Demonstration of the Water Erosion Prediction Project (WEPP) internet interface and services

USDA-ARS?s Scientific Manuscript database

The Water Erosion Prediction Project (WEPP) model is a process-based FORTRAN computer simulation program for prediction of runoff and soil erosion by water at hillslope profile, field, and small watershed scales. To effectively run the WEPP model and interpret results additional software has been de...

Evaluation of compost blankets for erosion control from disturbed lands.

PubMed

Bhattarai, Rabin; Kalita, Prasanta K; Yatsu, Shotaro; Howard, Heidi R; Svendsen, Niels G

2011-03-01

Soil erosion due to water and wind results in the loss of valuable top soil and causes land degradation and environmental quality problems. Site specific best management practices (BMP) are needed to curb erosion and sediment control and in turn, increase productivity of lands and sustain environmental quality. The aim of this study was to investigate the effectiveness of three different types of biodegradable erosion control blankets- fine compost, mulch, and 50-50 mixture of compost and mulch, for soil erosion control under field and laboratory-scale experiments. Quantitative analysis was conducted by comparing the sediment load in the runoff collected from sloped and tilled plots in the field and in the laboratory with the erosion control blankets. The field plots had an average slope of 3.5% and experiments were conducted under natural rainfall conditions, while the laboratory experiments were conducted at 4, 8 and 16% slopes under simulated rainfall conditions. Results obtained from the field experiments indicated that the 50-50 mixture of compost and mulch provides the best erosion control measures as compared to using either the compost or the mulch blanket alone. Laboratory results under simulated rains indicated that both mulch cover and the 50-50 mixture of mulch and compost cover provided better erosion control measures compared to using the compost alone. Although these results indicate that the 50-50 mixtures and the mulch in laboratory experiments are the best measures among the three erosion control blankets, all three types of blankets provide very effective erosion control measures from bare-soil surface. Results of this study can be used in controlling erosion and sediment from disturbed lands with compost mulch application. Testing different mixture ratios and types of mulch and composts, and their efficiencies in retaining various soil nutrients may provide more quantitative data for developing erosion control plans. Copyright © 2010 Elsevier

Can control of soil erosion mitigate water pollution by sediments?

PubMed

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

Evaluation of erosion control blanket properties and test criteria for specification and design : final report.

DOT National Transportation Integrated Search

2016-07-01

A research project to investigate the product approval, design process, and ongoing product evaluation of erosion control blankets : (ECBs) for the Missouri Department of Transportation (MoDOT) was conducted. An overview of federal and state environm...

Annotated bibliography on soil erosion and erosion control in subarctic and high-latitude regions of North America.

Treesearch

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...

Water Erosion Prediction Project (WEPP) model status and updates

USDA-ARS?s Scientific Manuscript database

This presentation will provide current information on the USDA-ARS Water Erosion Prediction Project (WEPP) model, and its implementation by the USDA-Forest Service (FS), USDA-Natural Resources Conservation Service (NRCS), and other agencies and universities. Most recently, the USDA-NRCS has begun ef...

Surface Erosion Control Techniques on Newly Constructed Forest Roads

Treesearch

Johnny M. Grace; John Wilhoit; Robert Rummer; Bryce Stokes

1999-01-01

A newly constructed forest road was treated with three erosion control treatments: wood excelsior erosion mat, native grass species, and exotic grass species. The study evaluates treatment methods on the basis of sediment reduction and runoff volume reduction compared to no treatment. The erosion mat treatment was most effective in mitigating erosion losses with a 98...

Climatic controls on the pace of glacier erosion

NASA Astrophysics Data System (ADS)

Koppes, Michele; Hallet, Bernard; Rignot, Eric; Mouginot, Jeremie; Wellner, Julia; Love, Katherine

2016-04-01

Mountain ranges worldwide have undergone large-scale modification due the erosive action of ice, yet the mechanisms that control the timing of this modification and the rate by which ice erodes remain poorly understood. Available data report a wide range of erosion rates from individual ice masses over varying timescales, suggesting that modern erosion rates exceed orogenic rates by 2-3 orders of magnitude. These modern rates are presumed to be due to dynamic acceleration of the ice masses during deglaciation and retreat. Recent numerical models have focused on replicating the processes that produce the geomorphic signatures of glacial landscapes. Central to these models is a simple quantitative index that relates erosion rate to ice dynamics and to climate. To provide such an index, we examined explicitly the factors controlling modern glacier erosion rates across climatic regimes. Holding tectonic history, bedrock lithology and glacier hypsometries relatively constant across a latitudinal transect from Patagonia to the Antarctic Peninsula, we find that modern, basin-averaged erosion rates vary by three orders of magnitude, from 1->10 mm yr-1 for temperate tidewater glaciers to 0.01-<0.1 mm yr-1 for polar outlet glaciers, largely as a function of temperature and basal thermal regime. Erosion rates also increase non-linearly with both the sliding speed and the ice flux through the ELA, in accord with theory. The general relationship between ice dynamics and erosion suggests that the erosion rate scales non-linearly with basal sliding speed, with an exponent n ≈ 2-2.62. Notably, erosion rates decrease by over two orders of magnitude between temperate and polar glaciers with similar ice discharge rates. The difference in erosion rates between temperate and colder glaciers of similar shape and size is primarily related to the abundance of meltwater accessing the bed. Since all glaciers worldwide have experienced colder than current climatic conditions, the 100-fold

Evaluation of erosion control techniques on forest roads

Treesearch

Johnny M. Grace; Bob Rummer; Bryce J. Stokes; J. Wilhoit

1998-01-01

The cutslope and fillslope on a newly constructed forest road on the Talladega National Forest near Heflin, AL were treated with three erosion control techniques: wood excelsior erosion mat, native grass species, and exotic grass species. Bare soil plots were used as the experimental controls. Total sediment yield was measured during the period 21 September 1995 to 18...

Virginia Erosion and Sediment Control Handbook. Standards, Criteria and Guidelines.

ERIC Educational Resources Information Center

Virginia State Soil and Water Conservation Commission, Richmond, VA.

Guidelines and technical standards for development of local erosion and sediment control programs and conservation standards to meet the goals established by the Virginia Erosion and Sediment Control law are presented in this handbook. Part I defines natural and manmade erosion, sedimentation, and the hazards of uncontrolled wear and damage to the…

Forest road erosion control using multiobjective optimization

Treesearch

Matthew Thompson; John Sessions; Kevin Boston; Arne Skaugset; David Tomberlin

2010-01-01

Forest roads are associated with accelerated erosion and can be a major source of sediment delivery to streams, which can degrade aquatic habitat. Controlling road-related erosion therefore remains an important issue for forest stewardship. Managers are faced with the task to develop efficient road management strategies to achieve conflicting environmental and economic...

Airphoto analysis of erosion control practices

NASA Technical Reports Server (NTRS)

Morgan, K. M.; Morris-Jones, D. R.; Lee, G. B.; Kiefer, R. W.

1980-01-01

The Universal Soil Loss Equation (USLE) is a widely accepted tool for erosion prediction and conservation planning. In this study, airphoto analysis of color and color infrared 70 mm photography at a scale of 1:60,000 was used to determine the erosion control practice factor in the USLE. Information about contour tillage, contour strip cropping, and grass waterways was obtained from aerial photography for Pheasant Branch Creek watershed in Dane County, Wisconsin.

Can we manipulate root system architecture to control soil erosion?

NASA Astrophysics Data System (ADS)

Ola, A.; Dodd, I. C.; Quinton, J. N.

2015-03-01

Soil erosion is a major threat to soil functioning. The use of vegetation to control erosion has long been a topic for research. Much of this research has focused on the above ground properties of plants, demonstrating the important role that canopy structure and cover plays in the reduction of water erosion processes. Less attention has been paid to plant roots. Plant roots are a crucial yet under-researched factor for reducing water erosion through their ability to alter soil properties, such as aggregate stability, hydraulic function and shear strength. However, there have been few attempts to manipulate plant root system properties to reduce soil erosion. Therefore, this review aims to explore the effects that plant roots have on soil erosion and hydrological processes, and how plant root architecture might be manipulated to enhance its erosion control properties. We clearly demonstrate the importance of root system architecture for the control of soil erosion. We also demonstrate that some plant species respond to nutrient enriched patches by increasing lateral root proliferation. The soil response to root proliferation will depend upon its location: at the soil surface dense mats of roots may block soil pores thereby limiting infiltration, enhancing runoff and thus erosion; whereas at depth local increases in shear strength may reinforce soils against structural failure at the shear plane. Additionally, in nutrient deprived regions, root hair development may be stimulated and larger amounts of root exudates released, thereby improving aggregate stability and decreasing erodibility. Utilising nutrient placement at depth may represent a potentially new, easily implemented, management strategy on nutrient poor agricultural land or constructed slopes to control erosion, and further research in this area is needed.

Can we manipulate root system architecture to control soil erosion?

NASA Astrophysics Data System (ADS)

Ola, A.; Dodd, I. C.; Quinton, J. N.

2015-09-01

Soil erosion is a major threat to soil functioning. The use of vegetation to control erosion has long been a topic for research. Much of this research has focused on the above-ground properties of plants, demonstrating the important role that canopy structure and cover plays in the reduction of water erosion processes. Less attention has been paid to plant roots. Plant roots are a crucial yet under-researched factor for reducing water erosion through their ability to alter soil properties, such as aggregate stability, hydraulic function and shear strength. However, there have been few attempts to specifically manipulate plant root system properties to reduce soil erosion. Therefore, this review aims to explore the effects that plant roots have on soil erosion and hydrological processes, and how plant root architecture might be manipulated to enhance its erosion control properties. We demonstrate the importance of root system architecture for the control of soil erosion. We also show that some plant species respond to nutrient-enriched patches by increasing lateral root proliferation. The erosional response to root proliferation will depend upon its location: at the soil surface dense mats of roots may reduce soil erodibility but block soil pores thereby limiting infiltration, enhancing runoff. Additionally, in nutrient-deprived regions, root hair development may be stimulated and larger amounts of root exudates released, thereby improving aggregate stability and decreasing erodibility. Utilizing nutrient placement at specific depths may represent a potentially new, easily implemented, management strategy on nutrient-poor agricultural land or constructed slopes to control erosion, and further research in this area is needed.

Urban Runoff: Model Ordinances for Erosion and Sediment Control

EPA Pesticide Factsheets

The model ordinance in this section borrows language from the erosion and sediment control ordinance features that might help prevent erosion and sedimentation and protect natural resources more fully.

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

USDA-ARS?s Scientific Manuscript database

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...

18 CFR 1304.202 - General sediment and erosion control provisions.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 18 Conservation of Power and Water Resources 2 2011-04-01 2011-04-01 false General sediment and erosion control provisions. 1304.202 Section 1304.202 Conservation of Power and Water Resources TENNESSEE...). (c) Disturbed sites must be promptly stabilized with seeding, vegetative planting, erosion control...

18 CFR 1304.202 - General sediment and erosion control provisions.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false General sediment and erosion control provisions. 1304.202 Section 1304.202 Conservation of Power and Water Resources TENNESSEE...). (c) Disturbed sites must be promptly stabilized with seeding, vegetative planting, erosion control...

48 CFR 436.574 - Control of erosion, sedimentation, and pollution.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., sedimentation, and pollution. 436.574 Section 436.574 Federal Acquisition Regulations System DEPARTMENT OF... 436.574 Control of erosion, sedimentation, and pollution. The contracting officer shall insert the clause at 452.236-74, Control of Erosion, Sedimentation and Pollution, if there is a need for applying...

48 CFR 436.574 - Control of erosion, sedimentation, and pollution.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., sedimentation, and pollution. 436.574 Section 436.574 Federal Acquisition Regulations System DEPARTMENT OF... 436.574 Control of erosion, sedimentation, and pollution. The contracting officer shall insert the clause at 452.236-74, Control of Erosion, Sedimentation and Pollution, if there is a need for applying...

48 CFR 436.574 - Control of erosion, sedimentation, and pollution.

Code of Federal Regulations, 2013 CFR

2013-10-01

..., sedimentation, and pollution. 436.574 Section 436.574 Federal Acquisition Regulations System DEPARTMENT OF... 436.574 Control of erosion, sedimentation, and pollution. The contracting officer shall insert the clause at 452.236-74, Control of Erosion, Sedimentation and Pollution, if there is a need for applying...

48 CFR 436.574 - Control of erosion, sedimentation, and pollution.

Code of Federal Regulations, 2014 CFR

2014-10-01

..., sedimentation, and pollution. 436.574 Section 436.574 Federal Acquisition Regulations System DEPARTMENT OF... 436.574 Control of erosion, sedimentation, and pollution. The contracting officer shall insert the clause at 452.236-74, Control of Erosion, Sedimentation and Pollution, if there is a need for applying...

48 CFR 436.574 - Control of erosion, sedimentation, and pollution.

Code of Federal Regulations, 2012 CFR

2012-10-01

..., sedimentation, and pollution. 436.574 Section 436.574 Federal Acquisition Regulations System DEPARTMENT OF... 436.574 Control of erosion, sedimentation, and pollution. The contracting officer shall insert the clause at 452.236-74, Control of Erosion, Sedimentation and Pollution, if there is a need for applying...

Grass seeding as a control for roadbank erosion.

Treesearch

A.G. Wollum

1962-01-01

Grass, seeded on a steep roadcut in western Oregon, reduced erosion but caused increased surface runoff during a 3-year period of observation. These results were obtained at H. J. Andrews Experimental Forest from a study designed to measure effectiveness of grass in controlling soil erosion from exposed roadbanks. Additional measurements for varying soil types will be...

Erosion control on logging roads in the Appalachians

Treesearch

James N. Kochenderfer; James N. Kochenderfer

1970-01-01

In the steep terrain of the Appalachian Mountains much damage to forest streams is caused by erosion on logging roads. Muddy water that is unsuitable for fish, swimming, or human consumption often can be traced to these eroding roads. This paper has been prepared to sum up what land managers know about preventing and controlling erosion on logging roads in the...

A Comparison of Erosion and Water Pollution Control Strategies for an Agricultural Watershed

NASA Astrophysics Data System (ADS)

Prato, Tony; Shi, Hongqi

1990-02-01

The effectiveness and efficiency of two erosion control strategies and one water pollution control (riparian) strategy are compared for Idaho's Tom Beall watershed. Erosion control strategies maximize annualized net returns per hectare on each field and restrict field erosion rates to no more than 11.2 or 16.8 tons per hectare. The riparian strategy uses good vegetative cover on all fields adjacent to the creek and in noncropland areas and the resource management system that maximizes annualized net returns per hectare on remaining fields. The Agricultural Nonpoint Source Pollution model is used to simulate the levels and concentrations of sediment, nitrogen, phosphorus, and chemical oxygen demand at the outlet of the watershed. Erosion control strategies generate less total erosion and water pollution but are less efficient than the riparian strategy. The riparian strategy is less equitable for farmers than the erosion control strategies.

Modeling streamflow in a snow-dominated forest watershed using the Water Erosion Prediction Project (WEPP) model

USDA-ARS?s Scientific Manuscript database

The Water Erosion Prediction Project (WEPP) model was originally developed for hillslope and small watershed applications. The model simulates complex interactive processes influencing erosion, such as surface runoff, soil-water changes, vegetation growth and senescence, and snow accumulation and me...

Waterline Erosion Control Essential To Streambank Rehabilitation

Treesearch

Dean H. Urie

1967-01-01

Tests of streambank erosion control measures on three Michigan streams have shown the key role of waterline stabilization. After undercutting was stopped, the upper banks were revegetated in 1 to 5 years depending on treatment. Without waterline control, all revegetation efforts were ineffective.

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

Treesearch

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,...

Using rainfall simulators to test wood shreddings for erosion control

Treesearch

James Gronier; Randy Foltz; Charlie Showers

2005-01-01

The U.S. Department of Agriculture Forest Service is considering alternative methods of erosion control when constructing roads, decommissioning roads, protecting lands burned by wildland fires, and reclaiming lands disturbed by other activities. This article is the second in a series of tech tips that discuss the use of wood shreddings for erosion control. The first...

Folly Beach, South Carolina. Survey Report on Beach Erosion Control and Hurricane Protection.

DTIC Science & Technology

1980-03-28

ADAlI1 709 CORPS OF ENGINEERS CHARLESTON SC CHARLESTON DISTRICT F/G 13/2 MAR DFOLLY BEACH, SOUTH CAROLINA SURVEY REPORT ON BEACH EROSION CONT--ETCU...Army Corps of Engineers Charleston District P.O. Box 919, Charleston, S.C. 29402 _____________ S. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM...ELEMENT. PROJECT, TASK AREA & WORK UNIT NUMBERS U.S. Army Corps of Engineers Charleston District P.O. Box 919, Charleston, S.C. 29402 1t. CONTROLLING

48 CFR 452.236-74 - Control of Erosion, Sedimentation, and Pollution.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., Sedimentation, and Pollution. 452.236-74 Section 452.236-74 Federal Acquisition Regulations System DEPARTMENT OF....236-74 Control of Erosion, Sedimentation, and Pollution. As prescribed in 436.574, insert the following clause: Control of Erosion, Sedimentation, and Pollution (NOV 1996) (a) Operations shall be...

48 CFR 452.236-74 - Control of Erosion, Sedimentation, and Pollution.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., Sedimentation, and Pollution. 452.236-74 Section 452.236-74 Federal Acquisition Regulations System DEPARTMENT OF....236-74 Control of Erosion, Sedimentation, and Pollution. As prescribed in 436.574, insert the following clause: Control of Erosion, Sedimentation, and Pollution (NOV 1996) (a) Operations shall be...

48 CFR 452.236-74 - Control of Erosion, Sedimentation, and Pollution.

Code of Federal Regulations, 2012 CFR

2012-10-01

..., Sedimentation, and Pollution. 452.236-74 Section 452.236-74 Federal Acquisition Regulations System DEPARTMENT OF....236-74 Control of Erosion, Sedimentation, and Pollution. As prescribed in 436.574, insert the following clause: Control of Erosion, Sedimentation, and Pollution (NOV 1996) (a) Operations shall be...

48 CFR 452.236-74 - Control of Erosion, Sedimentation, and Pollution.

Code of Federal Regulations, 2013 CFR

2013-10-01

..., Sedimentation, and Pollution. 452.236-74 Section 452.236-74 Federal Acquisition Regulations System DEPARTMENT OF....236-74 Control of Erosion, Sedimentation, and Pollution. As prescribed in 436.574, insert the following clause: Control of Erosion, Sedimentation, and Pollution (NOV 1996) (a) Operations shall be...

48 CFR 452.236-74 - Control of Erosion, Sedimentation, and Pollution.

Code of Federal Regulations, 2014 CFR

2014-10-01

..., Sedimentation, and Pollution. 452.236-74 Section 452.236-74 Federal Acquisition Regulations System DEPARTMENT OF....236-74 Control of Erosion, Sedimentation, and Pollution. As prescribed in 436.574, insert the following clause: Control of Erosion, Sedimentation, and Pollution (NOV 1996) (a) Operations shall be...

Use of palm-mat geotextiles for rainsplash erosion control

NASA Astrophysics Data System (ADS)

Bhattacharyya, R.; Fullen, M. A.; Davies, K.; Booth, C. A.

2010-07-01

Soil detachment by raindrop action (rainsplash erosion) is a very important subprocess of erosion by water. It is a particular problem in the UK as most soils are sandy or loamy sand in texture and lands have gentle to medium slope. However, few studies report potential rainsplash erosion control options under field conditions. Hence, the utilization of palm-mat geotextiles as a rainsplash erosion control technique was investigated at Hilton, east Shropshire, U.K. (52°33'5.7″ N, 2°19'18.3″ W). Geotextile-mats constructed from Borassus aethiopum (Borassus palm of West Africa) and Mauritia flexuosa (Buriti palm of South America) leaves are termed Borassus mats and Buriti mats, respectively. Two-year field experiments were conducted at Hilton to study the effects of emplacing Borassus and Buriti mats on rainsplash erosion of a loamy sand soil. Two sets (12 plots each) of experiments were established to study the effects of these mats on splash height and splash erosion. Splash height needs to be known to assess the transport mechanism of major soil fraction and its constituents on sloping land by rainsplash. In both sets, six randomly-selected plots were covered with mats, and the rest were bare. Results (during 22/01/2007‒23/01/2009; total precipitation = 1731.5 mm) show that Borassus mat-covered plots had ˜ 89% ( P < 0.001) less total splash erosion (2.97 kg m - 2 ) than bare plots (27.02 kg m - 2 ). Comparatively, mean splash height from Borassus mat-covered plots (0.12 m) was significantly ( P < 0.001) less than the bare plots, by ˜ 54%. However, Buriti mat-cover on bare plots had no significant ( P > 0.05) effect in rainsplash erosion control during that period, although plots with Buriti mats significantly ( P < 0.05) decreased splash height (by ˜ 18%) compared with bare plots (0.26 m). Buriti mats, probably due to their ˜ 43, 62 and 50% lower cover percentage (44%), mass per unit area (413 g - 2 ) and thickness (10 mm), respectively, compared with

Enhancements to the Water Erosion Prediction Project (WEPP) for modeling large snow-dominated mountainous forest watersheds

Treesearch

Anurag Srivastava; Joan Q. Wu; William J. Elliot; Erin S. Brooks

2015-01-01

The Water Erosion Prediction Project (WEPP) model, originally developed for hillslope and small watershed applications, simulates complex interactive processes influencing erosion. Recent incorporations to the model have improved the subsurface hydrology components for forest applications. Incorporation of channel routing has made the WEPP model well suited for large...

Two case studies in river naturalization: planform migration and bank erosion control

NASA Astrophysics Data System (ADS)

Abad, J. D.; Guneralp, I.; Rhoads, B. L.; Garcia, M. H.

2005-05-01

A sound understanding of river planform evolution and bank erosion control, along with integration of expertise from several disciplines is required for the development of predictive models for river naturalization. Over the last few years, several methodologies have been presented for naturalization projects, from purely heuristic to more advanced methods. Since the time and space scales of concern in naturalization vary widely, there is a need for appropriate tools at a variety of time and space scales. This study presents two case studies at different scales. The first case study describes the prediction of river planform evolution for a remeandering project based on a simplified two-dimensional hydrodynamic model. The second case study describes the applicability of a Computational Fluid Dynamics (CFD) model for evaluating the effectiveness of bank-erosion control structures in individual meander bends. Understanding the hydrodynamic influence of control structures on flow through bends allows accurate prediction of depositional and erosional distribution patterns, resulting in better assessment on river planform stability, especially for the case of natural complex systems. The first case study introduces a mathematical model for evolution of meandering rivers that can be used in remeandering projects. In United States in particular, several rivers have been channelized in the past causing environmental and ecological problems. Following Newton's third law, "for every action, there is a reaction", naturalization techniques evolve as natural reactive solutions to channelization. This model (herein referred as RVR Meander) can be used as a stand-alone Windows application or as module in a Geographic Information System. The model was applied to the Poplar Creek re-meanderization project and used to evaluate re-meandering alternatives for an approximately 800-meter long reach of Poplar Creek that was straightened in 1938. The second case study describes a

Beach erosion control study at Pass Christian. [using remote sensors and satellite observation

NASA Technical Reports Server (NTRS)

1978-01-01

The methods of measuring the existence of erosion and the effects of sand stabilization control systems are described. The mechanics of sand movement, the nature of sand erosion, and the use of satellite data to measure these factors and their surrogates are discussed using the locational and control aspects of aeolian and litoral erosion zones along the sand beach of the Mississippi coast. The aeolian erosion is highlighted due to the redeposition of the sand which causes high cleanup costs, property damage, and safety and health hazards. The areas of differential erosion and the patterns of beach sand movement are illustrated and the use of remote sensing methods to identify the areas of erosion are evaluated.

Evaluation of erosion and siltation control fabrics.

DOT National Transportation Integrated Search

1976-01-01

New proprietary products in three areas of siltation and erosion control were evaluated. Hold/Gro and Griffnet materials were evaluated for use as slope stabilizers and were compared with the Department's present method of straw tacked with an asphal...

The success of headwater rehabilitation towards gully erosion control

NASA Astrophysics Data System (ADS)

Frankl, Amaury; Poesen, Jean; Nyssen, Jan

2017-04-01

The ill-management of headwaters has frequently shown to have adverse effects on both humans and the environment. Historical examples often refer to altered hydrological conditions and stream incision resulting from deforestation. Agricultural expansion and intensification - often accompanied with land reforms in the 20th century - also showed to severely impact the fluvial environment, with stream incision and gully erosion hazards increasingly affecting many headwater areas around the world. To counter this, many regions have adopted improved management schemes aiming at restoring the physical, biological and hydrological integrity of the soil- and landscape. In terms of hydrogeomorpology, the objective was to minimize dynamics to a lower level so that runoff, sediment and pollutant transfers do not cause danger to human life, environmental/natural resources deterioration or economic stress. Therefore, much attention was given to the rehabilitation and re-naturalization of headwater streams and gullies, which are the conduits of these transfers. This is done in both indirect and direct ways, i.e. reducing the delivery of runoff and sediment to the gullies and interventions in the incised channels. Although much has been published on gully erosion development and control, few studies assess the success of gully rehabilitation on the mid- to long term or confront results against the gully life-cycle. The latter refers to the rate law in fluvial geomorphology, whereby gully morphological changes (increases in length, area, volume) are initially rapid, followed by a much slower development towards a new equilibrium state. Here, we present a review of headwater rehabilitation measures and their success towards gully erosion control. By confronting this to the life-cycle of a gully, we also want to shed light on our understanding of when and where gully erosion control needs to be applied; making land management more efficient and effective. Keywords: land

A geographic information system to predict soil erosion potential in rural transportation construction project

DOT National Transportation Integrated Search

1995-06-30

Topographic surface modeling using a Geographic Information System (GIS) can be useful for the prediction of soil erosion resulting from highway construction projects. The assumption is that terrain, along with other parameters, will influence the po...

Wind erosion processes and control

USDA-ARS?s Scientific Manuscript database

Wind erosion continues to threaten the sustainability of our nations' soil, air, and water resources. To effectively apply conservation systems to prevent wind driven soil loss, an understanding of the fundamental processes of wind erosion is necessary so that land managers can better recognize the ...

Large-scale performance and design for construction activity erosion control best management practices.

PubMed

Faucette, L B; Scholl, B; Beighley, R E; Governo, J

2009-01-01

The National Pollutant Discharge Elimination System (NPDES) Phase II requires construction activities to have erosion and sediment control best management practices (BMPs) designed and installed for site storm water management. Although BMPs are specified on storm water pollution prevention plans (SWPPPs) as part of the construction general permit (GP), there is little evidence in the research literature as to how BMPs perform or should be designed. The objectives of this study were to: (i) comparatively evaluate the performance of common construction activity erosion control BMPs under a standardized test method, (ii) evaluate the performance of compost erosion control blanket thickness, (iii) evaluate the performance of compost erosion control blankets (CECBs) on a variety of slope angles, and (iv) determine Universal Soil Loss Equation (USLE) cover management factors (C factors) for these BMPs to assist site designers and engineers. Twenty-three erosion control BMPs were evaluated using American Society of Testing and Materials (ASTM) D-6459, standard test method for determination of ECB performance in protecting hill slopes from rainfall induced erosion, on 4:1 (H:V), 3:1, and 2:1 slopes. Soil loss reduction for treatments exposed to 5 cm of rainfall on a 2:1 slope ranged from-7 to 99%. For rainfall exposure of 10 cm, treatment soil loss reduction ranged from 8 to 99%. The 2.5 and 5 cm CECBs significantly reduced erosion on slopes up to 2:1, while CECBs < 2.5 cm are not recommended on slopes >or= 4:1 when rainfall totals reach 5 cm. Based on the soil loss results, USLE C factors ranged from 0.01 to 0.9. These performance and design criteria should aid site planners and designers in decision-making processes.

Gully erosion in Moldova: evolution, importance and control

NASA Astrophysics Data System (ADS)

Leah, Tamara

2017-04-01

land by reducing sudden decrease to the 1982 the index by gullies affection. The study of gullies intensity growth was achieved from 1966 in the main regions of Moldova. From 256 objects (gullies): 30% constitute those with weak growth (up to 0.3 m per year); 25% - with moderate growth (0.3-0.5 m) and 45% - with strong growth (0.5-1.5 m). There is no gully where would deprive their expansion process. Multiannual average growths of gullies are in large ranges - from 0.53 m on the Dniester Plateau to 1.48 m on the South Moldavian Plain. On the 1 January 2016 in the Republic of Moldova was registered 12031 hectares with gullies. Following active growth of depth erosion their total area annually increases with 300 hectares and the total destroyed land with 450-500 hectares. Linear and volume growth forecast of ravines (gullies) in different natural conditions of Moldova will be taken into consideration in designing of hydro-technical antierosion constructions and schemes to combat gullies erosion. Consequently, there is a need for erosion monitoring, special researches, experimental and modelling studies of gullies as a basis for predicting the effects of environmental change on gully erosion rates, implementation of measures to combat soil depth erosion in Moldova. Keywords: Agriculture activities, Erosion control, Gully erosion, Slope, Republic of Moldova

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

Treesearch

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...

Chosing erosion control nets. Can't you decide? Ask the lab.

NASA Astrophysics Data System (ADS)

Simkova, Jana; Jacka, Lukas

2015-04-01

Geotextiles (GTXs) have been used to protect steep slopes against soil erosion for about 60 years and many products have become available. The choice of individual product is always based on its ratio of cost versus effectiveness. Generally applicable recommendations for specific site conditions are missing and testing the effectiveness of GTXs in the field is time consuming and costly. Due to various site conditions, results of numerous case-studies cannot be generalized. One of the major and site-specific factors affecting the erosion process, and hence the effectiveness of GTXs, is the soil. This study aimed to determine the rate of influence of three natural erosion control nets on the volume and velocity of surface runoff caused by rainfall. The nets were installed on slope under laboratory conditions and then exposed to simulated rainfall. An impermeable plastic film was used as a substrate instead of soil to simulate non-infiltrating conditions. A comparison of the influence of tested GTX samples on surface runoff may indicate to their erosion control effect. Thus, the results could help with choosing a particular product. Under real conditions, the effect of erosion control nets would be increased by the infiltration capacity of the soil, equally for all samples. Therefore, the order of effectiveness of the samples should stay unchanged. To validate this theory, a field experiment was carried out where soil loss was recorded along with runoff characteristics. The data trends of discharge culmination under natural conditions were similar to trends under laboratory conditions and corresponded to soil loss records.

Wind tunnel experimental study on the effect of PAM on soil wind erosion control.

PubMed

He, Ji-Jun; Cai, Qiang-Guo; Tang, Ze-Jun

2008-10-01

In recent years, high-molecular-weight anionic polyacrylamide (PAM) have been widely tested on a variety of soils, primarily in water erosion control. However, little information is available regarding the effectiveness of PAM on preventing soil loss from wind erosion. The research adopted room wind tunnel experiment, two kinds of soils were used which were from the agro-pastoral area of Inner Mongolia, the northwest of China, the clay content of soils were 22.0 and 13.7%, respectively. For these tests, all the treatments were performed under the condition of wind velocity of 14 m s(-1) and a blown angle of 8.75%, according to the actual situation of experimented area. The study results indicated that using PAM on the soil surface could enhance the capability of avoiding the wind erosion, at the same time, the effect of controlling wind soil erosion with 4 g m(-2) PAM was better than 2 g m(-2) PAM's. Economically, the 2 g m(-2) PAM used in soil surface can control wind erosion effectively in this region. The prophase PAM accumulated in soil could not improve the capability of avoiding the wind erosion, owing to the degradation of PAM in the soil and the continual tillage year after year. The texture of soil is a main factor influencing the capability of soil avoiding wind erosion. Soil with higher clay content has the higher capability of preventing soil from wind erosion than one with the opposite one under the together action of PAM and water.

Soil erosion and sediment control laws. A review of state laws and their natural resource data requirements

NASA Technical Reports Server (NTRS)

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.

Fallout radionuclide-based techniques for assessing the impact of soil conservation measures on erosion control and soil quality: an overview of the main lessons learnt under an FAO/IAEA Coordinated Research Project.

PubMed

Dercon, G; Mabit, L; Hancock, G; Nguyen, M L; Dornhofer, P; Bacchi, O O S; Benmansour, M; Bernard, C; Froehlich, W; Golosov, V N; Haciyakupoglu, S; Hai, P S; Klik, A; Li, Y; Lobb, D A; Onda, Y; Popa, N; Rafiq, M; Ritchie, J C; Schuller, P; Shakhashiro, A; Wallbrink, P; Walling, D E; Zapata, F; Zhang, X

2012-05-01

This paper summarizes key findings and identifies the main lessons learnt from a 5-year (2002-2008) coordinated research project (CRP) on "Assessing the effectiveness of soil conservation measures for sustainable watershed management and crop production using fallout radionuclides" (D1.50.08), organized and funded by the International Atomic Energy Agency through the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture. The project brought together nineteen participants, from Australia, Austria, Brazil, Canada, Chile, China, Japan, Morocco, Pakistan, Poland, Romania, Russian Federation, Turkey, United Kingdom, United States of America and Vietnam, involved in the use of nuclear techniques and, more particularly, fallout radionuclides (FRN) to assess the relative impacts of different soil conservation measures on soil erosion and land productivity. The overall objective of the CRP was to develop improved land use and management strategies for sustainable watershed management through effective soil erosion control practices, by the use of ¹³⁷Cs (half-life of 30.2 years), ²¹⁰Pb(ex) (half-life of 22.3 years) and ⁷Be (half-life of 53.4 days) for measuring soil erosion over several spatial and temporal scales. The environmental conditions under which the different research teams applied the tools based on the use of fallout radionuclides varied considerably--a variety of climates, soils, topographies and land uses. Nevertheless, the achievements of the CRP, as reflected in this overview paper, demonstrate that fallout radionuclide-based techniques are powerful tools to assess soil erosion/deposition at several spatial and temporal scales in a wide range of environments, and offer potential to monitor soil quality. The success of the CRP has stimulated an interest in many IAEA Member States in the use of these methodologies to identify factors and practices that can enhance sustainable agriculture and minimize land degradation. Copyright �

Erosion control study : final report : Part II : roadside channels.

DOT National Transportation Integrated Search

1971-04-01

The objective of the study were: : 1) To evaluate present methods and develop new methods for establishing a permanent vegetative cover. : 2) To develop erosion control practices for existing highway drains and ditches. : 3) To develop highway bank s...

Estimating soil erosion risk and evaluating erosion control measures for soil conservation planning at Koga watershed in the highlands of Ethiopia

NASA Astrophysics Data System (ADS)

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

Validation of a probabilistic post-fire erosion model

Treesearch

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...

Bioengineering Technology to Control River Soil Erosion using Vetiver (Vetiveria Zizaniodes)

NASA Astrophysics Data System (ADS)

Sriwati, M.; Pallu, S.; Selintung, M.; Lopa, R.

2018-04-01

Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock or dissolved material from one location on the earth’s crust, and then transport it away to another location. Bioengineering is an attempt to maximise the use of vegetation components along riverbanks to cope with landslides and erosion of river cliffs and another riverbank damage. This study aims to analyze the bioengineering of Vetiver as a surface layer for soil erosion control using slope of 100, 200, and 300. This study is conducted with 3 variations of rain intensity (I), at 103 mm/hour, 107 mm/hour, and 130 mm/hour by using rainfall simulator tool. In addition, the USLE (Universal Soil Loss Equation) method is used in order to measure the rate of soil erosion. In this study, there are few USLE model parameters were used such as rainfall erosivity factor, soil erodibility factor, length-loss slope and stepness factor, cover management factor, and support practise factor. The results demonstrated that average of reduction of erosion rate using Vetiver, under 3 various rainfalls, namely rainfall intensity 103 mm/hr had reduced 84.971%, rainfall intensity 107 mm/hr had reduced 86.583 %, rainfall intensity 130 mm/hr had reduced 65.851%.

Erosion Control Techniques on Forest Road Cutslopes and Fillslopes in North Alabama

Treesearch

Johnny M. Grace

1999-01-01

Road cutslopes and fillslopes account for approximately 50 percent of the total road disturbance area on steep terrain and contribute as much as 60 percent of sediment from forest roads. The significance of erosion control techniques on these vulnerable components of the road prism has become evident in recent years. A study to gain a better understanding of erosion...

Geologic controls of erosion and sedimentation on Mars

NASA Technical Reports Server (NTRS)

Tanaka, K. L.; Dohm, J. M.; Carr, M. H.

1993-01-01

Because Mars has had a history of diverse erosional and depositional styles, a variety of erosional landforms and sedimentary deposits can be seen on Viking orbiter images. Here we review how geologic processes involving rock, water, and structure have controlled erosion and sedimentation on Mars. Additionally, we review how further studies will help refine our understanding of these processes.

High-Z material erosion and its control in DIII-D carbon divertor

DOE PAGES

Ding, Rui; Rudakov, Dimitry L.; Stangeby, Peter C.; ...

2017-03-16

It is expected that high-Z materials will be used as plasma-facing components (PFCs) in future fusion devices, making the erosion of high-Z material a key issue for high-power, long pulse operation. High-Z material erosion and redeposition have been studied using tungsten and molybdenum coated samples exposed in well-diagnosed DIII-D divertor plasma discharges. By coupling dedicated experiments and modelling using the 3D Monte Carlo code ERO, the roles of sheath potential and background carbon impurities in determining high-Z material erosion are identified. Different methods suggested by modelling have been investigated to control high-Z material erosion in DIII-D experiments. The erosion ofmore » Mo and W are found to be strongly suppressed by local injection of methane and deuterium gases. The 13C deposition resulting from local 13CH 4 injection also provides information on radial transport due to E×B drifts and cross field diffusion. Finally, D 2 gas puffing is found to cause 2 local plasma perturbation, suppressing W erosion because of the lower effective sputtering yield of W at lower plasma temperature and for higher carbon concentration in the mixed surface layer.« less

Erosion rates as a potential bottom-up control of forest structural characteristics in the Sierra Nevada Mountains.

PubMed

Milodowski, David T; Mudd, Simon M; Mitchard, Edward T A

2015-01-01

The physical characteristics of landscapes place fundamental constraints on vegetation growth and ecosystem function. In actively eroding landscapes, many of these characteristics are controlled by long-term erosion rates: increased erosion rates generate steeper topography and reduce the depth and extent of weathering, limiting moisture storage capacity and impacting nutrient availability. Despite the potentially important bottom-up control that erosion rates place on substrate characteristics, the relationship between the two is largely unexplored. We investigate spatial variations in aboveground biomass (AGB) across a structurally diverse mixed coniferous/deciduous forest with an order of magnitude erosion-rate gradient in the Northern Californian Sierra Nevada, USA, using high resolution LiDAR data and field plots. Mean basin slope, a proxy for erosion rate, accounts for 32% of variance in AGB within our field area (P < 0.001), considerably outweighing the effects of mean annual precipitation, temperature, and bedrock lithology. This highlights erosion rate as a potentially important, but hitherto unappreciated, control on AGB and forest structure.

An evaluation of the erosion-siltation control program of the Virginia Department of Highways, summer 1973.

DOT National Transportation Integrated Search

1974-01-01

During the summer of 1973 the authors conducted a statewide survey of the present state of the art of the Virginia Department of Highways' erosion and siltation control program. The survey included field observations of erosion and siltation control ...

Patterns and Controls of Erosion along the Elson Lagoon Coastline, Barrow, Alaska (2003-2016)

NASA Astrophysics Data System (ADS)

Tweedie, C. E.; Escarzaga, S. M.; Cody, R. P.; Manley, W. F.; Gaylord, A. G.; Aiken, Q.; Lopez, A. F.; Aguirre, A.; George, C.; Nelson, L.; Brown, J.

2016-12-01

With arctic warming and the combined effect of decreased summer sea ice extent, longer fetch for wave propagation, warmer sea surface and ground temperature, and longer periods of open water; the propensity for increased arctic coastal erosion rates and land-ocean sediment inputs to increase has been recognized for some time. In this study, we report on coastal erosion trends along a 11km stretch of coastline adjacent to the Barrow Environmental Observatory (BEO) where the position of the 2-4 meter high coastal bluff has been monitored annually with survey grade differential GPS (dGPS). Modern and historic erosion trends can be viewed through interactive web mapping applications at http://barrowmapped.org/. Rates of aerial and volumetric erosion losses averaged 0.7-2.8 meters and 0.8-3.5 cubic meters per meter of coast per year from 2003-2015 for each of the four coastal sections monitored. These losses equate to losses to the atmosphere and/or inputs to lagoon waters 53-220kgC per meter of coast per year. Such aerial losses are lower than from other areas of the Beaufort Sea coast that lack protective barrier islands, but 25-30% higher than historic decadal-scale change rates estimated for this section of coastline. However, regression analyses indicate no significant change to the rate of erosion during the past 13 years. Historic hotspots of erosion remained modern hotspots of erosion, and increases in modern erosion rates were greatest for sections of coast where historically high rates of erosion have been recorded. Regionally, the Elson Lagoon study area shows some of the highest rates of erosion for the Barrow Peninsula, which are generally 2-3 times mean annual erosion rates recorded for the Chukchi Sea Coastline near Barrow. Regression tree analysis used to isolate the relative importance of different biophysical controls of erosion differ between analyses run for aerial and volumetric losses along the Elson Lagoon Coast. These analyses also highlight key

Control of water erosion and sediment in open cut coal mines in tropical areas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ueda, T.; Nugraha, C.; Matsui, K.

2005-07-01

The purpose is to reduce the environmental impacts from open cut mining in tropical areas, such as Indonesia and Vietnam. Research conducted on methods for the control of water erosion and sediment from open cut coal mines is described. Data were collected on climate and weathering in tropical areas, mechanism of water erosion and sedimentation, characteristics of rocks in coal measures under wet conditions, water management at pits and haul roads and ramps, and construction of waste dumps and water management. The results will be applied to the optimum control and management of erosion and sediments in open cut mining.more » 6 refs., 8 figs.« less

Projected rainfall erosivity changes under climate change from multimodel and multiscenario projections in Northeast China

USDA-ARS?s Scientific Manuscript database

Future changes in precipitation will induce changes in the erosive power of rainfall and hence changes in soil erosion rates. In this study we calculated downscaled mean annual precipitation and USLE rainfall erosivity (R) for time periods 2030 through 2059 and 2070 through 2099 in Northeast China u...

Timing of dietary acid intake and erosive tooth wear: A case-control study.

PubMed

O'Toole, Saoirse; Bernabé, Eduardo; Moazzez, Rebecca; Bartlett, David

2017-01-01

There is a lack of clinical data on the impact of timing of dietary acid intake and toothbrush abrasion when attempting to control erosive tooth wear progression. The aim of this study was to estimate the association of theoretical causative factors with erosive tooth wear to inform evidence-based guidelines. Using case-control study design, 300 participants with dietary erosive tooth wear and 300 age-matched controls were recruited from the restorative clinics of King's College London Dental Institute. A previously validated questionnaire was adapted to be interviewer-led and to assess frequency, timing and duration of dietary acid intake in addition to alternate drinking habits prior to swallowing. Timing of toothbrushing in relation to meals and dietary acid intake was investigated. Associations with erosive tooth wear were assessed in crude and adjusted logistic regression models. Fruit intake between meals (p<0.001), but not with meals (p=0.206), was associated with erosive tooth wear and contrasted with acidic drinks which maintained a strong association regardless of timing of intake (OR up to 11.84 [95% CI: 5.42-25.89], p<0.001). Prolonged fruit eating and alternate drinking habits prior to swallowing (OR 12.82 [95% CI: 5.85-28.08] and 10.34 [95% CI: 4.85-22.06] respectively) were as strongly associated with erosive tooth wear as three or greater daily acid intakes (OR 10.92 [95% CI: 4.40-27.10]). Toothbrushing within 10min of acid intake was not associated with erosive tooth wear following adjustments for dietary factors (OR 1.41 [95% CI: 0.82-2.42], p=0.215]). Significantly increased odds ratios were observed when acids were consumed between meals in this cohort of patients. Universal advice to delay brushing after meals may not be substantiated. Prevention should be focused on avoiding dietary acids between meals, eliminating habits which increase contact time with the acid and reducing daily intake of acidic drinks. Toothbrushing after meals was not

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

NASA Astrophysics Data System (ADS)

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).

Evaluation of the serum zinc level in erosive and non-erosive oral lichen planus.

PubMed

Gholizadeh, N; Mehdipour, M; Najafi, Sh; Bahramian, A; Garjani, Sh; Khoeini Poorfar, H

2014-06-01

Lichen planus is a chronic inflammatory immunologic-based disease involving skin and mucosa. This disease is generally divided into two categories: erosive and non-erosive. Many etiologic factors are deliberated regarding the disease; however, the disorders of immune system and the role of cytotoxic T-lymphocytes and monocytes are more highlighted. Zinc is an imperative element for the growth of epithelium and its deficiency induces the cytotoxic activity of T-helper2 cells, which seems to be associated with lichen planus. This study was aimed to evaluate the levels of serum zinc in erosive and non-erosive oral lichen planus (OLP) and to compare it with the healthy control group to find out any feasible inference. A total of 22 patients with erosive oral lichen planus, 22 patients with non erosive OLP and 44 healthy individuals as the control group were recruited in this descriptive-comparative study. All the participants were selected from the referees to the department of oral medicine, school of dentistry, Tabriz University of Medical Sciences. Serum zinc level was examined for all the individuals with liquid-stat kit (Beckman Instruments Inc.; Carlsbad, CA). Data were analyzed by adopting the ANOVA and Tukey tests, using SPSS 16 statistical software. The mean age of patients with erosive and non-erosive LP was 41.7 and 41.3 years, respectively. The mean age of the healthy control group was 34.4 years .The mean serum zinc levels in the erosive and non erosive lichen planus groups and control groups were 8.3 (1.15), 11.15 (0.92) and 15.74 (1.75) μg/dl respectively. The difference was statistically significant (p< 0.05). The serum zinc levels were decreased in patients with erosive oral lichen planus. This finding may probably indicate the promising role of zinc in development of oral lichen planus.

A field experiment on the controls of sediment transport on bedrock erosion

NASA Astrophysics Data System (ADS)

Beer, A. R.; Turowski, J. M.; Fritschi, B.; Rieke-Zapp, D.; Campana, L.; Lavé, J.

2012-12-01

The earth`s surface is naturally shaped by interactions of physical and chemical processes. In mountainous regions with steep topography river incision fundamentally controls the geomorphic evolution of the whole landscape. There, erosion of exposed bedrock sections by fluvial sediment transport is an important mechanism forming mountain river channels. The links between bedload transport and bedrock erosion has been firmly established using laboratory experiments. However, there are only few field datasets linking discharge, sediment transport, impact energy and erosion that can be used for process understanding and model evaluation. To fill this gap, a new measuring setup has been commissioned to raise an appropriate simultaneous dataset of hydraulics, sediment transport and bedrock erosion at high temporal and spatial resolution. Two natural stone slabs were installed flush with the streambed of the Erlenbach, a gauged stream in the Swiss Pre-Alps. They are mounted upon force sensors recording vertical pressure und downstream shear caused by passing sediment particles. The sediment transport rates can be assessed using geophone plates and an automated moving basket system taking short-term sediment samples. These devices are located directly downstream of the stone slabs. Bedrock erosion rates are measured continuously with erosion sensors at sub-millimeter accuracy at three points on each slab. In addition, the whole slab topography is surveyed with photogrammetry and a structured-light 3D scanner after individual flood events. Since the installation in 2011, slab bedrock erosion has been observed during several transport events. We discuss the relation between hydraulics, bedload transport, resulting pressure forces on the stone slabs and erosion rates. The aim of the study is the derivation of an empirical process law for fluvial bedrock erosion driven by moving sediment particles.

Protection from erosion following wildfire

Treesearch

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...

Modeling erosion from forest roads with WEPP

Treesearch

J. McFero Grace

2007-01-01

Forest roads can be major sources of soil erosion from forest watersheds. Sediments from forest roads are a concern due to their potential delivery to stream systems resulting in degradation of water quality. The Water Erosion Prediction Project (WEPP) was used to predict erosion from forest road components under different management practices. WEPP estimates are...

Tempo-spatial downscaling of multiple GCMs projections for soil erosion risk analysis at El Reno, Oklahoma, USA

USDA-ARS?s Scientific Manuscript database

Proper spatial and temporal treatments of climate change scenarios projected by General Circulation Models (GCMs) are critical to accurate assessment of climatic impacts on natural resources and ecosystems. For accurate prediction of soil erosion risk at a particular farm or field under climate cha...

