How Efficient is Vegetation in Reducing Wind Erosion and Emission of Health-Threatening Fine Dust PM10? - A Wind Tunnel Approach

NASA Astrophysics Data System (ADS)

Burri, K.; Graf, F.

2009-04-01

World wide, wind erosion and desertification are most alarming processes of environmental degradation. Not only do they cause tremendous losses of fertile soil, but they also seriously affect human health. Pulmonary tuberculosis (silicosis) is one of the major diseases that have been linked to mineral fine dust (PM10) in the atmosphere. It is widely accepted that the re-establishment of an intact vegetation cover is the most effective measure against wind erosion. However, despite numerous investigations, the mechanisms responsible for the protective effect of vegetation are still not completely understood. Since the phenomenon involves highly variable interactions between soil, plants and atmosphere, it is particularly difficult to quantify the efficiency of vegetation in reducing wind erosion. As an alternative to field investigations, wind tunnel experiments offer the advantage to control specific parameters within this highly complex system. In this study, a series of wind tunnel experiments was performed including measurements of sediment transport and PM10 emission in differently dense grass canopies of Lolium perenne (91, 24, 5 and 0 plants per square meter). The novelty of the present wind tunnel study is the use of living plants instead of artificial imitations or dead plant parts. Although more and more sophisticated imitations of vegetation have been used in recent studies, the behaviour of living plants is likely to differ significantly. Coloured quartz sand was used for visualizing sand erosion and deposition patterns. The vertical profiles of aeolian sediment flux were analysed with a stackable sediment sampler composed of 60 collecting boxes, each with a height of 1 cm. The results of this study confirm that both sediment transport and PM10 emission strongly decrease with increasing plant cover. The protective effect of the plants was found to be linked to characteristic changes in the vertical profile of aeolian sediment flux and to specific spatial patterns of sediment deposition. Furthermore, observations indicate that the performance of plants in wind erosion control strongly depends on plant species specific characteristics, particularly growth form and stiffness, as well as on their physiological state. The use of living plants in wind tunnel experiments offers the possibility to study a wide range of more specific aspects of biological wind erosion control. As a next step it is planned to test the effect of mycorrhizal fungi on the wind erodibility of vegetated soil systems.

Dust-associated Microbiomes from Dryland Wheat Fields Differ with Tillage Practice and Biosolids Application

USDA-ARS?s Scientific Manuscript database

Wind erosion is a significant threat to the productivity and sustainability of agricultural soils. In the dryland winter wheat (Triticum aestivum L.)-fallow region of Inland Pacific Northwest of the USA (PNW), farmers increasingly use conservation tillage practices to control wind erosion. In addit...

[Impact of wind-water alternate erosion on the characteristics of sediment particles].

PubMed

Tuo, Deng-Feng; Xu, Ming-Xiang; Ma, Xin-Xin; Zheng, Shi-Qing

2014-02-01

Wind and water are the two dominant erosion agents that caused soil and water losses in the wind-water alternate erosion region on the Loess Plateau. It is meaningful to study the impact of wind-water alternate erosion on the characteristics of soil particles for understanding the response of soil quality and environment to erosion. Through wind tunnel combined rainfall simulation, this paper studied the characteristics of the erosive sediment particles under the effect of wind-water alternate erosion. The results showed that the particles of 0-1 cm soil were coarsened by wind erosion at the wind speeds of 11 and 14 m x s(-1) compared with no wind erosion. Soil fine particles (< 0.01 mm) decreased by 9.8%-10.8%, and coarse particles (> 0.05 mm) increased by 16.8%-20.8%. The physical property of surface soil was changed by the wind erosion, which, in turn, caused an increase in finer particles content in the sediment. Compared with no wind erosion, fine particles (< 0.01 mm) in sediment under the water-wind alternate erosion increased by 2.7%-18.9% , and coarse particles (> 0.05 mm) decreased by 3.7%-9.3%. However, the changing trend of erosive sediment particles after the wind erosion at wind speeds of 11 and 14 m x s(-1) was different along with the rainfall intensity and duration. The erosive sediment particles at the rainfall intensities of 60, 80, 100 mm x h(-1) changed to greater extents than at the 150 mm x h(-1) rainfall intensity with longer than 15 min runoff flowing.

Statistical characterization of wind-wave induced sediment resuspension events in shallow tidal basins

NASA Astrophysics Data System (ADS)

D'Alpaos, A.; Carniello, L.; Rinaldo, A.

2013-12-01

Wind-wave induced erosion processes play a critical role on the morphodynamic evolution of shallow tidal landscapes. Both in the horizontal and in the vertical planes, patterns of wind-induced bottom shear stresses contribute to control the morphological and biological features of the tidal landscape, through the erosion of tidal-flat surfaces and of salt-marsh margins, the disruption of the polymeric microphytobenthic biofilm, and the increase in suspended sediment concentration which affects the stability of intertidal ecosystems. Towards the goal of developing a synthetic theoretical framework to represent wind wave-induced resuspension events and account for their erosional effects on the long-term biomorphodynamic evolution of tidal systems, we have employed a complete, coupled finite element model accounting for the role of wind waves and tidal currents on the hydrodynamic circulation in shallow basins. Our analysis of the characteristics of combined current and wave-induced exceedances in bottom shear stress over a given threshold for erosion, suggest that wind wave-induced resuspension events can be modeled as a marked Poisson process. Moreover, the analysis of wind-wave induced resuspension events for different historical configurations of the Venice Lagoon shows that the interarrival times of erosion events have decreased through the last two centuries, whereas the intensities of erosion events have increased. This allows us to characterize the threatening erosion and degradation processes that the Venice Lagoon has been experiencing since the beginning of the last century.

Simulations of wind erosion along the Qinghai-Tibet Railway in north-central Tibet

NASA Astrophysics Data System (ADS)

Jiang, Yingsha; Gao, Yanhong; Dong, Zhibao; Liu, Benli; Zhao, Lin

2018-06-01

Wind erosion along the Qinghai-Tibet Railway causes sand hazard and poses threats to the safety of trains and passengers. A coupled land-surface erosion model (Noah-MPWE) was developed to simulate the wind erosion along the railway. Comparison with the data from the 137Cs isotope analysis shows that this coupled model could simulate the mean erosion amount reasonably. The coupled model was then applied to eight sites along the railway to investigate the wind-erosion distribution and variations from 1979 to 2012. Factors affecting wind erosion spatially and temporally were assessed as well. Majority wind erosion occurs in the non-monsoon season from December to April of the next year except for the site located in desert. The region between Wudaoliang and Tanggula has higher wind erosion occurrences and soil lose amount because of higher frequency of strong wind and relatively lower soil moisture than other sites. Inter-annually, all sites present a significant decreasing trend of annual soil loss with an average rate of -0.18 kg m-2 a-1 in 1979-2012. Decreased frequency of strong wind, increased precipitation and soil moisture contribute to the reduction of wind erosion in 1979-2012. Snow cover duration and vegetation coverage also have great impact on the occurrence of wind erosion.

Wind erosion of soils burned by wildfire

Treesearch

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

2011-01-01

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

Validation of SWEEP for contrasting agricultural land use types in the Tarim Basin

USDA-ARS?s Scientific Manuscript database

In order to aid in identifying land management practices with the potential to control soil erosion, models such as the Wind Erosion Prediction System (WEPS) have been developed to assess soil erosion. The objective of this study was to test the performance of the WEPS erosion submodel (the Single-e...

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...

Post-fire soil nutrient redistribution in northern Chihuahuan Desert

NASA Astrophysics Data System (ADS)

Wang, G.; Li, J. J.; Ravi, S.; Sankey, J. B.; Duke, D.; Gonzales, H. B.; Van Pelt, S.

2016-12-01

The desert grassland in the southwestern US has undergone dramatic land degradation with woody shrub encroachment over the last 150 years. Wind erosion and periodic fires are major drivers of vegetation dynamics in these ecosystems. Due to climate change and anthropogenic disturbances, many drylands are undergoing changes in fire regimes, which can largely alter the nutrient loss rate as well as the soil resource heterogeneity. In this study, we used manipulative field experiments, laboratory and geostatistical analyses to investigate the distribution of fertile islands, nutrient loss rate and spatial variation. Replicated burned and control experimental plots were set up in a desert grassland in northern Chihuahuan Desert in March 2016. Windblown sediments were monitored by multiple MWAC sediment collectors on each plot. Surface soil samples, with their locations accurately recorded (i.e., under shrub, under grass, and bare interspace) were collected twice per year in spring and again in summer after the experimental setup. Our preliminary results show that the spatial heterogeneity of soil C and N in the burned plots has changed notably compared to the control plots. Our results further demonstrated that areas with burned shrubs is most vulnerable to wind erosion, therefore the soil nutrient loss is most significant, almost five times of the nutrient loss rate of bare areas. Interspace bare areas is in the lowest micro-land and some of the surface has caliche, which makes the surface resistant to wind erosion. And areas with burned grass receive the lightest wind erosion and nutrient loss, around one third of the erosion on bare areas, because burned grasses still cover the surface and the dead bodies can eliminate wind erosion to a large extent. Hence, periodic fire in desert grassland favors the evenness distribution of soil nutrients and can retard the shrub encroachment process.

Evaluation of the RWEQ and SWEEP in simulating soil and PM10 loss from a portable wind tunnel

USDA-ARS?s Scientific Manuscript database

Wind erosion threatens sustainable agriculture and environmental quality in the Columbia Plateau region of the US Pacific Northwest. Wind erosion models such as Wind Erosion Prediction System (WEPS) and the Revised Wind Erosion Equation (RWEQ) have been developed as tools for identifying practices t...

Wind erosion in the alpine zone - a case study at Latschuelfurgga (Davos, Switzerland)

NASA Astrophysics Data System (ADS)

Graf, F.; Gromke, Ch.

2012-04-01

Protection against wind erosive processes ranks among the most important challenges in natural hazard mitigation, worldwide. Today, it is generally accepted that the (re-)establishment of a protective vegetation cover is the most promising and efficient measure in restoring degraded land in the long term. Sustainable protection against wind erosion requires adequate information about suitable plant species regarding ecological aspects as well as with respect to their proper contribution to wind erosion control. The latter, however, is widely lacking. Within a broader conceptual framework, wind tunnel studies have been performed using naturally grown vegetation covers. The use of live plants aimed at simulating the behaviour of natural canopies as accurately as possible compared to previous studies using artificial objects. The goals of the presented field study are to record reliable data on windblown erosion rates under natural alpine conditions on the one hand and, on the other hand, to interrelate the findings with the results of the wind tunnel experiments with live plants. The wind erosion test field was established at 2409 m a.s.l. on a small saddle like pass in an alpine meadow and includes two east-west orientated test tracks of the dimension 2x10 m2. One track is left as is, representing the naturally alpine vegetated soil (15-20% plant cover). The other track is equipped with a plastic covering sheet, mimicking desertified soil (0% plant cover) and serving as control plot as well as providing a direct link to the wind tunnel experiments. Blue and red quartz sand (grain size: 0.2-0.6 mm) was spread on the vegetated and sheet-covered track, respectively, to visualise and measure the effect of vegetation on wind erosion control. During summer and fall 2010 field experiments were performed of which experiment no. 4 is presented here as a case study as well as compared with and discussed in relation to a wind tunnel run with medium-density configuration (16% plant cover). The measuring equipment consists of three climate stations recording wind direction and wind speed at 50, 100, and 200 cm, air temperature and humidity, incoming and reflected short- and long wave radiation, as well as precipitation. Leeward of the two test tracks, panels and ground-plates were installed equipped with sticky foils to trap and quantify vertical and horizontal particle transport. Compared to the desertified soil (0% plant cover) it was found that only small amounts of sand from the vegetated plot (15-20% plant cover) were transported, even during heavy wind events. Overall the ratio varied from 1:50 to 1:175 depending on the position of the panels and ground plates. Qualitatively similar findings, however quantitatively less pronounced, resulted from the wind tunnel experiments (ratio = 1:15). The difference between the field study and the wind tunnel results is quite remarkable and implies that the sheltering effect of vegetation under natural conditions is 3 to 12 times higher than found for the medium-density experiment in the wind tunnel (16% plant cover). However, this conclusion needs careful reflection. After all, the two studies differ in several aspects of their set-up. Correspondingly, the data are speculatively discussed, particularly with respect to meteorological parameters (wind speed, turbulence intensity, humidity, temperature), ecological aspects, and hydrological processes.

Biophysical response of dryland soils to rainfall: implications for wind erosion

NASA Astrophysics Data System (ADS)

Bullard, J. E.; Strong, C. L.; Aubault, H.

2016-12-01

Dryland soils can be highly susceptible to wind erosion due to low vegetation cover. The formation of physical and biological soil crusts between vascular plants can exert some control on the soil surface erodibility. The development of these crusts is highly dependent on rainfall which causes sediment compaction and aggregate breakdown, and triggers photosynthetic activity and an increase soil organic matter within biological soil crusts. Using controlled field experiments, this study tests how biological soil crusts in different dryland geomorphic settings respond to various rainfall amounts (0, 5 or 10 mm) and how this in turn affects the resistance of soils to wind erosion. Results show that 10 mm of rainfall triggers more intense photosynthetic activity (high fluorescence) and a greater increase in extracellular polysaccharide content in biological crusts than 5 mm of rainfall but that the duration of photosynthetic activity is comparable for both quantities of rain. These biological responses have little impact on surface resistance, but results show that soils are more susceptible to wind erosion after rainfall events than in their initial dry state. This unexpected result could be explained by the detachment of surface sediments by raindrop impact and overland flow. The study highlights the complexity of soil erodibility at small scale which is driven by rain, wind and crust, and a necessity to understand how the spatial heterogeneity of crust and their ecophysiology alters small scale processes.

[Ecological benefits of planting winter rapeseed in western China].

PubMed

Wang, Xue-fang; Sun, Wan-cang; Li, Fang; Kang, Yan-li; Pu, Yuan-yuan; Liu, Hong-xia; Zeng, Chao-wu; Fan, Chong-xiu

2009-03-01

To evaluate the ecological benefits of popularizing winter rapeseed planting in western China, a wind tunnel simulation test was conducted with four kinds of farmland surface, i.e., winter rapeseed, winter wheat, wheat stubble, and bare field just after spring sowing, collected from west Gansu in April. The results showed that winter rapeseed surface had a roughness of 4.08 cm and a threshold wind velocity as high as 14 m x s(-1), being more effective in blown sand control than the other three surfaces. Under the same experimental conditions, the wind erosion modulus and sand transportation rate of winter rapeseed surface were only 4.1% and 485% of those of the bare field just after spring sowing, and the losses of soil organic matter, alkali-hydrolyzed N, available P and K, catalase, urease, alkaline phosphatase, invertase, and microbes of winter rapeseed surface due to wind erosion were only 1.4%, 5.1%, 1.6%, 2.7%, 9.7%, 3.6%, 6.3%, 6.7% and 1.5% of those of the bare field, respectively. It was suggested that popularizing winter rapeseed planting in west China could control wind erosion, retain soil water and nutrients, increase multicropping index, and improve economic benefits of farmland. In addition, it could benefit the regional desertification control and ecological environment improvement.

Particle transport patterns of short-distance soil erosion by wind-driven rain, rain and wind

NASA Astrophysics Data System (ADS)

Marzen, Miriam; Iserloh, Thomas; de Lima, João L. M. P.; Ries, Johannes B.

2015-04-01

Short distance erosion of soil surface material is one of the big question marks in soil erosion studies. The exact measurement of short-distance transported soil particles, prior to the occurrence of overland flow, is a challenge to soil erosion science due to the particular requirements of the experimental setup and test procedure. To approach a quantification of amount and distance of each type of transport, we applied an especially developed multiple-gutter system installed inside the Trier Portable Wind and Rainfall Simulator (PWRS). We measured the amount and travel distance of soil particles detached and transported by raindrops (splash), wind-driven rain (splash-saltation and splash-drift) and wind (saltation). The test setup included three different erosion agents (rain/ wind-driven rain/ wind), two substrates (sandy/ loamy), three surface structures (grain roughness/ rills lengthwise/ rills transversal) and three slope angles (0°/+7°/-7°). The results present detailed transport patterns of the three erosion agents under the varying soil and surface conditions up to a distance of 1.6 m. Under the applied rain intensity and wind velocity, wind-driven rain splash generates the highest erosion. The erodibility and travel distance of the two substrates depend on the erosion agent. The total erosion is slightly higher for the slope angle -7° (downslope), but for wind-driven rain splash, the inclination is not a relevant factor. The effect of surface structures (rills) changes with traveling distance. The wind driven rain splash generates a much higher amount of erosion and a further travel distance of the particles due to the combined action of wind and rain. The wind-driven rain factor appears to be much more significant than the other factors. The study highlights the effects of different erosion agents and surface parameters on short-distance particle transport and the powerful impact of wind-driven rain on soil erosion.

AERO: A Decision Support Tool for Wind Erosion Assessment in Rangelands and Croplands

NASA Astrophysics Data System (ADS)

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

2015-12-01

Wind erosion is a key driver of global land degradation, with on- and off-site impacts on agricultural production, air quality, ecosystem services and climate. Measuring rates of wind erosion and dust emission across land use and land cover types is important for quantifying the impacts and identifying and testing practical management options. This process can be assisted by the application of predictive models, which can be a powerful tool for land management agencies. The Aeolian EROsion (AERO) model, a wind erosion and dust emission model interface provides access by non-expert land managers to a sophisticated wind erosion decision-support tool. AERO incorporates land surface processes and sediment transport equations from existing wind erosion models and was designed for application with available national long-term monitoring datasets (e.g. USDI BLM Assessment, Inventory and Monitoring, USDA NRCS Natural Resources Inventory) and monitoring protocols. Ongoing AERO model calibration and validation are supported by geographically diverse data on wind erosion rates and land surface conditions collected by the new National Wind Erosion Research Network. Here we present the new AERO interface, describe parameterization of the underpinning wind erosion model, and provide a summary of the model applications across agricultural lands and rangelands in the United States.

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.…

Scaling up from field to region for wind erosion prediction using a field-scale wind erosion model and GIS

USGS Publications Warehouse

Zobeck, T.M.; Parker, N.C.; Haskell, S.; Guoding, K.

2000-01-01

Factors that affect wind erosion such as surface vegetative and other cover, soil properties and surface roughness usually change spatially and temporally at the field-scale to produce important field-scale variations in wind erosion. Accurate estimation of wind erosion when scaling up from fields to regions, while maintaining meaningful field-scale process details, remains a challenge. The objectives of this study were to evaluate the feasibility of using a field-scale wind erosion model with a geographic information system (GIS) to scale up to regional levels and to quantify the differences in wind erosion estimates produced by different scales of soil mapping used as a data layer in the model. A GIS was used in combination with the revised wind erosion equation (RWEQ), a field-scale wind erosion model, to estimate wind erosion for two 50 km2 areas. Landsat Thematic Mapper satellite imagery from 1993 with 30 m resolution was used as a base map. The GIS database layers included land use, soils, and other features such as roads. The major land use was agricultural fields. Data on 1993 crop management for selected fields of each crop type were collected from local government agency offices and used to 'train' the computer to classify land areas by crop and type of irrigation (agroecosystem) using commercially available software. The land area of the agricultural land uses was overestimated by 6.5% in one region (Lubbock County, TX, USA) and underestimated by about 21% in an adjacent region (Terry County, TX, USA). The total estimated wind erosion potential for Terry County was about four times that estimated for adjacent Lubbock County. The difference in potential erosion among the counties was attributed to regional differences in surface soil texture. In a comparison of different soil map scales in Terry County, the generalised soil map had over 20% more of the land area and over 15% greater erosion potential in loamy sand soils than did the detailed soil map. As a result, the wind erosion potential determined using the generalised soil map Was about 26% greater than the erosion potential estimated by using the detailed soil map in Terry County. This study demonstrates the feasibility of scaling up from fields to regions to estimate wind erosion potential by coupling a field-scale wind erosion model with GIS and identifies possible sources of error with this approach.

Wind, rain and soil erosion rates on bare and plant covered agriculture plots at the experimental station of El Teularet -Sierra de Enguera, Eastern Spain

NASA Astrophysics Data System (ADS)

Cerdà, A.; Azorin-Molina, C.; Iserloh, Th.

2012-04-01

Soil erosion is being scientifically researched for more tan one century, but there is some knowledge lacks that should be researched. Within the factors of the soil erosion wind and rain were studied, but little is know about the impact of the combination of both. Soil erosion by wind was mainly studied on drylands and agriculture land (Sterk and Spaan, 1997; Bielders et al., 2002; Rajot et al., 2003; Zobeck et al., 2003). Soil erosion by water was studied in many ecosystems but it is especially active on agriculture land (Cerdà et al., 2009) and under Mediterranean climatic conditions (Cerdà et al., 2010). The importance of wind on soil erosion is base in the fact that rainstorms occurs with wind, adding a driving component to the falling raindrops. The influence of wind on raindrops is clear, but there is not measurements and there is no information of this influence under field conditions with natural rainfall events.This paper aims to determine the interaction between wind and rain as factors of the soil losses under Mediterranean climatic conditions and different agriculture managements and land uses. Since 2003, the El Teularet-Serra de Enguera Soil Erosion Experimental Station located in Eastern Spain is measuring the soil losses in plots under different land uses and land managements. The station is devoted to study the soil water erosion processes under rain-fed agriculture fields and the rangelands by means of simulated rainfall experiments and plots of different sizes. The soil erosion measure ments are done by means of 13 plots, each of them composed of 5 subplots of 1, 2, 4, 16 and 48 m2 under different land uses and managements. Two plots are covered by two different types of shrubs: Quercus coccifera and Ulex parviflorus, respectively. Three plots reproduce the use of herbicides, one is ploughed, and three plots follow conservation practices (oats and beans with no-tillage, with tillage, and with a vege- tation cover of weeds). Other plots are covered with straw, chipped branches of olive and with a geotextil developed specifically to control erosion on agricultural fields. The Soil Erosion Experimental Station of the El Teularet-Serra de Enguera is located in Eastern Spain. The station is devoted to study the soil water erosion processes under rain-fed agriculture fields and the rangelands. Agriculture is the main source of sedi ments on the mountainous areas of Spain due to the current management. The exper imental station of the El Teularet-Sierra de Enguera is composed also of a meteorological station with tipping-bucket raingauges (0.2 mm), and sensors that measure soil and air moisture and temperature, wind direction and speed and the sun radiation connected to a data-logger that record these data every five minutes. This paper will review the data collected during the period 2004 to 2011 in order to determine if the wind direction and wind speed determined the soil erosion rates. In this way it will be clarified the infliuence of wind on the soil erosion processes.The results will be compared to the measurement collected at the Montesa experimental station devoted to the study of soil erosion on citrus orchards. The experimental setup within the citrus plantation is being supported by the research project CGL2008- 02879/BTE.

Relative contributions of wind and water erosion to total soil loss and its effect on soil properties in sloping croplands of the Chinese Loess Plateau.

PubMed

Tuo, Dengfeng; Xu, Mingxiang; Gao, Guangyao

2018-08-15

Wind and water erosion are two dominant types of erosion that lead to soil and nutrient losses. Wind and water erosion may occur simultaneously to varying extents in semi-arid regions. The contributions of wind and water erosion to total erosion and their effects on soil quality, however, remains elusive. We used cesium-137 ( 137 Cs) inventories to estimate the total soil erosion and used the Revised Universal Soil Loss Equation (RUSLE) to quantify water erosion in sloping croplands. Wind erosion was estimated from the subtraction of the two. We also used 137 Cs inventories to calculate total soil erosion and validate the relationships of the soil quality and erosion at different slope aspects and positions. The results showed that wind erosion (1460tkm -2 a -1 ) on northwest-facing slope was responsible for approximately 39.7% of the total soil loss, and water erosion (2216tkm -2 a -1 ) accounted for approximately 60.3%. The erosion rates were 58.8% higher on northwest- than on southeast-facing slopes. Northwest-facing slopes had lower soil organic carbon, total nitrogen, clay, and silt contents than southeast-facing slopes, and thus, the 137 Cs inventories were lower, and the total soil erosions were higher on the northwest-facing slopes. The variations in soil physicochemical properties were related to total soil erosion. The lowest 137 Cs inventories and nutrient contents were recorded at the upper positions on the northwest-facing slopes due to the successive occurrence of more severe wind and water erosion at the same site. The results indicated that wind and water could accelerate the spatial variability of erosion rate and soil properties and cause serious decreases in the nutrient contents in sloping fields. Our research could help researchers develop soil strategies to reduce soil erosion according to the dominant erosion type when it occurs in a hilly agricultural area. Copyright © 2018 Elsevier B.V. All rights reserved.

Estimating potential wind erosion of agricultural lands in northern China using the Revised Wind Erosion Equation (RWEQ) and GIS

USDA-ARS?s Scientific Manuscript database

Fine materials emissions from severe wind-induced soil erosion have multiple impacts on land degradation and environmental pollution in the agro-pastoral ecotone in northern China (APEC). Assessment of wind erosion for the agricultural land management systems in APEC are needed to determine which sy...

