acid challenge, W3C (distilled water/3 cycles of acid challenge, and W6C (distilled water/6 cycles of acid challenge were not submitted to dentifrice treatment. Groups RF3C (regular fluoride dentifrice/3 cycles of acid challenge and RF6C (regular fluoride dentifrice/6 cycles of acid challenge were treated with dentifrices containing 1450 μg F−/g and HF3C (high fluoride dentifrice/3 cycles of acid challenge and HF6C (high fluoride dentifrice/6 cycles of acid challenge were with 5000 μg F−/g. Acid challenges were performed for seven days. After bond strength test, there was no significant difference among groups submitted to 3 cycles of acid challenge (P>0.05. Statistically significant difference was found between the regular and high fluoride dentifrices after 6 cycles of acid challenge (<0.05. Similar areas of adhesive remaining were found among control groups and among groups W6C, RF3C, RF6C, HF3C, and HF6C. The high fluoride dentifrice was able to prevent the reduction of bond strength values of brackets submitted to acid challenge. Clinical relevance: the high fluoride toothpaste prevents debonded brackets on erosive enamel.

  14. A method to detect soil carbon degradation during soil erosion

    Directory of Open Access Journals (Sweden)

    F. Conen

    2009-11-01

    Full Text Available Soil erosion has been discussed intensively but controversial both as a significant source or a significant sink of atmospheric carbon possibly explaining the gap in the global carbon budget. One of the major points of discussion has been whether or not carbon is degraded and mineralized to CO2 during detachment, transport and deposition of soil material. By combining the caesium-137 (137Cs approach (quantification of erosion rates with stable carbon isotope signatures (process indicator of mixing versus degradation of carbon pools we were able to show that degradation of carbon occurs during soil erosion processes at the investigated mountain grasslands in the central Swiss Alps (Urseren Valley, Canton Uri. Transects from upland (erosion source to wetland soils (erosion sinks of sites affected by sheet and land slide erosion were sampled. Analysis of 137Cs yielded an input of 2 and 4.6 tha−1 yr−1 of soil material into the wetlands sites. Assuming no degradation of soil organic carbon during detachment and transport, carbon isotope signature of soil organic carbon in the wetlands could only be explained with an assumed 500–600 and 350–400 years of erosion input into the wetlands Laui and Spissen, respectively. The latter is highly unlikely with alpine peat growth rates indicating that the upper horizons might have an age between 7 and 200 years. While we do not conclude from our data that eroded soil organic carbon is generally degraded during detachment and transport, we propose this method to gain more information on process dynamics during soil erosion from oxic upland to anoxic wetland soils, sediments or water bodies.

  15. On the geoethical implications of wind erosion

    Science.gov (United States)

    Károly, Tatárvári

    2016-04-01

    Human activities exerts an ever growing impact on our environment, and this is undeniably the responsibility of mankind. In spite of this fact there is almost no process in our environment that can be described exactly with complete exactness, and the working of which is known in full extent. Wind erosion is such a process. Although water erosion is mentioned ever more often in scientific circles as a from of erosion, its effect is restrained to a certain region, although it may cause perceptibly damage of a greater extent in short time. Wind erosion, apart from the fact that it may have global impact, may play an important role in the warming of our climate according to recent studies. First of all, wind erosion may cause damage far from its origin in human health, nutrition, or in the environment in general. Today several surveys have proved, that erosion caused by wind significantly contributes to the air pollution of cities, the fine dust carried as drift by the wind may cause severe environmental damage in accumulation zones. Microbes, toxic material may attach themselves to the dust carried this way and carried on and by the wings of the wind they may cause health issues in humans animals and plants as well. In spite of these facts there are almost no measures against wind erosion employed in arable land, although our ever doughtier climate and changes would make these necessary. Reduction of organic matter content presents a great problem in a large part of cultivated land, so the risk of the production of high quality food raises questions of more and more ethical nature. Who is responsible? The fact, that the chemicals used in a growing extent by agriculture may reach many people causing considerable damage to the environment also raises serious ethical questions. More and more periods with extreme weather conditions are experienced in Hungary and Europe as the effect of climate change. Drought periods are longer and more frequent as the intensity of

  16. Soil Erosion as a stochastic process

    Science.gov (United States)

    Casper, Markus C.

    2015-04-01

    corrected experimentally. To overcome this disadvantage of our actual models, soil erosion models are needed that are able to use stochastic directly variables and parameter distributions. There are only some minor approaches in this direction. The most advanced is the model "STOSEM" proposed by Sidorchuk in 2005. In this model, only a small part of the soil erosion processes is described, the aggregate detachment and the aggregate transport by flowing water. The concept is highly simplified, for example, many parameters are temporally invariant. Nevertheless, the main problem is that our existing measurements and experiments are not geared to provide stochastic parameters (e.g. as probability density functions); in the best case they deliver a statistical validation of the mean values. Again, we get effective parameters, spatially and temporally averaged. There is an urgent need for laboratory and field experiments on overland flow structure, raindrop effects and erosion rate, which deliver information on spatial and temporal structure of soil and surface properties and processes.

  17. [Biological soil crust nitrogenase activity and its responses to hydro-thermic factors in different erosion regions on the Loess Plateau, China].

    Science.gov (United States)

    Ming, Jiao; Zhao, Yun-Ge; Xu, Ming-Xiang; Yang, Li-Na; Wang, Ai-Guo

    2013-07-01

    Based on field survey, the biological soil crusts at their stable development stage were collected from the water erosion region, water-wind erosion region, and wind erosion region on the Loess Plateau, aimed to study the effects of the variations of moisture and temperature on the crusts nitrogenase activity (NA). The NA of the crusts in the erosion regions decreased in the order of water erosion region (127.7 micromol x m(-2) x h(-1)) > water-wind erosion region (34.6 micromol x m(-2) x h(-1)) > wind erosion region (6.0 micromol x m(-2) x h(-1)), and the optimal temperature for the crust nitrogen fixation was 35 degrees C, 25 degrees C, and 15 degrees C, respectively. At the optimal temperature and 100% -40% field water-holding capacity, the NA of the crusts from the water erosion and water-wind erosion regions had no significant difference. The NA of the crusts from the wind erosion region was more sensitive to the variation of moisture, showing a dramatic decline when the moisture decreased to 80% field water-holding capacity, and totally lost when the moisture decreased to 20% field water-holding capacity. The differences in the NA of the crusts from the three erosion regions and the responses of the NA to the variations of moisture and temperature were likely associated with the climate, environment, and the crust species composition.

  18. FORECAST THE SOIL EROSION THROUGH THE CARTOGRAMS

    OpenAIRE

    Mădălina - Cristina Marian

    2014-01-01

    Soil erosion in Arges County affects a high percentage of agricultural land. Most agricultural lands are located on slopes undergoing erosion, excess humidity temporarily or permanently, landslides. The importance lies in the need to know theme addressed erosion, the erosive potential of the land, the causes and factors that led to the onset of erosion and its deployment at a accelerated rate and now, because the based on this knowledge to determine the effective measures to prevent and c...

  19. Physical erosion modelling of complex morphodynamics in the upper Val d'Orcia: a combination of EROSION 3D, UAV, SFM and CANUPO

    Science.gov (United States)

    Buchholz, Arno; Kaiser, Andreas; Neugirg, Fabian; Schindewolf, Marcus; Schmidt, Jürgen

    2017-04-01

    Throughout the Mediterranean Basin soil erosion is both a widely spread and a landscape shaping process. In order to increase the understanding of morphodynamics inside large Italian badland areas, so called Calanchi, the process based erosion model EROSION 3D was parameterized by artificial rainfall simulations, soil sampling and an UAV based high resolution digital elevation model. Vegetation structures were removed with the CANUPO-classifier in CloudCompare. The rainfall experiments proved to be a convenient but costly tool for deriving the model input parameters. While building up the model, different composition of the inhomogeneous soil surface was considered. A diverse behavior against erosion by water was observed. The results showed that the deposition surfaces of rotational or translational slides, besides calanco depth contour, tend to degrade. Although these deposits present a comparatively low bulk density, they reduce the infiltration due to soil surface clogging and cause less erosion resistances. The differential consideration of erosion sub-processes turns out as particularly challenging. The simulation of a reference year showed an annual soil export from the catchment of 43 t/ha, which corresponds to an average surface lowering of 3 mm. Sheet erosion represents an amount of about 5% of the total erosion of badlands. Furthermore, infiltration depth, amount of runoff, sediment concentration, and grain size composition of the deposits were calculated. This study makes a contribution to the understanding of denudation processes in Calanchi badlands. The presented process-based modeling of badlands is contributing a new aspect to erosion research.

  20. The new volumetric approach for field measurements of rill erosion

    Directory of Open Access Journals (Sweden)

    Veronika Sobotková

    2015-04-01

    the soil loss from the plot threatened of water erosion. The advantage of this equipment is its using during the vegetable season when the soil surface is overgrown with vegetation and crops are higher growth.

  1. Riparian erosion vulnerability model based on environmental features.

    Science.gov (United States)

    Botero-Acosta, Alejandra; Chu, Maria L; Guzman, Jorge A; Starks, Patrick J; Moriasi, Daniel N

    2017-12-01

    Riparian erosion is one of the major causes of sediment and contaminant load to streams, degradation of riparian wildlife habitats, and land loss hazards. Land and soil management practices are implemented as conservation and restoration measures to mitigate the environmental problems brought about by riparian erosion. This, however, requires the identification of vulnerable areas to soil erosion. Because of the complex interactions between the different mechanisms that govern soil erosion and the inherent uncertainties involved in quantifying these processes, assessing erosion vulnerability at the watershed scale is challenging. The main objective of this study was to develop a methodology to identify areas along the riparian zone that are susceptible to erosion. The methodology was developed by integrating the physically-based watershed model MIKE-SHE, to simulate water movement, and a habitat suitability model, MaxEnt, to quantify the probability of presences of elevation changes (i.e., erosion) across the watershed. The presences of elevation changes were estimated based on two LiDAR-based elevation datasets taken in 2009 and 2012. The changes in elevation were grouped into four categories: low (0.5 - 0.7 m), medium (0.7 - 1.0 m), high (1.0 - 1.7 m) and very high (1.7 - 5.9 m), considering each category as a studied "species". The categories' locations were then used as "species location" map in MaxEnt. The environmental features used as constraints to the presence of erosion were land cover, soil, stream power index, overland flow, lateral inflow, and discharge. The modeling framework was evaluated in the Fort Cobb Reservoir Experimental watershed in southcentral Oklahoma. Results showed that the most vulnerable areas for erosion were located at the upper riparian zones of the Cobb and Lake sub-watersheds. The main waterways of these sub-watersheds were also found to be prone to streambank erosion. Approximatively 80% of the riparian zone (streambank

  2. A methodology for testing the erosive potential of sports drinks.

    Science.gov (United States)

    Hooper, S M; Hughes, J A; Newcombe, R G; Addy, M; West, N X

    2005-04-01

    The aim of the study was to develop and test a methodology in situ, which simulated the consumption of sports drinks. A secondary aim was to assess the acceptability of the method to sedentary participants. To select the sports drink for the study in situ, five commercially available sports drinks were examined for erosive potential in vitro. The study in situ was a single centre, 2-period, 2-treatment crossover study to compare the erosive effect of a commercially available sports drink (Test), with that of mineral water (Control), over 10 day periods on 10 healthy volunteers. Subjects wore upper removable appliances containing two human enamel specimens from 9 a.m. to 5 p.m. The regimen of intake of the drinks was 350 ml in 10, 5-min rest, 650 ml in 25, 5-min rest, 500 ml in 10 and 5-min rest. Measurements of enamel loss were made on samples after 5 and 10 days by profilometry. The in situ study showed a statistically significant difference in erosive potential between the test and control beverages. No specimen exposed to the control beverage displayed appreciable erosion. Erosion occurred with the test drink, but to a variable degree between subjects. The subjects unanimously found the drinking regimen unpleasant. The sports drink caused significantly more erosion in situ than water and as seen in other studies, there was marked variation in susceptibility to erosion between subjects. The new drinking regimen was designed to simulate pre, during and post-exercise intake. Although all the sedentary subjects participating in this study reported that they found the volume of fluids consumed over a short period of time excessive it is unlikely that this would prove problematic in the exercise environment.

  3. Erosive potential of vitamin and vitamin+mineral effervescent tablets.

    Science.gov (United States)

    Wegehaupt, Florian J; Lunghi, Nancy; Hogger, Vanessa M G; Attin, Thomas

    2016-01-01

    The extrinsic sources for erosion-causing acids are primarily acidic beverages and foodstuffs. Effervescent tablets also contain organic acids (e.g. citric, tartaric, malic) in order to form carbon dioxide by contact with water – with the help of the carbonate salts of the tablets. To adequately inform patients about the possible erosive potential of effervescent tablets, this study was undertaken in order to investigate the erosive potential of effervescent tablets (ET), containing either a combination of vitamins and minerals or vitamins only, commercially available in Switzerland. One hundred and ninety-two bovine enamel samples were prepared and allocated to 16 groups (A–H and 1–8; n = 12/group). Samples were eroded (120 s/erosive cycle) in freshly prepared solutions (200 ml/12 samples) comprised of tap water and a supplement as follows: none (control groups, A and 1); vitamin+mineral ET: Qualite and Prix (B), Optisana (C), Well and Active (D), Actilife All in One (E), Berocca (F), Isostar (G) and Qualite and Prix Mg + Vit C (H); vitamin ET: Actilife-Multivitamin (2), Sunlife Vitamin C (3), Optisana Vitamin C (4), Optisana Multivitamin (5), Well and Active Multivitamin (6), Kneipp Vitamin C+Zink (7) and Sunlife Multivitamin (8). Enamel loss was measured using profilometry after 10 and 20 erosive cycles. For the vitamin+mineral ET, no loss was observed in groups B–E. Significantly highest enamel loss (mean ± SD) after 20 cycles was observed for Isostar (5.26 ± 0.76 µm) and Qualite and Prix Mg + Vit C (5.12 ± 0.67 µm). All vitamine ET showed erosive enamel loss. Significantly highest loss was observed for Sunlife Multivitamin (8.45 ± 1.08 µm), while the lowest loss was observed for Actilife-Multivitamin (5.61 ± 1.08 µm) after 20 cycles. Some of the tested effervescent tablets showed a considerable erosive potential and patients should be informed accordingly.

  4. Tolerable soil erosion in Europe

    Science.gov (United States)

    Verheijen, Frank; Jones, Bob; Rickson, Jane; Smith, Celina

    2010-05-01

    Soil loss by erosion has been identified as an important threat to soils in Europe* and is recognised as a contributing process to soil degradation and associated deterioration, or loss, of soil functioning. From a policy perspective, it is imperative to establish well-defined baseline values to evaluate soil erosion monitoring data against. For this purpose, accurate baseline values - i.e. tolerable soil loss - need to be differentiated at appropriate scales for monitoring and, ideally, should take soil functions and even changing environmental conditions into account. The concept of tolerable soil erosion has been interpreted in the scientific literature in two ways: i) maintaining the dynamic equilibrium of soil quantity, and ii) maintaining biomass production, at a location. The first interpretation ignores soil quality by focusing only on soil quantity. The second approach ignores many soil functions by focusing only on the biomass (particularly crop) production function of soil. Considering recognised soil functions, tolerable soil erosion may be defined as 'any mean annual cumulative (all erosion types combined) soil erosion rate at which a deterioration or loss of one or more soil functions does not occur'. Assumptions and problems of this definition will be discussed. Soil functions can generally be judged not to deteriorate as long as soil erosion does not exceed soil formation. At present, this assumption remains largely untested, but applying the precautionary principle appears to be a reasonable starting point. Considering soil formation rates by both weathering and dust deposition, it is estimated that for the majority of soil forming factors in most European situations, soil formation rates probably range from ca. 0.3 - 1.4 t ha-1 yr-1. Although the current agreement on these values seems relatively strong, how the variation within the range is spatially distributed across Europe and how this may be affected by climate, land use and land management

  5. A semi-empirical model to assess uncertainty of spatial patterns of erosion

    NARCIS (Netherlands)

    Sterk, G.; Vigiak, O.; Romanowicz, R.J.; Beven, K.J.

    2006-01-01

    Distributed erosion models are potentially good tools for locating soil sediment sources and guiding efficient Soil and Water Conservation (SWC) planning, but the uncertainty of model predictions may be high. In this study, the distribution of erosion within a catchment was predicted with a

  6. Testing compost as an anti wind erosion agent in a wind tunnel

    NARCIS (Netherlands)

    Vos, de J.A.

    1996-01-01

    The potential of compost as an anti wind erosion agent was studied in a wind tunnel on a sandy soil susceptible to wind erosion. Soil treated with a compost-water mixture, which forms a crust on the soil surface after drying, was exposed to a series of increasing wind speeds. Two composts were

  7. Terrace effects on soil erosion processes in a watershed of the loess plateau

    Science.gov (United States)

    Terraces in crop fields are one of the most important soil and water conservation measures that affect runoff and erosion processes in a watershed. In this paper, terrace effects on soil erosion and sediment transport in the upstream and middle sections of the Weihe River basin in the Loess Plateau ...

  8. Evaluating ephemeral gully erosion impact on Zea mays L. yield and economics using AnnAGNPS

    Science.gov (United States)

    Ephemeral gully erosion causes serious water quality and economic problems in the Midwest United States. A critical barrier to soil conservation practice adoption is often the implementation cost, although it is recognized that erosion reduces farm income. Yet few, if any, understand the relationshi...

  9. Ex-post evaluation of erosion control measures in southern Mali

    NARCIS (Netherlands)

    Bodnar, F.; Spaan, W.P.; Hulshof, J.

    2007-01-01

    As part of an impact study of a soil and water conservation (SWC) project in southern Mali, the effect of erosion control measures on soil erosion was evaluated. In one village, a baseline situation from 1988 was compared with the situation in 2003, after farmers had installed stone rows, live

  10. Hillslope erosion rates in the oak savannas of the southwestern borderlands region

    Science.gov (United States)

    Aaron T. Kauffman; Cody L. Stropki; Peter F. Ffolliott; Gerald J. Gottfried; Daniel G. Neary

    2007-01-01

    Hillslope soil erosion on watershed landscapes can lower the productivity of upland sites and adversely impact water quality and downstream (off-site) areas. It is not surprising, therefore, that excessive soil erosion and the consequent sedimentation can represent significant costs to the land and people that are affected. The first known estimates of hillslope soil...

  11. Thermal erosion of a permafrost coastline: Improving process-based models using time-lapse photography

    Science.gov (United States)

    Wobus, C.; Anderson, R.; Overeem, I.; Matell, N.; Clow, G.; Urban, F.

    2011-01-01

    Coastal erosion rates locally exceeding 30 m y-1 have been documented along Alaska's Beaufort Sea coastline, and a number of studies suggest that these erosion rates have accelerated as a result of climate change. However, a lack of direct observational evidence has limited our progress in quantifying the specific processes that connect climate change to coastal erosion rates in the Arctic. In particular, while longer ice-free periods are likely to lead to both warmer surface waters and longer fetch, the relative roles of thermal and mechanical (wave) erosion in driving coastal retreat have not been comprehensively quantified. We focus on a permafrost coastline in the northern National Petroleum Reserve-Alaska (NPR-A), where coastal erosion rates have averaged 10-15 m y-1 over two years of direct monitoring. We take advantage of these extraordinary rates of coastal erosion to observe and quantify coastal erosion directly via time-lapse photography in combination with meteorological observations. Our observations indicate that the erosion of these bluffs is largely thermally driven, but that surface winds play a crucial role in exposing the frozen bluffs to the radiatively warmed seawater that drives melting of interstitial ice. To first order, erosion in this setting can be modeled using formulations developed to describe iceberg deterioration in the open ocean. These simple models provide a conceptual framework for evaluating how climate-induced changes in thermal and wave energy might influence future erosion rates in this setting.

  12. The prevalence of dental erosion in 5-year-old preschoolers in Sharjah, United Arab Emirates.

    Science.gov (United States)

    Gopinath, Vellore Kannan

    2016-01-01

    The aim of this study was to determine the percentage of 5-year-old preschoolers in Sharjah, affected by dental erosion and to assess the predictors. A total of 403 5-year-old children were examined of which 48.14% (n = 194) were boys and 51.86% (n = 209) were girls; 31.27% (n = 126) were Emirati and 68.73% (n = 277) were non-Emirati Arabs. Examination of dental erosion was confined to palatal surfaces of maxillary incisors using the erosion index described in the UK National Survey of Children's Dental Health, 1993. Dental caries was charted using the World Health Organization 1997 criteria. In the sample of 403 5-year-old preschoolers examined, dental erosion was apparent in 237 (58.80%) children, with 55.09% showing the dissolution of enamel and 3.72% exhibiting exposed dentin. Predictors of dental erosion as determined by logistic regression concluded that compared to Emirati citizens other Arab nationalities have 0.27 times the odds (95% confidence interval [CI] =0.18-0.42) of having tooth erosion (P erosion compared to children with no caries experience (P erosion compared to children who drink water (P erosion. Caries experience and consumption of acidic drinks were associated with dental erosion.

  13. Identification of soils susceptible to risk erosion and with hight capacity of water storage Identificación de suelos susceptibles a riesgos de erosión y con mayor capacidad de almacenamiento de agua

    Directory of Open Access Journals (Sweden)

    Escobar Chalarca Carlos Alberto

    2007-09-01

    Full Text Available The investigation was carried out in seven methodological steps under integral approaches, holistic analysis, logical sequence, participation and simplicity. The following aspects were highlighted: Conceptualization and contextualizacion, soil sampling , data processing, data spacializatión of the information, identification of susceptible areas to risk erosion with higher capacity of water storage, management norms and socialization of the investigation. The methodological proposal was validated and adjusted by a case of study in the rural areas of Chicoral, watershed of the Bitaco river, Municipality of La Cumbre, Cauca Valley , Colombia. Using participation processes and agreement with the communities of the study area, the diagnostic of the causes and consequences that intervene in processes of physical soil degradation were reached. At the same time, the places with higher potentiality of water storage were localized. All of these factors are important for planning and rational use of the natural resources in a watershed.La investigación se basó en el desarrollo de siete etapas metodológicas con criterios de integralidad, análisis holístico, secuencia lógica, participación y sencillez, destacándose los siguientes aspectos: Conceptualización y contextualización, muestreo de suelos, procesamiento de la información, espacialización de la información, identificación de zonas susceptibles a riesgos de erosión y con mayor capacidad de almacenamiento de agua, recomendaciones de manejo y socialización de la investigación. La propuesta metodológica se validó y ajustó mediante un caso de estudio en la vereda Chicoral, subcuenca del río Bitaco, municipio de La Cumbre, Valle del Cauca, Colombia. Mediante procesos de participación y concertación con los actores socioeconómicos del área de estudio se lograron diagnosticar las causas

  14. Global rainfall erosivity assessment based on high-temporal resolution rainfall records.

    Science.gov (United States)

    Panagos, Panos; Borrelli, Pasquale; Meusburger, Katrin; Yu, Bofu; Klik, Andreas; Jae Lim, Kyoung; Yang, Jae E; Ni, Jinren; Miao, Chiyuan; Chattopadhyay, Nabansu; Sadeghi, Seyed Hamidreza; Hazbavi, Zeinab; Zabihi, Mohsen; Larionov, Gennady A; Krasnov, Sergey F; Gorobets, Andrey V; Levi, Yoav; Erpul, Gunay; Birkel, Christian; Hoyos, Natalia; Naipal, Victoria; Oliveira, Paulo Tarso S; Bonilla, Carlos A; Meddi, Mohamed; Nel, Werner; Al Dashti, Hassan; Boni, Martino; Diodato, Nazzareno; Van Oost, Kristof; Nearing, Mark; Ballabio, Cristiano

    2017-06-23

    The exposure of the Earth's surface to the energetic input of rainfall is one of the key factors controlling water erosion. While water erosion is identified as the most serious cause of soil degradation globally, global patterns of rainfall erosivity remain poorly quantified and estimates have large uncertainties. This hampers the implementation of effective soil degradation mitigation and restoration strategies. Quantifying rainfall erosivity is challenging as it requires high temporal resolution(<30 min) and high fidelity rainfall recordings. We present the results of an extensive global data collection effort whereby we estimated rainfall erosivity for 3,625 stations covering 63 countries. This first ever Global Rainfall Erosivity Database was used to develop a global erosivity map at 30 arc-seconds(~1 km) based on a Gaussian Process Regression(GPR). Globally, the mean rainfall erosivity was estimated to be 2,190 MJ mm ha-1 h-1 yr-1, with the highest values in South America and the Caribbean countries, Central east Africa and South east Asia. The lowest values are mainly found in Canada, the Russian Federation, Northern Europe, Northern Africa and the Middle East. The tropical climate zone has the highest mean rainfall erosivity followed by the temperate whereas the lowest mean was estimated in the cold climate zone.