7Be and hydrological model for more efficient implementation of erosion control measure

NASA Astrophysics Data System (ADS)

Al-Barri, Bashar; Bode, Samuel; Blake, William; Ryken, Nick; Cornelis, Wim; Boeckx, Pascal

2014-05-01

Increased concern about the on-site and off-site impacts of soil erosion in agricultural and forested areas has endorsed interest in innovative methods to assess in an unbiased way spatial and temporal soil erosion rates and redistribution patterns. Hence, interest in precisely estimating the magnitude of the problem and therefore applying erosion control measures (ECM) more efficiently. The latest generation of physically-based hydrological models, which fully couple overland flow and subsurface flow in three dimensions, permit implementing ECM in small and large scales more effectively if coupled with a sediment transport algorithm. While many studies focused on integrating empirical or numerical models based on traditional erosion budget measurements into 3D hydrological models, few studies evaluated the efficiency of ECM on watershed scale and very little attention is given to the potentials of environmental Fallout Radio-Nuclides (FRNs) in such applications. The use of FRN tracer 7Be in soil erosion/deposition research proved to overcome many (if not all) of the problems associated with the conventional approaches providing reliable data for efficient land use management. This poster will underline the pros and cones of using conventional methods and 7Be tracers to evaluate the efficiency of coconuts dams installed as ECM in experimental field in Belgium. It will also outline the potentials of 7Be in providing valuable inputs for evolving the numerical sediment transport algorithm needed for the hydrological model on field scale leading to assess the possibility of using this short-lived tracer as a validation tool for the upgraded hydrological model on watershed scale in further steps. Keywords: FRN, erosion control measures, hydrological modes

Modeling streamflow in a snow-dominated forest watershed using the Water Erosion Prediction Project (WEPP) model

Treesearch

A. Srivastava; J. Q. Wu; W. J. Elliot; E. S. Brooks; D. C. Flanagan

2017-01-01

The Water Erosion Prediction Project (WEPP) model was originally developed for hillslope and small watershed applications. Recent improvements to WEPP have led to enhanced computations for deep percolation, subsurface lateral flow, and frozen soil. In addition, the incorporation of channel routing has made the WEPP model well suited for large watersheds with perennial...

Testing the control of mineral supply rates on chemical erosion in the Klamath Mountains

NASA Astrophysics Data System (ADS)

West, N.; Ferrier, K.

2017-12-01

The relationship between rates of chemical erosion and mineral supply is central to many problems in Earth science, including the role of tectonics in the global carbon cycle, nutrient supply to soils and streams via soil production, and lithologic controls on landscape evolution. We aim to test the relationship between mineral supply rates and chemical erosion in the forested uplands of the Klamath mountains, along a latitudinal transect of granodioritic plutons that spans an expected gradient in mineral supply rates associated with the geodynamic response to the migration of the Mendocino Triple Junction. We present 10Be-derived erosion rates and Zr-derived chemical depletion factors, as well as bulk soil and rock geochemistry on 10 ridgetops along the transect to test hypotheses about supply-limited and kinetically-limited chemical erosion. Previous studies in this area, comparing basin-averaged erosion rates and modeled uplift rates, suggest this region may be adjusted to an approximate steady state. Our preliminary results suggest that chemical erosion at these sites is influenced by both mineral supply rates and dissolution kinetics.

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

Treesearch

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...

Precise spatial control of cavitation erosion in a vessel phantom by using an ultrasonic standing wave.

PubMed

Shi, Aiwei; Huang, Peixuan; Guo, Shifang; Zhao, Lu; Jia, Yingjie; Zong, Yujin; Wan, Mingxi

2016-07-01

In atherosclerotic inducement in animal models, the conventionally used balloon injury is invasive, produces excessive vessel injuries at unpredictable locations and is inconvenient in arterioles. Fortunately, cavitation erosion, which plays an important role in therapeutic ultrasound in blood vessels, has the potential to induce atherosclerosis noninvasively at predictable sites. In this study, precise spatial control of cavitation erosion for superficial lesions in a vessel phantom was realised by using an ultrasonic standing wave (USW) with the participation of cavitation nuclei and medium-intensity ultrasound pulses. The superficial vessel erosions were restricted between adjacent pressure nodes, which were 0.87 mm apart in the USW field of 1 MHz. The erosion positions could be shifted along the vessel by nodal modulation under a submillimetre-scale accuracy without moving the ultrasound transducers. Moreover, the cavitation erosion of the proximal or distal wall could be determined by the types of cavitation nuclei and their corresponding cavitation pulses, i.e., phase-change microbubbles with cavitation pulses of 5 MHz and SonoVue microbubbles with cavitation pulses of 1 MHz. Effects of acoustic parameters of the cavitation pulses on the cavitation erosions were investigated. The flow conditions in the experiments were considered and discussed. Compared to only using travelling waves, the proposed method in this paper improves the controllability of the cavitation erosion and reduces the erosion depth, providing a more suitable approach for vessel endothelial injury while avoiding haemorrhage. Copyright © 2015 Elsevier B.V. All rights reserved.

Global carbon export from the terrestrial biosphere controlled by erosion.

PubMed

Galy, Valier; Peucker-Ehrenbrink, Bernhard; Eglinton, Timothy

2015-05-14

Riverine export of particulate organic carbon (POC) to the ocean affects the atmospheric carbon inventory over a broad range of timescales. On geological timescales, the balance between sequestration of POC from the terrestrial biosphere and oxidation of rock-derived (petrogenic) organic carbon sets the magnitude of the atmospheric carbon and oxygen reservoirs. Over shorter timescales, variations in the rate of exchange between carbon reservoirs, such as soils and marine sediments, also modulate atmospheric carbon dioxide levels. The respective fluxes of biospheric and petrogenic organic carbon are poorly constrained, however, and mechanisms controlling POC export have remained elusive, limiting our ability to predict POC fluxes quantitatively as a result of climatic or tectonic changes. Here we estimate biospheric and petrogenic POC fluxes for a suite of river systems representative of the natural variability in catchment properties. We show that export yields of both biospheric and petrogenic POC are positively related to the yield of suspended sediment, revealing that POC export is mostly controlled by physical erosion. Using a global compilation of gauged suspended sediment flux, we derive separate estimates of global biospheric and petrogenic POC fluxes of 157(+74)(-50) and 43(+61)(-25) megatonnes of carbon per year, respectively. We find that biospheric POC export is primarily controlled by the capacity of rivers to mobilize and transport POC, and is largely insensitive to the magnitude of terrestrial primary production. Globally, physical erosion rates affect the rate of biospheric POC burial in marine sediments more strongly than carbon sequestration through silicate weathering. We conclude that burial of biospheric POC in marine sediments becomes the dominant long-term atmospheric carbon dioxide sink under enhanced physical erosion.

The Monitoring Erosion of Agricultural Land and spatial database of erosion events

NASA Astrophysics Data System (ADS)

Kapicka, Jiri; Zizala, Daniel

2013-04-01

In 2011 originated in The Czech Republic The Monitoring Erosion of Agricultural Land as joint project of State Land Office (SLO) and Research Institute for Soil and Water Conservation (RISWC). The aim of the project is collecting and record keeping information about erosion events on agricultural land and their evaluation. The main idea is a creation of a spatial database that will be source of data and information for evaluation and modeling erosion process, for proposal of preventive measures and measures to reduce negative impacts of erosion events. A subject of monitoring is the manifestations of water erosion, wind erosion and slope deformation in which cause damaged agriculture land. A website, available on http://me.vumop.cz, is used as a tool for keeping and browsing information about monitored events. SLO employees carry out record keeping. RISWC is specialist institute in the Monitoring Erosion of Agricultural Land that performs keeping the spatial database, running the website, managing the record keeping of events, analysis the cause of origins events and statistical evaluations of keeping events and proposed measures. Records are inserted into the database using the user interface of the website which has map server as a component. Website is based on database technology PostgreSQL with superstructure PostGIS and MapServer UMN. Each record is in the database spatial localized by a drawing and it contains description information about character of event (data, situation description etc.) then there are recorded information about land cover and about grown crops. A part of database is photodocumentation which is taken in field reconnaissance which is performed within two days after notify of event. Another part of database are information about precipitations from accessible precipitation gauges. Website allows to do simple spatial analysis as are area calculation, slope calculation, percentage representation of GAEC etc.. Database structure was designed

Autonomous watersheds: Reducing flooding and stream erosion through real-time control

NASA Astrophysics Data System (ADS)

Kerkez, B.; Wong, B. P.

2017-12-01

We introduce an analytical toolchain, based on dynamical system theory and feedback control, to determine how many control points (valves, gates, pumps, etc.) are needed to transform urban watersheds from static to adaptive. Advances and distributed sensing and control stand to fundamentally change how we manage urban watersheds. In lieu of new and costly infrastructure, the real-time control of stormwater systems will reduce flooding, mitigate stream erosion, and improve the treatment of polluted runoff. We discuss the how open source technologies, in the form of wireless sensor nodes and remotely-controllable valves (open-storm.org), have been deployed to build "smart" stormwater systems in the Midwestern US. Unlike "static" infrastructure, which cannot readily adapt to changing inputs and land uses, these distributed control assets allow entire watersheds to be reconfigured on a storm-by-storm basis. Our results show how the control of even just a few valves within urban catchments (1-10km^2) allows for the real-time "shaping" of hydrographs, which reduces downstream erosion and flooding. We also introduce an equivalence framework that can be used by decision-makers to objectively compare investments into "smart" system to more traditional solutions, such as gray and green stormwater infrastructure.

Oesophageal mucosal intercellular space diameter and reflux pattern in childhood erosive and non-erosive reflux disease.

PubMed

Mancini, Valentina; Ribolsi, Mentore; Gentile, Massimo; de'Angelis, Gianluigi; Bizzarri, Barbara; Lindley, Keith J; Cucchiara, Salvatore; Cicala, Michele; Borrelli, Osvaldo

2012-12-01

We sought to compare intercellular space diameter in children with non-erosive and erosive reflux disease, and a control group. We also aimed to characterize the reflux pattern in erosive and non-erosive reflux disease patients, and to explore the relationship between intercellular space diameter values and reflux parameters. Twenty-four children with non-erosive reflux disease, 20 with erosive reflux disease, and 10 controls were prospectively studied. All patients and controls underwent upper endoscopy. Biopsies were taken at 2-3 cm above the Z-line, and intercellular space diameter was measured using transmission electron microscopy. Non-erosive and erosive reflux disease patients underwent impedance-pH monitoring. Mean intercellular space diameter values were significantly higher in both non-erosive (0.9 ± 0.2 μm) and erosive reflux disease (1 ± 0.2 μm) compared to controls (0.5 ± 0.2 μm, p<0.01). No difference was found between the two patient groups. Acid exposure time, the number of acid, weakly acidic and weakly alkaline reflux events did not differ between the two patient groups. No difference was found in the mean intercellular space diameter between non-erosive reflux disease children with and without abnormal acid exposure time (1 ± 0.3 vs. 0.9 ± 0.2 μm). No correlation was found between any reflux parameter and intercellular space diameter values. Dilated intercellular space diameter seems to be a useful and objective marker of oesophageal damage in paediatric gastro-oesophageal reflux disease, regardless of acid exposure. In childhood, different gastro-oesophageal reflux disease phenotypes cannot be discriminated on the basis of reflux pattern. Copyright © 2012 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

Erosion risk assessment along coastlines, rivers, and lakes

NASA Astrophysics Data System (ADS)

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

Developing the sediment and erosion control laboratory to become a hands-on training and education center.

DOT National Transportation Integrated Search

2013-11-01

The Sedimentation and Erosion Control (SEC) Laboratory has an established reputation as a renowned soil erosion research facility in the United States since its inception in 1990. During the past two decades, the lab has expanded its original perform...

Best management practices used by KYTC for on-site erosion control.

DOT National Transportation Integrated Search

2006-11-01

New erosion control procedures (ECP) have recently been implemented by the Kentucky Transportation Cabinet (KYTC). Previously, consultants and designers developed the ECP as a part of the design plans. In many cases these did not work in the field. T...

Performance-based specifications for temporary erosion and sediment control during construction : a survey of state practice.

DOT National Transportation Integrated Search

2013-03-01

During construction projects, surrounding soils can be disrupted, causing ecological damage through topsoil erosion and pollution of waterways with sediment. MnDOT currently has requirements and inspection procedures to ensure that contractors take m...

Dental Erosion in Industry

PubMed Central

Cate, H. J. Ten Bruggen

1968-01-01

Five hundred and fifty-five acid workers were examined between March 1962 and October 1964. One hundred and seventy-six (31·7%) were affected by industrial dental erosion at the first examinations. In 33 cases (6·0%) the dentine was affected. During the period of the survey, 66 (20·4%) of 324 workers examined more than once showed evidence that erosion was progressing. The prevalence and incidence of erosion were highest among battery formation workers, lower among picklers, and least among other processes covered by the survey. The age of workers did not appear to influence their susceptibility to erosion. The habit of working with the lips slightly parted had little effect. Erosion superimposed upon attrition predisposed to more severe loss of tooth structure than either operating alone. Little inconvenience or functional disability was suffered by acid workers due to erosion. Twenty-seven (23·7%) of 114 erosions were considered to be disfiguring. Regular dental treatment was sought less by acid workers than by controls, and the oral hygiene of the latter was superior. There was no evidence to show any difference between caries experience among acid workers and controls. Calculus and periodontal disease were more prevalent among acid workers than among controls, but it was not possible to attribute this to the working environment. Black staining in iron picklers was considered to be due to the working environment. The use of closed acid containers or lip extraction on open acid vats prevented significant atmospheric contamination and diminished the prevalence of erosion. The use of wall fans and detergent foaming agents was helpful. Images PMID:5723349

Fertilization To Accelerate Loblolly Pine Foliage Growth For Erosion Control

Treesearch

Paul D. Duffy

1977-01-01

On the southern Coastal Plain, loblolly pine (Pinus taeda L.) can be used to help control erosion because it produces abundant soil-protecting litter. The species requires several years to produce enough litter for adequate soil protection, but on loamy soils fertilization can reduce the time by a year or more. When five fertilizer combinations...

Sediment storage dam: A structural gully erosion control and sediment trapping measure, northern Ethiopia

NASA Astrophysics Data System (ADS)

Mekonnen, Mulatie; Keesstra, Saskia; Baartman, Jantiene; Ritsema, Coen

2014-05-01

Gully erosion is a prime problem in Ethiopia. This study assessed the severity of gully erosion and the role of sediment storage dams (SSD) in restoring gullies and preventing further gully development, its sediment trapping efficacy (STE) and its capacity in converting degraded gully lands to productive land. On average 2.5 m deep, 6.6 m wide and 28.3 m long gullies were formed in Minizr watershed, northwest Ethiopia, in 2013. Concentrated surface runoff, traditional ditches, graded terraces without suitable water ways and road construction are the main causes of such serious gully erosion. Over grazing, tunnel flow and lack of proper immediate gully treatment actions after gully initiation are found to be additional causes of the problem. Gully erosion was also found as the major source of sediment for downstream rivers and water reservoirs. The annual volume of soil eroded from only four gullies was 1941.3 m3. To control gully erosion, SSDs were found to be important physical structures, which can trap significant amount of sediment within gullies and they can convert unproductive gully land to productive agricultural land for fruit and crop production. Eight SSDs trapped about 44*103 m3 of sediment within 2 to 8 years. Two representative SSDs constructed using gabion and stone were tested for their STE. Results showed that their efficacy was 74.1% and 66.4% for the gabion and stone SSDs, respectively. Six of the older SSDs were already full of sediment and created 0.75 ha of productive land within 2 to 8 years. SSDs best fits to treat large size and deep gullies where other gully control measures, check dams, could not function well. To prevent gully formation, controlling its causes that is avoiding traditional ditches, practicing grassed water ways to safely remove runoff water from graded terraces, integrated watershed and road side management practices are important solutions. KEY WORDS: Sediment storage dam, gully erosion, sediment trapping efficacy

Modeling of high-Z materials erosion and its suppression in DIII-D

NASA Astrophysics Data System (ADS)

Ding, Rui; Guo, H. Y.; Chan, V. S.; Snyder, P. B.; Rudakov, D. L.; Stangeby, P. C.; Elder, J. D.; Tskhakaya, D.; Wampler, W. R.; Kirschner, A.; McLean, A. G.

2015-11-01

Erosion of plasma facing components is a key issue for high-power, long pulse operation. The 3D Monte Carlo code ERO has been used to simulate the erosion/redeposition of Mo and W samples exposed to DIII-D divertor plasma using the DiMES. The net erosion rate is significantly reduced due to the high local re-deposition ratio of eroded materials, which is mainly controlled by the electric field and plasma density within the Chodura sheath as indicated by ERO modeling. Similar re-deposition ratios were obtained from the modeling using three sheath models for small inclined magnetic field angle, all being close to the measured value. ERO modeling shows that local CH4 injection can create a carbon coating on the Mo sample to mitigate Mo erosion; the local decrease of electron temperature due to gas injection also suppresses net erosion, consistent with experimental observation. Supported by the US DOE under DE-FC02-04ER54698 and PSI-SciDAC project.

Effectiveness of Vegetation in Erosion Control From Forest Road Sideslopes

Treesearch

Johnny M. Grace

2002-01-01

Abstract.. Forest roads have been identified as the major contributor to sediment production from forested lands, accounting for perhaps as much as 90% of all sediment produced. In recent years, increased concern and societal pressure has focused on the impacts of forest roads and the effectiveness of erosion control measures. In addition, the re–...

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

NASA Astrophysics Data System (ADS)

Webb, N.; Herrick, J.; Duniway, M.

2013-12-01

This work explores how soil erosion assessments can be structured in the context of ecological sites and site dynamics to inform systems for managing accelerated soil erosion. We evaluated wind and water erosion rates for five ecological sites in southern New Mexico, USA, using monitoring data and rangeland-specific wind and water erosion models. Our results show that wind and water erosion can be highly variable within and among ecological sites. Plots in shrub-encroached and shrub-dominated states were consistently susceptible to both wind and water erosion. However, grassland plots and plots with a grass-succulent mix had a high indicated susceptibility to wind and water erosion respectively. Vegetation thresholds for controlling erosion are identified that transcend the ecological sites and their respective states. The thresholds define vegetation cover levels at which rapid (exponential) increases in erosion rates begin to occur, suggesting that erosion in the study ecosystem can be effectively controlled when bare ground cover is <20% of a site or total ground cover is >50%. Similarly, our results show that erosion can be controlled when the cover of canopy interspaces >50 cm in length reaches ~50%, the cover of canopy interspaces >100 cm in length reaches ~35% or the cover of canopy interspaces >150 cm in length reaches ~20%. This process-based understanding can be applied, along with knowledge of the differential sensitivity of vegetation states, to improve erosion management systems. 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 sites to erosion. Land use impacts that are constrained within the natural variability of sites should not result in accelerated soil erosion. Evaluating land condition against the erosion thresholds and natural variability of ecological sites will enable improved identification of where and when accelerated soil

Agriculture and stream water quality: A biological evaluation of erosion control practices

NASA Astrophysics Data System (ADS)

Lenat, David R.

1984-07-01

Agricultural runoff affects many streams in North Carolina. However, there is is little information about either its effect on stream biota or any potential mitigation by erosion control practices. In this study, benthic macroinvertebrates were sampled in three different geographic areas of North Carolina, comparing control watersheds with well-managed and poorly managed watersheds. Agricultural streams were characterized by lower taxa richness (especially for intolerant groups) and low stability. These effects were most evident at the poorly managed sites. Sedimentation was the apparent major problem, but some changes at agricultural sites implied water quality problems. The groups most intolerant of agricultural runoff were Ephemeroptera, Plecoptera and Trichoptera. Tolerant species were usually filter-feeders or algal grazers, suggesting a modification of the food web by addition of particulate organic matter and nutrients. This study clearly indicates that agricultural runoff can severely impact stream biota. However, this impact can be greatly mitigated by currently recommended erosion control practices.

Environmental stochasticity controls soil erosion variability

PubMed Central

Kim, Jongho; Ivanov, Valeriy Y.; Fatichi, Simone

2016-01-01

Understanding soil erosion by water is essential for a range of research areas but the predictive skill of prognostic models has been repeatedly questioned because of scale limitations of empirical data and the high variability of soil loss across space and time scales. Improved understanding of the underlying processes and their interactions are needed to infer scaling properties of soil loss and better inform predictive methods. This study uses data from multiple environments to highlight temporal-scale dependency of soil loss: erosion variability decreases at larger scales but the reduction rate varies with environment. The reduction of variability of the geomorphic response is attributed to a ‘compensation effect’: temporal alternation of events that exhibit either source-limited or transport-limited regimes. The rate of reduction is related to environment stochasticity and a novel index is derived to reflect the level of variability of intra- and inter-event hydrometeorologic conditions. A higher stochasticity index implies a larger reduction of soil loss variability (enhanced predictability at the aggregated temporal scales) with respect to the mean hydrologic forcing, offering a promising indicator for estimating the degree of uncertainty of erosion assessments. PMID:26925542

10Be Erosion Rates Controlled by Normal Fault Slip Rates and Transient Incision

NASA Astrophysics Data System (ADS)

Roda-Boluda, D. C.; D'Arcy, M. K.; Whittaker, A. C.; Allen, P.; Gheorghiu, D. M.; Rodés, Á.

2016-12-01

Quantifying erosion rates, and how they compare to rock uplift rates, is fundamental for understanding the evolution of relief and the associated sediment supply from mountains to basins. The trade-off between uplift and erosion is well-represented by river incision, which is often accompanied by hillslope steepening and landsliding. However, characterizing the relation between these processes and the impact that these have on sediment delivered to basins, remains a major challenge in many tectonically-active areas. We use Southern Italy as a natural laboratory to address these questions, and quantify the interplay of tectonics, geomorphic response and sediment export. We present 15 new 10Be catchment-averaged erosion rates, collected from catchments along five active normal faults with excellent slip rate constraints. We find that erosion rates are strongly controlled by fault slip rates and the degree of catchment incision. Our data suggests that overall 70% of the rock uplifted by the faults is being eroded, offering new insights into the topographic balance of uplift and erosion in this area. None of the erosion rates are greater than local fault slip rates, so fault activity is effectively establishing an upper limit on erosion. However, eight 10Be samples from low relief, unincised areas within the catchments, collected above knickpoints, yield consistent erosion rates of 0.12 mm/yr. In contrast, samples collected below knickpoints and below the incised sectors of the channels, have erosion rates of 0.2-0.8 mm/yr. The comparison allows us to quantify the impact that transient incisional response has on erosion rates. We show that incision is associated with frequent, shallow landsliding, and we find that the volumes of landslides stored on the catchments are highly correlated with 10Be-derived sediment flux estimates, suggesting that landslides are likely to be a major contributor to sediment fluxes; and we examine the implications that this may have on 10Be

Use of hold-gro erosion control fabric in the establishment of plant species on coal mine soil.

PubMed

Day, A D; Ludeke, K L

1986-09-01

Experiments were conducted on the Black Mesa Coal Mine, Kayenta, Arizona in 1977 and 1978 to study the effectiveness of Hold-Gro Erosion Control Fabric (a product from the Gulf States Paper Corporation, Tuscaloosa, Alabama) in the establishment of plants on coal mine soil following the surface mining of coal. Four plant species were planted: (1) spring barley (Horduem vulgare L.), an annual grass (2) crested wheatgrass (Agropyron cristatum L.), a perennial grass (3) alfalfa (lucerne) (Medicago sativa L.), a perennial legume and (4) fourwing saltbush (Atriplex canescens Pursh.), a perennial shrub. Seeds of each plant species were planted in reclaimed coal mine soil in the spring of the year by both broadcast seeding (conventional culture) and the incorporation of seeds in Hold-Gro Erosion Control Fabric. Average numbers of seedlings established and percent ground cover for all species studied were higher in areas where conventional culture was used than they were in areas where seeds were incorporated in Hold-Gro Erosion Control Fabric. The incorporation of seeds in Hold-Gro Erosion Control Fabric in the establishment of plant species on coal mine soil was not an effective cultural practice in the southwestern United States.

Effects of polyacrylamide on soil erosion and nutrient losses from substrate material in steep rocky slope stabilization projects.

PubMed

Chen, Zhang; Chen, Wenlu; Li, Chengjun; Pu, Yanpin; Sun, Haifeng

2016-06-01

Erosion of denuded steep rocky slopes causes increasing losses of nitrogen and phosphorus, which is a severe problem in rocky slope protection. Thus, it is important to determine the appropriate materials that can reduce the erodibility and losses of nitrogen and phosphorus of the soil. In this paper, twenty-seven simulated rainfall events were carried out in a greenhouse, in which the substrate material was artificial soil; nine types of anionic polyacrylamide (PAM) were studied, which consisted of three molecular weight (6, 12, and 18 Mg mol(-1)) and three charge density (10, 20, and 30%) formulations in a 3 by 3 factorial design. The results showed that: (1) Polyacrylamide application reduced total nitrogen losses by 35.3% to 50.0% and total phosphorus losses by 34.9% to 48.0% relative to the control group. (2) The losses of total nitrogen and total phosphorus had significant correlation with the molecular weight. Besides, the losses of total phosphorus, particulate-bound phosphorus and inorganic nitrogen (NH4-N) were significantly correlated with their molecular weight and charge density. However, the losses of dissolved organic nitrogen, inorganic nitrogen (NO3-N), dissolved organic phosphorus, inorganic phosphorus (PO4-P) were non-significantly correlated with molecular weight and charge density. (3) Particulate-bound nitrogen and phosphorus were responsible for the losses of nitrogen and phosphorus during runoff events, where particulate-bound nitrogen made up 71.7% to 73.2% of total nitrogen losses, and particulate-bound phosphorus made up 82.3% to 85.2% of total phosphorus losses. (4) Polyacrylamide treatments increased water-stable aggregates content by 32.3% to 59.1%, total porosity by 11.3% to 49.0%, final infiltrative rate by 41.3% to 72.5%, and reduced soil erosion by 18.9% to 39.8% compared with the control group. Overall, the results of this study indicated that polyacrylamide application in the steep rocky slope stabilization projects could

Composition of enamel pellicle from dental erosion patients.

PubMed

Carpenter, G; Cotroneo, E; Moazzez, R; Rojas-Serrano, M; Donaldson, N; Austin, R; Zaidel, L; Bartlett, D; Proctor, G

2014-01-01

Oral health is dependent upon a thin mobile film of saliva on soft and hard tissues. Salivary proteins adhere to teeth to form the acquired enamel pellicle which is believed to protect teeth from acid erosion. This study investigated whether patients suffering diet-induced dental erosion had altered enamel pellicles. Thirty patients suffering erosion were compared to healthy age-matched controls. Subjects wore a maxillary splint holding hydroxyapatite and human enamel blocks for 1 h. The acquired enamel pellicle was removed from the blocks and compared to the natural incisor pellicle. Basic Erosive Wear Examination scores confirmed that dental erosion was present in erosion patients and absent from healthy age-matched controls. Erosion patients had half the amount of proteins (BCA assay) within the acquired pellicle forming on splint blocks compared to normal controls (p < 0.05). In particular, statherin, a calcium-binding protein, was 35% less abundant (p < 0.05). Calcium concentration within the acquired pellicle was also reduced by 50% in erosion patients (p < 0.001). In contrast, the natural pellicle on the incisor had similar amounts of total protein in erosion patients and healthy controls. In summary, the formation of new acquired pellicles on surfaces was reduced in erosion patients, which may explain their greater susceptibility to acid erosion of teeth. © 2014 S. Karger AG, Basel.

Impacts of terracing on soil erosion control and crop yield in two agro-ecological zones of Rwanda

NASA Astrophysics Data System (ADS)

Rutebuka, Jules; Ryken, Nick; Uwimanzi, Aline; Nkundwakazi, Olive; Verdoodt, Ann

2017-04-01

Soil erosion remains a serious limiting factor to the agricultural production in Rwanda. Terracing has been widely adopted in many parts of the country in the past years, but its effectiveness is not yet known. Besides the standard radical (bench) terraces promoted by the government, also progressive terraces (with living hedges) become adopted mainly by the farmers. The aim of this study was to measure short-term (two consecutive rainy seasons 2016A and 2016B) run-off and soil losses for existing radical (RT) and progressive (PT) terraces versus non-protected (NP) fields using erosion plots installed in two agro-ecological zones, i.e. Buberuka highlands (site Tangata) and Eastern plateau (site Murehe) and determine their impacts on soil fertility and crop production. The erosion plot experiment started with a topsoil fertility assessment and during the experiment, maize was grown as farmer's cropping preference in the area. Runoff data were captured after each rainfall event and the collected water samples were dried to determine soil loss. Both erosion control measures reduced soil losses in Tangata, with effectiveness indices ranging from 43 to 100% when compared to the NP plots. RT showed the highest effectiveness, especially in season A. In Murehe, RT minimized runoff and soil losses in both seasons. Yet, the PT were largely inefficient, leading to soil losses exceeding those on the NP plots (ineffectiveness index of -78% and -65% in season A and B, respectively). Though topsoil fertility assessment in the erosion plots showed that the soil quality parameters were significantly higher in RT and NP plots compared to the PT plots on both sites, maize grain yield was not correlated with the physical effectiveness of the erosion control measures. Finally, the effectiveness of soil erosion control measures as well as their positive impacts on soil fertility and production differ not only by terracing type but also by agro-ecological zone and the management or

In Situ analysis of CO2 laser irradiation on controlling progression of erosive lesions on dental enamel.

PubMed

Lepri, Taísa Penazzo; Scatolin, Renata Siqueira; Colucci, Vivian; De Alexandria, Adílis Kalina; Maia, Lucianne Cople; Turssi, Cecília Pedroso; Corona, Silmara Aparecida Milori

2014-08-01

The present study aimed to evaluate in situ the effect of CO2 laser irradiation to control the progression of enamel erosive lesions. Fifty-six slabs of bovine incisors enamel (5 × 3 × 2.5 mm(3) ) were divided in four distinct areas: (1) sound (reference area), (2) initial erosion, (3) treatment (irradiated or nonirradiated with CO2 laser), (4) final erosion (after in situ phase). The initial erosive challenge was performed with 1% citric acid (pH = 2.3), for 5 min, 2×/day, for 2 days. The slabs were divided in two groups according to surface treatment: irradiated with CO2 laser (λ = 10.6 µm; 0.5 W) and nonirradiate. After a 2-day lead-in period, 14 volunteers wore an intraoral palatal appliance containing two slabs (irradiated and nonirradiated), in two intraoral phases of 5 days each. Following a cross-over design during the first intraoral phase, half of the volunteers immersed the appliance in 100 mL of citric acid for 5 min, 3×/day, while other half of the volunteers used deionized water (control). The volunteers were crossed over in the second phase. Enamel wear was determined by an optical 3D profilometer. Three-way ANOVA for repeated measures revealed that there was no significant interaction between erosive challenge and CO2 laser irradiation (P = 0.419). Erosive challenge significantly increased enamel wear (P = 0.001), regardless whether or not CO2 laser irradiation was performed. There was no difference in enamel wear between specimens CO2 -laser irradiated and non-irradiated (P = 0.513). Under intraoral conditions, CO2 laser irradiation did not control the progression of erosive lesions in enamel caused by citric acid. © 2014 Wiley Periodicals, Inc.

[Mechanisms of grass in slope erosion control in Loess sandy soil region of Northwest China].

PubMed

Zhao, Chun-Hong; Gao, Jian-En; Xu, Zhen

2013-01-01

By adopting the method of simulated precipitation and from the viewpoint of slope hydrodynamics, in combining with the analysis of soil resistance to erosion, a quantitative study was made on the mechanisms of grass in controlling the slope erosion in the cross area of wind-water erosion in Loess Plateau of Northwest China under different combinations of rainfall intensity and slope gradient, aimed to provide basis to reveal the mechanisms of vegetation in controlling soil erosion and to select appropriate vegetation for the soil and water conservation in Loess Plateau. The grass Astragalus adsurgens with the coverage about 40% could effectively control the slope erosion. This grass had an efficiency of more than 70% in reducing sediment, and the grass root had a greater effect than grass canopy. On bare slope and on the slopes with the grass plant or only the grass root playing effect, there existed a functional relation between the flow velocity on the slopes and the rainfall intensity and slope gradient (V = DJ(0.33 i 0.5), where V is flow velocity, D is the comprehensive coefficient which varies with different underlying surfaces, i is rainfall intensity, and J is slope gradient). Both the grass root and the grass canopy could markedly decrease the flow velocity on the slopes, and increase the slope resistance, but the effect of grass root in decreasing flow velocity was greater while the effect in increasing resistance was smaller than that of grass canopy. The effect of grass root in increasing slope resistance was mainly achieved by increasing the sediment grain resistance, while the effect of canopy was mainly achieved by increasing the slope form resistance and wave resistance. The evaluation of the soil resistance to erosion by using a conceptual model of sediment generation by overland flow indicated that the critical shear stress value of bare slope and of the slopes with the grass plant or only the grass root playing effect was 0.533, 1.672 and 0

10Be erosion rates controlled by normal fault activity through incision and landslide occurrence

NASA Astrophysics Data System (ADS)

Roda-Boluda, Duna; D'Arcy, Mitch; Whittaker, Alex; Gheorghiu, Delia; Rodes, Angel

2017-04-01

Quantifying erosion rates, and how they compare to rock uplift rates, is fundamental for understanding the evolution of relief and the associated sediment fluxes. The competing effects of rock uplift and erosion are clearly captured by river incision and landsliding, but linking these four important landscape processes remains a major challenge. We address these questions using field data from southern Italy, and quantify the geomorphic response to tectonic forcing. We present 15 new 10Be catchment-averaged erosion rates, collected from catchments along five active normal faults with excellent slip rate constraints. We find that erosion rates are strongly controlled by fault slip rates and that this relationship is mediated by the degree of catchment incision and landslide activity. We find that 10Be samples from low-relief, unincised areas above knickpoints yield consistent erosion rates of ˜ 0.12 mm/yr, while samples collected below knickpoints have erosion rates of ˜ 0.2 - 1.0 mm/yr. This comparison allows us to quantify the impact that transient incisional response has on erosion rates. We demonstrate that in this area incision is associated with frequent, shallow landsliding, and we show that the volumes of landslides stored in the catchments are highly correlated with 10Be-derived sediment flux estimates, suggesting that landslides are likely to be a major contributor to erosional fluxes. Despite widespread landsliding, CRN samples from the studied catchments do provide reliable estimates of catchment-averaged erosion rates, as these are consistent with fault throw patterns and rates. We suggest that this is because landslides are frequent, small and shallow, and are stored on the hillslopes for up to ˜ 103 yrs, representing the integrated record of landsliding over several seismic cycles; and test this hypothesis using a numerical model of landsliding and CRN dynamics. Our results show that adequate CRN mixing can occur through runoff as landslides are

Erosion and Soil Contamination Control Using Coconut Flakes And Plantation Of Centella Asiatica And Chrysopogon Zizanioides

NASA Astrophysics Data System (ADS)

Roslan, Rasyikin; Che Omar, Rohayu; Nor Zuliana Baharuddin, Intan; Zulkarnain, M. S.; Hanafiah, M. I. M.

2016-11-01

Land degradation in Malaysia due to water erosion and water logging cause of loss of organic matter, biodiversity and slope instability but also land are contaminated with heavy metals. Various alternative such as physical remediation are use but it not showing the sustainability in term of environmental sustainable. Due to that, erosion and soil contamination control using coconut flakes and plantation of Centella asiatica and Chrysopogon zizanioides are use as alternative approach for aid of sophisticated green technology known as phytoremediation and mycoremediation. Soil from cabonaceous phyllite located near to Equine Park, Sri Kembangan are use for monitoring the effect of phytoremediation and mycoremediation in reducing soil contamination and biotechnology for erosion control. Five laboratory scale prototypes were designed to monitor the effect of different proportion of coconut flakes i.e. 10%, 25%, 50% & 100% and plantation of Centella asiatica and Chrysopogon zizanioides to reduce the top soil from eroding and reduce the soil contamination. Prototype have been observe started from first week and ends after 12 weeks. Centella asiatica planted on 10% coconut flakes with 90% soil and Chrysopogon zizanioides planted on 25% coconut flakes with 75% soil are selected proportion to be used as phytoremediation and mycoremediation in reducing soil contamination and biotechnology for erosion control.

Extreme soil erosion rates in citrus slope plantations and control strategies. A literature review

NASA Astrophysics Data System (ADS)

Cerdà, Artemi; Ángel González Peñaloza, Félix; Pereira, Paulo; Reyes Ruiz Gallardo, José; García Orenes, Fuensanta; Burguet, María

2013-04-01

irrigated land, and this contributes to increase the soil losses due to the sloping terrain. Although citrus is a world wide food, and occupy a large surface little is being researched on their impact on soil erosion, land degradation and strategies to control the soil, water and nutrient losses. This paper review the research developed until now and the results show that there is a poor background on this topic. It is necessary to develop research projects to improve the knowledge on the impact of citrus plantations on soil degradation and soil erosion. Another key information from the literature review done, is that most of the research was done in two regions of China and one of the Mediterranean. Definitively, a poor understanding of a huge environmental problem that need more scientific research. Acknowledgements The research projects GL2008-02879/BTE and LEDDRA 243857 supported this research. References Bombino, G., Denisi, P., Fortugno, D., Tamburino, V., Zema, D.A., Zimbone, S.M. 2010. Land spreading of solar-dried citrus peel to control runoff and soil erosion. WIT Transactions on Ecology and the Environment, 140, 145-154. Cerdà, A., Giménez Morera, A., Burguet, M., Arcenegui, V., González Peñaloza, F.A., García-Orenes, F., Pereira, P. 2012. The impact of the farming, abandonment and agricultural intensification on loss of water and soil. The example of the northern slopes of the Serra Grossa, Eastern Spain [El impacto del cultivo, el abandono y la intensificación de la agricultura en la pérdida de agua y suelo. el ejemplo de la vertiente norte de la serra grossa en el este peninsular] Cuadernos de Investigacion Geografica, 38 (1), 75-94. Cerdà, A., Jurgensen, M.F. 2008. The influence of ants on soil and water losses from an orange orchard in eastern Spain. Journal of Applied Entomology, 132 (4), 306-314. Cerdà, A., Jurgensen, M.F. 2011. Ant mounds as a source of sediment on citrus orchard plantations in eastern Spain. A three-scale rainfall simulation

Wood strands as an alternative to agricultural straw for erosion control

Treesearch

Randy B. Foltz; James H. Dooley

2004-01-01

Agricultural straw is used in forested areas of the United States for erosion control on burned areas, harvest landings, decommissioned road prisms, road cuts and fills, and other areas of disturbed soil. However, an increased agronomic and ecological value for straw; an increased utilization for energy production, fiber panels, and other higher value uses; a...

Cavitation erosion - scale effect and model investigations

NASA Astrophysics Data System (ADS)

Geiger, F.; Rutschmann, P.

2015-12-01

The experimental works presented in here contribute to the clarification of erosive effects of hydrodynamic cavitation. Comprehensive cavitation erosion test series were conducted for transient cloud cavitation in the shear layer of prismatic bodies. The erosion pattern and erosion rates were determined with a mineral based volume loss technique and with a metal based pit count system competitively. The results clarified the underlying scale effects and revealed a strong non-linear material dependency, which indicated significantly different damage processes for both material types. Furthermore, the size and dynamics of the cavitation clouds have been assessed by optical detection. The fluctuations of the cloud sizes showed a maximum value for those cavitation numbers related to maximum erosive aggressiveness. The finding suggests the suitability of a model approach which relates the erosion process to cavitation cloud dynamics. An enhanced experimental setup is projected to further clarify these issues.

Evaluation of different techniques for erosion control on different roadcuts in its first year of implantation

NASA Astrophysics Data System (ADS)

Gomez, Jose Alfonso; Rodríguez, Abraham; Viedma, Antonio; Contreras, Valentin; Vanwalleghem, Tom; Taguas, Encarnación V.; Giráldez, Juan Vicente

2014-05-01

Linear infrastructures, such as highways and railways, present a large environmental impact. Among this impact is the effect on landscape and the modification of the hydrological conditions of the area and an increase in erosive processes (Martin et al., 2011). The increase of erosive processes is specially significant in roadbanks, resulting in high maintenance costs as well as security risks for the use of the infrastructure if it is not properly controlled. Among roadbanks, roadcuts are specially challenging areas for erosion control and ecological restoration, due to their usually steep slope gradient and poor conditions for establishment of vegetation. There are several studies in Mediterranean conditions indicating how the combination of semiarid conditions with, sporadic, intense rainfall events makes a successful vegetation development and erosion control in motorway roadbanks extremely difficult (e.g. Andrés and Jorbat, 2000; Bochet and García-Fayos, 2004). This communication presents the results of the first year evaluation (hydrological year 2012-2013) of five different erosion control strategies on six different locations under different materials on roadcuts of motorways or railways in Andalusia during 2012-2013 using natural rainfall and simulated rainfall. The six sites were located on roadcuts between 10 and 20 m long on slope steepness ranging from 40 to 90%, in motorways and railways spread over different materials in Andalusia. Site 1, Huelva was located on consolidated sand material, sites 2, Osuna I, site 3, Osuna II and site 4, Mancha Real, on marls. Sites 5, Guadix, and 6, Fiñana, were located on phyllites, in comparison a harder material. At each site 12 plots (10 m long and 2 m wide) were installed using metal sheets buried 10 cm within the soil with their longest side in the direction of the roadcut maximum slope. Six different treatments were evaluated at each site, two replications each. These treatments were: 1- A control with bare

Erosion controls transpressional wedge kinematics

NASA Astrophysics Data System (ADS)

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

Validation of Erosion 3D in Lower Saxony - Comparison between modelled soil erosion events and results of a long term monitoring project

NASA Astrophysics Data System (ADS)

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

Soil erosion in a man-made landscape: the Mediterranean

NASA Astrophysics Data System (ADS)

Cerdà, A.; Ruiz Sinoga, J. D.; Cammeraat, L. H.

2012-04-01

Mediterranean-type ecosystems are characterised by a seasonally contrasted distribution of precipitation, by the coincidence of the driest and hottest season in summer, by an often-mountainous terrain, and by a long history of intense human occupation, especially around the Mediterranean Sea. The history of the Mediterranean lands is the history of human impacts on the soil system, and soil erosion is the most intense and widespread impact on this land where high intensity and uneven rainfall is found. A review of the soil erosion rates measured in the Mediterranean basin will be shown. The measurements done by means of erosion pins, topographical measurements, rainfall simulators, Gerlach collectors in open or close plots, watershed/basin measurements, reservoirs siltation and historical data will be shown. A review of the soil erosion models applied in the Mediterranean will be shown. The tentative approach done until October 2011 show that the soil erosion rates on Mediterranean type ecosystems are not as high as was supposed by the pioneers in the 70's. And this is probably due to the fact that the soils are very shallow and sediments are not available after millennia of high erosion rates. This is related to the large amount of rock fragments are covering the soil, and the rock outcrops that are found in the upper slope trams and the summits. Soil erosion in the Mediterranean is seasonal due to the rainfall concentration in winter, and highly variable within years as the high intensity rainfall events control the sediment production. Natural vegetation is adapted to the Mediterranean environmental conditions, and they are efficient to control the soil losses. An example are the forest fire that increase the soil losses but this is a temporal change as after 2-4 years the soil erosion rates are similar to the pre-fire period. Agriculture lands are the source of sediments although the highest erosion rates are found in badland areas that cover a small part of

Prevention of dentine erosion by brushing with anti-erosive toothpastes.

PubMed

Aykut-Yetkiner, Arzu; Attin, Thomas; Wiegand, Annette

2014-07-01

This in vitro study aimed to investigate the preventive effect of brushing with anti-erosive toothpastes compared to a conventional fluoride toothpaste on dentine erosion. Bovine dentine specimens (n=12 per subgroup) were eroded in an artificial mouth (6 days, 6×30 s/day) using either citric acid (pH:2.5) or a hydrochloric acid/pepsin solution (pH:1.6), simulating extrinsic or intrinsic erosive conditions, respectively. In between, the specimens were rinsed with artificial saliva. Twice daily, the specimens were brushed for 15 s in an automatic brushing machine at 2.5 N with a conventional fluoride toothpaste slurry (elmex, AmF) or toothpaste slurries with anti-erosive formulations: Apacare (NaF/1% nHAP), Biorepair (ZnCO3-HAP), Chitodent (Chitosan), elmex Erosionsschutz (NaF/AmF/SnCl2/Chitosan), mirasensitive hap (NaF/30% HAP), Sensodyne Proschmelz (NaF/KNO3). Unbrushed specimens served as control. Dentine loss was measured profilometrically and statistically analysed using two-way and one-way ANOVA followed by Scheffe's post hoc tests. RDA-values of all toothpastes were determined, and linear mixed models were applied to analyse the influence of toothpaste abrasivity on dentine wear (p<0.05). Dentine erosion of unbrushed specimens amounted to 5.1±1.0 μm (extrinsic conditions) and 12.9±1.4 μm (intrinsic conditions). All toothpastes significantly reduced dentine erosion by 24-67% (extrinsic conditions) and 21-40% (intrinsic conditions). Biorepair was least effective, while all other toothpastes were not significantly different from each other. Linear mixed models did not show a significant effect of the RDA-value of the respective toothpaste on dentine loss. Toothpastes with anti-erosive formulations reduced dentine erosion, especially under simulated extrinsic erosive conditions, but were not superior to a conventional fluoride toothpaste. Copyright © 2014 Elsevier Ltd. All rights reserved.

The Streambank Erosion Control Evaluation and Demonstration Act of 1974, Section 32, Public Law 93-251. Appendix F. Yazoo River Basin Demonstration Projects.

DTIC Science & Technology

1981-12-01

function enhanced navigation on many of the basins streams. The system also served as a tributary for local runoff . This relationship was permanently...and should be divided into geologic sequences and time periods. The geologic controls in a -. basin denote the type of erosion, thus the runoff and...should not be used for comparison with stages or discharges associated with earlier runoff events because the stage discharge relations were altered by the

The Effectiveness of Aerial Hydromulch as a Post-Fire Erosion Control Treatment in Southern California

Treesearch

P.M. Wohlgemuth; J.L. Beyers; P.R. Robichaud

2010-01-01

Following a wildfire in the Santa Ana Mountains of northeast Orange County, California, a monitoring project was established to test whether aerial hydromulch reduced post-fire hillslope and small watershed erosion, and to document its impact on re-growing vegetation. The study site received below normal rainfall both the first and second winters after the fire. A high...

Validating and Improving Interrill Erosion Equations

PubMed Central

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

Towards estimates of future rainfall erosivity in Europe based on REDES and WorldClim datasets

NASA Astrophysics Data System (ADS)

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

2017-05-01

The policy requests to develop trends in soil erosion changes can be responded developing modelling scenarios of the two most dynamic factors in soil erosion, i.e. rainfall erosivity and land cover change. The recently developed Rainfall Erosivity Database at European Scale (REDES) and a statistical approach used to spatially interpolate rainfall erosivity data have the potential to become useful knowledge to predict future rainfall erosivity based on climate scenarios. The use of a thorough statistical modelling approach (Gaussian Process Regression), with the selection of the most appropriate covariates (monthly precipitation, temperature datasets and bioclimatic layers), allowed to predict the rainfall erosivity based on climate change scenarios. The mean rainfall erosivity for the European Union and Switzerland is projected to be 857 MJ mm ha-1 h-1 yr-1 till 2050 showing a relative increase of 18% compared to baseline data (2010). The changes are heterogeneous in the European continent depending on the future projections of most erosive months (hot period: April-September). The output results report a pan-European projection of future rainfall erosivity taking into account the uncertainties of the climatic models.

Towards estimates of future rainfall erosivity in Europe based on REDES and WorldClim datasets.

PubMed

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

2017-05-01

The policy requests to develop trends in soil erosion changes can be responded developing modelling scenarios of the two most dynamic factors in soil erosion, i.e. rainfall erosivity and land cover change. The recently developed Rainfall Erosivity Database at European Scale (REDES) and a statistical approach used to spatially interpolate rainfall erosivity data have the potential to become useful knowledge to predict future rainfall erosivity based on climate scenarios. The use of a thorough statistical modelling approach (Gaussian Process Regression), with the selection of the most appropriate covariates (monthly precipitation, temperature datasets and bioclimatic layers), allowed to predict the rainfall erosivity based on climate change scenarios. The mean rainfall erosivity for the European Union and Switzerland is projected to be 857 MJ mm ha -1  h -1  yr -1 till 2050 showing a relative increase of 18% compared to baseline data (2010). The changes are heterogeneous in the European continent depending on the future projections of most erosive months (hot period: April-September). The output results report a pan-European projection of future rainfall erosivity taking into account the uncertainties of the climatic models.