An extreme wind erosion event of the fresh Eyjafjallajökull 2010 volcanic ash

PubMed Central

Arnalds, Olafur; Thorarinsdottir, Elin Fjola; Thorsson, Johann; Waldhauserova, Pavla Dagsson; Agustsdottir, Anna Maria

2013-01-01

Volcanic eruptions can generate widespread deposits of ash that are subsequently subjected to erosive forces which causes detrimental effects on ecosystems. We measured wind erosion of the freshly deposited Eyjafjallajökull ash at a field site the first summer after the 2010 eruption. Over 30 wind erosion events occurred (June-October) at wind speeds > 10 m s−1 in each storm with gusts up to 38.7 m s−1. Surface transport over one m wide transect (surface to 150 cm height) reached > 11,800 kg m−1 during the most intense storm event with a rate of 1,440 kg m−1 hr−1 for about 6½ hrs. This storm is among the most extreme wind erosion events recorded on Earth. The Eyjafjallajökull wind erosion storms caused dust emissions extending several hundred km from the volcano affecting both air quality and ecosystems showing how wind erosion of freshly deposited ash prolongs impacts of volcanic eruptions. PMID:23409248

An extreme wind erosion event of the fresh Eyjafjallajökull 2010 volcanic ash.

PubMed

Arnalds, Olafur; Thorarinsdottir, Elin Fjola; Thorsson, Johann; Waldhauserova, Pavla Dagsson; Agustsdottir, Anna Maria

2013-01-01

Volcanic eruptions can generate widespread deposits of ash that are subsequently subjected to erosive forces which causes detrimental effects on ecosystems. We measured wind erosion of the freshly deposited Eyjafjallajökull ash at a field site the first summer after the 2010 eruption. Over 30 wind erosion events occurred (June-October) at wind speeds > 10 m s(-1) in each storm with gusts up to 38.7 m s(-1). Surface transport over one m wide transect (surface to 150 cm height) reached > 11,800 kg m(-1) during the most intense storm event with a rate of 1,440 kg m(-1) hr(-1) for about 6½ hrs. This storm is among the most extreme wind erosion events recorded on Earth. The Eyjafjallajökull wind erosion storms caused dust emissions extending several hundred km from the volcano affecting both air quality and ecosystems showing how wind erosion of freshly deposited ash prolongs impacts of volcanic eruptions.

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.

Cropping system effects on wind erosion potential

USDA-ARS?s Scientific Manuscript database

Wind erosion of soil is a destructive process impacting crop productivity and human health and safety. The mechanics of wind erosion and soil properties that influence erosion are well understood. Less well-studied are the effects that cropping intensity has upon those soil properties. We collected ...

[Influences of land using patterns on the anti-wind erosion of meadow grassland].

PubMed

Zhou, Yao-Zhi; Wang-Xu; Yang, Gui-Xia; Xin, Xiao-Ping

2008-05-01

In order to analyse the effects of the human disturbances to the ability of anti-wind erosion of the Hulunbuir meadow grassland, the methods of vegetation investigation and the wind tunnel experiment were made to research the changes of vegetation and the abilities of anti-wind erosion of meadow grassland under different using patterns of meadow grassland. The results indicate that, under different grazing intensities of meadow grassland, the critical wind velocity of soil erosion (v) changes with the vegetation cover according to the relation of second power function. Along with the grazing intensities increasing and the vegetation cover reducing, the velocity of soil erosion rapidly increased on the condition of similar wind velocity which is speedier than the critical wind velocity of soil erosion. When the meadow grassland is mildly grazed which the vegetation cover maintains 63%, the velocity of soil erosion is small even there is gale that the wind velocity reach 25 m/s. When the vegetation cover of meadow grassland reduced to less than 35%, the velocity of soil erosion rapidly increased with the vegetation cover's reducing on the condition of the wind velocity is among 20-25 m/s. And owing to the no-tillage cropland of meadow grassland is completely far from the protection of the vegetation, the soil wind erosion quantity achieves 682.1 kg/hm2 in a minute when the wind velocity is 25 m/s, which approaches the average formation quantity of soil (1 000 kg/hm2) in a year.

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.

Wind erosion in semiarid landscapes: Predictive models and remote sensing methods for the influence of vegetation

NASA Technical Reports Server (NTRS)

Musick, H. Brad

1993-01-01

The objectives of this research are: to develop and test predictive relations for the quantitative influence of vegetation canopy structure on wind erosion of semiarid rangeland soils, and to develop remote sensing methods for measuring the canopy structural parameters that determine sheltering against wind erosion. The influence of canopy structure on wind erosion will be investigated by means of wind-tunnel and field experiments using structural variables identified by the wind-tunnel and field experiments using model roughness elements to simulate plant canopies. The canopy structural variables identified by the wind-tunnel and field experiments as important in determining vegetative sheltering against wind erosion will then be measured at a number of naturally vegetated field sites and compared with estimates of these variables derived from analysis of remotely sensed data.

Simulation model of erosion and deposition on a barchan dune

NASA Technical Reports Server (NTRS)

Howard, A. D.; Morton, J. B.; Gal-El-hak, M.; Pierce, D. B.

1977-01-01

Erosion and deposition over a barchan dune near the Salton Sea, California, are modeled by bookkeeping the quantity of sand in saltation following streamlines of transport. Field observations of near surface wind velocity and direction plus supplemental measurements of the velocity distribution over a scale model of the dune are combined as input to Bagnold type sand transport formulas corrected for slope effects. A unidirectional wind is assumed. The resulting patterns of erosion and deposition compare closely with those observed in the field and those predicted by the assumption of equilibrium (downwind translation of the dune without change in size or geometry). Discrepancies between the simulated results and the observed or predicted erosional patterns appear to be largely due to natural fluctuations in the wind direction. The shape of barchan dunes is a function of grain size, velocity, degree of saturation of the oncoming flow, and the variability in the direction of the oncoming wind. The size of the barchans may be controlled by natural atmospheric scales, by the age of the dunes, or by the upwind roughness. The upwind roughness can be controlled by fixed elements or by sand in the saltation. In the latter case, dune scale is determined by grain size and wind velocity.

Multi-scale wind erosion monitoring and assessment for US rangelands

USDA-ARS?s Scientific Manuscript database

Wind erosion is a major resource concern for rangeland managers. Although wind erosion is a naturally occurring process in many drylands, land use activities, and land management in particular, can accelerate wind-driven soil loss – impacting ecosystem dynamics and agricultural production, air quali...

Wind Tunnel Experiments: Influence of Erosion and Deposition on Wind-Packing of New Snow

NASA Astrophysics Data System (ADS)

Sommer, C.; Fierz, C. G.; Lehning, M.

2017-12-01

We observed the formation of wind crusts in wind tunnel experiments. A SnowMicroPen was used to measure the hardness profile of the snow and a Microsoft Kinect provided distributed snow depth data. Earlier experiments showed that no crust forms without saltation and that the dynamics of erosion and deposition may be a key factor to explain wind-packing. The Kinect data could be used to quantify spatial erosion and deposition patterns and the combination with the SnowMicroPen data allowed to study the effect of erosion and deposition on wind-hardening. We found that erosion had no hardening effect on fresh snow and that deposition is a necessary but not sufficient condition for wind crust formation. Deposited snow was only hardened in wind-exposed areas. The Kinect data was used to calculate the wind-exposure parameter Sx. We observed no significant hardening for Sx>0.25. The variability of resulting wind crust hardnesses at Sx<0.25 was still large, however.

Evaluation of Interrill Erosion Under Wind-Driven Rain Events in Northern Burkina Faso

USDA-ARS?s Scientific Manuscript database

Wind changes the velocity, frequency and angle of raindrop impact and hence affects rain splash detachment rates. Many soil erosion models underpredict interrill erosion because the contribution of the wind to raindrop detachment and wind-driven transport processes are not taken into account. In thi...

Early-season wind erosion influenced by soil-incorporated green manure in the Pacific Northwest

USDA-ARS?s Scientific Manuscript database

Management strategies are sought to minimize wind erosion of irrigated agricultural soils along the Columbia River of the Inland Pacific Northwest, particularly during the early season (March-April) when high winds coincide with sowing of vegetable crops. Early-season wind erosion potential from soi...

Estimation of wind erosion from construction of a railway in arid northwest China

USDA-ARS?s Scientific Manuscript database

A state-of-the-art wind erosion simulation model, the Wind Erosion Prediction System and the United States Environmental Protection Agency’s AP-42 emission factors formula, were combined together to evaluate wind-blown dust emissions from various construction units from a railway construction projec...

Depletion and Redistribution of Soil Nutrients in Response to Wind Erosion in Desert Grasslands of the Southwestern United States

NASA Astrophysics Data System (ADS)

Li, J.; Okin, G.; Hartman, L.; Epstein, H.

2005-12-01

Wind is a key abiotic factor that determines the spatial distribution of soil nutrients in arid grasslands with large unvegetated gaps, such as those found in the southwestern US. On the landscape scale, basic relationships such as wind erosion rate vs. vegetative cover, and soil nutrient removal rate vs. vegetative cover have not yet been extensively studied. In a series of experiments conducted in the Jornada Experimental Range near Las Cruces, New Mexico, we have examined these relationships to determine the impact of wind erosion and dust emission on pools of soil nutrients. In the experiments, varying levels of cover were achieved by vegetation removal on 25 m x 50 m plots. Intense surface soil sampling was conducted to monitor spatial distribution of soil nutrients. Large numbers of aeolian sediment samplers were installed to obtain estimates of vertical and horizontal dust flux. Available data from one wind erosion season show that: 1) total organic C (TOC) and total N (TN) content in the windblown sediment collected at the height of 1 m were 2.2 to 7.2 times larger than those of nutrients in the surface soil (enrichment ratio); 2) enrichment ratio generally increases with the increase of vegetative cover, indicating biotic processes continually add nutrients to surface soil in high-cover treatments, while nutrients are depleted in low-cover treatments; 3) average horizontal mass flux is 12 times larger in the bare plot than in the control plot, indicating the extreme importance of vegetative cover in protecting soil nutrient loss caused by wind erosion; 4) detectable soil nutrient depletion happened within one windy season in plots with vegetation removal, especially for TOC and TN, reflecting the importance of biotic processes in maintaining nutrient pools in the surface soil; and, 5) after only a single windy season, wind erosion can significantly alter the spatial pattern of soil nutrients.

7 CFR 610.13 - Equations for predicting soil loss due to wind erosion.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 6 2014-01-01 2014-01-01 false Equations for predicting soil loss due to wind erosion... RESOURCES CONSERVATION SERVICE, DEPARTMENT OF AGRICULTURE CONSERVATION OPERATIONS TECHNICAL ASSISTANCE Soil Erosion Prediction Equations § 610.13 Equations for predicting soil loss due to wind erosion. (a) The...

7 CFR 610.13 - Equations for predicting soil loss due to wind erosion.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 6 2010-01-01 2010-01-01 false Equations for predicting soil loss due to wind erosion... RESOURCES CONSERVATION SERVICE, DEPARTMENT OF AGRICULTURE CONSERVATION OPERATIONS TECHNICAL ASSISTANCE Soil Erosion Prediction Equations § 610.13 Equations for predicting soil loss due to wind erosion. (a) The...

7 CFR 610.13 - Equations for predicting soil loss due to wind erosion.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 6 2012-01-01 2012-01-01 false Equations for predicting soil loss due to wind erosion... RESOURCES CONSERVATION SERVICE, DEPARTMENT OF AGRICULTURE CONSERVATION OPERATIONS TECHNICAL ASSISTANCE Soil Erosion Prediction Equations § 610.13 Equations for predicting soil loss due to wind erosion. (a) The...

7 CFR 610.13 - Equations for predicting soil loss due to wind erosion.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 6 2011-01-01 2011-01-01 false Equations for predicting soil loss due to wind erosion... RESOURCES CONSERVATION SERVICE, DEPARTMENT OF AGRICULTURE CONSERVATION OPERATIONS TECHNICAL ASSISTANCE Soil Erosion Prediction Equations § 610.13 Equations for predicting soil loss due to wind erosion. (a) The...

7 CFR 610.13 - Equations for predicting soil loss due to wind erosion.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 6 2013-01-01 2013-01-01 false Equations for predicting soil loss due to wind erosion... RESOURCES CONSERVATION SERVICE, DEPARTMENT OF AGRICULTURE CONSERVATION OPERATIONS TECHNICAL ASSISTANCE Soil Erosion Prediction Equations § 610.13 Equations for predicting soil loss due to wind erosion. (a) The...

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

Erosion of carbon/carbon by solar wind charged particle radiation during a solar probe mission

NASA Technical Reports Server (NTRS)

Sokolowski, Witold; O'Donnell, Tim; Millard, Jerry

1991-01-01

The possible erosion of a carbon/carbon thermal shield by solar wind-charged particle radiation is reviewed. The present knowledge of erosion data for carbon and/or graphite is surveyed, and an explanation of erosion mechanisms under different charged particle environments is discussed. The highest erosion is expected at four solar radii. Erosion rates are analytically estimated under several conservative assumptions for a normal quiet and worst case solar wind storm conditions. Mass loss analyses and comparison studies surprisingly indicate that the predicted erosion rate by solar wind could be greater than by nominal free sublimation during solar wind storm conditions at four solar radii. The predicted overall mass loss of a carbon/carbon shield material during the critical four solar radii flyby can still meet the mass loss mission requirement of less than 0.0025 g/sec.

Wind erosion potential of a winter wheat–summer fallow rotation after land application of biosolids

USDA-ARS?s Scientific Manuscript database

While land application of biosolids is recognized as a sustainable management practice for enhancing soil health, no studies have determined the effects of biosolids on soil wind erosion. Wind erosion potential of a silt loam was assessed using a portable wind tunnel after applying synthetic and bio...

Enhancing wind erosion monitoring and assessment for U.S. rangelands

USGS Publications Warehouse

Webb, Nicholas P.; Van Zee, Justin W.; Karl, Jason W.; Herrick, Jeffrey E.; Courtright, Ericha M.; Billings, Benjamin J.; Boyd, Robert C.; Chappell, Adrian; Duniway, Michael C.; Derner, Justin D.; Hand, Jenny L.; Kachergis, Emily; McCord, Sarah E.; Newingham, Beth A.; Pierson, Frederick B.; Steiner, Jean L.; Tatarko, John; Tedela, Negussie H.; Toledo, David; Van Pelt, R. Scott

2017-01-01

On the GroundWind erosion is a major resource concern for rangeland managers because it can impact soil health, ecosystem structure and function, hydrologic processes, agricultural production, and air quality.Despite its significance, little is known about which landscapes are eroding, by how much, and when.The National Wind Erosion Research Network was established in 2014 to develop tools for monitoring and assessing wind erosion and dust emissions across the United States.The Network, currently consisting of 13 sites, creates opportunities to enhance existing rangeland soil, vegetation, and air quality monitoring programs.Decision-support tools developed by the Network will improve the prediction and management of wind erosion across rangeland ecosystems.

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

PubMed

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

2013-07-01

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

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.

Advances in wind erosion modelling in Europe

NASA Astrophysics Data System (ADS)

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

2017-04-01

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

[Estimation of the effect derived from wind erosion of soil and dust emission in Tianjin suburbs on the central district based on WEPS model].

PubMed

Chen, Li; Han, Ting-Ting; Li, Tao; Ji, Ya-Qin; Bai, Zhi-Peng; Wang, Bin

2012-07-01

Due to the lack of a prediction model for current wind erosion in China and the slow development for such models, this study aims to predict the wind erosion of soil and the dust emission and develop a prediction model for wind erosion in Tianjin by investigating the structure, parameter systems and the relationships among the parameter systems of the prediction models for wind erosion in typical areas, using the U.S. wind erosion prediction system (WEPS) as reference. Based on the remote sensing technique and the test data, a parameter system was established for the prediction model of wind erosion and dust emission, and a model was developed that was suitable for the prediction of wind erosion and dust emission in Tianjin. Tianjin was divided into 11 080 blocks with a resolution of 1 x 1 km2, among which 7 778 dust emitting blocks were selected. The parameters of the blocks were localized, including longitude, latitude, elevation and direction, etc.. The database files of blocks were localized, including wind file, climate file, soil file and management file. The weps. run file was edited. Based on Microsoft Visualstudio 2008, secondary development was done using C + + language, and the dust fluxes of 7 778 blocks were estimated, including creep and saltation fluxes, suspension fluxes and PM10 fluxes. Based on the parameters of wind tunnel experiments in Inner Mongolia, the soil measurement data and climate data in suburbs of Tianjin, the wind erosion module, wind erosion fluxes, dust emission release modulus and dust release fluxes were calculated for the four seasons and the whole year in suburbs of Tianjin. In 2009, the total creep and saltation fluxes, suspension fluxes and PM10 fluxes in the suburbs of Tianjin were 2.54 x 10(6) t, 1.25 x 10(7) t and 9.04 x 10(5) t, respectively, among which, the parts pointing to the central district were 5.61 x 10(5) t, 2.89 x 10(6) t and 2.03 x 10(5) t, respectively.

Windblown Dust and Air Quality Under a Changing Climate in the Pacific Northwest

NASA Astrophysics Data System (ADS)

Sharratt, B. S.; Tatarko, J.; Abatzoglou, J. T.; Fox, F.; Huggins, D. R.

2016-12-01

Wind erosion is a concern for sustainable agriculture and societal health in the US Pacific Northwest. Indeed, wind erosion continues to cause exceedances of the National Ambient Air Quality Standard for PM10 in the region. Can we expect air quality to deteriorate or improve as climate changes? Will wind erosion escalate in the future under a warmer and drier climate as forecast for Australia, southern prairies of Canada, northern China, and United States Corn Belt and Colorado Plateau? To answer these questions, we used 18 global climate models, cropping systems simulation model (CropSyst), and the Wind Erosion Prediction System (WEPS) to simulate the complex interactions among climate, crop production, and wind erosion. These simulations were carried out in eastern Washington where wind erosion of agricultural lands contribute to poor air quality in the region. Our results suggest that an increase in temperature and CO2 concentration, coupled with nominal increases in precipitation, will enhance biomass production and reduce soil and PM10 losses by the mid-21st century. This study reveals that climate change may reduce the risk of wind erosion and improve air quality in the Inland Pacific Northwest.

Use of dust storm observations on satellite images to identify areas vulnerable to severe wind erosion

USGS Publications Warehouse

Breed, C.S.; McCauley, J.F.

1986-01-01

Blowing dust is symptomatic of severe wind erosion and deterioration of soils in areas undergoing dessication and/or devegetation. Dust plumes on satellite images can commonly be traced to sources in marginally arable semiarid areas where protective lag gravels or vegetation have been removed and soils are dry, as demonstrated for the Portales Valley, New Mexico. Images from Landsat and manned orbiters such as Skylab and the Space Shuttle are useful for illustrating the regional relations of airborne dust plumes to source areas. Geostationary satellites such as GOES are useful in tracking the time-histories of episodic dust storms. These events sometimes go unrecognized by weather observers and are the precursors of long-term land degradation trends. In areas where soil maps and meteorological data are inadequate, satellite images provide a means for identifying problem areas where measures are needed to control or mitigate wind erosion. ?? 1986 D. Reidel Publishing Company.

Research of wind erosion intensity in the region of Subotica-Horgos sands

Treesearch

Velizar Velasevic; Ljubomir Letic

1991-01-01

Wind is an important erosional process in the areas of steppe-savanna climate in Europe as typified by the Bojvodina plain in Yugoslavia. Cultivated and forested plots on the Subotica-Horgos Sands were used to study aeolian erosion processes. Wind erosion on the cultivated plot was 3-29 times greater than that occurring on a plot planted to forest trees. That erosion...

Wind erosion potential following application of biosolids

USDA-ARS?s Scientific Manuscript database

The application of biosolids to agricultural land has the potential to improve soil health and crop production. These benefits could also possibly reduce the threat of wind erosion in arid and semiarid regions. Therefore, we assessed the impact of biosolids on wind erosion of agricultural land at Li...

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 Reduction of Partitioned Wind and Water Erosion by Conservation Agriculture

USDA-ARS?s Scientific Manuscript database

Soil loss due to wind and water erosion degrades the soil and results in environmental problems downstream and downwind of the source field. Wind and water erosion may both occur to varying extents particularly in semi-arid environments. Soil conservation strategies require information about the p...

A simple method to estimate threshold friction velocity of wind erosion in the field

USDA-ARS?s Scientific Manuscript database

Nearly all wind erosion models require the specification of threshold friction velocity (TFV). Yet determining TFV of wind erosion in field conditions is difficult as it depends on both soil characteristics and distribution of vegetation or other roughness elements. While several reliable methods ha...

Impacts of corn residue grazing and baling on wind erosion potential in a semiarid environment

USDA-ARS?s Scientific Manuscript database

Implications of corn (Zea mays L.) residue grazing and baling on wind erosion in integrated crop-livestock systems are not well understood. We studied: 1) soil properties affecting wind erosion potential including dry aggregate-size distribution, geometric mean diameter (GMDA), geometric standard de...

Critical role of wind-wave induced erosion on the morphodynamic evolution of shallow tidal basins

NASA Astrophysics Data System (ADS)

D'Alpaos, Andrea; Carniello, Luca; Rinaldo, Andrea

2014-05-01

Wind-wave induced erosion processes are among the chief processes which govern the morphodynamic evolution of shallow tidal basins, both in the vertical and in the horizontal plane. Wind-wave induced bottom shear stresses can promote the disruption of the polymeric microphytobenthic biofilm and lead to the erosion of tidal-flat surfaces and to the increase in suspended sediment concentration which affects the stability of intertidal ecosystems. Moreover, the impact of wind-waves on salt-marsh margins can lead to the lateral erosion of marsh boundaries thus promoting the disappearance of salt-marsh ecosystems. Towards the goal of developing a synthetic theoretical framework to represent wind wave-induced resuspension events and account for their erosional effects on the long-term biomorphodynamic evolution of tidal systems, we have employed a complete, coupled finite element model accounting for the role of wind waves and tidal currents on the hydrodynamic circulation in shallow basins. Our analyses of the characteristics of combined current and wave-induced exceedances in bottom shear stress over a given threshold for erosion, suggest that wind wave-induced resuspension events can be modeled as a marked Poisson process. The interarrival time of wave-induced erosion events is, in fact, an exponentially distributed random variable, as well as the duration and intensity of overthreshold events. Moreover, the analysis of wind-wave induced resuspension events for different historical configurations of the Venice Lagoon from the 19th to the 21st century, shows that the interarrival times of erosion events have dramatically decreased through the last two centuries, whereas the intensities of erosion events have experienced a surprisingly high increase. This allows us to characterize the threatening erosion and degradation processes that the Venice Lagoon has been experiencing since the beginning of the last century.

Effects of stubble and mulching on soil erosion by wind in semi-arid China.

PubMed

Cong, Peifei; Yin, Guanghua; Gu, Jian

2016-07-18

Soil erosion is a growing challenge for agricultural production in Northern China. To explore the effect of variation in stubble height and mulching biomass on soil erosion caused by wind, we conducted a field experiment using a quadratic rotation combination design. Results showed that the quantity of straw mulch was the dominant factor affecting soil erosion, and stubble height was of secondary importance. The soil water content in stubble and straw mulching treatments was higher than in a control treatment at 0-20 cm soil, and the tendency in the amount of soil water content was opposite to the amount of wind erosion (r = -0.882, n = 10, p < 0.01). The change in soil water content observed in the stubble and mulch treatments at the 15-20 cm depth was higher than the change from 0-5 cm to 5-10 cm. Combined, the influence of a stubble height of 34 cm and mulch quantity of 4260 kg·ha(-1) lowered the amount of erosion to 0.42 t·ha(-1), and increased the corn yield to 11900 kg·ha(-1). We determined that those were the most appropriate levels of stubble height and straw mulch for crop fields in the semi-arid regions of Northern China.

Application of the Wind Erosion Prediction System in the AIRPACT regional air quality modeling framework

USDA-ARS?s Scientific Manuscript database

Wind erosion of soil is a major concern of the agricultural community as it removes the most fertile part of the soil and thus degrades soil productivity. Furthermore, dust emissions due to wind erosion contribute to poor air quality, reduce visibility, and cause perturbations to regional radiation ...

A history of wind erosion prediction models in the United States Department of Agriculture: The Wind Erosion Prediction System (WEPS)

USDA-ARS?s Scientific Manuscript database

Development of the Wind Erosion Prediction System (WEPS) was officially inaugurated in 1985 by United States Department of Agriculture-Agricultural Research Service (USDA-ARS) scientists in response to customer requests, particularly those coming from the USDA Soil Conservation Service (SCS), for im...

AERO: A decision support tool for wind erosion assessment in rangelands and croplands

USDA-ARS?s Scientific Manuscript database

Wind erosion is a key driver of global land degradation, with on- and off-site impacts on agricultural production, air quality, ecosystem services and climate. Measuring rates of wind erosion and dust emission across land use and land cover types is important for quantifying the impacts and identify...

Wind erosion potential after land application of biosolids

NASA Astrophysics Data System (ADS)

PI, H.; Sharratt, B. S.; Schillinger, W. F.; Bary, A.; Cogger, C.