  15. [Tooth erosion - a multidisciplinary approach].

    Science.gov (United States)

    Strużycka, Izabela; Rusyan, Ewa; Bogusławska-Kapała, Agnieszka

    2016-02-01

    During the last decades, an increasingly greater interest in dental erosion has been observed in clinical dental practice, in dental public health and in dental research because prevalence of erosive tooth wear is still increasing especially in young age group of population. Erosive tooth wear is a multifactorial etiology process characterized by progressive loss of hard dental tissue. It is defined as the exogenous and/or endogenous acids dissolution of the dental tissue, without bacterial involvement. In the development of dental erosive wear, interactions are required which include chemical, biological, behavioral, diet, time, socioeconomic, knowledge, education, and general health factors. Examples of risk groups could be patients with eating disorders, like anorexia nervosa or bulimia nervosa, gastroesophageal reflux disease, chronic alcohol abuse or dependence. Special nutrition habits groups with high consumption of soft or sport drinks, special diets like vegetarian, vegan or raw food diet, the regular intake of drugs, medications and food supplements can also increase the risk for dental erosion. Comprehensive knowledge of the different risk and protective factors is a perquisite for initiating adequate preventive measures. © 2016 MEDPRESS.

  16. The costs of soil erosion

    Directory of Open Access Journals (Sweden)

    Tiago Santos Telles

    2011-04-01

    Full Text Available The aim of this study was a survey of the estimated costs of soil erosion, an issue of fundamental importance in view of the current worldwide discussions on sustainability. A list was drawn up of research papers on erosion (on-site and off-site effects and their respective costs. The estimates indicate the amount of resources spent in the process of soil degradation, raising a general awareness of the need for soil conservation. On-site costs affect the production units directly, while off-site costs create a burden borne by the environment, economy and society. In addition, estimating the costs of soil erosion should be effective to alert the agricultural producers, society and government for the need for measures that can be implemented to bring erosion under control. Among the various estimates of soil erosion costs between 1933 a 2010, the highest figure was 45.5 billion dollars a year for the European Union. In the United States, the highest figure was 44 billion dollars a year. In Brazil, estimates for the state of Paraná indicate a value of 242 million dollars a year, and for the state of São Paulo, 212 million dollars a year. These figures show, above all, that conservation measures must be implemented if crop and livestock farming production are to be sustainable.

  17. THE EVALUATION OF SOIL EROSION OFF-SITES EFFECTS IN LARGE BASINS: THE STUDYCASE OF LERMA-CHAPALA WATERSHED, MEXICO

    OpenAIRE

    Helena Cotler A.; Susana Gutierrez D.; Carlos Enriquez G.; Arturo Garrido P.

    2005-01-01

    One of the primary global concerns during the new millennium is the assessment of the impact of accelerated soil erosion on the economy and the environment (Pimentel et al. 1995; Lal, 1995). Erosion damages the site on which it occurs and also has undesirable effects off-site in the larger environment. Erosion moves sediments and nutrients out of the land, creating the two most widespread water pollution problems in the rivers, lakes and dams. The nutrients impact water quality largely throug...

  18. Accelerated rain erosion of wind turbine blade coatings

    DEFF Research Database (Denmark)

    Zhang, Shizhong

    of the new setup with the whirling arm rig, a dimensional analysis was conducted and experiments with two polyurethane-based blade coatings carried out. Results showed that water jet slug velocity and impact frequency are the most influential parameters on the coating erosion rate. Furthermore, very small...

  19. Reduction of erosion by protein-containing toothpastes

    NARCIS (Netherlands)

    Jager, D.H.; Vissink, A.; Timmer, C.J.; Bronkhorst, E.M.; Vieira, A.M.; Huysmans, M.C.D.N.J.M.

    2013-01-01

    AIM: To assess the effect of protein-containing toothpastes on the progression of dental erosion in situ (with pellicle) and in vitro (without pellicle). METHODS: A combined split-mouth (extraoral water or toothpaste brushing) and crossover (type of toothpaste) setup was used. Two protein-containing

  20. Reduction of Erosion by Protein-Containing Toothpastes

    NARCIS (Netherlands)

    Jager, D. H. J.; Vissink, A.; Timmer, C. J.; Bronkhorst, E.; Vieira, A. M.; Huysmans, M. C. D. N. J. M.

    2013-01-01

    Aim: To assess the effect of protein-containing toothpastes on the progression of dental erosion in situ (with pellicle) and in vitro (without pellicle). Methods: A combined split-mouth (extraoral water or toothpaste brushing) and crossover (type of toothpaste) setup was used. Two protein-containing

  1. Evaluation of erosion and sedimentation associated with tracked vehicle training

    Science.gov (United States)

    Jackie F. Crim; Jon E. Schoonover; Karl W.J. Williard; John W. Groninger; James J. Zaczek; Charles M. Ruffner

    2011-01-01

    A project was designed to assess erosion and sedimentation associated with tracked vehicle training in the Ft. Knox Military Reservation in Kentucky. The project provided an extensive physical and biotic characterization of the training area, including hydrology, water quality, soils, and vegetation. To determine any changes in channel morphology, cross sections were...

  2. Water erosion in soils under eucalyptus forest as affected by development stages and management systems Erosão hídrica em solos sob floresta de eucalipto em diferentes estádios de desenvolvimento e sistemas de manejo

    Directory of Open Access Journals (Sweden)

    Anna Hoffmann Oliveira

    2013-04-01

    Full Text Available The constant increasing of eucalyptus forest areas in Brazil requires an accurate monitoring of water erosion. The present study aimed to evaluate soil, nutrients and organic carbon losses occasioned by water erosion in eucalyptus planted forests (EPF at different development stages (2, 3 and 7 years old. Soil erosion sediments were measured and sampled from standard erosion plots installed on Red Argisol-RA (Ultisol and Haplic Cambisol-HC (Inceptisol. Soil loss decreased as the age of plants increased; at the beginning of plant development, the canopy barely covered the soil surface, exposing the soil to higher erosion at young EPF plantations. Furrow planting system was used in the Red Argisol area and caused higher soil losses (1.1 to 6.2 Mg ha-1 year-1 as compared to pit planting system that was used in the Cambisol area (1.1 Mg ha-1 year-1. It is known that Cambisol is less resistant to erosion than Argisol. However, using pit system in this EPF, resulted in lower erosion and, therefore, nutrients and carbon losses than the traditional furrow system used in Argisol. Concerning the soil loss, this work points to the need of improving soil conservation practices to prevent soil erosion at the earlier stages of eucalyptus plantation. The amount of calcium and potassium were higher than magnesium in the soil sediment.The relatively high amount of carbon found in the erosion sediments raises additional concerns about the environmental sustainability and deserves future research.O aumento constante das áreas de florestas de eucalipto no Brasil impõe um monitoramento acurado da erosão hídrica. No presente estudo, objetivou-se avaliar as perdas de solo, nutrientes e carbono orgânico ocasionadas pela erosão hídrica em florestas plantadas de eucalipto em diferentes estádios de desenvolvimento (2, 3 e 7 anos. Os sedimentos de erosão foram medidos e amostrados por parcelas-padrão instaladas em Argissolo Vermelho (Ultisol e Cambissolo H

  3. Soil erosion in Slovene Istria

    Directory of Open Access Journals (Sweden)

    Matjaž Mikoš

    2009-12-01

    Full Text Available From the end of nineties of the 20th century, intense hydrologic and geomorphologic research is taking place in the Slovene Istria. As a part of this research also studies on soil erosion were undertaken in the period from 2005 to 2008. The field measurements were under taken onclosed 1m2 large erosion plots under three different land uses (on bare soils in an olive grove, on an overgrown meadow, in a forest, placed south of the Marezige village in the Rokava River basin.We show weekly measurements of surface erosion (interrill erosion for the period of 13 months (the end of March 2005 – the end of April 2006, as well as monthly and seasonal averages together with selected linear statistical correlations between soil erosion and weather parameters.From May 2005 to April 2006 the interrill erosion on bare soils in an olive grove with an inclination of 5.5° amounted to 9013 g/m2 (90 t/ha that corresponds to surface lowering rate of 8.5 mm/yr; on an overgrown meadow with an inclination of 9.4° it amounted to 168 g/m2 (1,68 t/ha that corresponds to surface lowering rate of 0.16 mm//yr; and in a forest with an inclination of 7.8° it amounted to 391 g/m2 (3,91 t/ha and in a forest with an inclination of 21.4° it amounted to 415 g/m2 (4,15 t/ha, respectively, that corresponds to surface lowering rate of 0.4 mm/yr.

  4. DISPERSION OF GLYPHOSATE IN SOILS UNDERGOING EROSION

    Directory of Open Access Journals (Sweden)

    Gorana Todorovic Rampazzo

    2010-08-01

    Full Text Available Different physical, chemical and biological processes influence the behaviour of organic contaminants in soils. A better understanding of the organic pollutant behaviour in soils would improve the environmental protection. One possible way for better attenuation of the risk of pollution in agriculture can be achieved through ta better-specified pesticide management based on the adaptation of the pesticide type and application rates to the specific environmental characteristics of the area of application. Nowadays, one of the actually most applied herbicide world wide is glyphosate. Glyphosate is highly water soluble and traces have been found in surface and groundwater systems. For a better understanding of the natural influence of erosion processes on glyphosate behaviour and dispersion under heavy rain conditions after application in the field, two erosion simulation experiments were conducted on two different locations in Austria with completely different soil types in September 2008. The results of the experiments showed that under normal practical conditions (e.g. no rainfall is expected immediatly after application, the potential adsorption capacity of the Kirchberg soil (Stagnic Cambisol, with about 16.000 ppm Fe-oxides is confirmed compared to the low adsorption Chernosem soil (about 8.000 ppm pedogenic Fe-oxides.  Considering the enormous difference in the run-off amounts between the two sites Pixendorf and Kirchberg soils it can be concluded how important the soil structural conditions and vegetation type and cover are for the risks of erosion and, as a consequence, pollution of neighbouring waters. In the rainfall experiments under comparable simulation conditions, the amount of run-off was about 10 times higher at Kirchberg, owing to its better infiltration rate, than at the Pixendorf site. Moreover, the total loss of glyphosate (NT+CT through run-off at the Kirchberg site was more than double that at Pixendorf, which confirms the

  5. Determination of riverbank erosion probability using Locally Weighted Logistic Regression

    Science.gov (United States)

    Ioannidou, Elena; Flori, Aikaterini; Varouchakis, Emmanouil A.; Giannakis, Georgios; Vozinaki, Anthi Eirini K.; Karatzas, George P.; Nikolaidis, Nikolaos

    2015-04-01

    erosion occurrence probability can be calculated in conjunction with the model deviance regarding the independent variables tested. The most straightforward measure for goodness of fit is the G statistic. It is a simple and effective way to study and evaluate the Logistic Regression model efficiency and the reliability of each independent variable. The developed statistical model is applied to the Koiliaris River Basin on the island of Crete, Greece. Two datasets of river bank slope, river cross-section width and indications of erosion were available for the analysis (12 and 8 locations). Two different types of spatial dependence functions, exponential and tricubic, were examined to determine the local spatial dependence of the independent variables at the measurement locations. The results show a significant improvement when the tricubic function is applied as the erosion probability is accurately predicted at all eight validation locations. Results for the model deviance show that cross-section width is more important than bank slope in the estimation of erosion probability along the Koiliaris riverbanks. The proposed statistical model is a useful tool that quantifies the erosion probability along the riverbanks and can be used to assist managing erosion and flooding events. Acknowledgements This work is part of an on-going THALES project (CYBERSENSORS - High Frequency Monitoring System for Integrated Water Resources Management of Rivers). The project has been co-financed by the European Union (European Social Fund - ESF) and Greek national funds through the Operational Program "Education and Lifelong Learning" of the National Strategic Reference Framework (NSRF) - Research Funding Program: THALES. Investing in knowledge society through the European Social Fund.

  6. Grazing and soil erosion in dehesas of SW Spain

    Energy Technology Data Exchange (ETDEWEB)

    Schnabel, S.; Gomez Gutierrez, A.; Lavado Contador, J. L.

    2009-07-01

    Water erosion and its relation to livestock grazing in semi-arid to dry sub humid Mediterranean rangelands with a disperse tree cover is analyzed, based on a variety of studies carried out since 1990 in Extremadure, Spain. The dominant factors of sheet wash are rainfall intensity and soil surface cover, the latter being controlled by rainfall amounts and livestock density. The discontinuous valley bottom gullies present a complex relationship with catchment hydrology. giving the high temporal variability of sediment losses, the influence of livestock on gully erosion is difficult to determine with short-tern studied. (Author) 4 refs.

  7. Application of spatial Markov chains to the analysis of the temporal-spatial evolution of soil erosion.

    Science.gov (United States)

    Liu, Ruimin; Men, Cong; Wang, Xiujuan; Xu, Fei; Yu, Wenwen

    Soil and water conservation in the Three Gorges Reservoir Area of China is important, and soil erosion is a significant issue. In the present study, spatial Markov chains were applied to explore the impacts of the regional context on soil erosion in the Xiangxi River watershed, and Thematic Mapper remote sensing data from 1999 and 2007 were employed. The results indicated that the observed changes in soil erosion were closely related to the soil erosion levels of the surrounding areas. When neighboring regions were not considered, the probability that moderate erosion transformed into slight and severe erosion was 0.8330 and 0.0049, respectively. However, when neighboring regions that displayed intensive erosion were considered, the probabilities were 0.2454 and 0.7513, respectively. Moreover, the different levels of soil erosion in neighboring regions played different roles in soil erosion. If the erosion levels in the neighboring region were lower, the probability of a high erosion class transferring to a lower level was relatively high. In contrast, if erosion levels in the neighboring region were higher, the probability was lower. The results of the present study provide important information for the planning and implementation of soil conservation measures in the study area.

  8. Mechanisms of erosion in miocene clays from the Tudela formation (Bardenas Reales, Navarra, Spain); Mecanismos de erosion en arcillas miocenas de la Formacion Tudela (Bardenas Reales, Navarra, Espana)

    Energy Technology Data Exchange (ETDEWEB)

    Marin, C.; Desir, G.

    2009-07-01

    In Bardenas Reales area (located in the central-western part of the Ebro Depression) several erosion rates have been measured along the last years. The mean annual erosion rates are of 32 Tm/Ha/yr. Due to semiarid conditions, precipitation is irregularly distributed along the year with maximums on spring and autumn when the great erosion is produced. There are intensity and quality thresholds below which erosion does not take place. In Bardenas Reales some erosion processes act (mud slides and armoured mud balls among others). Mud slides are mobilised on spring when the sediment have reached its plastic limit and could slide due to heavy rains. Armored mud balls are produced by the enhancement of popcorn cracks that individualize clays cores which are rounded by water. The same kind of strong precipitation that mobilised mud slides is the responsible of armoured mud balls destruction because the conditions to its maintenance are very limited. (Author) 9 refs.

  9. Seasonal variation and climate change impact in Rainfall Erosivity across Europe

    Science.gov (United States)

    Panagos, Panos; Borrelli, Pasquale; Meusburger, Katrin; Alewell, Christine; Ballabio, Cristiano

    2017-04-01

    Rainfall erosivity quantifies the climatic effect on water erosion and is of high importance for soil scientists, land use planners, agronomists, hydrologists and environmental scientists in general. The rainfall erosivity combines the influence of rainfall duration, magnitude, frequency and intensity. Rainfall erosivity is calculated from a series of single storm events by multiplying the total storm kinetic energy with the measured maximum 30-minute rainfall intensity. This estimation requests high temporal resolution (e.g. 30 minutes) rainfall data for sufficiently long time periods (i.e. 20 years). The European Commission's Joint Research Centr(JRC) in collaboration with national/regional meteorological services and Environmental Institutions made an extensive data collection of high resolution rainfall data in the 28 Member States of the European Union plus Switzerland to estimate rainfall erosivity in Europe. This resulted in the Rainfall Erosivity Database on the European Scale (REDES) which included 1,675 stations. The interpolation of those point erosivity values with a Gaussian Process Regression (GPR) model has resulted in the first Rainfall Erosivity map of Europe (Science of the Total Environment, 511: 801-815). In 2016, REDES extended with a monthly component, which allowed developing monthly and seasonal erosivity maps and assessing rainfall erosivity both spatially and temporally for European Union and Switzerland. The monthly erosivity maps have been used to develop composite indicators that map both intra-annual variability and concentration of erosive events (Science of the Total Environment, 579: 1298-1315). Consequently, spatio-temporal mapping of rainfall erosivity permits to identify the months and the areas with highest risk of soil loss where conservation measures should be applied in different seasons of the year. Finally, the identification of the most erosive month allows recommending certain agricultural management practices (crop

  10. Modelling soil carbon fate under erosion process in vineyard

    Science.gov (United States)

    Novara, Agata; Scalenghe, Riccardo; Minacapilli, Mario; Maltese, Antonino; Capodici, Fulvio; Borgogno Mondino, Enrico; Gristina, Luciano

    2017-04-01

    Soil erosion processes in vineyards beyond water runoff and sediment transport have a strong effect on soil organic carbon loss (SOC) and redistribution along the slope. The variation of SOC across the landscape determines a difference in soil fertility and vine productivity. The aim of this research was to study erosion of a Mediterranean vineyard, develop an approach to estimate the SOC loss, correlate the vines vigor with sediment and carbon erosion. The study was carried out in a Sicilian (Italy) vineyard, planted in 2011. Along the slope, six pedons were studied by digging 6 pits up to 60cm depth. Soil was sampled in each pedon every 10cm and SOC was analyzed. Soil erosion, detachment and deposition areas were measured by pole height method. The vigor of vegetation was expressed in term of NDVI (Normalized difference Vegetation Index) derived from a satellite image (RapidEye) acquired at berry pre-veraison stage (July) and characterized by 5 spectral bands in the shortwave region, including a band in the red wavelength (R, 630-685 nm) and in the near infrared (NIR, 760-850 nm) . Results showed that soil erosion, sediments redistribution and SOC across the hill was strongly affected by topographic features, slope and curvature. The erosion rate was 46Mg ha-1 y-1 during the first 6 years since planting. The SOC redistribution was strongly correlated with the detachment or deposition area as highlighted by pole height measurements. The approach developed to estimate the SOC loss showed that during the whole study period the off-farm SOC amounts to 1.6Mg C ha-1. As highlighted by NDVI results, the plant vigor is strong correlated with SOC content and therefore, developing an accurate NDVI approach could be useful to detect the vineyard areas characterized by low fertility due to erosion process.

  11. Determination of soil erosion and sedimentation affected by buffer zones and biochar amendment as best management practices

    DEFF Research Database (Denmark)

    Khademalrasoul, Ataalah

    ) to improve soil structural properties in order to lowering the erodibility of the soil. A second objective was to parameterize a spatially distributed erosion model (WaTEM, Water and Tillage Erosion Model) for planning of the placement of buffer zones (a structural BMP) to reduce sediment transport to water...

  12. Erosion in the juniata river drainage basin, Pennsylvania

    Science.gov (United States)

    Sevon, W.D.

    1989-01-01

    Previously calculated erosion rates througouth the Appalachians range from 1.2 to 203 m Myr-1. Calculation of erosion rates has been accomplished by: (1) evaluation of riverine solute and sediment load in either large or small drainage basins; (2) estimation from the volume of derived sediments; and (3) methods involving either 10Be or fission-track dating. Values of specific conductance and suspended sediment collected at the Juniata River gauging station at Newport, Pennsylvania are used, with corrections, along with a bedload estimate to determine the total amount eroded from the 8687 km2 drainage basin during the water years 1965-1986. The amount eroded is used to calculate a present erosion rate of 27 m Myr-1. ?? 1989.

  13. Changes in water budgets and sediment yields from a hypothetical agricultural field as a function of landscape and management characteristics--A unit field modeling approach

    Science.gov (United States)

    Roth, Jason L.; Capel, Paul D.

    2012-01-01

    Crop agriculture occupies 13 percent of the conterminous United States. Agricultural management practices, such as crop and tillage types, affect the hydrologic flow paths through the landscape. Some agricultural practices, such as drainage and irrigation, create entirely new hydrologic flow paths upon the landscapes where they are implemented. These hydrologic changes can affect the magnitude and partitioning of water budgets and sediment erosion. Given the wide degree of variability amongst agricultural settings, changes in the magnitudes of hydrologic flow paths and sediment erosion induced by agricultural management practices commonly are difficult to characterize, quantify, and compare using only field observations. The Water Erosion Prediction Project (WEPP) model was used to simulate two landscape characteristics (slope and soil texture) and three agricultural management practices (land cover/crop type, tillage type, and selected agricultural land management practices) to evaluate their effects on the water budgets of and sediment yield from agricultural lands. An array of sixty-eight 60-year simulations were run, each representing a distinct natural or agricultural scenario with various slopes, soil textures, crop or land cover types, tillage types, and select agricultural management practices on an isolated 16.2-hectare field. Simulations were made to represent two common agricultural climate regimes: arid with sprinkler irrigation and humid. These climate regimes were constructed with actual climate and irrigation data. The results of these simulations demonstrate the magnitudes of potential changes in water budgets and sediment yields from lands as a result of landscape characteristics and agricultural practices adopted on them. These simulations showed that variations in landscape characteristics, such as slope and soil type, had appreciable effects on water budgets and sediment yields. As slopes increased, sediment yields increased in both the arid and

  14. Integrated spatial assessment of wind erosion risk in Hungary

    Directory of Open Access Journals (Sweden)

    L. Pásztor

    2016-11-01

    Full Text Available Wind erosion susceptibility of Hungarian soils was mapped on the national level integrating three factors of the complex phenomenon of deflation (physical soil features, wind characteristics, and land use and land cover. Results of wind tunnel experiments on erodibility of representative soil samples were used for the parametrization of a countrywide map of soil texture compiled for the upper 5 cm layer of soil, which resulted in a map representing threshold wind velocity exceedance. Average wind velocity was spatially estimated with 0.5′ resolution using the Meteorological Interpolation based on Surface Homogenised Data Basis (MISH method elaborated for the spatial interpolation of surface meteorological elements. The probability of threshold wind velocity exceedance was determined based on values predicted by the soil texture map at the grid locations. Ratio values were further interpolated to a finer 1 ha resolution using sand and silt content of the uppermost (0–5 cm layer of soil as spatial co-variables. Land cover was also taken into account, excluding areas that are not relevant to wind erosion (forests, water bodies, settlements, etc., to spatially assess the risk of wind erosion. According to the resulting map of wind erosion susceptibility, about 10 % of the total area of Hungary can be identified as susceptible to wind erosion. The map gives more detailed insight into the spatial distribution of wind-affected areas in Hungary compared to previous studies.

  15. Soil erosion assessment and control in Northeast Wollega, Ethiopia

    Science.gov (United States)

    Adugna, A.; Abegaz, A.; Cerdà, A.

    2015-12-01

    Soil erosion is the main driver of land degradation in Ethiopia, and in the whole region of East Africa. This study was conducted at the Northeast Wollega in West Ethiopia to estimate the soil losses by means of the Revised Universal Soil Loss Equation (RUSLE). The purpose of this paper is to identify erosion spot areas and target locations for appropriate development of soil and water conservation measures. Fieldwork and household survey were conducted to identify major determinants of soil erosion control. Six principal factors were used to calculate soil loss per year, such as rainfallerosivity, soil erodiblity, slope length, slope steepness, crop management and erosion-control practices. The soil losses have shown spatio-temporal variations that range from 4.5 Mg ha-1 yr-1 in forest to 65.9 Mg ha-1 yr-1 in cropland. Results from the analysis of stepwise multiple linear regression show that sustainable soil erosion control are determined byknowledge of farmers about soil conservation, land tenure security and off-farm income at community level. Thus, policy aim at keeping land productivity will need to focus on terracing, inter-cropping and improved agro-forestry practices.

  16. Integrated spatial assessment of wind erosion risk in Hungary

    Science.gov (United States)

    Pásztor, László; Négyesi, Gábor; Laborczi, Annamária; Kovács, Tamás; László, Elemér; Bihari, Zita

    2016-11-01

    Wind erosion susceptibility of Hungarian soils was mapped on the national level integrating three factors of the complex phenomenon of deflation (physical soil features, wind characteristics, and land use and land cover). Results of wind tunnel experiments on erodibility of representative soil samples were used for the parametrization of a countrywide map of soil texture compiled for the upper 5 cm layer of soil, which resulted in a map representing threshold wind velocity exceedance. Average wind velocity was spatially estimated with 0.5' resolution using the Meteorological Interpolation based on Surface Homogenised Data Basis (MISH) method elaborated for the spatial interpolation of surface meteorological elements. The probability of threshold wind velocity exceedance was determined based on values predicted by the soil texture map at the grid locations. Ratio values were further interpolated to a finer 1 ha resolution using sand and silt content of the uppermost (0-5 cm) layer of soil as spatial co-variables. Land cover was also taken into account, excluding areas that are not relevant to wind erosion (forests, water bodies, settlements, etc.), to spatially assess the risk of wind erosion. According to the resulting map of wind erosion susceptibility, about 10 % of the total area of Hungary can be identified as susceptible to wind erosion. The map gives more detailed insight into the spatial distribution of wind-affected areas in Hungary compared to previous studies.