A probabilistic approach to modeling erosion for spatially-varied conditions

Treesearch

William J. Elliot; Peter R. Robichaud; C. D. Pannkuk

2001-01-01

In the years following a major forest disturbance, such as fire, the erosion rate is greatly influenced by variability in weather, in soil properties, and in spatial distribution. This paper presents a method to incorporate these variabilities into the erosion rate predicted by the Water Erosion Prediction Project model. It appears that it is not necessary to describe...

Study on the water resources optimal operation based on riverbed wind erosion control in West Liaohe River plain

NASA Astrophysics Data System (ADS)

Wanguang, Sun; Chengzhen, Li; Baoshan, Fan

2018-06-01

Rivers are drying up most frequently in West Liaohe River plain and the bare river beds present fine sand belts on land. These sand belts, which yield a dust heavily in windy days, stress the local environment deeply as the riverbeds are eroded by wind. The optimal operation of water resources, thus, is one of the most important methods for preventing the wind erosion of riverbeds. In this paper, optimal operation model for water resources based on riverbed wind erosion control has been established, which contains objective function, constraints, and solution method. The objective function considers factors which include water volume diverted into reservoirs, river length and lower threshold of flow rate, etc. On the basis of ensuring the water requirement of each reservoir, the destruction of the vegetation in the riverbed by the frequent river flow is avoided. The multi core parallel solving method for optimal water resources operation in the West Liaohe River Plain is proposed, which the optimal solution is found by DPSA method under the POA framework and the parallel computing program is designed in Fork/Join mode. Based on the optimal operation results, the basic rules of water resources operation in the West Liaohe River Plain are summarized. Calculation results show that, on the basis of meeting the requirement of water volume of every reservoir, the frequency of reach river flow which from Taihekou to Talagan Water Diversion Project in the Xinkai River is reduced effectively. The speedup and parallel efficiency of parallel algorithm are 1.51 and 0.76 respectively, and the computing time is significantly decreased. The research results show in this paper can provide technical support for the prevention and control of riverbed wind erosion in the West Liaohe River plain.

Tectonic control of erosion in the southern Central Andes

NASA Astrophysics Data System (ADS)

Val, Pedro; Venerdini, Agostina L.; Ouimet, William; Alvarado, Patricia; Hoke, Gregory D.

2018-01-01

Landscape evolution modeling and global compilations of exhumation data indicate that a wetter climate, mainly through orographic rainfall, can govern the spatial distribution of erosion rates and crustal strain across an orogenic wedge. However, detecting this link is not straightforward since these relationships can be modulated by tectonic forcing and/or obscured by heavy-tailed frequencies of catchment discharge. This study combines new and published along-strike average rates of catchment erosion constrained by 10Be and river-gauge data in the Central Andes between 28°S and 36°S. These data reveal a nearly identical latitudinal pattern in erosion rates on both sides of the range, reaching a maximum of 0.27 mm/a near 34°S. Collectively, data on topographic and fluvial relief, variability of rainfall and discharge, and crustal seismicity suggest that the along-strike pattern of erosion rates in the southern Central Andes is largely independent of climate, but closely relates to the N-S distribution of shallow crustal seismicity and diachronous surface uplift. The consistently high erosion rates on either side of the orogen near 34°S imply that climate plays a secondary role in the mass flux through an orogenic wedge where the perturbation to base level is similar on both sides.

Streambank Protection and Erosion Control.

DTIC Science & Technology

1987-01-01

TABLE OF CONTENTS N CHAPTER ONE - INTRODUCTION ----------------------------------------- -- 1. 1.1 Purpose...downstream cross sectional area by stream bank erosion and bed scour to accommodate the increased flow. This may be caused by poor planning and assessment...the magnitude, except for very large floods which occur infrequently. 3.2 Channel Geometry [6] .*. Channel geometry of a river cross section is an

Optimal land use management for soil erosion control by using an interval-parameter fuzzy two-stage stochastic programming approach.

PubMed

Han, Jing-Cheng; Huang, Guo-He; Zhang, Hua; Li, Zhong

2013-09-01

Soil erosion is one of the most serious environmental and public health problems, and such land degradation can be effectively mitigated through performing land use transitions across a watershed. Optimal land use management can thus provide a way to reduce soil erosion while achieving the maximum net benefit. However, optimized land use allocation schemes are not always successful since uncertainties pertaining to soil erosion control are not well presented. This study applied an interval-parameter fuzzy two-stage stochastic programming approach to generate optimal land use planning strategies for soil erosion control based on an inexact optimization framework, in which various uncertainties were reflected. The modeling approach can incorporate predefined soil erosion control policies, and address inherent system uncertainties expressed as discrete intervals, fuzzy sets, and probability distributions. The developed model was demonstrated through a case study in the Xiangxi River watershed, China's Three Gorges Reservoir region. Land use transformations were employed as decision variables, and based on these, the land use change dynamics were yielded for a 15-year planning horizon. Finally, the maximum net economic benefit with an interval value of [1.197, 6.311] × 10(9) $ was obtained as well as corresponding land use allocations in the three planning periods. Also, the resulting soil erosion amount was found to be decreased and controlled at a tolerable level over the watershed. Thus, results confirm that the developed model is a useful tool for implementing land use management as not only does it allow local decision makers to optimize land use allocation, but can also help to answer how to accomplish land use changes.

Optimal Land Use Management for Soil Erosion Control by Using an Interval-Parameter Fuzzy Two-Stage Stochastic Programming Approach

NASA Astrophysics Data System (ADS)

Han, Jing-Cheng; Huang, Guo-He; Zhang, Hua; Li, Zhong

2013-09-01

Soil erosion is one of the most serious environmental and public health problems, and such land degradation can be effectively mitigated through performing land use transitions across a watershed. Optimal land use management can thus provide a way to reduce soil erosion while achieving the maximum net benefit. However, optimized land use allocation schemes are not always successful since uncertainties pertaining to soil erosion control are not well presented. This study applied an interval-parameter fuzzy two-stage stochastic programming approach to generate optimal land use planning strategies for soil erosion control based on an inexact optimization framework, in which various uncertainties were reflected. The modeling approach can incorporate predefined soil erosion control policies, and address inherent system uncertainties expressed as discrete intervals, fuzzy sets, and probability distributions. The developed model was demonstrated through a case study in the Xiangxi River watershed, China's Three Gorges Reservoir region. Land use transformations were employed as decision variables, and based on these, the land use change dynamics were yielded for a 15-year planning horizon. Finally, the maximum net economic benefit with an interval value of [1.197, 6.311] × 109 was obtained as well as corresponding land use allocations in the three planning periods. Also, the resulting soil erosion amount was found to be decreased and controlled at a tolerable level over the watershed. Thus, results confirm that the developed model is a useful tool for implementing land use management as not only does it allow local decision makers to optimize land use allocation, but can also help to answer how to accomplish land use changes.

Event-based design tool for construction site erosion and sediment controls

NASA Astrophysics Data System (ADS)

Trenouth, William R.; Gharabaghi, Bahram

2015-09-01

This paper provides additional discussion surrounding the novel event-based soil loss models developed by Trenouth and Gharabaghi (2015) for the design of erosion and sediment controls (ESCs) for various phases of construction - from pre-development to post-development conditions. The datasets for the study were obtained from three Ontario sites - Greensborough, Cookstown, and Alcona - in addition to datasets mined from the literature for three additional sites - Treynor, Iowa, Coshocton, Ohio and Cordoba, Spain. Model performances were evaluated for each of the study sites, and quantified using commonly-reported statistics. This work is nested within a broader conceptual framework, which includes the estimation of ambient receiving water quality, the prediction of event mean runoff quality for a given design storm, and the calculation of the required level of protection using adequate ESCs to meet receiving water quality guidelines. These models allow design engineers and regulatory agencies to assess the potential risk of ecological damage to receiving waters due to inadequate soil erosion and sediment control practices using dynamic scenario forecasting when considering rapidly changing land use conditions during various phases of construction, typically for a 2- or 5-year design storm return period.

Comprehensive Erosion and Sediment Control Training Program for Job Superintendents and Inspectors.

ERIC Educational Resources Information Center

Porter, Harry L., Jr.

One of two training program texts built around the Virginia Erosion and Sediment Control Law and Program, this guide presents a program designed to meet the needs of job superintendents and inspectors. (The other guide, containing a program for engineers, architects, and planners, was designed to train professional people who need engineering and…

Investigation of erosion rates of field samples using FDOT's enhanced sediment erosion rate flume (SERF).

DOT National Transportation Integrated Search

2013-09-01

The first part of this project was to enhance and improve the Florida Department of Transportations : Sediment Erosion Rate Flume (SERF) device. Notable improvements include a pump repair, laser : system enhancement, installation of a digital vide...

Modeling erosion on steep sagebrush rangeland before and after prescribed fire

Treesearch

Corey A. Moffet; Frederick B. Pierson; Kenneth E. Spaeth

2007-01-01

Fire in sagebrush rangelands significantly alters canopy cover, ground cover, and soil properties that influence runoff and erosion processes. Runoff is generated more quickly and a larger volume of runoff is produced following prescribed fire. The result is increased risk of severe erosion and downstream flooding. The Water Erosion Prediction Project (WEPP), developed...

The age of vines as a controlling factor of soil erosion processes in Mediterranean vineyards.

PubMed

Rodrigo-Comino, Jesús; Brevik, Eric C; Cerdà, Artemi

2018-03-01

Vineyards incur the highest soil and water losses among all Mediterranean agricultural fields. The state-of-the-art shows that soil erosion in vineyards has been primarily surveyed with topographical methods, soil erosion plots and rainfall simulations, but these techniques do not typically assess temporal changes in soil erosion. When vines are planted they are about 30cm high×1cm diameter without leaves, the root system varies from 2 to over 40cm depth, and sometimes the lack of care used during transplanting can result in a field with highly erodible bare soils. This means that the time since vine plantation plays a key role in soil erosion rates, but very little attention has been paid to this by the scientific community. Thus, the main goal of this research was to estimate soil losses and assess soil erosion processes in two paired vineyard plantations of different ages. To achieve this goal, the improved stock unearthing method (ISUM) was applied to vineyards on colluvial parent materials with similar soil properties, topographical characteristics and land managements in the Les Alcusses Valley, southwestern Valencia province, Spain. Our findings suggested that the old vineyards showed lower erosion rates (-1.61Mgha -1 yr -1 ) than those that were recently planted (-8.16Mgha -1 yr -1 ). This is because of the damage that the plantation of the vines causes to soil. Tillage after planting (4 times per year) resulted in changes in the inter-row and row morphology, promoting the development of a ridge underneath the vines that disconnected the inter-rows and reduced soil losses with time. After the second year and until the 25th year after plantation, soil erosion was approximately 1Mgha -1 y -1 , which means that most of the erosion took place during the first two years after the plantation. Soil conservation strategies should be applied immediately after the plantation works to allow sustainable grape production. That is when soil erosion most needs to be

Monthly Rainfall Erosivity Assessment for Switzerland

NASA Astrophysics Data System (ADS)

Schmidt, Simon; Meusburger, Katrin; Alewell, Christine

2016-04-01

Water erosion is crucially controlled by rainfall erosivity, which is quantified out of the kinetic energy of raindrop impact and associated surface runoff. Rainfall erosivity is often expressed as the R-factor in soil erosion risk models like the Universal Soil Loss Equation (USLE) and its revised version (RUSLE). Just like precipitation, the rainfall erosivity of Switzerland has a characteristic seasonal dynamic throughout the year. This inter-annual variability is to be assessed by a monthly and seasonal modelling approach. We used a network of 86 precipitation gauging stations with a 10-minute temporal resolution to calculate long-term average monthly R-factors. Stepwise regression and Monte Carlo Cross Validation (MCCV) was used to select spatial covariates to explain the spatial pattern of R-factor for each month across Switzerland. The regionalized monthly R-factor is mapped by its individual regression equation and the ordinary kriging interpolation of its residuals (Regression-Kriging). As covariates, a variety of precipitation indicator data has been included like snow height, a combination of hourly gauging measurements and radar observations (CombiPrecip), mean monthly alpine precipitation (EURO4M-APGD) and monthly precipitation sums (Rhires). Topographic parameters were also significant explanatory variables for single months. The comparison of all 12 monthly rainfall erosivity maps showed seasonality with highest rainfall erosivity in summer (June, July, and August) and lowest rainfall erosivity in winter months. Besides the inter-annual temporal regime, a seasonal spatial variability was detectable. Spatial maps of monthly rainfall erosivity are presented for the first time for Switzerland. The assessment of the spatial and temporal dynamic behaviour of the R-factor is valuable for the identification of more susceptible seasons and regions as well as for the application of selective erosion control measures. A combination with monthly vegetation

Using computer models to design gully erosion control structures for humid northern Ethiopia

USDA-ARS?s Scientific Manuscript database

Classic gully erosion control measures such as check dams have been unsuccessful in halting gully formation and growth in the humid northern Ethiopian highlands. Gullies are typically formed in vertisols and flow often bypasses the check dams as elevated groundwater tables make gully banks unstable....

Performance and efficiency of geotextile-supported erosion control measures during simulated rainfall events

NASA Astrophysics Data System (ADS)

Obriejetan, Michael; Rauch, Hans Peter; Florineth, Florin

2013-04-01

Erosion control systems consisting of technical and biological components are widely accepted and proven to work well if installed properly with regard to site-specific parameters. A wide range of implementation measures for this specific protection purpose is existent and new, in particular technical solutions are constantly introduced into the market. Nevertheless, especially vegetation aspects of erosion control measures are frequently disregarded and should be considered enhanced against the backdrop of the development and realization of adaptation strategies in an altering environment due to climate change associated effects. Technical auxiliaries such as geotextiles typically used for slope protection (nettings, blankets, turf reinforcement mats etc.) address specific features and due to structural and material diversity, differing effects on sediment yield, surface runoff and vegetational development seem evident. Nevertheless there is a knowledge gap concerning the mutual interaction processes between technical and biological components respectively specific comparable data on erosion-reducing effects of technical-biological erosion protection systems are insufficient. In this context, an experimental arrangement was set up to study the correlated influences of geotextiles and vegetation and determine its (combined) effects on surface runoff and soil loss during simulated heavy rainfall events. Sowing vessels serve as testing facilities which are filled with top soil under application of various organic and synthetic geotextiles and by using a reliable drought resistant seed mixture. Regular vegetational monitoring as well as two rainfall simulation runs with four repetitions of each variant were conducted. Therefore a portable rainfall simulator with standardized rainfall intensity of 240 mm h-1 and three minute rainfall duration was used to stress these systems on different stages of plant development at an inclination of 30 degrees. First results show

Interventions for recurrent corneal erosions.

PubMed

Watson, Stephanie L; Lee, Ming-Han H; Barker, Nigel H

2012-09-12

Recurrent corneal erosion is a common cause of disabling ocular symptoms and predisposes the cornea to infection. It may follow corneal trauma. Measures to prevent the development of recurrent corneal erosion following corneal trauma have not been firmly established. Once recurrent corneal erosion develops simple medical therapy (standard treatment) may lead to resolution of the episode. However, some patients continue to suffer when such therapy fails and once resolved further episodes of recurrent erosion may occur. A number of treatment and prophylactic options are then available but there is no agreement as to the best option. To assess the effectiveness and safety of prophylactic and treatment regimens for recurrent corneal erosion. We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2012, Issue 6), MEDLINE (January 1946 to June 2012), EMBASE (January 1980 to June 2012), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to June 2012), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 13 June 2012. We also contacted researchers in the field. We included randomised and quasi-randomised trials that compared a prophylactic or treatment regimen with another prophylaxis/treatment or no prophylaxis/treatment for patients with recurrent corneal erosion. Two authors independently extracted data and assessed trial quality. We contacted study authors for additional information. Seven randomised and one quasi-randomised controlled trial were included in the review. The trials were heterogenous and of poor quality. Safety data presented were incomplete. For the treatment of recurrent

Controlling erosion along highways with vegetation or other protective cover.

DOT National Transportation Integrated Search

1976-01-01

Construction operations in highway corridors disturb the natural vegetation and land contours causing potential erosion sites if left denuded. Minimizing erosion on these areas is based on the principles of maximizing water infiltration and reducing ...

Hydrological and sedimentary controls over fluvial thermal erosion, the Lena River, central Yakutia

NASA Astrophysics Data System (ADS)

Tananaev, Nikita I.

2016-01-01

Water regime and sedimentary features of the middle Lena River reach near Yakutsk, central Yakutia, were studied to assess their control over fluvial thermal erosion. The Lena River floodplain in the studied reach has complex structure and embodies multiple levels varying in height and origin. Two key sites, corresponding to high and medium floodplain levels, were surveyed in 2008 to describe major sedimentary units and properties of bank material. Three units are present in both profiles, corresponding to topsoil, overbank (cohesive), and channel fill (noncohesive) deposits. Thermoerosional activity is mostly confined to a basal layer of frozen channel fill deposits and in general occurs within a certain water level interval. Magnitude-frequency analysis of water level data from Tabaga gauging station shows that a single interval can be deemed responsible for the initiation of thermal action and development of thermoerosional notches. This interval corresponds to the discharges between 21,000 and 31,000 m3 s- 1, observed normally during spring meltwater peak and summer floods. Competence of fluvial thermal erosion depends on the height of floodplain level being eroded, as it acts preferentially in high floodplain banks. In medium floodplain banks, thermal erosion during spring flood is constrained by insufficient bank height, and erosion is essentially mechanical during summer flood season. Bank retreat rate is argued to be positively linked with bank height under periglacial conditions.

Comprehensive Erosion and Sediment Control Training Program for Engineers, Architects and Planners.

ERIC Educational Resources Information Center

Porter, Harry L., Jr.

This program training text was designed to provide uniform instruction to the engineer, architect, planner, and others who will be helping to implement an erosion and sediment control program. Although tailored for use in Virginia, the basic principles covered are universal, and the material is adaptable to meet the needs in any State. The 11…

Low cost forged Y-pattern valves control hot corrosive/erosive gases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gaines, A.

The Morgantown Energy Technology Center in Morgantown, West Virginia is a research facility of the US Department of Energy (DOE) that does research on fossil fuels utilization and conversion to provide improved and environmentally acceptable energy sources. One area of investigation in the Morgantown facility is the use of gaseous fuels derived from coal from fluidized-bed and fixed-bed gasification technologies. The corrosive and slightly erosive gases and vapors at about 1000F and from 100 to 300 psi are treated in an experimental desulfurization unit to produce fuel gas with greatly enhanced environmental characteristics. The valves in use were constructed ofmore » Type 347 stainless steel, a stabilized version of 316 SS, and cost about $6000 for the 2'' size and about $4000 for the 1'' size. Despite the high cost, the valve sometimes became difficult or impossible to operate due to metal failures. The Technology Center had a number of new Class 1500 Y-pattern (angle-style) globe valves in inventory. The control valve body and bonnet are forged chrome moly steel (ASTM-H182-F22), the stem assembly is a 13% chrome alloy with an erosion resistant hard faced disc, and the seat ring is a cobalt-base alloy fused in place as an integral part of the body. Stem packing as an either wire inserted molded asbestos or Grafoil flexible graphite. The Y-pattern globe valves in 1 and 2'' sizes, which were judged potentially suitable and on hand, were installed in the experimental desulfization unit as well as in the connecting hot gas piping system to a new coal gasification process. The Class 1500 Y-pattern valves have provided reliable control of the hot corrosive and erosive gas streams with very little maintenance.« less

Shoreline Erosion and Proposed Control at Experimental Facility 15-Spesutie Island

DTIC Science & Technology

2017-09-01

Island, it is made up of various facilities and ranges designed for weapons testing as well as automotive testing . These ranges belong to the...ARL-SR-0383 ● SEP 2017 US Army Research Laboratory Shoreline Erosion and Proposed Control at Experimental Facility 15–Spesutie...in this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents. Citation

7 CFR 3201.68 - Erosion control materials.

Code of Federal Regulations, 2014 CFR

2014-01-01

... MANAGEMENT, DEPARTMENT OF AGRICULTURE GUIDELINES FOR DESIGNATING BIOBASED PRODUCTS FOR FEDERAL PROCUREMENT... manufactured for use on construction, demolition, or other sites to prevent wind or water erosion of loose...

7 CFR 3201.68 - Erosion control materials.

Code of Federal Regulations, 2013 CFR

2013-01-01

... MANAGEMENT, DEPARTMENT OF AGRICULTURE GUIDELINES FOR DESIGNATING BIOBASED PRODUCTS FOR FEDERAL PROCUREMENT... manufactured for use on construction, demolition, or other sites to prevent wind or water erosion of loose...

7 CFR 3201.68 - Erosion control materials.

Code of Federal Regulations, 2012 CFR

2012-01-01

... MANAGEMENT, DEPARTMENT OF AGRICULTURE GUIDELINES FOR DESIGNATING BIOBASED PRODUCTS FOR FEDERAL PROCUREMENT... manufactured for use on construction, demolition, or other sites to prevent wind or water erosion of loose...

Micro-topographic controls on hillslope erosion and deposition: a multi-scale case study using random forest

NASA Astrophysics Data System (ADS)

Lu, X.; Li, Y.; Washington-Allen, R. A.; Li, Y.

2017-12-01

Topography imposes a significant impact on water induced soil erosion and deposition. Although existing models incorporate topographic factors in the prediction of erosion, the topography of the hillslope is often considered as a whole and summarized as a single value, without accounting for the micro-variations within the hillslope created through factors including local roughness and channelization. Within-hillslope scale erosion and deposition and their micro-topographic controls are not well understood due to a lack of means to monitor and quantify the geomorphic change with high resolution and accuracy. Advances in remote sensing technology enabled mapping and quantification of erosion and deposition at such scale. On a hillslope in Loudoun Tennessee USA, we used laser scanning to produce temporal DEMs, based on which the erosion and deposition were calculated, and topographic factors including slope, aspect, roughness index, convergence index, terrain wetness index, channel depth, contributing area, and slope length-gradient were derived. To examine how these micro-topographic factors affect erosion and deposition, random forest regression models were used for erosion and deposition at two scales: analytical windows and rill basins (RBs). Two variables representing the impact of precipitation and freeze/thaw are also incorporated. Our models show that the influences of topographic variables on erosion and deposition differ regarding different analytical scales. The two variables denoting the relative location within a slope (elevation) and the RBs (contributing area) are the most important. Threshold effects show that the locations at low elevations are more subjective to more erosion and also more deposition, suggesting larger contributing areas lead to more dynamics regarding sediment exchange. The relative location along rill cross-sections (channel depth) is also important, especially for deposition. Thresholds show that along the cross-sections, erosion

Costs and benefits of urban erosion and sediment control: The North Carolina experience

NASA Astrophysics Data System (ADS)

Paterson, Robert G.; Luger, Michael I.; Burby, Raymond J.; Kaiser, Edward J.; Malcom, H. Rooney; Beard, Alicia C.

1993-03-01

The EPA’s new nonpoint source pollution control requirements will soon institutionalize urban erosion and sediment pollution control practices nationwide. The public and private sector costs and social benefits associated with North Carolina’s program (one of the strongest programs in the country in terms of implementation authority, staffing levels, and comprehensiveness of coverage) are examined to provide general policy guidance on questions relating to the likely burden the new best management practices will have on the development industry, the likely costs and benefits of such a program, and the feasibility of running a program on a cost recovery basis. We found that urban erosion and sediment control requirements were not particularly burdensome to the development industry (adding about 4% on average to development costs). Public-sector program costs ranged between 2.4 and 4.8 million in fiscal year 1989. Our contingent valuation survey suggests that urban households in North Carolina are willing to pay somewhere between 7.1 and 14.2 million a year to maintain current levels of sediment pollution control. Our benefit-cost analysis suggests that the overall ratio is likely to be positive, although a definitive figure is elusive. Lastly, we found that several North Carolina localities have cost recovery fee systems that are at least partially self-financing.

Modeling erosion under future climates with the WEPP model

Treesearch

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...

Efficiency of erosion control practices of the Virginia Department of Highways and Transportation : final report.

DOT National Transportation Integrated Search

1982-01-01

Twelve streams affected by highway construction were monitored to ascertain the effectiveness of the Virginia Department of Highways and Transportation's erosion and sediment control practices. The streams were located throughout Virginia in areas ha...

Bed erosion control at 60 degree river confluence using vanes

NASA Astrophysics Data System (ADS)

Wuppukondur, Ananth; Chandra, Venu

2017-04-01

Confluences are common occurrences along natural rivers. Hydrodynamics at the confluence is complex due to merging of main and lateral flows with different characteristics. Bed erosion occurs at the confluence due to turbulence and also secondary circulation induced by centrifugal action of the lateral flow. The eroded sediment poses various problems in the river ecosystem including river bank failure. Reservoirs are majorly affected due to sediment deposition which reduces storage capacity. The bed erosion also endangers stability of pipeline crossings and bridge piers. The aim of this experimental study is to check the performance of vanes in controlling bed erosion at the confluence. Experiments are performed in a 600 confluence mobile bed model with a non-uniform sediment of mean particle size d50 = 0.28mm. Discharge ratio (q=ratio of lateral flow discharge to main flow discharge) is maintained as 0.5 and 0.75 with a constant average main flow depth (h) of 5cm. Vanes of width 0.3h (1.5cm) and thickness of 1 mm are placed along the mixing layer at an angle of 150, 300 and 600(with respect to main flow) to perform the experiments. Also, two different spacing of 2h and 3h (10cm and 15cm) between the vanes are used for conducting the experiments. A digital point gauge with an accuracy of ±0.1mm is used to measure bed levels and flow depths at the confluence. An Acoustic Doppler Velocitimeter (ADV) with a frequency of 25Hz and accuracy of ±1mm/s is used to measure flow velocities. Maximum scour depth ratio Rmax, which is ratio between maximum scour depth (Ds) and flow depth (h), is used to present the experimental results.From the experiments without vanes, it is observed that the velocities are increasing along the mixing layer and Rmax=0.82 and 1.06, for q=0.5 and 0.75, respectively. The velocities reduce with vanes since roughness increases along the mixing layer. For q=0.5 and 0.75, Rmax reduces to 0.62 and 0.7 with vanes at 2h spacing, respectively. Similarly

The contribution of mulches to control high soil erosion rates in vineyards in Eastern Spain

NASA Astrophysics Data System (ADS)

Cerdà, Artemi; Jordán, Antonio; Zavala, Lorena; José Marqués, María; Novara, Agata

2014-05-01

Soil erosion take place in degraded ecosystem where the lack of vegetation, drought, erodible parent material and deforestation take place (Borelli et al., 2013; Haregeweyn et al., 2013; Zhao et al., 2013). Agriculture management developed new landscapes (Ore and Bruins, 2012) and use to trigger non-sustainable soil erosion rates (Zema et al., 2012). High erosion rates were measured in agriculture land (Cerdà et al., 2009), but it is also possible to develop managements that will control the soil and water losses, such as organic amendments (Marqués et al., 2005), plant cover (Marqués et al., 2007) and geotextiles (Giménez Morera et al., 2010). The most successful management to restore the structural stability and the biological activity of the agriculture soil has been the organic mulches (García Orenes et al; 2009; 2010; 2012). The straw mulch is also very successful on bare fire affected soil (Robichaud et al., 2013a; 2013b), which also contributes to a more stable soil moisture content (García-Moreno et al., 2013). The objective of this research is to determine the impact of two mulches: wheat straw and chipped branches, on the soil erosion rates in a rainfed vineyard in Eastern Spain. The research site is located in the Les Alcusses Valley within the Moixent municipality. The Mean annual temperature is 13 ºC, and the mean annual rainfall 455 mm. Soil are sandy loam, and are developed at the foot-slope of a Cretaceous limestone range, the Serra Grossa range. The soils use to be ploughed and the features of soil erosion are found after each thunderstorm. Rills are removed by ploughing. Thirty rainfall simulation experiments were carried out in summer 2011 during the summer drought period. The simulated rainfall lasted during 1 hour at a 45 mmh-1 intensity on 1 m2 plots (Cerdà and Doerr, 2010; Cerdà and Jurgensen 2011). Ten experiments were carried out on the control plots (ploughed), 10 on straw mulch covered plots, and 10 on chipped branches covered

Immunohistochemical Study of p53 Expression in Patients with Erosive and Non-Erosive Oral Lichen Planus

PubMed Central

Shiva, Atena; Zamanian, Ali; Arab, Shahin; Boloki, Mahsa

2018-01-01

Statement of the Problem: Oral lichen planus is a common mucocutaneous lesion with a chronic inflammatory process mediated by immune factors while a few cases of the disease become malignant. Purpose: This study aimed to determine the frequency of p53 marker as a tumor suppressor in patients with erosive and non-erosive oral lichen planus (OLP) by using immunohistochemical methods. Materials and Method: This descriptive cross-sectional study investigated the p53 expression in 16 erosive OLP, 16 non-erosive OLP samples, and 8 samples of normal oral mucosa through immunohistochemistry. The percentage of stained cells in basal and suprabasal layers, and inflammatory infiltrate were graded according to the degree of staining; if 0%, <10%, 10-25%, and >50% of the cells were stained, they were considered as (-), (+), (++), (+++) and (++++), respectively. The obtained data was statistically analyzed and compared by using Chi square and Fisher’s exact test. Results: The mean percentage of p53 positive cells in erosive OLP (34.5±14.2) was considerably higher than that in non-erosive OLP (23.8±10.4) and normal mucosa (17.5±17). There was a significant difference among the three groups of erosive, non-erosive and control in terms of staining intensity. No significant difference existed between the patients’ age and sex in the two OLP groups. Conclusion: The increased incidence of p53 from normal mucosa to erosive OLP indicated the difference between biological behavior of erosive and non-erosive OLP. It can be claimed that the erosive OLP has great premalignant potential compared with the non-erosive one.

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

USGS Publications Warehouse

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

Materials erosion and redeposition studies at the PISCES-facility: net erosion under redeposition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hirooka, Y.; Goebel, D.M.; Conn, R.W.

1986-05-01

Simultaneous erosion and redeposition of copper and 304 stainless steel under controlled and continuous plasma (D,He,Ar) bombardment has been investigated in the PISCES-facility, which generates typical edge-plasma conditions of magnetic fusion devices. The plasma bombardment conditions are: incident ion flux in the range from 10/sup 17/ to 10/sup 18/ ions/sec/cm/sup 2/, ion bombarding energy of 100 eV, electron temperature in the range from 5 to 15 eV, plasma density in the range from 10/sup 11/ to 10/sup 13/ cm/sup -3/, target temperature in the range from 300 to 900K, and the total ion fluence in the range from 10/sup 20/more » to 10/sup 22/ ions/cm/sup 2/. The net erosion yield under redeposition is found to be significantly smaller than the classical sputtering yield data. A first-order modeling is attempted to interpret the erosion and redeposition behavior of materials under plasma bombardment. It is pointed out both theoretically and experimentally that the mean free path for electron impact ionization of the sputtered material is the key parameter to control the overall mechanism of erosion and redeposition. Strongly modified surface morphologies of bombarded targets are observed and indicate a retrapping effect.« less

Can warmwater streams be rehabilitated using watershed-scale standard erosion control measures alone?

PubMed

Shields, F Douglas; Knight, Scott S; Cooper, Charles M

2007-07-01

Degradation of warmwater streams in agricultural landscapes is a pervasive problem, and reports of restoration effectiveness based on monitoring data are rare. Described is the outcome of rehabilitation of two deeply incised, unstable sand-and-gravel-bed streams. Channel networks of both watersheds were treated using standard erosion control measures, and aquatic habitats within 1-km-long reaches of each stream were further treated by addition of instream structures and planting woody vegetation on banks ("habitat rehabilitation"). Fish and their habitats were sampled semiannually during 1-2 years before rehabilitation, 3-4 years after rehabilitation, and 10-11 years after rehabilitation. Reaches with only erosion control measures located upstream from the habitat measure reaches and in similar streams in adjacent watersheds were sampled concurrently. Sediment concentrations declined steeply throughout both watersheds, with means > or = 40% lower during the post-rehabilitation period than before. Physical effects of habitat rehabilitation were persistent through time, with pool habitat availability much higher in rehabilitated reaches than elsewhere. Fish community structure responded with major shifts in relative species abundance: as pool habitats increased after rehabilitation, small-bodied generalists and opportunists declined as certain piscivores and larger-bodied species such as centrarchids and catostomids increased. Reaches without habitat rehabilitation were significantly shallower, and fish populations there were similar to the rehabilitated reaches prior to treatment. These findings are applicable to incised, warmwater streams draining agricultural watersheds similar to those we studied. Rehabilitation of warmwater stream ecosystems is possible with current knowledge, but a major shift in stream corridor management strategies will be needed to reverse ongoing degradation trends. Apparently, conventional channel erosion controls without instream habitat

Climate change impacts on soil erosion in the Great Lakes Region

USDA-ARS?s Scientific Manuscript database

Quantifying changes in potential soil erosion under projections of changing climate is important for the sustainable management of land resources, especially for regions dominated by agricultural land use, as soil loss estimates will be helpful in identifying areas susceptible to erosion, targeting ...

Erosion-Resistant Nanocoatings for Improved Energy Efficiency in Gas Turbines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alman, David; Marcio, Duffles

2014-02-05

The objective of this Stage Gate IV project was to test and substantiate the viability of an erosion-resistant nanocoating for application on compressor airfoils for gas turbines in both industrial power generation and commercial aviation applications. To effectively complete this project, the National Energy Technology Laboratory’s Office of Research & Development teamed with MDS Coating Technologies Inc. (MCT), Delta Air Lines - Technical Operations Division (Delta Tech Ops), and Calpine Corporation. The coating targeted for this application was MCT’s Next Generation Coating, version 4 (NGC-v4 - with the new registered trademark name of BlackGold®). The coating is an erosion andmore » corrosion resistant composite nanostructured coating. This coating is comprised of a proprietary ceramic-metallic nano-composite construction which provides enhanced erosion resistance and also retains the aerodynamic geometry of the airfoils. The objective of the commercial aviation portion of the project was to substantiate the coating properties to allow certification from the FAA to apply an erosion-resistant coating in a commercial aviation engine. The goal of the series of tests was to demonstrate that the durability of the airfoils is not affected negatively with the application of the NGC v4 coating. Tests included erosion, corrosion, vibration and fatigue. The results of the testing demonstrated that the application of the coating did not negatively impact the properties of the blades, especially fatigue performance – which is of importance in acceptance for commercial aviation applications. The objective of the industrial gas turbine element of the project was to evaluate the coating as an enabling technology for inlet fogging during the operation of industrial gas turbines. Fluid erosion laboratory scale tests were conducted to simulate inlet fogging conditions. Results of these tests indicated that the application of the erosion resistant NGC-v4 nanocoating

Controlled ultrasound tissue erosion: The role of dynamic interaction between insonation and microbubble activity

PubMed Central

Xu, Zhen; Fowlkes, J. Brian; Rothman, Edward D.; Levin, Albert M.; Cain, Charles A.

2009-01-01

Previous studies showed that ultrasound can mechanically remove tissue in a localized, controlled manner. Moreover, enhanced acoustic backscatter is highly correlated with the erosion process. “Initiation” and “extinction” of this highly backscattering environment were studied in this paper. The relationship between initiation and erosion, variability of initiation and extinction, and effects of pulse intensity and gas saturation on time to initiation (initiation delay time) were investigated. A 788-kHz single-element transducer was used. Multiple pulses at a 3-cycle pulse duration and a 20-kHz pulse repetition frequency were applied. ISPPA values between 1000 and 9000 W/cm2 and gas saturation ranges of 24%–28%, 39%–49%, and 77%–81% were tested. Results show the following: (1) without initiation, erosion was never observed; (2) initiation and extinction of the highly backscattering environment were stochastic in nature and dependent on acoustic parameters; (3) initiation delay times were shorter with higher intensity and higher gas saturation (e.g., the mean initiation delay time was 66.9 s at ISPPA of 4000 W/cm2 and 3.6 ms at ISPPA of 9000 W/cm2); and (4) once initiated by high-intensity pulses, the highly backscattering environment and erosion can be sustained using a significantly lower intensity than that required to initiate the process. PMID:15704435

Anthropogenic control on geomorphic process rates: can we slow down the erosion rates? (Geomorphology Outstanding Young Scientist Award & Penck Lecture)

NASA Astrophysics Data System (ADS)

Vanacker, V.

2012-04-01

The surface of the Earth is changing rapidly, largely in response to anthropogenic perturbation. Direct anthropogenic disturbance of natural environments may be much larger in many places than the (projected) indirect effects of climate change. There is now large evidence that humans have significantly altered geomorphic process rates, mainly through changes in vegetation composition, density and cover. While much attention has been given to the impact of vegetation degradation on geomorphic process rates, I suggest that the pathway of restoration is equally important to investigate. First, vegetation recovery after crop abandonment has a rapid and drastic impact on geomorphic process rates. Our data from degraded catchments in the tropical Andes show that erosion rates can be reduced by up to 100 times when increasing the protective vegetation cover. During vegetation restoration, the combined effects of the reduction in surface runoff, sediment production and hydrological connectivity are stronger than the individual effects together. Therefore, changes in erosion and sedimentation during restoration are not simply the reverse of those observed during degradation. Second, anthropogenic perturbation causes a profound but often temporary change in geomorphic process rates. Reconstruction of soil erosion rates in Spain shows us that modern erosion rates in well-vegetated areas are similar to long-term rates, despite evidence of strong pulses in historical erosion rates after vegetation clearance and agriculture. The soil vegetation system might be resilient to short pulses of accelerated erosion (and deposition), as there might exist a dynamic coupling between soil erosion and production also in degraded environments.

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

Treesearch

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...

Erosion

USDA-ARS?s Scientific Manuscript database

Erosion is the detachment of soil particles and transportation to another location. Wind erosion occurs when wind speed exceeds a critical threshold level, and loose soil particles or soil particles removed by abrasion then move in one of three ways: creep, saltation, and suspension. Erosion by wate...

The management submodel of the Wind Erosion Prediction System

USDA-ARS?s Scientific Manuscript database

The Wind Erosion Prediction System (WEPS) is a process-based, daily time-step, computer model that predicts soil erosion via simulation of the physical processes controlling wind erosion. WEPS is comprised of several individual modules (submodels) that reflect different sets of physical processes, ...

Coercive versus cooperative pollution control: Comparative study of state programs to reduce erosion and sedimentation pollution in urban areas

NASA Astrophysics Data System (ADS)

Burby, Raymond J.

1995-05-01

This article examines coercive and cooperative approaches to implementing state urban erosion and sedimentation pollution control programs. State administrators report serious shortfalls in their ability to control sources of pollution, but comparison of more and less successful programs provides evidence of what states can do to make programs more effective. Key ingredients for a successful state effort include the use of coercion with both the private sector and local government, adequate staffing, application of severe sanctions when violations of state standards are detected, and provision of technical assistance. Many state programs lack one or more of those elements, which explains their inability to adequately control urban erosion and sedimentation pollution.

Oral hygiene products may cause dental erosion.

PubMed

Rytömaa, I; Meurman, J H; Franssila, S; Torkko, H

1989-01-01

The erosive effects of the mouthwashes Calcusan, Salisan and Veadent, and of a tablet, Salivin, meant to be sucked, were studied using enamel blocks from bovine permanent teeth. For comparison, the Hart-Sport sport drink (pH 3.1), which is known to be erosive, and carbonated mineral water Vichy (pH 5.4), which is known to have no erosive effect, were also tested. After two hours of exposure to each test product losses of tooth material were measured by recording the surface profile, using a Dectak profilometer. Changes in the enamel blocks were also studied using a stereomicroscope and a scanning electron microscope (SEM). In the profilometric study, Calcusan was found to have a marked erosive effect (77 +/- 5 microns), four times as severe as the erosive effect of the positive control Hart-Sport (19 +/- 4 microns). Veadent had a less marked effect (3 +/- 1 microns). Salisan and Salivin had no detectable erosive effects and were similar in action to the negative control, carbonated mineral water. From the SEM pictures, Calcusan resulted in an EDTA-type reaction, with dissolution of the peripheral areas of enamel prisms. It is important to recognize that the organic acids and chelating agents in various oral hygiene products may have deleterious effects on teeth.

Dental Erosion in Children with Gastroesophageal Reflux Disease.

PubMed

De Oliveira, Patricia Alves Drummond; Paiva, Saul Martins; De Abreu, Mauro Henrique Nogueira Guimarães; Auad, Sheyla Márcia

2016-01-01

The purpose of this study was to investigate the impact of gastroesophageal reflux disease (GERD) on dental erosion (DE) in children and analyze the association between dental erosion and diet, oral hygiene, and sociodemographic characteristics. This case-control study encompassed 43 two- to 14-year-olds diagnosed positive for GERD by the 24-hour pH monitoring, paired by age group with 136 healthy controls, in Belo Horizonte, Minas Gerais, Brazil. DE was assessed by one calibrated examiner using the O'Sullivan index. A questionnaire was self-administered by parents collecting information regarding sociodemographics, oral hygiene, and dietary habits. Dental erosion experience was compared between the groups, and a stratified analysis was performed (P<0.05). Dental erosion was diagnosed in 10.6 percent (N equals 19) of all the children; 25.6 percent (N equals 11) of GERD children and 5.9 percent (N equals eight) of children without GERD, P=0.001). Dental erosion was not associated with dietary consumption or sociodemographic characteristics in both groups (P≥0.05). Children who used adult toothpaste had a 5.79 higher chance of having dental erosion in the group with GERD. Children diagnosed with gastroesophageal reflux disease were at an increased risk of having dental erosion when compared to healthy subjects; among the GERD children, dental erosion was associated with the use of adult toothpaste.

Critical Source Area Delineation: The representation of hydrology in effective erosion modeling.

NASA Astrophysics Data System (ADS)

Fowler, A.; Boll, J.; Brooks, E. S.; Boylan, R. D.

2017-12-01

Despite decades of conservation and millions of conservation dollars, nonpoint source sediment loading associated with agricultural disturbance continues to be a significant problem in many parts of the world. Local and national conservation organizations are interested in targeting critical source areas for control strategy implementation. Currently, conservation practices are selected and located based on the Revised Universal Soil Loss Equation (RUSLE) hillslope erosion modeling, and the National Resource Conservation Service will soon be transiting to the Watershed Erosion Predict Project (WEPP) model for the same purpose. We present an assessment of critical source areas targeted with RUSLE, WEPP and a regionally validated hydrology model, the Soil Moisture Routing (SMR) model, to compare the location of critical areas for sediment loading and the effectiveness of control strategies. The three models are compared for the Palouse dryland cropping region of the inland northwest, with un-calibrated analyses of the Kamiache watershed using publicly available soils, land-use and long-term simulated climate data. Critical source areas were mapped and the side-by-side comparison exposes the differences in the location and timing of runoff and erosion predictions. RUSLE results appear most sensitive to slope driving processes associated with infiltration excess. SMR captured saturation excess driven runoff events located at the toe slope position, while WEPP was able to capture both infiltration excess and saturation excess processes depending on soil type and management. A methodology is presented for down-scaling basin level screening to the hillslope management scale for local control strategies. Information on the location of runoff and erosion, driven by the runoff mechanism, is critical for effective treatment and conservation.

Seasonal variation and climate change impact in Rainfall Erosivity across Europe

NASA Astrophysics Data System (ADS)

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

2017-04-01

residues, reduced tillage) in regions with high erosivity. Besides soil erosion mapping, the intra-annual analysis of rainfall erosivity is an important step towards flood prevention, hazard mitigation, ecosystem services, land use change and agricultural production. The application of REDES in combination with moderate climate change scenarios scenario (HadGEM RCP 4.5) resulted in predictions of erosivity in 2050. The overall increase of rainfall erosivity in Europe by 18% until 2050 are in line with projected increases of 17% for the U.S.A. The predicted mean rise of erosivity is also expected to increase the threat of soil erosion in Europe. The most noticeable increase of erosivity is projected for North-Central Europe, the English Channel, The Netherlands and Northern France. On the contrary, the Mediterranean basin show mixed trends. The success story with the compilation of REDES and first rainfall erosivity map of Europe was a driver to implement a Global Rainfall Erosivity Database (GloREDa). During the last 3 years, JRC was leading an effort to collect high temporal resolution rainfall data worldwide. In collaboration with 50 scientists worldwide and 100+ Meteorological and environmental Organisations, we have developed a Global Erosivity Database. In this database, we managed to include calculated erosivity values for 3,625 stations covering 63 countries worldwide.

Wind Erosion Caused by Land Use Changes Significantly Reduces Ecosystem Carbon Storage and Carbon Sequestration Potentials in Grassland

NASA Astrophysics Data System (ADS)

Li, P.; Chi, Y. G.; Wang, J.; Liu, L.

2017-12-01

Wind erosion exerts a fundamental influence on the biotic and abiotic processes associated with ecosystem carbon (C) cycle. However, how wind erosion under different land use scenarios will affect ecosystem C balance and its capacity for future C sequestration are poorly quantified. Here, we established an experiment in a temperate steppe in Inner Mongolia, and simulated different intensity of land uses: control, 50% of aboveground vegetation removal (50R), 100% vegetation removal (100R) and tillage (TI). We monitored lateral and vertical carbon flux components and soil characteristics from 2013 to 2016. Our study reveals three key findings relating to the driving factors, the magnitude and consequence of wind erosion on ecosystem C balance: (1) Frequency of heavy wind exerts a fundamental control over the severity of soil erosion, and its interaction with precipitation and vegetation characteristics explained 69% variation in erosion intensity. (2) With increases in land use intensity, the lateral C flux induced by wind erosion increased rapidly, equivalent to 33%, 86%, 111% and 183% of the net ecosystem exchange of the control site under control, 50R, 100R and TI sites, respectively. (3) After three years' treatment, erosion induced decrease in fine fractions led to 31%, 43%, 85% of permanent loss of C sequestration potential in the surface 5cm soil for 50R, 100R and TI sites. Overall, our study demonstrates that lateral C flux associated with wind erosion is too large to be ignored. The loss of C-enriched fine particles not only reduces current ecosystem C content, but also results in irreversible loss of future soil C sequestration potential. The dynamic soil characteristics need be considered when projecting future ecosystem C balance in aeolian landscape. We also propose that to maintain the sustainability of grassland ecosystems, land managers should focus on implementing appropriate land use rather than rely on subsequent managements on degraded soils.

The South Carolina Coastal Erosion Study: Integrated Circulation and Sediment Transport Studies. A Project Overview.

NASA Astrophysics Data System (ADS)

Voulgaris, G.; Warner, J. C.; Work, P. A.; Hanes, D. M.; Haas, K. A.

2004-12-01

The South Carolina Coastal Erosion Study (SCCES) is a cooperative research program funded by the U.S. Geological Survey Coastal and Marine Geology Program and managed by the South Carolina Sea Grant Consortium. The main objective of the study is to understand the factors and processes that control coastal sediment movement along the northern part of the South Carolina coast while at the same time advance our basic understanding of circulation, wave propagation and sediment transport processes. Earlier geological framework studies carried out by the same program provided detailed data on bathymetry, bottom sediment thickness and grain size distribution. They identified an extensive (10km long, 2km wide) sand body deposit located in the inner shelf that has potential use for beach nourishment. The main objectives are to: (1) identify the role of wind-driven circulation in controlling regional sediment distribution on the SC shelf; (2) examine the hypothesis that the shoal is of the "fair-weather type" with bedload being the dominant sediment transport mode and the tidally-averaged flow being at different directions at the two flanks of the shoal; (3) investigate the possibility that the sediment source for the shoal is derived from the nearshore as the result of the convergence of the longshore sediment transport; and finally, (4) quantify the control that the shoal exerts on the nearshore conditions through changes on the wave energy propagation characteristics. Field measurements and numerical modeling techniques are utilized in this project. Two deployments of oceanographic and sediment transport systems took place for a period of 6 months (October 2003 to April 2004) measuring wind forcing, vertical distribution of currents, stratification, and wave spectral characteristics. Further, bed-flow interactions were measured at two locations, with instrumented tripods equipped with pairs of ADVs for measuring turbulence, PC-ADPs for measuring vertical current profiles

Evaluation of compost/mulch as highway embankment erosion control in Louisiana at the plot-scale

NASA Astrophysics Data System (ADS)

Bakr, Noura; Weindorf, David C.; Zhu, Yuanda; Arceneaux, Allen E.; Selim, H. M.