2017-12-01

The world population is currently 7.6 billion and, along with continued population growth, comes the challenge of disposing of wastewater and sewage sludge (biosolids). Applying biosolids to agricultural land to replace synthetic fertilizers represents a relatively safe method to recycle or sustainably use biosolids. While land application of biosolids is recognized as a sustainable management practice for enhancing soil health, no studies have determined the effects of biosolids on soil wind erosion. Wind erosion potential of a silt loam was assessed using a portable wind tunnel after applying synthetic and biosolid fertilizer to conventional and conservation tillage practices during the summer fallow phase of a winter wheat-summer fallow rotation in 2015 and 2016 in east-central Washington. Little difference in soil loss was observed between biosolid and synthetic fertilizer treatments, but this result appeared to be dependent on susceptibility of the soil to erosion. Regression analysis between soil loss from fertilizer or tillage treatments indicated that soil loss was lower from biosolid versus synthetic fertilizer and conservation versus conventional tillage at high erosion rates. This suggests that biosolids may reduce wind erosion under highly erodible conditions. Meanwhile, heavy metal concentrations in the windblown sediment were similar for the biosolid and synthetic fertilizer treatments whereas metal loss in windblown sediment was 10% lower from biosolid than synthetic fertilizer. Our results indicate that land application of biosolids did not accelerate the loss of metals or nutrients from soils during high winds. KeywordsLand application of biosolids; wind erosion; wind tunnel; sustainable agriculture

Reduction in soil aggregate size distribution due to wind erosion

NASA Astrophysics Data System (ADS)

Swet, Nitzan; Katra, Itzhak

2017-04-01

Soil erosion process by wind causes emission of fine soil particles, and thus alters the topsoil's properties, fertility, and erodibility. Topsoil resistance to erosion depends on its physicochemical properties, especially on the soil aggregation. Although the key role of aggregates in soil erodibility, quantitative information on the relations between soil aggregate size distribution (ASD) and erosion is still lucking. This study focuses on ASD analyses before and after soil erosion by wind. Wind tunnel experiments and soil analyses were conducted on semiarid loess topsoils with different initial conditions of aggregation. The results show that in all initial soil conditions saltation of sand particles caused the breakdown of macro-aggregates > 500 µm, resulting in increase of micro-aggregates (63-250 µm). The micro-aggregate production increases with the wind shear velocity (up to 0.61 m s-1) for soils with available macro-aggregates. The findings highlight dynamics in soil aggregation in response to erosion process, and therefore the significance of ASD in quantifying soil degradation and soil loss potential.

Cambrian rivers and floodplains: the significance of microbial cementation, groundwater and aeolian sediment transport

NASA Astrophysics Data System (ADS)

Reesink, A. J. H.; Best, J.; Freiburg, J. T.; Nathan, W.

2016-12-01

Rivers that existed before land plants colonized the Earth are commonly considered to be unaffected by microbial activity on their floodplains, because the limited cementation produced by microbial activity is insufficient to stabilize the river banks. Although this assumption is likely correct, such emphasis on channel dynamics ignores the potential role of floodplain dynamics as an integral component of the river system. Detailed analysis of cores from the Cambrian Mount Simon Sandstone, Illinois, suggests that a significant proportion of the terrestrial sequence is composed of flat-bedded `crinkly' structures that provide evidence of cementation by soil crusts and microbial biofilms, and that promoted the adhesion of sediment to sticky surfaces. Wind ripples and local desert pavements were abundant. These findings highlight that sediment deposition on Cambrian floodplains was often dominated by wind in locations where the ground water table reached the surface, and was thus likely independent of sediment transport within the river channel. Erosion by wind would thus have been hindered by surface cementation and the formation of desert pavements. Such ground water control on deposition, and resistance to erosion by floodplain surface hardening, appear to have been the primary controls on Cambrian floodplain topography. Because floodplain topography poses a key control on channel and floodplain flow, these processes may have affected patterns of erosion and deposition, as well as reach-scale dynamics such as channel avulsions. The autonomous operation of wind-and-groundwater controlled floodplains makes pre-vegetated river systems more sensitive to climatic conditions such as precipitation and evaporation, and strikingly different from those that occurred after the development of land plants.

A pan-European quantitative assessment of soil loss by wind

NASA Astrophysics Data System (ADS)

Borrelli, Pasqualle; Lugato, Emanuele; Panagos, Panos

2016-04-01

Soil erosion by wind is a serious environmental problem often low perceived but resulting in severe soil degradation forms. On the long-term a considerable part of topsoil - rich in nutrient and organic matters - could be removed compromising the agricultural productivity and inducing an increased use of fertilizers. Field scale studies and observations proven that wind erosion is a serious problem in many European sites. The state-of-the-art suggests a scenario where wind erosion locally affects the temperate climate areas of the northern European countries, as well as the semi-arid areas of the Mediterranean region. However, observations, field measurements and modelling assessments are extremely limited and unequally distributed across Europe. It implies a lack of knowledge about where and when wind erosion occurs, limiting policy actions aimed at mitigating land degradation. To gain a better understanding about soil degradation process, the Soil Resource Assessment working group of the Joint Research Centre carried out the first pan-European assessments of wind-erodible fraction of soil (EF) (Geoderma, 232, 471-478, 2014) and land susceptibility to wind erosion (Land Degradation & Development, DOI: 10.1002/ldr.2318). Today's challenge is to integrate the insights archived by these pan-European assessments, local experiments and field-scale models into a new generation of regional-scale wind erosion models. A GIS version of the Revised Wind Erosion Equation (RWEQ) was developed with the aim to i) move a step forward into the aforementioned challenges, and ii) evaluate the soil loss potential due to wind erosion in the agricoltural land of the EU. The model scheme was designed to describe daily soil loss potential, combining spatiotemporal conditions of soil erodibility, crust factor, soil moisture content, vegetation coverage and wind erosivity at 1 km2 resolution. The average soil loss predicted by GIS-RWEQ in the EU arable land ranges from 0 to 39.9 Mg ha-1 yr-1, with a mean value of 0.53 Mg ha-1 yr-1. A cross-country analysis shows highest mean annual soil loss values in Denmark (3 Mg ha-1 yr-1), the Netherland (2.6 Mg ha-1 yr-1), Bulgaria (1.8 Mg ha-1 yr-1) and to a lesser extent in the United Kingdom (1 Mg ha-1 yr-1) and Romania (0.95 Mg ha-1 yr-1). The cross-validation results provides encouraging outcomes in line with the local measurements reported by academic literature. Novel insights into the spatiotemporal dynamics of wind erosion processes have been achieved, providing knowledge and a tool to gain a more comprehensive understanding of wind erosion processes in Europe.

Shelter Index and a simple wind speed parameter to characterize vegetation control of sand transport threshold and Flu

NASA Astrophysics Data System (ADS)

Gillies, J. A.; Nield, J. M.; Nickling, W. G.; Furtak-Cole, E.

2014-12-01

Wind erosion and dust emissions occur in many dryland environments from a range of surfaces with different types and amounts of vegetation. Understanding how vegetation modulates these processes remains a research challenge. Here we present results from a study that examines the relationship between an index of shelter (SI=distance from a point to the nearest upwind vegetation/vegetation height) and particle threshold expressed as the ratio of wind speed measured at 0.45 times the mean plant height divided by the wind speed at 17 m when saltation commences, and saltation flux. The results are used to evaluate SI as a parameter to characterize the influence of vegetation on local winds and sediment transport conditions. Wind speed, wind direction, saltation activity and point saltation flux were measured at 35 locations in defined test areas (~13,000 m2) in two vegetation communities: mature streets of mesquite covered nebkhas and incipient nebkhas dominated by low mesquite plants. Measurement positions represent the most open areas, and hence those places most susceptible to wind erosion among the vegetation elements. Shelter index was calculated for each measurement position for each 10° wind direction bin using digital elevation models for each site acquired using terrestrial laser scanning. SI can show the susceptibility to wind erosion at different time scales, i.e., event, seasonal, or annual, but in a supply-limited system it can fail to define actual flux amounts due to a lack of knowledge of the distribution of sediment across the surface of interest with respect to the patterns of SI.

Wind erosion potential influenced by tillage in an irrigated potato-sweet corn rotation in the Columbia Basin

USDA-ARS?s Scientific Manuscript database

Wind erosion is a concern within the Columbia Basin of the Inland Pacific Northwest (PNW) United States due to the sandy texture of soils and small amount of residue retained on the soil surface after harvest of vegetable crops like potato. This study assessed potential wind erosion of an irrigated ...

75 FR 75961 - Notice of Implementation of the Wind Erosion Prediction System for Soil Erodibility System...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-07

... Wind Erosion Prediction System for Soil Erodibility System Calculations for the Natural Resources... Erosion Prediction System (WEPS) for soil erodibility system calculations scheduled for implementation for... computer model is a process-based, daily time-step computer model that predicts soil erosion via simulation...

Evaluating the effectiveness of agricultural mulches for reducing post-wildfire wind erosion

USDA-ARS?s Scientific Manuscript database

Post-wildfire soil erosion can be caused by water or aeolian processes yet most erosion research has focused on predominantly water-driven erosion. This study investigates the effectiveness of three agricultural mulches, with and without a tackifier, on aeolian sediment transport processes. A wind t...

Application of fuzzy logic approach for wind erosion hazard mapping in Laghouat region (Algeria) using remote sensing and GIS

NASA Astrophysics Data System (ADS)

Saadoud, Djouher; Hassani, Mohamed; Martin Peinado, Francisco José; Guettouche, Mohamed Saïd

2018-06-01

Wind erosion is one of the most serious environmental problems in Algeria that threatens human activities and socio-economic development. The main goal of this study is to apply a fuzzy logic approach to wind erosion sensitivity mapping in the Laghouat region, Algeria. Six causative factors, obtained by applying fuzzy membership functions to each used parameter, are considered: soil, vegetation cover, wind factor, soil dryness, land topography and land cover sensitivity. Different fuzzy operators (AND, OR, SUM, PRODUCT, and GAMMA) are applied to generate wind-erosion hazard map. Success rate curves reveal that the fuzzy gamma (γ) operator, with γ equal to 0.9, gives the best prediction accuracy with an area under curve of 85.2%. The resulting wind-erosion sensitivity map delineates the area into different zones of five relative sensitivity classes: very high, high, moderate, low and very low. The estimated result was verified by field measurements and the high statistically significant value of a chi-square test.

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.

Simulated effects of crop rotations and residue management on wind erosion in Wuchuan, west-central Inner Mongolia, China.

PubMed

Wang, Erda; Harman, Wyatte L; Williams, Jimmy R; Xu, Cheng

2002-01-01

For decades, wind erosion has triggered dust and sand storms, buffeting Beijing and areas of northwestern China to the point of being hazardous to human health while rapidly eroding crop and livestock productivity. The EPIC (Environmental Policy Integrated Climate) field-scale simulation model was used to assess long-term effects of improved crop rotations and crop residue management practices on wind erosion in Wuchuan County in Inner Mongolia. Simulation results indicate that preserving crop stalks until land is prepared by zone tillage for the next year's crop in lieu of using them as a source of heating fuel or livestock fodder significantly reduces wind erosion by 60%. At the same time, grain and potato (Solanum tuberosum L.) yields were maintained or improved. Significant reductions in erosion, 35 to 46%, also resulted from delaying stalk removal until late January through late April. Yearly wind erosion was concentrated in April and May, the windiest months. Additionally, the use of alternative crop rotations resulted in differences in wind erosion, largely due to a difference in residue stature and quality and differences in biomass produced. As a result, altering current crop rotation systems by expanding corn (Zea mays L.), wheat (Triticum aestivum L.), and millet [Sorghum bicolor (L.) Moench] and reducing potato and pea (Pisum sativum L.) production significantly reduced simulated wind erosion, thus diminishing the severity of dust and sand storms in northwestern China. Saving and protecting topsoil over time will sustain land productivity and have long-term implications for improving conditions of rural poverty in the region.

The Dust Storm Index (DSI): A method for monitoring broadscale wind erosion using meteorological records

NASA Astrophysics Data System (ADS)

O'Loingsigh, T.; McTainsh, G. H.; Tews, E. K.; Strong, C. L.; Leys, J. F.; Shinkfield, P.; Tapper, N. J.

2014-03-01

Wind erosion of soils is a natural process that has shaped the semi-arid and arid landscapes for millennia. This paper describes the Dust Storm Index (DSI); a methodology for monitoring wind erosion using Australian Bureau of Meteorology (ABM) meteorological observational data since the mid-1960s (long-term), at continental scale. While the 46 year length of the DSI record is its greatest strength from a wind erosion monitoring perspective, there are a number of technical challenges to its use because when the World Meteorological Organisation (WMO) recording protocols were established the use of the data for wind erosion monitoring was never intended. Data recording and storage protocols are examined, including the effects of changes to the definition of how observers should interpret and record dust events. A method is described for selecting the 180 long-term ABM stations used in this study and the limitations of variable observation frequencies between stations are in part resolved. The rationale behind the DSI equation is explained and the examples of temporal and spatial data visualisation products presented include; a long term national wind erosion record (1965-2011), continental DSI maps, and maps of the erosion event types that are factored into the DSI equation. The DSI is tested against dust concentration data and found to provide an accurate representation of wind erosion activity. As the ABM observational records used here were collected according to WMO protocols, the DSI methodology could be used in all countries with WMO-compatible meteorological observation and recording systems.

Design, construction and calibration of a portable boundary layer wind tunnel for field use

USDA-ARS?s Scientific Manuscript database

Wind tunnels have been used for several decades to study wind erosion processes. Portable wind tunnels offer the advantage of testing natural surfaces in the field, but they must be carefully designed to insure that a logarithmic boundary layer is formed and that wind erosion processes may develop ...

Mechanics of aeolian processes: Soil erosion and dust production

NASA Technical Reports Server (NTRS)

Mehrabadi, M. M.

1989-01-01

Aeolian (wind) processes occur as a result of atmosphere/land-surface system interactions. A thorough understanding of these processes and their physical/mechanical characterization on a global scale is essential to monitoring global change and, hence, is imperative to the fundamental goal of the Earth observing system (Eos) program. Soil erosion and dust production by wind are of consequence mainly in arid and semi arid regions which cover 36 percent of the Earth's land surface. Some recent models of dust production due to wind erosion of agricultural soils and the mechanics of wind erosion in deserts are reviewed and the difficulties of modeling the aeolian transport are discussed.

Soil Erosion. LC Science Tracer Bullet.

ERIC Educational Resources Information Center

Buydos, John F., Comp.

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

Performance of the SWEEP model affected by estimates of threshold friction velocity

USDA-ARS?s Scientific Manuscript database

The Wind Erosion Prediction System (WEPS) is a process-based model and needs to be verified under a broad range of climatic, soil, and management conditions. Occasional failure of the WEPS erosion submodel (Single-event Wind Erosion Evaluation Program or SWEEP) to simulate erosion in the Columbia Pl...

Desert winds: Monitoring wind-related surface processes in Arizona, New Mexico, and California

USGS Publications Warehouse

Breed, Carol S.; Reheis, Marith C.

1999-01-01

The 18-year Desert Winds Project established instrumented field sites in the five major regions of the North American Desert to obtain meteorological, geological, and vegetation data for natural desert sites affected by wind erosion. The eight chapters in this volume describe the settings and operation of the stations and summarize eolian-related research to date around the stations. The report includes studies of the sand-moving effectiveness of storm winds, wind-erosion susceptibility of different ground-surface types, relations of dust storms to meteorological conditions, mediation of wind erosion by vegetation, remote sensing to detect vegetation changes related to climate change, and comparison of regional dust deposition to that near Owens (dry) Lake.

In-situ erosion of cohesive sediment in a large shallow lake experiencing long-term decline in wind speed

NASA Astrophysics Data System (ADS)

Wu, Tingfeng; Timo, Huttula; Qin, Boqiang; Zhu, Guangwei; Janne, Ropponen; Yan, Wenming

2016-08-01

In order to address the major factors affecting cohesive sediment erosion using high-frequency in-situ observations in Lake Taihu, and the response of this erosion to long-term decline in wind speed, high-frequency meteorological, hydrological and turbidity sensors were deployed to record continuous field wind-induced wave, current and sediment erosion processes; Statistical analyses and mathematic modeling spanning 44 years were also conducted. The results revealed that the unconsolidated surficial cohesive sediment frequently experiences the processes of erosion, suspension and deposition. Wind waves, generated by the absorption of wind energy, are the principal force driving this cycle. When the wavelength-to-water depth ratio (L/D) is 2-3, wave propagation is affected by lakebed friction and surface erosion occurs. When L/D > 3, the interaction between wave and lakebed increases to induce massive erosion. However, influenced by rapid urbanization in the Lake Taihu basin, wind speed has significantly decreased, by an average rate of -0.022 m s-1 a-1, from 1970 to 2013. This has reduced the erodible area, represented by simulated L/D, at a rate of -16.9 km2 a-1 in the autumn and winter, and -8.1 km2 a-1 in the spring and summer. This significant decrease in surface erosion area, and the near disappearance of areas experiencing massive erosion, imply that Lake Taihu has become calmer, which can be expected to have adverse effects on the lake ecosystem by increasing eutrophication and nuisance cyanobacteria blooms.

Wind-driven rain and its implications for natural hazard management

NASA Astrophysics Data System (ADS)

Marzen, Miriam; Iserloh, Thomas; de Lima, João L. M. P.; Fister, Wolfgang; Ries, Johannes B.

2017-04-01

Prediction and risk assessment of hydrological extremes are great challenges. Following climate predictions, frequent and violent rainstorms will become a new hazard to several regions in the medium term. Particularly agricultural soils will be severely threatened due to the combined action of heavy rainfall and accompanying winds on bare soil surfaces. Basing on the general underestimation of the effect of wind on rain erosion, conventional soil erosion measurements and modeling approaches lack related information to adequately calculate its impact. The presented experimental-empirical approach shows the powerful impact of wind on the erosive potential of rain. The tested soils had properties that characterise three different environments 1. Silty loam of semi-arid Mediterranean dryfarming and fallow, 2. clayey loam of humid agricultural sites and 3. cohesionless sandy substrates as found at coasts, dune fields and drift-sand areas. Erosion was found to increase by a factor of 1.3 to 7.1, depending on site characteristics. Complementary tests with a laboratory procedure were used to quantify explicitly the effect of wind on raindrop erosion as well as the influence of substrate, surface structure and slope on particle displacement. These tests confirmed the impact of wind-driven rain on total erosion rates to be of great importance when compared to all other tested factors. To successfully adapt soil erosion models to near-future challenges of climate change induced rain storms, wind-driven rain is supposed to be introduced into the hazard management agenda.

Wind and Rock

NASA Image and Video Library

2011-03-09

This image from NASA Mars Odyssey is located west of Zephyria Planum. Surfaces in this region have undergone extensive erosion by the wind. Wind is one of the most active processes of erosion on the surface of Mars today.

Remote sensing of land use/cover changes and its effect on wind erosion potential in southern Iran

PubMed Central

Sameni, Abdolmajid; Fallah Shamsi, Seyed Rashid; Bartholomeus, Harm

2016-01-01

Wind erosion is a complex process influenced by different factors. Most of these factors are stable over time, but land use/cover and land management practices are changing gradually. Therefore, this research investigates the impact of changing land use/cover and land management on wind erosion potential in southern Iran. We used remote sensing data (Landsat ETM+ and Landsat 8 imagery of 2004 and 2013) for land use/cover mapping and employed the Iran Research Institute of Forest and Rangeland (IRIFR) method to estimate changes in wind erosion potential. For an optimal mapping, the performance of different classification algorithms and input layers was tested. The amount of changes in wind erosion and land use/cover were quantified using cross-tabulation between the two years. To discriminate land use/cover related to wind erosion, the best results were obtained by combining the original spectral bands with synthetic bands and using Maximum Likelihood classification algorithm (Kappa Coefficient of 0.8 and 0.9 for Landsat ETM+ and Landsat 8, respectively). The IRIFR modelling results indicate that the wind erosion potential has increased over the last decade. The areas with a very high sediment yield potential have increased, whereas the areas with a low, medium, and high sediment yield potential decreased. The area with a very low sediment yield potential have remained constant. When comparing the change in erosion potential with land use/cover change, it is evident that soil erosion potential has increased mostly in accordance with the increase of the area of agricultural practices. The conversion of rangeland to agricultural land was a major land-use change which lead to more agricultural practices and associated soil loss. Moreover, results indicate an increase in sandification in the study area which is also a clear evidence of increasing in soil erosion. PMID:27547511

Post-wildfire wind erosion in and around the Idaho National Laboratory Site

USGS Publications Warehouse

Germino, Matthew J.

2012-01-01

Wind erosion following large wildfires on and around the INL Site is a recurrent threat to human health and safety, DOE operations and trafficability, and ecological and hydrological condition of the INL Site and down-wind landscapes. Causes and consequences of wind erosion are mainly known from warm deserts (e.g., Southwest U.S.), dunefields, and croplands, and some but not all findings are transferable to the cold desert environments such as where the INL Site lies.

Stellar wind erosion of protoplanetary discs

NASA Astrophysics Data System (ADS)

Schnepf, N. R.; Lovelace, R. V. E.; Romanova, M. M.; Airapetian, V. S.

2015-04-01

An analytic model is developed for the erosion of protoplanetary gas discs by high-velocity magnetized stellar winds. The winds are centrifugally driven from the surface of rapidly rotating, strongly magnetized young stars. The presence of the magnetic field in the wind leads to Reynolds numbers sufficiently large to cause a strongly turbulent wind/disc boundary layer which entrains and carries away the disc gas. The model uses the conservation of mass and momentum in the turbulent boundary layer. The time-scale for significant erosion depends on the disc accretion speed, disc accretion rate, the wind mass-loss rate, and the wind velocity. The time-scale is estimated to be ˜2 × 106 yr. The analytic model assumes a steady stellar wind with mass- loss rate dot {M}}_w ˜ 10^{-10} M_{⊙} yr-1 and velocity vw ˜ 103 km s-1. A significant contribution to the disc erosion can come from frequent powerful coronal mass ejections (CMEs) where the average mass-loss rate in CMEs, dot{M}_CME, and velocities, vCME, have values comparable to those for the steady wind.

Mariner 9 evidence for wind erosion in the equatorial and mid-latitude regions of Mars

NASA Technical Reports Server (NTRS)

Mccauley, J. F.

1973-01-01

Evidence for extensive wind erosion principally in the equatorial and mid-latitude regions of Mars is presented and compared with selected erosional landforms from the coastal desert of Peru known to be of eolian origin. The evidence for widespread erosion on Mars prompted an examination of certain aspects of its wind regime that are thought to be significant geologically.

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

USDA-ARS?s Scientific Manuscript database

The Great Plains experienced an influx of settlers in the late 1850s to 1900. Periodic drought was hard on both settlers and the soil and caused severe wind erosion. The period known as the Dirty Thirties, 1931 to 1939, produced many severe windstorms, and the resulting dusty sky over Washington, D....

Nutrient and dust enrichment in Danish wind erosion sediments for different tillage directions

NASA Astrophysics Data System (ADS)

Mohammadian Behbahani, Ali; Fister, Wolfgang; Heckrath, Goswin; Kuhn, Nikolaus J.

2015-04-01

More than 80% of the soil types in Denmark have a sandy texture. Denmark is also subject to strong offshore and onshore winds, therefore, Danish soils are considered especially vulnerable to wind erosion. Where conventional tillage operations are applied on poorly aggregated soils, tillage ridges are more or less the only roughness element that can be used to protect soils against wind erosion until crop plants are large enough to provide sufficient breaks. Since wind erosion is a selective process, it can be assumed that increasing erosion rates are associated with increasing loss of dust sized particles and nutrients. However, selective erosion is strongly affected by the orientation and respective trapping efficiency of tillage ridges and furrows. The main objective of this study, therefore, was to determine the effect of tillage direction on nutrient mobilization by wind erosion from agricultural land in Denmark. In order to assess the relationship between the enrichment ratio of specific particle sizes and the amount of eroded nutrients, three soils with loamy sand texture, but varying amounts of sand-sized particles, were selected. In addition, a soil with slightly less sand, but much higher organic matter content was chosen. The soils were tested with three different soil surface scenarios (flat surface, parallel tillage, perpendicular tillage) in a wind tunnel simulation. The parallel tillage operation experienced the greatest erosion rates, independent of soil type. Particles with D50 between 100-155 µm showed the greatest risk of erosion. However, due to a greater loss of dust sized particles from perpendicularly tilled surfaces, this wind-surface arrangement showed a significant increase in nutrient enrichment ratio compared to parallel tillage and flat surfaces. The main reason for this phenomenon is most probably the trapping of larger particles in the perpendicular furrows. This indicates that the highest rate of soil protection does not necessarily coincide with lowest soil nutrient losses and dust emissions. For the evaluation of protection measures on these soil types in Denmark it is, therefore, important to differentiate between their effectivity to reduce total soil erosion amount, dust emission, and nutrient loss.

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 practical management solutions.

Wind erodibility of soils at Fort Irwin, California (Mojave Desert), USA, before and after trampling disturbance: Implications for land management

USGS Publications Warehouse

Belnap, J.; Phillips, S.L.; Herrick, J.E.; Johansen, J.R.

2007-01-01

Recently disturbed and 'control' (i.e. less recently disturbed) soils in the Mojave Desert were compared for their vulnerability to wind erosion, using a wind tunnel, before and after being experimentally trampled. Before trampling, control sites had greater cyanobacterial biomass, soil surface stability, threshold friction velocities (TFV, i.e. the wind speed required to move soil particles), and sediment yield than sites that had been more recently disturbed by military manoeuvres. After trampling, all sites showed a large drop in TFVs and a concomitant increase in sediment yield. Simple correlation analyses showed that the decline in TFVs and the rise in sediment yield were significantly related to cyanobacterial biomass (as indicated by soil chlorophyll a). However, chlorophyll a amounts were very low compared to chlorophyll a amounts found at cooler desert sites, where chlorophyll a is often the most important factor in determining TFV and sediment yield. Multiple regression analyses showed that other factors at Fort Irwin were more important than cyanobacterial biomass in determining the overall site susceptibility to wind erosion. These factors included soil texture (especially the fine, medium and coarse sand fractions), rock cover, and the inherent stability of the soil (as indicated by subsurface soil stability tests). Thus, our results indicate that there is a threshold of biomass below which cyanobacterial crusts are not the dominant factor in soil vulnerability to wind erosion. Most undisturbed soil surfaces in the Mojave Desert region produce very little sediment, but even moderate disturbance increases soil loss from these sites. Because current weathering rates and dust inputs are very low, soil formation rates are low as well. Therefore, soil loss in this region is likely to have long-term effects.