  17. Assessment of soil erosion sensitivity and post-timber-harvesting erosion response in a mountain environment of Central Italy

    Science.gov (United States)

    Borrelli, Pasquale; Schütt, Brigitta

    2014-01-01

    This study aimed to assess the effects of forest management on the occurrence of accelerated soil erosion by water. The study site is located in a mountainous area of the Italian Central Apennines. Here, forest harvesting is a widespread forestry activity and is mainly performed on the moderate to steep slopes of the highlands. Through modeling operations based on data on soil properties and direct monitoring of changes in the post-forest-harvesting soil surface level at the hillslope scale, we show that the observed site became prone to soil erosion after human intervention. Indeed, the measured mean soil erosion rate of 49 t ha- 1 yr- 1 for the harvested watershed is about 21 times higher than the rate measured in its neighboring undisturbed forested watershed (2.3 t ha- 1 yr- 1). The erosive response is greatly aggravated by exposing the just-harvested forest, with very limited herbaceous plant cover, to the aggressive attack of the heaviest annual rainfall without adopting any conservation practices. The erosivity of the storms during the first four months of field measurements was 1571 MJ mm h- 1 ha- 1 in total (i.e., from September to December 2008). At the end of the experiment (16 months), 18.8%, 26.1% and 55.1% of the erosion monitoring sites in the harvested watershed recorded variations equal or greater than 0-5, 5-10 and > 10 mm, respectively. This study also provides a quantification of Italian forestland surfaces with the same pedo-lithological characteristics exploited for wood supply. Within a period of ten years (2002-2011), about 9891 ha of coppice forest changes were identified and their potential soil erosion rates modeled.

  18. WOTS Reservoir Erosion Control and Revegetation Workshop and Demonstration, Volume 1, No. 1

    National Research Council Canada - National Science Library

    Allen, Hollis

    1999-01-01

    ...) Program, many of these reservoirs have a considerable amount of shoreline erosion that can adversely impact aquatic and riparian habitats as well as numerous other factors, such as water quality...

  19. Gully erosion in Moldova: evolution, importance and control

    Science.gov (United States)

    Leah, Tamara

    2017-04-01

    Soil erosion and landslides are major environmental problems in the Republic of Moldova, resulting in long-term impacts on land productivity and sustainable development of rural areas. Soil erosion occurs on about 1.5 million hectares of agricultural land. Erosion possible limits on agricultural land range from 3 t/ha to 180 t/ha. The weighted average in the country is 18.5 t/ ha/year. But once in 50-100 years the mentioned limits may be exceeded. Combination the physical-geographical complicate conditions with intensive agricultural activities on the slopes led to the development of linear (depth) erosion, from initial sheet and rills to entire systems of gullies and ravines. Depth erosion affects most powerful the slope land (60%) of southern steppe and central silvo-steppe zones of Moldova. Gullies refers to erosion forms named "agrierosional", which forms most often on slopes with a length of 500 m and inclination greater than 3°, pants occupied with vineyards and orchards. Annually on these slopes are formed 700-800 new gullies, with length of 50-70 km and an area of 300 hectares. As a result of the inadequate soil cultivation the gullies parameters are increased, that concentrates water runoff, intensifies soil erosion, forming corrugation on the soil surface and increase land and environment degradation. The first gullies inventory in Moldova was carried out in 1911, the following in 1965 and 1982. After this period their area was annual included in the land cadastral sheet. If in the 1911 the total number of gullies made up 9543 with an area of 14434 hectares, in 1965 was increased on average by 3.5 times and in the southern areas more than 10 times. Gullies density of the republic made up in 1911 - 0.42 unites/km2, in 1965 increased by 3 times and in some districts by 5-6 times. After 1965, a part of the land affected by gullies was gradually transformed from farmland into forest resources. This measure contributed to significant changes in agricultural

  20. Fluvial processes on Mars: Erosion and sedimentation

    Science.gov (United States)

    Squyres, Steven W.

    1988-01-01

    One of the most important discoveries of the Mariner 9 and Viking missions to Mars was evidence of change of the Martian surface by the action of liquid water. From the standpoint of a Mars Rover/Sample Return Mission, fluvial activity on Mars is important in two ways: (1) channel formation has deeply eroded the Martian crust, providing access to relatively undisturbed subsurface units; and (2) much of the material eroded from channels may have been deposited in standing bodies of liquid water. The most striking fluvial erosion features on Mars are the outflow channels. A second type of channel apparently caused by flow of liquid water is the valley systems. These are similar to terrestial drainage systems. The sedimentary deposits of outflow channels are often difficult to identfy. No obvious deposits such as deltaic accumulations are visible in Viking images. Another set of deposits that may be water lain and that date approx. from the epoch of outflow channels are the layered deposits in the Valles Marineris. From the standpoint of a Mars Rover/Sample Return mission, the problem with all of these water-lain sediments is their age, or rather the lack of it.

  1. Uncertainties in assessing tillage erosion - how appropriate are our measuring techniques?

    Science.gov (United States)

    Fiener, Peter; Deumlich, Detlef; Gómez, José A.; Guzmán, Gema; Hardy, Robert; Jague, Emilien A.; Quinton, John; Sommer, Michael; van Oost, Kristof; Wexler, Robert; Wilken, Florian

    2017-04-01

    In undulating arable landscapes tillage erosion is one of the dominant processes initiating lateral transfer of soil and soil constituents. Especially, in relatively dry regions, where tillage erosion can be much larger than water erosion, the associated changes in soil hydraulic properties might have substantial effects upon the sustainable use of soil resources. There have been some studies using different techniques to determine tillage erosion which build the basis for tillage erosion modelling approaches. However, tillage erosion is rather understudied compared to water erosion. The goal of this study was to bring together experts using different techniques to determine tillage erosion in an experimental set-up and to analyse the different results and assess the uncertainties associated with typical model inputs. Tillage erosion on a 50 x 10 m plot was determined after two phases of seven tillage passes performed within a week (simulating 10-14 yrs of tillage). As tracers, two different micro-tracers (magnetite mixed with soil and fluorescent sand) and one macro-tracer (passive Radio-Frequency Identification (RFID) transponders; dia. 3 mm, length 20 mm) were used. Moreover, tillage induced changes in topography were spatially determined for the entire plot with two different terrestrial laser scanners and an UAV-based structure by motion topography analysis. Topography changes were also evaluated at 12 points using buried concrete flagstones as reference. A preliminary analysis of tracer movement indicates substantial differences in tillage induced translocation depending on type of tracer. While the mean translocation of the RFIDs was 0.47 m per pass the mean movement of the micro-tracers was 0.70 m. Substantial differences were also found for the different techniques to determine changes in topography. Overall the experiment underlines the importance of tillage erosion for the lateral transfer of soil and soil constituents, but also shows the large

  2. Model-based assessment of erosion risks on man-made slopes in recultivation areas

    Science.gov (United States)

    Kunth, F.; Schmidt, J.

    2012-04-01

    The present study deals with non-vegetated slopes of post mining areas which are heavily endangered by soil erosion by water. The prevention of massive on-site damages as well as off-site effects by the emission of acid dump materials is one of the major challenges in the context of recultivation of closed-down open cast mining areas. Hence, the aim of this study is the development of a reproducible methodology to determine erosion risks on slopes in recultivation areas. Moreover, a standardised technique is developed to plan, dimension and test erosion protection measures in recultivation landscapes. The analyses of the study are based on the event-based physical erosion model EROSION 3D. The widely used model is able to predict runoff as well as detachment, transport and deposition of sediments. Its use and validation ranges from erosion prediction from agricultural land to sediment input into water bodies. The required input parameters of EROSION 2D/3D (hydraulic roughness, infiltration rates etc.) were determined under field conditions by simulated rainfall experiments. These field experiments took place on selected non-vegetated plots of the Lusatian mining district in eastern Germany. Due to their huge influence on infiltration and erosion processes special characteristics of coal-containing dump soils (hydrophobicity, air trapping effect) have to be considered and implemented into the model within this survey.

  3. Natural and anthropogenic rates of soil erosion

    Science.gov (United States)

    Regions of land that are brought into crop production from native vegetation typically undergo a period of soil erosion instability, and long term erosion rates are greater than for natural lands as long as the land continues being used for crop production. Average rates of soil erosion under natur...

  4. Sodium bicarbonate solution as an anti-erosive agent against simulated endogenous erosion.

    Science.gov (United States)

    Messias, Danielle C F; Turssi, Cecilia P; Hara, Anderson T; Serra, Mônica C

    2010-08-01

    This study investigated whether sodium bicarbonate solution, applied on enamel previously exposed to a simulated intrinsic acid, can control dental erosion. Volunteers wore palatal devices containing enamel slabs, which were exposed twice daily extra-orally to hydrochloric acid (0.01 M, pH 2) for 2 min. Immediately afterwards, the palatal devices were re-inserted in the mouth and volunteers rinsed their oral cavity with a sodium bicarbonate solution or deionized water for 60 s. After the washout period, the palatal devices were refilled with a new set of specimens and participants were crossed over to receive the alternate rinse solution. The surface loss and surface microhardness (SMH) of specimens were assessed. The surface loss of eroded enamel rinsed with a sodium bicarbonate solution was significantly lower than the surface loss of eroded enamel rinsed with deionized water. There were no differences between treatments with sodium bicarbonate and deionized water for SMH measurements. Regardless of the solution used as an oral rinse, eroded enamel showed lower SMH than uneroded specimens. Rinsing with a sodium bicarbonate solution after simulated endogenous erosive challenge controlled enamel surface loss but did not alter the microhardness. (c) 2010 The Authors. Journal compilation (c) 2010 Eur J Oral Sci.

  5. Large-scale assessment of soil erosion in Africa: satellites help to jointly account for dynamic rainfall and vegetation cover

    Science.gov (United States)

    Vrieling, Anton; Hoedjes, Joost C. B.; van der Velde, Marijn

    2015-04-01

    Efforts to map and monitor soil erosion need to account for the erratic nature of the soil erosion process. Soil erosion by water occurs on sloped terrain when erosive rainfall and consequent surface runoff impact soils that are not well-protected by vegetation or other soil protective measures. Both rainfall erosivity and vegetation cover are highly variable through space and time. Due to data paucity and the relative ease of spatially overlaying geographical data layers into existing models like USLE (Universal Soil Loss Equation), many studies and mapping efforts merely use average annual values for erosivity and vegetation cover as input. We first show that rainfall erosivity can be estimated from satellite precipitation data. We obtained average annual erosivity estimates from 15 yr of 3-hourly TRMM Multi-satellite Precipitation Analysis (TMPA) data (1998-2012) using intensity-erosivity relationships. Our estimates showed a positive correlation (r = 0.84) with long-term annual erosivity values of 37 stations obtained from literature. Using these TMPA erosivity retrievals, we demonstrate the large interannual variability, with maximum annual erosivity often exceeding two to three times the mean value, especially in semi-arid areas. We then calculate erosivity at a 10-daily time-step and combine this with vegetation cover development for selected locations in Africa using NDVI - normalized difference vegetation index - time series from SPOT VEGETATION. Although we do not integrate the data at this point, the joint analysis of both variables stresses the need for joint accounting for erosivity and vegetation cover for large-scale erosion assessment and monitoring.

  6. X-DRAIN and XDS: a simplified road erosion prediction method

    Science.gov (United States)

    William J. Elliot; David E. Hall; S. R. Graves

    1998-01-01

    To develop a simple road sediment delivery tool, the WEPP program modeled sedimentation from forest roads for more than 50,000 combinations of distance between cross drains, road gradient, soil texture, distance from stream, steepness of the buffer between the road and the stream, and climate. The sediment yield prediction from each of these runs was stored in a data...

  7. Connecting America and Russia: Eocene erosion across the Arctic

    Science.gov (United States)

    Spiegel, Cornelia; Lisker, Frank; Piepjohn, Karsten; Estrada, Solveig; Lorenz, Henning

    2017-04-01

    The structural evolution of the Arctic Ocean and its surrounding continental areas is still poorly constrained, due to ice coverage and inaccessibility. The only scientific coring campaign within the central Arctic Ocean (the ACEX project) was positioned on the Lomonosov Ridge. This is a pronounced geomorphic structure of presumably continental origin, which stretches across the entire Arctic Ocean between the northernmost margin of the North American continent (Ellesmere Island) and the Siberian Shelf, bordering the New Siberian Islands. Geophysical data suggest that the Lomonosov Ridge may be continuous with the Siberian and Ellesmerian continental margins (e.g., Poselov et al., 2011). Rather unexpectedly, the ACEX project revealed that the Lomonosov Ridge was in very shallow water or even exposed to erosion between 44 and 18 Ma. As an explanation, it was suggested that the Lomonosov Ridge experienced compressional tectonics at that time, which may have affected the entire central Arctic Ocean, propagating from North America towards the Siberian shelf (ÓRegan et al., 2008). Here we present the first low-temperature thermochronological data from northern Ellesmere Island and from the New Siberian Islands, recording the erosion and exhumation history of these areas. Our apatite (U-Th)/He data show that while southern and central Ellesmere Island was characterized by very slow erosion during the Cenozoic, northern Ellesmere Island bordering the Arctic Ocean experienced km-scale erosion during the Eocene, contemporaneously with the stalled subsidence / uplift period of the Lomonosov Ridge. The thermochronology data from the New Siberian Islands reflect a complex erosion history: the eastern part of the North Siberian Islands, the DeLong Island Group, experienced rather limited erosion during the Cenozoic and most of the Mesozoic. By contrast, data from the western New Siberian Islands - the Lyakhov Island Group - in direct continuation of the Lomonosov Ridge are

  8. Mapping erosion prone areas in the Bouhamdane watershed (Algeria using the Revised Universal Soil Loss Equation through GIS

    Directory of Open Access Journals (Sweden)

    Bouguerra Hamza

    2017-03-01

    Full Text Available Soil erosion by water is a major problem that the Northern part of Algeria witnesses nowadays; it reduces: the productivity of agricultural areas due to the loss of lands, and leads to the loss of storage capacity in reservoirs, the deterioration of water quality etc. The aim of this study is to evaluate the soil losses due to water erosion, and to identify the sectors which are potentially sensitive to water erosion in the Bouhamdane watershed, that is located in the northeastern part of Algeria. To this end, the Revised Universal Soil Loss Equation (RUSLE was used. The application of this equation takes into account five parameters, namely the rainfall erosivity, topography, soil erodibility, vegetative cover and erosion control practices. The product of these parameters under GIS using the RUSLE mathematical equation has enabled evaluating an annual average erosion rate for the Bouhamdane watershed of 11.18 t·ha-1·y-1. Based on the estimates of soil loss in each grid cell, a soil erosion risk map with five risk classes was elaborated. The spatial distribution of risk classes was 16% very low, 41% low, 28% moderate, 12% high and 3% very high. Most areas showing high and very high erosion risk occurred in the lower Bouhamdane watershed around Hammam Debagh dam. These areas require adequate erosion control practices to be implemented on a priority basis in order to conserve soil resources and reduce siltation in the reservoir.

  9. Splash erosion. A bibliometric Review

    Science.gov (United States)

    Fernández Raga, M. B.

    2012-04-01

    Ellison (1944) developed the splash board as a system for measuring splash erosion that was both cheap and reliable. Bollinne (1975), Morgan (1978, 1981). Mutchler (1967) described another different type of splash detectors according to whether they were passive or could register data. In the study mentioned above these authors included bottles, funnels, glasses, photography, markers. After that several devices has been made up like the splash sampler (Leguedois et al., 2005), soil tray (Van Dijk et al., 2002), splash funnel (Terry, 1989) and several rain cups (Fernandez-Raga et al., 2010; Molina and Llinares, 1996; Torri et al., 1987). Splash erosion research has materialized in the form of a number of papers published in international journals. The database of bibliographic references employed has been one of the most prestigious ones: theWeb of Science (ISI). The search was carried out on January 27th 2012. Among the 3x10^8 scholarly documents included in the Science Citation Index Expanded (SCI-EXPANDED) 1899 to present , the searching engine located 439 containing the word "splash erosion*", where the asterisk acts as a wildcard for any letter or group of letters. Of these, 383 were classified as articles, 87 as proceeding papers, 5 as editorial material, 2 as notes and 1 as correction. These documents have been published in 163 different journals, although four are particularly recurrent: Earth surface processes and Landforms, Catena, Soil Science Society of America Journal and Hydrological processes, with 41, 35, 35 and 26 published documents respectively. A geographic analysis of these articles has been carried out in an attempt to determine in what parts of the world research projects were making use of splash erosion. The results are that anglo-saxon countries, as USA, England and Australia dominate, particularly USA, with 130 articles. China and Japan are large communities of researches too, and some Central European countries as Belgium, France Germany

  10. Soil Erosion Threatens Food Production

    Directory of Open Access Journals (Sweden)

    Michael Burgess

    2013-08-01

    Full Text Available Since humans worldwide obtain more than 99.7% of their food (calories from the land and less than 0.3% from the oceans and aquatic ecosystems, preserving cropland and maintaining soil fertility should be of the highest importance to human welfare. Soil erosion is one of the most serious threats facing world food production. Each year about 10 million ha of cropland are lost due to soil erosion, thus reducing the cropland available for world food production. The loss of cropland is a serious problem because the World Health Organization and the Food and Agricultural Organization report that two-thirds of the world population is malnourished. Overall, soil is being lost from agricultural areas 10 to 40 times faster than the rate of soil formation imperiling humanity’s food security.

  11. Sports drinks and dental erosion.

    Science.gov (United States)

    Noble, Warden H; Donovan, Terence E; Geissberger, Marc

    2011-04-01

    Sports drinks were originally developed to improve hydration and performance in athletes taking part in intense or endurance sporting events. These drinks contain relatively high amounts of carbohydrates (sugars), salt, and citric acid. These ingredients create the potential for dental ramifications and overall public health consequences such as obesity and diabetes. High intake of sports drinks during exercise, coupled with xerostomia from dehydration, may lead to the possibility of erosive damage to teeth.

  12. Dental erosion in French adolescents

    OpenAIRE

    Muller-Bolla, Mich?le; Courson, Fr?d?ric; Smail-Faugeron, Violaine; Bernardin, Thibault; Lupi-P?gurier, Laurence

    2015-01-01

    Background Since the 2000s, different epidemiological studies focusing on the prevalence or the aetiology of DE in adolescents recognised them as an at-risk population due to their eating behaviours. None was carried out in French adolescents. The primary objective of this study was to assess the prevalence of dental erosion (DE) using the total BEWE score among adolescents in the department of Alpes Maritimes, France. The secondary objectives were to observe changes in prevalence estimates d...

  13. Dynamic Assessment of Soil Erosion Risk Using Landsat TM and HJ Satellite Data in Danjiangkou Reservoir Area, China

    Directory of Open Access Journals (Sweden)

    Pengpeng Han

    2013-08-01

    Full Text Available Danjiangkou reservoir area is the main water source and the submerged area of the Middle Route South-to-North Water Transfer Project of China. Soil erosion is a factor that significantly influences the quality and transfer of water from the Danjiangkou reservoir. The objective of this study is to assess the water erosion (rill and sheet erosion risk and dynamic change trend of spatial distribution in erosion status and intensity between 2004 and 2010 in the Danjiangkou reservoir area using a multicriteria evaluation method.The multicriteria evaluation method synthesizes the vegetation fraction cover, slope gradient, and land use. Based on the rules and erosion risk assessment results of the study area in 2004 and 2010, the research obtained the conservation priority map. This study result shows an improvement in erosion status of the study area, the eroded area decreased from 32.1% in 2004 to 25.43% in 2010. The unchanged regions dominated the study area and that the total area of improvement grade erosion was larger than that of deterioration grade erosion. The severe, more severe, and extremely severe areas decreased by 4.71%, 2.28%, and 0.61% of the total study area, respectively. The percentages of regions where erosion grade transformed from extremely severe to slight, light and moderate were 0.18%, 0.02%, and 0.30%, respectively. However, a deteriorated region with a 2,897.60 km2 area was still observed. This area cannot be ignored in the determination of a general governance scheme. The top two conservation priority levels cover almost all regions with severe erosion and prominent increase in erosion risk, accounting for 7.31% of the study area. The study results can assist government agencies in decision making for determining erosion control areas, starting regulation projects, and making soil conservation measures.

  14. Effects of Nozzle Configuration on Rock Erosion Under a Supercritical Carbon Dioxide Jet at Various Pressures and Temperatures

    OpenAIRE

    Man Huang; Yong Kang; Xiaochuan Wang; Yi Hu; Deng Li; Can Cai; Feng Chen

    2017-01-01

    The supercritical carbon dioxide (SC-CO2) jet offers many advantages over water jets in the field of oil and gas exploration and development. To take better advantage of the SC-CO2 jet, effects of nozzle configuration on rock erosion characteristics were experimentally investigated with respect to the erosion volume. A convergent nozzle and two Laval nozzles, as well as artificial cores were employed in the experiments. It was found that the Laval nozzle can enhance rock erosion ability, whic...

  15. Ascribing soil erosion of hillslope components to river sediment yield.

    Science.gov (United States)

    Nosrati, Kazem

    2017-06-01

    In recent decades, soil erosion has increased in catchments of Iran. It is, therefore, necessary to understand soil erosion processes and sources in order to mitigate this problem. Geomorphic landforms play an important role in influencing water erosion. Therefore, ascribing hillslope components soil erosion to river sediment yield could be useful for soil and sediment management in order to decrease the off-site effects related to downstream sedimentation areas. The main objectives of this study were to apply radionuclide tracers and soil organic carbon to determine relative contributions of hillslope component sediment sources in two land use types (forest and crop field) by using a Bayesian-mixing model, as well as to estimate the uncertainty in sediment fingerprinting in a mountainous catchment of western Iran. In this analysis, 137 Cs, 40 K, 238 U, 226 Ra, 232 Th and soil organic carbon tracers were measured in 32 different sampling sites from four hillslope component sediment sources (summit, shoulder, backslope, and toeslope) in forested and crop fields along with six bed sediment samples at the downstream reach of the catchment. To quantify the sediment source proportions, the Bayesian mixing model was based on (1) primary sediment sources and (2) combined primary and secondary sediment sources. The results of both approaches indicated that erosion from crop field shoulder dominated the sources of river sediments. The estimated contribution of crop field shoulder for all river samples was 63.7% (32.4-79.8%) for primary sediment sources approach, and 67% (15.3%-81.7%) for the combined primary and secondary sources approach. The Bayesian mixing model, based on an optimum set of tracers, estimated that the highest contribution of soil erosion in crop field land use and shoulder-component landforms constituted the most important land-use factor. This technique could, therefore, be a useful tool for soil and sediment control management strategies. Copyright

  16. Impacts of shoreline erosion on coastal ecosystems in Songkhla Province

    Directory of Open Access Journals (Sweden)

    Nipaporn Chusrinuan

    2009-07-01

    Full Text Available Songkhla Province is located on the eastern coast of the southern Thai Peninsula, bordering the Gulf of Thailand for approximately 107 km. Most of the basin’s foreshores have been extensively developed for housing, tourism and shrimp farming. The beaches are under deteriorating impacts, often causing sediment transport which leads to an unnaturally high erosion rate. This natural phenomenon is considered to be a critical problem in the coastal areas affected by the hazard of coastal infrastructure and reduced beach esthetics for recreation. In this study, shoreline changes were compared between 1975 and 2006 using aerial photographs and Landsat imageries using Geographic Information System (GIS. The results revealed that 18.5 km2 of the coastal areas were altered during the period. Of this, 17.3 km2 suffered erosion and 1.2 km2were subjected to accretion. The most significant changes occurred between 1975-2006. Shoreline erosion was found at Ban Paktrae, Ranot District, with an average erosion rate of 5.3 m/year, while accretion occurred at Laem Samila, MuangSongkhla District with an average accretion rate of 2.04 m/year. The occurrences of shoreline erosion have contributed to the degradation of coastal soil and water quality, destruction of beach and mangrove forests, loss of human settlements and livelihood.These processes have led to deterioration of the quality of life of the residents. Prevention and mitigation measures to lessen economic and social impacts due to shoreline erosion are discussed.

  17. Experimental wind-driven rain erosion study on agricultural soils

    Science.gov (United States)

    Marzen, Miriam; Iserloh, Thomas; Brings, Christine; Fister, Wolfgang; Seeger, Manuel; Ries, Johannes B.