2012-10-01

SummaryTotal suspended solids (TSS) and associated turbidity in runoff water are considered the most problematic nonpoint source pollutant of Louisiana surface waters. With high precipitation in Louisiana, attention should be given to controlling highway right-of-way erosion. The use of compost/mulch for erosion control enhances soil conservation and substantially reduces erosion. The main objective of this study was to assess the effect of compost/mulch placement on runoff water quality on roadsides. Our hypothesis was that the use of compost/mulch would significantly reduce TSS and turbidity in runoff from highway right-of-ways in Louisiana. Two locations constituting four sites and eight individual plots were chosen; one in an active highway construction area and another in an established area plagued by continual rill and sheet erosion. Thicknesses of compost/mulch (5 and 10 cm), slope inclination (10-34%), and tillage practices (till vs. no-till) were evaluated. Runoff, triggered by storm water events, was collected using ISCO auto-samplers from June 2010 to August 2011 and the samples were analyzed for TSS, turbidity, biochemical oxygen demand, electrical conductivity, and pH. The results of factor analysis showed that the compost/mulch thickness was the most influential variable affecting water quality. Two samples t-test results indicated that TSS and turbidity were significantly different across all comparative variables; construction activities, compost/mulch applications, and tillage practices. The results confirmed the effectiveness of compost/mulch cover as a successful best management practice. Specifically decreases in TSS of 70% and 74% were achieved for the 5 cm and 10 cm compost/mulch application when compared to no compost/mulch, respectively. Light tillage application increased TSS as much as 67%. Therefore, light tillage is not recommended since it decreased the effectiveness of compost/mulch in reducing runoff and sediment losses.

Anthropogenic Increase Of Soil Erosion In The Gangetic Plain Revealed By Geochemical Budget Of Erosion

NASA Astrophysics Data System (ADS)

Galy, V.; France-Lanord, C.; Galy, A.; Gaillardet, J.

2007-12-01

Tectonic and climatic factors are the key natural variables controlling the erosion through complex interactions. Nonetheless, over the last few hundred years, human activity also exerts a dominant control in response to extensive land use. The geochemical budget of erosion allows the balance between the different erosion processes to be quantified. The chemical composition of river sediment results from the chemical composition of the source rock modified by (1) weathering reactions occurring during erosion and (2) physical segregation during transport. If erosion is at steady state, the difference between the chemical composition of source rocks and that of river sediments must therefore be counterbalanced by the dissolved flux. However, climatic variations or anthropic impact can induce changes in the erosion distribution in a given basin resulting in non steady state erosion. Using a mass balance approach, the comparison of detailed geochemical data on river sediments with the current flux of dissolved elements allows the steady state hypothesis to be tested. In this study, we present a geochemical budget of weathering for the Ganga basin, one of the most densely populated basin in the world, based on detailed sampling of Himalayan rivers and of the Ganga in the delta. Sampling includes depth profile in the river, to assess the variability generated by transport processes. Himalayan river sediments are described by the dilution of an aluminous component (micas + clays + feldspars) by quartz. Ganga sediments on the other hand correspond to the mixing of bedload, similar to coarse Himalayan sediments, with an aluminous component highly depleted in alkaline elements. Compared with the dissolved flux, the depletion of alkaline elements in Ganga sediments shows that the alkaline weathering budget is imbalanced. This imbalance results from an overabundance of fine soil material in the Ganga sediment relative to other less weathered material directly derived from

Techniques for establishing vegetation for long-term erosion control on disturbed slopes in Alabama

Treesearch

M. Dougherty; A. Baharanyi; B. Guertal; J. Grace

2010-01-01

One year results from 21 outdoor erosion and sediment control plots constructed in 2008 on a 4:1 slope are presented. The study objectives were to evaluate; 1) the effects of incorporating lime and fertilizer on establishment of bermudagrass on steep slopes, 2) the differences in bermudagrass establishment as a function of temporary covers including wheat straw,...

Gastroesophageal Reflux is Not Associated with Dental Erosion in Children

PubMed Central

Wild, Yvette K.; Heyman, Melvin B.; Vittinghoff, Eric; Dalal, Deepal H.; Wojcicki, Janet M.; Clark, Ann L.; Rechmann, Beate; Rechmann, Peter

2011-01-01

Background & Aims Dental erosion is a complication of gastroesophageal reflux (GER) in adults; in children, it is not clear if GER has a role in dental pathologic conditions. Dietary intake, oral hygiene, high bacterial load, and decreased salivary flow might contribute independently to GER development or dental erosion, but their potential involvement in dental erosion from GER is not understood. We investigated the prevalence of dental erosion among children with and without GER symptoms, and whether salivary flow rate or bacterial load contribute to location-specific dental erosion. Methods We performed a cross-sectional study of 59 children (ages 9–17 y) with symptoms of GER and 20 asymptomatic children (controls); all completed a questionnaire on dietary exposure. Permanent teeth were examined for erosion into dentin, erosion locations, and affected surfaces. The dentist was not aware of GER status, nor was the gastroenterologist aware of dental status. Stimulated salivary flow was measured and salivary bacterial load was calculated for total bacteria, Streptococcus mutans and Lactobacilli. Results Controlling for age, dietary intake, and oral hygiene, there was no association between GER symptoms and dental erosion, by tooth location or affected surface. Salivary flow did not correlate with GER symptoms or erosion. Erosion location and surface were independent of total bacteria and levels of Streptococcus mutans and Lactobacilli. Conclusions Location-specific dental erosion is not associated with GER, salivary flow, or bacterial load. Prospective studies are required to determine the pathogenesis of GER-associated dental erosion and the relationship between dental caries to GER and dental erosion. PMID:21820389

Gastroesophageal reflux is not associated with dental erosion in children.

PubMed

Wild, Yvette K; Heyman, Melvin B; Vittinghoff, Eric; Dalal, Deepal H; Wojcicki, Janet M; Clark, Ann L; Rechmann, Beate; Rechmann, Peter

2011-11-01

Dental erosion is a complication of gastroesophageal reflux (GER) in adults; in children, it is not clear if GER has a role in dental pathologic conditions. Dietary intake, oral hygiene, high bacterial load, and decreased salivary flow might contribute independently to GER development or dental erosion, but their potential involvement in dental erosion from GER is not understood. We investigated the prevalence of dental erosion among children with and without GER symptoms, and whether salivary flow rate or bacterial load contribute to location-specific dental erosion. We performed a cross-sectional study of 59 children (ages, 9-17 y) with symptoms of GER and 20 asymptomatic children (controls); all completed a questionnaire on dietary exposure. Permanent teeth were examined for erosion into dentin, erosion locations, and affected surfaces. The dentist was not aware of GER status, and the gastroenterologist was not aware of dental status. Stimulated salivary flow was measured and salivary bacterial load was calculated for total bacteria, Streptococcus mutans, and Lactobacilli. Controlling for age, dietary intake, and oral hygiene, there was no association between GER symptoms and dental erosion by tooth location or affected surface. Salivary flow did not correlate with GER symptoms or erosion. Erosion location and surface were independent of total bacteria and levels of Streptococcus mutans and Lactobacilli. Location-specific dental erosion is not associated with GER, salivary flow, or bacterial load. Prospective studies are required to determine the pathogenesis of GER-associated dental erosion and the relationship between dental caries to GER and dental erosion. Copyright © 2011 AGA Institute. Published by Elsevier Inc. All rights reserved.

A wood-strand material for wind erosion control: effects on total sediment loss, PM10 vertical flux, and PM10 loss.

PubMed

Copeland, N S; Sharratt, B S; Wu, J Q; Foltz, R B; Dooley, J H

2009-01-01

Fugitive dust from eroding land poses risks to environmental quality and human health, and thus, is regulated nationally based on ambient air quality standards for particulate matter with mean aerodynamic diameter < or = 10 microm (PM10) established in the Clean Air Act. Agricultural straw has been widely used for rainfall-induced erosion control; however, its performance for wind erosion mitigation has been less studied, in part because straw is mobile at moderate wind velocities. A wood-based long-strand material has been developed for rainfall-induced erosion control and has shown operational promise for control of wind-induced erosion and dust emissions from disturbed sites. The purpose of this study was to evaluate the efficacy of both agricultural straw and wood-strand materials in controlling wind erosion and fugitive dust emissions under laboratory conditions. Wind tunnel tests were conducted to compare wood strands of several geometries to agricultural wheat straw and bare soil in terms of total sediment loss, PM10 vertical flux, and PM10 loss. Results indicate that the types of wood strands tested are stable at wind speeds of up to 18 m s(-1), while wheat straw is only stable at speeds of up to 6.5 m s(-1). Wood strands reduced total sediment loss and PM10 emissions by 90% as compared to bare soil across the range of wind speeds tested. Wheat straw did not reduce total sediment loss for the range of speeds tested, but did reduce PM10 emissions by 75% compared to a bare soil at wind speeds of up to 11 m s(-1).

Erosion Coatings for High-Temperature Polymer Composites: A Collaborative Project With Allison Advanced Development Company

NASA Technical Reports Server (NTRS)

Sutter, James K.

2000-01-01

The advantages of replacing metals in aircraft turbine engines with high-temperature polymer matrix composites (PMC's) include weight savings accompanied by strength improvements, reduced part count, and lower manufacturing costs. Successfully integrating high-temperature PMC's into turbine engines requires several long-term characteristics. Resistance to surface erosion is one rarely reported property of PMC's in engine applications because PMC's are generally softer than metals and their erosion resistance suffers. Airflow rates in stationary turbine engine components typically exceed 2.3 kg/sec at elevated temperatures and pressures. In engine applications, as shown in the following photos, the survivability of PMC components is clearly a concern, especially when engine and component life-cycle requirements become longer. Although very few publications regarding the performance of erosion coatings on PMC's are available particularly in high-temperature applications the use of erosion-resistant coatings to significantly reduce wear on metallic substrates is well documented. In this study initiated by the NASA Glenn Research Center at Lewis Field, a low-cost (less than $140/kg) graphite-fiber-reinforced T650 35/PMR 15 sheet-molding compound was investigated with various coatings. This sheet-molding compound has been compression molded into many structurally complicated components, such as shrouds for gas turbine inlet housings and gearboxes. Erosion coatings developed for PMC s in this study consisted of a two-layered system: a bondcoat sprayed onto a cleaned PMC surface, followed by an erosion-resistant, hard topcoat sprayed onto the bondcoat as shown in following photomicrograph. Six erosion coating systems were evaluated for their ability to withstand harsh thermal cycles, erosion resistance (ASTM G76 83 "Standard Practice for Conducting Erosion Tests by Solid Particle Impingement Using Gas Jets") using Al2O3, and adhesion to the graphite fiber polyimide

Geomorphic considerations for erosion prediction

USGS Publications Warehouse

Osterkamp, W.R.; Toy, T.J.

1997-01-01

Current soil-erosion prediction technology addresses processes of rainsplash, overland-flow sediment transport, and rill erosion in small watersheds. The effects of factors determining sediment yield from larger-scale drainage basins, in which sediment movement is controlled by the combined small-scale processes and a complex set of channel and other basin-scale sediment-delivery processes, such as soil creep, bioturbation, and accelerated erosion due to denudation of vegetation, have been poorly evaluated. General suggestions are provided for the development of erosion-prediction technology at the geomorphic or drainage-basin scale based on the separation of sediment-yield data for channel and geomorphic processes from those of field-scale soil loss. An emerging technology must consider: (1) the effects on sediment yield of climate, geology and soils, topography, biotic interactions with other soil processes, and land-use practices; (2) all processes of sediment delivery to a channel system; and (3) the general tendency in most drainage basins for progressively greater sediment storage in the downstream direction.

The relative importance of different grass components in controlling runoff and erosion on a hillslope under simulated rainfall

NASA Astrophysics Data System (ADS)

Li, Changjia; Pan, Chengzhong

2018-03-01

The effects of vegetation cover on overland flow and erosion processes on hillslopes vary with vegetation type and spatial distribution and the different vegetation components, including the above- and below-ground biomass. However, few attempts have been made to quantify how these factors affect erosion processes. Field experimental plots (5 m × 2 m) with a slope of approximately 25° were constructed and simulated rainfall (60 mm hr-1) (Rainfall) and simulated rainfall combined with upslope overland flow (20 L min-1) (Rainfall + Flow) were applied. Three grass species were planted, specifically Astragalus adsurgens (A. adsurgens), Medicago sativa (M. sativa) and Cosmos bipinnatus (C. bipinnatus). To isolate and quantify the relative contributions of the above-ground grass parts (stems, litter cover and leaves) and the roots to reducing surface runoff and erosion, each of the three grass species was subjected to three treatments: intact grass control (IG), no litter or leaves (only the grass stems and roots were reserved) (NLL), and only roots remaining (OR). The results showed that planting grass significantly reduced overland flow rate and velocity and sediment yield, and the mean reductions were 21.8%, 29.1% and 67.1%, respectively. M. sativa performed the best in controlling water and soil losses due to its thick canopy and dense, fine roots. Grasses reduced soil erosion mainly during the early stage of overland flow generation. The above-ground grass parts primarily contributed to reducing overland flow rate and velocity, with mean relative contributions of 64% and 86%, respectively. The roots played a predominant role in reducing soil erosion, with mean contribution of 84%. Due to the impact of upslope inflow, overland flow rate and velocity and sediment yield increased under the Rainfall + Flow conditions. The results suggest that grass species on downslope parts of semi-arid hillslopes performed better in reducing water and soil losses. This study is

Monsoonal vs. glacial control on erosion and sediment storage in the Himalayan rain shadow, Zanskar River, northwest India

NASA Astrophysics Data System (ADS)

Jonell, Tara; Clift, Peter; Carter, Andrew; Böning, Philipp; Wittmann, Hella

2016-04-01

Summer monsoon precipitation strongly controls erosion and sediment storage in the frontal Himalaya but the relationship between monsoonal variability and erosion is less well-constrained beyond the High Himalayan topographic divide in the rain shadow. Here we establish a Quaternary erosional history for a rain shadow tributary of the upper Indus River system, the Zanskar River, by applying several sediment provenance techniques to modern and dated terrace river sediments. We evaluate if there are temporal links between sediment storage and moisture supply to the rain shadow and if regions like the Zanskar River basin play a significant role in controlling total sediment flux to the Indus River. We compile bulk sediment petrography and Sr and Nd isotope geochemistry, detrital U-Pb zircon and apatite fission track dating with in-situ 10Be cosmogenic radionuclide techniques to identify patterns of erosion and sediment production across Zanskar. Bulk petrography, Sr and Nd isotope geochemistry, and U-Pb detrital zircon spectra of modern and older terrace sediments indicate high rates of erosion along the Greater Himalaya in the Zanskar River basin. We find that the wettest and most glaciated subcatchment dominates the bulk sediment provenance signal, with only moderate input from other tributaries, and that other basin parameters cannot explain our observations. Catchment-averaged in-situ 10Be cosmogenic nuclide concentrations of modern sediments indicate erosion rates up to ˜1.2 mm y-1 but show strong dilution attributed to glacial sediment recycling into the modern river, suggesting rates nearer 0.4-0.6 mm•y-1. These rates are consistent with longer-term rates of incision (0.3-0.7 mm•y-1) calculated from detrital apatite fission track ages, and incision rates inferred from Late Glacial and Holocene terraces near the Zanskar-Indus confluence. Our findings suggest that sediment production in glaciated Himalayan rain shadow environments like Zanskar is largely

Does WEPP meet the specificity of soil erosion in steep mountain regions?

USDA-ARS?s Scientific Manuscript database

We chose the USDA-ARS-WEPP model (Water Erosion Prediction Project) to describe the soil erosion in the Urseren valley (Central Switzerland) as it seems to be one of the most promising models for steep mountain environments. Crucial model parameters were determined in the field (slope, plant species...

Trend analyses of sediment data for the DEC project

USGS Publications Warehouse

Rebich, Richard Allen

1995-01-01

Daily stream discharge, suspended-sediment concentration, and suspended-sediment discharge data were collected at eight sites in six watersheds of the Demonstration Erosion Control project in the Yazoo River Basin in north-central Mississippi during the period July 1985 through September 1991. The project is part of an ongoing interagency program of planning, design, construction, monitoring, and evaluation to alleviate flooding, erosion, sedimentation, and water-quality problems for watersheds located in the bluff hills upstream of the Mississippi River alluvial plain. This paper presents preliminary results of trend analyses for stream discharge and sediment data for the eight project sites. More than 550 stream discharge measurements and 20,000 suspended-sediment samples have been collected at the eight sites since 1985.

ERMiT: Estimating Post-Fire Erosion in Probabilistic Terms

NASA Astrophysics Data System (ADS)

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

2006-12-01

Mitigating the impact of post-wildfire runoff and erosion on life, property, and natural resources have cost the United States government tens of millions of dollars over the past decade. The decision of where, when, and how to apply the most effective 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) is a web-based application that estimates erosion in probabilistic terms on burned and recovering forest, range, and chaparral lands. Unlike most erosion prediction models, ERMiT does not provide `average annual erosion rates;' rather, it provides a distribution of erosion rates with the likelihood of their occurrence. ERMiT combines rain event variability with spatial and temporal variabilities of hillslope burn severity, soil properties, and ground cover to estimate Water Erosion Prediction Project (WEPP) model input parameter values. Based on 20 to 40 individual WEPP runs, ERMiT produces a distribution of rain event erosion rates with a probability of occurrence for each of five post-fire years. Over the 5 years of modeled recovery, the occurrence probability of the less erodible soil parameters is increased and the occurrence probability of the more erodible soil parameters is decreased. In addition, the occurrence probabilities and the four spatial arrangements of burn severity (arrangements of overland flow elements (OFE's)), are shifted toward lower burn severity with each year of recovery. These yearly adjustments are based on field measurements made through post-fire recovery periods. ERMiT also provides rain event erosion rate distributions for hillslopes that have been treated with seeding, straw mulch, straw wattles and contour-felled log erosion barriers. Such output can help managers make erosion mitigation treatment decisions based on the probability of high sediment yields occurring, the value of resources at risk for damage, cost, and

Uncertainty of climate change impacts on soil erosion from cropland in central Oklahoma

USDA-ARS?s Scientific Manuscript database

Impacts of climate change on soil erosion and the potential need for additional conservation actions are typically estimated by applying a hydrologic and soil erosion model under present and future climate conditions defined by an emission scenario. Projecting future climate conditions harbors sever...

An empirical approach to estimate soil erosion risk in Spain.

PubMed

Martín-Fernández, Luis; Martínez-Núñez, Margarita

2011-08-01

Soil erosion is one of the most important factors in land degradation and influences desertification worldwide. In 2001, the Spanish Ministry of the Environment launched the 'National Inventory of Soil Erosion (INES) 2002-2012' to study the process of soil erosion in Spain. The aim of the current article is to assess the usefulness of this National Inventory as an instrument of control, measurement and monitoring of soil erosion in Spain. The methodology and main features of this National Inventory are described in detail. The results achieved as of the end of May 2010 are presented, together with an explanation of the utility of the Inventory as a tool for planning forest hydrologic restoration, soil protection, erosion control, and protection against desertification. Finally, the authors make a comparative analysis of similar initiatives for assessing soil erosion in other countries at the national and European levels. Copyright © 2011 Elsevier B.V. All rights reserved.

Materials for Advanced Turbine Engines (MATE). Project 4: Erosion resistant compressor airfoil coating

NASA Technical Reports Server (NTRS)

Rashid, J. M.; Freling, M.; Friedrich, L. A.

1987-01-01

The ability of coatings to provide at least a 2X improvement in particulate erosion resistance for steel, nickel and titanium compressor airfoils was identified and demonstrated. Coating materials evaluated included plasma sprayed cobalt tungsten carbide, nickel carbide and diffusion applied chromium plus boron. Several processing parameters for plasma spray processing and diffusion coating were evaluated to identify coating systems having the most potential for providing airfoil erosion resistance. Based on laboratory results and analytical evaluations, selected coating systems were applied to gas turbine blades and evaluated for surface finish, burner rig erosion resistance and effect on high cycle fatigue strength. Based on these tests, the following coatings were recommended for engine testing: Gator-Gard plasma spray 88WC-12Co on titanium alloy airfoils, plasma spray 83WC-17Co on steel and nickel alloy airfoils, and Cr+B on nickel alloy airfoils.

Model development and applications at the USDA-ARS National Soil Erosion Research Laboratory

USDA-ARS?s Scientific Manuscript database

The United States Department of Agriculture (USDA) has a long history of development of soil erosion prediction technology, initially with empirical equations like the Universal Soil Loss Equation (USLE), and more recently with process-based models such as the Water Erosion Prediction Project (WEPP)...

The effect of enamel proteins on erosion

NASA Astrophysics Data System (ADS)

Baumann, T.; Carvalho, T. S.; Lussi, A.

2015-10-01

Enamel proteins form a scaffold for growing hydroxyapatite crystals during enamel formation. They are then almost completely degraded during enamel maturation, resulting in a protein content of only 1% (w/v) in mature enamel. Nevertheless, this small amount of remaining proteins has important effects on the mechanical and structural properties of enamel and on the electrostatic properties of its surface. To analyze how enamel proteins affect tooth erosion, human enamel specimens were deproteinated. Surface microhardness (SMH), surface reflection intensity (SRI) and calcium release of both deproteinated and control specimens were monitored while continuously eroding them. The deproteination itself already reduced the initial SMH and SRI of the enamel significantly (p < 0.001 and p < 0.01). During the course of erosion, the progression of all three evaluated parameters differed significantly between the two groups (p < 0.001 for each). The deproteinated enamel lost its SMH and SRI faster, and released more calcium than the control group, but these differences were only significant at later stages of erosion, where not only surface softening but surface loss can be observed. We conclude that enamel proteins have a significant effect on erosion, protecting the enamel and slowing down the progression of erosion when irreversible surface loss starts to occur.

The effect of enamel proteins on erosion

PubMed Central

Baumann, T.; Carvalho, T. S.; Lussi, A.

2015-01-01

Enamel proteins form a scaffold for growing hydroxyapatite crystals during enamel formation. They are then almost completely degraded during enamel maturation, resulting in a protein content of only 1% (w/v) in mature enamel. Nevertheless, this small amount of remaining proteins has important effects on the mechanical and structural properties of enamel and on the electrostatic properties of its surface. To analyze how enamel proteins affect tooth erosion, human enamel specimens were deproteinated. Surface microhardness (SMH), surface reflection intensity (SRI) and calcium release of both deproteinated and control specimens were monitored while continuously eroding them. The deproteination itself already reduced the initial SMH and SRI of the enamel significantly (p < 0.001 and p < 0.01). During the course of erosion, the progression of all three evaluated parameters differed significantly between the two groups (p < 0.001 for each). The deproteinated enamel lost its SMH and SRI faster, and released more calcium than the control group, but these differences were only significant at later stages of erosion, where not only surface softening but surface loss can be observed. We conclude that enamel proteins have a significant effect on erosion, protecting the enamel and slowing down the progression of erosion when irreversible surface loss starts to occur. PMID:26468660

Soil Erosion Study on the Chinese Loess Plateau

NASA Astrophysics Data System (ADS)

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.

Climate Change Impacts on Sediment Transport In a Lowland Watershed System: Controlling Processes and Projection

NASA Astrophysics Data System (ADS)

al Aamery, N. M. H.; Mahoney, D. T.; Fox, J.

2017-12-01

Future climate change projections suggest extreme impacts on watershed hydrologic systems for some regions of the world including pronounced increases in surface runoff and instream flows. Yet, there remains a lack of research focused on how future changes in hydrologic extremes, as well as relative hydrologic mean changes, impact sediment redistribution within a watershed and sediment flux from a watershed. The authors hypothesized that variations in mean and extreme changes in turn may impact sediments in depositional and erosional dominance in a manner that may not be obvious to the watershed manager. Therefore, the objectives of this study were to investigate the inner processes connecting the combined effect of extreme climate change projections on the vegetation, upland erosion, and instream processes to produce changes in sediment redistribution within watersheds. To do so, research methods were carried out by the authors including simulating sediment processes in forecast and hindcast periods for a lowland watershed system. Publically available climate realizations from several climate factors and the Soil Water Assessment Tool (SWAT) were used to predict hydrologic conditions for the South Elkhorn Watershed in central Kentucky, USA to 2050. The results of the simulated extreme and mean hydrological components were used in simulating upland erosion with the connectivity processes consideration and thereafter used in building and simulating the instream erosion and deposition of sediment processes with the consideration of surface fine grain lamina (SFGL) layer controlling the benthic ecosystem. Results are used to suggest the dominance of erosional and depositional redistribution of sediments under different scenarios associated with extreme and mean hydrologic forecasting. The results are discussed in reference to the benthic ecology of the stream system providing insight on how water managers might consider sediment redistribution in a changing climate.

Integrated watershed management for saturation excess generated runoff, erosion and nutrient control

USDA-ARS?s Scientific Manuscript database

Understanding the basic hydrology and erosion is vital for effective management and utilization of water resources and soil conservation planning. An important question for judging effectiveness of soil and water conservation practices is whether runoff erosion and nutrient loss is affected by infil...

Control of high-Z PFC erosion by local gas injection in DIII-D

NASA Astrophysics Data System (ADS)

Rudakov, D. L.; Stangeby, P. C.; Wong, C. P. C.; McLean, A. G.; Wampler, W. R.; Watkins, J. G.; Boedo, J. A.; Briesemeister, A.; Buchenauer, D. A.; Chrobak, C. P.; Elder, J. D.; Fenstermacher, M. E.; Guo, H. Y.; Lasnier, C. J.; Leonard, A. W.; Maingi, R.; Moyer, R. A.

2015-08-01

Reduced erosion of a high-Z PFC divertor surface was observed in DIII-D with local injection of methane and deuterium gases. Molybdenum-coated silicon samples were exposed in the lower divertor of DIII-D using DiMES under plasma conditions previously shown to cause significant net erosion of Mo. Three exposures with 13CH4 and one exposure with D2 gas injection about 12 cm upstream of the samples located within 1-2 cm of the attached strike point were performed. Reduction of Mo erosion was evidenced in-situ by the suppression of MoI line radiation at 386.4 nm once the gas injection started. Post-mortem ion beam analysis demonstrated that the net erosion of molybdenum near the center of the samples exposed with 13CH4 injection was below the measurement resolution of 0.5 nm, corresponding to a rate of ⩽0.04 nm/s. Compared to the previously measured erosion rates, this constitutes a reduction by a factor of >10.

15 CFR 923.25 - Shoreline erosion/mitigation planning.

Code of Federal Regulations, 2011 CFR

2011-01-01

... effects of, and studying and evaluating ways to control, or lessen the impact of, shoreline erosion... must include an identification and description of enforceable policies, legal authorities, funding techniques and other techniques that will be used to manage the effects of erosion, including potential...

15 CFR 923.25 - Shoreline erosion/mitigation planning.

Code of Federal Regulations, 2014 CFR

2014-01-01

... (Continued) NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE OCEAN AND COASTAL... effects of, and studying and evaluating ways to control, or lessen the impact of, shoreline erosion, including potential impacts of sea level rise, and to restore areas adversely affected by such erosion. This...

15 CFR 923.25 - Shoreline erosion/mitigation planning.

Code of Federal Regulations, 2012 CFR

2012-01-01

... (Continued) NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE OCEAN AND COASTAL... effects of, and studying and evaluating ways to control, or lessen the impact of, shoreline erosion, including potential impacts of sea level rise, and to restore areas adversely affected by such erosion. This...

15 CFR 923.25 - Shoreline erosion/mitigation planning.

Code of Federal Regulations, 2013 CFR

2013-01-01

... (Continued) NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE OCEAN AND COASTAL... effects of, and studying and evaluating ways to control, or lessen the impact of, shoreline erosion, including potential impacts of sea level rise, and to restore areas adversely affected by such erosion. This...

An Economic Analysis of USDA Erosion Control Programs: A New Perspective. Agricultural Economic Report No. 560.

ERIC Educational Resources Information Center

Strohbehn, Roger, Ed.

A study analyzed the total (public and private) economic costs and benefits of three U.S. Department of Agriculture erosion control programs. These were the Conservation Technical Assistance Program, Great Plains Conservation Program, and Agricultural Conservation Program. Significant efforts at funding for current programs were directed to…

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

PubMed

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.

Structural practices for controlling sediment transport from erosion

NASA Astrophysics Data System (ADS)

Gabriels, Donald; Verbist, Koen; Van de Linden, Bruno

2013-04-01

Erosion on agricultural fields in the hilly regions of Flanders, Belgium has been recognized as an important economical and ecological problem that requires effective control measures. This has led to the implementation of on-site and off-site measures such as reduced tillage and the installation of grass buffers trips, and dams made of vegetative materials. Dams made out of coir (coconut) and wood chips were evaluated on three different levels of complexity. Under laboratory conditions, one meter long dams were submitted to two different discharges and three sediment concentrations under two different slopes, to assess the sediment delivery ratios under variable conditions. At the field scale, discharge and sediment concentrations were monitored under natural rainfall conditions on six 3 m wide plots, of which three were equipped with coir dams, while the other three served as control plots. The same plots were also used for rainfall simulations, which allowed controlling sediment delivery boundary conditions more precisely. Results show a clear advantage of these dams to reduce discharge by minimum 49% under both field and laboratory conditions. Sediment delivery ratios (SDR) were very small under laboratory and field rainfall simulations (4-9% and 2% respectively), while larger SDRs were observed under natural conditions (43%), probably due to the small sediment concentrations (1-5 g l-1) observed and as such a larger influence of boundary effects. Also a clear enrichment of larger sand particles (+167%) could be observed behind the dams, showing a significant selective filtering effect.

Nonmonotonic and spatial-temporal dynamic slope effects on soil erosion during rainfall-runoff processes

NASA Astrophysics Data System (ADS)

Wu, Songbai; Yu, Minghui; Chen, Li

2017-02-01

The slope effect on flow erosivity and soil erosion still remains a controversial issue. This theoretical framework explained and quantified the direct slope effect by coupling the modified Green-Ampt equation accounting for slope effect on infiltration, 1-D kinematic wave overland flow routing model, and WEPP soil erosion model. The flow velocity, runoff rate, shear stress, interrill, and rill erosion were calculated on 0°-60° isotropic slopes with equal horizontal projective length. The results show that, for short-duration rainfall events, the flow erosivity and erosion amounts exhibit a bell-shaped trend which first increase with slope gradient, and then decrease after a critical slope angle. The critical slope angles increase significantly or even vanish with increasing rainfall duration but are nearly independent of the slope projective length. The soil critical shear stress, rainfall intensity, and temporal patterns have great influences on the slope effect trend, while the other soil erosion parameters, soil type, hydraulic conductivity, and antecedent soil moisture have minor impacts. Neglecting the slope effect on infiltration would generate smaller erosion and reduce critical slope angles. The relative slope effect on soil erosion in physically based model WEPP was compared to those in the empirical models USLE and RUSLE. The trends of relative slope effect were found quite different, but the difference may diminish with increasing rainfall duration. Finally, relatively smaller critical slope angles could be obtained with the equal slope length and the range of variation provides a possible explanation for the different critical slope angles reported in previous studies.

Erosion Control Management Plan for Army Training Lands

DTIC Science & Technology

1990-07-01

Functional Appropriateness of Control Appropriateness of Control for Natural Conditions Environmental Impact Considerations Appropriateness of Control...construction, maintenance, and repair projects are often related to environmental protection standards and natural resource guidelines. In such cases...SEP 17 90" The Army faces major land management issues in SEP 1 9O maintaining its training areas to be environmentally sound and support the mission

Short- term effects of post-fire logging on runoff and soil erosion at two spatial scales

NASA Astrophysics Data System (ADS)

Malvar, Maruxa; Silva, Flavio; Prats, Sergio; Vieira, Diana; Keizer, Jacob

2017-04-01

Logging is the most common management practice after wildfires in forested areas in Portugal. Clearcutting is undertaken to recover burnt timber resources, to control resprouting, notably in the case of eucalypt plantations, and to reduce the risks of possible insect plagues, notably in the case of maritime pine because of the nematode plague. Still, relatively little is known about the combined effect of wildfire and post-fire logging on erosion processes. In the framework of the EU-FP7 project RECARE (www.recare-project.eu), the ESP team of the University of Aveiro set up an experiment to quantify the hydrological and erosion impacts of post-fire logging, at the scale of both 0.25 m2 micro-plots and 16 m2 plots. A eucalypt slope burnt in August 2015 by a moderate intensity fire and logged in September 2015 was selected for this study. The burned trees were harvested with a chainsaw, while the logs were piled with a rubber wheeled forwarder tractor. Following logging, two distinct sub-areas were identified within the logged slope based on soil disturbance: an area where the forwarder wheels had left marked trails ("trail"), and an area where such trails were absent ("control"). Three micro-plots and three plots were installed in the control area, while three micro-plots and six plots were installed in the trail area. Generally, the trail area showed greater soil compaction and larger soil surface roughness than the control area. Between October 2015 and September 2016, mean runoff was 500 mm in the control micro-plots and 50% higher in the trail micro-plots. At the plot scale, however, no differences in runoff generation were observed between the two subareas. Sediment production over the same period, however, was twice as high in the trail area than the control area, at both plot scales. In the control area, mean sediment production was 8 Mg ha-1 yr-1 at the micro-plot scale and 6 Mg ha-1 yr-1at the plot scale; in the trail area, these figures were 21 Mg ha-1 yr

Comparison of WEPP and APEX runoff and erosion prediction at field scale in Goodwater Creek Experimental Watershed

USDA-ARS?s Scientific Manuscript database

The Water Erosion Prediction Project (WEPP) and the Agricultural Policy/Environmental eXtender (APEX) are process-based models that can predict spatial and temporal distributions of erosion for hillslopes and watersheds. This study applies the WEPP model to predict runoff and erosion for a 35-ha fie...

Water droplet erosion mechanisms of Ti-6Al-4V

NASA Astrophysics Data System (ADS)

Kamkar Zahmatkesh, Niloofar

Water impingement erosion of materials can be a life-limiting phenomenon for the components in many erosive environments. For example, aircraft body exposed to rain, steam turbine blade, and recently in gas turbine coupled with inlet fogging system. The last is the focus of this study. Inlet fogging system is the most common method used to augment gas turbine output during hot days; high ambient temperature causes strong deterioration of the engine performance. Micro-scaled droplets introduced into the inlet airflow allow the cooling of entering air as well as intercooling the compressor (overspray) and thus optimizes the output power. However, erosion damage of the compressor blades in overspray stage is one of the major concerns associated with the inlet fogging system. The main objective of this research work (CRIAQ MANU419 project) is to understand the erosion induced by water droplets on Titanium alloy to eventually optimize the erosion resistance of the Ti-based compressor blade. Therefore, characterization of the water droplet erosion damage on Ti-6Al-4V receives the major importance. The influence of base material microstructure and impact parameters were considered in erosion evaluation in present study. This work covers the characterization of the erosion damage on Ti-6Al-4V alloy in two parts: - The water droplet erosion damage through a novel experimental approach. The collected data were processed both qualitatively and quantitatively for multi-aspects damage study. - The influence of impact velocity on erosion in an attempt to represent the in-service conditions.

Assessment of the role of bottomland hardwoods in sediment and erosion control

USGS Publications Warehouse

Molinas, A.; Auble, Gregor T.; Segelquist, C.A.; Ischinger, Lee S.

1988-01-01

Drainage and clearing of bottomland hardwoods have long been recognized by the U.S. Environmental Protection Agency (EPA) and the U.S. Fish and Wildlife Service (Service) as important impacts of Federal water projects in the lower Mississippi River Valley. More recently, the water quality impacts of such projects (e.g., increases in sediments, nutrients, and pesticides) have also become of concern. In 1984, in an effort to better define problems concerning wetland losses and water degradation, EPA initiated a cooperative project with the Western Energy and Land Use Team (now the National Ecology Research Center) of the Service. Three phases of the project were identified: 1. To collect existing literature and data; 2. To select, develop, and test the utility of methods to quantify the relationships between land use, cover types, soils, hydrology, and water quality (as represented by sediment); and 3. To apply selected methodologies to several sites within the Yazoo Basin of Mississippi to determine the, potential effectiveness of various management alternatives to reduce sediment yield, increase sediment deposition, and improve water quality. Methods development focused on linking a simulation of water and sediment movement to a computerized geographic information system. We had several objectives for the resulting model. We desired that it should: 1. Estimate the importance of bottomland and hardwoods as a cover type that performs the functions of erosion and sediment control, 2. Simulate effects of proportions of ' various cover types and their specific spatial configurations, 3. Be applicable to moderately large spatial areas with minimal site-specific calibration, 4. Simulate spatial patterns of sediment loss-gain over time, and 5. Represent both sediment detachment and transport. While it was recognized that impacts and management alternatives could be sorted roughly into landscape measures and channel measures, the decision was made to focus study efforts

Use of Sediment Budgets for Watershed Erosion Control Planning: A Case Study From Northern California

NASA Astrophysics Data System (ADS)

O'Connor, M.; McDavitt, W.

2002-05-01

Erosion, sedimentation and peak flow increases caused by forest management for commercial timber production may negatively affect aquatic habitat of endangered anadromous fish such as coho salmon ({\\ it O. kisutch}). This paper summarizes a portion of a Watershed Analysis study performed for Pacific Lumber Company, Scotia, CA, focusing on erosion and sedimentation processes and rates and downstream sediment routing and water quality in the Freshwater Creek watershed in northwest California. Hillslope, road and bank erosion, channel sedimentation and sediment rates were quantified using field surveys, aerial photo interpretation, and empirical modeling approaches for different elements of the study. Sediment transport rates for bedload were modeled, and sediment transport rates for suspended sediment were estimated based on size distribution of sediment inputs in relation to sizes transported in suspension. The resulting sediment budget was validated through comparison using recent short-term, high-quality estimates of suspended sediment yield collected by a community watershed group at a downstream monitoring site with technical assistance from the US Forest Service. Another check on the sediment budget was provided by bedload yield data from an adjacent watershed, Jacoby Creek. The sediment budget techniques and bedload routing models used for this study provide sediment yield estimates that are in good agreement with available data. These results suggest that sediment budget techniques that require moderate levels of fieldwork can be used to provide relatively accurate technical assessments for use in the TMDL process. The sediment budget also identifies the most significant sediment sources and suggests a framework within which effective erosion control strategies can be developed.

Recent and future rainfall erosivity on the territory of the Czech Republic

NASA Astrophysics Data System (ADS)

Krasa, Josef; Stredova, Hana; Stepanek, Petr; Hanel, Martin; Dostal, Tomas; Novotny, Ivan

2015-04-01

Water erosion is a main factor of degradation of soils used for agriculture in the Czech Republic. For landscape conservation purposes the soil erosion risk is defined here mostly by USLE (Wischmeier and Smith, 1978). Within USLE the precipitation impact on erosion is a function of rainfall kinetic energy and intensity represented by R-factor. In the Czech Republic historically and recently several research teams have analyzed rainfall data to assess R-factor. Till now not many European countries have performed detailed spatially distributed analyses of rain erosivities. Most studies use only simplified methods based on long-term rainfall averages or databases of only several station-datasets. The most recent study on rainfall erosivity spatial distribution over the Czech Republic was based on digital rain gauge data from automatic stations of the Czech Hydrometeorogical Institute. The erosive rains were derived from continuous 1 minute step 10-year rainfall data (2003-2012) from 245 stations. Based on the research recent annual R-factor values in the stations vary from 37 to 239 [N.h-1] (values over 100 are located in mountain regions with minimum of agricultural land). Average value is 69 [N.h-1.year-1]. For the Czech Republic the future prediction is based on 10km resolution ALADIN/CZ regional climate model. Within the EU FP6 project CECILIA it was coupled with GCM ARPEGE to provide a projection of future climate in two time slices, 2021-2050 and 2071-2100, according to the IPCC A1B emission scenario. Daily precipitation volumes and percentiles of maximal events allowed authors to develop R-factor maps of present and future scenarios. Based on the analyses we can conclude that average value for the whole territory of the Czech Republic will remain close to 70 [N.h-1.year-1] or even decrease for 2071-2100, but we can expect significant changes (30-40 % rise or decrease) for several large agricultural regions (eg. Southern Moravia). These changes will have impact

Scanning-electron-microscope study of normal-impingement erosion of ductile metals

NASA Technical Reports Server (NTRS)

Brainard, W. A.; Salik, J.

1980-01-01

Scanning electron microscopy was used to characterize the erosion of annealed copper and aluminum surfaces produced by both single- and multiple-particle impacts. Macroscopic 3.2 mm diameter steel balls and microscopic, brittle erodant particles were projected by a gas gun system so as to impact at normal incidence at speeds up to 140 m/sec. During the impacts by the brittle erodant particles, at lower speeds the erosion behavior was similar to that observed for the larger steel balls. At higher velocities, particle fragmentation and the subsequent cutting by the radial wash of debris created a marked change in the erosion mechanism.

Does vegetation prevent wave erosion of salt marsh edges?

PubMed

Feagin, R A; Lozada-Bernard, S M; Ravens, T M; Möller, I; Yeager, K M; Baird, A H

2009-06-23

This study challenges the paradigm that salt marsh plants prevent lateral wave-induced erosion along wetland edges by binding soil with live roots and clarifies the role of vegetation in protecting the coast. In both laboratory flume studies and controlled field experiments, we show that common salt marsh plants do not significantly mitigate the total amount of erosion along a wetland edge. We found that the soil type is the primary variable that influences the lateral erosion rate and although plants do not directly reduce wetland edge erosion, they may do so indirectly via modification of soil parameters. We conclude that coastal vegetation is best-suited to modify and control sedimentary dynamics in response to gradual phenomena like sea-level rise or tidal forces, but is less well-suited to resist punctuated disturbances at the seaward margin of salt marshes, specifically breaking waves.

Cropping and tillage systems effects on soil erosion under climate change in Oklahoma

USDA-ARS?s Scientific Manuscript database

Soil erosion under future climate change is very likely to increase due to projected increases in frequency and magnitude of heavy storms. The objective of this study is to quantify the effects of common cropping and tillage systems on soil erosion and surface runoff during 2010-2039 in central Okl...

Splash erosion. A bibliometric Review

NASA Astrophysics Data System (ADS)

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

Managing dental erosion.

PubMed

Curtis, Donald A; Jayanetti, Jay; Chu, Raymond; Staninec, Michal

2012-01-01

The clinical signs of dental erosion are initially subtle, yet often progress because the patient remains asymptomatic, unaware and uninformed. Erosion typically works synergistically with abrasion and attrition to cause loss of tooth structure, making diagnosis and management complex. The purpose of this article is to outline clinical examples of patients with dental erosion that highlight the strategy of early identification, patient education and conservative restorative management. Dental erosion is defined as the pathologic chronic loss of dental hard tissues as a result of the chemical influence of exogenous or endogenous acids without bacterial involvement. Like caries or periodontal disease, erosion has a multifactorial etiology and requires a thorough history and examination for diagnosis. It also requires patient understanding and compliance for improved outcomes. Erosion can affect the loss of tooth structure in isolation of other cofactors, but most often works in synergy with abrasion and attrition in the loss of tooth structure (Table 1). Although erosion is thought to be an underlying etiology of dentin sensitivity, erosion and loss of tooth structure often occurs with few symptoms. The purpose of this article is threefold: first, to outline existing barriers that may limit early management of dental erosion. Second, to review the clinical assessment required to establish a diagnosis of erosion. And third, to outline clinical examples that review options to restore lost tooth structure. The authors have included illustrations they hope will be used to improve patient understanding and motivation in the early management of dental erosion.

[Erosive petechial gastritis].

PubMed

Llorens, P

1988-01-01

We studied 20 patients in which a variety of erosive gastritis is described. We named it petechial erosive gastritis. We have to bring up that its sequence is due to the presence of the petechiae in the center of the mucosal area. Then in degrees of higher intensity erosions occur also at the center of the area mucosa. Occasionally the erosions meet, become larger and may bleed. An endoscopic classification of petechial erosive gastritis is established it rates mild, moderate, severe and hemorrhagic degrees. Even if the histopathologic study does not keep a strict correspondence with the severity of endoscopic observation of the lesions, it is possible to separate easily a petechial stage from an erosive stage. Demonstration of these lesions at their sequence from petechial to bleeding erosion constitutes an important contribution to the study of acute gastric lesions and it might open a way to a better study of the alterations of the irrigation of the gastric mucosa and the etiology of erosive lesions and acute ulcer.

Field evaluation of support practice (P-factor) for stone walls to control soil erosion in an arid area (Northern Jordan)

NASA Astrophysics Data System (ADS)

Gharaibeh, Mamoun; Albalasmeh, Ammar

2017-04-01

Stone walls have been adopted for long time to control water erosion in many Mediterranean countries. In soil erosion equations, the support practice factor (P-factor) for stone walls has not been fully studied or rarely taken into account especially in semi-arid and arid regions. Field studies were conducted to evaluate the efficiency of traditional stone walls and to quantify soil erosion in six sites in north and northeastern Jordan. Initial estimates using the Universal Soil Loss Equation (USLE) showed that rainfall erosion was reduced by 65% in areas where stone walls are present. Annual soil loss ranged from 5 to 15 t yr-1. The mean annual soil loss in the absence of stone walls ranged from 10-60 t ha-1 with an average value of 35 t ha-1. Interpolating the slope of thickness of A horizon provided an average initial estimate of 0.3 for P value.

Forests and Soil Erosion across Europe

NASA Astrophysics Data System (ADS)

Bathurst, J. C.

2012-04-01

Land use and climate change threaten the ability of Europe's forests to provide a vital service in limiting soil erosion, e.g. from forest fires and landslides. However, our ability to define the threat and to propose mitigation measures suffers from two deficiencies concerning the forest/erosion interface: 1) While there have been a considerable number of field studies of the relationship between forest cover and erosion in different parts of Europe, the data sets are scattered among research groups and a range of literature outlets. There is no comprehensive overview of the forest/erosion interface at the European scale, essential for considering regional variations and investigating the effects of future changes in land use and climate. 2) Compared with forest/water studies, we have a poorer quantitative appreciation of forest/erosion interactions. In the forest/water area it is possible to make quantitative statements such as that a 20% change in forest cover across a river catchment is needed for the effect on annual water yield to be measurable or that a forested catchment in upland UK has an annual water yield around 15% lower than an otherwise comparable grassland catchment. Comparable statements are not yet possible for forest/erosion interactions and there are uncertainties in the mathematical representation of forest/erosion interactions which limit our ability to make predictions, for example of the impact of forest loss in a given area. This presentation therefore considers the next step in improving our predictive capability. It proposes the integration of existing research and data to construct the "big picture" across Europe, i.e. erosion rates and sediment yields associated with forest cover and its loss in a range of erosion regimes (e.g. post-forest fire erosion or post-logging landslides). This would provide a basis for generalizations at the European scale. However, such an overview would not form a predictive capability. Therefore it is also

Erosion of soil organic carbon: implications for carbon sequestration

USGS Publications Warehouse

Van Oost, Kristof; Van Hemelryck, Hendrik; Harden, Jennifer W.; McPherson, B.J.; Sundquist, E.T.

2009-01-01

Agricultural activities have substantially increased rates of soil erosion and deposition, and these processes have a significant impact on carbon (C) mineralization and burial. Here, we present a synthesis of erosion effects on carbon dynamics and discuss the implications of soil erosion for carbon sequestration strategies. We demonstrate that for a range of data-based parameters from the literature, soil erosion results in increased C storage onto land, an effect that is heterogeneous on the landscape and is variable on various timescales. We argue that the magnitude of the erosion term and soil carbon residence time, both strongly influenced by soil management, largely control the strength of the erosion-induced sink. In order to evaluate fully the effects of soil management strategies that promote carbon sequestration, a full carbon account must be made that considers the impact of erosion-enhanced disequilibrium between carbon inputs and decomposition, including effects on net primary productivity and decomposition rates.

WEPPCAT: An Online tool for assessing and managing the potential impacts of climate change on sediment loading to streams using the Water Erosion Prediction Project (WEPP) Model

EPA Science Inventory

WEPPCAT is an on-line tool that provides a flexible capability for creating user-determined climate change scenarios for assessing the potential impacts of climate change on sediment loading to streams using the USDA’s Water Erosion Prediction Project (WEPP) Model. In combination...

Evaluation of erosion and sedimentation associated with tracked vehicle training

Treesearch

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...

Assessment of Spectroscopic, Real-time Ion Thruster Grid Erosion-rate Measurements

NASA Technical Reports Server (NTRS)

Domonkos, Matthew T.; Stevens, Richard E.