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...

Glyphosate and AMPA contents in sediments produced by wind erosion of agricultural soils in Argentina

NASA Astrophysics Data System (ADS)

Aparicio, Virginia; Aimar, Silvia; De Gerónimo, Eduardo; Buschiazzo, Daniel; Mendez, Mariano; Costa, José Luis

2014-05-01

Wind erosion of soils is an important event in arid and semiarid regions of Argentina. The magnitude of wind erosion occurring under different management practices is relatively well known in this region but less information is available on the quality of the eroded material. Considering that the intensification of agriculture may increase the concentrations of substances in the eroded material, producing potential negative effects on the environment, we analyzed the amount of glyphosate and AMPA in sediments produced by wind erosion of agricultural soils of Argentina. Wind eroded materials were collected by means of BSNE samplers in two loess sites of the semiarid region of Argentina: Chaco and La Pampa. Samples were collected from 1 ha square fields at 13.5, 50 and 150 cm height. Results showed that at higher heights the concentrations of glyphosate and AMPA were mostly higher. The glyphosate concentration was more variable and higher in Chaco (0.66 to 313 µg kg-1) than in La Pampa (4.17 to 114 µg kg-1). These results may be due to the higher use of herbicides in Chaco, where the predominant crops are soybeans and corn, produced under no-tillage. Under these conditions the use of glyphosate for weeds control is a common practice. Conversely, AMPA concentrations were higher in La Pampa (13.1 to 101.3 µg kg-1) than in Chaco (1.3 to 83 µg kg-1). These preliminary results show high concentrations of glyphosate and AMPA in wind eroded materials of agricultural soils of Argentina. More research is needed to confirm these high concentrations in other conditions in order to detect the temporal and spatial distribution patterns of the herbicide.

Wind erosion in semiarid landscapes: Predictive models and remote sensing methods for the influence of vegetation

NASA Technical Reports Server (NTRS)

Musick, H. Brad; Truman, C. Randall; Trujillo, Steven M.

1992-01-01

Wind erosion in semi-arid regions is a significant problem for which the sheltering effect of rangeland vegetation is poorly understood. Individual plants may be considered as porous roughness elements which absorb or redistribute the wind's momentum. The saltation threshold is the minimum wind velocity at which soil movement begins. The dependence of the saltation threshold on geometrical parameters of a uniform roughness array was studied in a wind tunnel. Both solid and porous elements were used to determine relationships between canopy structure and the threshold velocity for soil transport. The development of a predictive relation for the influence of vegetation canopy structure on wind erosion of soil is discussed.

The National Wind Erosion Research Network: Building a standardized long-term data resource for aeolian research, modeling and land management

USGS Publications Warehouse

Webb, Nicholas P.; Herrick, Jeffrey E.; Van Zee, Justin W; Courtright, Ericha M; Hugenholtz, Ted M; Zobeck, Ted M; Okin, Gregory S.; Barchyn, Thomas E; Billings, Benjamin J; Boyd, Robert A.; Clingan, Scott D; Cooper, Brad F; Duniway, Michael C.; Derner, Justin D.; Fox, Fred A; Havstad, Kris M.; Heilman, Philip; LaPlante, Valerie; Ludwig, Noel A; Metz, Loretta J; Nearing, Mark A; Norfleet, M Lee; Pierson, Frederick B; Sanderson, Matt A; Sharrat, Brenton S; Steiner, Jean L; Tatarko, John; Tedela, Negussie H; Todelo, David; Unnasch, Robert S; Van Pelt, R Scott; Wagner, Larry

2016-01-01

The National Wind Erosion Research Network was established in 2014 as a collaborative effort led by the United States Department of Agriculture’s Agricultural Research Service and Natural Resources Conservation Service, and the United States Department of the Interior’s Bureau of Land Management, to address the need for a long-term research program to meet critical challenges in wind erosion research and management in the United States. The Network has three aims: (1) provide data to support understanding of basic aeolian processes across land use types, land cover types, and management practices, (2) support development and application of models to assess wind erosion and dust emission and their impacts on human and environmental systems, and (3) encourage collaboration among the aeolian research community and resource managers for the transfer of wind erosion technologies. The Network currently consists of thirteen intensively instrumented sites providing measurements of aeolian sediment transport rates, meteorological conditions, and soil and vegetation properties that influence wind erosion. Network sites are located across rangelands, croplands, and deserts of the western US. In support of Network activities, http://winderosionnetwork.org was developed as a portal for information about the Network, providing site descriptions, measurement protocols, and data visualization tools to facilitate collaboration with scientists and managers interested in the Network and accessing Network products. The Network provides a mechanism for engaging national and international partners in a wind erosion research program that addresses the need for improved understanding and prediction of aeolian processes across complex and diverse land use types and management practices.

Radionuclides in Soils Along a Mountain-Basin Transect in the Koratepa Mountains of Uzbekistan

USDA-ARS?s Scientific Manuscript database

Wind tunnels have been used for several decades to study wind erosion processes. Portable wind tunnels offer the advantage of testing natural surfaces in the field, but they must be carefully designed to insure that a logarithmic boundary layer is formed and that wind erosion processes may develop ...

Using Rare Earth Elements (REE) to determine wind-driven soil dispersal from a point source

USDA-ARS?s Scientific Manuscript database

Although erosion of soil by water is a predictably directional process, the erosion of soil by wind is determined by wind direction on an event-wise basis. The wind-driven dispersal patterns of chemical constituents including natural soil components and anthropogenic contaminants are not well under...

The relevance of wind-driven rain for future soil erosion research

NASA Astrophysics Data System (ADS)

Fister, Wolfgang; Marzen, Miriam; Iserloh, Thomas; Seeger, Manuel; Heckrath, Goswin; Greenwood, Philip; Kuhn, Nikolaus J.; Ries, Johannes B.

2014-05-01

The influence of wind on falling raindrops and its potential to alter soil erosion rates was already proposed during the 1960s, but never really reached broad awareness in the soil erosion research community. Laboratory investigations over the last 15 years confirmed earlier findings and have proven that wind modifies the characteristics of falling raindrops in many ways. Most importantly, the impact angles and impact frequencies, as well as the drop velocities, drop sizes and hence the kinetic energy are modified. Consequently, the results of laboratory experiments on highly disturbed, loose, and mostly sandy substrates indicate that soil detachment and transport/splash distances of particles increase under the influence of wind. However, these experiments cannot reflect the complexity of naturally developed soils and a direct transfer of these findings to field conditions is therefore limited. So far, only a few field studies have reported increased erosion rates due to splash drift or increased runoff by wind-driven rain. Because of the lack of simultaneous reference measurements without the influence of wind, these studies were not able to discriminate between the different processes and thus couldn not clearly prove the relevance of wind-driven rainfall. Despite all these findings, the awareness of this phenomenon is, in our opinion, still limited. Almost all rainfall simulations exclude the factor of wind as a disturbance to reach more representative rainfall conditions on the plot. We think, that among other reasons, this underestimation of the influence of wind could be due to the absence of an adequate measurement device to simulate these processes and additionally, due to the fact that the relevance of wind-driven rain in a landscape context has not yet been proven. To overcome this lack of a useful device, and to take the research from the laboratory to the field on real soils again, the first portable wind and rainfall simulator was developed within this PhD-project. By measuring soil erosion rates on the same plot, both with and without wind application, the influence of wind on soil detachment and erosion rates can now clearly be determined. Field experiments with the Portable Wind and Rainfall Simulator, which were carried out in Andalusia (Spain), in Wageningen (The Netherlands), and in Foulum (Denmark) during and within 3 years after finishing the PhD-project, aimed to improve the knowledge of processes involved, and to show the relevance of wind-driven rainfall erosion. The results indicate that the influence of wind depends on the complexity of the landscape. In an environment with homogenous conditions (loose sand mixture) and only a few variable factors (i.e. no vegetation, no surface roughness, no slope), like the test site in Wageningen, the increase of erosion rates due to the influence of wind could be seen in almost every test run. This clear influence of wind decreased with the amount of involved factors from agricultural soils in Denmark with a homogenous sandy texture and steep slopes, to highly degraded abandoned/fallow land with thick soil crusts and a clay-silt texture in Andalusia. The results obtained by "simple" rainfall simulations, therefore, clearly underestimate soil erosion rates, depending on the environment. This could, in our opinion, have strong implications for future soil erosion research and modelling.

RUSLE2015, GIS-RWEQ and CENTURY: new modelling integration for soil loss and carbon fluxes at European scale

NASA Astrophysics Data System (ADS)

Panagos, Panos; Borrelli, Pasquale; Lugato, Emanuele

2016-04-01

Land degradation through erosion has been identified as major threat to European soils and agriculture. During the last years, the Directorates General for Agriculture and for Environment (plus EUROSTAT) require formal assessments and indicators on the state of soil erosion for the European Union. Moreover, the European Soil Data Centre (ESDAC) is the main data repository for soil threats at European scale. To meet these needs we have worked with recognized research institutes and scientists to develop a series of pan-EU modelling tools that estimate soil erosion by water and wind. Over the past three years, the European Commission Joint Research Centre has worked to develop a modified RUSLE modelling approach, named RUSLE2015 and the necessary input factors. These have all been peer reviewed and published as individual papers in different refereed journals. The published soil erodibility map for Europe has been modelled with the latest state of the art soil data (LUCAS) and a robust geo-statistical model (Science of Total Environment, 479-480: 189-200). Rainfall erosivity has been modelled after an extensive data collection of high temporal resolution rainfall data and the compilation of Rainfall Erosivity Database at European Scale (REDES) (Science of Total Environment, 511: 801-814). Cover-Management factor has been modelled taking into account crop composition, management practices (reduced tillage, plant residues, cover crops) and remote sensing data on vegetation density (Land Use policy, 48C: 38-50). Topography has been modelled with the recently published Digital Elevation Model at 25m resolution (Geosciences, 5: 117-126). Conservation and support practices have included the Good Agricultural Environmental Condition (GAEC database) and the 270,000 earth observations of LUCAS survey (Environmental Science & Policy 51: 23-34). The new assessment of soil erosion by water in Europe has been recently published (Environmental Science & Policy. 54: 438-447) and subsequently the core message focusing on soil erosion in agricultural lands was published in a recent correspondence in Nature (Nature, 526, 195). Additionally, the soil erosion potential for the European Union's forests was modelled using the high-resolution Global Forest Cover Loss map (2000-2012) and taking into consideration the lodging, forest cuts and forest fires (Ecological Indicators, 60:1208-1220). The first qualitative assessment of wind erosion at European scale has been done using the Index of Land Susceptibility to Wind Erosion (ILSWE) (Sustainability, 7(7): 8823-8836). The wind-erodible fraction of soil (EF) is one of the key parameters for estimating the susceptibility of soil to wind erosion (Geoderma, 232-234: 471-478). ILSWE was created by combining spatiotemporal variations of the most influential wind erosion factors such as climatic erosivity, soil erodibility, vegetation cover and landscape roughness) (Land Degradation & Development, 10.1002/ldr.2318). The quantitative assessment of wind erosion has been concluded recently using Revised Wind Erosion Equation (GIS-RWEQ). Modelling the lateral carbon fluxes due to soil erosion both at national scale (Land Use Policy, 50: 408-421) and at European scale (Global Change Biology, 10.1111/gcb.13198) is an important milestone in climate change perspective. We coupled soil erosion into a biogeochemistry model, running at 1 km2 resolution across the agricultural soils of the European Union (EU). In the future, the soil erosion (by water and wind) modelling activities will incorporate temporal variability, sediment transport and economic assessments of land degradation.

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 Ltd. All rights reserved.

Short-term soil loss by eolian erosion in response to different rain-fed agricultural practices

NASA Astrophysics Data System (ADS)

Tanner, Smadar; Katra, Itzhak; Zaady, Eli

2016-04-01

Eolian (wind) erosion is a widespread process and a major form of soil degradation in arid and semi-arid regions. The present study examined changes in soil properties and eolian soil loss at a field scale in response to different soil treatments in two rain-fed agricultural practices. Field experiments with a boundary-layer wind tunnel and soil analysis were used to obtain the data. Two practices with different soil treatments (after harvest), mechanical tillage and stubble grazing intensities, were applied in the fallow phase of the rotation (dry season). The mechanical tillage and the stubble grazing had an immediate and direct effects on soil aggregation but not on the soil texture, and the contents of soil water, organic matter, and CaCO3. Higher erosion rates, that was measured as fluxes of total eolian sediment and particulate matter <10 μm (PM10), were recorded under mechanical tillage and grazing intensities compared with the undisturbed topsoil of the control plots. The erosion rates were higher in grazing plots than in tillage plots. The calculated soil fluxes in this study indicate potentially rapid soil degradation due to loss of fine particles by wind. The finding may have implications for long-term management of agricultural soils in semi-arid areas.

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

NASA Astrophysics Data System (ADS)

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

2015-12-01

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

Application of a modeling approach to designate soil and soil organic carbon loss to wind erosion on long-term monitoring sites (BDF) in Northern Germany

NASA Astrophysics Data System (ADS)

Nerger, Rainer; Funk, Roger; Cordsen, Eckhard; Fohrer, Nicola

2017-04-01

Soil organic carbon (SOC) loss is a serious problem in maize monoculture areas of Northern Germany. Sites of the soil monitoring network (SMN) "Boden-Dauerbeobachtung" show long-term soil and SOC losses, which cannot be explained by conventional SOC balances nor by other non-Aeolian causes. Using a process-based model, the main objective was to determine whether these losses can be explained by wind erosion. In the long-term context of 10 years, wind erosion was not measured directly but often observed. A suitable estimation approach linked high-quality soil/farming monitoring data with wind erosion modeling results. The model SWEEP, validated for German sandy soils, was selected using 10-minute wind speed data. Two similar local SMN study sites were compared, however, site A was characterized by high SOC loss and often affected by wind erosion, while the reference site B was not. At site A soil mass and SOC stock decreased by 49.4 and 2.44 kg m-2 from 1999 to 2009. Using SWEEP, a total soil loss of 48.9 kg m-2 resulted for 16 erosion events (max. single event 12.6 kg m-2). A share of 78% was transported by suspension with a SOC enrichment ratio (ER) of 2.96 (saltation ER 0.98), comparable to the literature. At the reference site measured and modeled topsoil losses were minimal. The good agreement between monitoring and modeling results suggested that wind erosion caused significant long-term soil and SOC losses. The approach uses results of prior studies and is applicable to similar well-studied sites without other noteworthy SOC losses.

Using Crater Counts to Constrain Erosion Rates on Mars: Implications for the Global Dust Cycle, Sedimentary Rock Erosion and Organic Matter Preservation

NASA Astrophysics Data System (ADS)

Mayer, D. P.; Kite, E. S.

2016-12-01

Sandblasting, aeolian infilling, and wind deflation all obliterate impact craters on Mars, complicating the use of crater counts for chronology, particularly on sedimentary rock surfaces. However, crater counts on sedimentary rocks can be exploited to constrain wind erosion rates. Relatively small, shallow craters are preferentially obliterated as a landscape undergoes erosion, so the size-frequency distribution of impact craters in a landscape undergoing steady exhumation will develop a shallower power-law slope than a simple production function. Estimating erosion rates is important for several reasons: (1) Wind erosion is a source of mass for the global dust cycle, so the global dust reservoir will disproportionately sample fast-eroding regions; (2) The pace and pattern of recent wind erosion is a sorely-needed constraint on models of the sculpting of Mars' sedimentary-rock mounds; (3) Near-surface complex organic matter on Mars is destroyed by radiation in <108 years, so high rates of surface exhumation are required for preservation of near-surface organic matter. We use crater counts from 18 HiRISE images over sedimentary rock deposits as the basis for estimating erosion rates. Each image was counted by ≥3 analysts and only features agreed on by ≥2 analysts were included in the erosion rate estimation. Erosion rates range from 0.1-0.2 {μ }m/yr across all images. These rates represent an upper limit on surface erosion by landscape lowering. At the conference we will discuss the within and between-image variability of erosion rates and their implications for recent geological processes on Mars.

Crop production and economic loss due to wind erosion in hot arid ecosystem of India

NASA Astrophysics Data System (ADS)

Santra, Priyabrata; Moharana, P. C.; Kumar, Mahesh; Soni, M. L.; Pandey, C. B.; Chaudhari, S. K.; Sikka, A. K.

2017-10-01

Wind erosion is a severe land degradation process in hot arid western India and affects the agricultural production system. It affects crop yield directly by damaging the crops through abrasion, burial, dust deposition etc. and indirectly by reducing soil fertility. In this study, an attempt was made to quantify the indirect impact of wind erosion process on crop production loss and associated economic loss in hot arid ecosystem of India. It has been observed that soil loss due to wind erosion varies from minimum 1.3 t ha-1 to maximum 83.3 t ha-1 as per the severity. Yield loss due to wind erosion was found maximum for groundnut (Arachis hypogea) (5-331 kg ha-1 yr-1), whereas minimum for moth bean (Vigna aconitifolia) (1-93 kg ha-1 yr-1). For pearl millet (Pennisetum glaucum), which covers a major portion of arable lands in western Rajasthan, the yield loss was found 3-195 kg ha-1 yr-1. Economic loss was found higher for groundnut and clusterbean (Cyamopsis tetragonoloba) than rest crops, which are about

Effects of low-scale landscape structures on aeolian transport processes on arable land

NASA Astrophysics Data System (ADS)

Siegmund, Nicole; Funk, Roger; Koszinsky, Sylvia; Buschiazzo, Daniel Eduardo; Sommer, Michael

2018-06-01

The landscape of the semiarid Pampa in central Argentina is characterized by late Pleistocene aeolian deposits, covering large plains with sporadic dune structures. Since the current land use changed from extensive livestock production within the Caldenal forest ecosystem to arable land, the wind erosion risk increased distinctly. We measured wind erosion and deposition patterns at the plot scale and investigated the spatial variability of the erosion processes. The wind-induced mass-transport was measured with 18 Modified Wilson and Cooke samplers (MWAC), installed on a 1.44 ha large field in a 20 × 40 m grid. Physical and chemical soil properties from the upper soil as well as a digital elevation model were recorded in a 20 × 20 m grid. In a 5-month measuring campaign data from seven storms with three different wind directions was obtained. Results show very heterogeneous patterns of erosion and deposition for each storm and indicate favoured erosion on windward and deposits on leeward terrain positions. Furthermore, a multiple regression model was build, explaining up to 70% of the spatial variance of erosion by just using four predictors: topsoil thickness, relative elevation, soil organic carbon content and slope direction. Our findings suggest a structure-process-structure complex where the landscape structure determines the effects of recent wind erosion processes which again slowly influence the structure, leading to a gradual increase of soil heterogeneity.

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...

Spatial application of WEPS for estimating wind erosion in the Pacific Northwest

USDA-ARS?s Scientific Manuscript database

The Wind Erosion Prediction System (WEPS) is used to simulate soil erosion on croplands and was originally designed to run field scale simulations. This research is an extension of the WEPS model to run on multiple fields (grids) covering a larger region. We modified the WEPS source code to allow it...

Spatial application of WEPS for estimating wind erosion in the Pacific Northwest

USDA-ARS?s Scientific Manuscript database

The Wind Erosion Prediction System (WEPS) is used to simulate soil erosion on cropland and was originally designed to run simulations on a field-scale size. This study extended WEPS to run on multiple fields (grids) independently to cover a large region and to conduct an initial investigation to ass...

Multiple nuclide cosmogenic dating of very old desert pavements on the Puna Plateau, Northwest Argentina

NASA Astrophysics Data System (ADS)

Dortch, J.; Schoenbohm, L. M.

2011-12-01

Wind erosion of bedrock has been suggested to be responsible for the removal of more than 800 m of strata in the Qaidam Basin while wind deposition creates large-scale landforms such as the loess plateau. Wind eroded landforms, such as desert pavements in the Namibian Desert, Africa, form relic landscapes that are stable for more than 5 Ma. Desert pavements are of particular importance because of their widespread occurrence on terraces and fans, in mountains and coastal areas, and in hot and cold deserts including: Southwestern Africa, Antartic Dry valleys, Southwest USA, Denmark, Ireland, Israel, Sweden, and Central Tibet. Moreover, greater than 95 % of ventifacts on desert pavements are suspected to be late Quaternary to Holocene in age and are located on surfaces suitable for cosmogenic radionuclide dating. In spite of this, glacial, fluvial, and mass wasting systems have received far more attention than wind as an important geomorphic agent of erosion, deposition, and rock mass redistribution. Our goal is to: 1) quantify bedrock wind erosion rates; 2) quantify the ages of old, stable desert pavements; 3) and to identify which lithology-isotope pair provides the most accurate exposure ages for desert pavements in arid landscapes. The Puna Plateau, Argentina, is an ideal area to undertake this study because numerous wind eroded/deposited landforms are present, rates of fluvial erosion are low, and glaciation is limited. Mapping using remote sensed images shows that a significant portion of the Puna Plateau surface is covered by wind eroded or wind deposited landforms. These landforms align with the dominant wind direction (southeast) determined from ~450 ventifact measurements from 9 locations on the plateau. Twelve amalgamated samples sets that span six lithologies (granite, gneiss, quartzite, rhyolite, diabase, and basalt) using four cosmogenic isotopes (10Be, 26Al, 36Cl, 3He) on ventifacted clasts were collected from two surfaces to identify the most appropriate lithologies and cosmogenic isotopes for obtaining an accurate chronology of desert pavements. Moreover, 3He dating of six in situ samples from basalt flows with independent 39Ar/40Ar ages will begin to address long-term time-averaged wind erosion rates of bedrock while enabling wind-erosion rate corrections for pavement ventifacts. Our results and methodology can be applied worldwide and will aid future research in the many environments where ventifacts and/or high wind erosion rates are found.

Microbiology of Wind-eroded Sediments: Current Knowledge and Future Research Directions

USDA-ARS?s Scientific Manuscript database

Wind erosion is a threat to the sustainability and productivity of soils that takes place at local, regional, and global scales. Current estimates of cost of wind erosion have not included the costs associated with the loss of soil biodiversity and reduced ecosystem functions. Microorganisms carrie...

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...

Fugitive dust emissions from off-road vehicle maneuvers on military training lands

USDA-ARS?s Scientific Manuscript database

Off-road vehicle training can contribute to air quality degradation because of increased wind erosion as a result of soil disruption during high wind events. However, limited information exists regarding the impacts of off-road vehicle maneuvering on wind erosion potential of soils. This study was c...

Dust and nutrient enrichment by wind erosion from Danish soils in dependence of tillage direction

NASA Astrophysics Data System (ADS)

Mohammadian Behbahani, Ali; Fister, Wolfgang; Heckrath, Goswin; Kuhn, Nikolaus J.

2016-04-01

Wind erosion is a selective process, which promotes erosion of fine particles. Therefore, it can be assumed that increasing erosion rates are generally associated with increasing loss of dust sized particles and nutrients. However, this selective process is strongly affected by the orientation and respective trapping efficiency of tillage ridges and furrows. Since tillage ridges are often the only protection measure available on poorly aggregated soils in absence of a protective vegetation cover, it is very important to know which orientation respective to the dominant wind direction provides best protection. This knowledge could be very helpful for planning erosion protection measures on fields with high wind erosion susceptibility. The main objective of this study, therefore, was to determine the effect of tillage direction on dust and nutrient mobilization by wind, using wind tunnel simulations. In order to assess the relationship between the enrichment ratio of specific particle sizes and the amount of eroded nutrients, three soils with loamy sand texture, but varying amounts of sand-sized particles, were selected. In addition, a soil with slightly less sand, but much higher organic matter content was chosen. The soils were tested with three different soil surface scenarios - flat surface, parallel tillage, perpendicular tillage. The parallel tillage operation experienced the greatest erosion rates, independent of soil type. Particles with D50 between 100-155 μm showed the greatest risk of erosion. However, due to a greater loss of dust sized particles from perpendicularly tilled surfaces, this wind-surface arrangement showed a significant increase in nutrient enrichment ratio compared to parallel tillage and flat surfaces. The main reason for this phenomenon is most probably the trapping of larger particles in the perpendicular furrows. This indicates that the highest rate of soil protection does not necessarily coincide with lowest soil nutrient losses and dust emissions. For the evaluation of protection measures on these soil types in Denmark it is, therefore, important to differentiate between their effectivity to reduce total soil erosion amount, dust emission, and nutrient loss.

Implications of climate change on wind erosion of agricultural lands in the Columbia Plateau

USDA-ARS?s Scientific Manuscript database

Climate change may impact soil health and productivity as a result of accelerated or decelerated rates of erosion. Previous studies suggest a greater risk of wind erosion on arid and semi-arid lands due to loss of biomass under a future warmer climate. There have been no studies conducted to assess ...