    2014-05-01

    Wind is potentially capable to considerably increase soil erosion by rain drops. In contrast to laboratory experiments, in-situ experiments enable the measurement of soil erosion by wind and rain including the reactions of relatively intact soil surfaces and a complete body of soil. The Portable Wind and Rainfall Simulator of Trier University was applied on winter cereal fields to measure rain erosion on agricultural areas with and without the influence of wind. The test areas are situated near Pamplona, Navarre and recognized to be representative for large parts of northern Spain concerning soil, land use and climate. The soil surfaces on the fields were ploughed and sparsely covered by recently sowed winter cereals. The soil water content was close to saturation due to long lasting rainfall. Runoff was medium to high with runoff-coefficients ranging from 26 to 100%. The eroded material from rainfall simulations ranged from 14.5 to 42.5 g m² / 30min. The eroded material from wind-driven rain ranged from 28.1 to 47.3 g m² / 30 min. Compared to windless rainfall, the wind-driven rain increased erosion of soil material up to 82.2%. In one case, the eroded material decreased by 18.3%. The results indicate a strong influence of wind on rain erosion on recently seeded agricultural soils. Wind influence can be an important aspect for the general assessment of sheet erosion and supports the finding that a neglect of this factor might lead to severe underestimation of soil loss.

  18. Modeling regional wind erosion using different model

    Science.gov (United States)

    Guo, Zhongling; Chang, Chunping; Wang, Rende; Li, Jifeng; Li, Qing

    2017-04-01

    Wind erosion is an important factor causing soil degradation in arid and semi-arid regions. The need to quantitatively evaluate wind induced soil erosion yields many wind erosion models. These models include Wind Erosion Equation (WEQ), Revised Wind Erosion Equation (RWEQ),Wind Erosion Predicted System (WEPS) etc. at a field scale and Wind Erosion Assessment Model (WEAM), Integrated Wind Erosion Modeling System (IWEMS), AUStralian Land Erodibility Model (AUSLEM) etc. at a regional scale. The challenge of precisely estimating wind erosion at a regional scale still remain to date. To assess regional wind erosion, WEQ, RWEQ and WEPS have been scaled up to regional versions. However, no attempt is performed to compare these models for regional wind erosion modeling. In this study, the regional versions of WEQ, RWEQ, WEPS and WEAM, IWEMS, AUSLEM will be selected to model regional wind erosion of farmlands in the Kangbao County of northern China with annual soil loss by wind erosion based on 137 Cs analysis. Remote sensing image is used to determine the size and shape of local farmlands. Weather data of 2000-2010, China Soil Survey and published soil data, crops rotations etc. are compiled to generate raster layers of inputs for selected models using ArcGIS 10.2. These models were rebuilt based on ArcGIS Model-builder Module. Spatial distribution of annual soil loss by wind erosion determined from different model will be tested using annual soil loss data by 137 Cs analysis. Performances of these models will be investigated, and restrictions of these models will be further ascertained.

  19. GEOSTATISTICAL BASED SUSCEPTIBILITY MAPPING OF SOIL EROSION AND OPTIMIZATION OF ITS CAUSATIVE FACTORS: A CONCEPTUAL FRAMEWORK

    Directory of Open Access Journals (Sweden)

    ABDULKADIR T. SHOLAGBERU

    2017-11-01

    Full Text Available Soil erosion hazard is the second biggest environmental challenges after population growth causing land degradation, desertification and water deterioration. Its impacts on watersheds include loss of soil nutrients, reduced reservoir capacity through siltation which may lead to flood risk, landslide, high water turbidity, etc. These problems become more pronounced in human altered mountainous areas through intensive agricultural activities, deforestation and increased urbanization among others. However, due to challenging nature of soil erosion management, there is great interest in assessing its spatial distribution and susceptibility levels. This study is thus intend to review the recent literatures and develop a novel framework for soil erosion susceptibility mapping using geostatistical based support vector machine (SVM, remote sensing and GIS techniques. The conceptual framework is to bridge the identified knowledge gaps in the area of causative factors’ (CFs selection. In this research, RUSLE model, field studies and the existing soil erosion maps for the study area will be integrated for the development of inventory map. Spatial data such as Landsat 8, digital soil and geological maps, digital elevation model and hydrological data shall be processed for the extraction of erosion CFs. GISbased SVM techniques will be adopted for the establishment of spatial relationships between soil erosion and its CFs, and subsequently for the development of erosion susceptibility maps. The results of this study include evaluation of predictive capability of GIS-based SVM in soil erosion mapping and identification of the most influential CFs for erosion susceptibility assessment. This study will serve as a guide to watershed planners and to alleviate soil erosion challenges and its related hazards.

  20. Comparison of erosion and erosion control works in Macedonia, Serbia and Bulgaria

    Directory of Open Access Journals (Sweden)

    Ivan Blinkov

    2013-12-01

    Natural conditions in the Balkan countries contribute to the appearance of various erosion forms and the intensity of the erosion processes. Over the history of these countries, people who settled this region used the available natural resources to fill their needs (tree cutting, incorrect plugging, overgrazing, which contributed to soil erosion. Organized erosion control works in the Balkans started in the beginning of the 20th century (1905 in Bulgaria. The highest intensity of erosion control works were carried out during the period 1945 – 1990. Various erosion control works were launched. Bulgaria had a large anti-erosion afforestation, almost 1 million ha. Bulgaria's ecological river restoration approach has been in use for almost 50 years. Serbia contributed significant erosion and torrent control works on hilly agricultural areas. Specific screen barrages and afforestation on extremely dry areas are characteristic in Macedonia. A common characteristic for all countries is a high decrease in erosion control works in the last 20 years.

  1. Changes in the hydrological status of the basin due to the application of erosion control works

    Directory of Open Access Journals (Sweden)

    Radonjić Jasmina

    2016-01-01

    Full Text Available Protection of land with vegetation is the primary factor in the fight against water erosion with necessary application of biotechnical, technical, administrative and planning measures. One of the first basins to be treated with works for the protection against erosion and torrent control is the Gradasnica River basin. The basic parameters to display the changes of the hydrological status of the land are the state of erosion, the change of erosion-coefficient, annual sediment yield, specific annual sediment discharge through the hydrographic network, the value of the runoff curve number and value of the maximal discharge. Works on protection from erosion and regulations of torrents have influenced the decrease in erosion coefficient values from strong erosion (Z=0.99 to the value of weak erosion (Z=0.40, as well as the reduction of the maximum discharge value from Qmax(1956=108,12m3/s to the value of Qmax(2014=87.2 m3/s.

  2. Estimating landscape susceptibility to soil erosion using a GIS-based approach in Northern Ethiopia

    Directory of Open Access Journals (Sweden)

    Lulseged Tamene

    2017-09-01

    Full Text Available Soil erosion is a very critical form of land degradation resulting in the loss of soil nutrients and downstream sedimentation of water storages in the highlands of Ethiopia. As it is technically and financially impossible to conserve all landscapes affected by erosion, identification of priority areas of intervention is necessary. Spatially distributed erosion models can help map landscape susceptibility to erosion and identify high erosion risk areas. Integration of erosion models with geographic information systems (GIS enables assessing evaluate the spatial variability of soil erosion and plan implementing conservation measures at landscape levels. In this study, the Revised Universal Soil Loss Equation adjusted for sediment delivery ratio was used in a GIS system to assess landscape sensitivity to erosion and identify hotspots. The approach was applied in three catchments with size being 10–20 km2 and results were compared against quantitative and semi-quantitative data. The model estimated mean soil loss rates of about 45 t ha−1 y−1 with an average variability of 30% between catchments. The estimated soil loss rate is above the tolerable limit of 10 t ha−1 y−1. The model predicted high soil loss rates at steep slopes and shoulder positions as well as along gullies. The results of the study demonstrate that knowledge of spatial patterns of high soil loss risk areas can help deploy site-specific conservation measures.

  3. Assessing the efficiency of Mediterranean ditch networks in preventing vineyards soil erosion within landscape

    Science.gov (United States)

    Levavasseur, Florent; Bailly, Jean-Stéphane; Lagacherie, Philippe

    2013-04-01

    Water erosion of cultivated soils is a threat to the sustainability of agriculture, especially in Mediterranean areas. For a long time, Mediterranean farmers have thus adopted some soil conservation practices. Actual ditch networks, which are generally associated with terraces, result from historical successive farmer settlements and are one of these soil conservation practices. By intercepting surface run-off, ditches decrease slope length and prevent soil erosion on downstream plots. However, since water erosion hazard and ditch network geometries are highly variable in vineyards landscape and since ditch building and maintaining are costly, the objective of this study was to identify and map the resulting efficiency of ditch networks in preventing soil erosion. For a given area, a ditch network efficiency is defined here as the balance between the network density, i.e. network cumulated length for a given area unit, and the erosion sensitivity over an area which measures the performance of the ditch network in limiting soil erosion. The erosion efficiency of ditch networks was thus identified using both i) computer generated ditch networks with various spatial configurations and ii) the stream power index as an erosion sensitivity indicator, computed from a DTM in which each ditch network was burned. The stream power index of the actual networks were compared with a set of generated networks whose density and topology were selected to maximize the performance in preventing soil erosion thanks to the use of a self-developed optimized stochastic network generator. For four 1 km² hillslopes, we showed that the performances of actual networks to prevent soil erosion was among the best that were obtained by simulated networks with even greater densities. Furthermore, we showed that the stream power index values that accounted for the actual ditch networks to prevent soil erosion hazard was both minimal and weakly variable in the whole study area (30 km²) at

  4. Erosion control and watershed management by Spacelab photography

    Science.gov (United States)

    Koelbl, O.; Depury, P.

    1985-04-01

    The interpretability of false color Spacelab photographs for erosion control and water shed management was assessed using photos taken over Nepal and the Mount Everest Massif. The thematic interpretation was done by a geologist working in this region. Scale limitations, image reproduction, and filtering of the photographs are discussed. Results show that much information can be extracted using relatively simple means. Color infrared photography must be used since panchromatic imagery does not show enough detail.

  5. Variability of Arctic coastal erosion along the western Yukon coast

    OpenAIRE

    Konopczak, A. M.; Manson, G. K.; Couture, N. J.; Lantuit, H.

    2014-01-01

    Arctic coastal erosion can have substantial impacts on coastal infrastructure, sometimes prompting the need for aggressive adaptation strategies. It can also induce the release of large quantities of organic carbon and nutrients directly into the nearshore with potential impacts on the ecosystem and/or transformation into greenhouse gases upon contact with sea water. The recent major changes in summer sea ice extent, as well as the warming of sea temperature could potentially lead to greater ...

  6. Vegetation Restoration, Soil Erosion and Sediment Yield on the Loess Plateau After "GFG" Project

    Science.gov (United States)

    Jiao, Juying

    2017-04-01

    Soil erosion is an increasing environmental problem globally, and the Chinese Loess Plateau suffers the most severe soil erosion in the world. To control soil and water losses and improve ecosystem of the Loess Plateau, significant efforts have been made since the 1950s, especially the implementation of "Grain for Green (GFG)" policy in 1999 on a large scale. After about 15 years of "GFG" implementation, vegetation restored evidently, and soil erosion and sediment yield reduced markedly on the Loess Plateau region. However, for the lager-scale afforestation on the Loess Plateau, the relationship between afforestation and soil water carrying capacity, the sustainability of afforestation and ecosystem should be considered. Although the comprehensive practices have achieved remarkable soil erosion control, soil erosion is still likely to be very severe during heavy rainstorms, especially in gully slope. Attention should be paid in strengthening the storage and drainage measures in the inter-gully to prevent gravitational erosion by reducing the slope runoff flowing down the gully. Proper and rational control measures and management methods in different sections must be investigated further and focused on preventing soil erosion at the sources rather than intercepting sediment with potential risk to the watershed.

  7. Experimental investigation on erosive wear behaviour of plasma spray coated stainless steel

    Science.gov (United States)

    Girisha, K. G.; Sreenivas Rao, K. V.; Anil, K. C.; Sanman, S.

    2017-04-01

    Slurry erosion is an implicit problem in many engineering industrial components such as ore carrying pipelines, slurry pumps and extruders. Even the water turbine blades are subjected to erosive wear when the water contains considerable amount of silt. In the present study, Al2O3-40%TiO2 powder particles of average particle size of 50 micrometer were deposited on EN56B martenistic stainless steel by atmospheric plasma spray technique. Ni/Cr was pre coated to work as bond coat for good adhesion between coating and the substrate material. A coating thickness of 200 micrometer was achieved. Coated and un-coated substrates were subjected to slurry erosion test as per ASTM G-119 standard. Slurry erosion test rig was used to evaluate the erosion properties at room temperature condition by varying the spindle speed. Scanning electron microphotographs were taken before and after the slurry erosion test. Microstructures reveal uniform distribution of coating materials. Eroded surface shows lip, groove, and crater formation and dense coating resulting in less porosity. Micro hardness test was evaluated and reported. EDX analysis confirms the presence of Al, Ti and O2 particles. It was observed that, Al2O3-40%TiO2 coated substrates exhibit superior erosion resistance as compared to un-coated substrates due to higher hardness and less coating porosity.

  8. The acidic and erosive potential of five sports drinks.

    Science.gov (United States)

    Rees, Jeremy; Loyn, Theresa; McAndrew, Robert

    2005-12-01

    Sports drinks are becoming increasingly popular as we are all being encouraged to adopt a healthier lifestyle with regular exercise. However, many of these products are based on acidic fruits and may contribute to erosion. The aim of this study was to screen a number of these products for their potential to cause enamel erosion in vitro. The erosive potential of a number of readily available sports drinks was assessed in the laboratory by measuring their pH, neutralisable acidity and their ability to erode enamel. These were compared to a positive control, orange juice and a negative control, water. The pH of the sports drinks ranged from 3.16-3.70 with their neutralisable acidity ranging from 9.74-13.44 mls of 0.1M NaOH. The amount of enamel removed following 1-hour immersion in the sports drinks ranged from 1.18-5.36 microns. In comparison, the orange juice control had a pH of 3.68, a neutralisable acidity of 19.68 mls of 0.1 M NaOH and removed 3.24 microns of enamel. Many of the sports drinks tested were found to be erosive. This information will be of use to clinicians when counselling patients with tooth surface loss who use fruit based sports drinks regularly.

  9. Varioliform erosions in the stomach and duodenum

    Energy Technology Data Exchange (ETDEWEB)

    Lotz, W.; Schulz, D.; Munkel, G.

    1984-04-01

    One thousand five hundred and eighty-three patients who were x-rayed for dyspepsia showed varioliform erosions in 15.3%. Men had an incidence of 9.8%, almost twice as common as in women (5.5%). Mucosal polyps, usually of the hyperplastic type, occurred in 2.4%. 15% of patients with gastric ulcers and 16% of patients with duodenal ulcers had varioliform erosions. On the other hand, amongst patients with erosions, 11% had gastric ulcers and 8.3% duodenal ulcers. The definitions of erosion which have been given in the literature are partly contradictory, and are discussed. Varioliform erosions, also known as complete erosions, may be acute or chronic. They are the third most common cause of bleeding from the upper gastrointestinal tract. With modern radiological methods of examining the stomach, they are no longer a rare finding. 5 figs.

  10. DENTAL EROSION IN PRIMARY DENTITION- A REVIEW

    Directory of Open Access Journals (Sweden)

    Rafi Shaik

    2017-06-01

    Full Text Available BACKGROUND The pattern of oral diseases has been influenced by ever changing human lifestyle. Tooth wear especially dental erosion has drawn increasing attention as risk factor for tooth damage or loss in recent years. It is a common condition in primary dentition compared to permanent dentition due to thinner and less mineralised enamel. However, it is more worrying, when this condition is being found in an alarming proportion among children. The presence of dental erosion in children is likely to be associated with a number of general health and dietary factors, but it is also aggravated by the relatively more rapid progression of erosion in the deciduous teeth. An understanding of the aetiologies and risk factors for erosion is important for early recognition of dental erosion to prevent serious irreversible damage to the dentition. This paper discusses the erosion in children with regard to its epidemiology, prevalence, clinical features, measurement and prevention.

  11. Literature review of models for estimating soil erosion and deposition from wind stresses on uranium-mill-tailings covers

    Energy Technology Data Exchange (ETDEWEB)

    Bander, T.J.

    1982-11-01

    Pacific Northwest Laboratory (PNL) is investigating the use of a rock armoring blanket (riprap) to mitigate wind and water erosion of an earthen radon-suppression cover applied to uranium-mill tailings. The mechanics of wind erosion, as well as of soil deposition, are discussed in this report. Several wind erosion models are reviewed to determine if they can be used to estimate the erosion of soil from a mill-tailings cover. One model, developed by W.S. Chepil, contains the most-important factors that describe variables that influence wind erosion. Particular features of other models are also discussed, as well as the application of Chepil's model to a particular tailings pile. For this particular tailings pile, the estimated erosion was almost one inch per year for an unprotected tailings soil surface. Wide variability in the deposition velocity and lack of adequate deposition models preclude reliable estimates of the rate at which airborne particles are deposited.

  12. Choosing the target of adaptive soil erosion management in Mediterranean. Long vs. Extreme erosion, internal vs. external catchment dynamics

    Science.gov (United States)

    Smetanova, Anna; Follain, Stéphane; David, Mélodie; Ciampalini, Rossano; Raclot, Damien; Crabit, Armand; Le Bissonnais, Yves

    2017-04-01

    L, Le Bissonnais Y, Keesstra S. submitted -b. Stakeholders' perception of the relevance of water and sediment connectivity in water and land management. Land Degradation & Development [5] Stroosnijder L. 2005. Measurement of erosion: Is it possible? CATENA 64: 162-173.

  13. Estimating soil erosion risk and evaluating erosion control measures for soil conservation planning at Koga watershed in the highlands of Ethiopia

    Science.gov (United States)

    Molla, Tegegne; Sisheber, Biniam

    2017-01-01

    Soil erosion is one of the major factors affecting sustainability of agricultural production in Ethiopia. The objective of this paper is to estimate soil erosion using the universal soil loss equation (RUSLE) model and to evaluate soil conservation practices in a data-scarce watershed region. For this purpose, soil data, rainfall, erosion control practices, satellite images and topographic maps were collected to determine the RUSLE factors. In addition, measurements of randomly selected soil and water conservation structures were done at three sub-watersheds (Asanat, Debreyakob and Rim). This study was conducted in Koga watershed at upper part of the Blue Nile basin which is affected by high soil erosion rates. The area is characterized by undulating topography caused by intensive agricultural practices with poor soil conservation practices. The soil loss rates were determined and conservation strategies have been evaluated under different slope classes and land uses. The results showed that the watershed is affected by high soil erosion rates (on average 42 t ha-1 yr-1), greater than the maximum tolerable soil loss (18 t ha-1 yr-1). The highest soil loss (456 t ha-1 yr-1) estimated from the upper watershed occurred on cultivated lands of steep slopes. As a result, soil erosion is mainly aggravated by land-use conflicts and topographic factors and the rugged topographic land forms of the area. The study also demonstrated that the contribution of existing soil conservation structures to erosion control is very small due to incorrect design and poor management. About 35 % out of the existing structures can reduce soil loss significantly since they were constructed correctly. Most of the existing structures were demolished due to the sediment overload, vulnerability to livestock damage and intense rainfall. Therefore, appropriate and standardized soil and water conservation measures for different erosion-prone land uses and land forms need to be implemented in Koga

  14. Erosive lichen planus: a therapeutic challenge.

    Science.gov (United States)

    Romero, Williams; Giesen, Laura; Navajas-Galimany, Lucas; Gonzalez, Sergio

    2016-01-01

    Erosive lichen planus is an uncommon variant of lichen planus. Chronic erosions of the soles, accompanied by intense and disabling pain, are some of its most characteristic manifestations. We present the case of a woman who developed oral and plantar erosive lichen planus associated with lichen planus pigmentosus and ungueal lichen planus that were diagnosed after several years. The patient failed to respond to multiple therapies requiring longstanding medication but remained refractory. Knowledge of the treatment options for erosive lichen planus is insufficient. Further research is required to clarify their effectiveness, ideally adopting an evidence-based methodology.

  15. Erosion products in disruption simulation experiments

    Energy Technology Data Exchange (ETDEWEB)

    Safronov, V.; Arkhipov, N.; Bakhtin, V.; Barsuk, V.; Kurkin, S.; Mironova, E.; Toporkov, D.; Vasenin, S.; Zhitlukhin, A. [Troitsk Inst. for Innovation and Fusion Research, Troisk, Moscow region (Russian Federation); Arkhipov, I. [Inst. of Physical Chemistry, Russian Academy of Science, Moscow (Russian Federation); Werle, H.; Wuerz, H. [Forschungszentrum Karlsruhe (Germany)

    1998-07-01

    Erosion of divertor materials under tokamak disruption event presents a serious problem of ITER technology. Erosion restricts the divertor lifetime and leads to production of redeposited layers of the material retaining large amount of tritium, which is a major safety issue for future fusion reactor. Since ITER disruptive heatloads are not achievable in existing tokamaks, material erosion is studied in special simulation experiments. Till now the simulation experiments have focused mainly on investigation of shielding effect and measurement of erosion rate. In the present work the properties of eroded and redeposited graphite are studied under condition typical for hard ITER disruption. (author)

  16. Modelling soil erosion in a head catchment of Jemma Basin on the Ethiopian highlands

    Science.gov (United States)

    Cama, Mariaelena; Schillaci, Calogero; Kropáček, Jan; Hochschild, Volker; Maerker, Michael

    2017-04-01

    Soil erosion represents one of the most important global issues with serious effects on agriculture and water quality especially in developing countries such as Ethiopia where rapid population growth and climatic changes affect wide mountainous areas. The catchment of Andit-Tid is a head catchment of Jemma Basin draining to the Blue Nile (Central Ethiopia). It is located in an extremely variable topographical environment and it is exposed to high degradation dynamics especially in the lower part of the catchment. The increasing agricultural activity and grazing, lead to an intense use of the steep slopes which altered the soil structure. As a consequence, water erosion processes accelerated leading to the evolution of sheet erosion, gullies and badlands. This study is aimed at a geomorphological assessment of soil erosion susceptibility. First, a geomorphological map is generated using high resolution digital elevation model (DEM) derived from high resolution stereoscopic satellite data, multispectral imagery from Rapid Eye satellite system . The map was then validated by a detailed field survey. The final maps contains three inventories of landforms: i) sheet, ii) gully erosion and iii) badlands. The water erosion susceptibility is calculated with a Maximum Entropy approach. In particular, three different models are built using the three inventories as dependent variables and a set of spatial attributes describing the lithology, terrain, vegetation and land cover from remote sensing data and DEMs as independent variables. The single susceptibility maps for sheet, gully erosion as well as badlands showed good to excellent predictive performances. Moreover, we reveal and discuss the importance of different sets of variables among the three models. In order to explore the mutual overlap of the three susceptibility maps we generated a combined map as color composite whereas each color represents one component of water erosion. The latter map yield a useful information

  17. Development of a new submersible test to characterise the erosion of soils and sediments

    OpenAIRE

    NDOYE, Ousseynou; Chevalier, Christophe; Reiffsteck, Philippe; MINATCHY, Carlos; FANELLI, Sonia; Pham Van Bang, Damien

    2016-01-01

    Understanding the mechanism and behavior of the scour process is a most challenging subject. One part of this challenge is the in situ measurement of soil and sediment sensitivity to erosion (in undisturbed and submersible conditions). To improve this understanding, a new test, the Wheel Erosion Test (WET), was developed. It consists of a wheel rotating upon a layer of sediments located in an aquarium filled in with water. The rotating speed of the wheel and the distance to the sediment bed a...

  18. Sediment Enrichment Ratio and Nutrient Leached by Runoff and Soil Erosion on Cacao Plantation

    OpenAIRE

    Oteng Haridjaja

    2012-01-01

    Soil consevation management system is an activity for diminishing sediment enrichment ratio and nutrient leachedsby water run off and soil erosion processes. The research was aimed to study sediment enrichment ratio and nutrientleached by run off and soil erosion on cacao plantations. Arachis pintoi with strips parallel contour and multiplestrip cropping of upland rice or soybean (Glycine max) were planted to improve soil physical characterictic oncacao plantation as a main plant. The exprime...

  19. Assessing soil erosion risk using RUSLE through a GIS open source desktop and web application.

    Science.gov (United States)

    Duarte, L; Teodoro, A C; Gonçalves, J A; Soares, D; Cunha, M

    2016-06-01

    Soil erosion is a serious environmental problem. An estimation of the expected soil loss by water-caused erosion can be calculated considering the Revised Universal Soil Loss Equation (RUSLE). Geographical Information Systems (GIS) provide different tools to create categorical maps of soil erosion risk which help to study the risk assessment of soil loss. The objective of this study was to develop a GIS open source application (in QGIS), using the RUSLE methodology for estimating erosion rate at the watershed scale (desktop application) and provide the same application via web access (web application). The applications developed allow one to generate all the maps necessary to evaluate the soil erosion risk. Several libraries and algorithms from SEXTANTE were used to develop these applications. These applications were tested in Montalegre municipality (Portugal). The maps involved in RUSLE method-soil erosivity factor, soil erodibility factor, topographic factor, cover management factor, and support practices-were created. The estimated mean value of the soil loss obtained was 220 ton km(-2) year(-1) ranged from 0.27 to 1283 ton km(-2) year(-1). The results indicated that most of the study area (80 %) is characterized by very low soil erosion level (soil erosion was higher than 962 ton km(-2) year(-1). It was also concluded that areas with high slope values and bare soil are related with high level of erosion and the higher the P and C values, the higher the soil erosion percentage. The RUSLE web and the desktop application are freely available.