2000-01-01

The success of the ion thruster on the Deep Space One mission has opened the gate to the use of primary ion propulsion. Many of the projected planetary missions require throughput and specific impulse beyond those qualified to date. Spectroscopic, real-time ion thruster grid erosion-rate measurements are currently in development at the NASA Glenn Research Center. A preliminary investigation of the emission spectra from an NSTAR derivative thruster with titanium grid was conducted. Some titanium lines were observed in the discharge chamber; however, the signals were too weak to estimate the erosion of the screen grid. Nevertheless, this technique appears to be the only non-intrusive real-time means to evaluate screen grid erosion, and improvement of the collection optics is proposed. Direct examination of the erosion species using laser-induced fluorescence (LIF) was determined to be the best method for a real-time accelerator grid erosion diagnostic. An approach for a quantitative LIF diagnostic was presented.

Does vegetation prevent wave erosion of salt marsh edges?

PubMed Central

Feagin, R. A.; Lozada-Bernard, S. M.; Ravens, T. M.; Möller, I.; Yeager, K. M.; Baird, A. H.

2009-01-01

This study challenges the paradigm that salt marsh plants prevent lateral wave-induced erosion along wetland edges by binding soil with live roots and clarifies the role of vegetation in protecting the coast. In both laboratory flume studies and controlled field experiments, we show that common salt marsh plants do not significantly mitigate the total amount of erosion along a wetland edge. We found that the soil type is the primary variable that influences the lateral erosion rate and although plants do not directly reduce wetland edge erosion, they may do so indirectly via modification of soil parameters. We conclude that coastal vegetation is best-suited to modify and control sedimentary dynamics in response to gradual phenomena like sea-level rise or tidal forces, but is less well-suited to resist punctuated disturbances at the seaward margin of salt marshes, specifically breaking waves. PMID:19509340

Deglaciation and glacial erosion: a joint control on magma productivity by continental unloading

NASA Astrophysics Data System (ADS)

Sternai, Pietro; Caricchi, Luca; Castelltort, Sebastien

2016-04-01

Glacial-interglacial cycles affect the processes through which water and rocks are redistributed across the Earth's surface, thereby linking solid-Earth and climate dynamics. Regional and global scale studies suggest that continental lithospheric unloading due to ice melting during the transition to interglacials leads to increased continental magmatic, volcanic and degassing activity. Such a climatic forcing on the melting of the Earth's interior, however, has always been evaluated without considering the additional continental unloading associated with erosion. Current datasets relating to the evolution of erosion rates are typically limited by temporal resolutions that are too low or span too short time intervals to allow for direct comparisons between the contributions from ice melting and erosion to continental unloading at the timescale of the late Pleistocene glacial cycles. Yet, they provide a fundamental observational basis on which to calibrate numerical predictions. Here, we present and discuss numerical results involving synthetic but realistic topographies, ice caps and glacial erosion rates suggesting that erosion may be as important as deglaciation in affecting continental unloading, sub-continental decompression melting and magma productivity. Thus, the timing and magnitude of deglaciation and erosion must be characterized if the forcing of climate change on the continental magmatic/volcanic activity is to be extracted from the remnants of eroded volcanic centers. Our study represents an additional step towards a more general understanding of the links between a changing climate, glacial processes and the melting of the solid Earth.

Global evaluation of erosion rates in relation to tectonics

NASA Astrophysics Data System (ADS)

Hecht, Hagar; Oguchi, Takashi

2017-12-01

Understanding the mechanisms and controlling factors of erosion rates is essential in order to sufficiently comprehend bigger processes such as landscape evolution. For decades, scientists have been researching erosion rates where one of the main objectives was to find the controlling factors. A variety of parameters have been suggested ranging from climate-related, basin morphometry and the tectonic setting of an area. This study focuses on the latter. We use previously published erosion rate data obtained mainly using 10Be and sediment yield and sediment yield data published by the United States Geological Survey. We correlate these data to tectonic-related factors, i.e., distance to tectonic plate boundary, peak ground acceleration ( PGA), and fault distribution. We also examine the relationship between erosion rate and mean basin slope and find significant correlations of erosion rates with distance to tectonic plate boundary, PGA, and slope. The data are binned into high, medium, and low values of each of these parameters and grouped in all combinations. We find that groups with a combination of high PGA (> 0.2.86 g) and long distance (> 1118.69 km) or low PGA (< 0.68 g) and short distance (< 94.34 km) are almost inexistent suggesting a strong coupling between PGA and distance to tectonic plate boundary. Groups with low erosion rates include long distance and/or low PGA, and groups with high erosion rates include neither of these. These observations indicate that tectonics plays a major role in determining erosion rates, which is partly ascribable to steeper slopes produced by active crustal movements. However, our results show no apparent correlation of slope with erosion rates, pointing to problems with using mean basin-wide slope as a slope indicator because it does not represent the complex slope distribution within a basin.

Reduction of erosive wear in situ by stannous fluoride-containing toothpaste.

PubMed

Huysmans, M C D N J M; Jager, D H J; Ruben, J L; Unk, D E M F; Klijn, C P A H; Vieira, A M

2011-01-01

Stannous fluoride (SnF) has been suggested as a dental erosion-preventive agent. The aim of this single-centre, randomized, double-blind, in situ study was to evaluate the effect of toothpastes with SnF in the prevention of erosive enamel wear. A combined split-mouth (extra-oral water or toothpaste brushing) and crossover (type of toothpaste) set-up was used. Twelve volunteers wore palatal appliances containing human enamel samples. Three toothpastes were used, in three consecutive runs, in randomized order: two toothpastes containing SnF (coded M and PE) and one toothpaste containing only sodium fluoride (coded C). On day 1 of each run the appliances were worn for pellicle formation. On days 2-5 the samples were also brushed twice with a toothpaste-water slurry or only water (control). Erosion took place on days 2-5 extra-orally 3 times a day (5 min) in a citric acid solution (pH 2.3). Enamel wear depth was quantified by optical profilometry. The effect of toothpastes was tested using General Linear Modeling. Average erosive wear depth of control samples was 23 μm. Both SnF toothpastes significantly reduced erosive wear: M by 34% (SD 39%) and PE by 26% (SD 25%). The control toothpaste reduced erosive wear non-significantly by 7% (SD 20%). Both SnF-containing toothpastes significantly reduced erosive wear compared to the sodium fluoride toothpaste. We conclude that SnF-containing toothpastes are able to reduce erosive tooth wear in situ. Copyright © 2011 S. Karger AG, Basel.

Incidence and Pattern of Dental Erosion in Gastroesophageal Reflux Disease Patients.

PubMed

Ramachandran, Anupama; Raja Khan, Sulthan Ibrahim; Vaitheeswaran, Nandinee

2017-11-01

Gastroesophageal reflux disease (GERD) is a very common condition whose consequences of are localized not only in the esophagus; extra-esophageal involvement has frequently been reported. The aim of the study is to examine the incidence and pattern of dental erosion in GERD patients. A total of 50 patients were recruited in this study (control -25 and GERD -25). All participants diagnosed having GERD by the endoscopic examination by their gastroenterologist are included. The patients were examined for dental erosion and will be quantified using Basic erosive wear examination index. The results showed that the incidence of dental erosion was 88% as compared to 32% in the control group which was found to be statistically significant.

Ecosystem services in Mediterranean river basin: climate change impact on water provisioning and erosion control.

PubMed

Bangash, Rubab F; Passuello, Ana; Sanchez-Canales, María; Terrado, Marta; López, Alfredo; Elorza, F Javier; Ziv, Guy; Acuña, Vicenç; Schuhmacher, Marta

2013-08-01

The Mediterranean basin is considered one of the most vulnerable regions of the world to climate change and such changes impact the capacity of ecosystems to provide goods and services to human society. The predicted future scenarios for this region present an increased frequency of floods and extended droughts, especially at the Iberian Peninsula. This paper evaluates the impacts of climate change on the water provisioning and erosion control services in the densely populated Mediterranean Llobregat river basin of. The assessment of ecosystem services and their mapping at the basin scale identify the current pressures on the river basin including the source area in the Pyrenees Mountains. Drinking water provisioning is expected to decrease between 3 and 49%, while total hydropower production will decrease between 5 and 43%. Erosion control will be reduced by up to 23%, indicating that costs for dredging the reservoirs as well as for treating drinking water will also increase. Based on these data, the concept for an appropriate quantification and related spatial visualization of ecosystem service is elaborated and discussed. Copyright © 2013 Elsevier B.V. All rights reserved.

Lincoln Park shoreline erosion control project: Monitoring for surface substrate, infaunal bivalves and eelgrass, 1993

DOE Office of Scientific and Technical Information (OSTI.GOV)

Antrim, L.D.; Thom, R.M.; Gardiner, W.W.

1993-09-01

In 1988, the US Army Corps of Engineers and the City of Seattle placed material on the upper beach at Lincoln Park, in West Seattle, Washington. The fill served to mitigate shoreline erosion that had caused undercutting and collapse of the seawall in several places. A series of pre- and post-construction studies have been conducted to assess the impacts to marine biota of fill placement and movement of surface substrate. This study was designed to monitor infaunal bivalves and eelgrass from intertidal areas in and adjacent to the area of original fill placement. Findings from this survey were compared tomore » previous survey results to determine (1) if recruitment of infaunal bivalves to the fill area has occurred, (2) if infaunal bivalve densities outside the fill area are stable, and (3) if eelgrass distribution and abundance have remained stable along the adjacent shoreline. To maximize comparability of findings from this survey with previous studies, sampling techniques, transects, and tidal elevations were consistent with previous studies at this site.« less

Factors controlling volume errors through 2D gully erosion assessment: guidelines for optimal survey design

NASA Astrophysics Data System (ADS)

Castillo, Carlos; Pérez, Rafael

2017-04-01

The assessment of gully erosion volumes is essential for the quantification of soil losses derived from this relevant degradation process. Traditionally, 2D and 3D approaches has been applied for this purpose (Casalí et al., 2006). Although innovative 3D approaches have recently been proposed for gully volume quantification, a renewed interest can be found in literature regarding the useful information that cross-section analysis still provides in gully erosion research. Moreover, the application of methods based on 2D approaches can be the most cost-effective approach in many situations such as preliminary studies with low accuracy requirements or surveys under time or budget constraints. The main aim of this work is to examine the key factors controlling volume error variability in 2D gully assessment by means of a stochastic experiment involving a Monte Carlo analysis over synthetic gully profiles in order to 1) contribute to a better understanding of the drivers and magnitude of gully erosion 2D-surveys uncertainty and 2) provide guidelines for optimal survey designs. Owing to the stochastic properties of error generation in 2D volume assessment, a statistical approach was followed to generate a large and significant set of gully reach configurations to evaluate quantitatively the influence of the main factors controlling the uncertainty of the volume assessment. For this purpose, a simulation algorithm in Matlab® code was written, involving the following stages: - Generation of synthetic gully area profiles with different degrees of complexity (characterized by the cross-section variability) - Simulation of field measurements characterised by a survey intensity and the precision of the measurement method - Quantification of the volume error uncertainty as a function of the key factors In this communication we will present the relationships between volume error and the studied factors and propose guidelines for 2D field surveys based on the minimal survey

Soil erosion in developing countries: A politicoeconomic explanation

NASA Astrophysics Data System (ADS)

Thapa, Gopal B.; Weber, Karl E.

1991-07-01

Soil erosion is accelerating in developing countries of Asia, Africa, and Latin America. It has threatened the livelihood of millions of peasants, for agriculture is their economic mainstay. A probe into the forces causing erosion reveals that the elite’s resolve to accumulate ever more wealth and to maintain, consolidate, or expand their sociopolitical power and the necessity of the poor to fulfill their requirements of food, fuelwood, and fodder are the two major factors accelerating soil erosion. Unless the vast masses of poor people are integrated into the national mainstream through the implementation of equitable and redistributive development policies, it is impossible to control the accelerating rate of soil erosion and thus to achieve the objective of sustainable development.

Reduction of Gun Erosion and Correlation of Gun Erosion Measurements

NASA Technical Reports Server (NTRS)

Bogdanoff, Dave; Wercinski, Paul (Technical Monitor)

1997-01-01

Gun barrel erosion is serious problem with two-stage light gas guns. Excessive barrel erosion can lead to poor or failed launches and frequent barrel changes, with the corresponding down time. Also, excessive barrel erosion can limit the maximum velocity obtainable by loading down the hydrogen working gas with eroded barrel material. Guided by a CFD code, the operating conditions of the Ames 0.5-inch gun were modified to reduce barrel erosion. The changes implemented included: (1) reduction in the piston mass, powder mass and hydrogen fill pressure; and (2) reduction in pump tube volume, while maintaining hydrogen mass. The latter change was found, in particular, to greatly reduce barrel erosion. For muzzle velocity ranges of 6.1 - 6.9 km/sec, the barrel erosion was reduced by a factor of 10. Even for the higher muzzle velocity range of 7.0 - 8.2 km/sec, the barrel erosion was reduced by a factor of 4. Gun erosion data from the Ames 0.5-inch, 1.0-inch, and 1.5-inch guns operated over a wide variety of launch conditions was examined and it was found that this data could be correlated using four different parameters: normalized powder charge energy, normalized hydrogen energy density, normalized pump tube volume and barrel diameter. The development of the correlation and the steps used to collapse the experimental data are presented. Over a certain parameter range in the correlation developed, the barrel erosion per shot is found to increase very rapidly. The correlation should prove useful in the selection of gun operating conditions and the design of new guns. Representative shapes of eroded gun barrels are also presented.

Rice straw mulch for post-fire erosion control: assessing non-target effects on vegetation communities

Treesearch

Kristen L. Shive; Becky L. Estes; Angela M. White; Hugh D. Safford; Kevin L. O' Hara; Scott L. Stephens

2017-01-01

Straw mulch is commonly used for post-fire erosion control in severely burned areas but this practice can introduce non-native species, even when certified weed-free straw is used. Rice straw has recently been promoted as an alternative to wheat under the hypothesis that non-native species that are able to grow in a rice field are unlikely to establish in dry forested...

Effects of cropping and tillage systems on soil erosion under climate change in Oklahoma

USDA-ARS?s Scientific Manuscript database

Soil erosion under future climate change is very likely to increase due to projected increases in frequency and magnitude of heavy storms. The objective of this study is to quantify the effects of common cropping and tillage systems on soil erosion and surface runoff during 2010-2039 in central Okl...

Detailed Project Report and Environmental Assessment. Section 111. Shores East of Diked Disposal Area, Lorain Harbor, Ohio.

DTIC Science & Technology

1981-11-01

STONE). &7 LAB 07 AORD LAB APRL 1978 LAB * 107/78.6118 PRESQUE ISLE PROJECT UNK ORD LAB CLEVELAND WEST BREAKWATER JU. LAB 103/78.6240 .R..ABILITATION...NOTES IS. KEY WORDS (Continue on revere side if neeemvr and identify by block number) beach erosion diked disposal areas shore erosion Lake Erie ...House Document No. 229, 83rd Congress, "Appendix VIII, Ohio Shoreline of Lake Erie Between Vermilion and Sheffield Lake Village, Beach Erosion Control

Monsoonal versus Anthropogenic Controls on Erosion Patterns and Sediment Flux in the Song Gianh, Vietnam

NASA Astrophysics Data System (ADS)

Clift, Peter; Jonell, Tara; Carter, Andrew; Van Hoang, Long; Böning, Philipp

2016-04-01

The Song Gianh is a small drainage on the northern central coast of Vietnam that delivers sediment into the Gulf of Tonkin. The basin provides the opportunity to evaluate what surface processes control continental erosion rates and patterns because there is a strong monsoonal precipitation gradient from the SW to NE. We apply several complimentary provenance methods to modern siliciclastic sediments of the Song Gianh to pinpoint regions of focused sediment generation and evaluate how sediment is mixed downstream and delivered to the ocean. We find that detrital zircon populations of Song Gianh main channel change radically downstream of the confluence with the northern Rao Tro tributary, which is dominated by 100-300 Ma grains eroded from granite bedrock. This tributary provides almost as much zircon to the main channel as all the headwater tributaries combined, despite being a much smaller, drier, and flatter sub-basin. In contrast, bulk sediment Nd and Sr isotopes indicate that most sediment is derived from the wetter headwater tributaries. Contribution from the southern tributaries to the net siliciclastic river flux is negligible. Precipitation and topography do not appear to modulate zircon production in the modern river although regions controlling bulk Nd and Sr compositions are wetter and have higher local relief. This apparent contrast in regions of sediment production suggests disequilibrium and differential travel times for zircon and mineral phases rich in Nd and Sr. Optically Stimulated Luminescence (OSL) dating of alluvial terraces on the main channel show that the valleys aggraded rapidly from ~7-9 ka during a period of strong summer monsoon, suggesting that heavy rainfall generated large sediment volumes. Younger terraces dated to 500-1000 yrs BP are interpreted to reflect erosion and aggradation driven by extensive human agriculture. We speculate that agriculture, together with bedrock compositions, are the most likely control on producing the

The Water Erosion Prediction Project (WEPP) model for saturation excess conditions: application to an agricultural and a forested watershed.

NASA Astrophysics Data System (ADS)

Crabtree, B.; Brooks, E.; Ostrowski, K.; Elliot, W. J.; Boll, J.

2006-12-01

We incorporated saturation excess overland flow processes in the Water Erosion Prediction Project (WEPP) model for the evaluation of human disturbances in watersheds. In this presentation, we present results of the modified WEPP model to two watersheds: an agricultural watershed with mixed land use, and a forested watershed. The agricultural watershed is Paradise Creek, an intensively monitored watershed with continuous climate, flow and sediment data collection at multiple locations. Restoration efforts in Paradise Creek watershed include changing to minimal tillage or no-tillage sytems, and implementation of structural practices. The forested watershed is the 28 km2 Mica Creek Experimental Watershed (MCEW) where disturbances include clear and partial cutting, and road building. The MCEW has a nested study design, which allows for the analysis of cumulative effects as well as the traditional comparison of treatment versus control. Mica Creek watershed is a high elevation watershed where streamflow is generated mostly by snowmelt. Treatments include road building in 1997, and clearcut and partial-cut logging in 2001. Our results include the simulation of streamflow and sediment delivery at multiple locations within each watershed, and evaluation of the human disturbances.

Graffiti for science - erosion painting reveals spatially variable erosivity of sediment-laden flows

NASA Astrophysics Data System (ADS)

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.

Erosion Potential of Tooth Whitening Regimens as Evaluated with Polarized Light Microscopy.

PubMed

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 < 0.0001). Mean enamel 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 < 0.0001]. There was no significant difference between the negative control and each of treatment groups (p > 0.05 for all instances), except for Natural White_10 times treatment group (p < 0.0001) that was significantly greater than the negative control group (14.82 vs 2.65 μm). Caution is advised when

Improving ground cover monitoring for wind erosion assessment using MODIS BRDF parameters

USDA-ARS?s Scientific Manuscript database

Measuring and monitoring controls on wind erosion can facilitate detection and prediction of soil degradation important for food security. Ground cover is widely recognised as an important factor for controlling soil erosion by wind and water. Consequently, maintaining ground cover (e.g., vegetation...

Comparison of Erosion Rates Estimated by Sediment Budget Techniques and Suspended Sediment Monitoring and Regulatory Implications

NASA Astrophysics Data System (ADS)

O'Connor, M.; Eads, R.

2007-12-01

Watersheds in the northern California Coast Range have been designated as "impaired" with respect to water quality because of excessive sediment loads and/or high water temperature. Sediment budget techniques have typically been used by regulatory authorities to estimate current erosion rates and to develop targets for future desired erosion rates. This study examines erosion rates estimated by various methods for portions of the Gualala River watershed, designated as having water quality impaired by sediment under provisions of the Clean Water Act Section 303(d), located in northwest Sonoma County (~90 miles north of San Francisco). The watershed is underlain by Jurassic age sedimentary and meta-sedimentary rocks of the Franciscan formation. The San Andreas Fault passes through the western edge of watershed, and other active faults are present. A substantial portion of the watershed is mantled by rock slides and earth flows, many of which are considered dormant. The Coast Range is geologically young, and rapid rates of uplift are believed to have contributed to high erosion rates. This study compares quantitative erosion rate estimates developed at different spatial and temporal scales. It is motivated by a proposed vineyard development project in the watershed, and the need to document conditions in the project area, assess project environmental impacts and meet regulatory requirements pertaining to water quality. Erosion rate estimates were previously developed using sediment budget techniques for relatively large drainage areas (~100 to 1,000 km2) by the North Coast Regional Water Quality Control Board and US EPA and by the California Geological Survey. In this study, similar sediment budget techniques were used for smaller watersheds (~3 to 8 km2), and were supplemented by a suspended sediment monitoring program utilizing Turbidity Threshold Sampling techniques (as described in a companion study in this session). The duration of the monitoring program to date

Regionalization of monthly rainfall erosivity patternsin Switzerland

NASA Astrophysics Data System (ADS)

Schmidt, Simon; Alewell, Christine; Panagos, Panos; Meusburger, Katrin

2016-10-01

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 proportion

A study on the erosion of Niigata Beach from ERTS-A imagery

NASA Technical Reports Server (NTRS)

Maruyasu, T.

1973-01-01

Coastal erosion of Niigata Beach, Japan as a result of construction works is discussed. The application of ERTS-1 imagery for defining and monitoring the extent of the erosion is described. The contribution of ERTS-1 data to studies leading to effective erosion control methods are reported.

Determination of riverbank erosion probability using Locally Weighted Logistic Regression

NASA Astrophysics Data System (ADS)

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.

Compost for steep slope erosion.

DOT National Transportation Integrated Search

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)...

Issues of upscaling in space and time with soil erosion models

NASA Astrophysics Data System (ADS)

Brazier, R. E.; Parsons, A. J.; Wainwright, J.; Hutton, C.

2009-04-01

Soil erosion - the entrainment, transport and deposition of soil particles - is an important phenomenon to understand; the quantity of soil loss determines the long term on-site sustainability of agricultural production (Pimental et al., 1995), and has potentially important off-site impacts on water quality (Bilotta and Brazier, 2008). The fundamental mechanisms of the soil erosion process have been studied at the laboratory scale, plot scale (Wainwright et al., 2000), the small catchment scale (refs here) and river basin scale through sediment yield and budgeting work. Subsequently, soil erosion models have developed alongside and directly from this empirical work, from data-based models such as the USLE (Wischmeier and Smith, 1978), to ‘physics or process-based' models such as EUROSEM (Morgan et al., 1998) and WEPP (Nearing et al., 1989). Model development has helped to structure our understanding of the fundamental factors that control soil erosion process at the plot and field scale. Despite these advances, however, our understanding of and ability to predict erosion and sediment yield at the same plot, field and also larger catchment scales remains poor. Sediment yield has been shown to both increase and decrease as a function of drainage area (de Vente et al., 2006); the lack of a simple relationship demonstrates complex and scale-dependant process domination throughout a catchment, and emphasises our uncertainty and poor conceptual basis for predicting plot to catchment scale erosion rates and sediment yields (Parsons et al., 2006b). Therefore, this paper presents a review of the problems associated with modelling soil erosion across spatial and temporal scales and suggests some potential solutions to address these problems. The transport-distance approach to scaling erosion rates (Wainwright, et al., 2008) is assessed and discussed in light of alternative techniques to predict erosion across spatial and temporal scales. References Bilotta, G.S. and

Mechanics of interrill erosion with wind-driven rain

USDA-ARS?s Scientific Manuscript database

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...

Evaluating soil erodibility dynamics to improve estimates of wind erosion in drylands

USDA-ARS?s Scientific Manuscript database

Wind erosion is a key driver of land degradation in the world’s drylands. Soil loss and nutrient decline due to wind erosion increase the sensitivity of drylands to climate stressors. Better understanding the factors controlling wind erosion in drylands will provide a basis for identifying and testi...

Estimating erosion in a riverine watershed: Bayou Liberty-Tchefuncta River in Louisiana.

PubMed

Martin, August; Gunter, James T; Regens, James L

2003-01-01

GOAL, SCOPE, BACKGROUND: Sheet erosion from agricultural, forest and urban lands may increase stream sediment loads as well as transport other pollutants that adversely affect water quality, reduce agricultural and forest production, and increase infrastructure maintenance costs. This study uses spatial analysis techniques and a numerical modeling approach to predict areas with the greatest sheet erosion potential given different soils disturbance scenarios. A Geographic Information System (GIS) and the Universal Soil Loss Equation (USLE) were used to estimate sheet erosion from 0.64 ha parcels of land within the watershed. The Soil Survey of St. Tammany Parish, Louisiana was digitized, required soil attributes entered into the GIS database, and slope factors determined for each 80 x 80 meter parcel in the watershed. The GIS/USLE model used series-specific erosion K factors, a rainfall factor of 89, and a GIS database of scenario-driven cropping and erosion control practice factors to estimate potential soil loss due to sheet erosion. A general trend of increased potential sheet erosion occurred for all land use categories (urban, agriculture/grasslands, forests) as soil disturbance increases from cropping, logging and construction activities. Modeling indicated that rapidly growing urban areas have the greatest potential for sheet erosion. Evergreen and mixed forests (production forest) had lower sheet erosion potentials; with deciduous forests (mostly riparian) having the least sheet erosion potential. Erosion estimates from construction activities may be overestimated because of the value chosen for the erosion control practice factor. This study illustrates the ease with which GIS can be integrated with the Universal Soil Loss Equation to identify areas with high sheet erosion potential for large scale management and policy decision making. The GIS/USLE modeling approach used in this study offers a quick and inexpensive tool for estimating sheet erosion within

Change Analysis on Soil Erosion of Fujian Province from 1990 TO 2015

NASA Astrophysics Data System (ADS)

Wang, X. Q.; Zeng, S. J.; Chen, X. G.; Lin, J. L.; Chen, S. M.

2017-09-01

Soil erosion is one of major environment problems in the world, and China is one of the most serious soil erosion country. In this paper, Fujian province was used as a study area for its typical red soil region. Based on USLE model, the soil erosion modulus in 1990 and 2015 were calculated and turned to soil erosion intensity. The soil erosion distribution trend in Fujian province was decrease from south-east coastal zone to north-west inland region. In soil erosion areas, the main erosion type was light level with about 80 %, and the soil erosion levels above serious type were mainly sporadic distribution with less than 10 %. The soil erosion improved for the past 25 years. The areas of different erosion types all decreased, and the total erosion area reduced by 26.59 %. The improvement area mainly located in north-east, south and west region. The aggravation area mainly located in the north and some middle hilly regions. The impact of human activities is more significant for erosion control.

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

ERIC Educational Resources Information Center

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.…

What can we learn from national-scale geodata describing soil erosion?

NASA Astrophysics Data System (ADS)

Benaud, Pia; Anderson, Karen; Carvalho, Jason; Evans, Martin; Glendell, Miriam; James, Mike; Lark, Murray; Quine, Timothy; Quinton, John; Rawlins, Barry; Rickson, Jane; Truckell, Ian; Brazier, Richard

2017-04-01

The United Kingdom has a rich dataset of soil erosion observations, which have been collected using a wide range of methodologies, across various spatial and temporal scales. Yet, while observations of soil erosion have been carried out along-side agricultural development and intensification, understanding whether or not the UK has a soil erosion problem remains a question to be answered. Furthermore, although good reviews of existing soil erosion rates exist, there is no single resource that brings all of this work together. Therefore, the primary aim of this research was to build a picture of why attempts to quantify erosion rates across the UK empirically have fallen short, through: (1) Collating all available, UK-based and empirically-derived soil erosion datasets into a spatially explicit and open-access database, (2) Developing an understanding of observed magnitudes of erosion, in the UK, (3) Evaluating impact of non-environmental controls on erosion observations i.e. study methodologies, and (4) Exploring trends between environmental controls and erosion rates. To-date, the database holds over 1500 records, which include results from both experimental and natural conditions, across arable, grassland and upland environments. Of the studies contained in the database, erosion has been observed ca. 40% of instances, ranging from <0.01 t.ha-1.yr-1 to 143 t.ha-1.yr-1. However, preliminary analysis has highlighted that over 90% of the studies included in the database only quantify soil loss via visible erosion features, such as rills or gullies, through volumetric assessments. Furthermore, there has been an inherent bias in the UK towards quantifying soil erosion in locations with either a known history or high probability of erosion occurrence. As a consequence, we conclude that such databases, may not be used to make a statistically unbiased assessment of national-scale erosion rates, however, they can highlight maximum likely rates under a wide range of soil

Anacardic acid from brazilian cashew nut trees reduces dentine erosion.

PubMed

Silveira, Cintia; Oliveira, Flávia; Dos Santos, Maria Lucilia; de Freitas, Thiago; Imparato, José Carlos; Magalhães, Ana Carolina

2014-01-01

The aim of this study was to analyze the effect of solutions containing saturated anacardic acid (AA) on dentine erosion in vitro. AA was chemically isolated from natural cashew nutshell liquid obtained by continuous extraction in a Soxhlet extractor and was fully saturated by catalytic hydrogenation. Matrix metalloproteinase 2 (MMP-2) activity, when exposed to buffers containing 100 µmol/l AA, was analyzed using zymography. Bovine root samples were subjected to erosive demineralization (Sprite Zero™, 4 × 90 s/day) and remineralization with artificial saliva between the erosive cycles for 5 days. The samples were treated as follows, after the first and the last acid exposure (1 min; n = 12/group): (1) 100 µmol/l epigallocatechin-3-gallate (EGCG) (positive control); (2) 0.05% NaF; (3) 100 µmol/l saturated AA; (4) saturated AA and EGCG; (5) saturated AA, EGCG and NaF; (6) untreated (negative control). Dentine erosion was measured using a contact profilometer. Two dentine samples from each group were analyzed using scanning electron microscopy. Saturated AA reduced the activity of MMP-2. ANOVA and Tukey's test revealed that all treatments significantly reduced dentine loss compared to the negative control (6.03 ± 0.98 µm). Solutions containing saturated AA (1.97 ± 1.02 µm) showed the greatest reduction in dentine erosion compared to the NaF (3.93 ± 1.54 µm) and EGCG (3.79 ± 0.83 µm) solutions. Therefore, it may be concluded that AA significantly reduces dentine erosion in vitro, possibly by acting as an MMP-2 inhibitor.

Preventive Effect of CPP-ACPF Paste and Fluoride Toothpastes Against Erosion and Erosion Plus Abrasion 
In Vitro - A 3D Profilometric Analysis.

PubMed

Soares, Genaina Guimarães; Magalhães, Pâmela Amorim; Fonseca, Ana Beatriz Monteiro; Tostes, Monica Almeida; Silva, Eduardo Moreira da; Coutinho, Thereza Christina Lopes

To evaluate the effect of CPP-ACPF paste and fluoride toothpastes on enamel subjected to erosion and erosion plus abrasion in vitro. A total of 220 human enamel blocks were divided into eleven groups (n = 20): CPP-ACPF paste (MPP), potassium nitrate/sodium fluoride toothpaste (PE), sodium fluoride toothpaste (FD), fluoride-free toothpaste (SO) and control (erosion only with no paste or toothpastes; CO) according to the experimental design: erosion or erosion plus abrasion immediately after erosion (ERO+I-ABR) or 30 min after erosion (ERO+30min-ABR). For 5 days, the specimens were subjected to: (1) erosive challenge (EC) (cola drink, 4 x 5 min/day), topical application of the undiluted paste or diluted toothpastes (1:2 w/w) (4 x 1 min/ day) plus 1 h in artificial saliva (AS) between cycles and overnight; or (2) EC plus abrasion (4 x /60 s/day) performed with the diluted toothpastes (no MMP) plus 1 h in AS between cycles and overnight. Erosion depth was quantified through a 3D profilometer. Data were analysed using Kruskal-Wallis, Mann-Whitney and Wilcoxon tests (p = 0.05). CPP-ACPF paste and NaF toothpaste showed lowest enamel wear among groups and reduced tissue loss by 89% in erosion challenge. Abrasion led to higher enamel wear than erosion only (p = 0.030). ERO+30min-ABR had no protective effect when compared to ERO+I-ABR (p > 0.05). A high frequency of CPP-ACPF paste application (4x daily) is effective in reducing the effects of erosion. A waiting period before performing toothbrushing does not protect enamel against erosion regardless the composition of the toothpastes.

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

USDA-ARS?s Scientific Manuscript database

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...

Influence of gully erosion control on amphibian and reptile communities within riparian zones of channelized streams

USDA-ARS?s Scientific Manuscript database

Riparian zones of streams in northern Mississippi have been impacted by agriculture, channelization, channel incision, and gully erosion. Gully erosion is the most severe form of erosion and has resulted in the fragmentation of remnant riparian zones within agricultural watersheds. One widely used c...

Adaptation of rhizome connections in drylands: increasing tolerance of clones to wind erosion.

PubMed

Yu, Fei-Hai; Wang, Ning; He, Wei-Ming; Chu, Yu; Dong, Ming

2008-10-01

Wind erosion is a severe stress for plants in drylands, but the mechanisms by which plants withstand erosion remain largely unknown. Here, the hypothesis is tested that maintaining rhizome connections helps plants to tolerate erosion. Five transects were established across an inland dune in Inner Mongolia, China, and measurements were made of leaf number, biomass per ramet and rhizome depth of Psammochloa villosa in 45 plots. In 40 x 40 cm plots of P. villosa on another dune, the top 15 or 30 cm of sand was removed for 1.5 or 3 months to simulate short- and long-term moderate and severe erosion, respectively, with untreated plots as controls, and the rhizomes at the edges of half of the plots were severed to mimic loss of rhizome connections. Leaf number and biomass per ramet showed quadric relationships with rhizome depth; when rhizomes were exposed to the air, the associated ramets either died or became very weak. Ramet number, leaf number and biomass per plot decreased with increasing erosion severity. Rhizome connections did not affect these traits under control or short-term erosion, but increased them under long-term erosion. Rhizome connections alleviated the negative effects of erosion on P. villosa, very likely because the erosion-stressed ramets received water and/or photosynthates translocated from those connected ramets that were not subject to erosion. This study provides the first evidence that maintaining rhizome connections helps plants to tolerate erosion in drylands.

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

USGS Publications Warehouse

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

2018-01-01

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.

NASA's Evolutionary Xenon Thruster (NEXT) Project Qualification Propellant Throughput Milestone: Performance, Erosion, and Thruster Service Life Prediction After 450 kg

NASA Technical Reports Server (NTRS)

Herman, Daniel A.

2010-01-01

The NASA s Evolutionary Xenon Thruster (NEXT) program is tasked with significantly improving and extending the capabilities of current state-of-the-art NSTAR thruster. The service life capability of the NEXT ion thruster is being assessed by thruster wear test and life-modeling of critical thruster components, such as the ion optics and cathodes. The NEXT Long-Duration Test (LDT) was initiated to validate and qualify the NEXT thruster propellant throughput capability. The NEXT thruster completed the primary goal of the LDT; namely to demonstrate the project qualification throughput of 450 kg by the end of calendar year 2009. The NEXT LDT has demonstrated 28,500 hr of operation and processed 466 kg of xenon throughput--more than double the throughput demonstrated by the NSTAR flight-spare. Thruster performance changes have been consistent with a priori predictions. Thruster erosion has been minimal and consistent with the thruster service life assessment, which predicts the first failure mode at greater than 750 kg throughput. The life-limiting failure mode for NEXT is predicted to be loss of structural integrity of the accelerator grid due to erosion by charge-exchange ions.

Erosion resistant coatings

NASA Technical Reports Server (NTRS)

Falco, L.; Cushini, A.

1981-01-01

Apparatus for measuring the resistance of materials to erosion is examined and a scheme for standardization of the test parameters is described. Current materials being used for protecting aircraft parts from erosion are surveyed, their chief characteristics being given. The superior properties of urethane coatings are pointed out. The complete cycle for painting areas subject to erosion is described.

How does slope form affect erosion in CATFLOW-SED?

NASA Astrophysics Data System (ADS)

Gabelmann, Petra; Wienhöfer, Jan; Zehe, Erwin

2016-04-01

Erosion is a severe environmental problem in agro-ecosystems with highly erodible loess soils. It is controlled by various factors, e.g. rainfall intensity, initial wetness conditions, soil type, land use and tillage practice. Furthermore slope form and gradient have been shown to influence erosion amounts to a large extent. Within the last fifty years, various erosion models have been developed to describe the erosion process, estimate erosion amounts and identify erosion-prone areas. These models differ in terms of complexity, the processes which are considered, and the data required for model calibration and they can be categorised into empirical or statistical, conceptual, and physically-based models. CATFLOW-SED is a process-based hydrology and erosion model that can operate on catchment and hillslope scales. Soil water dynamics are described by the Richards equation including effective approaches for preferential flow. Evapotranspiration is simulated using an approach based on the Penman-Monteith equation. The model simulates overland flow using the diffusion wave equation. Soil detachment is related to the attacking forces of rainfall and overland flow, and the erosion resistance of soil. Sediment transport capacity and sediment deposition are related to overland flow velocity using the equation of Engelund and Hansen and the sinking velocity of grain sizes respectively. We performed a study to analyse the erosion process on different virtual hillslopes, with varying slope gradient and slope form, using the CATFLOW-SED model. We explored the role of landform on erosion and sedimentation, particularly we look for forms that either maximise or minimise erosion. Results indicate the importance to performing the process implementation within physically meaningful limits and choose appropriate model parameters respectively.

Predicting of soil erosion with regarding to rainfall erosivity and soil erodibility

NASA Astrophysics Data System (ADS)

Suif, Zuliziana; Razak, Mohd Amirun Anis Ab; Ahmad, Nordila

2018-02-01

The soil along the hill and slope are wearing away due to erosion and it can take place due to occurrence of weak and heavy rainfall. The aim of this study is to predict the soil erosion degree in Universiti Pertahanan Nasional Malaysia (UPNM) area focused on two major factor which is soil erodibility and rainfall erosivity. Soil erodibility is the possibilities of soil to detach and carried away during rainfall and runoff. The "ROM" scale was used in this study to determine the degree of soil erodibility, namely low, moderate, high, and very high. As for rainfall erosivity, the erosive power caused by rainfall that cause soil loss. A daily rainfall data collected from January to April was analyzed by using ROSE index classification to identify the potential risk of soil erosion. The result shows that the soil erodibilty are moderate at MTD`s hill, high at behind of block Lestari and Landslide MTD hill, and critical at behind the mess cadet. While, the highest rainfall erosivity was recorded in March and April. Overall, this study would benefit the organization greatly in saving cost in landslide protection as relevant authorities can take early measures repairing the most affected area of soil erosion.

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

Treesearch

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....

Climate change impact on soil erosion in the Mandakini River Basin, North India

NASA Astrophysics Data System (ADS)

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.

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

Treesearch

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...

Erosion distribution in Central Nepal Himalaya from late Pleistocene to present : evidence for recent anthropic forcing of erosion of the Lesser Himalaya

NASA Astrophysics Data System (ADS)

France-Lanord, C.; Lave, J.; Morin, G. P.; Gajurel, A.; Galy, A.; Bosia, C.; Sinha, R.

2016-12-01

Evolution of the erosion of continental surfaces through geologic times provides key evidences to assess the interplay of controls exerted by tectonic, topography, climate, and lately, human activities. Mountains belts, and particularly the Himalaya, present intense tectonic activity, contrasted seasonality marked by the monsoon, steep topography and recent socio-economic development, which makes it a laboratory to assess main issues on these complex interactions.Taking advantage of the large Sr and Nd isotopic contrasts of the main geological and physiographic Himalayan units, this study explores the time variations of the spatial distribution of erosion in Central Nepal Himalaya. Compiling Sr and Nd isotopic compositions of rivers sediments from many tributaries within the Narayani Basin in central Nepal, we first define the mean Sr and Nd isotopic compositions of the three main Himalayan geological units in this region. Then, we present isotopic chronicles of river sediments sampled at the outlet of the Narayani Basin during 21 years, and 50-kyr-long sedimentary archives drilled in the foreland basin.Using Sr and Nd isotopic compositions to trace relative geological provenances and contributions, we show that erosion distribution in the Narayani Basin remained stable for 50 kyr until the end of the 20th century. Sediment fluxes were primarily derived from erosion of the High Himalayan regions (Tethys H. and HHC) ( 80 %), i.e. from the areas presenting high reliefs and steep slopes. Erosion distribution stability during the Pleistocene-Holocene climatic transition provides new evidence for a primary control of erosion by tectonic forcing rather than climatic forcing in the Himalayas. Since 2000s, a shift of the sediment isotopic compositions reveals an intensification of erosion in the Lesser Himalaya (from 15-25% to 30-45% of the sediment budget) despite unchanged tectonic or climatic conditions. We propose that this strong increase by 2-3 fold of erosion of the

Distinguishing between tectonic and lithologic controls on bedrock channel longitudinal profiles using cosmogenic 10Be erosion rates and channel steepness index

USGS Publications Warehouse

Cyr, Andrew J.; Granger, Darryl E.; Olivetti, Valerio; Molin, Paola

2014-01-01

Knickpoints in fluvial channel longitudinal profiles and channel steepness index values derived from digital elevation data can be used to detect tectonic structures and infer spatial patterns of uplift. However, changes in lithologic resistance to channel incision can also influence the morphology of longitudinal profiles. We compare the spatial patterns of both channel steepness index and cosmogenic 10Be-determined erosion rates from four landscapes in Italy, where the geology and tectonics are well constrained, to four theoretical predictions of channel morphologies, which can be interpreted as the result of primarily tectonic or lithologic controls. These data indicate that longitudinal profile forms controlled by unsteady or nonuniform tectonics can be distinguished from those controlled by nonuniform lithologic resistance. In each landscape the distribution of channel steepness index and erosion rates is consistent with model predictions and demonstrates that cosmogenic nuclide methods can be applied to distinguish between these two controlling factors.

Susceptibility of bovine dental enamel with initial erosion lesion to new erosive challenges

PubMed Central

Tereza, Guida Paola Genovez; Boteon, Ana Paula; Ferrairo, Brunna Mota; Gonçalves, Priscilla Santana Pinto; da Silva, Thiago Cruvinel; Honório, Heitor Marques; Rios, Daniela

2017-01-01

This in vitro study evaluated the impact of initial erosion on the susceptibility of enamel to further erosive challenge. Thirty bovine enamel blocks were selected by surface hardness and randomized into two groups (n = 15): GC- group composed by enamel blocks without erosion lesion and GT- group composed by enamel blocks with initial erosion lesion. The baseline profile of each block was determined using the profilometer. The initial erosion was produced by immersing the blocks into HCl 0.01 M, pH 2.3 for 30 seconds, under stirring. The erosive cycling consisted of blocks immersion in hydrochloric acid (0.01 M, pH 2.3) for 2 minutes, followed by immersion in artificial saliva for 120 minutes. This procedure was repeated 4 times a day for 5 days, and the blocks were kept in artificial saliva overnight. After erosive cycling, final profile measurement was performed. Profilometry measured the enamel loss by the superposition of initial and final profiles. Data were analyzed by t-test (p<0.05). The result showed no statistically significant difference between groups (GS = 14.60±2.86 and GE = .14.69±2.21 μm). The presence of initial erosion on bovine dental enamel does not enhance its susceptibility to new erosive challenges. PMID:28817591

Susceptibility of bovine dental enamel with initial erosion lesion to new erosive challenges.

PubMed

Oliveira, Gabriela Cristina de; Tereza, Guida Paola Genovez; Boteon, Ana Paula; Ferrairo, Brunna Mota; Gonçalves, Priscilla Santana Pinto; Silva, Thiago Cruvinel da; Honório, Heitor Marques; Rios, Daniela

2017-01-01

This in vitro study evaluated the impact of initial erosion on the susceptibility of enamel to further erosive challenge. Thirty bovine enamel blocks were selected by surface hardness and randomized into two groups (n = 15): GC- group composed by enamel blocks without erosion lesion and GT- group composed by enamel blocks with initial erosion lesion. The baseline profile of each block was determined using the profilometer. The initial erosion was produced by immersing the blocks into HCl 0.01 M, pH 2.3 for 30 seconds, under stirring. The erosive cycling consisted of blocks immersion in hydrochloric acid (0.01 M, pH 2.3) for 2 minutes, followed by immersion in artificial saliva for 120 minutes. This procedure was repeated 4 times a day for 5 days, and the blocks were kept in artificial saliva overnight. After erosive cycling, final profile measurement was performed. Profilometry measured the enamel loss by the superposition of initial and final profiles. Data were analyzed by t-test (p<0.05). The result showed no statistically significant difference between groups (GS = 14.60±2.86 and GE = .14.69±2.21 μm). The presence of initial erosion on bovine dental enamel does not enhance its susceptibility to new erosive challenges.

Morphological characterization of microspheres, films and implants prepared from poly(lactide-co-glycolide) and ABA triblock copolymers: is the erosion controlled by degradation, swelling or diffusion?

PubMed

Witt, C; Kissel, T

2001-05-01

Erosion of biodegradable parenteral delivery systems (PDS) based on ABA copolymers consisting of poly(L-lactide-co-glycolide) (PLGA) A-blocks attached to polyethylene oxide (PEO) B-blocks, or PLGA is important for the release of macromolecular drugs. The degradation behavior of four types of PDS, namely extruded rods, tablets, films and microspheres, was studied with respect to molecular weight, mass, polymer composition and shape and microstructure of the PDS. For each device the onset time of bulk erosion (t(on)) and the apparent rate of mass loss (k(app)) were calculated. In the case of PLGA, the t(on) was 16.2 days for microspheres, 19.2 days for films and 30.1 days for cylindrical implants and tablets. The k(app) was 0.04 days(-1) for microspheres, 0.09 days(-1) for films, 0.11 days(-1) for implants and 0.10 days(-1) for tablets. The degradation rates were in the same range irrespective of the geometry and the micrographs of eroding PDS demonstrated pore formation; therefore, a complex pore diffusion mechanism seems to control the erosion of PLGA devices. In contrast, PDS based on ABA copolymers showed swelling, followed by a parallel process of molecular weight degradation and polymer erosion, independent of the geometry. The contact angles of ABA films increased either with decreasing PEO content or with increasing chain length of the PEO B-blocks. In summary, the insertion of a hydrophilic B-block leads to an erosion controlled by degradation of ABA copolymers, whereas for PLGA a complex pore diffusion of degradation products controls the rate of bulk erosion.

Statistics of rocky coast erosion and percolation theory

NASA Astrophysics Data System (ADS)

Baldassarri, A.; Sapoval, B.

2012-04-01

The dynamics of rocky coasts is an erratic phenomenon featuring numerous small erosion events, but sometimes large dramatic collapses. In this sense, its study should not limit or rely on average erosion rates. Recent studies, based on historical as well as recent data, have indicated that the frequency of magnitude of erosion events display long tail distribution, similar to what observed in landslide. In other words the time evolution of a coast morphology does not enter the classical category of Gaussian process, but rather that of critical systems in physics. We recently proposed a minimal dynamical model of rocky coast erosion which is able to reproduce the diversity of rocky coast morphologies and their dynamics. This model is based on a single, simple ingredient, the retroaction of the coast morphology on the erosive power of the sea. It follows from the idea that erosion can spontaneously create irregular seashores, but, in turn, the geometrical irregularity of the coast participates to the damping of sea-waves, decreasing the average wave amplitude and erosive power. The resulting mutual self-stabilization dynamics of the sea erosion power and coastal irregular morphology leads spontaneously the system to a critical dynamics. Our results indicate then that rocky coast erosion and the statistical theory of percolation are closely related. In this framework, the sometimes fractal geometry of coastlines can be recovered and understood in terms of fractal dimension of the external perimeter of a percolation cluster. From a more practical point of view, the analogy with percolation interfaces means that the coast constitutes a strong, but possibly fragile, barrier to sea erosion, emerging from a self-organised selection process. Accordingly, the effect of a slow weathering degradation of the rocks mechanical properties, as well as other perturbations from natural or human cause, can trigger random and large erosion events difficult to predict and control. To

Soil erosion under multiple time-varying rainfall events

NASA Astrophysics Data System (ADS)

Heng, B. C. Peter; Barry, D. Andrew; Jomaa, Seifeddine; Sander, Graham C.

2010-05-01

Soil erosion is a function of many factors and process interactions. An erosion event produces changes in surface soil properties such as texture and hydraulic conductivity. These changes in turn alter the erosion response to subsequent events. Laboratory-scale soil erosion studies have typically focused on single independent rainfall events with constant rainfall intensities. This study investigates the effect of multiple time-varying rainfall events on soil erosion using the EPFL erosion flume. The rainfall simulator comprises ten Veejet nozzles mounted on oscillating bars 3 m above a 6 m × 2 m flume. Spray from the nozzles is applied onto the soil surface in sweeps; rainfall intensity is thus controlled by varying the sweeping frequency. Freshly-prepared soil with a uniform slope was subjected to five rainfall events at daily intervals. In each 3-h event, rainfall intensity was ramped up linearly to a maximum of 60 mm/h and then stepped down to zero. Runoff samples were collected and analysed for particle size distribution (PSD) as well as total sediment concentration. We investigate whether there is a hysteretic relationship between sediment concentration and discharge within each event and how this relationship changes from event to event. Trends in the PSD of the eroded sediment are discussed and correlated with changes in sediment concentration. Close-up imagery of the soil surface following each event highlight changes in surface soil structure with time. This study enhances our understanding of erosion processes in the field, with corresponding implications for soil erosion modelling.