Interactive Effects of Moss-Dominated Crusts and Artemisia ordosica on Wind Erosion and Soil Moisture in Mu Us Sandland, China

PubMed Central

Yang, Yongsheng; Bu, Chongfeng; Mu, Xingmin; Shao, Hongbo; Zhang, Kankan

2014-01-01

To better understand the effects of biological soil crusts (BSCs) on soil moisture and wind erosion and study the necessity and feasibility of disturbance of BSCs in the Mu Us sandland, the effects of four treatments, including moss-dominated crusts alone, Artemisia ordosica alone, bare sand, and Artemisia ordosica combined with moss-dominated crusts, on rainwater infiltration, soil moisture, and annual wind erosion were observed. The major results are as follows. (1) The development of moss-dominated crusts exacerbated soil moisture consumption and had negative effects on soil moisture in the Mu Us sandland. (2) Moss-dominated crusts significantly increased soil resistance to wind erosion, and when combined with Artemisia ordosica, this effect became more significant. The contribution of moss-dominated crusts under Artemisia ordosica was significantly lower than that of moss-dominated crusts alone in sites where vegetative coverage > 50%. (3) Finally, an appropriate disturbance of moss-dominated crusts in the rainy season in sites with high vegetative coverage improved soil water environment and vegetation succession, but disturbance in sites with little or no vegetative cover should be prohibited to avoid the exacerbation of wind erosion. PMID:24982973

Interactive effects of moss-dominated crusts and Artemisia ordosica on wind erosion and soil moisture in Mu Us sandland, China.

PubMed

Yang, Yongsheng; Bu, Chongfeng; Mu, Xingmin; Shao, Hongbo; Zhang, Kankan

2014-01-01

To better understand the effects of biological soil crusts (BSCs) on soil moisture and wind erosion and study the necessity and feasibility of disturbance of BSCs in the Mu Us sandland, the effects of four treatments, including moss-dominated crusts alone, Artemisia ordosica alone, bare sand, and Artemisia ordosica combined with moss-dominated crusts, on rainwater infiltration, soil moisture, and annual wind erosion were observed. The major results are as follows. (1) The development of moss-dominated crusts exacerbated soil moisture consumption and had negative effects on soil moisture in the Mu Us sandland. (2) Moss-dominated crusts significantly increased soil resistance to wind erosion, and when combined with Artemisia ordosica, this effect became more significant. The contribution of moss-dominated crusts under Artemisia ordosica was significantly lower than that of moss-dominated crusts alone in sites where vegetative coverage > 50%. (3) Finally, an appropriate disturbance of moss-dominated crusts in the rainy season in sites with high vegetative coverage improved soil water environment and vegetation succession, but disturbance in sites with little or no vegetative cover should be prohibited to avoid the exacerbation of wind erosion.

The National Wind Erosion Research Network: Building a standardized long-term data resource for aeolian research, modeling and land management

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 a broad and coordinated research program to develop wind ...

Wind erosion of waste impoundments in arid climates and mitigation of dust pollution.

PubMed

Blight, G E

2008-12-01

Wind can erode and disperse fine-grained material from an impoundment of mining, industrial or municipal waste that stands above the level of its surroundings. Such dust dispersion can be a serious nuisance as well as a health hazard to inhabitants and animals in nearby settlements. It can also degrade crops, making them less marketable, and pollute soil, surface water and ground water. Wind can seasonally erode waste impoundments in all types of climate, but the erosion intensifies and persists for more of each year as regional aridity increases. As clouds of dust are often observed billowing across the top surfaces of waste impoundments in dry windy weather, there is a common misconception that dust arises from erosion of the top surface of an impoundment, resulting in much effort and money being misspent on top treatments when in fact the sloped sides of the impoundments are the true source of blown dust. This paper offers a brief review of general waste impoundment wind erosion issues and then focuses in more detail on the mechanics of how wind erodes surfaces of waste impoundments. Recommendations are offered for mitigating the effects of wind-eroded dust.

Soil nutrients losses by wind erosion in a citrus crop at southeast Spain

NASA Astrophysics Data System (ADS)

Segovia, C.; Gómez, J. D.; Gallardo, P.; Lozano, F. J.; Asensio, C.

2017-06-01

The purpose of this study was to analyze the influence of wind erosion on the productivity of citric crops over gypsiric Fluvisols in Gador area (Almeria, SE Spain) by blowing air through a wind tunnel. Wind erosion varies considerably depending on time since the last tillage. This is because a physical crust forms after tilling which protects the soil from wind. Crust formation in the study area is strongly favored by dew, which causes them to form in around a week. The repeated measurements ANOVA, as a nonparametric alternative to the ANOVA, using the Geiiser method and the Friedman test shows significant differences ( P ≤ 0.05) in the fractions of very fine sand and coarse silt, which confirmed that very fine sand and coarse silt are the fractions most susceptible to loss from wind. The same statistical analysis for fertility showed smaller differences in organic carbon and K2O content, while N and P2O5 increased. Nutrients lost from wind imply an additional fertilization cost for a crop to be economically feasible. The cost of this restoration of nutrients lost from the soil because of wind erosion was based on experimental data taken in crusted soil and immediately after tilling. Losses in organic matter (O.M.), N, P2O5 and K2O were estimated based on the cost of fertilizers most commonly used in the area.

Wind driven erosion and the effects of particulate electrification

NASA Astrophysics Data System (ADS)

Merrison, J. P.; Bak, E.; Finster, K.; Gunnlaugsson, H. P.; Holstein-Rathlou, C.; Knak Jensen, S.; Nørnberg, P.; Rasmussen, K. R.

2012-09-01

Several related aspects of Aeolian activity are presently being studied in the laboratory, the most recent advances in this field will be presented. These include simulating wind driven erosion in the laboratory, quantifying erosion rates and the study of mineral change due to mechanical activation. Also advances in our understanding of the electrification of sand/dust particles is being made and how this phenomenon affects their behavior.

Vegetation in drylands: Effects on wind flow and aeolian sediment transport

USDA-ARS?s Scientific Manuscript database

Drylands are characterised by patchy vegetation, erodible surfaces and erosive aeolian processes. Empirical and modelling studies have shown that vegetation elements provide drag on the overlying airflow, thus affecting wind velocity profiles and altering erosive dynamics on desert surfaces. However...

MULTI-SCALE CONTROLS ON AND CONSEQUENCES OF AEOLIAN PROCESSES IN LANDSCAPE CHANGE IN ARID AND SEMI-ARID ENVIRONMENTS

EPA Science Inventory

This paper reviews the controls on aeolian processes and their consequences at plant-interspace, patch-landscape, and regional-global scales. Based on this review, we define the requirements for a cross-scale model of wind erosion in structurally complex arid and semiarid ecosyst...

Enhancing wind erosion monitoring and assessment for US rangelands

USDA-ARS?s Scientific Manuscript database

Wind erosion is a major resource concern for rangeland managers because it can impact soil health, ecosystem structure and function, hydrologic processes, agricultural production and air quality. Despite its significance, little is known about which landscapes are eroding, by how much, and when. T...

The effect of vegetation patterns on wind-blown mass transport at the regional scale: A wind tunnel experiment

NASA Astrophysics Data System (ADS)

Youssef, Feras; Visser, Saskia M.; Karssenberg, Derek; Erpul, Gunay; Cornelis, Wim M.; Gabriels, Donald; Poortinga, Ate

2012-07-01

Wind erosion is a global environmental problem. Re-vegetating land is a commonly used method to reduce the negative effects of wind erosion. However, there is limited knowledge on the effect of vegetation pattern on wind-blown mass transport. The objective of this study was to investigate the effect of vegetation pattern on this phenomenon within a land unit and at the border between land units. Wind tunnel experiments were conducted with artificial shrubs representing Atriplex halimus. Wind runs at a speed of 11 m s- 1 were conducted and sand translocation was measured after 200-230 s using a graph paper prepared for this purpose. This research showed that: 1) the transport within a land unit is affected by the neighboring land units and by the vegetation pattern within both the unit itself and the neighboring land units; 2) re-vegetation plans for degraded land can take into account the 'streets' effect (zones of erosion areas similar to streets); 3) the effect of neighboring land units includes sheltering effect and the regulation of sediment passing from one land unit to the neighboring land units and 4) in addition to investigation of the general effect of vegetation pattern on erosion and deposition within the region, it is important to investigate the redistribution of sediment at smaller scales depending on the scope of the project.

Crater Mound Formation by Wind Erosion on Mars

NASA Astrophysics Data System (ADS)

Steele, L. J.; Kite, E. S.; Michaels, T. I.

2018-01-01

Most of Mars' ancient sedimentary rocks by volume are in wind-eroded sedimentary mounds within impact craters and canyons, but the connections between mound form and wind erosion are unclear. We perform mesoscale simulations of different crater and mound morphologies to understand the formation of sedimentary mounds. As crater depth increases, slope winds produce increased erosion near the base of the crater wall, forming mounds. Peak erosion rates occur when the crater depth is ˜2 km. Mound evolution depends on the size of the host crater. In smaller craters mounds preferentially erode at the top, becoming more squat, while in larger craters mounds become steeper sided. This agrees with observations where smaller craters tend to have proportionally shorter mounds and larger craters have mounds encircled by moats. If a large-scale sedimentary layer blankets a crater, then as the layer recedes across the crater it will erode more toward the edges of the crater, resulting in a crescent-shaped moat. When a 160 km diameter mound-hosting crater is subject to a prevailing wind, the surface wind stress is stronger on the leeward side than on the windward side. This results in the center of the mound appearing to "march upwind" over time and forming a "bat-wing" shape, as is observed for Mount Sharp in Gale crater.

Characterization of microbes carried in dust

USDA-ARS?s Scientific Manuscript database

There is still a lack of understanding of how soil microbial community distribution is controlled by wind erosion. This information is of international concern as eroded sediments can potentially carry away the active labile organic soil particulates containing key microorganisms involved in soil bi...

23 CFR 650.205 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-04-01

..., STRUCTURES, AND HYDRAULICS Erosion and Sediment Control on Highway Construction Projects § 650.205... transporting of soil particles by water or wind, including actions that limit the area of exposed soil and... completion of the project. Pollutants are substances, including sediment, which cause deterioration of water...

23 CFR 650.205 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-04-01

..., STRUCTURES, AND HYDRAULICS Erosion and Sediment Control on Highway Construction Projects § 650.205... transporting of soil particles by water or wind, including actions that limit the area of exposed soil and... completion of the project. Pollutants are substances, including sediment, which cause deterioration of water...

23 CFR 650.205 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-04-01

..., STRUCTURES, AND HYDRAULICS Erosion and Sediment Control on Highway Construction Projects § 650.205... transporting of soil particles by water or wind, including actions that limit the area of exposed soil and... completion of the project. Pollutants are substances, including sediment, which cause deterioration of water...

23 CFR 650.205 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-04-01

..., STRUCTURES, AND HYDRAULICS Erosion and Sediment Control on Highway Construction Projects § 650.205... transporting of soil particles by water or wind, including actions that limit the area of exposed soil and... completion of the project. Pollutants are substances, including sediment, which cause deterioration of water...

23 CFR 650.205 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-04-01

..., STRUCTURES, AND HYDRAULICS Erosion and Sediment Control on Highway Construction Projects § 650.205... transporting of soil particles by water or wind, including actions that limit the area of exposed soil and... completion of the project. Pollutants are substances, including sediment, which cause deterioration of water...

On the geoethical implications of wind erosion

NASA Astrophysics Data System (ADS)

Károly, Tatárvári

2016-04-01

Human activities exerts an ever growing impact on our environment, and this is undeniably the responsibility of mankind. In spite of this fact there is almost no process in our environment that can be described exactly with complete exactness, and the working of which is known in full extent. Wind erosion is such a process. Although water erosion is mentioned ever more often in scientific circles as a from of erosion, its effect is restrained to a certain region, although it may cause perceptibly damage of a greater extent in short time. Wind erosion, apart from the fact that it may have global impact, may play an important role in the warming of our climate according to recent studies. First of all, wind erosion may cause damage far from its origin in human health, nutrition, or in the environment in general. Today several surveys have proved, that erosion caused by wind significantly contributes to the air pollution of cities, the fine dust carried as drift by the wind may cause severe environmental damage in accumulation zones. Microbes, toxic material may attach themselves to the dust carried this way and carried on and by the wings of the wind they may cause health issues in humans animals and plants as well. In spite of these facts there are almost no measures against wind erosion employed in arable land, although our ever doughtier climate and changes would make these necessary. Reduction of organic matter content presents a great problem in a large part of cultivated land, so the risk of the production of high quality food raises questions of more and more ethical nature. Who is responsible? The fact, that the chemicals used in a growing extent by agriculture may reach many people causing considerable damage to the environment also raises serious ethical questions. More and more periods with extreme weather conditions are experienced in Hungary and Europe as the effect of climate change. Drought periods are longer and more frequent as the intensity of precipitation changes, this also increases the occurrence of bush-fires, and the growing extent of uncovered soil surface shall intensify wind erosion as well accelerating the negative effects described above. Who will be held responsible for this? Who should bear the larger cost of production in agriculture that is caused by the cost of research necessary to uncover the methods of prevention of irreversible damages caused in nature and environment? Because the field of research requires an interdisciplinary approach, research and innovation requires huge funds, the different approaches to the problem in every single field, and different reasoning methods represent a hurdle as well. In search for possible solutions it is necessary that political decision-makers adopt regulations which have solid scientific fundamentals, and also the cooperation of mankind active in science and economy is crucial. This is the only way of finding sustainable and long term solutions to the problem.

Applications of WEPS and SWEEP to non-agricultural lands

USDA-ARS?s Scientific Manuscript database

Soil erosion by wind is a serious problem on agricultural lands throughout the United States and the world. Dust from wind erosion obscures visibility and pollutes the air. It fills road ditches where it can impact water quality, causes automobile accidents, fouls machinery, and imperils animal an...

WebStart WEPS: Remote data access and model execution functionality added to WEPS

USDA-ARS?s Scientific Manuscript database

The Wind Erosion Prediction System (WEPS) is a daily time step, process based wind erosion model developed by the United States Department of Agriculture - Agricultural Research Service (USDA-ARS). WEPS simulates climate and management driven changes to the surface/vegetation/soil state on a daily b...

Use of Anthropogenic Radioisotopes to Estimate Rates of Soil Redistribution by Wind

USDA-ARS?s Scientific Manuscript database

Wind erosion results in soil degradation and fugitive dust emissions. The temporal and spatial variability of aeolian processes makes local estimates of long-term average erosion costly and time consuming. Atmospheric testing of nuclear weapons during the 1950s and 1960s resulted in previously non...

DEVELOPMENT OF COUNTY-LEVEL WIND EROSION AND UNPAVED ROAD ALKALINE EMISSION ESTIMATES FOR THE 1985 NAPAP EMISSIONS INVENTORY

EPA Science Inventory

The report details the methods used and the result of the conversion of the National Acid Precipitation Assessment Program's (NAPAP's) alkaline material emissions information for wind erosion, unpaved roads, and dust devils from the' current spatial resolution to county-level res...

Using shadow to reformulate wind erosion modelling, mapping and monitoring

USDA-ARS?s Scientific Manuscript database

Wind erosion and dust emission models are required to assess the impacts of dust in the Earth system. We describe a need in aeolian research to adequately represent the spatial variability and particularly the area average of the key aerodynamic properties which influence these models and our unders...

Soil characteristics and wind erosion potential of wheat-oilseed-fallow cropping systems

USDA-ARS?s Scientific Manuscript database

Oilseeds are integral to the production of biofuels and diversifying rainfed cropping systems in the Pacific Northwest United States (PNW). However, there is evidence to suggest greater potential for wind erosion when growing oilseeds in wheat rotations. Little is known concerning the impact of grow...

Standing crop residues and wind erosion

USDA-ARS?s Scientific Manuscript database

Wind erosion and blinding dust storms in the Central Great Plains region still occasionally erupt. Eliminating all tillage remains the best remedy. However, farmers in the region somehow fail to remember the lessons learned in the “dirty 30’s”. They forget how devastating tillage is in disrupting t...

Application of the WEPS and SWEEP models to non-agricultural disturbed lands

USDA-ARS?s Scientific Manuscript database

Wind erosion not only affects agricultural productivity but also soil, air, and water quality. Dust and specifically particulate matter = 10 µm (PM-10) has adverse effects on respiratory health and also reduces visibility along roadways, resulting in auto accidents. The Wind Erosion Prediction Syste...

Aeolian processes over gravel beds: Field wind tunnel simulation and its application atop the Mogao Grottoes, China

NASA Astrophysics Data System (ADS)

Zhang, Weimin; Tan, Lihai; Zhang, Guobin; Qiu, Fei; Zhan, Hongtao

2014-12-01

The aeolian processes of erosion, transport and deposition are threatening the Mogao Grottoes, a world culture heritage site. A field wind tunnel experiment was conducted atop the Mogao Grottoes using weighing sensors to quantify aeolian processes over protective gravel beds. Results reveal that aeolian erosion and deposition over gravel beds are basically influenced by gravel coverage and wind speed. Erosion is a main aeolian process over gravel beds and its strength level is mainly determined by gravel coverage: strong (<30%), medium (30-50%) and slight (>50%). Aeolian deposition only occurs when gravel coverage is equal to or greater than 30% and wind speeds are between 8 and 12 m s-1, and this process continues until the occurrence of the equilibrium coverage. In addition, the change in conditions of external sand supply affects the transition between aeolian deposition and erosion over gravel beds, and the quantity of sand transport at the height of 0-24 mm is an important indicator of aeolian deposition and erosion over gravel beds. Our results also demonstrate that making the best use of wind regime atop the Mogao Grottoes and constructing an artificial gobi surface in staggered arrays, with 30% coverage and 30-mm-high gravels and in 40 mm spacing can trap westerly invading sand flow and enable the stronger easterly wind to return the deposited sand on the gravel surface back to the Mingsha Mountain so as to minimize the damage of the blown sand flux to the Mogao Grottoes.

Wind tunnel simulation of Martian sand storms

NASA Technical Reports Server (NTRS)

Greeley, R.

1980-01-01

The physics and geological relationships of particles driven by the wind under near Martian conditions were examined in the Martian Surface Wind Tunnel. Emphasis was placed on aeolian activity as a planetary process. Threshold speeds, rates of erosion, trajectories of windblown particles, and flow fields over various landforms were among the factors considered. Results of experiments on particles thresholds, rates of erosion, and the effects of electrostatics on particles in the aeolian environment are presented.

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%.

Dust emission and soil loss due to anthropogenic activities by wind erosion simulations

NASA Astrophysics Data System (ADS)

Katra, Itzhak; Swet, Nitzan; Tanner, Smadar

2017-04-01

Wind erosion is major process of soil loss and air pollution by dust emission of clays, nutrients, and microorganisms. Many soils throughout the world are currently or potentially associated with dust emissions, especially in dryland zones. The research focuses on wind erosion in semi-arid soils (Northern Negev, Israel) that are subjected to increased human activities of urban development and agriculture. A boundary-layer wind tunnel has been used to study dust emission and soil loss by simulation and quantification of high-resolution wind processes. Field experiments were conducted in various surface types of dry loess soils. The experimental plots represent soils with long-term and short term influences of land uses such as agriculture (conventional and organic practices), grazing, and natural preserves. The wind tunnel was operated under various wind velocities that are above the threshold velocity of aeolian erosion. Total soil sediment and particulate matter (PM) fluxes were calculated. Topsoil samples from the experimental plots were analysed in the laboratory for physical and chemical characteristics including aggregation, organic matter, and high-resolution particle size distribution. The results showed variations in dust emission in response to surface types and winds to provide quantitative estimates of soil loss over time. Substantial loss of particulate matter that is < 10 micrometer in diameter, including clays and nutrients, was recorded in most experimental conditions. Integrative analyses of the topsoil properties and dust experiment highlight the significant implications for soil nutrient resources and management strategies as well as for PM loading to the atmosphere and air pollution.

Erodibility of and dust emissions from bare soil surfaces in the North American Southwest

USDA-ARS?s Scientific Manuscript database

Native plant communities throughout the Southwestern United States are subject to increased abiotic stress due to climate change. As native grass cover is replaced by shrubs, more bare soil surface is susceptible to erosion by wind. The dust record for the last 20 years indicates that wind erosion...

Drawing a representative sample from the NCSS soil database: Building blocks for the national wind erosion network

USDA-ARS?s Scientific Manuscript database

Developing national wind erosion models for the continental United States requires a comprehensive spatial representation of continuous soil particle size distributions (PSD) for model input. While the current coverage of soil survey is nearly complete, the most detailed particle size classes have c...

Soil characteristics and associated wind erosion potential altered by oilseeds in wheat-based cropping systems

USDA-ARS?s Scientific Manuscript database

Oilseeds are integral to the production of biofuels and diversifying rainfed cropping systems in the Pacific Northwest. However, there is evidence to suggest greater potential for wind erosion when growing oilseeds in wheat-based rotations when tillage is used during fallow. Little is known concerni...

Nitrogen loss associated with wind erosion of agricultural lands in the Columbia Plateau, USA

USDA-ARS?s Scientific Manuscript database

Wind erosion causes environmental degradation as a result of suspension of dust in the atmosphere and deposition of sediment in surface water systems. For example, windblown dust is a concern in the Columbia Plateau region of the Pacific Northwest USA because airborne particulates contribute to exce...

Soil property effects on wind erosion of organic soils

USDA-ARS?s Scientific Manuscript database

Histosols (also known as organic soils, mucks, or peats) are soils that are dominated by organic matter (>20%) in half or more of the upper 80 cm. Forty four states have a total of 21 million ha of histosols in the United States. These soils, when intensively cropped, are subject to wind erosion r...

Soil Property Effects on Wind Erosion of Organic Soils

USDA-ARS?s Scientific Manuscript database

Histosols (also known as organic soils, mucks, or peats) are soils that are dominated by organic matter (>20%) in half or more of the upper 80 cm. Forty four states have a total of 21 million ha of histosols in the United States. These soils, when intensively cropped, are subject to wind erosion r...

Validation of SWEEP for creep, saltation, and suspension in a desert-oasis ecotone

USDA-ARS?s Scientific Manuscript database

Wind erosion in the desert-oasis ecotone can accelerate desertification and thus impacts oasis ecological security. Little is known about the susceptibility of the desert-oasis ecotone to wind erosion in the Tarim Basin even though the ecotone is a major source of windblown dust in China. The object...

Radar remote sensing of wind-driven land degradation processes in northeastern Patagonia.

PubMed

del Valle, H F; Blanco, P D; Metternicht, G I; Zinck, J A

2010-01-01

Wind-driven land degradation negatively impacts on rangeland production and infrastructure in the Valdes Peninsula, northeastern Patagonia. The Valdes Peninsula has the most noticeable dunefields of the Patagonian drylands. Wind erosion has been assessed at different scales in this region, but often with limited data. In general, terrain features caused by wind activity are better discriminated by active microwaves than by sensors operating in the visible and infrared regions of the electromagnetic spectrum. This paper aims to analyze wind-driven land degradation processes that control the radar backscatter observed in different sources of radar imagery. We used subsets derived from SIR-C, ERS-1 and 2, ENVISAT ASAR, RADARSAT-1, and ALOS PALSAR data. The visibility of aeolian features on radar images is mostly a function of wavelength, polarization, and incidence angle. Stabilized sand deposits are clearly observed in radar images, with defined edges but also signals of ongoing wind erosion. One of the most conspicuous features corresponds to old track sand dunes, a mixture of active and inactive barchanoid ridges and parabolic dunes. This is a clear example of deactivation of migrating dunes under the influence of vegetation. The L-band data reveal details of these sand ridges, whereas the C-band data only allow detecting a few of the larger tracks. The results of this study enable us to make recommendations about the utility of some radar sensor configurations for wind-driven land degradation reconnaissance in mid-latitude regions.

Advances in soil erosion research: processes, measurement, and modeling

USDA-ARS?s Scientific Manuscript database

Soil erosion by the environmental agents of water and wind is a continuing global menace that threatens the agricultural base that sustains our civilization. Members of ASABE have been at the forefront of research to understand erosion processes, measure erosion and related processes, and model very...

Evaluation of two empirical wind erosion models in arid and semi-arid regions of China and the USA

USDA-ARS?s Scientific Manuscript database

The Tarim Basin in China and Columbia Plateau in the USA are important agricultural regions as well as source regions of windblown dust that impact air quality in Asia and North America. Wind erosion models are important tools for assessing the potential erodibility of soils and best management prac...

The National Wind Erosion Research Network: Building a standardized long-term data resource for aeolian research, modeling and land management

USDA-ARS?s Scientific Manuscript database

The National Wind Erosion Research Network was established in 2014 as a collaborative effort led by the United States Department of Agriculture’s Agricultural Research Service and Natural Resources Conservation Service, and the United States Department of the Interior Bureau of Land Management, to a...

30 CFR 715.18 - Dams constructed of or impounding waste material.

Code of Federal Regulations, 2012 CFR

2012-07-01

... overtopping by wind and wave action. (iii) Dams shall have minimum safety factors as follows: Case Loading... abutments shall be controlled to prevent excessive uplift pressures, internal erosion, sloughing, removal of... before construction begins. (8) All dams shall be removed and the disturbed areas regraded, revegetated...

30 CFR 715.18 - Dams constructed of or impounding waste material.

Code of Federal Regulations, 2014 CFR

2014-07-01

... overtopping by wind and wave action. (iii) Dams shall have minimum safety factors as follows: Case Loading... abutments shall be controlled to prevent excessive uplift pressures, internal erosion, sloughing, removal of... before construction begins. (8) All dams shall be removed and the disturbed areas regraded, revegetated...

30 CFR 715.18 - Dams constructed of or impounding waste material.

Code of Federal Regulations, 2013 CFR

2013-07-01

... overtopping by wind and wave action. (iii) Dams shall have minimum safety factors as follows: Case Loading... abutments shall be controlled to prevent excessive uplift pressures, internal erosion, sloughing, removal of... before construction begins. (8) All dams shall be removed and the disturbed areas regraded, revegetated...