  20. Integration of fluvial erosion factors for predicting landslides along meandering rivers

    Science.gov (United States)

    Chen, Yi-chin; Chang, Kang-tsung; Ho, Jui-yi

    2015-04-01

    River incision and lateral erosion are important geomorphologic processes in mountainous areas of Taiwan. During a typhoon or storm event, the increase of water discharge, flow velocity, and sediment discharge enhances the power of river erosion on channel bank. After the materials on toe of hillslope were removed by river erosion, landslides were triggered at outer meander bends. Although it has been long expected that river erosion can trigger landslide, studies quantifying the effects of river erosion on landslide and the application of river erosion index in landslide prediction are still overlooked. In this study, we investigated the effect of river erosion on landslide in a particular meanders landscape of the Jhoukou River, southern Taiwan. We developed a semi-automatic model to separate meandering lines into several reach segments based on the inflection points and to calculate river erosion indexes, e.g. sinuosity of meander, stream power, and stream order, for each reach segment. This model, then, built the spatial relationship between the reaches and its corresponding hillslopes, of which the toe was eroded by the reach. Based on the spatial relationship, we quantified the correlations between these indexes and landslides triggered by Typhoon Morakot in 2009 to examine the effects of river erosion on landslide. The correlated indexes were then used as landslide predictors in logistic regression model. Results of the study showed that there is no significant correlation between landslide density and meander sinuosity. This may be a result of wider channel dispersing the erosion at a meandering reach. On the other hand, landslide density at concave bank is significantly higher than that at convex bank in the downstream (stream order > 3), but that is almost the same in the upstream (stream order segments. River sediment in the upstream is an erosion agent vertically scouring the river bed, resulting in a symmetrical effect on both concave and convex bank

  1. Communicating and Visualizing Erosion-associated Risks to Infrastructure

    Science.gov (United States)

    Hewett, Caspar; Simpson, Carolyn; Wainwright, John

    2016-04-01

    Soil erosion is a major problem worldwide, affecting agriculture, the natural environment and urban areas through its impact on flood risk, water quality, loss of nutrient-rich upper soil layers, eutrophication of water bodies, sedimentation of waterways and sediment-related damage to roads, buildings and infrastructure such as water, gas and electricity supply networks. This study focuses on risks to infrastructure associated with erosion and the interventions needed to reduce those risks. Deciding on what interventions to make means understanding better which parts of the landscape are most susceptible to erosion and which measures are most effective in reducing it. Effective ways of communicating mitigation strategies to stakeholders such as farmers, land managers and policy-makers are then essential if interventions are to be implemented. Drawing on the Decision-Support Matrix (DSM) approach which combines a set of hydrological principles with Participatory Action Research (PAR), a decision-support tool for Communicating and Visualizing Erosion-Associated Risks to Infrastructure (CAVERTI) was developed. The participatory component was developed with the Wear Rivers Trust, focusing on a case-study area in the North East of England. The CAVERTI tool brings together process understanding gained from modelling with knowledge and experience of a variety of stakeholders to address directly the problem of sediment transport. Development of the tool was a collaborative venture, ensuring that the problems and solutions presented are easily recognised by practitioners and decision-makers. This recognition, and ease of access via a web-based interface, in turn help to ensure that the tools get used. The web-based tool developed helps to assess, manage and improve understanding of risk from a multi-stakeholder perspective and proposes solutions to problems. We argue that visualization and communication tools co-developed by researchers and stakeholders are the best means

  2. Water Purification

    Science.gov (United States)

    1994-01-01

    The Vision Catalyst Purifier employs the basic technology developed by NASA to purify water aboard the Apollo spacecraft. However, it also uses an "erosion" technique. The purifier kills bacteria, viruses, and algae by "catalytic corrosion." A cartridge contains a silver-impregnated alumina bed with a large surface area. The catalyst bed converts oxygen in a pool of water to its most oxidative state, killing over 99 percent of the bacteria within five seconds. The cartridge also releases into the pool low levels of ionic silver and copper through a controlled process of erosion. Because the water becomes electrochemically active, no electricity is required.

  3. Erosion controls transpressional wedge kinematics

    Science.gov (United States)

    Leever, K. A.; Oncken, O.

    2012-04-01

    High resolution digital image analysis of analogue tectonic models reveals that erosion strongly influences the kinematics of brittle transpressional wedges. In the basally-driven experimental setup with low-angle transpression (convergence angle of 20 degrees) and a homogeneous brittle rheology, a doubly vergent wedge develops above the linear basal velocity discontinuity. In the erosive case, the experiment is interrupted and the wedge topography fully removed at displacement increments of ~3/4 the model thickness. The experiments are observed by a stereo pair of high resolution CCD cameras and the incremental displacement field calculated by Digital Particle Image Velocimetry (DPIV). From this dataset, fault slip on individual fault segments - magnitude and angle on the horizontal plane relative to the fault trace - is extracted using the method of Leever et al. (2011). In the non-erosive case, after an initial stage of strain localization, the wedge experiences two transient stages of (1) oblique slip and (2) localized strain partitioning. In the second stage, the fault slip angle on the pro-shear(s) rotates by some 30 degrees from oblique to near-orthogonal. Kinematic steady state is attained in the third stage when a through-going central strike-slip zone develops above the basal velocity discontinuity. In this stage, strain is localized on two main faults (or fault zones) and fully partitioned between plate boundary-parallel displacement on the central strike-slip zone and near-orthogonal reverse faulting at the front (pro-side) of the wedge. The fault slip angle on newly formed pro-shears in this stage is stable at 60-65 degrees (see also Leever et al., 2011). In contrast, in the erosive case, slip remains more oblique on the pro-shears throughout the experiment and a separate central strike-slip zone does not form, i.e. strain partitioning does not fully develop. In addition, more faults are active simultaneously. Definition of stages is based on slip on

  4. Conventional and anti-erosion fluoride toothpastes: effect on enamel erosion and erosion-abrasion.

    Science.gov (United States)

    Ganss, C; Lussi, A; Grunau, O; Klimek, J; Schlueter, N

    2011-01-01

    New toothpastes with anti-erosion claims are marketed, but little is known about their effectiveness. This study investigates these products in comparison with various conventional NaF toothpastes and tin-containing products with respect to their erosion protection/abrasion prevention properties. In experiment 1, samples were demineralised (10 days, 6 × 2 min/day; citric acid, pH 2.4), exposed to toothpaste slurries (2 × 2 min/day) and intermittently stored in a mineral salt solution. In experiment 2, samples were additionally brushed for 15 s during the slurry immersion time. Study products were 8 conventional NaF toothpastes (1,400-1,490 ppm F), 4 formulations with anti-erosion claims (2 F toothpastes: NaF + KNO(3) and NaF + hydroxyapatite; and 2 F-free toothpastes: zinc-carbonate-hydroxyapatite, and chitosan) and 2 Sn-containing products (toothpaste: 3,436 ppm Sn, 1,450 ppm F as SnF(2)/NaF; gel: 970 ppm F, 3,030 ppm Sn as SnF(2)). A mouth rinse (500 ppm F as AmF/NaF, 800 ppm Sn as SnCl(2)) was the positive control. Tissue loss was quantified profilometrically. In experiment 1, most NaF toothpastes and 1 F-free formulation reduced tissue loss significantly (between 19 and 42%); the Sn-containing formulations were the most effective (toothpaste and gel 55 and 78% reduction, respectively). In experiment 2, only 4 NaF toothpastes revealed significant effects compared to the F-free control (reduction between 29 and 37%); the F-free special preparations and the Sn toothpaste had no significant effect. The Sn gel (reduction 75%) revealed the best result. Conventional NaF toothpastes reduced the erosive tissue loss, but had limited efficacy regarding the prevention of brushing abrasion. The special formulations were not superior, or were even less effective. Copyright © 2011 S. Karger AG, Basel.

  5. Uncertainties in assessing tillage erosion - How appropriate are our measuring techniques?

    Science.gov (United States)

    Fiener, P.; Wilken, F.; Aldana-Jague, E.; Deumlich, D.; Gómez, J. A.; Guzmán, G.; Hardy, R. A.; Quinton, J. N.; Sommer, M.; Van Oost, K.; Wexler, R.

    2018-03-01

    Tillage erosion on arable land is a very important process leading to a net downslope movement of soil and soil constitutes. Tillage erosion rates are commonly in the same order of magnitude as water erosion rates and can be even higher, especially under highly mechanized agricultural soil management. Despite its prevalence and magnitude, tillage erosion is still understudied compared to water erosion. The goal of this study was to bring together experts using different techniques to determine tillage erosion and use the different results to discuss and quantify uncertainties associated with tillage erosion measurements. The study was performed in northeastern Germany on a 10 m by 50 m plot with a mean slope of 8%. Tillage erosion was determined after two sequences of seven tillage operations. Two different micro-tracers (magnetic iron oxide mixed with soil and fluorescent sand) and one macro-tracer (passive radio-frequency identification transponders (RFIDs), size: 4 × 22 mm) were used to directly determine soil fluxes. Moreover, tillage induced changes in topography were measured for the entire plot with two different terrestrial laser scanners and an unmanned aerial system for structure from motion topography analysis. Based on these elevation differences, corresponding soil fluxes were calculated. The mean translocation distance of all techniques was 0.57 m per tillage pass, with a relatively wide range of mean soil translocation distances ranging from 0.39 to 0.72 m per pass. A benchmark technique could not be identified as all used techniques have individual error sources, which could not be quantified. However, the translocation distances of the macro-tracers used were consistently smaller than the translocation distances of the micro-tracers (mean difference = - 26 ± 12%), which questions the widely used assumption of non-selective soil transport via tillage operations. This study points out that tillage erosion measurements, carried out under almost

  6. Sustainable agriculture, soil management and erosion from prehistoric times to 2100

    Science.gov (United States)

    Vanwalleghem, Tom; Gómez, Jose Alfonso; Infante Amate, Juan; González Molina, Manuel; Fernández, David Soto; Guzmán, Gema; Vanderlinden, Karl; Laguna, Ana; Giráldez, Juan Vicente

    2015-04-01

    The rational use of soil requires the selection of management practices to take profit of the beneficial functions of plant growth, water and nutrient storage, and pollutants removal by filtering and decomposition without altering its properties. However, the first evidence of important and widespread erosion peaks can generally be found with the arrival of the first farmers all over the world. In areas with a long land-use history such as the Mediterranean, clear signs indicating the advanced degradation status of the landscape, such as heavily truncated soils, are visible throughout. Soil conservation practices are then aimed at reducing erosion to geological rates, in equilibrium with long-term soil formation rates, while maximizing agricultural production. The adoption of such practices in most areas of the world are as old as the earliest soil erosion episodes themselves. This work firstly reviews historical evidence linking soil management and soil erosion intensity, with examples from N Europe and the Mediterranean. In particular, work by the authors in olive orchards will be presented that shows how significant variations in soil erosion rates between could be linked to the historical soil management. The potential of historical documents for calibrating a soil erosion model is shown as the model, in this case RUSLE-based and combining tillage and water erosion, adequately represents the measured erosion rate dynamics. Secondly, results from present-day, long-term farm experiments in the EU are reviewed to evaluate the effect of different soil management practices on physical soil properties, such as bulk density, penetration resistance, aggregate stability, runoff coefficient or sediment yield. Finally, we reflect upon model and field data that indicate how future global climate change is expected to affect soil management and erosion and how the examples used above hold clues about sustainable historical management practices that can be used successfully

  7. The success of headwater rehabilitation towards gully erosion control

    Science.gov (United States)

    Frankl, Amaury; Poesen, Jean; Nyssen, Jan

    2017-04-01

    rehabilitation, check dam, cut-and fill cycle, soil and water conservation, erosion

  8. Graffiti for science - erosion painting reveals spatially variable erosivity of sediment-laden flows

    Science.gov (United States)

    Beer, Alexander R.; Kirchner, James W.; Turowski, Jens M.

    2016-12-01

    Spatially distributed detection of bedrock erosion is a long-standing challenge. Here we show how the spatial distribution of surface erosion can be visualized and analysed by observing the erosion of paint from natural bedrock surfaces. If the paint is evenly applied, it creates a surface with relatively uniform erodibility, such that spatial variability in the erosion of the paint reflects variations in the erosivity of the flow and its entrained sediment. In a proof-of-concept study, this approach provided direct visual verification that sediment impacts were focused on upstream-facing surfaces in a natural bedrock gorge. Further, erosion painting demonstrated strong cross-stream variations in bedrock erosion, even in the relatively narrow (5 m wide) gorge that we studied. The left side of the gorge experienced high sediment throughput with abundant lateral erosion on the painted wall up to 80 cm above the bed, but the right side of the gorge only showed a narrow erosion band 15-40 cm above the bed, likely due to deposited sediment shielding the lower part of the wall. This erosion pattern therefore reveals spatial stream bed aggradation that occurs during flood events in this channel. The erosion painting method provides a simple technique for mapping sediment impact intensities and qualitatively observing spatially distributed erosion in bedrock stream reaches. It can potentially find wide application in both laboratory and field studies.

  9. Graffiti for science – erosion painting reveals spatially variable erosivity of sediment-laden flows

    Directory of Open Access Journals (Sweden)

    A. R. Beer

    2016-12-01

    Full Text Available Spatially distributed detection of bedrock erosion is a long-standing challenge. Here we show how the spatial distribution of surface erosion can be visualized and analysed by observing the erosion of paint from natural bedrock surfaces. If the paint is evenly applied, it creates a surface with relatively uniform erodibility, such that spatial variability in the erosion of the paint reflects variations in the erosivity of the flow and its entrained sediment. In a proof-of-concept study, this approach provided direct visual verification that sediment impacts were focused on upstream-facing surfaces in a natural bedrock gorge. Further, erosion painting demonstrated strong cross-stream variations in bedrock erosion, even in the relatively narrow (5 m wide gorge that we studied. The left side of the gorge experienced high sediment throughput with abundant lateral erosion on the painted wall up to 80 cm above the bed, but the right side of the gorge only showed a narrow erosion band 15–40 cm above the bed, likely due to deposited sediment shielding the lower part of the wall. This erosion pattern therefore reveals spatial stream bed aggradation that occurs during flood events in this channel. The erosion painting method provides a simple technique for mapping sediment impact intensities and qualitatively observing spatially distributed erosion in bedrock stream reaches. It can potentially find wide application in both laboratory and field studies.

  10. A review of concentrated flow erosion processes on rangelands: Fundamental understanding and knowledge gaps

    Directory of Open Access Journals (Sweden)

    Sayjro K. Nouwakpo

    2016-06-01

    Full Text Available Concentrated flow erosion processes are distinguished from splash and sheetflow processes in their enhanced ability to mobilize and transport large amounts of soil, water and dissolved elements. On rangelands, soil, nutrients and water are scarce and only narrow margins of resource losses are tolerable before crossing the sustainability threshold. In these ecosystems, concentrated flow processes are perceived as indicators of degradation and often warrant the implementation of mitigation strategies. Nevertheless, this negative perception of concentrated flow processes may conflict with the need to improve understanding of the role of these transport vessels in redistributing water, soil and nutrients along the rangeland hillslope. Vegetation influences the development and erosion of concentrated flowpaths and has been the primary factor used to control and mitigate erosion on rangelands. At the ecohydrologic level, vegetation and concentrated flow pathways are engaged in a feedback relationship, the understanding of which might help improve rangeland management and restoration strategies. In this paper, we review published literature on experimental and conceptual research pertaining to concentrated flow processes on rangelands to: (1 present the fundamental science underpinning concentrated flow erosion modeling in these landscapes, (2 discuss the influence of vegetation on these erosion processes, (3 evaluate the contribution of concentrated flow erosion to overall sediment budget and (4 identify knowledge gaps.

  11. Water

    Science.gov (United States)

    ... www.girlshealth.gov/ Home Nutrition Nutrition basics Water Water Did you know that water makes up more ... to drink more water Other drinks How much water do you need? top Water is very important, ...

  12. Dental erosion in French adolescents.

    Science.gov (United States)

    Muller-Bolla, Michèle; Courson, Frédéric; Smail-Faugeron, Violaine; Bernardin, Thibault; Lupi-Pégurier, Laurence

    2015-11-19

    Since the 2000s, different epidemiological studies focusing on the prevalence or the aetiology of DE in adolescents recognised them as an at-risk population due to their eating behaviours. None was carried out in French adolescents. The primary objective of this study was to assess the prevalence of dental erosion (DE) using the total BEWE score among adolescents in the department of Alpes Maritimes, France. The secondary objectives were to observe changes in prevalence estimates depending on both the cutoffvalue of total BEWE score with different teeth/dental surfaces examined, and to identify the related risk factors. A cross-sectional study in a multistage random sample of 339 14-yr-old schoolchildren was carried out in 2014. The children completed a self-administered questionnaire concerning diet and oral habits. Caries was assessed with ICDAS-II (International Caries Detection and Assessment System-II) criteria and erosion with BEWE (Basic Erosive Wear Examination) index. The total BEWE score was calculated to assess the DE prevalence with two cutoff values (3 and 1). Data were analysed using descriptive statistics and logistic regression models. The 331 children were aged 14.4 ± 0.5 years. The DE prevalence was 39 % using a total BEWE score ≥ 3. With a cutoff total BEWE score of 1 (at least one affected tooth), the prevalence varied from 3.9 to 56.8 % depending on the teeth/surfaces that were used for the analysis. The DE prevalence, assessed with only first molars and maxillary incisors, was about 54 %. The risk factors for DE (total BEWE score ≥ 3) were daily consumption of acidic beverages (OR: 4.0; 95 % CI: 2.1-7.6) and acidic sweets (OR: 3.2; 95 % CI: 1.2-8.0), low socio economic category (OR: 2.4; 95 % CI: 1.1-5.0) and visible dental biofilm (OR: 2.0; 95 % CI: 1.2-3.4). Depending on the method chosen, the prevalence varied from 3.9 to 56.8 % among these adolescents. Thus, a consensus on choice of index, teeth to examine and age at

  13. Computational analysis of Pelton bucket tip erosion using digital image processing

    Science.gov (United States)

    Shrestha, Bim Prasad; Gautam, Bijaya; Bajracharya, Tri Ratna

    2008-03-01

    Erosion of hydro turbine components through sand laden river is one of the biggest problems in Himalayas. Even with sediment trapping systems, complete removal of fine sediment from water is impossible and uneconomical; hence most of the turbine components in Himalayan Rivers are exposed to sand laden water and subject to erode. Pelton bucket which are being wildly used in different hydropower generation plant undergoes erosion on the continuous presence of sand particles in water. The subsequent erosion causes increase in splitter thickness, which is supposed to be theoretically zero. This increase in splitter thickness gives rise to back hitting of water followed by decrease in turbine efficiency. This paper describes the process of measurement of sharp edges like bucket tip using digital image processing. Image of each bucket is captured and allowed to run for 72 hours; sand concentration in water hitting the bucket is closely controlled and monitored. Later, the image of the test bucket is taken in the same condition. The process is repeated for 10 times. In this paper digital image processing which encompasses processes that performs image enhancement in both spatial and frequency domain. In addition, the processes that extract attributes from images, up to and including the measurement of splitter's tip. Processing of image has been done in MATLAB 6.5 platform. The result shows that quantitative measurement of edge erosion of sharp edges could accurately be detected and the erosion profile could be generated using image processing technique.

  14. Impact of erosion and tillage on the productivity and quality of selected semiarid soils of Iran

    Science.gov (United States)

    Mehdizade, B.; Asadi, H.; Shabanpour, M.; Ghadiri, H.

    2013-09-01

    This greenhouse research was carried out to study the effects of water and tillage erosion on agricultural productivity and soil quality in soil samples from a semiarid region of Iran. A factorial experiment of complete randomized block design was used to compare the effects of soil erosion (eroded and non-eroded soils), slope position, water stress and fertilizer (N-P-K) on yield and yield components of wheat as soil productivity index. The results showed that erosion ie water and tillage erosion has a significant effect (p<0.01) in decreasing soil productivity due to its negative impact on soil organic matter, nutrients (N and K) and hydraulic conductivity. Complete N-P-K fertilization and water stress had significant effects on increasing and decreasing of wheat yield, respectively. The effect of water stress in particular was so high that it could eclipse the erosion impact on yield reduction. Wheat dry matter and grain mass on foot and mid slopes were significantly higher than that on upslope positions where total N and available K were the lowest and equivalent calcium carbonate the highest. Saturated hydraulic conductivity and total nitrogen were found to be the most important soil properties as far as their correlations to wheat yield are concerned.

  15. Rainfall erosivity in Brazil: A Review

    Science.gov (United States)

    In this paper, we review the erosivity studies conducted in Brazil to verify the quality and representativeness of the results generated and to provide a greater understanding of the rainfall erosivity (R-factor) in Brazil. We searched the ISI Web of Science, Scopus, SciELO, and Google Scholar datab...

  16. EVALUATION OF RAINFALL EROSIVIT OF RAINFALL EROSIVITY ...

    African Journals Online (AJOL)

    eobe

    climate change [19]. Vegetation intercepts rain, reducing its energy and preventing splash erosion. It also slows runoff, reduces sheet erosion, and anchors and reinforces the soil ... hydro geological significance in terms of groundwater yield and exploitation ..... Australia's Tropics”, Australian Journal of Soil. Research. Vol.

  17. Saliva Parameters and Erosive Wear in Adolescents

    NARCIS (Netherlands)

    Zwier, N.; Huysmans, M. C. D. N. J. M.; Jager, D. H. J.; Ruben, J.; Bronkhorst, E. M.; Truin, G. J.

    2013-01-01

    The aim of this study was to investigate the relationship between several parameters of saliva and erosive wear in adolescents. (Un-)stimulated saliva was collected from 88 adolescents with erosion and 49 controls (age 16 +/- 1 years). Flow rate, pH and buffer capacity were determined immediately.

  18. Interrill soil erosion processes on steep slopes

    Science.gov (United States)

    To date interrill erosion processes and regimes are not fully understood. The objectives are to 1) identify the erosion regimes and limiting processes between detachment and transport on steep slopes, 2) characterize the interactive effects between rainfall intensity and flow depth on sediment trans...

  19. Past, Present, Future Erosion at Locke Island

    Energy Technology Data Exchange (ETDEWEB)

    Bjornstad, Bruce N.

    2006-08-08

    This report describes and documents the erosion that has occurred along the northeast side of Locke Island over the last 10 to 20 years. The principal cause of this erosion is the massive Locke Island landslide complex opposite the Columbia River along the White Bluffs, which constricts the flow of the river and deflects the river's thalweg southward against the island.

  20. Hydrogeological And Geotechnical Investigations Of Gully Erosion ...

    African Journals Online (AJOL)

    For many years, gully erosion and landslides are posing a serious threat to human existence, agricultural land, infrastructure and socio-economic activities in Calabar and its environs. Consequently, hydrogeological and geotechnical studies of gully erosion sites were carried out in order to provide information on the ...

  1. EPro Non-contact erosion profiling

    DEFF Research Database (Denmark)

    Meinert, Palle

    EPro is a profiler controlled by software, which is constructed to measure the same surface or work piece multiple times and track changes due to erosion.......EPro is a profiler controlled by software, which is constructed to measure the same surface or work piece multiple times and track changes due to erosion....

  2. Evaluation of soil factors controlling gully erosion

    Science.gov (United States)

    Ollobarren, Paul; Giménez, Rafael; Ángel Campo, Miguel; Casalí, Javier

    2015-04-01

    Current models for prediction of (ephemeral) gully erosion rely mainly on topographic factors while soil conditions are almost neglected. However, soil erodibility is essential for analyzing and properly modeling gully erosion. But, despite the wealth of studies to characterize soil vulnerability to gully erosion, a universal approach is still lacking. Moreover, a useful and feasible soil characterization for gully erosion prediction at large scale should be based on simple, quick, repeatable and relatively inexpensive tests to perform. In this work an experimental approach to quantify soil contribution on gully erosion is proposed. From simple methodologies and techniques found in the literature for assessing physical-chemical properties of the soil, a large pool of variables -that presumably underpin gully erosion- were defined. These methodologies includes the use of vane shear apparatus, penetrometers and a mini-rain simulator as well as some current (modified) laboratory tests for assessing soil crustability and erodibility. Thirteen ephemeral gullies developed under different soil condition in agricultural fields of Navarre (Spain) were selected for experiments. Then, the aforementioned variables were calculated for each of the gullies through field and lab experiments. Furthermore, the most relevant variables were detected by means of multivariate analysis and their contribution to gully erosion was finally quantified by using multiple regression analysis. In addition, gully erosion rates of typical agricultural fields are given.