Irrigation: Erosion

USDA-ARS?s Scientific Manuscript database

Irrigation is essential for global food production. However, irrigation erosion can limit the ability of irrigation systems to reliably produce food and fiber in the future. The factors affecting soil erosion from irrigation are the same as rainfall—water detaches and transports sediment. However, t...

Erosion-Resistant Nanocoatings for Improved Energy Efficiency in Gas Turbine Engines

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2009-06-01

This factsheet describes a research project whose goal is to test and substantiate erosion-resistant (ER) nanocoatings for application on compressor airfoils for gas turbine engines in both industrial gas turbines and commercial aviation.

Plant biodiversity effects in reducing fluvial erosion are limited to low species richness.

PubMed

Allen, Daniel C; Cardinale, Bradley J; Wynn-Thompson, Theresa

2016-01-01

It has been proposed that plant biodiversity may increase the erosion resistance of soils, yet direct evidence for any such relationship is lacking. We conducted a mesocosm experiment with eight species of riparian herbaceous plants, and found evidence that plant biodiversity significantly reduced fluvial erosion rates, with the eight-species polyculture decreasing erosion by 23% relative to monocultures. Species richness effects were largest at low levels of species richness, with little increase between four and eight species. Our results suggest that plant biodiversity reduced erosion rates indirectly through positive effects on root length and number of root tips, and that interactions between legumes and non-legumes were particularly important in producing biodiversity effects. Presumably, legumes increased root production of non-legumes by increasing soil nitrogen availability due to their ability to fix atmospheric nitrogen. Our data suggest that a restoration project using species from different functional groups might provide the best insurance to maintain long-term erosion resistance.

Adaptation of Rhizome Connections in Drylands: Increasing Tolerance of Clones to Wind Erosion

PubMed Central

Yu, Fei-Hai; Wang, Ning; He, Wei-Ming; Chu, Yu; Dong, Ming

2008-01-01

Background and Aims Wind erosion is a severe stress for plants in drylands, but the mechanisms by which plants withstand erosion remain largely unknown. Here, the hypothesis is tested that maintaining rhizome connections helps plants to tolerate erosion. Methods Five transects were established across an inland dune in Inner Mongolia, China, and measurements were made of leaf number, biomass per ramet and rhizome depth of Psammochloa villosa in 45 plots. In 40 × 40 cm plots of P. villosa on another dune, the top 15 or 30 cm of sand was removed for 1·5 or 3 months to simulate short- and long-term moderate and severe erosion, respectively, with untreated plots as controls, and the rhizomes at the edges of half of the plots were severed to mimic loss of rhizome connections. Key Results Leaf number and biomass per ramet showed quadric relationships with rhizome depth; when rhizomes were exposed to the air, the associated ramets either died or became very weak. Ramet number, leaf number and biomass per plot decreased with increasing erosion severity. Rhizome connections did not affect these traits under control or short-term erosion, but increased them under long-term erosion. Conclusions Rhizome connections alleviated the negative effects of erosion on P. villosa, very likely because the erosion-stressed ramets received water and/or photosynthates translocated from those connected ramets that were not subject to erosion. This study provides the first evidence that maintaining rhizome connections helps plants to tolerate erosion in drylands. PMID:18621966

An holistic approach to beach erosion vulnerability assessment.

PubMed

Alexandrakis, George; Poulos, Serafim Ε

2014-08-15

Erosion is a major threat for coasts worldwide, beaches in particular, which constitute one of the most valuable coastal landforms. Vulnerability assessments related to beach erosion may contribute to planning measures to counteract erosion by identifying, quantifying and ranking vulnerability. Herein, we present a new index, the Beach Vulnerability Index (BVI), which combines simplicity in calculations, easily obtainable data and low processing capacity. This approach provides results not only for different beaches, but also for different sectors of the same beach and enables the identification of the relative significance of the processes involved. It functions through the numerical approximation of indicators that correspond to the mechanisms related to the processes that control beach evolution, such as sediment availability, wave climate, beach morhodynamics and sea level change. The BVI is also intended to be used as a managerial tool for beach sustainability, including resilience to climate change impact on beach erosion.

Climate, wildfire, and erosion ensemble foretells more sediment in western USA watersheds

USGS Publications Warehouse

Sankey, Joel B.; Kreitler, Jason R.; Hawbaker, Todd; McVay, Jason L.; Miller, Mary Ellen; Mueller, Erich R.; Vaillant, Nicole M.; Lowe, Scott E.; Sankey, Temuulen T.

2017-01-01

The area burned annually by wildfires is expected to increase worldwide due to climate change. Burned areas increase soil erosion rates within watersheds, which can increase sedimentation in downstream rivers and reservoirs. However, which watersheds will be impacted by future wildfires is largely unknown. Using an ensemble of climate, fire, and erosion models, we show that post-fire sedimentation is projected to increase for nearly nine-tenths of watersheds by > 10% and for more than one-third of watersheds by > 100% by the 2041 to 2050 decade in the western USA. The projected increases are statistically significant for more than eight-tenths of the watersheds. In the western USA, many human communities rely on water from rivers and reservoirs that originates in watersheds where sedimentation is projected to increase. Increased sedimentation could negatively impact water supply and quality for some communities, in addition to affecting stream channel stability and aquatic ecosystems.

Longitudinal study of gastroesophageal reflux and erosive tooth wear.

PubMed

Wilder-Smith, Clive H; Materna, Andrea; Martig, Lukas; Lussi, Adrian

2017-10-25

Approximately 60% of patients presenting to dentists with erosive tooth wear have significant gastroesophageal reflux (GERD), despite minor reflux symptoms. No longitudinal studies of reflux-associated erosive tooth wear and of reflux characteristics have been reported to date. The aim of this study was to characterize the longitudinal course of GERD and of associated erosive tooth wear, as well as factors predictive of its progression, in a large group of patients. Seventy-two patients presenting to dentists with clinically significant erosive tooth wear and increased esophageal acid exposure by 24-h multichannel intraluminal pH-impedance measurement (MII-pH) were re-assessed clinically and by MII-pH after 1 year treatment with esomeprazole 20 mg twice-daily. Predictive factors for erosive tooth wear were assessed by logistic regression. At follow-up, no further progression in erosive tooth wear was observed in 53 (74%) of patients. The percentage of time with a pH < 4, the number of acid reflux episodes and the percentage of proximal esophageal reflux off-PPI did not change significantly after one year, but the number of weakly acidic reflux episodes decreased significantly in the large subgroup without progression. None of the baseline demographic, clinical, endoscopic or esophageal acid exposure characteristics were significantly associated with progression of erosive tooth wear at follow-up. In this longitudinal study in patients with erosive tooth wear and oligosymptomatic GERD receiving esomeprazole for one year, erosive tooth wear did not progress further in the majority of patients. Background acidic esophageal reflux exposure appeared stable over time, whereas weakly acidic exposure decreased significantly in patients without erosion progression. MII-pH measurements on-PPI and with healthy controls will be useful in the further elucidation of the causal role of reflux in erosive tooth wear. ClinicalTrials.gov , retrospectively registered: NCT02087345 .

Evaluating the efficacy of wood shreds for mitigating erosion

Treesearch

Randy B. Foltz; Natalie S. Copeland

2009-01-01

An erosion control product made by shredding on-site woody materials was evaluated for mitigating erosion through a series of rainfall simulations. Tests were conducted on bare soil and soil with 30, 50, and 70% cover on a coarse and a fine-grained soil. Results indicated that the wood product known as wood shreds reduced runoff and soil loss from both soil types....

Project resources planning and control

NASA Technical Reports Server (NTRS)

Sibbers, C. W.

1984-01-01

This report contains instructional guidelines for the resources planning and control of research and development (R&D) projects managed by NASA's Langley Research Center (LaRC). Although written to serve primarily as a practical guide and reference for those LaRC personnel who perform resources planning, analysis, control, and reporting functions, it should also be meaningful to other NASA personnel who are directly or indirectly involved in or affected by these functions, especially project technical managers whose responsibilities include resources management. Certain sections should help Contractor personnel to better understand what resources information must usually be submitted on LaRC projects and what use is made of such information. The Project Manager of a large R&D project typicaly receives support from an Analyst in the area of resources management. The Analyst provides assistance in four functional areas: Planning, Analysis/Control, Administration, and Reporting. Each of these functions are discussed in detail. Examples of techniques used effectively on LaRC projects have been included where applicable. A considerable amount of information has been included on the use of Performance Measurement (Earned Value) Systems for contract cost control and reporting as little information is currently available on this subject in NASA publications.

Effect of chemical and mechanical weed control on cassava yield, soil quality and erosion under cassava cropping system

NASA Astrophysics Data System (ADS)

Islami, Titiek; Wisnubroto, Erwin; Utomo, Wani

2016-04-01

Three years field experiments were conducted to study the effect of chemical and mechanical weed control on soil quality and erosion under cassava cropping system. The experiment were conducted at University Brawijaya field experimental station, Jatikerto, Malang, Indonesia. The experiments were carried out from 2011 - 2014. The treatments consist of three cropping system (cassava mono culture; cassava + maize intercropping and cassava + peanut intercropping), and two weed control method (chemical and mechanical methods). The experimental result showed that the yield of cassava first year and second year did not influenced by weed control method and cropping system. However, the third year yield of cassava was influence by weed control method and cropping system. The cassava yield planted in cassava + maize intercropping system with chemical weed control methods was only 24 t/ha, which lower compared to other treatments, even with that of the same cropping system used mechanical weed control. The highest cassava yield in third year was obtained by cassava + peanuts cropping system with mechanical weed control method. After three years experiment, the soil of cassava monoculture system with chemical weed control method possessed the lowest soil organic matter, and soil aggregate stability. During three years of cropping soil erosion in chemical weed control method, especially on cassava monoculture, was higher compared to mechanical weed control method. The soil loss from chemical control method were 40 t/ha, 44 t/ha and 54 t/ha for the first, second and third year crop. The soil loss from mechanical weed control method for the same years was: 36 t/ha, 36 t/ha and 38 t/ha. Key words: herbicide, intercropping, soil organic matter, aggregate stability.

Runoff and initial erosion assessment in fruit tree crops and improved forage pastures in the slopes of the Irazu Volcano (Costa Rica)

NASA Astrophysics Data System (ADS)

Marchamalo, Miguel; González-Rodrigo, Beatriz

2017-04-01

Costa Rica is located in the Central American tropical isthmus. It presents high precipitations (ranging from 1400-8500 mm) and protection levels (27% of national territory). However, intensive land use and increasing population in headwaters are major threats for water resource management in this country. Birrís Basin is a 4800 hectares sub-watershed of the River Reventazón Basin, the major hydroelectric source in Costa Rica. Birrís Basin was selected for its high estimated erosion rates and its potential for demonstrative projects (ICE, 1999). Some pilot projects have been developed in this watershed starting from 1999, when major Costa Rican energy producer, Instituto Costarricense de Electricidad, began with a long term watershed management program for the Reventazón Basin. This study aims at measuring runoff and initial splash and sheet erosion to assess the hydrological response of two pilot land use projects. Erosion and runoff plots were established and monitored in a one year period for two pilot projects (fruit trees and forage pastures) and their respective traditional land uses (vegetable crops and extensive pastures). Improved forage pastures showed reduced runoff by 73% and split erosion by 55% compared to prior extensive pastures. Conversion of vegetable crop lands into fruit tree plantations (apricot and avocado) made possible a 97% reduction of soil initial erosion. Land use pilot projects have succeeded in runoff and soil erosion reduction. Now it is time for a wider technology transfer program to expand improved land uses within Birrís Basin.

Testing the Control of Mineral Supply Rates on Chemical Erosion Rates in the Klamath Mountains

NASA Astrophysics Data System (ADS)

West, N.; Ferrier, K.

2016-12-01

The relationship between rates of chemical erosion and mineral supply is central to many problems in Earth science, including how tightly Earth's climate should be coupled to tectonics, how strongly nutrient supply to soils and streams depends on soil production, and how much lithology affects landscape evolution. Despite widespread interest in this relationship, there remains no consensus on how closely coupled chemical erosion rates should be to mineral supply rates. To address this, we have established a network of field sites in the Klamath Mountains along a latitudinal transect that spans an expected gradient in mineral supply rates associated with the geodynamic response to the migration of the Mendocino Triple Junction. Here, we present new measurements of regolith geochemistry and topographic analyses that will be compared with cosmogenic 10Be measurements to test hypotheses about supply-limited and kinetically-limited chemical erosion on granodioritic ridgetops. Previous studies in this area suggest a balance between rock uplift rates and basin wide erosion rates, implying the study ridgetops may have adjusted to an approximate steady state. Preliminary data are consistent with a decrease in chemical depletion fraction (CDF) with increasing ridgetop curvature. To the extent that ridgetop curvature reflects ridgetop erosion rates, this implies that chemical erosion rates at these sites are influenced by both mineral supply rates and dissolution kinetics.

Soil tillage conservation and its effect on erosion control, water management and carbon sequestration

NASA Astrophysics Data System (ADS)

Rusu, T.; Gus, P.; Bogdan, I.; Moraru, P.; Pop, A.; Clapa, D.; Pop, L.

2009-04-01

fuel for preparing the germination bed. Presently it is necessary a change concerning the concept of conservation practices and a new approach regarding the control of erosion. The real conservation of soil must be expanded beyond the traditional understanding of soil erosion. The real soil conservation is represented by carbon management. We need to focus to another level concerning conservation by focusing on of soil quality. Carbon management is necessary for a complex of matters including soil, water management, field productivity, biological fuel and climatic change.

Estimation of regional differences in wind erosion sensitivity in Hungary

NASA Astrophysics Data System (ADS)

Mezősi, G.; Blanka, V.; Bata, T.; Kovács, F.; Meyer, B.

2015-01-01

In Hungary, wind erosion is one of the most serious natural hazards. Spatial and temporal variation in the factors that determine the location and intensity of wind erosion damage are not well known, nor are the regional and local sensitivities to erosion. Because of methodological challenges, no multi-factor, regional wind erosion sensitivity map is available for Hungary. The aim of this study was to develop a method to estimate the regional differences in wind erosion sensitivity and exposure in Hungary. Wind erosion sensitivity was modelled using the key factors of soil sensitivity, vegetation cover and wind erodibility as proxies. These factors were first estimated separately by factor sensitivity maps and later combined by fuzzy logic into a regional-scale wind erosion sensitivity map. Large areas were evaluated by using publicly available data sets of remotely sensed vegetation information, soil maps and meteorological data on wind speed. The resulting estimates were verified by field studies and examining the economic losses from wind erosion as compensated by the state insurance company. The spatial resolution of the resulting sensitivity map is suitable for regional applications, as identifying sensitive areas is the foundation for diverse land development control measures and implementing management activities.

Buhne Point Shoreline Erosion Demonstration Project. Volume 1. Appendices A-D.

DTIC Science & Technology

1987-08-01

for repairing damage to highways and preventing damage to highways resulting from shoreline erosion." A four- year , four-phase program was implemented...program included experimental collecting and growing of 20 different native and naturalized species for a two- year period, and then extensive...King Salmon forming a bay side boundary between the shoal area and King Salmon. Over the past decade, Buhne Spit shoal has eroded to the point where

Relations between rainfall–runoff-induced erosion and aeolian deposition at archaeological sites in a semi-arid dam-controlled river corridor

USGS Publications Warehouse

Collins, Brian D.; Bedford, David; Corbett, Skye C.; Fairley, Helen C.; Cronkite-Ratcliff, Collin

2016-01-01

Process dynamics in fluvial-based dryland environments are highly complex with fluvial, aeolian, and alluvial processes all contributing to landscape change. When anthropogenic activities such as dam-building affect fluvial processes, the complexity in local response can be further increased by flood- and sediment-limiting flows. Understanding these complexities is key to predicting landscape behavior in drylands and has important scientific and management implications, including for studies related to paleoclimatology, landscape ecology evolution, and archaeological site context and preservation. Here we use multi-temporal LiDAR surveys, local weather data, and geomorphological observations to identify trends in site change throughout the 446-km-long semi-arid Colorado River corridor in Grand Canyon, Arizona, USA, where archaeological site degradation related to the effects of upstream dam operation is a concern. Using several site case studies, we show the range of landscape responses that might be expected from concomitant occurrence of dam-controlled fluvial sand bar deposition, aeolian sand transport, and rainfall-induced erosion. Empirical rainfall-erosion threshold analyses coupled with a numerical rainfall–runoff–soil erosion model indicate that infiltration-excess overland flow and gullying govern large-scale (centimeter- to decimeter-scale) landscape changes, but that aeolian deposition can in some cases mitigate gully erosion. Whereas threshold analyses identify the normalized rainfall intensity (defined as the ratio of rainfall intensity to hydraulic conductivity) as the primary factor governing hydrologic-driven erosion, assessment of false positives and false negatives in the dataset highlight topographic slope as the next most important parameter governing site response. Analysis of 4+ years of high resolution (four-minute) weather data and 75+ years of low resolution (daily) climate records indicates that dryland erosion is dependent on short

Erosion by an Alpine glacier.

PubMed

Herman, Frédéric; Beyssac, Olivier; Brughelli, Mattia; Lane, Stuart N; Leprince, Sébastien; Adatte, Thierry; Lin, Jiao Y Y; Avouac, Jean-Philippe; Cox, Simon C

2015-10-09

Assessing the impact of glaciation on Earth's surface requires understanding glacial erosion processes. Developing erosion theories is challenging because of the complex nature of the erosion processes and the difficulty of examining the ice/bedrock interface of contemporary glaciers. We demonstrate that the glacial erosion rate is proportional to the ice-sliding velocity squared, by quantifying spatial variations in ice-sliding velocity and the erosion rate of a fast-flowing Alpine glacier. The nonlinear behavior implies a high erosion sensitivity to small variations in topographic slope and precipitation. A nonlinear rate law suggests that abrasion may dominate over other erosion processes in fast-flowing glaciers. It may also explain the wide range of observed glacial erosion rates and, in part, the impact of glaciation on mountainous landscapes during the past few million years. Copyright © 2015, American Association for the Advancement of Science.

The Significance of Land Cover Delineation on Soil Erosion Assessment.

PubMed

Efthimiou, Nikolaos; Psomiadis, Emmanouil

2018-04-25

The study aims to evaluate the significance of land cover delineation on soil erosion assessment. To that end, RUSLE (Revised Universal Soil Loss Equation) was implemented at the Upper Acheloos River catchment, Western Central Greece, annually and multi-annually for the period 1965-92. The model estimates soil erosion as the linear product of six factors (R, K, LS, C, and P) considering the catchment's climatic, pedological, topographic, land cover, and anthropogenic characteristics, respectively. The C factor was estimated using six alternative land use delineations of different resolution, namely the CORINE Land Cover (CLC) project (2000, 2012 versions) (1:100,000), a land use map conducted by the Greek National Agricultural Research Foundation (NAGREF) (1:20,000), a land use map conducted by the Greek Payment and Control Agency for Guidance and Guarantee Community Aid (PCAGGCA) (1:5,000), and the Landsat 8 16-day Normalized Difference Vegetation Index (NDVI) dataset (30 m/pixel) (two approximations) based on remote sensing data (satellite image acquired on 07/09/2016) (1:40,000). Since all other factors remain unchanged per each RUSLE application, the differences among the yielded results are attributed to the C factor (thus the land cover pattern) variations. Validation was made considering the convergence between simulated (modeled) and observed sediment yield. The latter was estimated based on field measurements conducted by the Greek PPC (Public Power Corporation). The model performed best at both time scales using the Landsat 8 (Eq. 13) dataset, characterized by a detailed resolution and a satisfactory categorization, allowing the identification of the most susceptible to erosion areas.

Does Canoeing Increase Streambank Erosion?

Treesearch

Edward A. Hansen

1975-01-01

Describes research on the Pine River in Michigan to determine if large increases in canoeing accelerated streambank erosion. Most erosion was natural, but people sliding and camping on streambanks created some erosion. Heavy canoe traffic was not a cause of erosion.

Epic Erosion Along Newly Constructed Roads in Yunnan, China

NASA Astrophysics Data System (ADS)

Sidle, R. C.; Kono, Y.; Yamaguchi, T.

2007-05-01

The recent expansion and construction of new mountain roads in northwestern Yunnan Province, China, poses problems related to landslides and surface erosion that are impacting the headwaters of three great river systems: the Salween, Mekong, and Yangtze. Many of these newer roads are simply blasted into unstable hillsides with virtually no attention paid to optimal road location, construction practices, and erosion control measures. During summer 2006, seven people traveling in a minivan along a newly constructed road to Weixi were killed by a landslide. A survey conducted along a this 23.5 km road section (4 yr old) in the headwaters of the Mekong River revealed epic levels of landslides and surface erosion. Based on a preliminary survey, the road erosion was categorized as moderately severe, severe, or very severe, and a representative 0.75 to 0.90 km stretch of road was then surveyed for both landslide (based on dimensional analysis) and surface erosion (based on soil pedestal height). Average mass wasting rates (9608 t ha-1yr-1) along the road were more than 13 times higher than surface erosion (720 t ha-1yr-1), even though surface erosion rates are among the highest reported for disturbed lands. Dry ravel constituted a minor proportion of the mass wasting: 4% in the severe erosion section of the road and 0.5-0.6% in the moderately severe and very severe sections. For the very severe erosion road section (6 km long), estimated landslide erosion alone was > 33,000 t ha- 1yr-1, 620 times the average landslide erosion from forest roads built in unstable terrain in western North America. These levels of landslide erosion along the Weixi road are the highest ever documented and are somewhat representative of erosion along new mountain roads in this region of Yunnan. Sediment produced from roads is highly connected to fluvial systems; we estimate that 80-95% of the direct sediment contributions into the headwaters of these rivers are attributable to road erosion and

Fire effects on rangeland hydrology and erosion in a steep sagebrush-dominated landscape

Treesearch

Frederick B. Pierson; Peter R. Robichaud; Corey A. Moffet; Kenneth E. Spaeth; Stuart P. Hardegree; Patrick E. Clark; C. Jason Williams

2008-01-01

Post-fire runoff and erosion from wildlands has been well researched, but few studies have researched the degree of control exerted by fire on rangeland hydrology and erosion processes. Furthermore, the spatial continuity and temporal persistence of wildfire impacts on rangeland hydrology and erosion are not well understood. Small-plot rainfall and concentrated flow...

winderosionnetwork.org – Portal to the National Wind Erosion Research Network

USDA-ARS?s Scientific Manuscript database

The National Wind Erosion Research Network was established in 2014 as a collaborative effort led by the USDA Agricultural Research Service and Natural Resources Conservation Service, and USDI Bureau of Land Management, to address the need for standardized measurements of wind erosion and its control...

Illuminating wildfire erosion and deposition patterns with repeat terrestrial lidar

USGS Publications Warehouse

Rengers, Francis K.; Tucker, G.E.; Moody, J.A.; Ebel, Brian

2016-01-01

Erosion following a wildfire is much greater than background erosion in forests because of wildfire-induced changes to soil erodibility and water infiltration. While many previous studies have documented post-wildfire erosion with point and small plot-scale measurements, the spatial distribution of post-fire erosion patterns at the watershed scale remains largely unexplored. In this study lidar surveys were collected periodically in a small, first-order drainage basin over a period of 2 years following a wildfire. The study site was relatively steep with slopes ranging from 17° to > 30°. During the study period, several different types of rain storms occurred on the site including low-intensity frontal storms (2.4 mm h−1) and high-intensity convective thunderstorms (79 mm h−1). These storms were the dominant drivers of erosion. Erosion resulting from dry ravel and debris flows was notably absent at the site. Successive lidar surveys were subtracted from one another to obtain digital maps of topographic change between surveys. The results show an evolution in geomorphic response, such that the erosional response after rain storms was strongly influenced by the previous erosional events and pre-fire site morphology. Hillslope and channel roughness increased over time, and the watershed armored as coarse cobbles and boulders were exposed. The erosional response was spatially nonuniform; shallow erosion from hillslopes (87% of the study area) contributed 3 times more sediment volume than erosion from convergent areas (13% of the study area). However, the total normalized erosion depth (volume/area) was highest in convergent areas. From a detailed understanding of the spatial locations of erosion, we made inferences regarding the processes driving erosion. It appears that hillslope erosion is controlled by rain splash (for detachment) and overland flow (for transport and quasi-channelized erosion), with the sites of highest erosion corresponding to locations

Investigation of erosion behavior in different pipe-fitting using Eulerian-Lagrangian approach

NASA Astrophysics Data System (ADS)

Kulkarni, Harshwardhan; Khadamkar, Hrushikesh; Mathpati, Channamallikarjun

2017-11-01

Erosion is a wear mechanism of piping system in which wall thinning occurs because of turbulent flow along with along with impact of solid particle on the pipe wall, because of this pipe ruptures causes costly repair of plant and personal injuries. In this study two way coupled Eulerian-Lagrangian approach is used to solve the liquid solid (water-ferrous suspension) flow in the different pipe fitting namely elbow, t-junction, reducer, orifice and 50% open gate valve. Simulations carried out using incomressible transient solver in OpenFOAM for different Reynolds's number (10k, 25k, 50k) and using WenYu drag model to find out possible higher erosion region in pipe fitting. Used transient solver is a hybrid in nature which is combination of Lagrangian library and pimpleFoam. Result obtained from simulation shows that exit region of elbow specially downstream of straight, extradose of the bend section more affected by erosion. Centrifugal force on solid particle at bend affect the erosion behavior. In case of t-junction erosion occurs below the locus of the projection of branch pipe on the wall. For the case of reducer, orifice and a gate valve reduction area as well as downstream is getting more affected by erosion because of increase in velocities.

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

PubMed

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 (<6 t ha(-1) year(-1)) and, in 20% of the catchment, the 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.

PREDICTING MINESOIL EROSION POTENTIAL

EPA Science Inventory

Two experimental plots were instrumented with erosion pins to study the correspondence between point erosion and erosion over an area on strip mine soil. Using a rotating boom rainfall simulator, data were collected by sampling the runoff every five minutes for the duration of th...

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

PubMed

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.

The interaction between soil erosion and soil organisms in temperate agroecosystems: nematode redistribution in tramlines

NASA Astrophysics Data System (ADS)

Baxter, Craig; Rowan, John S.; McKenzie, Blair M.; Neilson, Roy

2014-05-01

Arable agriculture presents a unique set of challenges, and one of the most important is soil erosion. Whilst policy and practice look towards sustainable intensification of production to ensure food security, fundamental gaps in our understanding still exist. The physical processes involved in the detachment, transport and deposition of soil are well characterised but further research considering chemical and nutrient transport, fertiliser and pesticide losses, and environmental impacts to downstream environments is still required. Furthermore the interaction between soil erosion and soil organisms have largely been ignored, even though soil organisms serve a myriad of functions essential in the provision of soil ecosystem goods and services. Here we present the findings of a field-scale experiment into soil biotic redistribution undertaken at the James Hutton Institute's Balruddery Farm, Scotland (Link Tramlines Project XDW8001). Farm vehicle-tyre wheelings left in arable fields (tramlines) to enable crop spraying during the crop growth cycle have been identified as key transport pathways for sediment and associated nutrients. We tested the hypothesis that soil organisms were also transported by tramline erosion. During the winter of 2012/13 an experiment was undertaken to measure soil organism export from unbound hillslope plots subject to four different tramline treatments set out in a randomised block design. We used soil nematodes as a model organism as they are ubiquitous and sensitive to disturbance and an established indicator taxa of biological and physico-chemical changes in soil. Tramline treatments included a control tyre (conventional tractor tyre), a control tyre with a sown tramline, a low pressure tyre with sown tramline, and a control tyre with a spiked harrow. Post-event sampling of rainfall events was undertaken, and a range of variables measured in the laboratory. The spiked harrow treatment produced the greatest overall reductions in nematode

Mediterranean Agricultural Soil Conservation under global Change: The MASCC project.

NASA Astrophysics Data System (ADS)

Raclot, Damien; Ciampalini, Rossano

2017-04-01

The MASCC project (2016-2019, http://mascc-project.org) aims to address mitigation and adaptation strategies to global change by assessing current and future development of Mediterranean agricultural soil vulnerability to erosion in relation to projected land use, agricultural practices and climate change. It targets to i) assess the similarities/dissimilarities in dominant factors affecting the current Mediterranean agricultural soil vulnerability by exploring a wide range of Mediterranean contexts; ii) improve the ability to evaluate the impact of extreme events on both the current and projected agricultural soil vulnerability and the sediment delivery at catchment outlet; iii) evaluate the vulnerability and resilience of agricultural production to a combination of potential changes in a wide range of Mediterranean contexts, iv) and provide guidelines on sustainable agricultural conservation strategies adapted to each specific agro-ecosystem and taking into consideration both on- and off-site erosion effects and socio-economics issues. To achieve these objectives, the MASCC project consortium gather researchers from six Mediterranean countries (France, Morocco, Tunisia, Italy, Spain and Portugal) which monitor mid- to long-term environmental catchments and benefit from mutual knowledge created from previous projects and network. The major assets for MASCC are: i) the availability of an unrivalled database on catchment soil erosion and innovative agricultural practices comprising a wide range of Mediterranean contexts, ii) the capacity to better evaluate the impact of extreme events on soil erosion, iii) the expert knowledge of the LANDSOIL model, a catchment-scale integrated approach of the soil-landscape system that enables to simulate both the sediment fluxes at the catchment outlet and the intra-catchment soil evolving properties and iv) the multi-disciplinarity of the involved researchers with an international reputation in the fields of soil science

Mapping Soil Erosion Factors and Potential Erosion Risk for the National Park "Central Balkan"

NASA Astrophysics Data System (ADS)

Ilieva, Diliana; Malinov, Ilia

2014-05-01

Soil erosion is widely recognised environmental problem. The report aims at presenting the main results from assessment and mapping of the factors of sheet water erosion and the potential erosion risk on the territory of National Park "Central Balkan". For this purpose, the Universal Soil Loss Equation (USLE) was used for predicting soil loss from erosion. The influence of topography (LS-factor) and soil erodibility (K-factor) was assessed using small-scale topographic and soil maps. Rainfall erosivity (R-factor) was calculated from data of rainfalls with amounts exceeding 9.5 mm from 14 hydro-meteorological stations. The values of the erosion factors (R, K and LS) were presented for the areas of forest, sub-alpine and alpine zones. Using the methods of GIS, maps were plotted presenting the area distribution among the classes of the soil erosion factors and the potential risk in the respective zones. The results can be used for making accurate decisions for soil conservation and sustainable land management in the park.

Carbon Erosion in the Great Karoo Region of South Africa

NASA Astrophysics Data System (ADS)

Krenz, Juliane; Greenwood, Philip; Kuhn, Brigitte; Foster, Ian; Boardman, John; Meadows, Mike; Kuhn, Nikolaus

2015-04-01

Work undertaken in the seasonally arid upland areas of the Great Karoo region of South Africa has established a link between land degradation and overgrazing which began in the second half of the 18th century when European farmers first settled the area. Ongoing land use change and shifting rainfall patterns resulted in the development of badlands on foot slopes of upland areas, and gully systems on valley bottoms. As a consequence of agricultural intensification and overgrazing, accompanied by a higher water demand, many small reservoirs were constructed, most of which are now in-filled with sediment. The deposited material serves as an environmental archive by which land use change over the last 100 years can be analysed, but with a particular focus on erosion and deposition of soil-associated carbon (C). It is assumed that erosion caused an initial flush of carbon rich soil which was subsequently buried and stored off-site. Despite this assumption, however the net-effect of erosion on carbon dioxide emissions is still unknown. In this project, preliminary results are presented from an investigation to determine whether land degradation in the Karoo has resulted in a shift from a net sink of C to a net source of C. Firstly, a high resolution digital elevation model was generated and erosion modelling was then employed to create an erosion risk map showing areas most prone to erosion. Information from the model output then served as the basis for ground-truthing and on-site erosion mapping. Secondly, sediment deposits from silted reservoirs were analysed for varying physicochemical parameters, in order to reconstruct spatial patterns of erosion and deposition. Analysis of total carbon (TC) content revealed a sharp decrease with decreasing depth. This provisionally suggests that land degradation during and after post-European settlement probably led to accelerated erosion of the relatively fertile surface soils. This presumably resulted in the rapid in-filling of

Soil erosion modelling for NSW coastal catchments using RUSLE in a GIS environment

NASA Astrophysics Data System (ADS)

Yang, Xihua; Chapman, Greg

2006-10-01

In this study, hillslope erosion risk has been estimated for all eastern New South Wales (NSW) catchments, Australia using Revised Universal Soil Loss Equation (RUSLE) in a geographic information system (GIS) environment. Rainfall-runoff erosivity (R) factor was interpolated from NSW rainfall-erosivity contour (isoerodent) data. Soil erodibility (K) factor was based on the soil regolith stability and sediment yield classification. The classification was derived from soil landscape and related soil map data. The slope length and steepness (LS) factor was derived from high resolution digital elevation model (DEM). A fully-automated program using Arc Macro Language (AML) produced RUSLE-based LS factor grids for all coastal catchments. The outputs are comparable to the range of LS values summarised in the literature. Cover and management (C) factor and conservation support-practices (P) factor were set to one. They are intended to be allocated according to land use, ground cover and erosion control provisions for particular land management actions. The resulting erosion risk map, with pixel size of 25-m, provides unprecedented resolution of relative expected sheet and rill erosion across all NSW costal catchments and can be adapted for a range of erosion control purposes such as bushfire hazard reduction and comprehensive costal assessment.

Erosion Effects

NASA Technical Reports Server (NTRS)

2003-01-01

[figure removed for brevity, see original site]

The impact crater in this THEMIS image is a model illustration to the effects of erosion on Mars. The degraded crater rim and several landslides observed in crater walls is evidence to the mass wasting of materials. Layering in crater walls also suggests the presence of materials that erode at varying rates.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Image information: VIS instrument. Latitude 31.6, Longitude 44.3 East (315.7 West). 19 meter/pixel resolution.

Nozzle erosion characterization and minimization for high-pressure rocket motor applications

NASA Astrophysics Data System (ADS)

Evans, Brian

Understanding of the processes that cause nozzle throat erosion and developing methods for mitigation of erosion rate can allow higher operating pressures for advanced rocket motors. However, erosion of the nozzle throat region, which is a strong function of operating pressure, must be controlled to realize the performance gains of higher operating pressures. The objective of this work was the study the nozzle erosion rates at a broad range of pressures from 7 to 34.5 MPa (1,000 to 5,000 psia) using two different rocket motors. The first is an instrumented solidpropellant motor (ISPM), which uses two baseline solid propellants; one is a non-metallized propellant called Propellant S and the other is a metallized propellant called Propellant M. The second test rig is a non-metallized solid-propellant rocket motor simulator (RMS). The RMS is a gas rocket with the ability to vary the combustion-product species composition by systematically varying the flow rates of gaseous reactants. Several reactant mixtures were utilized in the study to determine the relative importance of different oxidizing species (such as H2O, OH, and CO2). Both test rigs are equipped with a windowed nozzle section for real-time X-ray radiography diagnostics of the instantaneous throat variations for deducing the instantaneous erosion rates. The nozzle test section for both motors can also incorporate a nozzle boundary-layer control system (NBLCS) as a means of nozzle erosion mitigation. The effectiveness of the NBLCS at preventing nozzle throat erosion was demonstrated for both the RMS and the ISPM motors at chamber pressures up to 34 MPa (4930 psia). All tests conducted with the NBLCS showed signs of coning of the propellant surface, leading to increased mass burning rate and resultant chamber pressure. Two correlations were developed for the nozzle erosion rates from solid propellant testing, one for metallized propellant and one for non-metallized propellants. The non-metallized propellant

Beach Nourishment Techniques. Report 3. Typical U.S. Beach Nourishment Projects Using Offshore Sand Deposits.

DTIC Science & Technology

1981-05-01

Cooperative Beach Erosion Control Project at Presque Isle Peninsula, Erie , Pennsylvania ," Buffalo, N. Y. U. S. Army Engineer District, Charleston. 1963 (Mar...104 Presque Isle , Pa .. .. ..................... 109 REFERENCES .. ............................ 115 2A BEACH NOURISHMENT...RIVER COUNTY, FL T PRESQUE ISLE . PA Figure 1. Beach fill projects location map ...../ ...... studies have been authorized, or which are publicly owned

Saliva and dental erosion

PubMed Central

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

Saliva and dental erosion.

PubMed

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. This review discusses the role of salivary factors on the development of dental erosion. 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. 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. 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.

Contrasting Modern and 10Be- derived erosion rates for the Southern Betic Cordillera, Spain

NASA Astrophysics Data System (ADS)

Bellin, N.; Vanacker, V.; Kubik, P.

2012-04-01

In Europe, Southeast Spain was identified as one of the regions with major treat of desertification in the context of future land use and climate change. During the last years, significant progress has been made to understand spatial patterns of modern erosion rates in these semi-arid degraded environments. Numerous European projects have contributed to the collection of modern erosion data at different spatial scales for Southeast Spain. However, these data are rarely analysed in the context of long-term changes in vegetation, climate and human occupation. In this paper, we present Modern and Holocene denudation rates for small river basins (1 to 10 km2) located in the Spanish Betic Cordillera. Long-term erosion data were derived from cosmogenic nuclide analyses of river-borne sediment. Modern erosion data were quantified through analysis of sediment deposition volumes behind check dams, and represent average erosion rates over the last 10 to 40 years. Modern erosion rates are surprisingly low (mean erosion rate = 0.048 mm y-1; n=36). They indicate that the steep, sparsely vegetated hillslopes in the Betic Cordillera cannot directly be associated with high erosion rates. 10Be -derived erosion rates integrate over the last 37500 to 3500 years, and are roughly of the same magnitude. They range from 0.013 to 0.243 mm y-1 (mean denudation rate = 0.062 mm y-1 ± 0.054; n=20). Our data suggest that the modern erosion rates are similar to the long-term erosion rates in this area. This result is in contrast with the numerous reports on human-accelerated modern erosion rates for Southeast Spain. Interestingly, our new data on long-term erosion rates show a clear spatial pattern, with higher erosion rates in the Sierra Cabrera and lower erosion rates in Sierra de las Estancias, and Sierra Torrecilla. Preliminary geomorphometric analyses suggest that the spatial variation that we observe in long-term erosion rates is related to the gradient in uplift rates of the Betic

Highly erodible terrain in agriculture land against chipped pruned branches. Or how to stop the soil erosion with low investment

NASA Astrophysics Data System (ADS)

Cerdà, A.

2009-04-01

The session on "Soil erosion and sediment control with vegetation and bioengineering on severely eroded terrain" pays special attention to the severe soil erosion suffered on steep slopes and erodible parent materials and soils. Within the last 20 years, in the Mediterranean lands, the citrus orchards were reallocated on steep slopes due to the urban development and better climatic and management conditions of the new plantations. The lack of vegetation cover on the new slope plantations of citrus resulted in high erosion rates. Those non-sustainable soil losses were measured by means of rainfall simulation experiments, Gerlach collectors, geomorphological transect and topographical measurements. The October 2007 and October 2008 rainy periods resulted in sheet, rill and gully erosion. Some recently planted orchards (2005) had the first pruning season in 2008. The pruned chipped branches reduced the soil losses to 50 % of the expected, although the litter (pruned branches) covered 4.67 % of the soil. This is why a research was developed by means of simulated rainfall experiments to determine the vegetation cover (litter, mainly leaves) to protect the soil to reach a sustainable erosion rate. Rainfall simulation experiments at 43 mm h-1 where performed on 1 m2 plots covered with 0, 3, 7, 15, 30, 45, 60, 80 and 100 % litter cover (pruned chipped branches) to determine the sustainable litter cover to avoid the soil losses. The results show that more that 45 % litter cover almost reduces the soil losses to negligible rates. The results confirm that 4 % of vegetation cover reduces the soil losses to 50 %. Key words: Agriculture land, erodible terrain, land management, citrus, erosion, Spain, Valencia, herbicides. Acknowledgements, We thanks the financial support of the Ministerio de Ciencia e Innovación by means of the project CGL2008-02879/BTE, "PERDIDA DE SUELO EN NUEVAS EXPLOTACIONES CITRICOLAS EN PENDIENTE. ESTRATEGIAS PARA EL CONTROL DE LA EROSION HIDRICA"

Rainfall erosivity in Europe.

PubMed

Panagos, Panos; Ballabio, Cristiano; Borrelli, Pasquale; Meusburger, Katrin; Klik, Andreas; Rousseva, Svetla; Tadić, Melita Perčec; Michaelides, Silas; Hrabalíková, Michaela; Olsen, Preben; Aalto, Juha; Lakatos, Mónika; Rymszewicz, Anna; Dumitrescu, Alexandru; Beguería, Santiago; Alewell, Christine

2015-04-01

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 R-factor 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 on the best available datasets. Data have been collected from 1541 precipitation stations in all European Union (EU) Member States and Switzerland, with temporal resolutions of 5 to 60 min. The R-factor values calculated from precipitation data of different temporal resolutions were normalised to R-factor values with temporal resolutions of 30 min using linear regression functions. Precipitation time series ranged from a minimum of 5 years to a maximum of 40 years. The average time series per precipitation station is around 17.1 years, the most datasets including the first decade of the 21st century. 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, average temperature), elevation and latitude/longitude. The mean R-factor for the EU plus Switzerland is 722 MJ mm ha(-1) h(-1) yr(-1), with the highest values (>1000 MJ mm ha(-1) h(-1) yr(-1)) in the Mediterranean and alpine regions and the lowest (<500 MJ mm ha(-1) h(-1) yr(-1)) in the Nordic countries. The erosivity density (erosivity normalised to annual precipitation amounts) was also the highest in Mediterranean regions which implies high risk for erosive events and floods

Coastal erosion and accretion rates in Greece

NASA Astrophysics Data System (ADS)

Foteinis, Spyros; Papadopoulos, Costas; Koutsogiannaki, Irini; Synolakis, Costas

2010-05-01

Erosion threatens many coastal regions of Greece. Anthropogenic changes of landforms such as coastal roads built on even narrow beaches, sand mining for construction, poor design of coastal structures that interfere with sediment, and dams without sediment bypasses have significantly reduced beach widths. We present erosion rates for different beaches, some of which are in sensitive ecosystems, otherwise "protected" by local and EU ordinances. By comparing inferences of beach widths in varying intervals from 1933 to 2006, we infer that the construction of dams in Acheloos river in western Greece, built in a faraonic attempt to partially divert its flows to eastern Greece, this is responsible for up to 20m/year erosion rates observed in certain locales in the Acheloos delta. More characteristic erosion rates in the region are ~ 2m/year. By contrast, there appears rapid accretion of up to 4m/year in the beaches around the Nestos delta in northern Greece (Papadopoulos, 2009). In beaches that are not near large river deltas, erosion rates range from 0.5m/year to 1m/year. While we have not done comprehensive comparisons among coastlines with different levels of coastal development, it does appear that rapid coastal development correlates well with erosion rates. The underlying problem is the complete lack of any semblance of coastal zone management in Greece and substandard design of coastal structures, which are often sited without any measurements of waves and currents offshore (Synolakis et al, 2008). Beach maintenance remains an exotic concept for most local authorities, who invariably prefer to build hard coastal structures to "protect" versus nourish, siting lack of experience with nourishment and "environmental" concerns. In certain cases, choices are dictated by costs, the larger the cost the easier the project gets approved by regulatory authorities, hence the preference for concrete or rubble structures. We conclude that, unless urgent salvage measures are

Extreme coastal erosion enhanced by anomalous extratropical storm wave direction.

PubMed

Harley, Mitchell D; Turner, Ian L; Kinsela, Michael A; Middleton, Jason H; Mumford, Peter J; Splinter, Kristen D; Phillips, Matthew S; Simmons, Joshua A; Hanslow, David J; Short, Andrew D

2017-07-20

Extratropical cyclones (ETCs) are the primary driver of large-scale episodic beach erosion along coastlines in temperate regions. However, key drivers of the magnitude and regional variability in rapid morphological changes caused by ETCs at the coast remain poorly understood. Here we analyze an unprecedented dataset of high-resolution regional-scale morphological response to an ETC that impacted southeast Australia, and evaluate the new observations within the context of an existing long-term coastal monitoring program. This ETC was characterized by moderate intensity (for this regional setting) deepwater wave heights, but an anomalous wave direction approximately 45 degrees more counter-clockwise than average. The magnitude of measured beach volume change was the largest in four decades at the long-term monitoring site and, at the regional scale, commensurate with that observed due to extreme North Atlantic hurricanes. Spatial variability in morphological response across the study region was predominantly controlled by alongshore gradients in storm wave energy flux and local coastline alignment relative to storm wave direction. We attribute the severity of coastal erosion observed due to this ETC primarily to its anomalous wave direction, and call for greater research on the impacts of changing storm wave directionality in addition to projected future changes in wave heights.

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

NASA Astrophysics Data System (ADS)

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.

A Study of Cavitation Erosion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hiromu Isaka; Masatsugu Tsutsumi; Tadashi Shiraishi

2002-07-01

The authors performed experimental study for the purpose of the following two items from a viewpoint of cavitation erosion of a cylindrical orifice in view of a problem at the letdown orifice in PWR (Pressurized Water Reactor). 1. To get the critical cavitation parameter of the cylindrical orifice to establish the design criteria for prevention of cavitation erosion, and 2. to ascertain the erosion rate in such an eventuality that the cavitation erosion occurs with the orifice made of stainless steel with precipitation hardening (17-4-Cu hardening type stainless steel), so that we confirm the appropriateness of the design criteria. Regardingmore » the 1. item, we carried out the cavitation tests to get the critical cavitation parameters inside and downstream of the orifice. The test results showed that the cavitation parameter at inception is independent of the length or the diameter of the orifice. Moreover, the design criteria of cavitation erosion of cylindrical orifices have been established. Regarding the 2. item, we tested the erosion rate under high-pressure conditions. The cavitation erosion actually occurred in the cylindrical orifice at the tests that was strongly resemble to the erosion occurred at the plant. It will be seldom to reproduce resemble cavitation erosion in a cylindrical orifice with the hard material used at plants. We could establish the criteria for preventing the cavitation erosion from the test results. (authors)« less

Reduced Net Erosion of High-Z PFC Materials in DIII-D Divertor

NASA Astrophysics Data System (ADS)

Rudakov, D. L.; Stangeby, P. C.; Elder, J. D.; Wampler, W. R.; Buchenauer, D. A.; Watkins, J. G.; Brooks, J. N.; Hassanein, A.; Sizyuk, T.; Briesemeister, A. R.; McLean, A. G.; Chrobak, C. P.; Guo, H. Y.; Leonard, A. W.; Wong, C. P. C.

2014-10-01

DiMES samples featuring 1 cm and 1 mm diameter W films deposited on a Si substrate were exposed in DIII-D near the attached outer strike point of LSN L-mode discharges. The measured net and gross erosion rates of W, determined from post-mortem ion beam analysis (IBA) of 1 cm and 1 mm samples, were 0.14 and 0.48 nm/s, respectively, giving net/gross erosion ratio of 0.29. REDEP/WBC modeling of this experiment yielded a very close ratio of 0.33. Projection of the modeling results to ITER shows very low net erosion of W. In another experiment Mo-coated samples were exposed with 13CH4 gas injected ~2 cm upstream of DiMES. Reduction of Mo erosion was evidenced in - situ by the suppression of MoI line radiation. Post-mortem IBA showed that the net erosion of Mo was below the measurement resolution of 0.5 nm, corresponding to a rate of <=0.07 nm/s. Compared to the previously measured erosion rates, this constitutes a reduction of more than 10X. Work supported in part the by US DOE under DE-FG02-07ER54917, DE-AC04-94AL85000, DE-AC05-00OR22725, DE-AC52-07NA27344 & DE-FC02-04ER54698.

Project Summary Report : Evaluation of Effectiveness and Cost-Benefits of Woolen Roadside Reclamation Products

DOT National Transportation Integrated Search

2017-12-01

Wool has been used by humans for millennia for clothing, blankets, and even for housing like the yurts of central Asia. This project took a fresh look at wool and explored its potential for incorporation in erosion control blankets (ECBs) and to incr...