Wind streaks in Tharsis and Elysium - Implications for sediment transport by slope winds

NASA Astrophysics Data System (ADS)

Lee, S. W.; Thomas, P. C.; Veverka, J.

1982-11-01

Detailed maps of wind streaks in Tharsis and Elysium have been compiled from Viking Orbiter observations spanning one complete Martian year. The streak pattern is controlled by slope winds on the central volcanoes and on the flanks of the Tharsis bulge, while the global circulation dominates in Elysium. Dust erosion by downslope winds occurs over much of Tharsis and in the vicinity of Elysium Mons; this process is effective even at the low atmospheric pressures found near the summits of the large volcanoes. Erosional streaks are largely absent in Elysium Planitia; net deposition of dust might have occurred during the period of the observations. Surface properties such as slope, thermal inertia, and roughness may influence the efficiency of slope wind production sufficiently to account for the pronounced differences in streak types and patterns present in these two regions.

Changes in wind erosion over a 25-year restoration chronosequence on the south edge of the Tengger Desert, China: implications for preventing desertification.

PubMed

Ma, Quanlin; Fehmi, Jeffrey S; Zhang, Dekui; Fan, Baoli; Chen, Fang

2017-08-23

Wind erosion is a primary cause of desertification as well as being a serious ecological problem in arid and semi-arid areas across the world. To determine mechanisms for restoring desertified lands, an unrestored shifting sand dune and three formerly shifting sand dunes (desertified lands) that had been enclosed and afforested for 5, 15, and 25 years were selected for evaluation on the south edge of the Tengger Desert, China. Based on sampling heights between 0.2 and 3 m, the critical threshold average wind speed was 6.5 m s -1 at 2 m where the sand transport rate was reduced from 285.9 kg m -2  h -1 on the unrestored dunes to 9.1 and 1.8 kg m -2  h -1 on the sites afforested and enclosed for 5 and 15 years, respectively. The percentage of wind eroded area was reduced from 99.9% on the unrestored dune to 94.5, 9.0, and 0.5% on the sites afforested and enclosed for 5, 15, and 25 years, respectively. Wind erosion was effectively reduced after 15 years. Although there were different driving factors for wind erosion mitigation on the different restoration stages, an increase in the vegetation cover, surface roughness, soil shear strength, soil clay content, organic matter, and reduction in the near-surface wind speed were the primary variables associated with the restoration chronosequence. We conclude that reducing the wind speed and developing a biological crust through vegetation restoration were the critical components for restoration of desertified land.

Soil tillage and windbreak effects on millet and cowpea: I. Wind speed, evaporation, and wind erosion

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

Banzhaf, J.; Leihner, D.E.; Buerkert, A.

Deforestation, overgrazing, and declining soil regeneration periods have resulted in increased wind erosion problems in dry areas of the West African Sahel, but little is known about the bio-physical factors involved. This research was conducted to determine the effects of ridging and four different windbreak spacings on wind erosion, potential evaporation, and soil water reserves. A field trial was conducted from 1985 to 1987 on 12 ha of a Psammentic Paleustalf in Southern Niger. Millet, Pennisetum glaucum (L.), and cowpea, Vigna unguiculata (L.) Walp., were seeded in strips on flat and ridged soil. Windbreaks of savannah vegetation were spaced atmore » 6, 20, 40, and 90 m. The effects of ridging on wind speed, evaporation, and wind erosion were small and mostly non-significant. However, average wind speed at 0.3 m above ground in the center of cowpea and millet strips was significantly reduced from 2.8 to 2.1 m s[sup [minus]1] as windbreak distances narrowed from 90 to 6 m. As a consequence, potential evaporation declined by 15% and the amount of windblown soil particles by 50% in ridged and by 70% in flat treatments. Despite reduced potential evaporation, average subsoil water reserves were 14 mm smaller in the 6- than in the 20-m windbreak spacing indicating excessive water extraction by the windbreak vegetation. Thus, establishing windbreaks with natural savannah vegetation may require a careful consideration of the agronomic benefits and costs to competing crops. 21 refs., 5 figs.« less

Critical width of tidal flats triggers marsh collapse in the absence of sea-level rise

PubMed Central

Mariotti, Giulio; Fagherazzi, Sergio

2013-01-01

High rates of wave-induced erosion along salt marsh boundaries challenge the idea that marsh survival is dictated by the competition between vertical sediment accretion and relative sea-level rise. Because waves pounding marshes are often locally generated in enclosed basins, the depth and width of surrounding tidal flats have a pivoting control on marsh erosion. Here, we show the existence of a threshold width for tidal flats bordering salt marshes. Once this threshold is exceeded, irreversible marsh erosion takes place even in the absence of sea-level rise. This catastrophic collapse occurs because of the positive feedbacks among tidal flat widening by wave-induced marsh erosion, tidal flat deepening driven by wave bed shear stress, and local wind wave generation. The threshold width is determined by analyzing the 50-y evolution of 54 marsh basins along the US Atlantic Coast. The presence of a critical basin width is predicted by a dynamic model that accounts for both horizontal marsh migration and vertical adjustment of marshes and tidal flats. Variability in sediment supply, rather than in relative sea-level rise or wind regime, explains the different critical width, and hence erosion vulnerability, found at different sites. We conclude that sediment starvation of coastlines produced by river dredging and damming is a major anthropogenic driver of marsh loss at the study sites and generates effects at least comparable to the accelerating sea-level rise due to global warming. PMID:23513219

Critical width of tidal flats triggers marsh collapse in the absence of sea-level rise.

PubMed

Mariotti, Giulio; Fagherazzi, Sergio

2013-04-02

High rates of wave-induced erosion along salt marsh boundaries challenge the idea that marsh survival is dictated by the competition between vertical sediment accretion and relative sea-level rise. Because waves pounding marshes are often locally generated in enclosed basins, the depth and width of surrounding tidal flats have a pivoting control on marsh erosion. Here, we show the existence of a threshold width for tidal flats bordering salt marshes. Once this threshold is exceeded, irreversible marsh erosion takes place even in the absence of sea-level rise. This catastrophic collapse occurs because of the positive feedbacks among tidal flat widening by wave-induced marsh erosion, tidal flat deepening driven by wave bed shear stress, and local wind wave generation. The threshold width is determined by analyzing the 50-y evolution of 54 marsh basins along the US Atlantic Coast. The presence of a critical basin width is predicted by a dynamic model that accounts for both horizontal marsh migration and vertical adjustment of marshes and tidal flats. Variability in sediment supply, rather than in relative sea-level rise or wind regime, explains the different critical width, and hence erosion vulnerability, found at different sites. We conclude that sediment starvation of coastlines produced by river dredging and damming is a major anthropogenic driver of marsh loss at the study sites and generates effects at least comparable to the accelerating sea-level rise due to global warming.

[Functions of different cultivation modes in oasis agriculture on soil wind erosion control and soil moisture conservation].

PubMed

Su, Peixi; Zhao, Aifen; Du, Mingwu

2004-09-01

During 2001-2002, the effects of different cultivation modes including winter irrigation and zero tillage, crop-grass intercropping, and early spring film mulching on sand entrainment, wind velocity gradient and soil moisture conservation were studied in the middle reaches of the Heihe River in the Hexi Corridor region. The results showed that all these modes could reduce soil wind erosion and halt sand entrainment to different degrees. Compared with the bare fields exposed by spring plowing, early spring film mulching could increase soil moisture storage by 35.6%. At present, spring plowing and sowing was a main factor responsible to the occurrence of sand storms and the increase in suspended dust content. Farmlands in the upper and middle reaches of the Heihe River generally produced a dust transport up to 4.8-6.0 million tons per year, which was higher than that of sandy desert in the same region. In the Hexi Corridor region, the suspended dust amount produced from 1 hm2 farmland was equivalent to that of 1.5 hm2 desert.

Wind tunnel experiments: influence of erosion and deposition on wind-packing of new snow

NASA Astrophysics Data System (ADS)

Sommer, Christian G.; Lehning, Michael; Fierz, Charles

2018-01-01

Wind sometimes creates a hard, wind-packed layer at the surface of a snowpack. The formation of such wind crusts was observed during wind tunnel experiments with combined SnowMicroPen and Microsoft Kinect sensors. The former provides the hardness of new and wind-packed snow and the latter spatial snow depth data in the test section. Previous experiments showed that saltation is necessary but not sufficient for wind-packing. The combination of hardness and snow depth data now allows to study the case with saltation in more detail. The Kinect data requires complex processing but with the appropriate corrections, snow depth changes can be measured with an accuracy of about 1 mm. The Kinect is therefore well suited to quantify erosion and deposition. We found that no hardening occurred during erosion and that a wind crust may or may not form when snow is deposited. Deposition is more efficient at hardening snow in wind-exposed than in wind-sheltered areas. The snow hardness increased more on the windward side of artificial obstacles placed in the wind tunnel. Similarly, the snow was harder in positions with a low Sx parameter. Sx describes how wind-sheltered (high Sx) or wind-exposed (low Sx) a position is and was calculated based on the Kinect data. The correlation between Sx and snow hardness was -0.63. We also found a negative correlation of -0.4 between the snow hardness and the deposition rate. Slowly deposited snow is harder than a rapidly growing accumulation. Sx and the deposition rate together explain about half of the observed variability of snow hardness.

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 differences in controls between sampling periods with high/low wind-wave activity. In particular, analyses show the important influence of wave energy, land cover type, and landscape geomorphic history on modern coastal erosion dynamics.

Measurement and Modeling of Fugitive Dust from Off Road DoD Activities

DTIC Science & Technology

2017-12-08

each soil and vehicle type (see Table 2). Note, no tracked vehicles were run at YTC. CT is the curve track sampling location, CR is the curve ridge...Soil is SL = sandy loam. ...................... 116 Figure 35. Single-event Wind Erosion Evaluation Program (SWEEP) Run example results. ... 121...Figure 36. Single-event Wind Erosion Evaluation Program (SWEEP) Threshold Run example results screen

A large source of dust missing in particulate matter emission inventories? Wind erosion of post-fire landscapes

Treesearch

N. S. Wagenbrenner; S. H. Chung; B. K. Lamb

2017-01-01

Wind erosion of soils burned by wildfire contributes substantial particulate matter (PM) in the form of dust to the atmosphere, but the magnitude of this dust source is largely unknown. It is important to accurately quantify dust emissions because they can impact human health, degrade visibility, exacerbate dust-on-snow issues (including snowmelt timing, snow chemistry...

Dust emissions of organic soils observed in the field and laboratory

NASA Astrophysics Data System (ADS)

Zobeck, T. M.; Baddock, M. C.; Guo, Z.; Van Pelt, R.; Acosta-Martinez, V.; Tatarko, J.

2011-12-01

According to the U.S. Soil Taxonomy, Histosols (also known as organic soils) are soils that are dominated by organic matter (>20% organic matter) in half or more of the upper 80 cm. These soils, when intensively cropped, are subject to wind erosion resulting in loss in crop productivity and degradation of soil, air, and water quality. Estimating wind erosion on Histosols has been determined by USDA-Natural Resources Conservation Service as a critical need for the Wind Erosion Prediction System (WEPS) model. WEPS has been developed to simulate wind erosion on agricultural land in the US, including soils with organic soil material surfaces. However, additional field measurements are needed to calibrate and validate estimates of wind erosion of organic soils using WEPS. In this study, we used a field portable wind tunnel to generate suspended sediment (dust) from agricultural surfaces for soils with a range of organic contents. The soils were tilled and rolled to provide a consolidated, friable surface. Dust emissions and saltation were measured using an isokinetic vertical slot sampler aspirated by a regulated suction source. Suspended dust was collected on filters of the dust slot sampler and sampled at a frequency of once every six seconds in the suction duct using a GRIMM optical particle size analyzer. In addition, bulk samples of airborne dust were collected using a sampler specifically designed to collect larger dust samples. The larger dust samples were analyzed for physical, chemical, and microbiological properties. In addition, bulk samples of the soils were tested in a laboratory wind tunnel similar to the field wind tunnel and a laboratory dust generator to compare field and laboratory results. For the field wind tunnel study, there were no differences between the highest and lowest organic content soils in terms of their steady state emission rate under an added abrader flux, but the soil with the mid-range of organic matter had less emission by one third. In the laboratory wind tunnel, samples with the same ratio of erodible to non-erodible aggregates as the field soils were abraded and dust emissions were observed with the same sampling system as used in the field wind tunnel. In the dust generator, 5 gm samples < 8 mm diameter of each organic soil were rotated in a 50 cm long tube and the dust generated was observed with the GRIMM during a 20 minute run. Comparisons of the field dust emission rates with the laboratory results will be presented.

Landscape evolution on Mars - A model of aeolian denudation in Gale Crater

NASA Astrophysics Data System (ADS)

Day, M. D.; Kocurek, G.; Grotzinger, J. P.

2015-12-01

Aeolian erosion has been the dominant geomorphic agent to shape the surface of Mars for the past ~3.5 billion years. Although individual geomorphic features evidencing aeolian activity are well understood (e.g., yardangs, dune fields, and wind streaks), landscapes formed by aeolian erosion remain poorly characterized. Intra-crater sedimentary mounds are hypothesized to have formed by wind deflation of craters once filled with flat-lying strata, and, therefore, should be surrounded by landscapes formed by aeolian erosion. Here we present a landscape evolution model that provides both an initial characterization of aeolian landscapes, and a mechanism for large-scale excavation. Wind excavation of Gale Crater to form the 5 km high Mount Sharp would require removal of 6.4 x 104 km3 of sediment. Imagery in Gale Crater from satellites and the Mars Science Laboratory rover Curiosity shows a surface characterized by first-cycle aeolian erosion of bedrock. The overall landscape is interpreted to represent stages in a cycle of aeolian deflation and excavation, enhanced by physical weathering (e.g., thermal fracturing, cratering). Initial wind erosion of bedrock is enhanced along fractures, producing retreating scarps. Underlying less resistant layers then erode faster than the armoring cap rock, increasing relief in scarps to form retreating mesas. As scarp retreat continues, boulders from the armoring cap unit break away and cover the hillslopes of less resistant material below the scarps. Eventually all material from the capping unit is eroded away and a boulder-capped hill remains. Winnowing of fine material flattens hillslope topography, leaving behind a desert pavement. Over long enough time, this pavement is breached and the cycle begins anew. This cycle of landscape denudation by the wind is similar to that of water, but lacks characteristic subaqueous features such as dendritic drainage networks.

Field wind tunnel testing of two silt loam soils on the North American Central High Plains

NASA Astrophysics Data System (ADS)

Scott Van Pelt, R.; Baddock, Matthew C.; Zobeck, Ted M.; Schlegel, Alan J.; Vigil, Merle F.; Acosta-Martinez, Veronica

2013-09-01

Wind erosion is a soil degrading process that threatens agricultural sustainability and environmental quality globally. Protecting the soil surface with cover crops and plant residues, practices common in no-till and reduced tillage cropping systems, are highly effective methods for shielding the soil surface from the erosive forces of wind and have been credited with beneficial increases of chemical and physical soil properties including soil organic matter, water holding capacity, and wet aggregate stability. Recently, advances in biofuel technology have made crop residues valuable feed stocks for ethanol production. Relatively little is known about cropping systems effects on intrinsic soil erodibility, the ability of the soil without a protective cover to resist the erosive force of wind. We tested the bare, uniformly disturbed, surface of long-term tillage and crop rotation research plots containing silt loam soils in western Kansas and eastern Colorado with a portable field wind tunnel. Total Suspended Particulate (TSP) were measured using glass fiber filters and respirable dust, PM10 and PM2.5, were measured using optical particle counters sampling the flow to the filters. The results were highly variable and TSP emission rates varied from less than 0.5 mg m-2 s-1 to greater than 16.1 mg m-2 s-1 but all the results indicated that cropping system history had no effect on intrinsic erodibility or dust emissions from the soil surfaces. We conclude that prior best management practices will not protect the soil from the erosive forces of wind if the protective mantle of crop residues is removed.

Responses of wind erosion to climate-induced vegetation changes on the Colorado Plateau.

PubMed

Munson, Seth M; Belnap, Jayne; Okin, Gregory S

2011-03-08

Projected increases in aridity throughout the southwestern United States due to anthropogenic climate change will likely cause reductions in perennial vegetation cover, which leaves soil surfaces exposed to erosion. Accelerated rates of dust emission from wind erosion have large implications for ecosystems and human well-being, yet there is poor understanding of the sources and magnitude of dust emission in a hotter and drier climate. Here we use a two-stage approach to compare the susceptibility of grasslands and three different shrublands to wind erosion on the Colorado Plateau and demonstrate how climate can indirectly moderate the magnitude of aeolian sediment flux through different responses of dominant plants in these communities. First, using results from 20 y of vegetation monitoring, we found perennial grass cover in grasslands declined with increasing mean annual temperature in the previous year, whereas shrub cover in shrublands either showed no change or declined as temperature increased, depending on the species. Second, we used these vegetation monitoring results and measurements of soil stability as inputs into a field-validated wind erosion model and found that declines in perennial vegetation cover coupled with disturbance to biological soil crust resulted in an exponential increase in modeled aeolian sediment flux. Thus the effects of increased temperature on perennial plant cover and the correlation of declining plant cover with increased aeolian flux strongly suggest that sustained drought conditions across the southwest will accelerate the likelihood of dust production in the future on disturbed soil surfaces.

Responses of wind erosion to climate-induced vegetation changes on the Colorado Plateau

USGS Publications Warehouse

Munson, Seth M.; Belnap, Jayne; Okin, Gregory S.

2011-01-01

Projected increases in aridity throughout the southwestern United States due to anthropogenic climate change will likely cause reductions in perennial vegetation cover, which leaves soil surfaces exposed to erosion. Accelerated rates of dust emission from wind erosion have large implications for ecosystems and human well-being, yet there is poor understanding of the sources and magnitude of dust emission in a hotter and drier climate. Here we use a two-stage approach to compare the susceptibility of grasslands and three different shrublands to wind erosion on the Colorado Plateau and demonstrate how climate can indirectly moderate the magnitude of aeolian sediment flux through different responses of dominant plants in these communities. First, using results from 20 y of vegetation monitoring, we found perennial grass cover in grasslands declined with increasing mean annual temperature in the previous year, whereas shrub cover in shrublands either showed no change or declined as temperature increased, depending on the species. Second, we used these vegetation monitoring results and measurements of soil stability as inputs into a field-validated wind erosion model and found that declines in perennial vegetation cover coupled with disturbance to biological soil crust resulted in an exponential increase in modeled aeolian sediment flux. Thus the effects of increased temperature on perennial plant cover and the correlation of declining plant cover with increased aeolian flux strongly suggest that sustained drought conditions across the southwest will accelerate the likelihood of dust production in the future on disturbed soil surfaces.

Responses of wind erosion to climate-induced vegetation changes on the Colorado Plateau

PubMed Central

Munson, Seth M.; Belnap, Jayne; Okin, Gregory S.

2011-01-01

Projected increases in aridity throughout the southwestern United States due to anthropogenic climate change will likely cause reductions in perennial vegetation cover, which leaves soil surfaces exposed to erosion. Accelerated rates of dust emission from wind erosion have large implications for ecosystems and human well-being, yet there is poor understanding of the sources and magnitude of dust emission in a hotter and drier climate. Here we use a two-stage approach to compare the susceptibility of grasslands and three different shrublands to wind erosion on the Colorado Plateau and demonstrate how climate can indirectly moderate the magnitude of aeolian sediment flux through different responses of dominant plants in these communities. First, using results from 20 y of vegetation monitoring, we found perennial grass cover in grasslands declined with increasing mean annual temperature in the previous year, whereas shrub cover in shrublands either showed no change or declined as temperature increased, depending on the species. Second, we used these vegetation monitoring results and measurements of soil stability as inputs into a field-validated wind erosion model and found that declines in perennial vegetation cover coupled with disturbance to biological soil crust resulted in an exponential increase in modeled aeolian sediment flux. Thus the effects of increased temperature on perennial plant cover and the correlation of declining plant cover with increased aeolian flux strongly suggest that sustained drought conditions across the southwest will accelerate the likelihood of dust production in the future on disturbed soil surfaces. PMID:21368143

Wind Texture

NASA Image and Video Library

2010-11-10

One of the most active agent of erosion on Mars today is the wind. This region, near Nicholson crater, has been sculpted by untold years of blowing grit and wind, as shown in this image captured by NASA Mars Odyssey.

DESIGN INFORMATION REPORT: PROTECTION OF WASTEWATER LAGOON INTERIOR SLOPES

EPA Science Inventory

A problem common to many wastewater treatment and storage lagoons is erosion of the interior slopes. Erosion may be caused by surface runoff and wind-induced wave action. The soils that compose the steep interior slopes of lagoons are especially susceptible to erosion and slumpin...

Decision Theories used in Areas Planning around La Colacha Basin (Cordoba, Argentina) considering Natural and Human Hazards

NASA Astrophysics Data System (ADS)

Antón, Jose M.; Grau, Juan B.; Tarquis, A. M.; Cisneros, Jose M.; Andina, Diego

2010-05-01

The authors of U.P.M. have had relations with Argentine Universities and Administrations, in part with J.M.Cisneros that is Professor at Universidad Nacional de Rio Cuarto in Prov. de Córdoba Arg., and have applied Decision Theories with Mathematic tools for the planning of defences and uses of soils in these areas and especially of La Colacha bassin enlarged with larger areas around it as "Cuenca de los Arroyos Menores" at West and South of Rio Cuarto. These large flat lands have loess soils brought by winds from Los Andes that are much far at West, there is a very old line of not high mountains at West near the study area from which rivers flow with little slopes to somehow lower flat areas at West with some marshes. Rivers through loess get regressive erosions with rains forming kilometres long ditches in the loess called "cárcavas" some meters deep and quite large across otherwise flat agricultural lands, and J.M. Cisneros, that has numerous publications about local soil uses, has directed diverse genie rural works to halt the regression of some of them. Part of the study is about protection against floods and "cárcavas". There are famous experiences and records of higher inundations of large areas by rivers. Latitude of Rio Cuarto is 31°25' South, that area is temperate refreshed by south winds, Zonda föhn winds from West being hotter and drier, and there are monsoons and so winter in July is dry and summer and December has rains, that average 829mm per year. Wind erosion and fires occur frequently on these loess soils in winter. This is an excellent area for agriculture but some actual uses may be not sustainable in long term such as excesses with genetically engineered soy, and the authors have studied aided with mathematical models (ELECTRE I, PROMETHEE and Expert Choice) the preferences of various alternative systems of land use (Autochthonous forest, High value forest, Traditional farms, Erosion control Crop with agriculture use, and Erosion control Crop with industrial use (biomass) ) in view of diverse Criteria (Water erosion index, Eolian erosion index, Implementation facility, Water resources, Economical Benefits, Hand power, Environmental Impacts, social Acceptance), as contribution for territorial planning, in part in relation with local official agencies. There are numerous references in local Spanish Argentine literature about the region uses of soils, some of J.M.Cisneros, and many general references, let note about Decision Theory: (1) Grau, J. B., Antón, J.M., Tarquis A. M., Andina, D. Election of water Resources Management Entity using a Multi-criteria decision (MCD) Method in Salta Province (Argentine)". CITSA 2008, Orlando 29 June-2 July, 2008. (2) Roy, B., D. Bouyssou. Aidé Multicritère à la Décision: Méthodes et cas. Economica, Paris 1993. (3) Saaty, T. The Analytic Hierarchy Process, Mac Graw-Hill, New York, 1980.

Soil property effects on wind erosion of organic soils

NASA Astrophysics Data System (ADS)

Zobeck, Ted M.; Baddock, Matthew; Scott Van Pelt, R.; Tatarko, John; Acosta-Martinez, Veronica

2013-09-01

Histosols (also known as organic soils, mucks, or peats) are soils that are dominated by organic matter (OM > 20%) in half or more of the upper 80 cm. Forty two states have a total of 21 million ha of Histosols in the United States. These soils, when intensively cropped, are subject to wind erosion resulting in loss of crop productivity and degradation of soil, air, and water quality. Estimating wind erosion on Histosols has been determined by USDA-Natural Resources Conservation Service (NRCS) as a critical need for the Wind Erosion Prediction System (WEPS) model. WEPS has been developed to simulate wind erosion on agricultural land in the US, including soils with organic soil material surfaces. However, additional field measurements are needed to understand how soil properties vary among organic soils and to calibrate and validate estimates of wind erosion of organic soils using WEPS. Soil properties and sediment flux were measured in six soils with high organic contents located in Michigan and Florida, USA. Soil properties observed included organic matter content, particle density, dry mechanical stability, dry clod stability, wind erodible material, and geometric mean diameter of the surface aggregate distribution. A field portable wind tunnel was used to generate suspended sediment and dust from agricultural surfaces for soils ranging from 17% to 67% organic matter. The soils were tilled and rolled to provide a consolidated, friable surface. Dust emissions and saltation were measured using an isokinetic vertical slot sampler aspirated by a regulated suction source. Suspended dust was sampled using a Grimm optical particle size analyzer. Particle density of the saltation-sized material (>106 μm) was inversely related to OM content and varied from 2.41 g cm-3 for the soil with the lowest OM content to 1.61 g cm-3 for the soil with highest OM content. Wind erodible material and the geometric mean diameter of the surface soil were inversely related to dry clod stability. The effect of soil properties on sediment flux varied among flux types. Saltation flux was adequately predicted with simple linear regression models. Dry mechanical stability was the best single soil property linearly related to saltation flux. Simple linear models with soil properties as independent variables were not well correlated with PM10E values (mass flux). A second order polynomial equation with OM as the independent variable was found to be most highly correlated with PM10E values. These results demonstrate that variations in sediment and dust emissions can be linked to soil properties using simple models based on one or more soil properties to estimate saltation mass flux and PM10E values from organic and organic-rich soils.