  3. Reduction of soil erosion on forest roads

    Science.gov (United States)

    Edward R. Burroughs; John G. King

    1989-01-01

    Presents the expected reduction in surface erosion from selected treatments applied to forest road traveledways, cutslopes, fillslopes, and ditches. Estimated erosion reduction is expressed as functions of ground cover, slope gradient, and soil properties whenever possible. A procedure is provided to select rock riprap size for protection of the road ditch.

  4. FORECAST THE SOIL EROSION THROUGH THE CARTOGRAMS

    Directory of Open Access Journals (Sweden)

    Mădălina - Cristina Marian

    2014-06-01

    Full Text Available Soil erosion in Arges County affects a high percentage of agricultural land. Most agricultural lands are located on slopes undergoing erosion, excess humidity temporarily or permanently, landslides. The importance lies in the need to know theme addressed erosion, the erosive potential of the land, the causes and factors that led to the onset of erosion and its deployment at a accelerated rate and now, because the based on this knowledge to determine the effective measures to prevent and combat this phenomenon of soil degradation. The importance of knowing this erosion is related both to protect land and diminishing rates of clogging existing accumulation lakes in the river basin. Erosion mapping was carried out in recent years with the use of means modern cadastral- topographical. So not provided with sufficient precision to determine the areas affected by erosion. This paper presents methods using modern maps using satellite images, topographical precision instrumentation, cartograms results can be easily integrated into a GIS system monitoring. The information is graphically and containing a database solid. Cartograms accuracy depends on the quality of engineerings survey carried out in the field.

  5. Rethinking erosion on Java: a reaction

    NARCIS (Netherlands)

    Graaff, de J.; Wiersum, K.F.

    1992-01-01

    In a recent article (Diemont et al., 1991) about erosion on Java, it has been postulated that low inputs, not surface erosion, is the main cause of low productivity of upland food crops on this island. In this article it is argued that this hypothesis is too simple. An analysis of empirical field

  6. Soil erosion vulnerability in the verde river basin, southern minas gerais

    Directory of Open Access Journals (Sweden)

    Vinícius Augusto de Oliveira

    2014-06-01

    Full Text Available Soil erosion is one of the most significant environmental degradation processes. Mapping and assessment of soil erosion vulnerability is an important tool for planning and management of the natural resources. The objective of the present study was to apply the Revised Universal Soil Loss Equation (RUSLE using GIS tools to the Verde River Basin (VRB, southern Minas Gerais, in order to assess soil erosion vulnerability. A annual rainfall erosivity map was derived from the geographical model adjusted for Southeastern Brazil, calculating an annual value for each pixel. The maps of soil erodibility (K, topographic factor (LS, and use and management of soils (C were developed from soils and their uses map and the digital elevation model (DEM developed for the basin. In a GIS environment, the layers of the factors were combined to create the soil erosion vulnerability map according to RUSLE. The results showed that, in general, the soils of the VRB present a very high vulnerability to water erosion, with 58.68% of soil losses classified as "High" and "Extremely High" classes. In the headwater region of VRB, the predominant classes were "Very High" and "Extremely High" where there is predominance of Cambisols associated with extensive pastures. Furthermore, the integration of RUSLE/GIS showed an efficient tool for spatial characterization of soil erosion vulnerability in this important basin of the Minas Gerais state.

  7. Weld overlay coatings for erosion control

    Energy Technology Data Exchange (ETDEWEB)

    Levin, B.; DuPont, J.N.; Marder, A.R.

    1993-03-03

    A literature review was made. In spite of similarities between abrasive wear and solid particle erosion, weld overlay hardfacing alloys that exhibit high abrasion resistance may not necessarily have good erosion resistance. The performance of weld overlay hardfacing alloys in erosive environments has not been studied in detail. It is believed that primary-solidified hard phases such as carbides and intermetallic compounds have a strong influence on erosion resistance of weld overlay hardfacing alloys. However, relationships between size, shape, and volume fraction of hard phases in a hardfacing alloys and erosion resistance were not established. Almost all hardfacing alloys can be separated into two major groups based upon chemical compositions of the primary solidified hard phases: (a) carbide hardening alloys (Co-base/carbide, WC-Co and some Fe base superalloys); and (b) intermetallic hardening alloys (Ni-base alloys, austenitic steels, iron-aluminides).

  8. Dietary assessment and counseling for dental erosion.

    Science.gov (United States)

    Marshall, Teresa A

    2018-02-01

    Dental erosion occurs after exposure to intrinsic or extrinsic acids. Exposure to intrinsic gastrointestinal acids is associated with anorexia nervosa, bulimia nervosa, rumination syndrome, or gastroesophageal reflux. Extrinsic dietary acids from foods or beverages also can cause erosion, particularly when exposure is prolonged by holding or swishing behaviors. Clinicians should screen patients exhibiting dental erosion for anorexia nervosa, bulimia nervosa, rumination syndrome, and gastroesophageal reflux disease. Clinicians should screen patients without a medical explanation for their erosion for exposure to acidic foods and beverages, particularly for habits that prolong exposure. Identification of intrinsic and extrinsic acid exposures and recommendations to minimize exposures are important to prevent erosion and maintain oral health. Copyright © 2018 American Dental Association. Published by Elsevier Inc. All rights reserved.

  9. Erosion Pressure on the Danish Coasts

    DEFF Research Database (Denmark)

    Sørensen, Carlo Sass; Sørensen, Per; Kroon, Aart

    Coastlines around the world are receding due to coastal erosion.With rising sea levels and a potential climatic deterioration due to climate change, erosion rates are likely to increase at many locations in the future.Together with the current preference of people to settle near or directly...... by the ocean, coastal erosion issues become increasingly more important to the human values at risk. Along many Danish coastlines, hard structures already act as coastal protection in the form of groins, breakwaters, revetments etc. These eroding coasts however still lack sand and where the public, in general......, neglects the need for sand replenishment i.e. in the form of repeated sand nourishments. Here we present a conceptual model and method for dividing coastal erosion into acute and chronic erosion pressure, respectively. We focus on the model use for management and climate change adaptation purposes...

  10. Rainfall erosivity index for the Ghana Atomic Energy Commission site

    National Research Council Canada - National Science Library

    Paul Essel; Eric T Glover; Serwaa Yeboah; Yaw Adjei-Kyereme; Israel Nutifafa Doyi Yawo; Mawutoli Nyarku; Godfred S Asumadu-Sakyi; Gustav Kudjoe Gbeddy; Yvette Agyiriba Agyiri; Evans Mawuli Ameho; Emmanuel Atule Aberikae

    2016-01-01

      Rainfall erosivity is the potential ability for rainfall to cause soil loss. 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...

  11. Rainfall erosivity index for the Ghana Atomic Energy Commission site

    National Research Council Canada - National Science Library

    Essel, Paul; Glover, Eric T; Yeboah, Serwaa; Adjei-Kyereme, Yaw; Yawo, Israel Nutifafa Doyi; Nyarku, Mawutoli; Asumadu-Sakyi, Godfred S; Gbeddy, Gustav Kudjoe; Agyiri, Yvette Agyiriba; Ameho, Evans Mawuli; Aberikae, Emmanuel Atule

    2016-01-01

    Rainfall erosivity is the potential ability for rainfall to cause soil loss. 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...

  12. Ice-Release and Erosion Resistant Materials for Wind Turbines

    Science.gov (United States)

    Zhang, Wei; Brinn, Cameron; Cook, Alex; Pascual-Marquez, Fernando

    2017-11-01

    Icing conditions may cause wind turbine generators to partially lose productivity or to be completely shut down to avoid structural damage. At present, commercially available technologies to mitigate this problem consist of expensive, energy hungry heating elements, which costs roughly 70,000 euro per medium size turbine. Conventional passive ice protection coating systems heavily rely on delicate surface structures and expensive materials to create water repellent superhydrophobic / low surface energy surfaces, which have been proven to be ineffective against ice accumulation. The lack of performance among conventional ice protection materials stems from a flaw in the approach to the problem: failure to recognize that water in its liquid form (WATER) and water in its solid form (ICE) are two different things. Something that works for WATER does not automatically work for ICE. Another reason is that many superhydrophobic materials are often reliant upon often fragile micro-structured surfaces to achieve their intended effects. This paper discusses a fundamentally different approach to the creation of a robust, low cost, durable, and multifunctional materials for ice release and erosion resistance. This National Science Foundation sponsored ice-release coating technology holds promise for protecting wind turbine blades and towers, thus potentially increasing reliability for power generation under icing conditions. Because of the vulnerability of wind turbine blades to ice buildup and erosion damages, wind farm facilities stand to reap considerable benefits.

  13. 93 Farmers' Perception and Reponses to Soil erosion in Zing Local ...

    African Journals Online (AJOL)

    `123456789jkl''''#

    Abstract. Soil erosion by water has remained a serious threat especially in the mountainous regions and sloppy lands where agriculture is practice, causing loss of valuable soil resources and attendant loss of agricultural productivity as well as siltation of the various water bodies across the continent of Africa and other ...

  14. Fragmentation and Erosion of Two-Dimensional Aggregates in Shear Flow

    NARCIS (Netherlands)

    Vassileva, Nikolina D.; van den Ende, Henricus T.M.; Mugele, Friedrich Gunther; Mellema, J.

    2007-01-01

    We consider single two-dimensional aggregates containing glass particles trapped at a water/oil or water/air interface. Two modes for aggregate break up are observed: break up by fragmentation into a few parts and break up by erosion of single particles. We have studied the critical shear rate for

  15. The price of soil erosion : an economic evaluation of soil conservation and watershed development

    NARCIS (Netherlands)

    Graaff, de J.

    1996-01-01

    Soil erosion by water is the principal cause of land degradation, and a major constraint to agricultural development in developing countries. In semi-arid zones measures have to be taken to reduce on-site soil, water and nutrient losses and in sub-humid mountainous zones the focus should also be on

  16. Short-term transport of glyphosate with erosion in Chinese loess soil - a flume experiment

    NARCIS (Netherlands)

    Yang, X.; Wang, Fei; Martins Bento, Celia; Xue, Sha; Gai, L.; Dam, van R.C.J.; Mol, J.G.J.; Ritsema, C.J.; Geissen, V.

    2015-01-01

    Repeated applications of glyphosate may contaminate the soil and water and threaten their quality both within the environmental system and beyond it through water erosion related processes and leaching. In this study, we focused on the transport of glyphosate and its metabolite aminomethylphosphonic

  17. Reduction of the efficacy of biochar as soil amendment by soil erosion

    DEFF Research Database (Denmark)

    Fister, Wolfgang; Heckrath, Goswin Johann; Greenwood, Philip

    , the preferential mobilization and redistribution of biochar in the landscape seems probable. Therefore, the question has been raised in recent years of how vulnerable biochar actually is to soil erosion. This is especially relevant on soils which are regularly cultivated and are vulnerable to soil erosion...... of biochar by wind erosion was due to very rainy wet soil surface conditions, tested with dried soil in the laboratory, in order to be able to at least reflect the worst case scenario. The results of the study show that for both experiments (wind and water ero-sion), the sediment from plots with biochar......Biochar is primarily used as soil amendment to improve soil quality and to sequester more carbon (C) to increase both medium- and long-term soil C stocks. These positive effects are obviously diminished if biochar is eroded and transported out of the field. Due to its low bulk density...

  18. Erosion Potential of Tooth Whitening Regimens as Evaluated with Polarized Light Microscopy.

    Science.gov (United States)

    Brambert, Patrick; Qian, Fang; Kwon, So Ran

    2015-11-01

    Tooth whitening is a widely utilized esthetic treatment in dentistry. With increased access to over-the-counter (OTC) systems concerns have been raised as to potential adverse effects associated with overuse of whitening materials. Therefore, this study aimed to evaluate enamel erosion due to different whitening regimens when used in excess of recommended guidelines. Extracted human teeth (n = 66) were randomly divided into 11 groups (n = 6/group). Specimens were exposed to OTC products: Crest Whitestrips and 5-minute natural white and a do-it-yourself (DIY) strawberry whitening recipe. Within each regimen, groups were further divided per exposure time: specimens receiving the recommended product dosage; 5 times the recommended dosage; and 10 times the recommended dosage. Negative and positive controls were treated with grade 3 water and 1.0% citric acid, respectively. Specimens were nail-varnished to limit application to a 1 × 4 mm window. Following treatment, specimens were sectioned and erosion (drop in μm) measured using polarized light microscopy. Two-sample t-test was used to detect difference in amount of enamel erosion between negative and positive groups, while one-way analysis of variance (ANOVA), followed by post hoc Dunnett's test was used to detect difference between set of treatment groups and negative control groups or among all experimental groups. There was significant difference in mean amount of enamel erosion (p erosion for positive control group was significantly greater than that for negative control group (23.50 vs 2.65 μm). There was significant effect for type of treatments on enamel erosion [F(9,50) = 25.19; p 0.05 for all instances), except for Natural White_10 times treatment group (p erosion. Enamel erosion due to the overuse of whitening products varies for different modalities and products. Therefore, caution is advised when using certain over-the-counter products beyond recommended guidelines, as there is potential for enamel

  19. Simulação da variabilidade espacial da erosão hídrica em uma sub-bacia hidrográfica de Latossolos no sul de Minas Gerais Simulation of water erosion spatial variability in a watershed representative of oxisols in southern Minas Gerais State

    Directory of Open Access Journals (Sweden)

    Antônio Marciano da Silva

    2008-10-01

    Full Text Available A simulação da distribuição espacial da erosão do solo consiste em uma ferramenta poderosa para o planejamento conservacionista em bacias hidrográficas, sendo uma importante aplicação da Equação Universal de Perdas de Solo (EUPS associada a princípios de interpolação espacial, principalmente a geoestatística. Este trabalho objetivou simular a distribuição espacial da erosão hídrica numa sub-bacia hidrográfica da região do Alto Rio Grande (MG, aplicando ferramentas geoestatísticas para distribuição espacial e mapeamento. Diferentes cenários de uso do solo foram analisados. A erosão foi estimada com base na EUPS aplicada a células, considerando as unidades pedológicas e diferentes usos em cada célula. O fator topográfico (LS das células foi obtido com base no Modelo Digital de Elevação da sub-bacia, identificando comprimento e direção principal do escoamento. A erosividade média anual da região é de 8.030 MJ mm ha-1 h-1 ano-1, e a erodibilidade dos solos foi extraída da literatura. A EUPS foi aplicada a cada célula, levando-se em conta a situação atual do solo, áreas degradadas plantadas com eucalipto, pastagem plantada e plantio convencional de milho, considerando a ocupação de toda a sub-bacia hidrográfica. Na situação atual, a sub-bacia apresenta taxas de erosão inferiores aos limites de tolerância para os respectivos solos, com exceção das áreas degradadas ocupadas por eucalipto e pastagem em Cambissolo. No entanto, em todas as situações analisadas, seu lado leste apresentou as maiores perdas de solo, especialmente para os cenários de eucalipto nas condições atuais e plantio convencional de milho em Cambissolo e Latossolo Vermelho-Amarelo, sendo necessária a aplicação de técnicas conservacionistas.Simulation of water erosion spatial distribution is an important tool for soil conservation planning in watersheds, being an important application of the Universal Soil Loss Equation (USLE

  20. Soft drinks and in vitro dental erosion.

    Science.gov (United States)

    Gravelle, Brent L; Hagen Ii, Ted W; Mayhew, Susan L; Crumpton, Brooks; Sanders, Tyler; Horne, Victoria

    2015-01-01

    The purpose of this investigation was to determine to what extent the in vitro exposure of healthy teeth to various commonly consumed carbonated soft drinks may precipitate dental erosion. Forty-two healthy, extracted, previously unerupted human molars were weighed prior to, during, and after suspension in various sugared and diet or zero-calorie carbonated beverages for 20 days; the specimens were stored at room temperature while being stirred at 275 rpm. The percentage decrease in tooth weight from before to after exposure represented the weight loss due to enamel erosion; values in the experimental groups varied from 3.22% to 44.52% after 20 days' exposure. Data were subjected to analysis of variance and post hoc Scheffe testing at a level of α = 0.05. Nonsugared drinks (diet and zero-calorie) as a whole were more erosive than sugared beverages. A significant positive correlation was found between the amount of titratable acid and percentage of tooth erosion, while a significant negative correlation was revealed between the beverage pH and percentage of tooth erosion. No significant correlations were found between calcium or phosphate ion concentrations and the amount of erosion. It appears that enamel erosion is dependent on not only the beverage flow rate, pH, and amount of titratable acid, but also whether the soft drink is of the diet or zero-calorie variety, which reflects the type of artificial sweetener present.

  1. Coupled wellbore erosion and stability analysis

    Science.gov (United States)

    Stavropoulou, M.; Papanastasiou, P.; Vardoulakis, I.

    1998-09-01

    This paper extends earlier work on sand erosion and presents an attempt to couple sand erosion to mechanical damage of rock around a wellbore. Porosity which evolves in time and space as surface erosion progresses, is chosen as the coupling parameter. Both rock elasticity and strength (cohesion) are assumed to depend on porosity in such a way that the material becomes weaker with increasing porosity. The mathematical model, consists of erosion equations, mixture flow equations and stress equilibrium equations, is solved numerically by Galerkin finite element method. Numerical results suggest that erosion, resulting in sand production, is high close to the free surface. Erosion is accompained by changes in porosity and a significant permeability increase. Erosion in the vicinity of the wellbore induces alterations in the mechanical behaviour of the medium. Weakening of rock stiffness leads to severe alteration of both effective stresses and pore pressure near the cavity. Since cohesion decreases with increasing porosity, one can also identify the time instant at which rock mechanical failure starts.

  2. Erosão hídrica em um Nitossolo Háplico submetido a diferentes sistemas de manejo sob chuva simulada. I - Perdas de solo e água Water erosion on an Hapludox submitted to different soil managements under simulated rainfall. I - Soil and water losses

    Directory of Open Access Journals (Sweden)

    D. Leite

    2004-12-01

    íduos culturais e com a cobertura pela copa das plantas. O índice D50 também se relacionou exponencialmente com a cobertura do solo pelos resíduos culturais.Soil management influences surface cover and roughness, and it is the major factor that affects water erosion. A rotating-boom rainfall simulator operated at a constant rainfall intensity of 64 mm h-1 and 0.2083 MJ ha-1 mm-1 kinetic energy was used to investigate water erosion and related parameters in six management systems of corn and bean crops. The experiments were carried out on a clayey loam structured soil (Hapludox with 0.165 m m-1 average slope, on the Southern Plateau of Santa Catarina State, Brazil, from March 2001 to April 2003. Three simulated rainfall tests were applied to the corn and three to the bean crop in the following treatments: plowing + disking (bare soil (SSC, corn and bean crop after plowing + disking on desiccated residue (PCO, corn and bean crop under no-tillage on desiccated residue on previously prepared soil (SDI, corn and bean crop under no-tillage on desiccated residue on never tilled soil (SDD, corn and bean crop under no-tillage on burned residue on never tilled soil (SDQ, and improved native pasture (CNM. Soil losses were strongly influenced by the soil management while water losses were only slightly affected. Results showed that the SDI treatment reduced the soil loss 96 % in relation to PCO, while the water loss, equivalent to 22 % of the applied rainfall volume in the PCO, was reduced to 7 % of the above-mentioned volume produced in the SDI in crop means. The burning of crop residues increased the soil loss 21 -fold compared to no burning while the water loss, equivalent to 22.5 % of the applied rainfall volume in the SDD, rose to 26.5 % of the above-mentioned volume obtained in the SDQ in the crop means. Soil losses were exponentially correlated with the soil cover percentage by crop residues and with the soil cover percentage by canopy crops. D50 index was also exponentially

  3. Validation of Erosion 3D in Lower Saxony - Comparison between modelled soil erosion events and results of a long term monitoring project

    Science.gov (United States)

    Bug, Jan; Mosimann, Thomas

    2013-04-01

    Since 2000 water erosion has been surveyed on 400 ha arable land in three different regions of Lower Saxony (Mosimann et al. 2009). The results of this long-term survey are used for the validation of the soil erosion models such as USLE and Erosion 3D. The validation of the physically-based model Erosion 3D (Schmidt & Werner 2000) is possible because the survey analyses the effects (soil loss, sediment yield, deposition on site) of single thunder storm events and also maps major factors of soil erosion (soil, crop, tillage). A 12.5 m Raster DEM was used to model the soil erosion events.Rainfalldata was acquired from climate stations. Soil and landuse parameters were derived from the "Parameterkatalog Sachsen"(Michael et al. 1996). During thirteen years of monitoring, high intensity storms fell less frequently than expected. High intensity rainfalls with a return period of five or ten years usually occurred during periods of maximum plant cover.Winter events were ruled out because dataon snow melt and rainfallwere not measured. The validation is therefore restricted to 80 events. The validation consists of three parts. The first part compares the spatial distribution of the mapped soil erosion with the model results. The second part calculates the difference in the amount of redistributed soil. The third part analyses off-site effects such as sediment yield and pollution of water bodies. The validation shows that the overall result of erosion 3D is quite good. Spatial hotspots of soil erosion and of off-site effects are predicted correctly in most cases. However, quantitative comparison is more problematic, because the mapping allows only the quantification of rillerosion and not of sheet erosion. So as a rule,the predicted soil loss is higher than the mapped. The prediction of rill development is also problematic. While the model is capable of predicting rills in thalwegs, the modelling of erosion in tractor tracks and headlands is more complicated. In order to

  4. Institutional landmarks in Brazilian research on soil erosion: a historical overview

    Directory of Open Access Journals (Sweden)

    Tiago Santos Telles

    2013-12-01

    Full Text Available The problem of soil erosion in Brazil has been a focus of agricultural scientific research since the 19th century. The aim of this study was to provide a historical overview of the institutional landmarks which gave rise to the first studies in soil erosion and established the foundations of agricultural research in Brazil. The 19th century and beginning of the 20th century saw the founding of a series of institutions in Brazil, such as Botanical Gardens, executive institutions, research institutes, experimental stations, educational institutions of agricultural sciences, as well as the creation and diversification of scientific journals. These entities, each in its own way, served to foster soil erosion research in Brazil. During the Imperial period (1808-1889, discussions focused on soil degradation and conserving the fertility of agricultural land. During the First Republic (1889-1930, with the founding of various educational institutions and consolidation of research on soil degradation conducted by the Agronomic Institute of Campinas in the State of São Paulo, studies focused on soil depletion, identification of the major factors causing soil erosion and the measures necessary to control it. During the New State period (1930-1945, many soil conservation practices were developed and disseminated to combat erosion and field trials were set up, mainly to measure soil and water losses induced by hydric erosion. During the Brazilian New Republic (1945-1964, experiments were conducted throughout Brazil, consolidating soil and water conservation as one of the main areas of Soil Science in Brazil. This was followed by scientific conferences on erosion and the institutionalization of post-graduate studies. During the Military Regime (1964-1985, many research and educational institutions were founded, experimental studies intensified, and coincidently, soil erosion reached alarming levels which led to the development of the no-tillage system.