Soil tillage conservation and its effect on erosion control, water management and carbon sequestration

NASA Astrophysics Data System (ADS)

Rusu, Dr.; Gus, Dr.; Bogdan, Dr.; Moraru, Dr.; Pop, Dr.; Clapa, Dr.; Pop, Drd.

2009-04-01

fuel for preparing the germination bed. Presently it is necessary a change concerning the concept of conservation practices and a new approach regarding the control of erosion. The real conservation of soil must be expanded beyond the traditional understanding of soil erosion. The real soil conservation is represented by carbon management. We need to focus to another level concerning conservation by focusing on of soil quality. Carbon management is necessary for a complex of matters including soil, water management, field productivity, biological fuel and climatic change. Profound research is necessary in order to establish the carbon sequestration practices and their implementation impact.

Rill erosion rates in burned forests

Treesearch

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...

In situ effect of CPP-ACP chewing gum upon erosive enamel loss.

PubMed

Alencar, Catarina Ribeiro Barros de; Oliveira, Gabriela Cristina de; Magalhães, Ana Carolina; Buzalaf, Marília Afonso Rabelo; Machado, Maria Aparecida de Andrade Moreira; Honório, Heitor Marques; Rios, Daniela

2017-01-01

This in situ study investigated the ability of a CPP-ACP chewing gum in preventing erosive enamel loss. Material and Methods: During three experimental crossover phases (one phase per group) of seven days each, eight volunteers wore palatal devices with human enamel blocks. The groups were: GI - Sugar free chewing gum with CPP-ACP; GII - Conventional sugar free chewing gum; and GIII - No chewing gum (control). Erosive challenge was extraorally performed by immersion of the enamel blocks in cola drink (5 min, 4x/day). After each challenge, in groups CPP and No CPP, volunteers chewed one unit of the corresponding chewing gum for 30 minutes. Quantitative analysis of enamel loss was performed by profilometry (µm). Data were analyzed by Repeated-Measures ANOVA and Tukey's test (p<0.05). The use of chewing gum (CPP and No CPP) resulted in lower erosive enamel loss compared with the control group (p<0.05). CPP-ACP chewing gum (CPP) did not improve the protection against erosive enamel loss compared with conventional chewing gum (No CPP) (p>0.05). The CPP-ACP chewing gum was not able to enhance the anti-erosive effect of conventional chewing gum against enamel loss.

ANSI/ASAE S422.1 DEC2015: Mapping symbols and nomenclature for erosion and sediment control plans for land disturbing activities

USDA-ARS?s Scientific Manuscript database

Erosion and sediment control plans are implemented across a broad range of land disturbing situations and intensities, and may differ depending on the needs and configurations, both spatial and temporal, of the individual situations. Maintaining consistency in definition, mapping symbol, and nomencl...

Estimates of soil erosion using cesium-137 tracer models.

PubMed

Saç, M M; Uğur, A; Yener, G; Ozden, B

2008-01-01

The soil erosion was studied by 137Cs technique in Yatagan basin in Western Turkey, where there exist intensive agricultural activities. This region is subject to serious soil loss problems and yet there is not any erosion data towards soil management and control guidelines. During the soil survey studies, the soil profiles were examined carefully to select the reference points. The soil samples were collected from the slope facets in three different study areas (Kirtas, Peynirli and Kayisalan Hills). Three different models were applied for erosion rate calculations in undisturbed and cultivated sites. The profile distribution model (PDM) was used for undisturbed soils, while proportional model (PM) and simplified mass balance model (SMBM) were used for cultivated soils. The mean annual erosion rates found using PDM in undisturbed soils were 15 t ha(-1) year(-1) at the Peynirli Hill and 27 t ha(-1) year(-1) at the Kirtas Hill. With the PM and SMBM in cultivated soils at Kayişalan, the mean annual erosion rates were obtained to be 65 and 116 t ha(-1) year(-1), respectively. The results of 137Cs technique were compared with the results of the Universal Soil Loss Equation (USLE).

NASA Project Planning and Control Handbook

NASA Technical Reports Server (NTRS)

Moreland, Robert; Claunch, Cathy L.

2016-01-01

This handbook provides an overview of the fundamental principles and explains the functions and products that go into project planning and control. The 2010 Interim Results of the NASA Program Planning and Control (PPC) Study identified seven categories of activities for PPC, and those provide the basis for the seven functions described in this handbook. This handbook maps out the interfaces and interactions between PPC functions, as well as their external interfaces. This integration of information and products within and between functions is necessary to form the whole picture of how a project is progressing. The handbook descriptions are meant to facilitate consistent, common, and comprehensive approaches for providing valued analysis, assessment, and evaluation focused on the project level at NASA. The handbook also describes activities in terms of function rather than the job title or the specific person or organization responsible for the activity, which could differ by Center or size of a project. This handbook is primarily guidance for project planning and control: however, the same principles apply to programs and generally apply to institutional planning and control.

Development of an inexpensive optical method for studies of dental erosion process in vitro

NASA Astrophysics Data System (ADS)

Nasution, A. M. T.; Noerjanto, B.; Triwanto, L.

2008-09-01

Teeth have important roles in digestion of food, supporting the facial-structure, as well as in articulation of speech. Abnormality in teeth structure can be initiated by an erosion process due to diet or beverages consumption that lead to destruction which affect their functionality. Research to study the erosion processes that lead to teeth's abnormality is important in order to be used as a care and prevention purpose. Accurate measurement methods would be necessary as a research tool, in order to be capable for quantifying dental destruction's degree. In this work an inexpensive optical method as tool to study dental erosion process is developed. It is based on extraction the parameters from the 3D dental visual information. The 3D visual image is obtained from reconstruction of multiple lateral projection of 2D images that captured from many angles. Using a simple motor stepper and a pocket digital camera, sequence of multi-projection 2D images of premolar tooth is obtained. This images are then reconstructed to produce a 3D image, which is useful for quantifying related dental erosion parameters. The quantification process is obtained from the shrinkage of dental volume as well as surface properties due to erosion process. Results of quantification is correlated to the ones of dissolved calcium atom which released from the tooth using atomic absorption spectrometry. This proposed method would be useful as visualization tool in many engineering, dentistry, and medical research. It would be useful also for the educational purposes.

Testing model parameters for wave-induced dune erosion using observations from Hurricane Sandy

NASA Astrophysics Data System (ADS)

Overbeck, J. R.; Long, J. W.; Stockdon, H. F.

2017-01-01

Models of dune erosion depend on a set of assumptions that dictate the predicted evolution of dunes throughout the duration of a storm. Lidar observations made before and after Hurricane Sandy at over 800 profiles with diverse dune elevations, widths, and volumes are used to quantify specific dune erosion model parameters including the dune face slope, which controls dune avalanching, and the trajectory of the dune toe, which controls dune migration. Wave-impact models of dune erosion assume a vertical dune face and erosion of the dune toe along the foreshore beach slope. Observations presented here show that these assumptions are not always valid and require additional testing if these models are to be used to predict coastal vulnerability for decision-making purposes. Observed dune face slopes steepened by 43% yet did not become vertical faces, and only 50% of the dunes evolved along a trajectory similar to the foreshore beach slope. Observations also indicate that dune crests were lowered during dune erosion. Moreover, analysis showed a correspondence between dune lowering and narrower beaches, smaller dune volumes, and/or longer wave impact.

Testing model parameters for wave‐induced dune erosion using observations from Hurricane Sandy

USGS Publications Warehouse

Overbeck, Jacquelyn R.; Long, Joseph W.; Stockdon, Hilary F.

2017-01-01

Models of dune erosion depend on a set of assumptions that dictate the predicted evolution of dunes throughout the duration of a storm. Lidar observations made before and after Hurricane Sandy at over 800 profiles with diverse dune elevations, widths, and volumes are used to quantify specific dune erosion model parameters including the dune face slope, which controls dune avalanching, and the trajectory of the dune toe, which controls dune migration. Wave‐impact models of dune erosion assume a vertical dune face and erosion of the dune toe along the foreshore beach slope. Observations presented here show that these assumptions are not always valid and require additional testing if these models are to be used to predict coastal vulnerability for decision‐making purposes. Observed dune face slopes steepened by 43% yet did not become vertical faces, and only 50% of the dunes evolved along a trajectory similar to the foreshore beach slope. Observations also indicate that dune crests were lowered during dune erosion. Moreover, analysis showed a correspondence between dune lowering and narrower beaches, smaller dune volumes, and/or longer wave impact.

Erosion Control and Recultivation Measures at a Headrace Channel of a Hydroelectric Power Plant using Different Combined Soil Bioengineering Techniques

NASA Astrophysics Data System (ADS)

Obriejetan, M.; Florineth, F.; Rauch, H. P.

2012-04-01

As a consequence of land use change resulting in an increased number of slope protection constructions and with respect to effects associated with climate change like extremes in temperatures and temperature variations or increased frequency of heavy precipitation, adaptation strategies for sustainable erosion protection systems are needed which meet ecological compatibility and economical requirements. Therefore a wide range of different technical solutions respectively geotextiles and geotextile-related products (blankets, nettings, grids etc.) are available on the market differing considerably in function, material, durability and pricing. Manufacturers usually provide product-specific information pertaining to application field, functional range or (technical) installation features whereas vegetational aspects are frequently neglected while vegetation can contribute substantially to increased near-surface erosion protection respectively slope stability. Though, the success of sustainable erosion control is directly dependent on several vegetational aspects. Adequate development of a functional vegetation layer in combination with geotextiles is closely associated to application aspects such as seeding technique, sowing date and intensity, seed-soil contact or maintenance measures as well as to qualitative aspects like seed quality, germination rates, area of origin, production method or certification. As a general guideline, erosion control within an initial phase is directly related to restoration techniques whereas vegetation specifics with regard to species richness or species composition play a key role in medium to long-term development and slope protection. In this context one of the fundamental objectives of our study is the identification and subsequently the determination of the main interaction processes between technical and biological components of combined slope protection systems. The influence of different geotextile characteristics on specific

Solid impingement erosion mechanisms and characterization of erosion resistance of ductile metals

NASA Technical Reports Server (NTRS)

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

1982-01-01

Experimental results pertaining to spherical glass bead and angular crushed glass particle impingement are presented. A concept of energy adsorption to explain the failure of material is proposed. The erosion characteristics of several pure metals were correlated with the proposed energy parameters and with other properties. Correlations of erosion and material properties were also carried out with these materials to study the effect of the angle of impingement. Analyses of extensive erosion data indicate that surface energy, strain energy, melting point, bulk modulus, hardness, ultimate resilience, atomic volume and product of linear coefficient of thermal expansion, bulk modulus, and temperature rise required for melting, and ultimate resilience, and hardness exhibit the best correlations. It appears that both energy and thermal properties contribute to the total erosion.

Field studies of beach cones as coastal erosion control/reversal devices for areas with significant oil and gas activities. Technical progress report, April--June 1992 and Project status report, June 1992

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1992-07-17

A field demonstration/study of a novel shoreline erosion protection device called beach cones is planned. These patented, fiberglass- reinforced concreted devices are to be deployed in a number of geometric patterns at seven location in the Bastian Bay area of Western Plaquemines Parish. The purpose of the work described in this report was to evaluate the proposed study`s impact on living and non-living shellfish resources within each of the project`s seven separate Study Areas. Major accomplishments for this reporting period were as follows: aerial photographs of the experimental sites were taken; all permit applications were filed; information was submitted formore » the Environmental Report; several reconnaissance trips to the experimental sites were made; meetings were held among all participating organizations to further plan the research; permit was obtained from the US Army Corps of Engineers; test sites were surveyed by the Xavier University contingent; survey data were taken at all sites; the Oyster Assessment was completed; permit was obtained from the State of Louisiana Department of Natural Resources; and initial survey data were finalized at all sites.« less

Erosion of Perennially Frozen Streambanks,

DTIC Science & Technology

1983-12-01

erosional processes. Factors that determine rates and locations of erosion in- dude physical, thermal and structural properties of bank sediments , stream...Program, Environmental Impact, and Civil Works Work Unit CWIS 31722, Sediment Transport and Deposition in Northern Rivers; Research Area, Flood Control...between bank and bluff zones of eroding, perennially frozen streambanks 4 3. Cantilevered blocks of frozen sediment above thermoerosional niche, northern

Urine metabolic profiling for the pathogenesis research of erosive oral lichen planus.

PubMed

Li, Xu-Zhao; Yang, Xu-Yan; Wang, Yu; Zhang, Shuai-Nan; Zou, Wei; Wang, Yan; Li, Xiao-Nan; Wang, Ling-Shu; Zhang, Zhi-Gang; Xie, Liang-Zhen

2017-01-01

Oral lichen planus (OLP) is a relatively common chronic immune-pathological and inflammatory disease and potentially oral precancerous lesion. Erosive OLP patients show the higher rate of malignant transformation than patients with non-erosive OLP. Identifying the potential biomarkers related to erosive OLP may help to understand the pathogenesis of the diseases. Metabolic profiles were compared in control and patient subjects with erosive OLP by using ultra-performance liquid chromatography-quadrupole time-of-flight-mass spectrometry (UPLC-QTOF-MS) coupled with pattern recognition methods An integrative analysis was used to identify the perturbed metabolic pathways and pathological processes that may be associated with the disease. In total, 12 modulated metabolites were identified and considered as the potential biomarkers of erosive OLP. Multiple metabolic pathways and pathological processes were involved in erosive OLP. The dysregulations of these metabolites could be used to explain the pathogenesis of the disease, which could also be the potential therapeutic targets for the disease. Copyright © 2016 Elsevier Ltd. All rights reserved.

Scales and erosion

USDA-ARS?s Scientific Manuscript database

There is a need to develop scale explicit understanding of erosion to overcome existing conceptual and methodological flaws in our modelling methods currently applied to understand the process of erosion, transport and deposition at the catchment scale. These models need to be based on a sound under...

Raindrop and flow interactions for interrill erosion with wind-driven rain

USDA-ARS?s Scientific Manuscript database

Wind-driven rain (WDR) experiments were conducted to evaluate interrill component of the Water Erosion Prediction Project (WEPP) model with two-dimensional experimental set-up in wind tunnel. Synchronized wind and rain simulations were applied to soil surfaces on windward and leeward slopes of 7, 15...

Shoreline Erosion Processes: Orwell Lake, Minnesota.

DTIC Science & Technology

1984-12-01

1976) and Savat ( 1981 ) found such splash layer Will absorb much of the impact of the rain- erosion to increase with increasing slope angle, but...pp. 188-196. U.S. Army Corps of Engineers (1979) Flood control, Savat , J. ( 1981 ) Work done by splash: Laboratory Orwell Dam, Otter Tail River

Erosional Consequence of Saltcedar Control

NASA Astrophysics Data System (ADS)

Vincent, Kirk R.; Friedman, Jonathan M.; Griffin, Eleanor R.

2009-08-01

Removal of nonnative riparian trees is accelerating to conserve water and improve habitat for native species. Widespread control of dominant species, however, can lead to unintended erosion. Helicopter herbicide application in 2003 along a 12-km reach of the Rio Puerco, New Mexico, eliminated the target invasive species saltcedar ( Tamarix spp.), which dominated the floodplain, as well as the native species sandbar willow ( Salix exigua Nuttall), which occurred as a fringe along the channel. Herbicide application initiated a natural experiment testing the importance of riparian vegetation for bank stability along this data-rich river. A flood three years later eroded about 680,000 m3 of sediment, increasing mean channel width of the sprayed reach by 84%. Erosion upstream and downstream from the sprayed reach during this flood was inconsequential. Sand eroded from channel banks was transported an average of 5 km downstream and deposited on the floodplain and channel bed. Although vegetation was killed across the floodplain in the sprayed reach, erosion was almost entirely confined to the channel banks. The absence of dense, flexible woody stems on the banks reduced drag on the flow, leading to high shear stress at the toe of the banks, fluvial erosion, bank undercutting, and mass failure. The potential for increased erosion must be included in consideration of phreatophyte control projects.

Erosional consequence of saltcedar control

USGS Publications Warehouse

Vincent, K.R.; Friedman, J.M.; Griffin, E.R.

2009-01-01

Removal of nonnative riparian trees is accelerating to conserve water and improve habitat for native species. Widespread control of dominant species, however, can lead to unintended erosion. Helicopter herbicide application in 2003 along a 12-km reach of the Rio Puerco, New Mexico, eliminated the target invasive species saltcedar (Tamarix spp.), which dominated the floodplain, as well as the native species sandbar willow (Salix exigua Nuttall), which occurred as a fringe along the channel. Herbicide application initiated a natural experiment testing the importance of riparian vegetation for bank stability along this data-rich river. A flood three years later eroded about 680,000 m3 of sediment, increasing mean channel width of the sprayed reach by 84%. Erosion upstream and downstream from the sprayed reach during this flood was inconsequential. Sand eroded from channel banks was transported an average of 5 km downstream and deposited on the floodplain and channel bed. Although vegetation was killed across the floodplain in the sprayed reach, erosion was almost entirely confined to the channel banks. The absence of dense, flexible woody stems on the banks reduced drag on the flow, leading to high shear stress at the toe of the banks, fluvial erosion, bank undercutting, and mass failure. The potential for increased erosion must be included in consideration of phreatophyte control projects. ?? 2009 U.S. Government.

Evaluation of Erosion Potential of Estuarine Sediments in NY/NJ Harbor (Impact of In-Situ Stabilization on the Remediation of Soft Sediments - A preamble to Erosion Testing and Evaluation)

DOT National Transportation Integrated Search

2011-09-01

The primary objective of the project are to perform a review of existing in-situ techniques of sediment erosion potential evaluation in contaminated "superfund" sites in the United States and those from Europe and Japan and the applicability of soft ...

Current and future assessments of soil erosion by water on the Tibetan Plateau based on RUSLE and CMIP5 climate models.

PubMed

Teng, Hongfen; Liang, Zongzheng; Chen, Songchao; Liu, Yong; Viscarra Rossel, Raphael A; Chappell, Adrian; Yu, Wu; Shi, Zhou

2018-04-18

Soil erosion by water is accelerated by a warming climate and negatively impacts water security and ecological conservation. The Tibetan Plateau (TP) has experienced warming at a rate approximately twice that observed globally, and heavy precipitation events lead to an increased risk of erosion. In this study, we assessed current erosion on the TP and predicted potential soil erosion by water in 2050. The study was conducted in three steps. During the first step, we used the Revised Universal Soil Equation (RUSLE), publicly available data, and the most recent earth observations to derive estimates of annual erosion from 2002 to 2016 on the TP at 1-km resolution. During the second step, we used a multiple linear regression (MLR) model and a set of climatic covariates to predict rainfall erosivity on the TP in 2050. The MLR was used to establish the relationship between current rainfall erosivity data and a set of current climatic and other covariates. The coefficients of the MLR were generalised with climate covariates for 2050 derived from the fifth phase of the Coupled Model Intercomparison Project (CMIP5) models to estimate rainfall erosivity in 2050. During the third step, soil erosion by water in 2050 was predicted using rainfall erosivity in 2050 and other erosion factors. The results show that the mean annual soil erosion rate on the TP under current conditions is 2.76tha -1 y -1 , which is equivalent to an annual soil loss of 559.59×10 6 t. Our 2050 projections suggested that erosion on the TP will increase to 3.17tha -1 y -1 and 3.91tha -1 y -1 under conditions represented by RCP2.6 and RCP8.5, respectively. The current assessment and future prediction of soil erosion by water on the TP should be valuable for environment protection and soil conservation in this unique region and elsewhere. Copyright © 2018 Elsevier B.V. All rights reserved.

Soil water erosion processes in mountain forest catchment - analysis by using terrestrial laser scanning

NASA Astrophysics Data System (ADS)

Dąbek, Paweł; Żmuda, Romuald; Szczepański, Jakub; Ćmielewski, Bartłomiej; Patrzałek, Ciechosław

2013-04-01

The paper presents the results of the analysis of the water erosion processes of soil occurring in forestry mountain catchment area in the region of West Sudetes Mountain in Poland. The research was carried out within the experimental area of skid trails (operational trails), which were used to the end of 2010 in obtaining wood and its mechanical transport to the place of storage. As a consequence of forestry works that were carried out it was changing the natural structure of ground and its surface on the wooded slopes, which, combined with the favorable hydro-meteorological conditions contributed to the intensification of the water erosion processes of soil on surface of trails. For the implementation of the research project of the analysis of water erosion processes in the forestry catchment area innovative was used terrestrial laser scanning. Using terrestrial laser scanning has enabled the analysis of the dynamics of erosion processes both in time, as well as in spatial and quantitative terms. Scanning was performed at a resolution of 4 mm, resulting in 62 500 points per 1 square meter. After filtering the data were interpolated to other resolution of 1 cm, which can identify even the smallest linear and surface effects of erosion. While installed on the experimental area, along the skid trails, anti-erosion barriers in order to reduce transport eroded material and allow its accumulation. Allowed to precisely determine the location of areas of accumulation, the rate and amount of accumulated material. The result of the analyses that was carried out is identification areas of denudation of the eroded material, and also determine the intensity of the erosion processes and their quantitative analysis. The long-term researches on hydrological conditions and forest complexes functioning show that forest effectively stores water, limits linear and surface flow and delays water outflow from a catchment. Carried out a research project using the terrestrial laser

Erosion in Mediterranean landscapes: Changes and future challenges

NASA Astrophysics Data System (ADS)

García-Ruiz, José M.; Nadal-Romero, Estela; Lana-Renault, Noemí; Beguería, Santiago

2013-09-01

Intense erosion processes are widespread in the Mediterranean region, and include sheet wash erosion, rilling, gullying, shallow landsliding, and the development of large and active badlands in both subhumid and semi-arid areas. This review analyses the main environmental and human features related to soil erosion processes, and the main factors that explain the extreme variability of factors influencing soil erosion, particularly recent land use changes. The importance of erosion in the Mediterranean is related to the long history of human activity in a region characterized by low levels of annual precipitation, the occurrence of intense rainstorms and long-lasting droughts, high evapotranspiration, the presence of steep slopes and the occurrence of recent tectonic activity, together with the recurrent use of fire, overgrazing and farming. These factors have resulted in a complex landscape in which intensification and abandonment, wealth and poverty can co-exist. The changing conditions of national and international markets and the evolution of population pressure are now the main drivers explaining land use changes, including farmland abandonment in mountain areas, the expansion of some subsidized crops to marginal lands, and the development of new terraces affected by landslides and intense soil erosion during extreme rainstorm events. The occurrence of human-related forest fires affecting thousands of hectares each year is a significant problem in both the northern and southern areas of the Mediterranean basin. Here, we highlight the rise of new scientific challenges in controlling the negative consequences of soil erosion in the Mediterranean region: 1) to reduce the effects and extent of forest fires, and restructure the spatial organization of abandoned landscapes; 2) to provide guidance for making the EU agricultural policy more adapted to the complexity and fragility of Mediterranean environments; 3) to develop field methods and models to improve the

Dynamics of Soil Organic Carbon and Microbial Biomass Carbon in Relation to Water Erosion and Tillage Erosion

PubMed Central

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 137Cs technique to determine the effects of water erosion and tillage erosion on the dynamics of SOC and MBC. Soil samples for the determination of 137Cs, SOC, MBC and soil particle-size fractions were collected on two types of contrasting hillslopes. 137Cs 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 <0.002-mm clay shows that water 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. PMID:23717530

A history of wind erosion prediction models in the United States Department of Agriculture prior to the Wind Erosion Prediction System

NASA Astrophysics Data System (ADS)

Tatarko, John; Sporcic, Michael A.; Skidmore, Edward L.

2013-09-01

The Great Plains experienced an influx of settlers in the late 1850s-1900. Periodic drought was hard on both settlers and the soil and caused severe wind erosion. The period known as the Dirty Thirties, 1931-1939, produced many severe windstorms, and the resulting dusty sky over Washington, DC helped Hugh Hammond Bennett gain political support for the Soil Conservation Act of 1937 that started the USDA Soil Conservation Service (SCS). Austin W. Zingg and William S. Chepil began wind erosion studies at a USDA laboratory at Kansas State University in 1947. Neil P. Woodruff and Francis H. Siddoway published the first widely used model for wind erosion in 1965, called the Wind Erosion Equation (WEQ). The WEQ was solved using a series of charts and lookup tables. Subsequent improvements to WEQ included monthly magnitudes of the total wind, a computer version of WEQ programmed in FORTRAN, small-grain equivalents for range grasses, tillage systems, effects of residue management, crop row direction, cloddiness, monthly climate factors, and the weather. The SCS and the Natural Resources Conservation Service (NRCS) produced several computer versions of WEQ with the goal of standardizing and simplifying it for field personnel including a standalone version of WEQ was developed in the late 1990s using Microsoft Excel. Although WEQ was a great advancement to the science of prediction and control of wind erosion on cropland, it had many limitations that prevented its use on many lands throughout the United States and the world. In response to these limitations, the USDA developed a process-based model know as the Wind Erosion Prediction System (WEPS). The USDA Agricultural Research Service has taken the lead in developing science and technology for wind erosion prediction.

Erosion in radial inflow turbines. Volume 4: Erosion rates on internal surfaces

NASA Technical Reports Server (NTRS)

Clevenger, W. B., Jr.; Tabakoff, W.

1975-01-01

An analytic study of the rate at which material is removed by ingested dust impinging on the internal surfaces of a typical radial inflow turbine is presented. Results show that there are several regions which experience very severe erosion loss, and other regions that experience moderate levels of erosion loss: (1) the greatest amount of material loss occurs on the trailing edges of the nozzle blades where very high velocity, moderate angle impacts occur. The tip regions of ductile materials are also subjected to serious levels of erosion loss; (2) moderate amounts of erosion occur near the end of the scroll and on a few of the nozzle blades near this location. Results are presented in the form of surface contours that exist on the scroll and blade surfaces after continuous particulate ingestion with time.

Tree species and functional traits but not species richness affect interrill erosion processes in young subtropical forests

NASA Astrophysics Data System (ADS)

Seitz, S.; Goebes, P.; Song, Z.; Bruelheide, H.; Härdtle, W.; Kühn, P.; Li, Y.; Scholten, T.

2016-01-01

Soil erosion is seriously threatening ecosystem functioning in many parts of the world. In this context, it is assumed that tree species richness and functional diversity of tree communities can play a critical role in improving ecosystem services such as erosion control. An experiment with 170 micro-scale run-off plots was conducted to investigate the influence of tree species and tree species richness as well as functional traits on interrill erosion in a young forest ecosystem. An interrill erosion rate of 47.5 Mg ha-1 a-1 was calculated. This study provided evidence that different tree species affect interrill erosion differently, while tree species richness did not affect interrill erosion in young forest stands. Thus, different tree morphologies have to be considered, when assessing soil erosion under forest. High crown cover and leaf area index reduced interrill erosion in initial forest ecosystems, whereas rising tree height increased it. Even if a leaf litter cover was not present, the remaining soil surface cover by stones and biological soil crusts was the most important driver for soil erosion control. Furthermore, soil organic matter had a decreasing influence on interrill erosion. Long-term monitoring of soil erosion under closing tree canopies is necessary, and a wide range of functional tree traits should be considered in future research.

Rinsing with antacid suspension reduces hydrochloric acid-induced erosion.

PubMed

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.

Development of a statistical model for the determination of the probability of riverbank erosion in a Meditteranean river basin

NASA Astrophysics Data System (ADS)

Varouchakis, Emmanouil; Kourgialas, Nektarios; Karatzas, George; Giannakis, Georgios; Lilli, Maria; Nikolaidis, Nikolaos

2014-05-01

the independent variables tested (Atkinson et al. 2003). The developed statistical model is applied to the Koiliaris River Basin in the island of Crete, Greece. The aim is to determine the probability of erosion along the Koiliaris' riverbanks considering a series of independent geomorphological and/or hydrological variables. Data for the river bank slope and for the river cross section width are available at ten locations along the river. The riverbank has indications of erosion at six of the ten locations while four has remained stable. Based on a recent work, measurements for the two independent variables and data regarding bank stability are available at eight different locations along the river. These locations were used as validation points for the proposed statistical model. The results show a very close agreement between the observed erosion indications and the statistical model as the probability of erosion was accurately predicted at seven out of the eight locations. The next step is to apply the model at more locations along the riverbanks. In November 2013, stakes were inserted at selected locations in order to be able to identify the presence or absence of erosion after the winter period. In April 2014 the presence or absence of erosion will be identified and the model results will be compared to the field data. Our intent is to extend the model by increasing the number of independent variables in order to indentify the key factors favouring erosion along the Koiliaris River. We aim at developing an easy to use statistical tool that will provide a quantified measure of the erosion probability along the riverbanks, which could consequently be used to prevent erosion and flooding events. Atkinson, P. M., German, S. E., Sear, D. A. and Clark, M. J. 2003. Exploring the relations between riverbank erosion and geomorphological controls using geographically weighted logistic regression. Geographical Analysis, 35 (1), 58-82. Luppi, L., Rinaldi, M., Teruggi, L. B

Human induced prehistoric and historical soil erosion and landscape development in Southwestern USA

NASA Astrophysics Data System (ADS)

Dotterweich, Markus; Ivester, Andrew H.; Hanson, Paul R.; Daniel, Larsen; Dye, David H.; Foster, Thomas H., II

2015-04-01

The significance of soil erosion due to pre-historic land use and possible feedback mechanisms had been hardly recognized in the Southeastern USA. Here, the agricultural practices only began in the second half of the Holocene. Sedentary hunters and gatherers started to domesticate squash and sunflowers. Associated with the expansion of maize cultivation in the Mississippian period between AD 800 and 1100, significant forest clearings took place on the river floodplains. During this time, central settlements with up to 30,000 residences existed and the surrounding ridge and furrow fields extended to up to 30 ha. It is still open to question why these groups already declined in the 14/15th centuries already before the arrival of the Europeans. However, around AD 1540 the conquistador de Soto still reports extended fields with intensive cultivation of maize in the uplands of Northern Mississippi. Despite of this intensive land use by Native Americans, current research gives no indication that these activities had any significant impact on river channel form. Also, no clear evidence exists for distinct channel change occurring in response to any sort of middle Holocene Hypsithermal, Medieval warm period, or the Little Ice Age. We will present results of a project which aims to explore erosion forms, colluvial sediments and buried soils in selected 0-order and 1st-order watersheds in the southeastern USA in order to gain, solidify, and evaluate general data on soil erosion during the Native American land use period and its respective long-term effects on the environment. This will be achieved by 1) recording the stratigraphy of colluvial and alluvial sediments and buried soils, 2) mapping the extent of erosional and colluvial forms, 3) analyzing chemical and physical soil and sediment properties, 4) establishing chronological control using various dating techniques including radiocarbon and OSL dating, and 5) quantifying soil erosion using hillslope sediments. The

Non-motorized winter recreation impacts to snowmelt erosion, Tronsen Basin, Eastern Cascades, Washington.

PubMed

Eagleston, Holly; Rubin, Charles

2013-01-01

Many recreation impact studies have focused on summer activities, but the environmental impact of winter recreation is poorly characterized. This study characterizes the impact of snowshoe/cross-country ski compaction and snowmelt erosion on trails. Trail cross-sectional profiles were measured before and after the winter season to map changes in erosion due to winter recreation. Compacted snow on the trail was 30 % more dense than snowpack off the trail before spring melt out. Snow stayed on the trail 7 days longer. Soil and organic material was transported after spring snowmelt with -9.5 ± 2.4 cm(2) total erosion occurring on the trail transects and -3.8 ± 2.4 cm(2) total erosion occurring on the control transect (P = 0.046). More material was transported on the trail than on the control, 12.9± 2.4 versus 6.0 ± 2.4 cm(2) (P = 0.055), however, deposition levels remained similar on the trail and on the control. Snow compaction from snowshoers and cross-country skiers intensified erosion. Trail gradient was found to be significantly correlated to net changes in material on the trail (R (2) = 0.89, ρ = -0.98, P = 0.005). This study provides a baseline, showing that non-motorized winter recreation does impact soil erosion rates but more studies are needed. Trail managers should consider mitigation such as water bars, culverts and avoiding building trails with steep gradients, in order to reduce loss of soils on trails and subsequent sedimentation of streams.

Non-motorized Winter Recreation Impacts to Snowmelt Erosion, Tronsen Basin, Eastern Cascades, Washington

NASA Astrophysics Data System (ADS)

Eagleston, Holly; Rubin, Charles

2013-01-01

Many recreation impact studies have focused on summer activities, but the environmental impact of winter recreation is poorly characterized. This study characterizes the impact of snowshoe/cross-country ski compaction and snowmelt erosion on trails. Trail cross-sectional profiles were measured before and after the winter season to map changes in erosion due to winter recreation. Compacted snow on the trail was 30 % more dense than snowpack off the trail before spring melt out. Snow stayed on the trail 7 days longer. Soil and organic material was transported after spring snowmelt with -9.5 ± 2.4 cm2 total erosion occurring on the trail transects and -3.8 ± 2.4 cm2 total erosion occurring on the control transect ( P = 0.046). More material was transported on the trail than on the control, 12.9± 2.4 versus 6.0 ± 2.4 cm2 ( P = 0.055), however, deposition levels remained similar on the trail and on the control. Snow compaction from snowshoers and cross-country skiers intensified erosion. Trail gradient was found to be significantly correlated to net changes in material on the trail ( R 2 = 0.89, ρ = -0.98, P = 0.005). This study provides a baseline, showing that non-motorized winter recreation does impact soil erosion rates but more studies are needed. Trail managers should consider mitigation such as water bars, culverts and avoiding building trails with steep gradients, in order to reduce loss of soils on trails and subsequent sedimentation of streams.

Assessment of mercury erosion by surface water in Wanshan mercury mining area.

PubMed

Dai, ZhiHui; Feng, Xinbin; Zhang, Chao; Shang, Lihai; Qiu, Guangle

2013-08-01

Soil erosion is a main cause of land degradation, and in its accelerated form is also one of the most serious ecological environmental problems. Moreover, there are few studies on migration of mercury (Hg) induced by soil erosion in seriously Hg-polluted districts. This paper selected Wanshan Hg mining area, SW China as the study area. Revised universal soil loss equation (RUSLE) and Geographic information system (GIS) methods were applied to calculate soil and Hg erosion and to classify soil erosion intensity. Our results show that the soil erosion rate can reach up to 600,884tkm(-2)yr(-1). Surfaces associated with very slight and extremely severe erosion include 76.6% of the entire land in Wanshan. Furthermore, the cumulative erosion rates in the area impacted by extremely severe erosion make up 90.5% of the total. On an annual basis, Hg surface erosion load was predicted to be 505kgyr(-1) and the corresponding mean migration flux of Hg was estimated to be 3.02kgkm(-2)yr(-1). The erosion loads of Hg resulting from farmland and meadow soil were 175 and 319kgyr(-1) respectively, which were enhanced compared to other landscape types due to the fact that they are generally located in the steep zones associated with significant reclamation. Contributing to establish a mass balance of Hg in Wanshan Hg mining area, this study supplies a dependable scientific basis for controlling soil and water erosion in the local ecosystems. Land use change is the most effective way for reducing Hg erosion load in Wanshan mining area. Copyright © 2013 Elsevier Inc. All rights reserved.

[Sediment-yielding process and its mechanisms of slope erosion in wind-water erosion crisscross region of Loess Plateau, Northwest China].

PubMed

Tuo, Deng-Feng; Xu, Ming-Xiang; Zheng, Shi-Qing; Li, Qiang

2012-12-01

Due to the coupling effects of wind and water erosions in the wind-water erosion crisscross region of Loess Plateau, the slope erosion in the region was quite serious, and the erosion process was quite complicated. By using wind tunnel combined with simulated rainfall, this paper studied the sediment-yielding process and its mechanisms of slope erosion under the effects of wind-water alternate erosion, and quantitatively analyzed the efffects of wind erosion on water erosion and the relationships between wind and water erosions. There was an obvious positive interaction between wind and water erosions. Wind erosion promoted the development of microtopography, and altered the quantitative relationship between the sediment-yielding under water erosion and the variation of rainfall intensity. At the rainfall intensity of 60 and 80 mm x h(-1), the sediment-yielding without wind erosion decreased with the duration of rainfall and tended to be stable, but the sediment-yielding with wind erosion decreased to a certain valley value first, and then showed an increasing trend. At the rainfall intensity of 60, 80, and 100 mm x h(-1), the sediment-yielding with the wind erosion at speeds of 11 and 14 m x s(-1) increased by 7.3%-27.9% and 23.2%-39.0%, respectively, as compared with the sediment-yielding without wind erosion. At the rainfall intensity of 120 and 150 mm x h(-1) and in the rainfall duration of 15 minutes, the sediment-yielding with and without wind erosion presented a decreasing trend, but, with the increase of rainfall duration, the sediment-yielding with wind erosion showed a trend of decreasing first and increasing then, as compared with the sediment-yielding without wind erosion. The mechanisms of wind-water alternate erosion were complicated, reflecting in the mutual relation and mutual promotion of wind erosion and water erosion in the aspects of temporal-spatial distribution, energy supply, and action mode of erosion forces.

A Statistical Project Control Tool for Engineering Managers

NASA Technical Reports Server (NTRS)

Bauch, Garland T.

2001-01-01

This slide presentation reviews the use of a Statistical Project Control Tool (SPCT) for managing engineering projects. A literature review pointed to a definition of project success, (i.e., A project is successful when the cost, schedule, technical performance, and quality satisfy the customer.) The literature review also pointed to project success factors, and traditional project control tools, and performance measures that are detailed in the report. The essential problem is that with resources becoming more limited, and an increasing number or projects, project failure is increasing, there is a limitation of existing methods and systematic methods are required. The objective of the work is to provide a new statistical project control tool for project managers. Graphs using the SPCT method plotting results of 3 successful projects and 3 failed projects are reviewed, with success and failure being defined by the owner.

Comparison of Atomic Oxygen Erosion Yields of Materials at Various Energy and Impact Angles

NASA Technical Reports Server (NTRS)

Banks, Bruce A.; Waters, Deborah L.; Thorson, Stephen D.; deGroh, Kim, K.; Snyder, Aaron; Miller, Sharon

2006-01-01

The atomic oxygen erosion yields of various materials, measured in volume of material oxidized per incident atomic oxygen atom, are compared to the commonly accepted standard of Kapton H (DuPont) polyimide. The ratios of the erosion yield of Kapton H to the erosion yield of various materials are not consistent at different atomic oxygen energies. Although it is most convenient to use isotropic thermal energy RF plasma ashers to assess atomic oxygen durability, the results can be misleading because the relative erosion rates at thermal energies are not necessarily the same as low Earth orbital (LEO) energies of approx.4.5 eV. An experimental investigation of the relative atomic oxygen erosion yields of a wide variety of polymers and carbon was conducted using isotropic thermal energy (approx.0.1 eV) and hyperthermal energy (approx.70 eV) atomic oxygen using an RF plasma asher and an end Hall ion source. For hyperthermal energies, the atomic oxygen erosion yields relative to normal incident Kapton H were compared for sweeping atomic oxygen arrival with that of normal incidence arrival. The results of isotropic thermal energy, normal incident, and sweeping incident atomic oxygen are also compared with measured or projected LEO values.

A new methodology for hydro-abrasive erosion tests simulating penstock erosive flow

NASA Astrophysics Data System (ADS)

Aumelas, V.; Maj, G.; Le Calvé, P.; Smith, M.; Gambiez, B.; Mourrat, X.

2016-11-01

Hydro-abrasive resistance is an important property requirement for hydroelectric power plant penstock coating systems used by EDF. The selection of durable coating systems requires an experimental characterization of coating performance. This can be achieved by performing accelerated and representative laboratory tests. In case of severe erosion induced by a penstock flow, there is no suitable method or standard representative of real erosive flow conditions. The presented study aims at developing a new methodology and an associated laboratory experimental device. The objective of the laboratory apparatus is to subject coated test specimens to wear conditions similar to the ones generated at the penstock lower generatrix in actual flow conditions. Thirteen preselected coating solutions were first been tested during a 45 hours erosion test. A ranking of the thirteen coating solutions was then determined after characterisation. To complete this first evaluation and to determine the wear kinetic of the four best coating solutions, additional erosion tests were conducted with a longer duration of 216 hours. A comparison of this new method with standardized tests and with real service operating flow conditions is also discussed. To complete the final ranking based on hydro-abrasive erosion tests, some trial tests were carried out on penstock samples to check the application method of selected coating systems. The paper gives some perspectives related to erosion test methodologies for materials and coating solutions for hydraulic applications. The developed test method can also be applied in other fields.

Prevalence and risk factors of dental erosion in American children.

PubMed

Habib, Mariam; Hottel, Timothy L; Hong, Liang

2013-01-01

The purpose of this study was to assess the prevalence and characteristics of dental erosion in children aged 2-4 years old and 12 years old. 243 subjects were recruited from daycare centers, preschools, and grade schools; they received dental examinations assessing their condition of dental erosion, including both depth and area of tooth surface loss on four maxillary incisors. Questionnaires were given to the subjects to obtain socio-demographic, oral health behaviors at home, and access to dental care. Dental erosion was analyzed and risk factors were assessed using Chi-Square and logistic regression analysis. The subjects were 60% Caucasians, 31% Black, 7% Hispanic and others were 2%. 34% of children could not get the dental care they needed within the past 12 months and 61% of all children brushed their teeth twice or more daily. Overall, 12% of study children had dental erosion with 13% for 2-4 years old and 10% for 12 years old, with the majority of erosive lesions within enamel. Family income (OR 3.98, p = 0.021) and acidic fruit juice consumption (OR 2.38, p = 0.038) were significant risk factors for dental erosion, even after controlling for other factors, such as source of drinking water and oral hygiene using logistic regression analysis. Dental erosion is a relatively common problem among the children in this study and it is seen as a multi-factorial process.

Reassessment of soil erosion on the Chinese loess plateau: were rates overestimated?

NASA Astrophysics Data System (ADS)

Zhao, Jianlin; Govers, Gerard

2014-05-01

in significantly higher erodibility values than those obtained from field data. Overestimations of the P and LS factors are mainly due to the fact that erosion control measures such as terracing are not accounted for and that erroneous scaling functions are used on permanently vegetated areas. Our findings have not only important implications with respect to the mobilization of sediments by agricultural erosion: we will also need to reassess the impact of erosion on biogeochemicaly cycling and crop productivity. Fu, B., Liu, Y., Lü, Y., He, C., Zeng, Y., & Wu, B. (2011). Assessing the soil erosion control service of ecosystems change in the Loess Plateau of China. Ecological Complexity, 8(4), 284-293. doi:10.1016/j.ecocom.2011.07.003 Nearing, M. A. (1997). A single, continuous function for slope steepness influence on soil loss. Soil Science Society of American Journal, 61(3), 917-919. Quinton, J. N., Govers, G., Van Oost, K., & Bardgett, R. D. (2010). The impact of agricultural soil erosion on biogeochemical cycling. Nature Geoscience, 3(5), 311-314. doi:10.1038/ngeo838 Sun, W., Shao, Q., & Liu, J. (2013). Soil erosion and its response to the changes of precipitation and vegetation cover on the Loess Plateau. Journal of Geographical Sciences, 23(6), 1091-1106. doi:10.1007/s11442-013-1065-z

Optical Boron Nitride Insulator Erosion Characterization of a 200 W Xenon Hall Thruster

DTIC Science & Technology

2005-05-01

Hall thruster boron nitride insulator is evaluated as a diagnostic for real-time evaluation of thruster insulator erosion. Three Hall thruster plasma control variables are examined: ion energy (discharge potential), ion flux (propellant flow), and plasma conductivity (magnetic field strength). The boron emission, and hence the insulator erosion rate, varies linearly with ion energy and ion flux. A minimum erosion rate appears at intermediate magnetic field strengths. This may indicate that local plasma conductivity significantly affects the divergence

Advances in soil erosion modelling through remote sensing data availability at European scale

NASA Astrophysics Data System (ADS)

Panagos, Panos; Karydas, Christos; Borrelli, Pasqualle; Ballabio, Cristiano; Meusburger, Katrin

2014-08-01

Under the European Union's Thematic Strategy for Soil Protection, the European Commission's Directorate-General for the Environment (DG Environment) has identified the mitigation of soil losses by erosion as a priority area. Policy makers call for an overall assessment of soil erosion in their geographical area of interest. They have asked that risk areas for soil erosion be mapped under present land use and climate conditions, and that appropriate measures be taken to control erosion within the legal and social context of natural resource management. Remote sensing data help to better assessment of factors that control erosion, such as vegetation coverage, slope length and slope angle. In this context, the data availability of remote sensing data during the past decade facilitates the more precise estimation of soil erosion risk. Following the principles of the Universal Soil Loss Equation (USLE), various options to calculate vegetative cover management (C-factor) have been investigated. The use of the CORINE Land Cover dataset in combination with lookup table values taken from the literature is presented as an option that has the advantage of a coherent input dataset but with the drawback of static input. Recent developments in the Copernicus programme have made detailed datasets available on land cover, leaf area index and base soil characteristics. These dynamic datasets allow for seasonal estimates of vegetation coverage, and their application in the G2 soil erosion model which represents a recent approach to the seasonal monitoring of soil erosion. The use of phenological datasets and the LUCAS land use/cover survey are proposed as auxiliary information in the selection of the best methodology.

Dimensionless erosion laws for cohesive sediment

USGS Publications Warehouse

Walder, Joseph S.

2016-01-01

A method of achieving a dimensionless collapse of erosion-rate data for cohesive sediments is proposed and shown to work well for data collected in flume-erosion tests on mixtures of sand and mud (silt plus clay sized particles) for a wide range of mud fraction. The data collapse corresponds to a dimensional erosion law of the form E∼(τ−τc)m">E∼(τ−τc)mE∼(τ−τc)m, where E">EE is erosion rate, τ">ττ is shear stress, τc">τcτc is the threshold shear stress for erosion to occur, and m≈7/4">m≈7/4m≈7/4. This result contrasts with the commonly assumed linear erosion law E=kd(τ−τc)">E=kd(τ−τc)E=kd(τ−τc), where kd">kdkd is a measure of how easily sediment is eroded. The data collapse prompts a re-examination of the way that results of the hole-erosion test (HET) and jet-erosion test (JET) are customarily analyzed, and also calls into question the meaningfulness not only of proposed empirical relationships between kd">kdkd and τc">τcτc, but also of the erodibility parameter kd">kdkd itself. Fuller comparison of flume-erosion data with hole-erosion and jet-erosion data will require revised analyses of the HET and JET that drop the assumption m=1">m=1m=1 and, in the case of the JET, certain simplifying assumptions about the mechanics of jet scour.

Influence of bioadhesive polymers on the protective effect of fluoride against erosion.

PubMed

Ávila, Daniele Mara da Silva; Zanatta, Rayssa Ferreira; Scaramucci, Tais; Aoki, Idalina Vieira; Torres, Carlos Rocha Gomes; Borges, Alessandra Bühler

2017-01-01

This study investigated if the incorporation of the bioadhesive polymers Carbopol 980, Carboxymethyl cellulose (CMC), and Aristoflex AVC in a fluoridated solution (NaF-900ppm) would increase the solution's protective effect against enamel erosion. Enamel specimens were submitted to a 5-day de-remineralization cycling model, consisting of 2min immersions in 0.3% citric acid (6x/day), 1min treatments with the polymers (associated or not with fluoride), and 60min storage in artificial saliva. Ultrapure water was used as the negative control and a 900ppm fluoride solution as positive control. The initial Knoop microhardness (KHN1) was used to randomize the samples into groups. Another two microhardness assessments were performed after the first (KHN2) and second (KHN3) acid immersions, to determine initial erosion in the first day. The formula: %KHN alt =[(KHN3-KHN2)/KHN2]*100 was used to define the protective effect of the treatments. After the 5-day cycling, surface loss (SL, in μm) was evaluated with profilometry. Data were analyzed with 2-way ANOVA and Tukey's tests (p<0.05). For %KHN alt , the polymers alone did not reduce enamel demineralization when compared to the negative control, but Carbopol associated with NaF significantly improved its protective effect. The profilometric analysis showed that Carbopol, associated or not with NaF, exhibited the lowest SL, while CMC and Aristoflex did not exhibit a protective effect, nor were they able to improve the protection of NaF. It is concluded that Carbopol enhanced NaF's protection against initial erosion. Carbopol alone or associated with NaF was able to reduce SL after several erosive challenges. Carbopol by itself was able to reduce the erosive wear magnitude to the same extent as the sodium fluoride, therefore, is a promising agent to prevent or control enamel erosion. Copyright © 2016 Elsevier Ltd. All rights reserved.