Examining possible causes of mortality in white pine seedlings

Treesearch

Elizabeth Gilles; Ronald Reitz; Greg Hoss; David. Gwaze

2011-01-01

White pine (Pinus strobus L.) is one of the most important timber trees in the northeastern United States and eastern Canada (Demeritt and Garrett 1996). White pine is not native to Missouri; it is commonly planted for wind breaks and erosion control and as an ornamental. Unusual mortality of bare-root seedlings of white pine purchased from the...

Manufacturing issues which affect coating erosion performance in wind turbine blades

NASA Astrophysics Data System (ADS)

Cortés, E.; Sánchez, F.; Domenech, L.; Olivares, A.; Young, T. M.; O'Carroll, A.; Chinesta, F.

2017-10-01

Erosion damage, caused by repeated rain droplet impact on the leading edges of wind turbine blades, is a major cause for cost concern. Resin Infusion (RI) is used in wind energy blades where low weight and high mechanical performance materials are demanded. The surface coating plays a crucial role in the manufacturing and performance response. The Leading Edge coating is usually moulded, painted or sprayed onto the blade surface so adequate adhesion in the layers' characterization through the thickness is required for mechanical performance and durability reasons. In the current work, an investigation has been directed into the resulting rain erosion durability of the coating was undertaken through a combination of mass loss testing measurements with manufacturing processing parameter variations. The adhesion and erosion is affected by the shock wave caused by the collapsing water droplet on impact. The stress waves are transmitted to the substrate, so microestructural discontinuities in coating layers and interfaces play a key role on its degradation. Standard industrial systems are based on a multilayer system, with a high number of interfaces that tend to accelerate erosion by delamination. Analytical and numerical models are commonly used to relate lifetime prediction and to identify suitable coating and composite substrate combinations and their potential stress reduction on the interface. In this research, the input parameters for the appropriate definition of the Cohesive Zone Modelling (CZM) of the coating-substrate interface are outlined by means of Pull off testing and Peeling testing results. It allowed one to optimize manufacturing and coating process for blades into a knowledge-based guidance for leading edge coating material development. It was achieved by investigating the erosion degradation process using both numerical and laboratory techniques (Pull off, Peeling and Rain Erosion Testing in a whirling arm rain erosion test facility).

Microdunes and other aeolian bedforms on Venus - Wind Tunnel simulations

NASA Technical Reports Server (NTRS)

Greeley, R.; Marshall, J. R.; Leach, R. N.

1984-01-01

The development of aeolian bedforms in the simulated Venusian environment has been experimentally studied in the Venus Wind Tunnel. It is found that the development of specific bedforms, including ripples, dunes, and 'waves', as well as their geometry, are controlled by a combination of factors including particle size, wind speed, and atmospheric density. Microdunes are formed which are analogous to full-size terrestrial dunes and are characterized by the development of slip faces, internal cross-bedding, a low ratio of saltation path length to dune length, and a lack of particle-size sorting. They begin to develop at wind speeds just above saltation threshold and evolve into waves at higher velocities. At wind speeds of about 1.5 m/sec and higher, the bed is flat and featureless. This evolution is explained by a model based on the interaction of alternating zones of erosion and deposition and particle saltation distances.

Microdunes and Other Aeolian Bedforms on Venus: Wind Tunnel Simulations

NASA Technical Reports Server (NTRS)

Greeley, R.; Marshall, J. R.; Leach, R. N.

1985-01-01

The development of aeolian bedforms in the simulated Venusian environment has been experimentally studied in the Venus Wind tunnel. It is found that the development of specific bedforms, including ripples, dunes, and waves, as well as their geometry, are controlled by a combination of factors including particle size, wind speed, and atmospheric density. Microdunes are formed which are analogous to full-size terrestrial dunes and are characterized by the development of slip faces, internal cross-bedding, a low ratio of saltation path length to dune length, and a lack of particle-size sorting. They begin to develop at wind speeds just above saltation threshold and evolve into waves at higher velocities. At wind speeds of about 1.5 m/sec and higher, the bed is flat and featureless. This evolution is explained by a model based on the interaction of alternating zones of erosion and deposition and particle saltation distances.

Wind erosion reduces soil organic carbon sequestration falsely indicating ineffective management practices

NASA Astrophysics Data System (ADS)

Chappell, Adrian; Baldock, Jeffrey A.

2016-09-01

Improved management of agricultural land has the potential to reduce greenhouse gas emissions and to reduce atmospheric CO2 via soil carbon sequestration. However, SOC stocks are reduced by soil erosion which is commonly omitted from calculations of crop production, C cycling, C sequestration and C accounting. We used fields from the wind eroded dryland cropping region of Western Australia to demonstrate the global implications for C sequestration and C accounting of omitting soil erosion. For the fields we previously estimated mean net (1950s-1990) soil erosion of 1.2 ± 1.0 t ha-1 y-1. The mean net (1990-2013) soil erosion increased by nearly four times to 4.4 ± 2.1 t ha-1 y-1. Conservation agriculture has evidently not reduced wind erosion in this region. The mean net (1990-2013) SOC erosion was up to 0.2 t C ha-1 y-1 across all sampled fields and similar to measured sequestration rates in the region (up to 0.5 t C ha-1 y-1; 10 years) for many management practices recommended for building SOC stocks. The minimum detectable change (MDC; 10 years) of SOC without erosion was up to 0.2 t C ha-1 y-1 whilst the MDC of SOC with erosion was up to 0.4 t C ha-1 y-1. These results illustrate the generally applicable outcome: (i) if SOC erosion is equal to (or greater than) the increase in SOC due to management practices, the change will not be detectable (or a loss will be evident); (ii) without including soil erosion in SOC sequestration calculations, the monitoring of SOC stocks will lead to, at best the inability to detect change and, at worst the false impression that management practices have failed to store SOC. Furthermore, continued omission of soil erosion in crop production, C accounting and C sequestration will most likely undermine confidence in policy designed to encourage adoption of C farming and the attendant benefits for soil stewardship and food security.

Multi-decadal impacts of grazing on soil physical and biogeochemical properties in southeast Utah

USGS Publications Warehouse

Neff, J.C.; Reynolds, R.L.; Belnap, J.; Lamothe, P.

2005-01-01

Many soils in southeastern Utah are protected from surface disturbance by biological soil crusts that stabilize soils and reduce erosion by wind and water. When these crusts are disturbed by land use, soils become susceptible to erosion. In this study, we compare a never-grazed grassland in Canyonlands National Park with two historically grazed sites with similar geologic, geomorphic, and geochemical characteristics that were grazed from the late 1800s until 1974. We show that, despite almost 30 years without livestock grazing, surface soils in the historically grazed sites have 38-43% less silt, as well as 14-51% less total elemental soil Mg, Na, P, and Mn content relative to soils never exposed to livestock disturbances. Using magnetic measurement of soil magnetite content (a proxy for the stabilization of far-traveled eolian dust) we suggest that the differences in Mg, Na, P, and Mn are related to wind erosion of soil fine particles after the historical disturbance by livestock grazing. Historical grazing may also lead to changes in soil organic matter content including declines of 60-70% in surface soil C and N relative to the never-grazed sites. Collectively, the differences in soil C and N content and the evidence for substantial rock-derived nutrient loss to wind erosion implies that livestock grazing could have long-lasting effects on the soil fertility of native grasslands in this part of southeastern Utah. This study suggests that nutrient loss due to wind erosion of soils should be a consideration for management decisions related to the long-term sustainability of grazing operations in arid environments.

Towards new-generation soil erosion modeling: Building a unified omnivorous model

USDA-ARS?s Scientific Manuscript database

Soil erosion is a global threat to agricultural production, and results in off-site sediment and nutrient losses that negatively impact water and air quality. Models are mathematical equations used to estimate the amount of soil lost from a land air, due to the erosive forces of water or wind. Early...

Erosion of Earthen Levees by Wave Action

NASA Astrophysics Data System (ADS)

Ozeren, Y.; Wren, D. G.; Reba, M. L.

2016-02-01

Earthen levees of aquaculture and irrigation reservoirs in the United States often experience significant erosion due to wind-generated waves. Typically constructed using local soils, unprotected levees are subjected to rapid erosion and retreat due to wind generated waves and surface runoff. Only a limited amount of published work addresses the erosion rates for unprotected levees, and producers who rely on irrigation reservoirs need an economic basis for selecting a protection method for vulnerable levees. This, in turn, means that a relationship between wave energy and erosion of cohesive soils is needed. In this study, laboratory experiments were carried out in order to quantify wave induced levee erosion and retreat. A model erodible bank was packed using a soil consisting of approximately 14% sand, 73% silt, and 13% clay in a 20.6 m long 0.7 m wide and 1.2 m deep wave tank at the USDA-ARS, National Sedimentation Laboratory in Oxford MS. The geometry of the levee face was monitored by digital camera and the waves were measured by means of 6 capacitance wave staffs. Relationships were established between levee erosion, edge and retreat rates, and incident wave energy.

Factors controlling threshold friction velocity in semiarid and arid areas of the United States

USGS Publications Warehouse

Marticorena, Beatrice; Bergametti, G.; Belnap, Jayne

1997-01-01

A physical model was developed to explain threshold friction velocities u*t for particles of the size 60a??120 I?m lying on a rough surface in loose soils for semiarid and arid parts of the United States. The model corrected for the effect of momentum absorption by the nonerodible roughness. For loose or disturbed soils the most important parameter that controls u*t is the aerodynamic roughness height z 0. For physical crusts damaged by wind the size of erodible crust pieces is important along with the roughness. The presence of cyanobacteriallichen soil crusts roughens the surface, and the biological fibrous growth aggregates soil particles. Only undisturbed sandy soils and disturbed soils of all types would be expected to be erodible in normal wind storms. Therefore disturbance of soils by both cattle and humans is very important in predicting wind erosion as confirmed by our measurements.

Predicting wind-driven waves in small reservoirs

USDA-ARS?s Scientific Manuscript database

The earthen levees commonly used for irrigation reservoirs are subjected to significant embankment erosion due to wind-generated waves. The design of bank protection measures relies on adequate prediction of wave characteristics based on wind conditions and fetch length. Current formulations are ba...

Climate Change and Its Impact on the Eco-Environment of the Three-Rivers Headwater Region on the Tibetan Plateau, China.

PubMed

Jiang, Chong; Zhang, Linbo

2015-09-25

This study analyzes the impact of climate change on the eco-environment of the Three-Rivers Headwater Region (TRHR), Tibetan Plateau, China. Temperature and precipitation experienced sharp increases in this region during the past 57 years. A dramatic increase in winter temperatures contributed to a rise in average annual temperatures. Moreover, annual runoff in the Lancang (LRB) and Yangtze (YARB) river basins showed an increasing trend, compared to a slight decrease in the Yellow River Basin (YRB). Runoff is predominantly influenced by rainfall, which is controlled by several monsoon systems. The water temperature in the YRB and YARB increased significantly from 1958 to 2007 (p < 0.001), driven by air temperature changes. Additionally, owing to warming and wetting trends in the TRHR, the net primary productivity (NPP) and normalized difference vegetation index (NDVI) showed significant increasing trends during the past half-century. Furthermore, although an increase in water erosion due to rainfall erosivity was observed, wind speeds declined significantly, causing a decline in wind erosion, as well as the frequency and duration of sandstorms. A clear regional warming trend caused an obvious increasing trend in glacier runoff, with a maximum value observed in the 2000s.

Climate Change and Its Impact on the Eco-Environment of the Three-Rivers Headwater Region on the Tibetan Plateau, China

PubMed Central

Jiang, Chong; Zhang, Linbo

2015-01-01

This study analyzes the impact of climate change on the eco-environment of the Three-Rivers Headwater Region (TRHR), Tibetan Plateau, China. Temperature and precipitation experienced sharp increases in this region during the past 57 years. A dramatic increase in winter temperatures contributed to a rise in average annual temperatures. Moreover, annual runoff in the Lancang (LRB) and Yangtze (YARB) river basins showed an increasing trend, compared to a slight decrease in the Yellow River Basin (YRB). Runoff is predominantly influenced by rainfall, which is controlled by several monsoon systems. The water temperature in the YRB and YARB increased significantly from 1958 to 2007 (p < 0.001), driven by air temperature changes. Additionally, owing to warming and wetting trends in the TRHR, the net primary productivity (NPP) and normalized difference vegetation index (NDVI) showed significant increasing trends during the past half-century. Furthermore, although an increase in water erosion due to rainfall erosivity was observed, wind speeds declined significantly, causing a decline in wind erosion, as well as the frequency and duration of sandstorms. A clear regional warming trend caused an obvious increasing trend in glacier runoff, with a maximum value observed in the 2000s. PMID:26404333

Characteristics of wind waves in shallow tidal basins and how they affect bed shear stress, bottom erosion, and the morphodynamic evolution of coupled marsh and mudflat landforms

NASA Astrophysics Data System (ADS)

Tommasini, Laura; Carniello, Luca; Goodwin, Guillaume; Mudd, Simon M.; Matticchio, Bruno; D'Alpaos, Andrea

2017-04-01

Wind-wave induced erosion is one of the main processes controlling the morphodynamic evolution of shallow tidal basins, because wind waves promote the erosion of subtidal platforms, tidal flats and salt marshes. Our study considered zero-, one-and two-dimensional wave models. First, we analyzed the relations between wave parameters, depth and bed shear stress with constant and variable wave period considering two zero-dimensional models based on the Young and Verhagen (1996), and Carniello et al. (2005, 2011) approaches. The first one is an empirical method that computes wave height and the variable wave period from wind velocity, fetch and water depth. The second one is based on the solution of wave action conservation equation, we use this second approach for computing the bottom shear stress and wave height, considering variable and constant (t=2s) wave period. Second, we compared the wave spectral model SWAN with a fully coupled Wind-Wave Tidal Model applied to a 1D rectangular domain. These models describe both the growth and propagation of wind waves. Finally, we applied the two-dimensional Wind Wave Tidal Model (WWTM) to six different configurations of the Venice lagoon considering the same boundary conditions and we evaluated the spatial variation of mean wave power density. The analysis with zero-dimensional models show that the effects of the different model assumptions on the wave period and on the wave height computation cannot be neglected. In particular, the relationships between bottom shear stress and water depth have different shapes. Two results emerge: first, the differences are higher for small depths, and then the maximum values reached with the Young and Verhagen (1996) approach are greater than the maximum values obtained with WWTM approach. The results obtained with two-dimensional models suggest that the wave height is different in particular for small fetch, this could be due to the different formulation of the wave period. Finally, the application of WWTM for the entire Lagoon basin underlines an increase of the mean power density in the last four centuries, in particular in the central-southern part of the lagoon between Chioggia and Malamocco inlets.

Aeolian Induced Erosion and Particle Entrainment

NASA Technical Reports Server (NTRS)

Saint, Brandon

2007-01-01

The Granular Physics Department at The Kennedy Space Center is addressing the problem of erosion on the lunar surface. The early stages of research required an instrument that would produce erosion at a specific rate with a specific sample variation. This paper focuses on the development and experimental procedures to measure and record erosion rates. This was done with the construction of an open air wind tunnel, and examining the relationship between airflow and particle motion.

An Assessment of the Impact of Urbanization on Soil Erosion in Inner Mongolia.

PubMed

Wang, Li-Yan; Xiao, Yi; Rao, En-Ming; Jiang, Ling; Xiao, Yang; Ouyang, Zhi-Yun

2018-03-19

Inner Mongolia, an autonomous region of the People's Republic of China, has experienced severe soil erosion following a period of rapid economic development and urbanization. To investigate how urbanization has influenced the extent of soil erosion in Inner Mongolia, we used urbanization and soil erosion data from 2000 through 2010 to determine the relationship between urbanization and soil erosion patterns. Two empirical equations-the Revised Universal Soil Loss Equation (RUSLE) and the Revised Wind Erosion Equation (RWEQ)-were used to estimate the intensity of soil erosion, and we performed backward linear regression to model how it changed with greater urbanization. There was an apparent increase in the rate of urbanization and a decrease in the area affected by soil erosion in 2010 compared to the corresponding values for 2000. The urban population stood at 11.32 million in 2010, which represented a 16.47% increase over that in 2000. The area affected by soil erosion in 2000 totaled 704,817 km², yet it had decreased to 674,135 km² by 2010. However, a path of modest urban development (rural-urban mitigation) and reasonable industrial structuring (the development of GDP-2) may partially reduce urbanization's ecological pressure and thus indirectly reduce the threat of soil erosion to human security. Therefore, to better control soil erosion in Inner Mongolia during the process of urbanization, the current model of economic development should be modified to improve the eco-efficiency of urbanization, while also promoting new modes of urbanization that are environmentally sustainable, cost-effective, and conserve limited resources.

An Assessment of the Impact of Urbanization on Soil Erosion in Inner Mongolia

PubMed Central

Xiao, Yi; Rao, En-Ming; Jiang, Ling; Xiao, Yang; Ouyang, Zhi-Yun

2018-01-01

Inner Mongolia, an autonomous region of the People’s Republic of China, has experienced severe soil erosion following a period of rapid economic development and urbanization. To investigate how urbanization has influenced the extent of soil erosion in Inner Mongolia, we used urbanization and soil erosion data from 2000 through 2010 to determine the relationship between urbanization and soil erosion patterns. Two empirical equations—the Revised Universal Soil Loss Equation (RUSLE) and the Revised Wind Erosion Equation (RWEQ)—were used to estimate the intensity of soil erosion, and we performed backward linear regression to model how it changed with greater urbanization. There was an apparent increase in the rate of urbanization and a decrease in the area affected by soil erosion in 2010 compared to the corresponding values for 2000. The urban population stood at 11.32 million in 2010, which represented a 16.47% increase over that in 2000. The area affected by soil erosion in 2000 totaled 704,817 km2, yet it had decreased to 674,135 km2 by 2010. However, a path of modest urban development (rural–urban mitigation) and reasonable industrial structuring (the development of GDP-2) may partially reduce urbanization’s ecological pressure and thus indirectly reduce the threat of soil erosion to human security. Therefore, to better control soil erosion in Inner Mongolia during the process of urbanization, the current model of economic development should be modified to improve the eco-efficiency of urbanization, while also promoting new modes of urbanization that are environmentally sustainable, cost-effective, and conserve limited resources. PMID:29562707

Contributions of solar-wind induced potential sputtering to the lunar surface erosion rate and it's exosphere

NASA Astrophysics Data System (ADS)

Alnussirat, S. T.; Barghouty, A. F.; Edmunson, J. E.; Sabra, M. S.; Rickman, D. L.

2018-04-01

Sputtering of lunar regolith by solar-wind protons and heavy ions with kinetic energies of about 1 keV/amu is an important erosive process that affects the lunar surface and exosphere. It plays an important role in changing the chemical composition and thickness of the surface layer, and in introducing material into the exosphere. Kinetic sputtering is well modeled and understood, but understanding of mechanisms of potential sputtering has lagged behind. In this study we differentiate the contributions of potential sputtering from the standard (kinetic) sputtering in changing the chemical composition and erosion rate of the lunar surface. Also we study the contribution of potential sputtering in developing the lunar exosphere. Our results show that potential sputtering enhances the total characteristic sputtering erosion rate by about 44%, and reduces sputtering time scales by the same amount. Potential sputtering also introduces more material into the lunar exosphere.

Post-fire land treatments and wind erosion -- lessons from the Milford Flat Fire, UT, USA

USGS Publications Warehouse

Miller, Mark E.; Bowker, Matthew A.; Reynolds, Richard L.; Goldstein, Harland L.

2012-01-01

We monitored sediment flux at 25 plots located at the northern end of the 2007 Milford Flat Fire (Lake Bonneville Basin, west-central Utah) to examine the effectiveness of post-fire rehabilitation treatments in mitigating risks of wind erosion during the first 3 years post fire. Maximum values were recorded during Mar–Jul 2009 when horizontal sediment fluxes measured with BSNE samplers ranged from 16.3 to 1251.0 g m−2 d−1 in unburned plots (n = 8; data represent averages of three sampler heights per plot), 35.2–555.3 g m−2 d−1 in burned plots that were not treated (n = 5), and 21.0–44,010.7 g m−2 d−1 in burned plots that received one or more rehabilitation treatments that disturbed the soil surface (n = 12). Fluxes during this period exhibited extreme spatial variability and were contingent on upwind landscape characteristics and surficial soil properties, with maximum fluxes recorded in settings downwind of treated areas with long treatment length and unstable fine sand. Nonlinear patterns of wind erosion attributable to soil and fetch effects highlight the profound importance of landscape setting and soil properties as spatial factors to be considered in evaluating risks of alternative post-fire rehabilitation strategies. By Mar–Jul 2010, average flux for all plots declined by 73.6% relative to the comparable 2009 period primarily due to the establishment and growth of exotic annual plants rather than seeded perennial plants. Results suggest that treatments in sensitive erosion-prone settings generally exacerbated rather than mitigated wind erosion during the first 3 years post fire, although long-term effects remain uncertain.

Evaluation of reanalysis near-surface winds over northern Africa in Boreal summer

NASA Astrophysics Data System (ADS)

Engelstaedter, Sebastian; Washington, Richard

2014-05-01

The emission of dust from desert surfaces depends on the combined effects of surface properties such as surface roughness, soil moisture, soil texture and particle size (erodibility) and wind speed (erosivity). In order for dust cycle models to realistically simulate dust emissions for the right reasons, it is essential that erosivity and erodibility controlling factors are represented correctly. There has been a focus on improving dust emission schemes or input fields of soil distribution and texture even though it has been shown that the use of wind fields from different reanalysis datasets to drive the same model can result in significant differences in the dust emissions. Here we evaluate the representation of near-surface wind speed from three different reanalysis datasets (ERA-Interim, CFSR and MERRA) over the North African domain. Reanalysis 10m wind speeds are compared with observations from SYNOP and METAR reports available from the UK Meteorological Office Integrated Data Archive System (MIDAS) Land and Marine Surface Stations Dataset. We compare 6-hourly observations of 10m wind speed between 1 January 1989 and 31 December 2009 from more the 500 surface stations with the corresponding reanalysis values. A station data based mean wind speed climatology for North Africa is presented. Overall, the representation of 10m winds is relatively poor in all three reanalysis datasets with stations in the northern parts of the Sahara still being better simulated (correlation coefficients ~ 0.5) than stations in the Sahel (correlation coefficients < 0.3) which points at the reanalyses not being able to realistically capture the Sahel dynamics systems. All three reanalyses have a systematic bias towards overestimating wind speed below 3-4 m/s and underestimating wind speed above 4 m/s. This bias becomes larger with increasing wind speed but is independent of the time of day. For instance, 14 m/s observed wind speeds are underestimated on average by 6 m/s in the ERA-Interim reanalysis. Given the cubic relationship between wind speed and dust emission this large underestimation is expected to significantly impact the simulation of dust emissions. A negative relationship between observed and ERA-Interim wind speed is found for winds above 14 m/s indicating that high wind speed generating processes are not well (if at all) represented in the model.

The impacts of grazing land management on the wind erodibility of the Mulga Lands of western Queensland, Australia

USDA-ARS?s Scientific Manuscript database

An estimated 100 Mt of dust is eroded by wind from the Australian land surface each year. Wind erosion may be widespread across the arid and semi-arid rangelands, with impacts on soil nutrients, carbon and ecosystem services, human health, and climate. The susceptibility of landscapes to wind erosio...

Wind tunnel studies of Martian aeolian processes

NASA Technical Reports Server (NTRS)

Greeley, R.; Iversen, J. D.; Pollack, J. B.; Udovich, N.; White, B.

1973-01-01

Preliminary results are reported of an investigation which involves wind tunnel simulations, geologic field studies, theoretical model studies, and analyses of Mariner 9 imagery. Threshold speed experiments were conducted for particles ranging in specific gravity from 1.3 to 11.35 and diameter from 10.2 micron to 1290 micron to verify and better define Bagnold's (1941) expressions for grain movement, particularly for low particle Reynolds numbers and to study the effects of aerodynamic lift and surface roughness. Wind tunnel simulations were conducted to determine the flow field over raised rim craters and associated zones of deposition and erosion. A horseshoe vortex forms around the crater, resulting in two axial velocity maxima in the lee of the crater which cause a zone of preferential erosion in the wake of the crater. Reverse flow direction occurs on the floor of the crater. The result is a distinct pattern of erosion and deposition which is similar to some martian craters and which indicates that some dark zones around Martian craters are erosional and some light zones are depositional.

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

Treesearch

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

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 ≤ 10 μm (PM10) established in the Clean Air Act. Agricultural straw has been widely used for rainfall-induced...

Take a Tumble: Weathering and Erosion Using a Rock Tumbler

ERIC Educational Resources Information Center

Coffey, Patrick; Mattox, Steve

2006-01-01

Weathering--the physical and chemical breakdown of geologic materials--and erosion--the transport of materials by wind, water, or ice--can be subtle, yet powerful forces. For example, shale, a rock made of mud-sized particles, is by far the most common sedimentary rock, a testament to the ability of weathering and erosion to take a rock and reduce…

Dust emission from wet and dry playas in the Mojave Desert, USA

USGS Publications Warehouse

Reynolds, R.L.; Yount, J.C.; Reheis, M.; Goldstein, H.; Chavez, P.; Fulton, R.; Whitney, J.; Fuller, C.; Forester, R.M.