  5. Redução da erosão hídrica em três sistemas de manejo do solo em um Cambissolo Húmico da região do Planalto Sul-Catarinense Reduction of water erosion in three soil management systems in an Inceptisol of the Planalto Sul-Catarinense region - Brazil

    Directory of Open Access Journals (Sweden)

    André Júlio do Amaral

    2008-10-01

    sido diferentes em cada ciclo cultural (1.545 MJ mm ha-1 h-1 no ciclo do trigo e 2.573 MJ mm ha-1 h-1 no ciclo da soja, refletindo-se nos resultados de perda de água e solo por erosão hídrica. O valor médio anual determinado do índice de erodibilidade do solo (fator K do modelo EUPS ou EUPSR de predição da erosão foi de 0,018 MJ-1 mm-1 ha-1. As perdas médias anuais de água e solo em geral foram relativamente pequenas em todas as situações estudadas, embora com a da primeira variável sendo maior no ciclo cultural do trigo e a da segunda, maior no ciclo cultural da soja, bem como com ambos os tipos de perda decrescendo na ordem de preparo convencional, preparo reduzido e semeadura direta e com a perda de solo proporcionalmente sendo bem mais reduzida pelo manejo do que a perda de água. Os valores médios provisoriamente determinados do fator C - cobertura e manejo do solo, do modelo EUPS ou EUPSR, para a sucessão cultural trigo-soja, nas condições climáticas da região do estudo, foram iguais a 0,23 no sistema de manejo com preparo convencional do solo, 0,06 no sistema de manejo com preparo reduzido e 0,023 no sistema de manejo semeadura direta.Tillage is one of the most important components of soil management in the process of crop production, normally used to create a favorable environment for sowing, seed germination and plant development. In addition, it is mainly determinant for the or surface soil physical conditions that will ultimately determine the erosion and the effectiveness of runoff reduction of the various soil management systems used to establish a given crop, in a given place. Considering these aspects, a field study under natural rainfall erosion was conducted in Lages, in the Southern upland region of the State of Santa Catarina, Brazil, between November, 2002, and October, 2005. The main objective of the study was to quantify soil and water losses caused by water-rainfall erosion through wheat (Triticum aestivum, L. and soybean

  6. Erosion risk assessment along coastlines, rivers, and lakes

    Science.gov (United States)

    Eidsvig, Unni; Harbitz, Carl B.; Issler, Dieter; Forsberg, Carl Fredrik; Høydal, Øyvind A.; Glimsdal, Sylfest; Frauenfelder, Regula

    2017-04-01

    An effect of the expected climate changes is that densely populated areas will be more exposed to natural hazards. There is a rising concern about geotechnical challenges associated with the transition zone between water and land, in particular with regard to erosion. This needs to be considered as part of the climate adaptation strategies in the society and applies to both coastal settlements and to settlements along rivers. Climate change, as reported by the IPCC, includes global warming, sea level rise as well as more precipitation, both with respect to intensity and frequency. A larger number of cities are expected to be affected by floods and with higher frequency. With large floods, the current speed in rivers and hence their erosion potential increases, leading to scouring along riverbanks, where important transport routes and other infrastructure are often located. The frequency and intensity of storm surges are expected to increase, as well as the risk of coastal erosion. In steep terrain, the likelihood of debris flows increases. The project "Multi-scale Erosion Risk under Climate Change" was initiated to prepare for such challenges as well as local climate adaptation. The project is an internal NGI strategic project funded by the Research Council of Norway for the period 2017 - 2019. The project aims to investigate relevant erosive and mass-flow processes in the coastal zone, along rivers, and in lakes. Further, the knowledge and tools to be developed within the project aim to reduce the risk associated with these processes, through appropriate land-use planning and innovative mitigation measures. The project is thematically subdivided into the following five work packages: WP1: Modelling of erosion processes in rivers, at the coast and in mass movements WP2: Floods, debris flows and sediment mobility in complex topography WP3: Coastal hydrodynamic processes WP4: Monitoring, warning and non-physical mitigation measures WP5: Dissemination and knowledge

  7. Meteorological conditions during extreme wind erosion events on heavy soils

    Directory of Open Access Journals (Sweden)

    Bronislava Mužíková

    2010-01-01

    Full Text Available Wind erosion in the Czech Republic conditions poses relatively a lot of danger, especially for the most fertile areas, where agricultural land is more vulnerable due to the large pieces of land and inappropriate crop rotation. This process causes damage to agriculture by loss of topsoil, fertilizers, seeds and crop damage as well as sedimentation in water recipients and on roads. It also has negative impacts on human health (airborne dust. Wind erosion is especially affected by climatic elements (wind, temperature, precipitation and evaporation etc. and soil characteristics (soil type, content of erodible particles, soil moisture. Wind erosion affects mainly light and medium heavy soil. South Moravia is an example of the territories to which this rule does not apply. Although soils in the Carpathian flysch subsoil are mainly heavy, erosion has been causing damage here for many decades. Quite strong dust storms are not rare, especially at the end of winter and in early spring when the soil is not covered by vegetation.Notable cases of dust storms in the area were recorded in local chronicles, and then written in the summary publication by dr. Švehlík. Interest of this publication was focused on the most destructive cases of dust storms in Bílé Karpaty foothills. The aim was to study meteorological conditions during the period before and during the occurrence of dust storms in the area in detail and to find the relationship between weather and the intensity of wind erosion. The data of wind speed and direction, temperature, precipitation and snow were evaluated. In all cases the average daily air temperature and ground air temperature was over the freezing point or closely under it. The temperature generally increased before the dust storm occurrence and it often happened from negative to positive temperature and the soil probably defrosted. Snow cover was very small or there was no snow cover at all. In the course of April wind erosion

  8. Simulation of chemical erosion in rough fractures.

    Science.gov (United States)

    Verberg, R; Ladd, A J C

    2002-05-01

    We report on numerical simulations of acid erosion in a fractured specimen of Carrara marble. The simulations combine two recent advances in lattice-Boltzmann methodology to accurately and efficiently calculate the velocity field in the pore space. A tracer diffusion algorithm was then used to calculate the distribution of reactants in the fracture, and the local erosion rate was obtained from the flux of tracer particles across the surfaces. Our results show that at large length scales, erosion leads to increased heterogeneity via channel formation, whereas at small length scales it tends to smooth out the roughness in the local aperture.

  9. Spatiotemporal variations in rainfall erosivity during the period of 1960-2011 in Guangdong Province, southern China

    Science.gov (United States)

    Zhao, Qinghe; Liu, Qian; Ma, Lijiao; Ding, Shengyan; Xu, Shanshan; Wu, Changsong; Liu, Pu

    2017-04-01

    Rainfall erosivity, which shows a potential risk of soil loss caused by water erosion, is an important factor in soil erosion process. In consideration of the critical condition of soil erosion induced by rainfall in Guangdong Province of southern China, this study analyzed the spatial and temporal variations in rainfall erosivity based on daily rainfall data observed at 25 meteorological stations during the period of 1960-2011. The methods of global spatial autocorrelation, kriging interpolation, Mann-Kendall test, and continuous wavelet transform were used. Results revealed that the annual rainfall erosivity in Guangdong Province, which spatially varied with the maximum level observed in June, was classified as high erosivity with two peaks that occur in spring and summer. In the direction of south-north, mean annual rainfall erosivity, which showed significant relationships with mean annual rainfall and latitude, gradually decreased with the high values mainly distributed in the coastal area and the low values mainly occurring in the lowlands of northwestern Guangdong. Meanwhile, a significant positive spatial autocorrelation which implied a clustered pattern was observed for annual rainfall erosivity. The spatial distribution of seasonal rainfall erosivity exhibited clustering tendencies, except spring erosivity with Moran's I and Z values of 0.1 and 1.04, respectively. The spatial distribution of monthly rainfall erosivity presented clustered patterns in January-March and July-October as well as random patterns in the remaining months. The temporal trend of mean rainfall erosivity in Guangdong Province showed no statistically significant trend at the annual, seasonal, and monthly scales. However, at each station, 1 out of 25 stations exhibited a statistically significant trend at the annual scale; 4 stations located around the Pearl River Delta presented significant trends in summer at the seasonal scale; significant trends were observed in March (increasing

  10. [Gastric band erosion: Alternative management].

    Science.gov (United States)

    Echaverry-Navarrete, Denis José; Maldonado-Vázquez, Angélica; Cortes-Romano, Pablo; Cabrera-Jardines, Ricardo; Mondragón-Pinzón, Erwin Eduardo; Castillo-González, Federico Armando

    2015-01-01

    Obesity is a public health problem, for which the prevalence has increased worldwide at an alarming rate, affecting 1.7 billion people in the world. To describe the technique employed in incomplete penetration of gastric band where endoscopic management and/or primary closure is not feasible. Laparoscopic removal of gastric band was performed in five patients with incomplete penetrance using Foley catheterization in the perforation site that could lead to the development of a gastro-cutaneous fistula. The cases presented include a leak that required surgical lavage with satisfactory outcome, and one patient developed stenosis 3 years after surgical management, which was resolved endoscopically. In all cases, the penetration site closed spontaneously. Gastric band erosion has been reported in 3.4% of cases. The reason for inserting a catheter is to create a controlled gastro-cutaneous fistula, allowing spontaneous closure. Various techniques have been described: the totally endoscopic, hybrid techniques (endoscopic/laparoscopic) and completely laparoscopic. A technique is described here that is useful and successful in cases where the above-described treatments are not viable. Copyright © 2015. Published by Masson Doyma México S.A.

  11. Soil Erosion Study on the Chinese Loess Plateau

    Science.gov (United States)

    Hu, Yaxian; Guo, Shengli; Kuhn, Nikolaus

    2017-04-01

    The Chinese Loess Plateau, because of its highly erodible loess soils and hilly topography, has been extensively studied by soil scientists and geomorphologists. As a research hotspot, there are five national-level field stations across the Loess Plateau, with hundreds of erosion plots set up with various sizes, lengths, slope angles and vegetation covers. In addition, huge indoor rain simulation facilities exist in in different institutes which can provide rainfall simulations under a wide range of controlled conditions. Consequently, national-level restoration projects have achieved tremendous improvements in curbing soil erosion and improving regional agro-ecosystem, mostly by afforestation and soil rehabilitation. However, when implementing the advanced techniques and models that have been widely applied in the rest of the world, there are often regional considerations, which demand new approaches to overcome. One example are the unintentional impacts of restoration efforts, such as the establishment of apple orchards. Over 20 years, they have caused an increase in soil erodibility and lowered local ground water levels. Neither before the introduction of this landscape rehabilitation technique, nor now, has the impact of intensive fruit production been systematically studied, despite lending itself to systematic experiments. The lack of research is attributed to the general idea that trees protect soils and improve environmental services. This presentation identifies several such specific regional environmental issues associated with soil erosion on the Loess Plateau and discusses strategies to avoid missing important research questions.

  12. Graffiti for science: Qualitative detection of erosional patterns through bedrock erosion painting

    Science.gov (United States)

    Beer, Alexander R.; Kirchner, James W.; Turowski, Jens M.

    2016-04-01

    Bedrock erosion is a crucial constraint on stream channel incision, and hence whole landscape evolution, in steep mountainous terrain and tectonically active regions. Several interacting processes lead to bedrock erosion in stream channels, with hydraulic shear detachment, plucking, and abrasion due to sediment impacts generally being the most efficient. Bedrock topography, together with the sediment tools and cover effects, regulate the rate and spatial pattern of in situ surface change. Measurements of natural bedrock erosion rates are valuable for understanding the underlying process physics, as well as for modelling landscape evolution and designing engineered structures. However, quantifying spatially distributed bedrock erosion rates in natural settings is challenging and few such measurements exist. We studied spatial bedrock erosion in a 30m-long bedrock gorge in the Gornera, a glacial meltwater stream above Zermatt. This stream is flushed episodically with sediment-laden streamflow due to hydropower operations upstream, with negligible discharge in the gorge in between these flushing events. We coated several bedrock surface patches with environmentally safe, and water-insoluble outdoor paint to document the spatial pattern of surface abrasion, or to be more precise, to document its driving forces. During four consecutive years, the change of the painted areas was recorded repeatedly with photographs before the painting was renewed. These photographs visually documented the spatial patterns of vertical erosion (channel incision), of lateral erosion (channel widening) and of downstream-directed erosion (channel clearance). The observed qualitative patterns were verified through comparison to quantitative change detection analyses based on annual high-resolution terrestrial laser scanning surveys of the bedrock surfaces. Comparison of repeated photographs indicated a temporal cover effect and a general height limit of the tools effect above the streambed

  13. Soil erosion and sediment control laws. A review of state laws and their natural resource data requirements

    Science.gov (United States)

    Klein, S. B.

    1980-01-01

    Twenty states, the District of Columbia, and the Virgin Islands enacted erosion and sediment control legislation during the past decade to provide for the implementation or the strengthening of statewide erosion and sediment control plans for rural and/or urban lands. That legislation and the state programs developed to implement these laws are quoted and reviewed. The natural resource data requirements of each program are also extracted. The legislation includes amendments to conservation district laws, water quality laws, and erosion and sediment control laws. Laws which provides for legislative review of administrative regulations and LANDSAT applications and/or information systems that were involved in implementing or gathering data for a specific soil erosion and sediment control program are summarized as well as principal concerns affecting erosion and sediment control laws.

  14. Puerto Rico Relative Erosion Potential (REP) - 1990

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The relative erosion potential is an indicator of sediment and pollution runoff from land based on slope, soil type, land cover (circa 1990) and (maximum monthly)...

  15. RAINFALL EROSIVITY IN SOUTHEASTERN NIGERIA *Ezemonye ...

    African Journals Online (AJOL)

    Osondu

    2011-10-13

    Oct 13, 2011 ... Ethiopian Journal of Environmental Studies and Management EJESM Vol. 5 No. 2 2012 ..... a rainfall erosivity model for the Mediterranean region, Journal of Hydrology ... Journal of Applied. Social Sciences, vol 1 no 1 pp 5-14.

  16. Puerto Rico Relative Erosion Potential (REP) - 2000

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The relative erosion potential is an indicator of sediment and pollution runoff from land based on slope, soil type, land cover (circa 2000) and (maximum monthly)...

  17. Sand transport, erosion and granular electrification

    DEFF Research Database (Denmark)

    Merrison, J.P.

    2012-01-01

    The transport of granular materials by wind has a major impact on our environment through sand/soil erosion and the generation and transport of atmospheric dust aerosols. Terrestrially the transport of dust involves billions of tons of material every year, influencing the global climate...... can affect grain transport through the generation of intense electric fields and processes of electrostatic assembly. Importantly the transport of sand is characterized by saltation, which is known to be an active process for erosion and therefore a source for dust and sand formation. Using novel...... erosion simulation techniques the link between grain transport rates and erosion rates has been quantified. Furthermore this can be linked to production rates for dust and has been associated with chemical and mineral alteration through a process of mechanical activation of fractured surfaces. This work...

  18. Vegetated Reinforced Soil Slope Streambank Erosion Control

    National Research Council Canada - National Science Library

    Sotir, Robbin B; Fischenich, J. C

    2003-01-01

    ...). The VRSS system is useful for the immediate repair or prevention of deeper failures providing a structurally sound system with soil reinforcement, drainage and erosion control typically on steepened...

  19. Regulated Environmental Activity Sites - CriticalErosion

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — Created based on the Critical Erosion Report for 2005. Indicates the condition of shoreline, determined by our staff of Coastal Engineers, for the year 2005. This...

  20. Rain Erosion/Measurement Impact Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The FARM Rain Erosion/Impact Measurement Lab develops solutions for deficiencies in the ability of materials, coatings and designs to withstand a severe operational...

  1. Puerto Rico Relative Vulnerability to Erosion

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical factors, such as the slope of the land, the texture of the soil, and the precipitation regime influence erosion in an area. Parts of Puerto Rico are very...

  2. Slurry Erosion Behavior of Destabilized and Deep Cryogenically Treated Cr-Mn-Cu White Cast Irons

    Directory of Open Access Journals (Sweden)

    S. Gupta

    2016-12-01

    Full Text Available The effects of destabilization treatment and destabilization followed by cryogenic treatment have been evaluated on the microstructural evolution and sand-water slurry erosion behavior of Cr-Mn-Cu white cast irons. The phase transformations after the destabilization and cryotreatment have been characterized by bulk hardness measurement, optical and scanning electron microscopy, x-ray diffraction analysis. The static corrosion rate has been measured in tap water (with pH=7 and the erosion-corrosion behavior has been studied by slurry pot tester using sand-water slurry. The test results indicate that the cryogenic treatment has a significant effect in minimizing the as-cast retained austenite content and transforming into martensitic and bainitic matrix embedded with ultra-fine M7C3 alloy carbides. In contrast, by conventional destabilization treatment retained austenite in the matrix are not fully eliminated. The slurry erosive wear resistance has been compared with reference to destabilized and cryotreated high chromium iron samples which are commonly employed for such applications. The cryotreated Cr-Mn-Cu irons have exhibited a comparable erosive wear performance to those of high chromium irons. Higher hardness combined with improved corrosion resistance result in better slurry erosion resistance.

  3. Effects of stubble and mulching on soil erosion by wind in semi-arid China

    Science.gov (United States)

    Cong, Peifei; Yin, Guanghua; Gu, Jian

    2016-07-01

    Soil erosion is a growing challenge for agricultural production in Northern China. To explore the effect of variation in stubble height and mulching biomass on soil erosion caused by wind, we conducted a field experiment using a quadratic rotation combination design. Results showed that the quantity of straw mulch was the dominant factor affecting soil erosion, and stubble height was of secondary importance. The soil water content in stubble and straw mulching treatments was higher than in a control treatment at 0-20 cm soil, and the tendency in the amount of soil water content was opposite to the amount of wind erosion (r = -0.882, n = 10, p soil water content observed in the stubble and mulch treatments at the 15-20 cm depth was higher than the change from 0-5 cm to 5-10 cm. Combined, the influence of a stubble height of 34 cm and mulch quantity of 4260 kg·ha-1 lowered the amount of erosion to 0.42 t·ha-1, and increased the corn yield to 11900 kg·ha-1. We determined that those were the most appropriate levels of stubble height and straw mulch for crop fields in the semi-arid regions of Northern China.

  4. DENTAL EROSION IN PRIMARY DENTITION- A REVIEW

    OpenAIRE

    Rafi Shaik

    2017-01-01

    BACKGROUND The pattern of oral diseases has been influenced by ever changing human lifestyle. Tooth wear especially dental erosion has drawn increasing attention as risk factor for tooth damage or loss in recent years. It is a common condition in primary dentition compared to permanent dentition due to thinner and less mineralised enamel. However, it is more worrying, when this condition is being found in an alarming proportion among children. The presence of dental erosion in c...

  5. Natural and anthropogenic rates of soil erosion

    Directory of Open Access Journals (Sweden)

    Mark A. Nearing

    2017-06-01

    Full Text Available Regions of land that are brought into crop production from native vegetation typically undergo a period of soil erosion instability, and long term erosion rates are greater than for natural lands as long as the land continues being used for crop production. Average rates of soil erosion under natural, non-cropped conditions have been documented to be less than 2 Mg ha−1 yr−1. On-site rates of erosion of lands under cultivation over large cropland areas, such as in the United States, have been documented to be on the order of 6 Mg ha−1 yr−1 or more. In northeastern China, lands that were brought into production during the last century are thought to have average rates of erosion over this large area of as much as 15 Mg ha−1 yr−1 or more. Broadly applied soil conservation practices, and in particular conservation tillage and no-till cropping, have been found to be effective in reducing rates of erosion, as was seen in the United States when the average rates of erosion on cropped lands decreased from on the order of 9 Mg ha−1 yr−1 to 6 or 7 Mg ha−1 yr−1 between 1982 and 2002, coincident with the widespread adoption of new conservation tillage and residue management practices. Taking cropped lands out of production and restoring them to perennial plant cover, as was done in areas of the United States under the Conservation Reserve Program, is thought to reduce average erosion rates to approximately 1 Mg ha−1 yr−1 or less on those lands.

  6. Impacts of decentralization - erosion or renewal?

    DEFF Research Database (Denmark)

    Ilsøe, Anna; Madsen, Jørgen Steen; Due, Jesper Jørgen

    2007-01-01

    to observe erosive tendencies in these hitherto sturdy fortresses of “organised decentralisation”. It is the main thesis of this article that the dualistic German system makes it more difficult for the German parties to adapt the bargaining system so that their overall coordination can be preserved even...... and the more homogeneous composition of company sizes in Denmark are core explanations why Denmark exhibits fewer erosive trends than Germany and more signs of renewal in the development towards multi-level regulation....

  7. SOIL EROSION FROM AREA IANOVA, TIMIS COUNTY

    Directory of Open Access Journals (Sweden)

    STELA URUIOC

    2009-01-01

    Full Text Available This study focuses on an area of erosion soils developed in Timis county of North - East of Timisoara. Soil erosion phenomenon intensity over the field of Ianova area is controlled by environment factors: relief, climate (rainfall intensity and runoff, vegetation, lithological substratum and human activity. Slope erosion state on erosion classes show that more than half of slope lands are affected by moderate and strong erosion. Ecopedological indicators of chemical soil characterization present lower values while erosion degree progresses. Thus, humus cantity progressively comes down from soil weak eroded (3,90-2,82% to soil excessive eroded (1,14%-1,11%. Nitrogen content expressed through nitrogen indicator has medium values (1,86-3,04 for weak and moderate eroded soils and small values (0,96-0,21 for excessive eroded soils. Potassium content substantially comes down from weak eroded soils (180ppm till to those excessive eroded (132 ppm. Phosphorus content has small values for all eroded soils (4,70-2,68 ppm. For eroded fields of Ianova area we propose: antierosional developments, agropedoimprovement works, antierosional agrotechnical works.

  8. Dental erosion: causes, diagnostics and treatment.

    Directory of Open Access Journals (Sweden)

    Cecilia Sosa-Puente

    2014-12-01

    Full Text Available Despite being a commonly studied topic, it is difficult to find studies which explain the problem of dental erosion. For this article, literature was analyzed to find information on the agents which trigger dental erosion, the main diagnosis methods, the most common treatments used nowadays and the interrelationship with dental materials. The etiology of dental erosion is multifactorial, including acids, eating disorders and gastro-esophageal reflux. However, biological factors such as saliva or habits also play a part in the establishment of this condition. In order to establish a reliable diagnosis, clinical appearance becomes decisive. The Basic Index Erosive Wear Examination (BEWE, created in 2008, is an auxiliary diagnosis tool for assessing the status and progress of the erosion. Treatment should be linked to the eradication of the causative agent and it can range from simple observational monitoring of slightly affected teeth to the placement of total crowns in the most severe cases, but this will depend entirely on the extent, severity, symptoms and type of dentition. Regarding dental materials used in the treatment of eroded parts, there are glass ionomer and composite; the latter presents the greatest resistance to biodegradation when interacting with acids. Glass ionomers are the most vulnerable material while resin is seen as the most resistant. In conclusion, dental erosion has become an issue of great importance in the dental practice because of its serious impact on dental structures. Consequently, it is ranked among the most important dental disorders in the present day.

  9. Participatory assessment of soil erosion severity and performance of mitigation measures using stakeholder workshops in Koga catchment, Ethiopia.

    Science.gov (United States)

    Jemberu, Walle; Baartman, Jantiene E M; Fleskens, Luuk; Ritsema, Coen J

    2018-02-01

    Farmers possess a wealth of knowledge regarding soil erosion and soil and water conservation (SWC), and there is a great demand to access it. However, there has been little effort to systematically document farmers' experiences and perceptions of SWC measures. Sustainable Land Management (SLM) has largely evolved through local traditional practices rather than adoption based on scientific evidence. This research aimed to assess soil erosion and performance of different SWC measures from the farmers' perspective by documenting their perceptions and experiences in Koga catchment, Ethiopia. To this aim, workshops were organised in three sub-catchments differing in slopes and SWC measures. Workshops included group discussions and field monitoring of erosion indicators and systematically describing the status of soil erosion, soil fertility and yield to assess the performance of SWC measures. Results show that farmers are aware of the harmful effects of ongoing soil erosion and of the impacts of mitigation measures on their farms. Sheet erosion was found to be the most widespread form of erosion while rill damage was critical on plots cultivated to cereals on steep slopes. The average rill erosion rates were 24.2 and 47.3 t/ha/y in treated and untreated farmlands, respectively. SWC reduced rill erosion on average by more than 48%. However, the impacts of SWC measures varied significantly between sub-watersheds, and farmers believed that SWC measures did not prevent erosion completely. Comparatively, graded stone-faced soil bunds revealed maximum desired impacts and were most appreciated by farmers, whereas level bunds caused water logging. Most traditional ditches were highly graded and begun incising and affected production of cereals. Despite the semi-quantitative nature of the methodology, using farmers' perceptions and experiences to document land degradation and the impacts of SWC measures is crucial as they are the daily users of the land and therefore directly

  10. Exploring Water Pollution. Part 3

    Science.gov (United States)

    Rillo, Thomas J.

    1976-01-01

    Lists over 30 outdoor science activities dealing with water formation, erosion, pollution, and other water-related topics. Provides, in addition, a selected bibliography of films, tapes, booklets and pamphlets, and filmstrips as additional reference materials. (CP)

  11. Rill erosion in natural and disturbed forests: 1. Measurements

    Science.gov (United States)

    P. R. Robichaud; J. W. Wagenbrenner; R. E. Brown

    2010-01-01

    Rill erosion can be a large portion of the total erosion in disturbed forests, but measurements of the runoff and erosion at the rill scale are uncommon. Simulated rill erosion experiments were conducted in two forested areas in the northwestern United States on slopes ranging from 18 to 79%. We compared runoff rates, runoff velocities, and sediment flux rates from...

  12. Satellite-based estimation of rainfall erosivity for Africa

    NARCIS (Netherlands)

    Vrieling, A.; Sterk, G.; Jong, S.M. de

    2010-01-01

    Rainfall erosivity is a measure for the erosive force of rainfall. Rainfall kinetic energy determines the erosivity and is in turn greatly dependent on rainfall intensity. Attempts for its large-scale mapping are rare. Most are based on interpolation of erosivity values derived from rain gauge

  13. Climate change impact on soil erosion in the Mandakini River Basin, North India

    Science.gov (United States)

    Khare, Deepak; Mondal, Arun; Kundu, Sananda; Mishra, Prabhash Kumar

    2017-09-01

    Correct estimation of soil loss at catchment level helps the land and water resources planners to identify priority areas for soil conservation measures. Soil erosion is one of the major hazards affected by the climate change, particularly the increasing intensity of rainfall resulted in increasing erosion, apart from other factors like landuse change. Changes in climate have an adverse effect with increasing rainfall. It has caused increasing concern for modeling the future rainfall and projecting future soil erosion. In the present study, future rainfall has been generated with the downscaling of GCM (Global Circulation Model) data of Mandakini river basin, a hilly catchment in the state of Uttarakhand, India, to obtain future impact on soil erosion within the basin. The USLE is an erosion prediction model designed to predict the long-term average annual soil loss from specific field slopes in specified landuse and management systems (i.e., crops, rangeland, and recreational areas) using remote sensing and GIS technologies. Future soil erosion has shown increasing trend due to increasing rainfall which has been generated from the statistical-based downscaling method.