In situ effect of CPP-ACP chewing gum upon erosive enamel loss

PubMed Central

de ALENCAR, Catarina Ribeiro Barros; de OLIVEIRA, Gabriela Cristina; MAGALHÃES, Ana Carolina; BUZALAF, Marília Afonso Rabelo; MACHADO, Maria Aparecida de Andrade Moreira; HONÓRIO, Heitor Marques; RIOS, Daniela

2017-01-01

Abstract Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) is able to increase salivary calcium and phosphate levels at an acidic pH. Previous studies demonstrated that a CPP-ACP chewing gum was able to enhance the re-hardening of erosion lesions, but could not diminish enamel hardness loss. Therefore, there is no consensus regarding the effectiveness of CPP-ACP on dental erosion. Objective This in situ study investigated the ability of a CPP-ACP chewing gum in preventing erosive enamel loss. Material and Methods: During three experimental crossover phases (one phase per group) of seven days each, eight volunteers wore palatal devices with human enamel blocks. The groups were: GI – Sugar free chewing gum with CPP-ACP; GII – Conventional sugar free chewing gum; and GIII – No chewing gum (control). Erosive challenge was extraorally performed by immersion of the enamel blocks in cola drink (5 min, 4x/day). After each challenge, in groups CPP and No CPP, volunteers chewed one unit of the corresponding chewing gum for 30 minutes. Quantitative analysis of enamel loss was performed by profilometry (µm). Data were analyzed by Repeated-Measures ANOVA and Tukey’s test (p<0.05). Results The use of chewing gum (CPP and No CPP) resulted in lower erosive enamel loss compared with the control group (p<0.05). CPP-ACP chewing gum (CPP) did not improve the protection against erosive enamel loss compared with conventional chewing gum (No CPP) (p>0.05). Conclusion The CPP-ACP chewing gum was not able to enhance the anti-erosive effect of conventional chewing gum against enamel loss. PMID:28678944

Keeping soil in the field - runoff and erosion management in asparagus crops

NASA Astrophysics Data System (ADS)

Niziolomski, Joanna; Simmons, Robert; Rickson, Jane; Hann, Mike

2016-04-01

Row crop production (including potatoes, onions, carrots, asparagus, bulbs and lettuce) is regarded as one of the most erosive agricultural cropping systems. This is a result of the many practices involved that increase erosion risk including: fine seedbed preparation, a typically short growing season where adequate ground cover protects the soil, permanent bare soil areas between crops, and often intensive harvesting methods that can damage soil structure and result in soil compaction. Sustained exposure of bare soil coupled with onsite compaction on slightly sloping land results in soil and water issues in asparagus production. Asparagus production is a growing British industry covering > 2000 ha and is worth approximately £30 million yr-1. However, no tried and tested erosion control measurements currently exist to manage associated problems. Research has recently been undertaken investigating the effectiveness of erosion control measures suitable for asparagus production systems. These consisted of surface applied wheat straw mulch and shallow soil disturbance (< 350 mm) using several tine configurations: a currently adopted winged tine, a narrow with two shallow leading tines, and a modified para-plough. These treatments were tested individually and in combination (straw mulch with each shallow soil disturbance tine configuration) using triplicated field plots situated on a working asparagus farm in Herefordshire, UK. Testing was conducted between May and November 2013. Rainfall-event based runoff and erosion measurements were taken including; runoff volume, runoff rate and total soil loss. Runoff and soil erosion was observed from all treatments. However, the surface application of straw mulch alone out performed each shallow soil disturbance practice. This suggests that runoff and erosion from asparagus production can be reduced using the simple surface application of straw.

Erosion rates of wood during natural weathering. Part II, Earlywood and latewood erosion rates

Treesearch

R. Sam Williams; Mark T. Knaebe; William C. Feist

2001-01-01

This is the second in a series of reports on the erosion rates of wood exposed outdoors near Madison, Wisconsin. In the work reported here, the erosion rates of earlywood and latewood were determined for smooth-planed vertical-grained lumber for an exposure period of 14 years. The specimens were oriented vertically, facing south; erosion was measured annually for the...

Impact of cornstalk buffer strip on hillslope soil erosion and its hydrodynamic understanding

USDA-ARS?s Scientific Manuscript database

Soil erosion is still a serious concern on the Loess Plateau despite extensive soil conservation measures. Cornstalk buffer strip is not well utilized on the Loess Plateau, and there is little information on the hydrodynamic understanding of this soil erosion control practice. A simulated rainfall e...

Soil Erosion: Quiet Crisis in the World Economy. Worldwatch Paper 60.

ERIC Educational Resources Information Center

Brown, Lester R.; Wolf, Edward C.

Although soil erosion is a natural process, it has increased to the point where it far exceeds the natural formation of new soil. However, with only occasional exceptions, national agricultural and population policies have failed to take soil depletion into account. Projections of world food production always incorporate estimates of future…

Mapping monthly rainfall erosivity in Europe.

PubMed

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 -1 h -1 ) compared to winter (87MJmmha -1 h -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 R 2 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

Reconciling water harvesting and soil erosion control by thoughtful implementation of SWC measures

NASA Astrophysics Data System (ADS)

Bellin, N.; Vanacker, V.; van Wesemael, B.

2012-04-01

-agricultural catchments have been found only partially filled with sediments. Extensive reforestation programs, recovery of natural vegetation (dense matorral) and abandonment of agricultural fields in the Sierras led to a strong reduction of the sediment transport towards the river system. Although the effect of the check dams on the transport of sediment has not been important, the check dams have played a major role in flood control in the area. Our data indicate that thoughtful design of SWC schemes is necessary to reconcile water harvesting, erosion mitigation and flood control. Currently, the erosion hotspots are clearly localized in the agricultural fields, and not in the marginal lands in the Sierras. The combination of on-site and off-site SWC measures in the agricultural areas is highly efficient to reduce fluxes of sediment and surface water.

Pore water effects on soil erodibility and its implication in ephemeral gully erosion modeling

USDA-ARS?s Scientific Manuscript database

Ephemeral gully erosion is the main source of sediment from the agricultural landscape, unfortunately, it has been overlooked in traditional soil erosion assessment. Field observations, and subsequent support from controlled lab experiments, have shown the linkage between transient soil hydraulic co...

The effect of magnesium hydroxide-containing dentifrice using an extrinsic and intrinsic erosion cycling model.

PubMed

Passos, Vanara Florêncio; Rodrigues, Lidiany Karla Azevedo; Santiago, Sérgio Lima

2018-02-01

To evaluate, in vitro, the effect of Mg(OH) 2 dentifrice, and the influence of the number of experimental days, on the extrinsic (citric acid -CA) and intrinsic (hydrochloric acid -HCl) enamel erosion models. Human enamel slabs were selected according to surface hardness and randomly assigned to 3 groups (n=9) as follows: non-fluoridated (negative control), NaF (1450ppm F- positive control) and Mg(OH) 2 (2%) dentifrices. The slabs were daily submitted to a 2-h period of pellicle formation and, over a period of 5days, submitted to cycles (3×/day) of erosive challenge (CA 0.05M, pH=3.75 or HCl 0.01M, pH=2 for 30s), treatment (1min -1:3w/w of dentifrice/distilled water) and remineralization (artificial saliva/120min). Enamel changes were determined by surface hardness loss (SHL) for each day and mechanical profilometry analysis. Data were analyzed by two-way ANOVA followed by Tukey's test to % SHL and one-way ANOVA to profilometry (p<0.05). The number of experimental days influenced the erosion process for the two types of erosion models (p<0.001). Mg(OH) 2 -containing dentifrices were effective in reducing enamel extrinsic acid erosion as determined by % SHL (p<0.001) when compared to the control group, being better than positive control (p<0.001); however, the dentifrices were not effective for the intrinsic model (p=0.295). With regards to surface wear, no statistically significant differences were found among the groups for CA (p=0.225) and HCl (p=0.526). The findings suggest that Mg(OH) 2 dentifrices might protect enamel against slight erosion, but protection was not effective for stronger acid erosion. Copyright © 2017 Elsevier Ltd. All rights reserved.

Erosion and abrasion on dental structures undergoing at-home bleaching

PubMed Central

Demarco, Flávio Fernando; Meireles, Sônia Saeger; Sarmento, Hugo Ramalho; Dantas, Raquel Venâncio Fernandes; Botero, Tatiana; Tarquinio, Sandra Beatriz Chaves

2011-01-01

This review investigates erosion and abrasion in dental structures undergoing at- home bleaching. Dental erosion is a multifactorial condition that may be idiopathic or caused by a known acid source. Some bleaching agents have a pH lower than the critical level, which can cause changes in the enamel mineral content. Investigations have shown that at-home tooth bleaching with low concentrations of hydrogen or carbamide peroxide have no significant damaging effects on enamel and dentin surface properties. Most studies where erosion was observed were in vitro. Even though the treatment may cause side effects like sensitivity and gingival irritation, these usually disappear at the end of treatment. Considering the literature reviewed, we conclude that tooth bleaching agents based on hydrogen or carbamide peroxide have no clinically significant influence on enamel/dentin mineral loss caused by erosion or abrasion. Furthermore, the treatment is tolerable and safe, and any adverse effects can be easily reversed and controlled. PMID:23674914

Soil coverage evolution and wind erosion risk on summer crops under contrasting tillage systems

NASA Astrophysics Data System (ADS)

Mendez, Mariano J.; Buschiazzo, Daniel E.

2015-03-01

The effectiveness of wind erosion control by soil surface conditions and crop and weed canopy has been well studied in wind tunnel experiments. The aim of this study is to assess the combined effects of these variables under field conditions. Soil surface conditions, crop and weed coverage, plant residue, and non-erodible aggregates (NEA) were measured in the field between the fallow start and the growth period of sunflower (Helianthus annuus) and corn (Zea mays). Both crops were planted on a sandy-loam Entic Haplustoll with conventional-(CT), vertical-(VT) and no-till (NT) tillage systems. Wind erosion was estimated by means of the spreadsheet version the Revised Wind Erosion Equation and the soil coverage was measured each 15 days. Results indicated that wind erosion was mostly negligible in NT, exceeding the tolerable levels (estimated between 300 and 1400 kg ha-1 year-1 by Verheijen et al. (2009)) only in an year with high climatic erosivity. Wind erosion exceeded the tolerable levels in most cases in CT and VT, reaching values of 17,400 kg ha-1. Wind erosion was 2-10 times higher after planting of both crops than during fallows. During the fallows, the soil was mostly well covered with plant residues and NEA in CT and VT and with residues and weeds in NT. High wind erosion amounts occurring 30 days after planting in all tillage systems were produced by the destruction of coarse aggregates and the burying of plant residues during planting operations and rains. Differences in soil protection after planting were given by residues of previous crops and growing weeds. The growth of weeds 2-4 weeks after crop planting contributed to reduce wind erosion without impacting in crops yields. An accurate weeds management in semiarid lands can contribute significantly to control wind erosion. More field studies are needed in order to develop management strategies to reduce wind erosion.

Device Oriented Project Controller

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dalesio, Leo; Kraimer, Martin

2013-11-20

This proposal is directed at the issue of developing control systems for very large HEP projects. A de-facto standard in accelerator control is the Experimental Physics and Industrial Control System (EPICS), which has been applied successfully to many physics projects. EPICS is a channel based system that requires that each channel of each device be configured and controlled. In Phase I, the feasibility of a device oriented extension to the distributed channel database was demonstrated by prototyping a device aware version of an EPICS I/O controller that functions with the current version of the channel access communication protocol. Extensions havemore » been made to the grammar to define the database. Only a multi-stage position controller with limit switches was developed in the demonstration, but the grammar should support a full range of functional record types. In phase II, a full set of record types will be developed to support all existing record types, a set of process control functions for closed loop control, and support for experimental beam line control. A tool to configure these records will be developed. A communication protocol will be developed or extensions will be made to Channel Access to support introspection of components of a device. Performance bench marks will be made on both communication protocol and the database. After these records and performance tests are under way, a second of the grammar will be undertaken.« less

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

NASA Astrophysics Data System (ADS)

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

Toothpastes and enamel erosion/abrasion - Impact of active ingredients and the particulate fraction.

PubMed

Ganss, C; Marten, J; Hara, A T; Schlueter, N

2016-11-01

To investigate in vitro a range of differently characterised toothpastes with respect to their efficacy in an erosion/abrasion setting with special emphasis on the role of the particulate ingredients. Human enamel samples were erosively demineralised with citric acid (2min, 6×/day; 0.5%, pH 2.5; 10 days) and immersed in slurries (2min, 2×/day) either without or with brushing (15s, load 200g). The toothpastes were eight NaF-toothpastes, three hydroxyapatite-toothpastes (one without and two with NaF), one fluoride-free chitosan-toothpaste and three Sn-toothpastes. Negative control was erosion only, positive control was SnF 2 gel. Tissue loss was quantified profilometrically. The SnF 2 gel was most effective (reduction of tissue loss of 79%). Most of the products reduced tissue loss significantly when applied as slurries (between 28 and 66%). Brushing increased tissue loss in almost all toothpastes, only 5 formulations (all Sn-toothpastes and 2 NaF-toothpastes) reduced tissue loss significantly when compared to negative control (between 33 and 59%). There was a non-linear association between abrasiveness and amount of particles in a formulation, the particle size had no impact. Toothpastes had a protecting effect when applied as slurries but to a much lesser degree when applied with brushing. The particulate fraction may be a determinant for toothpaste efficacy in erosion/abrasion settings. Toothpastes are important carriers of active agents against erosion, but physical impacts through brushing modifies efficacy distinctly. Understanding the role of the particulate fraction in toothpastes may offer perspectives for designing effective formulations for patients with erosive lesions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Process-oriented modelling to identify main drivers of erosion-induced carbon fluxes

NASA Astrophysics Data System (ADS)

Wilken, Florian; Sommer, Michael; Van Oost, Kristof; Bens, Oliver; Fiener, Peter

2017-05-01

Coupled modelling of soil erosion, carbon redistribution, and turnover has received great attention over the last decades due to large uncertainties regarding erosion-induced carbon fluxes. For a process-oriented representation of event dynamics, coupled soil-carbon erosion models have been developed. However, there are currently few models that represent tillage erosion, preferential water erosion, and transport of different carbon fractions (e.g. mineral bound carbon, carbon encapsulated by soil aggregates). We couple a process-oriented multi-class sediment transport model with a carbon turnover model (MCST-C) to identify relevant redistribution processes for carbon dynamics. The model is applied for two arable catchments (3.7 and 7.8 ha) located in the Tertiary Hills about 40 km north of Munich, Germany. Our findings indicate the following: (i) redistribution by tillage has a large effect on erosion-induced vertical carbon fluxes and has a large carbon sequestration potential; (ii) water erosion has a minor effect on vertical fluxes, but episodic soil organic carbon (SOC) delivery controls the long-term erosion-induced carbon balance; (iii) delivered sediments are highly enriched in SOC compared to the parent soil, and sediment delivery is driven by event size and catchment connectivity; and (iv) soil aggregation enhances SOC deposition due to the transformation of highly mobile carbon-rich fine primary particles into rather immobile soil aggregates.

Innovative In-Situ Remediation of Contaminated Sediments for Simultaneous Control of Contamination and Erosion. Part 1

DTIC Science & Technology

2011-08-01

Measurements of Sediment Erosion Rates and Critical Shear Stress ......................... 45 Erosion Rate Ratio Analysis...chromatography ICP-MS – inductively coupled plasma – mass spectrometry Kd – partition coefficient Meq – milliequivalents MNR – monitored natural...186 Figure 82. Critical Shear Stress Comparison among Biopolymer Materials at 2, 10, and 175 Days. Each

Graffiti for science: Qualitative detection of erosional patterns through bedrock erosion painting

NASA Astrophysics Data System (ADS)

Beer, Alexander R.; Kirchner, James W.; Turowski, Jens M.

2016-04-01

during flushing events. Further, the photographs clearly show the erosional development of a UFCS (upstream-facing convex surface) feature with an upstream-facing surface full of impact marks, a sharp crest-line, and an adjacent downstream-facing surface preserved from sediment impacts. This pilot study documents that bedrock erosion painting provides an easy, cost-efficient and clear qualitative method for detecting the spatial distribution of bedrock erosion and inferring its controlling factors. Our results show that the susceptibility of a painted surface to abrasion is controlled by its position in the channel and its spatial orientation relative to the sediment-laden flow. Erosion painting is a scientifically useful form of graffiti that could be widely applied in both natural and laboratory settings, providing insight into patterns and processes of erosion.

On-site monitoring of construction of Terror Lake hydroelectric project, Kodiak, Alaska. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hosking, H.

The report describes the effort by the Fish and Wildlife Service to monitor the construction of the first hydroelectric project built on national wildlife refuge lands under license by the Federal Energy Regulatory Commission. Recommendations are offered for use in planning other projects. Fish and wildlife species of concern included brown bears, Sitka black-tailed deer, mountain goats, raptors (including bald eagles), and several species of salmonid fish. Construction practices relating to erosion control, contaminant management, culvert placement, and siting of project structures are covered.

An Establishment of Rainfall-induced Soil Erosion Index for the Slope Land in Watershed

NASA Astrophysics Data System (ADS)

Tsai, Kuang-Jung; Chen, Yie-Ruey; Hsieh, Shun-Chieh; Shu, Chia-Chun; Chen, Ying-Hui

2014-05-01

With more and more concentrated extreme rainfall events as a result of climate change, in Taiwan, mass cover soil erosion occurred frequently and led to sediment related disasters in high intensity precipiton region during typhoons or torrential rain storms. These disasters cause a severely lost to the property, public construction and even the casualty of the resident in the affected areas. Therefore, we collected soil losses by using field investigation data from the upstream of watershed where near speific rivers to explore the soil erosion caused by heavy rainfall under different natural environment. Soil losses induced by rainfall and runoff were obtained from the long-term soil depth measurement of erosion plots, which were established in the field, used to estimate the total volume of soil erosion. Furthermore, the soil erosion index was obtained by referring to natural environment of erosion test plots and the Universal Soil Loss Equation (USLE). All data collected from field were used to compare with the one obtained from laboratory test recommended by the Technical Regulation for Soil and Water Conservation in Taiwan. With MATLAB as a modeling platform, evaluation model for soil erodibility factors was obtained by golden section search method, considering factors contributing to the soil erosion; such as degree of slope, soil texture, slope aspect, the distance far away from water system, topography elevation, and normalized difference vegetation index (NDVI). The distribution map of soil erosion index was developed by this project and used to estimate the rainfall-induced soil losses from erosion plots have been established in the study area since 2008. All results indicated that soil erodibility increases with accumulated rainfall amount regardless of soil characteristics measured in the field. Under the same accumulated rainfall amount, the volume of soil erosion also increases with the degree of slope and soil permeability, but decreases with the

Design of a digital holography system for PFC erosion measurements on Proto-MPEX.

PubMed

Thomas, C E Tommy; Biewer, T M; Baylor, L R; Combs, S K; Meitner, S J; Rapp, J; Hillis, D L; Granstedt, E M; Majeski, R; Kaita, R

2016-11-01

A project has been started at ORNL to develop a dual-wavelength digital holography system for plasma facing component erosion measurements on prototype material plasma exposure experiment. Such a system will allow in situ real-time measurements of component erosion. Initially the system will be developed with one laser, and first experimental laboratory measurements will be made with the single laser system. In the second year of development, a second CO 2 laser will be added and measurements with the dual wavelength system will begin. Adding the second wavelength allows measurements at a much longer synthetic wavelength.

[Dental erosion and young adults: what do they know and how would they like to receive information?

PubMed

Verploegen, V J N; Schuller, A A

2017-09-01

Dental erosion occurs often among adolescents and young adults in the Netherlands. This problem requires attention because its consequences are irreversible. In this study (part of the 'Dental Research and Practice in the North Netherlands' project) a questionnaire was distributed to 331 young adults (age 20 to 25) from 25 dental practices. The goal of the study was to find out how much young adults know about dental erosion and how they wish to receive dental information. The results show that much is still unknown about dental erosion among young adults and that the extent of knowledge depended of the level of education and on information on dental erosion that had already been received. Participants preferred to receive information in a conversation with an oral healthcare professional, with the support of printed matter.

Nourishment of perched sand dunes and the issue of erosion control in the Great Lakes

NASA Astrophysics Data System (ADS)

Marsh, William M.

1990-09-01

Although limited in coverage, perched sand dunes situated on high coastal bluffs are considered the most prized of Great Lakes dunes. Grand Sable Dunes on Lake Superior and Sleeping Bear Dunes on Lake Michigan are featured attractions of national lakeshores under National Park Service management. The source of sand for perched dunes is the high bluff along their lakeward edge. As onshore wind crosses the bluff, flow is accelerated upslope, resulting in greatly elevated levels of wind stress over the slope brow. On barren, sandy bluffs, wind erosion is concentrated in the brow zone, and for the Grand Sable Bluff, it averaged 1 m3/yr per linear meter along the highest sections for the period 1973 1983. This mechanism accounts for about 6,500 m3 of sand nourishment to the dunefield annually and clearly has been the predominant mechanism for the long-term development of the dunefield. However, wind erosion and dune nourishment are possible only where the bluff is denuded of plant cover by mass movements and related processes induced by wave erosion. In the Great Lakes, wave erosion and bluff retreat vary with lake levels; the nourishment of perched dunes is favored by high levels. Lake levels have been relatively high for the past 50 years, and shore erosion has become a major environmental issue leading property owners and politicians to support lake-level regulation. Trimming high water levels could reduce geomorphic activity on high bluffs and affect dune nourishment rates. Locally, nourishment also may be influenced by sediment accumulation associated with harbor protection facilities and by planting programs aimed at stabilizing dunes.

Temperature-dependent erosivity of drinks in a model simulating oral fluid dynamics.

PubMed

Steiger-Ronay, Valerie; Steingruber, Andrea; Becker, Klaus; Aykut-Yetkiner, Arzu; Wiedemeier, Daniel B; Attin, Thomas

2018-03-01

Aim of this investigation was to study the temperature-dependent in vitro enamel erosion of five acidic drinks and citric acid under controlled conditions in an artificial mouth. The erosive potential of Orange juice, Coca-Cola Zero, Sprite Zero, two fruit teas and citric acid (control) was investigated on bovine enamel specimens at temperatures between 5 °C and 55 °C. The pH values and total calcium content of all test drinks were determined. Specimens were immersed into an artificial mouth to imitate physiological oral conditions for 60 h. Cyclic de- and re-mineralization was performed, imitating the intake of six drinks in six h followed by a six-hour remineralization phase, where only artificial saliva ran over the specimens. Total erosive enamel loss was determined by contact profilometry. Differences in substance loss at different temperatures were tested for statistical significance (p-values ≤ 0.05) by means of ANOVA. Rising liquid temperature did not result in a considerable change of pH. Highest substance loss was observed for citric acid (33.6 ± 6 μm to 38.7 ± 6 μm), while only little erosion was induced by fruit tea (0.8 ± 1 μm to 5.9 ± 1 μm). Rising liquid temperature did not result in significantly increased substance loss for citric acid, orange juice and Coca-Cola Zero. Sprite Zero and both fruit teas, however, caused significantly (p < 0.001) more enamel loss at elevated temperature. Not all investigated drinks showed a temperature-induced change in erosivity. For some erosive beverages it can be recommended to keep the consummation temperature as low as possible to decrease the risk of erosive tooth substance loss. Copyright © 2018 Elsevier Ltd. All rights reserved.

Innovative In-Situ Remediation of Contaminated Sediments for Simultaneous Control of Contamination and Erosion. Part 1

DTIC Science & Technology

2010-12-27

Erosion Rates and Critical Shear Stress ......................... 45 Erosion Rate Ratio Analysis...inductively coupled plasma – mass spectrometry Kd – partition coefficient Meq – milliequivalents MNR – monitored natural recovery SRNL-STI-2010...186 Figure 82. Critical Shear Stress Comparison among Biopolymer Materials at 2, 10, and 175 Days. Each value is an average of

The use of spatial empirical models to estimate soil erosion in arid ecosystems.

PubMed

Abdullah, Meshal; Feagin, Rusty; Musawi, Layla

2017-02-01

The central objective of this project was to utilize geographical information systems and remote sensing to compare soil erosion models, including Modified Pacific South-west Inter Agency Committee (MPSIAC), Erosion Potential Method (EPM), and Revised Universal Soil Loss Equation (RUSLE), and to determine their applicability for arid regions such as Kuwait. The northern portion of Umm Nigga, containing both coastal and desert ecosystems, falls within the boundaries of the de-militarized zone (DMZ) adjacent to Iraq and has been fenced off to restrict public access since 1994. Results showed that the MPSIAC and EPM models were similar in spatial distribution of erosion, though the MPSIAC had a more realistic spatial distribution of erosion and presented finer level details. The RUSLE presented unrealistic results. We then predicted the amount of soil loss between coastal and desert areas and fenced and unfenced sites for each model. In the MPSIAC and EPM models, soil loss was different between fenced and unfenced sites at the desert areas, which was higher at the unfenced due to the low vegetation cover. The overall results implied that vegetation cover played an important role in reducing soil erosion and that fencing is much more important in the desert ecosystems to protect against human activities such as overgrazing. We conclude that the MPSIAC model is best for predicting soil erosion for arid regions such as Kuwait. We also recommend the integration of field-based experiments with lab-based spatial analysis and modeling in future research.

Geochemical budget of erosion in the Himalayan system

NASA Astrophysics Data System (ADS)

France-Lanord, C.; Lupker, M.; Lavé, J.

2011-12-01

Geochemistry of detrital sediment allow to constrain present and past processes of erosion and may be used to infer large scale budgets. The sediment flux exported by major rivers, corresponds to net physical erosion of a basin and, if combined with the river's dissolved flux, it allows in principle to quantify total erosion rates as well as the balance between chemical and physical erosion. This is nevertheless depending on our ability to quantify riverine fluxes, sediment composition and average source rock composition. Sediment composition results from weathering, attrition, mixing and sorting processes which determine their properties at a given location and time in the drainage basin. Particle sorting during transport exerts a first order control on bulk sediment composition as well as on trace and isotopic compositions. Repeated sampling of river sediments in the Ganga and Brahmaputra Rivers during the monsoon using depth sampling combined to river velocity profiling (ACDP) show the sensitivity of sediment composition to particle sorting effects that can be linked to hydrodynamic conditions. Applied to the Ganga in Bangladesh, and using a Rousean model, we estimate the average grain size and major element composition (Si, Al, Fe) of sediments exported by the Ganga (Lupker et al. 2011, JGR E.S. in press). This leads to a net sediment flux of ca. 380 million tons/yr which is comparable to fluxes reported from hydrological measurements. The average Al/Si ratio of the sediment is 0.23 which is well bellow values reported for the Upper Continental Crust (UCC≈0.27-0.29) and slightly above estimate of the Himalayan Silicate Crust (HSC) composition deduced from a Central Nepal geological sample collection. Deviations from UCC reflect the recycled nature of Himalayan formations having undergone several orogenic cycles and being enriched in quartz. The similarity with HSC suggest that either (1) there is no segregation due to floodplain sequestration, or (2) that the

Lifespan of mountain ranges scaled by feedbacks between landsliding and erosion by rivers.

PubMed

Egholm, David L; Knudsen, Mads F; Sandiford, Mike

2013-06-27

An important challenge in geomorphology is the reconciliation of the high fluvial incision rates observed in tectonically active mountain ranges with the long-term preservation of significant mountain-range relief in ancient, tectonically inactive orogenic belts. River bedrock erosion and sediment transport are widely recognized to be the principal controls on the lifespan of mountain ranges. But the factors controlling the rate of erosion and the reasons why they seem to vary significantly as a function of tectonic activity remain controversial. Here we use computational simulations to show that the key to understanding variations in the rate of erosion between tectonically active and inactive mountain ranges may relate to a bidirectional coupling between bedrock river incision and landslides. Whereas fluvial incision steepens surrounding hillslopes and increases landslide frequency, landsliding affects fluvial erosion rates in two fundamentally distinct ways. On the one hand, large landslides overwhelm the river transport capacity and cause upstream build up of sediment that protects the river bed from further erosion. On the other hand, in delivering abrasive agents to the streams, landslides help accelerate fluvial erosion. Our models illustrate how this coupling has fundamentally different implications for rates of fluvial incision in active and inactive mountain ranges. The coupling therefore provides a plausible physical explanation for the preservation of significant mountain-range relief in old orogenic belts, up to several hundred million years after tectonic activity has effectively ceased.

Microhardness evaluation of silorane and methacrylate composites submitted to erosion and abrasion processes

PubMed Central

Gazola, Eloá Aguiar; Rego, Marcos Augusto; Brandt, William Cunha; D’Arce, Maria Beatriz Freitas; Liporoni, Priscila Christiane Suzy

2015-01-01

Abstract Objective: The aim of this study was to evaluate the Knoop hardness number (KHN) of methacrylate (MC) and silorane (SC) composites after being submitted to erosion and abrasion processes. Material and methods: Forty samples were made with each composite: MC and SC. The samples were divided into eight groups (n = 10) according to the type of composite (G1–G4, MC; G5–G8, SC) and the beverages involved in the erosion process (G1 and G5 – Control (C), without erosion, with abrasion; G2 and G6 – Orange Juice (OJ), abrasion; G3 and G7 – Smirnoff Ice® (SI), abrasion; G4 and G8 – Gatorade® (GA), abrasion). The KHN test was performed 24 h after the last cycle of erosion/abrasion. Results: The MC groups showed smaller KHN values for the SI group (p < 0.05) when compared to the Control and OJ groups; however, for the SC groups, no differences were found (p > 0.05). Conclusion: Methacrylate composite when submitted to acidic beverages erosive challenge combined with abrasive process might alter its surface microhardness. However, the beverages used in the present study were not able to interfere in silorane composite surface microhardness. PMID:28642903

Exploration of the Esophageal Mucosal Barrier in Non-Erosive Reflux Disease

PubMed Central

Rinsma, Nicolaas F.; Farré, Ricard; Troost, Fred J.; Elizalde, Montserrat; Keszthelyi, Daniel; Helyes, Zsuzsanna; Masclee, Ad A.; Conchillo, José M.

2017-01-01

In the absence of visible mucosal damage, it is hypothesized that the esophageal mucosal barrier is functionally impaired in patients with non-erosive reflux disease (NERD). The aim of the present study was to perform an exploratory analysis of the mucosal barrier in NERD compared to erosive esophagitis (EE) and controls. A second aim was to explore TRPV1 gene transcription in relation to the mucosal barrier function and heartburn symptoms. In this prospective study, 10 NERD patients, 11 patients with active erosive esophagitis and 10 healthy volunteers were included. Biopsies from non-eroded mucosa were obtained for (1) ex vivo analyses (Ussing chamber) of transepithelial electrical resistance (TEER) and permeability (2) gene transcription of tight-junction proteins and transient receptor potential vanilloid subfamily member 1 (TRPV1). No differences in TEER or permeability were found between NERD and healthy volunteers, whereas TEER was lower in patients with erosive esophagitis. TRPV1 gene transcription was not significantly different between EE, NERD and controls. Conclusions: esophageal mucosal barrier function and TRPV1 transcription is not significantly altered in NERD patients. Future research is needed to explore other potential mechanisms that may account for the high symptom burden in these patients. PMID:28534850

Magnetic resonance imaging is more sensitive than radiographs in detecting change in size of erosions in rheumatoid arthritis.

PubMed

Chen, Timothy S; Crues, John V; Ali, Muhammad; Troum, Orrin M

2006-10-01

To evaluate the technological performance of magnetic resonance imaging (MRI) with respect to projection radiography by determining the incidence of changes in the size of individual bone lesions in inflammatory arthritis, using serial high-resolution in-office MRI over short time intervals (8 months average followup), and by comparing the sensitivity of 3-view projection radiography with in-office MRI for detecting changes in size and number of individual erosions. MR examinations of the wrists and second and third metacarpophalangeal joints were performed using a portable in-office MR system in a total of 405 patients with inflammatory arthritis, from one rheumatologist's practice, who were undergoing aggressive disease modifying antirheumatic drug therapy. Of the patients, 156 were imaged at least twice, allowing evaluation of 246 followup examinations (mean followup interval of 8 months over a 2-year period). Baseline and followup plain radiographs were obtained in 165 patient intervals. Patients refused radiographic examination on 81 followup visits. MRI demonstrated no detectable changes in 124 of the 246 (50%) followup MRI examinations. An increase in the size or number of erosions was demonstrated in 74 (30%) examinations, a decrease in the size or number of erosions in 36 (15%), and both increases and decreases in erosions were seen in 11 (4%). In the 165 studies with followup radiographic comparisons, only one examination (0.8%) showed an erosion not seen on the prior examination and one (0.8%) showed an increase in a previously noted erosion. We showed that high-resolution in-office MRI with an average followup of 8 months detects changes in bony disease in 50% of compliant patients during aggressive treatment for inflammatory arthritis in a single rheumatologist's office practice. Plain radiography is insensitive for detecting changes in bone erosions for this patient population in this time frame.

Response of wind erosion dynamics to climate change and human activity in Inner Mongolia, China during 1990 to 2015.

PubMed

Zhang, Haiyan; Fan, Jiangwen; Cao, Wei; Harris, Warwick; Li, Yuzhe; Chi, Wenfeng; Wang, Suizi

2018-10-15

Soil erosion caused by wind is a serious environmental problem that results in land degradation and threatens sustainable development. Accurately evaluating wind erosion dynamics is important for reducing the hazard of wind erosion. Separating the climatic and anthropogenic causes of wind erosion can improve the understanding of its driving mechanisms. Based on meteorological, remote sensing and field observation data, we applied the Revised Wind Erosion Equation (RWEQ) to simulate wind erosion in Inner Mongolia, China from 1990 to 2015. We used the variable control method by input of the average climate conditions to calculate human-induced wind erosion. The difference between natural wind erosion and human-induced wind erosion was determined to assess the effect of climate change on wind erosion. The results showed that the wind erosion modulus had a remarkable decline with a slope of 52.23 t/km 2 /a from 1990 to 2015. During 26 years, the average wind erosion for Inner Mongolia amounted to 63.32 billion tons. Wind erosion showed an overall significant decline of 49.23% and the partial severer erosion hazard significantly increased by 7.11%. Of the significant regional decline, 40.72% was caused by climate changes, and 8.51% was attributed to ecological restoration programs. For the significant regional increases of wind erosion, 4.29% was attributed to climate changes and 2.82% to human activities, mainly overgrazing and land use/cover changes. During the study, the driving forces in Inner Mongolia of wind erosion dynamics differed spatially. Timely monitoring based on multi-source data and highlighting the importance of positive human activities by increasing vegetation coverage for deserts, reducing grazing pressure on grasslands, establishing forests as windbreaks and optimizing crop planting rotations of farmlands can all act to reduce and control wind erosion. Copyright © 2018 Elsevier B.V. All rights reserved.

Supporting the Future Air Traffic Control Projection Process

NASA Technical Reports Server (NTRS)

Davison, Hayley J.; Hansman, R. John, Jr.

2002-01-01

In air traffic control, projecting what the air traffic situation will be over the next 30 seconds to 30 minutes is a key process in identifying conflicts that may arise so that evasive action can be taken upon discovery of these conflicts. A series of field visits in the Boston and New York terminal radar approach control (TRACON) facilities and in the oceanic air traffic control facilities in New York and Reykjavik, Iceland were conducted to investigate the projection process in two different ATC domains. The results from the site visits suggest that two types of projection are currently used in ATC tasks, depending on the type of separation minima and/or traffic restriction and information display used by the controller. As technologies improve and procedures change, care should be taken by designers to support projection through displays, automation, and procedures. It is critical to prevent time/space mismatches between interfaces and restrictions. Existing structure in traffic dynamics could be utilized to provide controllers with useful behavioral models on which to build projections. Subtle structure that the controllers are unable to internalize could be incorporated into an ATC projection aid.

Soil erosion in Iran: Issues and solutions

NASA Astrophysics Data System (ADS)

Hamidreza Sadeghi, Seyed; Cerdà, Artemi

2015-04-01

Iran currently faces many soil erosion-related problems (see citations below). These issues are resulted from some inherent characteristic and anthropogenic triggering forces. Nowadays, the latter plays more important rule to accelerate the erosion with further emphasis on soil erosion-prone arid and semi arid regions of the country. This contribution attempts to identify and describe the existing main reasons behind accelerated soil erosion in Iran. Appropriate solutions viz. structural and non-structural approaches will be then advised to combat or minimise the problems. Iran can be used as a pilot research site to understand the soil erosion processes in semiarid, arid and mountainous terrain and our research will review the scientific literature and will give an insight of the soil erosion rates in the main factors of the soil erosion in Iran. Key words: Anthropogenic Erosion, Land Degradation; Sediment Management; Sediment Problems Acknowledgements The research projects GL2008-02879/BTE, LEDDRA 243857 and PREVENTING AND REMEDIATING DEGRADATION OF SOILS IN EUROPE THROUGH LAND CARE (RECARE)FP7-ENV-2013- supported this research. References Aghili Nategh, N., Hemmat, A., & Sadeghi, M. (2014). Assessing confined and semi-confined compression curves of highly calcareous remolded soil amended with farmyard manure. Journal of Terramechanics, 53, 75-82. Arekhi, S., Bolourani, A. D., Shabani, A., Fathizad, H., Ahamdy-Asbchin, S. 2012. Mapping Soil Erosion and Sediment Yield Susceptibility using RUSLE, Remote Sensing and GIS (Case study: Cham Gardalan Watershed, Iran). Advances in Environmental Biology, 6(1), 109-124. Arekhi, S., Shabani, A., Rostamizad, G. 2012. Application of the modified universal soil loss equation (MUSLE) in prediction of sediment yield (Case study: Kengir Watershed, Iran). Arabian Journal of Geosciences, 5(6), 1259-1267.Sadeghi, S. H., Moosavi, V., Karami, A., Behnia, N. 2012. Soil erosion assessment and prioritization of affecting factors at plot

Erosion protection for soil slopes along Virginia's highways.

DOT National Transportation Integrated Search

2000-01-01

A survey of the state of practice for designing slope erosion control measures within VDOT's nine districts has been conducted. On the basis of the survey, it is clear that there are no specific design procedures currently in use within VDOT for deal...

Erosion Risks in Selected Watersheds for the 2005 School Fire Located Near Pomeroy, Washington on Predominately Ash-Cap Soils

Treesearch

William Elliot; Ina Sue Miller; Brandon Glaza

2007-01-01

A limited erosion potential analysis was carried out on the 50,000 acre School Fire. Three WEPP interfaces were used for the analysis, a GIS wizard, an online interface and a windows interface. Ten watersheds within the fire area were modeled with the GeoWEPP tool (a geo-spatial interface for WEPP, Water Erosion Predication Project). The watersheds covered 18,823 acres...

Tooth erosion and eating disorders: a systematic review and meta-analysis.

PubMed

Hermont, Ana Paula; Oliveira, Patrícia A D; Martins, Carolina C; Paiva, Saul M; Pordeus, Isabela A; Auad, Sheyla M

2014-01-01

Eating disorders are associated with the highest rates of morbidity and mortality of any mental disorders among adolescents. The failure to recognize their early signs can compromise a patient's recovery and long-term prognosis. Tooth erosion has been reported as an oral manifestation that might help in the early detection of eating disorders. The aim of this systematic review and meta-analysis was to search for scientific evidence regarding the following clinical question: Do eating disorders increase the risk of tooth erosion? An electronic search addressing eating disorders and tooth erosion was conducted in eight databases. Two independent reviewers selected studies, abstracted information and assessed its quality. Data were abstracted for meta-analysis comparing tooth erosion in control patients (without eating disorders) vs. patients with eating disorders; and patients with eating disorder risk behavior vs. patients without such risk behavior. Combined odds ratios (ORs) and a 95% confidence interval (CI) were obtained. Twenty-three papers were included in the qualitative synthesis and assessed by a modified version of the Newcastle-Ottawa Scale. Fourteen papers were included in the meta-analysis. Patients with eating disorders had more risk of tooth erosion (OR = 12.4, 95%CI = 4.1-37.5). Patients with eating disorders who self-induced vomiting had more risk of tooth erosion than those patients who did not self-induce vomiting (OR = 19.6, 95%CI = 5.6-68.8). Patients with risk behavior of eating disorder had more risk of tooth erosion than patients without such risk behavior (Summary OR = 11.6, 95%CI = 3.2-41.7). The scientific evidence suggests a causal relationship between tooth erosion and eating disorders and purging practices. Nevertheless, there is a lack of scientific evidence to fulfill the basic criteria of causation between the risk behavior for eating disorders and tooth erosion.

Spatial and temporal variations of wind erosion climatic erosivity in the farming-pastoral zone of Northern China

NASA Astrophysics Data System (ADS)

Yue, Shuping; Yang, Ruixin; Yan, Yechao; Yang, Zhengwei; Wang, Dandan

2018-03-01

Wind erosion climatic erosivity is an important parameter to assess the possible effects of climatic conditions on wind erosion. In this paper, the wind erosion climatic factor (C-factor), which was used to quantify the wind erosion climatic erosivity, was calculated for the period 1960-2014 based on monthly meteorological data collected from 101 stations in the farming-pastoral zone of Northern China. The Mann-Kendall (M-K) test, trend analysis, and geostatistical analysis methods were used to explore the spatial and temporal characteristics of the wind erosion climatic erosivity in this region. The result suggests that the annual C-factor, with a maximum of 76.05 in 1969 and a minimum of 26.57 in 2007, has a significant decreasing trend over the past 55 years. Strong seasonality in the C-factor was found, with the highest value in spring, which accounts for a significant proportion of the annual C-factor (41.46%). However, the coefficient of variation of the seasonal C-factor reaches a maximum in winter and a minimum in spring. The mean annual C-factor varies substantially across the region. Areas with high values of the mean annual C-factor (C ≥ 100) are located in Ulanqab and Dingxi, while areas with low values (C ≤ 10) lie in Lanzhou, Linxia, Dingxi, Xining, and Chengde. Spatial analysis on the trend of the C-factor reveals that 81% of the stations show statistically significant decreases at a 90% confidence level. An examination of the concentration ratio of the C-factor shows that the wind erosion climatic erosivity is concentrated in spring, especially in April, which makes this period particularly important for implementing soil conservation measures.

Finding balance between fire hazard reduction and erosion control in the Lake Tahoe Basin, California–Nevada

Treesearch

Nicolas M. Harrison; Andrew P. Stubblefield; J. Morgan Varner; Eric E. Knapp

2016-01-01

The 2007 Angora Fire served as a stark reminder of the need for fuel reduction treatments in the Lake Tahoe Basin, California–Nevada, USA. Concerns exist, however, that the corresponding removal of forest floor fuels could increase erosion rates, negatively affecting the clarity of Lake Tahoe. To quantify trade-offs between fuel reduction and erosion, we conducted...

Solid particle erosion mechanisms of protective coatings for aerospace applications

NASA Astrophysics Data System (ADS)

Bousser, Etienne

The main objective of this PhD project is to investigate the material loss mechanisms during Solid Particle Erosion (SPE) of hard protective coatings, including nanocomposite and nanostructured systems. In addition, because of the complex nature of SPE mechanisms, rigorous testing methodologies need to be employed and the effects of all testing parameters need to be fully understood. In this PhD project, the importance of testing methodology is addressed throughout in order to effectively study the SPE mechanisms of brittle materials and coatings. In the initial stage of this thesis, we studied the effect of the addition of silicon (Si) on the microstructure, mechanical properties and, more specifically, on the SPE resistance of thick CrN-based coatings. It was found that the addition of Si significantly improved the erosion resistance and that SPE correlated with the microhardness values, i.e. the coating with the highest microhardness also had the lowest erosion rate (ER). In fact, the ERs showed a much higher dependence on the surface hardness than what has been proposed for brittle erosion mechanisms. In the first article, we study the effects of the particle properties on the SPE behavior of six brittle bulk materials using glass and alumina powders. First, we apply a robust methodology to accurately characterize the elasto-plastic and fracture properties of the studied materials. We then correlate the measured ER to materials' parameters with the help of a morphological study and an analysis of the quasi-static elasto-plastic erosion models. Finally, in order to understand the effects of impact on the particles themselves and to support the energy dissipation-based model proposed here, we study the particle size distributions of the powders before and after erosion testing. It is shown that tests using both powders lead to a material loss mechanism related to lateral fracture, that the higher than predicted velocity exponents point towards a velocity

Assessment and management of dental erosion.

PubMed

Wang, Xiaojie; Lussi, Adrian

2010-07-01

Studies have shown a growing trend toward increasing prevalence of dental erosion, associated with the declining prevalence of caries disease in industrialized countries. Erosion is an irreversible chemical process that results in tooth substance loss and leaves teeth susceptible to damage as a result of wear over the course of an individual's lifetime. Therefore, early diagnosis and adequate prevention are essential to minimize the risk of tooth erosion. Clinical appearance is the most important sign to be used to diagnose erosion. The Basic Erosive Wear Examination (BEWE) is a simple method to fulfill this task. The determination of a variety of risk and protective factors (patient-dependent and nutrition-dependent factors) as well as their interplay are necessary to initiate preventive measures tailored to the individual. When tooth loss caused by erosive wear reaches a certain level, oral rehabilitation becomes necessary. Copyright 2010 Elsevier Inc. All rights reserved.

Soil erosion and sediment production on watershed landscapes: Processes and control

Treesearch

Peter F. Ffolliott; Kenneth N. Brooks; Daniel G. Neary; Roberto Pizarro Tapia; Pablo Garcia-Chevesich

2013-01-01

Losses of the soil resources from otherwise productive and well functioning watersheds is often a recurring problem confronting hydrologists and watershed managers. These losses of soil have both on-site and off-site effects on the watershed impacted. In addition to the loss of inherent soil resources through erosion processes, on-site effects can include the breakdown...

Medication-related dental erosion: a review.

PubMed

Thomas, Manuel S; Vivekananda Pai, A R; Yadav, Amit

2015-10-01

Dental erosion has become a major problem that affects the long-term health of the dentition. Among the various potential causes for erosive tooth wear, the different drugs prescribed for patients may be overlooked. Several therapeutic medications can directly or indirectly be associated with dental erosion. It is the responsibility of oral health providers to make both patients and colleagues aware of drugs that may contribute to this condition. Therefore, the purpose of this discussion is to provide an overview of the various therapeutic medications that can be related to tooth erosion. The authors also include precautionary measures-summarized as The 9 Rs-to avoid or at least reduce medication-induced erosion.

INNOVATIVE IN-SITU REMEDIATION OF CONTAMINATED SEDIMENTS FOR SIMULTANEOUS CONTROL OF CONTAMINATION AND EROSION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knox, A; Michael Paller, M; Danny D. Reible, D

2007-11-28

New technologies are needed that neutralize contaminant toxicity and control physical transport mechanisms that mobilize sediment contaminants. The last 12 months of this comprehensive project investigated the use of combinations of sequestering agents to develop in situ active sediment caps that stabilize mixtures of contaminants and act as a barrier to mechanical disturbance under a broad range of environmental conditions. Efforts focused on the selection of effective sequestering agents for use in active caps, the composition of active caps, and the effects of active cap components on contaminant bioavailability and retention. Results from this project showed that phosphate amendments, somemore » organoclays, and the biopolymer, chitosan, were very effective at removing metals from both fresh and salt water. These amendments also exhibited high retention (80% or more) of most metals indicating reduced potential for remobilization to the water column. Experiments on metal speciation and retention in contaminated sediment showed that apatite and organoclay can immobilize a broad range of metals under both reduced and oxidized conditions. These studies were followed by sequential extractions to evaluate the bioavailability and retention of metals in treated sediments. Metal fractions recovered in early extraction steps are more likely to be bioavailable and were termed the Potentially Mobile Fraction (PMF). Less bioavailable fractions collected in later extraction steps were termed the Recalcitrant Factor (RF). Apatite and organoclay reduced the PMF and increased the RF for several elements, especially Pb, Zn, Ni, Cr, and Cd. Empirically determined partitioning coefficients and modeling studies were used to assess the retention of organic contaminants on selected sequestering agents. Organoclays exhibited exceptionally high sorption of polycyclic aromatic hydrocarbons as indicated by a comparison of K{sub d} values among 12 amendments. These results suggested

Report on: Connecticut River Streambank Erosion Study, Massachusetts, New Hampshire and Vermont

DTIC Science & Technology

1979-11-01

Plastic filter cloths are used with considerable success beneath tiprap and other revetment materials such as articulated concrete blocks . The...rihutior unlimited II. SUPPLEMENTARY NOTES It. KEY WORDS (Continue on fever&e elde ifneceeeery and identify by block number). alluvial channel...erosion boat waves shear stress rock riprap lower bank erosion revetments flow control vegetation 20. ABSTRACT (Continue on reverse aide if neceesary and