  14. An application of LIDAR to analyses of El Nino erosion in the Netarts littoral cell, Oregon

    Science.gov (United States)

    Revell, D.L.; Komar, P.D.; Sallenger, A.H.

    2002-01-01

    El Nin??o produces coastal and beach erosion along the West Coast of the USA by elevating mean water levels so that tides are significantly higher than predicted, and by altering the paths of storms that generate large waves. In the past it has been difficult to adequately document the erosion impacts since they are so widespread. This difficulty has been solved through the application of LIDAR, which uses a scanning laser mounted in a small aircraft to rapidly and accurately survey beach elevations. This study uses LIDAR to document the beach changes and shoreline erosion that occurred during the 1997-98 El Nin??o within the Netarts Littoral Cell on the Oregon coast, a 14-km long "pocket beach" between large rocky headlands. The LIDAR surveys demonstrate that sand generally migrated northward within the cell due to the southwest approach of the El Nin??o storm waves, but there was a complex pattern of beach-elevation change due to the superposition of eroded rip-current embayments. The greatest beach erosion occurred near the south end of the cell, where it impacted Cape Lookout State Park, and to the north of the inlet to Netarts Bay where it threatened The Capes, a development of condominiums located on a high bluff. In both cases the LIDAR data proved to be extremely useful in quantifying the erosion, and in providing a better understanding of the erosion processes that occur during an El Nin??o.

  15. A method to assess soil erosion from smallholder farmers' fields: a case study from Malawi.

    Science.gov (United States)

    Mohamoud, Yusuf M

    2013-09-01

    Soil erosion by water is a major threat to sustainable food production systems in Africa. This study presents a qualitative soil erosion assessment method that links the number of broken ridges (NBRS) observed on a smallholder farmer's field after a rain event to factors of soil erosion (e.g., rainfall intensity, slope steepness, crop canopy height, and conservation practice) and to soil loss data measured from a runoff plot and receiving small streams. The assessment method consists of a rapid survey of smallholder farmers combined with field monitoring. Results show an indirect relationship between NBRS and factors of soil erosion. Results also show a direct relationship between NBRS and suspended sediment concentrations measured from an experimental runoff plot and receiving streams that drain the sub-watersheds where farmers' fields are located. Given the limited human and financial resources available to soil erosion research in developing countries, monitoring NBRS is a simple, cost-effective, and reliable erosion assessment method for regions where smallholder farmers practice contour ridging.

  16. Indicadores de contaminación biológica asociados a la erosión hídrica en una cuenca de Pampa Ondulada Argentina Indicators of biological contamination associated with water erosion in basin belonging the rolling pampa, Argentina

    Directory of Open Access Journals (Sweden)

    Celio I. Chagas

    2006-07-01

    í a nivel de la cuenca bajo estudio.Agriculture activities use 70% of the world water resources, partly for animal production and particularly cattle feeding. There is an outstanding risk of biological contamination associated with this kind of production because animal feces and urine containing pathogens can be transported to surface waterways through runoff. The present investigation was carried out in the Tala basin belonging to the Rolling Pampa region in which intense runoff and erosion processes are widespread. In this basin there are extensive cattle feeding farms which are located close to the natural waterways, in bottomlands with hydrohalomorphic soils. There is also an increasing surface devoted to feedlots and intensive swine and poultry productions. The main use of the surface waters from the river and tributaries is direct cattle drinking. The aim of the present work was to analyze through biological indicators, the potential contamination of runoff water and sediments accumulated in lowlands devoted to cattle production and to determinate their human or animal origin. The waters showed concentration of biological indicators belonging to faecal streptococci and enterococci which can be related to animal but no to human contamination processes. A close relationship was observed between total coliforms and erosion borne sediment concentration in the studied area. Thus, the capacity of these sediments for carrying bacteria potentially harmful for animal health like Salmonella spp. was confirmed. The runoff, erosion and biological contamination processes proved to be related in the studied basin.

  17. Erosion of galilean satellite surfaces by jovian magnetosphere particles.

    Science.gov (United States)

    Johnson, R E; Lanzerotti, L J; Brown, W L; Armstrong, T P

    1981-05-29

    The Galilean satellites of Jupiter-Io (J1), Europa (J2), Ganymede (J3), and Callisto (J4)-are embedded in the intense ion and electron fluxes of the Jovian magnetosphere. The effect of these particles on the icy surfaces of the outer three satellites depends on the fluxes and the efficiency of the sputtering of water ice by such particles. Recent laboratory measurements provided data on the erosion of water ice by energetic particles and showed that it occurs much faster than would be expected from normal sputtering theory. The Voyager spacecraft encounters with Jupiter provided the first measurements of ion fluxes (energies greater, similar 30 kiloelectron volts) in the vicinity of the Galilean satellites. Using the laboratory sputtering data together with particle measurements from the Voyager 1 low-energy charged particle experiment, the effects of erosion on the surfaces of J2 to J4 are estimated. It is shown that the surface of Europa could be eroded by as much as 100 meters over an eon (10(9) years). Column densities of water vapor that could be produced around the three satellites from particle bombardment of their surfaces are also calculated, and the sources and losses of oxygen in the gravitationally bound gas produced by sputtering or sublimation are estimated.

  18. Erosão hídrica em latossolo vermelho sob diversos sistemas de manejo do cafeeiro no Sul de Minas Gerais Water erosion in red latosol under diverse coffee plant management systems at South of Minas Gerais State, Brazil

    Directory of Open Access Journals (Sweden)

    Ricardo Carvalho

    2007-12-01

    Full Text Available A erosão hídrica contribui para a redução da sustentabilidade dos sistemas agrícolas. O presente estudo avaliou, sob condições de chuva natural, as perdas de solo, água, nutrientes e matéria orgânica em um Latossolo Vermelho distroférrico típico, com 12 % de declividade, localizado na região de Lavras (MG. O trabalho foi conduzido em parcelas experimentais de perdas de solo. Os sistemas de manejo estudados foram: café sob cultivo convencional, com capina manual (CCC; cultivo convencional, com roçado (CCR; cultivo convencional, com utilização de herbicida (CCH; cultivo orgânico, com capina manual (COC; cultivo orgânico, com roçado (COR; e como referência parcela com solo descoberto (SD. Nos sistemas de manejo em que foi mantida a cobertura da vegetação espontânea (roçado, obteve-se maior eficiência de proteção do solo quando comparado aos sistemas onde houve exposição do solo (capina. No sistema com utilização de herbicida, observou-se um comportamento intermediário. Todos os sistemas de manejo estudados se mostraram conservacionistas quanto à proteção do solo em relação à erosão hídrica, onde o espaçamento adensado merece ser enfatizado.Water erosion reduces the sustainability of agricultural systems. The present study evaluated under natural rainfall, the soil, water, nutrients and organic carbon losses in a typic dystroferric Red Latosol, with 12 % slope, located at Lavras region, Minas Gerais state, Brazil. The work was conducted in soil losses experimental plots. The studied treatments were: coffee under conventional cultivation with manual weeding (CCC; conventional cultivation with cleared undergrowth (CCR; conventional cultivation with herbicide use (CCH; organic cultivation with manual weeding (COC; organic cultivation with cleared undergrowth (COR; and test plot with bare soil (SD. In the systems where the expontaneous vegetation covers were maintained (cleared undergrowth there was more

  19. Mapping soil erosion susceptibility using GIS techniques within the Danube floodplain, the Calafat - Turnu Măgurele sector (Romania

    Directory of Open Access Journals (Sweden)

    Ionuş Oana

    2013-01-01

    Full Text Available The Danube floodplain, the Calafat - Turnu Măgurele sector, through its main features (topographic and climatic characteristics, land use and soil type and human activities, constitutes an area exposed to soil erosion. The main objective of the present research is to map soil erosion susceptibility using the GIS techniques for the computation and representation of areas, which are exposed to soil erosion correlated with the field data for the validation. Analyzing the entire model, the relatively simple methodology, the database consistence, the comparability of the results with the existent soil erosion values at national and local scale, we can say that the model was applied with success in the studied area (areas and classes of water erosion susceptibility: very low, low, moderate, high - Ciupercenii Noi, Desa, Măceşu de Jos, Grojdibodu, Orlea, very high - Rast, Negoi, Catane, Bistreţ, Goicea; areas and classes of wind erosion susceptibility: very low, low, moderate - Ciupercenii Noi, Dăbuleni, Ianca, high - Calafat, Poiana Mare, Desa, Goicea, Piscu Vechi, very high - Poiana Mare, Rast, Negoi, Bistreţ, Gighera, Orlea. The soil erosion susceptibility map can be useful for planning erosion control measures and for selecting suitable sites for runoff plot experiments.

  20. Modeling of soil erosion and sediment transport in the East River Basin in southern China

    Science.gov (United States)

    Wu, Yping; Chen, Ji

    2012-01-01

    Soil erosion is a major global environmental problem that has caused many issues involving land degradation, sedimentation of waterways, ecological degradation, and nonpoint source pollution. Therefore, it is significant to understand the processes of soil erosion and sediment transport along rivers, and this can help identify the erosion prone areas and find potential measures to alleviate the environmental effects. In this study, we investigated soil erosion and identified the most seriously eroded areas in the East River Basin in southern China using a physically-based model, Soil and Water Assessment Tool (SWAT). We also introduced a classical sediment transport method (Zhang) into SWAT and compared it with the built-in Bagnold method in simulating sediment transport process along the river. The derived spatial soil erosion map and land use based erosion levels can explicitly illustrate the identification and prioritization of the critical soil erosion areas in this basin. Our results also indicate that erosion is quite sensitive to soil properties and slope. Comparison of Bagnold and Zhang methods shows that the latter can give an overall better performance especially in tracking the peak and low sediment concentrations along the river. We also found that the East River is mainly characterized by sediment deposition in most of the segments and at most times of a year. Overall, the results presented in this paper can provide decision support for watershed managers about where the best management practices (conservation measures) can be implemented effectively and at low cost. The methods we used in this study can also be of interest in sediment modeling for other basins worldwide.

  1. Soil losses from typic cambisols and red latosol as related to three erosive rainfall patterns

    Directory of Open Access Journals (Sweden)

    Regimeire Freitas Aquino

    2013-02-01

    Full Text Available Rainfall erosivity is one of the main factors related to water erosion in the tropics. This work focused on relating soil loss from a typic dystrophic Tb Haplic Cambisol (CXbd and a typic dystrophic Red Latosol (LVdf to different patterns of natural erosive rainfall. The experimental plots of approximately 26 m² (3 x 8.67 m consisted of a CXbd area with a 0.15 m m-1 slope and a LVdf area with 0.12 m m-1 slope, both delimited by galvanized plates. Drainpipes were installed at the lower part of these plots to collect runoff, interconnected with a Geib or multislot divisor. To calculate erosivity (EI30, rainfall data, recorded continuously at a weather station in Lavras, were used. The data of erosive rainfall events were measured (10 mm precipitation intervals, accuracy 0.2 mm, 24 h period, 20 min intervals, characterized as rainfall events with more than 10 mm precipitation, maximum intensity > 24 mm h-1 within 15 min, or kinetic energy > 3.6 MJ, which were used in this study to calculate the rainfall erosivity parameter, were classified according to the moment of peak precipitation intensity in advanced, intermediate and delayed patterns. Among the 139 erosive rainfall events with CXbd soil loss, 60 % were attributed to the advanced pattern, with a loss of 415.9 Mg ha-1, and total losses of 776.0 Mg ha-1. As for the LVdf, of the 93 erosive rainfall events with soil loss, 58 % were listed in the advanced pattern, with 37.8 Mg ha-1 soil loss and 50.9 Mg ha-1 of total soil loss. The greatest soil losses were observed in the advanced rain pattern, especially for the CXbd. From the Cambisol, the soil loss per rainfall event was greatest for the advanced pattern, being influenced by the low soil permeability.

  2. Crust behavior and erosion rate prediction of EPR sacrificial material impinged by core melt jet

    Energy Technology Data Exchange (ETDEWEB)

    Li, Gen; Liu, Ming, E-mail: ming.liu@mail.xjtu.edu.cn; Wang, Jinshi; Chong, Daotong; Yan, Junjie

    2017-04-01

    Highlights: • A numerical code was developed to analyze melt jet-concrete interaction in the frame of MPS method. • Crust and ablated concrete layer at UO{sub 2}-ZrO{sub 2} melt and concrete interface periodically developed and collapsed. • Concrete surface temperature fluctuated around a low temperature and ablation temperature. • Concrete erosion by Fe-Zr melt jet was significantly faster than that by UO{sub 2}-ZrO{sub 2} melt jet. - Abstract: Sacrificial material is a special ferro-siliceous concrete, designed in the ex-vessel core melt stabilization system of European Pressurized water Reactor (EPR). Given a localized break of RPV lower head, the melt directly impinges onto the dry concrete in form of compact jet. The concrete erosion behavior influences the failure of melt plug, and further affects melt spreading. In this study, a numerical code was developed in the frame of Moving Particle Semi-implicit (MPS) method, to analyze the crust behavior and erosion rate of sacrificial concrete, impinged by prototypic melt jet. In validation of numerical modeling, the time-dependent erosion depth and erosion configuration matched well with the experimental data. Sensitivity study of sacrificial concrete erosion indicates that the crust and ablated concrete layer presented at UO{sub 2}-ZrO{sub 2} melt and concrete interface, whereas no crust could be found in the interaction of Fe-Zr melt with concrete. The crust went through stabilization-fracture-reformation periodic process, accompanied with accumulating and collapsing of molten concrete layer. The concrete surface temperature fluctuated around a low temperature and ablation temperature. It increased as the concrete surface layer was heated to melting, and dropped down when the cold concrete was revealed. The erosion progression was fast in the conditions of small jet diameter and large concrete inclination angle, and it was significantly faster in the erosion by metallic melt jet than by oxidic melt jet.

  3. Sediment reallocations due to erosive rainfall events in the Three Gorges Reservoir Area, Central China

    Science.gov (United States)

    Stumpf, Felix; Goebes, Philipp; Schmidt, Karsten; Schindewolf, Marcus; Schönbrodt-Stitt, Sarah; Wadoux, Alexandre; Xiang, Wei; Scholten, Thomas

    2017-04-01

    Soil erosion by water outlines a major threat to the Three Gorges Reservoir Area in China. A detailed assessment of soil conservation measures requires a tool that spatially identifies sediment reallocations due to rainfall-runoff events in catchments. We applied EROSION 3D as a physically based soil erosion and deposition model in a small mountainous catchment. Generally, we aim to provide a methodological frame that facilitates the model parametrization in a data scarce environment and to identify sediment sources and deposits. We used digital soil mapping techniques to generate spatially distributed soil property information for parametrization. For model calibration and validation, we continuously monitored the catchment on rainfall, runoff and sediment yield for a period of 12 months. The model performed well for large events (sediment yield>1 Mg) with an averaged individual model error of 7.5%, while small events showed an average error of 36.2%. We focused on the large events to evaluate reallocation patterns. Erosion occurred in 11.1% of the study area with an average erosion rate of 49.9Mgha 1. Erosion mainly occurred on crop rotation areas with a spatial proportion of 69.2% for 'corn-rapeseed' and 69.1% for 'potato-cabbage'. Deposition occurred on 11.0%. Forested areas (9.7%), infrastructure (41.0%), cropland (corn-rapeseed: 13.6%, potatocabbage: 11.3%) and grassland (18.4%) were affected by deposition. Because the vast majority of annual sediment yields (80.3%) were associated to a few large erosive events, the modelling approach provides a useful tool to spatially assess soil erosion control and conservation measures.

  4. Root characteristics of cover crops and their erosion-reducing potential during concentrated runoff

    Science.gov (United States)

    de Baets, S.; Poesen, J.

    2009-04-01

    In the loam region in central Belgium, a lot of research has been conducted on the effects of cover crops for preventing splash and interrill erosion and on their nutrient pumping effectiveness. As this is a very effective erosion and environment conservation technique, planting cover crops during the winter season is widely applied in the loess belt. Most of these cover crops freeze at the beginning of the winter period. Consequently, the above-ground biomass becomes less effective in protecting the soil from water erosion. Apart from the effects of the above-ground biomass in protecting the soil against raindrop impacts and reducing flow velocities by the retarding effects of their stems, plant roots also play an important role in improving soil strength. Previous research showed that roots contribute to a large extent to the resistance of topsoils against concentrated flow erosion. Unfortunately, information on root properties of common cover crops (e.g. Sinapis alba, Phacelia tanacetifoli, Lolium perenne, Avena sativa, Secale cereale, Raphanus sativus subsp. oleiferus) is very scarce. Therefore, root density distribution with depth and their erosion-reducing effects during concentrated flow erosion were assessed by conducting root auger measurements and concentrated flow experiments at the end of the growth period (December). The preliminary results indicate that the studied cover crops are not equally effective in preventing soil loss by concentrated flow erosion at the end of the growing season. Cover crops with thick roots, such as Sinapis alba and Raphanus sativus subsp. oleiferus are less effective than cover crops with fine-branched roots such as Phacelia tanacetifoli, Lolium perenne (Ryegrass), Avena sativa (Oats) and Secale cereale (Rye) in preventing soil losses by concentrated flow erosion. These results enable soil managers to select the most suitable crops and maximize soil protection.

  5. O factor de coberto vegetal, para árvores e Arbustos, em modelos de erosão hídrica The vegetation cover factor, for tree and bush canopies, in models of water erosion

    Directory of Open Access Journals (Sweden)

    Carla Rolo Antunes

    2011-07-01

    Full Text Available O objectivo primordial do presente trabalho consiste na análise do comportamento de cobertos arbóreos e arbustivos, em termos do processo de intercepção da precipitação, designadamente, retenção e gotejo, e no estabelecimento de uma componente a incluir em modelos de erosão, que permita quantificar o factor de coberto vegetal em caso de ocupação do solo por estes cobertos, associados a culturas arvenses, em subcoberto, particularmente, na Equação Universal da Perda de Solo Revista (RUSLE. O trabalho experimental utilizou um simulador de chuva, tendo-se obtido valores do diâmetro das gotas (gotejo das folhas de espécies características dos sistemas de uso do solo mais comuns no Sul de Portugal, nomeadamente sobreiro (Quercus suber L., azinheira (Quercus ilex L. ssp. rotundifolia Lam e carrasco (Quercus coccifera L., e quantificado valores de retenção nas folhas. A partir dos resultados obtidos estimou-se a energia cinética para diferentes alturas de queda e, consequentemente, valores correctivos a aplicar aos valores de C tradicionalmente considerados, relativos às culturas agrícolas.The main objective of this work consists on the analyzes of tree and bush canopies behavior, in terms of the rainfall interception process, namely, leave retention, and dripping, and the establishment of a erosion model component to include in to quantify the cover factor (C of the Revised Universal Soil Loss Equation (RUSLE for mixed land covered systems with arable crops, in association with trees and bushes. In the experimental work a rainfall simulator was used and the characteristic values for the diameter of the dripping drops and retention of the leaves from characteristic species of the more common mixed land-use systems in Southern of Portugal, particularly with Cork oak (Quercus suber L., Holm or evergreen oak (Quercus ilex L. ssp. rotundifolia Lam and Kermes or wild oak (Quercus coccifera L., were obtained. From the obtained results

  6. EROSION RATE OF RESERVOIR DEPOSIT AS REVEALED BY LABORATORY EXPERIMENT

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    A. S. Amar

    2012-06-01

    Full Text Available The construction of dams and reservoirs in a river can give significant impacts on its flow of water and sediment, and can cause long-term morphological changes on the river. Reservoir sedimentation can reduce a reservoir’s effective flood control volume, and in some severe cases can cause overtopping during floods. Sediment deposition against a dam can reduce its stability, and affect the operation of low-level outlet works, gates, and valves. The abrasive action of sediment particles can roughen the surface of release facilities and can cause cavitations and vibration. Sedimentation can also affect a reservoir’s water quality, and reduce its flood control, water supply, hydropower, and recreation benefits. Consequently, taking sedimentation into consideration not only in the planning and design, but also in the operation and maintenance of a dam and reservoir is important. Keywords: Erosion rate, reservoir deposit, shear stress.

  7. Helicobacter Pylori Eradication Therapy in both Erosive and Non-erosive Gastritis — A Prospective Study

    Directory of Open Access Journals (Sweden)

    Mohammad Quamrul Hasan

    2014-01-01

    Full Text Available Background: Infection with Helicobacter pylori (H. pylori is a recognized cause of peptic ulcer and gastritis. Persistence of infection is a definite risk factor for gastric malignancy. Healing of gastritis after eradication of H. pylori reduces the risks of peptic ulcer disease and gastric malignancy. Objectives: To find out the relationship of H. pylori with erosive and nonerosive gastritis, the effect of anti-H. pylori therapy and to compare the effects of anti-H. pylori therapy between two types of gastritis. Materials and Methods: This prospective study was done in the Gastroenterology department of Bangabandhu Sheikh Mujib Medical University, Dhaka from June 2008 to May 2009. One hundred eighty dyspeptic patients were enrolled for the study. Patients with gastritis diagnosed by endoscopy underwent rapid urease test (RUT. RUT positive patients were considered to have H. pylori infection and were treated with triple therapy (omeprazole, amoxycillin and metronidiazole for 14 days. Treatment responses were assessed by clinical history and also by endoscopic biopsy and RUT. Results of endoscopic findings and RUT after treatment were compared with pretreatment status. Results: Seventy patients completed the treatment and finally could be assessed. Endoscopic findings of 70 patients revealed that 56 (80% patients had erosive gastritis and 14 (20% patients had nonerosive gastritis. After treatment, 47 (67.1% lesions became normal, 16 (22.9% remained erosive and 7 (10% non-erosive as before. Out of 14 non-erosive diseases, 7 became normal, while out of 56 erosive diseases 40 became normal. The erosive group responded significantly better than the non-erosive group (c2=32.766, p<0.001. Fifty nine (84.3% patients with gastritis showed negative urease test after treatment. Conclusion: Strong relation between H. pylori infection and gastritis was found. Majority were antral erosive gastritis. Erosive group responded better than non-erosive group.

  8. Annotated bibliography on soil erosion and erosion control in subarctic and high-latitude regions of North America.

    Science.gov (United States)

    C.W. Slaughter; J.W. Aldrich

    1989-01-01

    This annotated bibliography emphasizes the physical processes of upland soil erosion, prediction of soil erosion and sediment yield, and erosion control. The bibliography is divided into two sections: (1) references specific to Alaska, the Arctic and subarctic, and similar high-latitude settings; and (2) references relevant to understanding erosion, sediment production...

  9. Predicting surfacing internal erosion in moraine core dams

    OpenAIRE

    Rönnqvist, Hans

    2010-01-01

    Dams that comprise broadly and widely graded glacial materials, such as moraines, have been found to be susceptible to internal erosion, perhaps more than dams of other soil types. Internal erosion washes out fine-grained particles from the filling material; the erosion occurs within the material itself or at an interface to another dam zone, depending on the mode of initiation. Whether or not internal erosion proceeds depend on the adequacy of the filter material. If internal erosion is allo...

  10. Erosion of sodium bentonite by flow and colloid diffusion

    Science.gov (United States)

    Moreno, Luis; Liu, Longcheng; Neretnieks, Ivars

    Smectite gel formed at the outer part of a bentonite buffer in granitic rock could expand into rock fractures with seeping water. Such a gel can release colloids into low ionic strength waters. In addition the gel/sol can itself slowly flow downstream when it has reached a low particle concentration sufficient to decrease the viscosity to allow flow. The erosion due to the combined effects of particle diffusion and gel/sol flow is modelled for a thin fracture into which the gel expands influenced by various forces between and on particles. Some of the forces such as the electrical double layer force and viscous force are strongly influenced by the ionic strength of the pore water. Changes in the ionic strength due to diffusion and dilution of ions in the expanding clay are modelled simultaneously with the gel expansion, flow of gel and colloid release to the seeping water. The model includes description of flow of the seeping fluid, which gradually turns from pure water to sol to more dense gel as the smectite source is approached. The model also describes expansion of the gel/sol and colloid release and flow and diffusion of ions in the system. The coupled models are solved using a numerical code. The results show that the gel will flow with a non-negligible flowrate when its volume fraction is below 1%, but that the erosion and loss of smectite is not much influenced by the concentration of sodium in