2007-01-01

The interactions between playa hydrology and playa-surface sediments are important factors that control the type and amount of dust emitted from playas as a result of wind erosion. The production of evaporite minerals during evaporative loss of near-surface ground water results in both the creation and maintenance of several centimeters or more of loose sediment on and near the surfaces of wet playas. Observations that characterize the texture, mineralogic composition and hardness of playa surfaces at Franklin Lake, Soda Lake and West Cronese Lake playas in the Mojave Desert (California), along with imaging of dust emission using automated digital photography, indicate that these kinds of surface sediment are highly susceptible to dust emission. The surfaces of wet playas are dynamic - surface texture and sediment availability to wind erosion change rapidly, primarily in response to fluctuations in water-table depth, rainfall and rates of evaporation. In contrast, dry playas are characterized by ground water at depth. Consequently, dry playas commonly have hard surfaces that produce little or no dust if undisturbed except for transient silt and clay deposited on surfaces by wind and water. Although not the dominant type of global dust, salt-rich dusts from wet playas may be important with respect to radiative properties of dust plumes, atmospheric chemistry, windborne nutrients and human health.

Ice-Release and Erosion Resistant Materials for Wind Turbines

NASA Astrophysics Data System (ADS)

Zhang, Wei; Brinn, Cameron; Cook, Alex; Pascual-Marquez, Fernando

2017-11-01

Icing conditions may cause wind turbine generators to partially lose productivity or to be completely shut down to avoid structural damage. At present, commercially available technologies to mitigate this problem consist of expensive, energy hungry heating elements, which costs roughly 70,000 euro per medium size turbine. Conventional passive ice protection coating systems heavily rely on delicate surface structures and expensive materials to create water repellent superhydrophobic / low surface energy surfaces, which have been proven to be ineffective against ice accumulation. The lack of performance among conventional ice protection materials stems from a flaw in the approach to the problem: failure to recognize that water in its liquid form (WATER) and water in its solid form (ICE) are two different things. Something that works for WATER does not automatically work for ICE. Another reason is that many superhydrophobic materials are often reliant upon often fragile micro-structured surfaces to achieve their intended effects. This paper discusses a fundamentally different approach to the creation of a robust, low cost, durable, and multifunctional materials for ice release and erosion resistance. This National Science Foundation sponsored ice-release coating technology holds promise for protecting wind turbine blades and towers, thus potentially increasing reliability for power generation under icing conditions. Because of the vulnerability of wind turbine blades to ice buildup and erosion damages, wind farm facilities stand to reap considerable benefits.

Dynamics of volcanic ash remobilisation by wind through the Patagonian steppe after the eruption of Cordón Caulle, 2011

PubMed Central

Panebianco, Juan E.; Mendez, Mariano J.; Buschiazzo, Daniel E.; Bran, Donaldo; Gaitán, Juan J.

2017-01-01

Wind erosion of freshly-deposited volcanic ash causes persistent storms, strongly affecting ecosystems and human activity. Wind erosion of the volcanic ash was measured up to 17 months after the ash deposition, at 7 sites located within the ash-deposition area. The mass flux was measured up to 1.5 m above ground level. Mass transport rates were over 125 times the soil wind-erosion rates observed before the ash deposition, reaching up to 6.3 kg m−1 day−1. Total mass transport of ash during the 17 months ranged between 113.6 and 969.9 kg m−1 depending on topographic location and wind exposure. The vertical distribution of the mass flux at sites with higher vegetation cover was generally inverted as compared to sites with lower vegetation cover. This situation lasted 7 months and then a shift towards a more uniform vertical distribution was observed, in coincidence with the beginning of the decline of the mass transport rates. Decay rates differed between sites. Despite changes over time, an inverse linear correlation between the mass transports and the mass-flux gradients was found. Both the mass-flux gradients and the average mass-transport rates were not linked with shear-stress partition parameters, but with the ratio: ash-fall thickness to total vegetation cover. PMID:28349929

Dynamics of volcanic ash remobilisation by wind through the Patagonian steppe after the eruption of Cordón Caulle, 2011.

PubMed

Panebianco, Juan E; Mendez, Mariano J; Buschiazzo, Daniel E; Bran, Donaldo; Gaitán, Juan J

2017-03-28

Wind erosion of freshly-deposited volcanic ash causes persistent storms, strongly affecting ecosystems and human activity. Wind erosion of the volcanic ash was measured up to 17 months after the ash deposition, at 7 sites located within the ash-deposition area. The mass flux was measured up to 1.5 m above ground level. Mass transport rates were over 125 times the soil wind-erosion rates observed before the ash deposition, reaching up to 6.3 kg m -1 day -1 . Total mass transport of ash during the 17 months ranged between 113.6 and 969.9 kg m -1 depending on topographic location and wind exposure. The vertical distribution of the mass flux at sites with higher vegetation cover was generally inverted as compared to sites with lower vegetation cover. This situation lasted 7 months and then a shift towards a more uniform vertical distribution was observed, in coincidence with the beginning of the decline of the mass transport rates. Decay rates differed between sites. Despite changes over time, an inverse linear correlation between the mass transports and the mass-flux gradients was found. Both the mass-flux gradients and the average mass-transport rates were not linked with shear-stress partition parameters, but with the ratio: ash-fall thickness to total vegetation cover.

Erosion of mountain hiking trail over a seven-year period in Daisetsuzan National Park, central Hokkaido, Japan

Treesearch

Akemi Yoda; Teiji Watanabe

2000-01-01

Erosion of mountain hiking trails was investigated in Daisetsuzan National Park over a seven-year period. The amount and rate of erosion were different in the two typical landscape components. Cross-section diagrams revealed that trail depth became deeper in snowy vegetated areas than in wind-beaten bare ground areas. The existence and timing of runoff from snowmelt...

Characterizing effects of wind erosion on soil microtopography in a semiarid grassland using terrestrial laser scanning

NASA Astrophysics Data System (ADS)

Li, J.; Washington-Allen, R. A.; Okin, G. S.

2010-12-01

Aeolian processes play important roles in microtopography and associated soil-plant interactions in arid and semiarid landscapes. Most previous research has focused on scales larger than plant-interspaces and the dynamics of “fertile islands” associated with individual shrubs. Arid and semiarid ecosystems are notoriously heterogeneous in both microtopography and soil nutrients, and investigations of soil topography and plant-soil interactions at much finer scales (e.g., a few millimeters) are difficult using traditional point based sampling methods. Terrestrial laser scanners (TLS) are novel tools for which techniques can be developed to accurately characterize micro-scale topography with a spot diameter of 4.5 mm, and 2 mm ranging accuracy at 50 kHz. In this study, we employed a portable TLS (a Leica ScanStation 2) to digitally capture the 3-dimensional soil microtopography in a Chihuahuan desert grassland located in southern New Mexico. Soil surface on this site had been exposed to enhanced wind erosion since the spring of 2004. A control plot, located adjacent to the wind erosion plot, was also scanned to provide soil microtopography bench mark. A nearest neighbor interpolation was used on the elevation point clouds to yield bare ground, vegetation, and combined digital surface models for both plots. Additionally, measures of height and foliage diversity, vegetation and bare ground cover, and surface roughness were calculated. The results from this field study clearly demonstrate that TLS can provide insights on changes in microtopography affected by aeolian processes. Moreover, within the known distribution of soil nutrients, the 3D surface model of the soil microtopography provided unprecedented detail on the distribution of “mini” fertile islands associated with topography that were not revealed by studies at plant-interspace scale.

CLIGEN: Addressing deficiencies in the generator and its databases

USDA-ARS?s Scientific Manuscript database

CLIGEN is a stochastic generator that estimates daily temperatures, precipitation and other weather related phenomena. It is an intermediate model used by the Water Erosion Prediction Program (WEPP), the Wind Erosion Prediction System (WEPS), and other models that require daily weather observations....

Estimation of Annual Average Soil Loss, Based on Rusle Model in Kallar Watershed, Bhavani Basin, Tamil Nadu, India

NASA Astrophysics Data System (ADS)

Rahaman, S. Abdul; Aruchamy, S.; Jegankumar, R.; Ajeez, S. Abdul

2015-10-01

Soil erosion is a widespread environmental challenge faced in Kallar watershed nowadays. Erosion is defined as the movement of soil by water and wind, and it occurs in Kallar watershed under a wide range of land uses. Erosion by water can be dramatic during storm events, resulting in wash-outs and gullies. It can also be insidious, occurring as sheet and rill erosion during heavy rains. Most of the soil lost by water erosion is by the processes of sheet and rill erosion. Land degradation and subsequent soil erosion and sedimentation play a significant role in impairing water resources within sub watersheds, watersheds and basins. Using conventional methods to assess soil erosion risk is expensive and time consuming. A comprehensive methodology that integrates Remote sensing and Geographic Information Systems (GIS), coupled with the use of an empirical model (Revised Universal Soil Loss Equation- RUSLE) to assess risk, can identify and assess soil erosion potential and estimate the value of soil loss. GIS data layers including, rainfall erosivity (R), soil erodability (K), slope length and steepness (LS), cover management (C) and conservation practice (P) factors were computed to determine their effects on average annual soil loss in the study area. The final map of annual soil erosion shows a maximum soil loss of 398.58 t/ h-1/ y-1. Based on the result soil erosion was classified in to soil erosion severity map with five classes, very low, low, moderate, high and critical respectively. Further RUSLE factors has been broken into two categories, soil erosion susceptibility (A=RKLS), and soil erosion hazard (A=RKLSCP) have been computed. It is understood that functions of C and P are factors that can be controlled and thus can greatly reduce soil loss through management and conservational measures.

Development and validation of a method to estimate the potential wind erosion risk in Germany

NASA Astrophysics Data System (ADS)

Funk, Roger; Deumlich, Detlef; Völker, Lidia

2017-04-01

The introduction of the Cross Compliance (CC) regulations for soil protection resulted in the demand for the classification of the the wind erosion risk on agricultural areas in Germany nationwide. A spatial highly resolved method was needed based on uniform data sets and validation principles, which provides a fair and equivalent procedure for all affected farmers. A GIS-procedure was developed, which derives the site specific wind erosion risk from the main influencing factors: soil texture, wind velocity, wind direction and landscape structure following the German standard DIN 19706. The procedure enables different approaches in the Federal States and comparable classification results. Here, we present the approach of the Federal State of Brandenburg. In the first step a complete soil data map was composed in a grid size of 10 x 10 m. Data were taken from 1.) the Soil quality Appraisal (scale 1:10.000), 2.) the Medium-scale Soil Mapping (MMK, 1:25.000), 3.) extrapolating the MMK, 4.) new Soil quality Appraisal (new areas after coal-mining). Based on the texture and carbon content the wind erosion susceptibility was divided in 6 classes. This map was combined with data of the annual average wind velocity resulting in an increase of the risk classes for wind velocities > 5 ms-1 and a decrease for < 3 ms-1. The sheltering effect of landscape structure is regarded by allocating a height to each landscape element, corresponding to the described features in the digital "Biotope and Land Use Map". The "hill shade" procedure of ArcGIS was used to set virtual shadows behind the landscape elements for eight directions. The relative frequency of wind from each direction was used as a weighting factor and multiplied with the numerical values of the shadowed cells. Depending on the distance to the landscape element the shadowing effect was combined with the risk classes. The results show that the wind erosion risk is obviously reduced by integrating landscape structures into the risk assessment. After the renewed classification for the entire Federal State, about 60% of the area in the highest, and 40% in the medium risk classes changed into lower classes. The area of the highest potential risk class decreased from 40% to 17% in relation to the total area. A validation of this approach was made by data of the Digital Surface Model (DSM, first pulse) from laser scanning of an area of 144 km2 with a spatial resolution of 1 x 1 m. It could be shown that the allocated height values of the landscape elements were correct in 75% per cent, too low in 15% and too high in 11% off all cases. The current landscape element map of the Federal State of Brandenburg will be replaced, when the DSM is available for the entire area in the near future.

Wind Erosion

NASA Image and Video Library

2015-07-02

Long term winds have etched the surface in Memnonia Sulci. Partial cemented surface materials are easily eroded by the wind, forming linear ridges called yardangs. The multiple direction of yardangs in this VIS image indicate that there were at least two different wind directions in this area. Orbit Number: 59217 Latitude: -8.33112 Longitude: 186.506 Instrument: VIS Captured: 2015-04-20 15:12 http://photojournal.jpl.nasa.gov/catalog/PIA19502

High-Voltage Isolation Transformer

NASA Technical Reports Server (NTRS)

Clatterbuck, C. H.; Ruitberg, A. P.

1985-01-01

Arcing and field-included surface erosion reduced by electrostatic shields around windings and ferromagnetic core of 80-kilovolt isolation transformer. Fabricated from high-resistivity polyurethane-based material brushed on critical surfaces, shields maintained at approximately half potential difference of windings.

Integrating WEPP into the WEPS infrastructure

USDA-ARS?s Scientific Manuscript database

The Wind Erosion Prediction System (WEPS) and the Water Erosion Prediction Project (WEPP) share a common modeling philosophy, that of moving away from primarily empirically based models based on indices or "average conditions", and toward a more process based approach which can be evaluated using ac...

Pyrosequencing reveals bacteria carried in different wind-eroded sediments.

PubMed

Gardner, Terrence; Acosta-Martinez, Veronica; Calderón, Francisco J; Zobeck, Ted M; Baddock, Matthew; Van Pelt, R Scott; Senwo, Zachary; Dowd, Scot; Cox, Stephen

2012-01-01

Little is known about the microbial communities carried in wind-eroded sediments from various soil types and land management systems. The novel technique of pyrosequencing promises to expand our understanding of the microbial diversity of soils and eroded sediments because it can sequence 10 to 100 times more DNA fragments than previous techniques, providing enhanced exploration into what microbes are being lost from soil due to wind erosion. Our study evaluated the bacterial diversity of two types of wind-eroded sediments collected from three different organic-rich soils in Michigan using a portable field wind tunnel. The wind-eroded sediments evaluated were a coarse sized fraction with 66% of particles >106 μm (coarse eroded sediment) and a finer eroded sediment with 72% of particles <106 μm. Our findings suggested that (i) bacteria carried in the coarser sediment and fine dust were effective fingerprints of the source soil, although their distribution may vary depending on the soil characteristics because certain bacteria may be more protected in soil surfaces than others; (ii) coarser wind-eroded sediment showed higher bacterial diversity than fine dust in two of the three soils evaluated; and (iii) certain bacteria were more predominant in fine dust (, , and ) than coarse sediment ( and ), revealing different locations and niches of bacteria in soil, which, depending on wind erosion processes, can have important implications on the soil sustainability and functioning. Infrared spectroscopy showed that wind erosion preferentially removes particular kinds of C from the soil that are lost via fine dust. Our study shows that eroded sediments remove the active labile organic soil particulates containing key microorganisms involved in soil biogeochemical processes, which can have a negative impact on the quality and functioning of the source soil. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Validation of SWEEP for creep, saltation, and suspension in a desert-oasis ecotone

NASA Astrophysics Data System (ADS)

Pi, H.; Sharratt, B.; Feng, G.; Lei, J.; Li, X.; Zheng, Z.

2016-03-01

Wind erosion in the desert-oasis ecotone can accelerate desertification, but little is known about the susceptibility of the ecotone to wind erosion in the Tarim Basin despite being a major source of windblown dust in China. The objective of this study was to test the performance of the Single-event Wind Erosion Evaluation Program (SWEEP) in simulating soil loss as creep, saltation, and suspension in a desert-oasis ecotone. Creep, saltation, and suspension were measured and simulated in a desert-oasis ecotone of the Tarim Basin during discrete periods of high winds in spring 2012 and 2013. The model appeared to adequately simulate total soil loss (ranged from 23 to 2272 g m-2 across sample periods) according to the high index of agreement (d = 0.76). The adequate agreement of the SWEEP in simulating total soil loss was due to the good performance of the model (d = 0.71) in simulating creep plus saltation. The SWEEP model, however, inadequately simulated suspension based upon a low d (⩽0.43). The slope estimates of the regression between simulated and measured suspension and difference of mean suggested that the SWEEP underestimated suspension. The adequate simulation of creep plus saltation thus provides reasonable estimates of total soil loss using SWEEP in a desert-oasis environment.

[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 0.925 Pa, respectively.

The Effect on Soil Erosion of Different Tillage Applications

NASA Astrophysics Data System (ADS)

Gür, Kazım

2016-04-01

The Effects on Soil Erosion of Different Tillage Applications Kazım Gür1, Kazim Çarman2 and Wim M.Cornelis3 1Bahri Daǧdaş International Agricultural Research Instıtute, 42020 Konya, Turkey 2Faculty of Agriculture, Department of Agricultural Machinery, University of Selçuk, 42031 Konya, Turkey 3Department of Soil Management, Faculty of Bioscience Engineering, Ghent University, 653 Coupure Links, 9000 Gent, Belgium Traditional soil cultivation systems, with excessive and inappropriate soil tillage, will generally lead to soil degradation and loss of soil by wind erosion. Continuous reduced tillage and no-till maintaining soil cover with plant residues called Conservation Agriculture that is considered as effective in reducing erosion. There exist a wide variety of practices using different tools that comply with reduced tillage principles. However, few studies have compared the effect of several of such tools in reducing wind erosion and related soil and surface properties. We therefore measured sediment transport rates over bare soil surfaces (but with under stubbles of wheat, Triticum aestivum L.) subjected to three tillage practices using two pulling type machines and one type of power takeoff movable machines and generated with a portable field wind tunnel. At 10 ms-1, sediment transport rates varied from 107 to 573 gm-1h-1, and from 176 to 768 gm-1h-1 at 13 ms-1. The lowest transport rates were observed for N(no-tillage) and the highest for Rr(L-type rototiller). After tillage, surface roughness, mean weighted diameter, wind erodible fraction, mechanical stability and soil water content were measured as well and varied from 5.0 to 15.9%, 6.9 to 13.8 mm, 14.3 to 29.7%, 79.5 to 93.4% and 8.6 to 15.1%, respectively, with again N is being the most successful practice. In terms of conservation soil tillage technique, it can be said that the applications compared with each other; direct sowing machine is more appropriate and cause to the less erosion.

7 CFR 610.11 - Purpose and scope.

Code of Federal Regulations, 2012 CFR

2012-01-01

... AGRICULTURE CONSERVATION OPERATIONS TECHNICAL ASSISTANCE Soil Erosion Prediction Equations § 610.11 Purpose... by the Natural Resources Conservation Service (NRCS) to predict soil erosion due to water and wind... Act, as amended, 16 U.S.C. 3801-3813 specified that the Secretary would publish the universal soil...

7 CFR 610.11 - Purpose and scope.

Code of Federal Regulations, 2013 CFR

2013-01-01

... AGRICULTURE CONSERVATION OPERATIONS TECHNICAL ASSISTANCE Soil Erosion Prediction Equations § 610.11 Purpose... by the Natural Resources Conservation Service (NRCS) to predict soil erosion due to water and wind... Act, as amended, 16 U.S.C. 3801-3813 specified that the Secretary would publish the universal soil...

7 CFR 610.11 - Purpose and scope.

Code of Federal Regulations, 2010 CFR

2010-01-01

... AGRICULTURE CONSERVATION OPERATIONS TECHNICAL ASSISTANCE Soil Erosion Prediction Equations § 610.11 Purpose... by the Natural Resources Conservation Service (NRCS) to predict soil erosion due to water and wind... Act, as amended, 16 U.S.C. 3801-3813 specified that the Secretary would publish the universal soil...

7 CFR 610.11 - Purpose and scope.

Code of Federal Regulations, 2011 CFR

2011-01-01

... AGRICULTURE CONSERVATION OPERATIONS TECHNICAL ASSISTANCE Soil Erosion Prediction Equations § 610.11 Purpose... by the Natural Resources Conservation Service (NRCS) to predict soil erosion due to water and wind... Act, as amended, 16 U.S.C. 3801-3813 specified that the Secretary would publish the universal soil...

7 CFR 610.11 - Purpose and scope.

Code of Federal Regulations, 2014 CFR

2014-01-01

... AGRICULTURE CONSERVATION OPERATIONS TECHNICAL ASSISTANCE Soil Erosion Prediction Equations § 610.11 Purpose... by the Natural Resources Conservation Service (NRCS) to predict soil erosion due to water and wind... Act, as amended, 16 U.S.C. 3801-3813 specified that the Secretary would publish the universal soil...

Monitoring Soil Erosion of a Burn Site in the Central Basin and Range Ecoregion: Final Report on Measurements at the Gleason Fire Site, Nevada

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

Miller, Julianne; Etyemezian, Vicken; Shillito, Rose

The increase in wildfires in arid and semi-arid parts of Nevada and elsewhere in the southwestern United States has implications for post-closure management and long-term stewardship for Soil Corrective Action Units (CAUs) on the Nevada National Security Site (NNSS) for which the Nevada Field Office of the United States Department of Energy, National Nuclear Security Administration has responsibility. For many CAUs and Corrective Action Sites, where closure-in-place alternatives are now being implemented or considered, there is a chance that these sites could burn over at some time while they still pose a risk to the environment or human health, givenmore » the long half lives of some of the radionuclide contaminants. This study was initiated to examine the effects and duration of wildfire on wind and water erodibility on sites analogous to those that exist on the NNSS. The data analyzed herein were gathered at the prescribed Gleason Fire site near Ely, Nevada, a site comparable to the northern portion of the NNSS. Quantification of wind erosion was conducted with a Portable In-Situ Wind ERosion Lab (PI-SWERL) on unburned soils, and on interspace and plant understory soils within the burned area. The PI-SWERL was used to estimate emissions of suspendible particles (particulate matter with aerodynamic diameters less than or equal to 10 micrometers) at different wind speeds. Filter samples, collected from the exhaust of the PI-SWERL during measurements, were analyzed for chemical composition. Based on nearly three years of data, the Gleason Fire site does not appear to have returned to pre burn wind erosion levels. Chemical composition data of suspendible particles are variable and show a trend toward pre-burn levels, but provide little insight into how the composition has been changing over time since the fire. Soil, runoff, and sediment data were collected from the Gleason Fire site to monitor the water erosion potential over the nearly three-year period. Soil hydrophobicity (water repellency) was noted on burned understory soils up to 12 months after the fire, as was the presence of ash on the soil surface. Soil deteriorated from a strong, definable pre-fire structure to a weakly cohesive mass (unstructured soil) immediately after the fire. Surface soil structure was evident 34 months after the fire at both burned and unburned sites, but was rare and weaker at burned sites. The amount of runoff and sediment was highly variable, but runoff occurred more frequently at burned interspace sites compared to burned understory and unburned interspace sites up to 34 months after the burn. No discernible pattern was evident on the amount of sediment transported, but the size of sediment from burned understory sites was almost double that of burned and unburned interspace soils after the fire, and decreased over the monitoring period. Curve numbers, a measure of the runoff potential, did not indicate any obvious runoff response to the fire. However, slight seasonal changes in curve numbers and runoff potential and, therefore, post-fire runoff response may be a function of fire impacts as well as the time of year that precipitation occurs. Site (interspace or understory) differences in soil properties and runoff persisted even after the fire. Vegetation data showed the presence of invasive grasses after the fire. Results from analysis of wind and water coupled with the spatial analysis of vegetation suggest that wind erosion may continue to occur due to the additional exposed soil surface (burned understory sites) until vegetation becomes re-established, and runoff may occur more frequently in interspace sites. The potential for fire-related wind erosion and water erosion may persist beyond three years in this system.« less

The Potential of Wetlands in Reducing Storm Surge

DTIC Science & Technology

2010-01-01

threatened by erosion and damage due to storm waves, wind, and surge. The risk of damage and loss of life is exacerbated by many factors, including coastal...obtained when attempting to correlate hurricane translation speed, surge hydrograph at the coast, and surge elevations inland. However, a trend was...greater surface roughness. In addition to reducing wind speeds, the models eliminate the wind stress in forested wetlands which inhibit wind from

77 FR 36871 - Endangered and Threatened Wildlife and Plants; Withdrawal of the Proposed Rule To List Dunes...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-19

... shinnery oak community. During the late Pleistocene era, wind erosion of the Blackwater Draw formation along with shinnery oak encroachment formed this unique dune system. The prevailing winds blow from the... spatially dynamic system that is altered by natural processes like wind and rain. Over time, these natural...

Sediment grain-size characteristics and relevant correlations to the aeolian environment in China's eastern desert region.

PubMed

Zhang, Chunlai; Shen, Yaping; Li, Qing; Jia, Wenru; Li, Jiao; Wang, Xuesong

2018-06-15

To identify characteristics of aeolian activity and the aeolian environment in China's eastern desert region, this study collected surface sediment samples from the main desert and sandy lands in this region: the Hobq Desert and the Mu Us, Otindag, Horqin, and Hulunbuir sandy lands. We analyzed the grain-size characteristics and their relationships to three key environmental indicators: drift potential, the dune mobility index, and vegetation cover. The main sediment components are fine to medium sands, with poor (Hulunbuir) to moderate (all other areas) sorting, of unimodal to bimodal distribution. This suggests that improved sorting is accomplished by the loss of both relatively coarser and finer grains. Since 2000, China's eastern desert region has generally experienced low wind energy environmental conditions, resulting in decreased dune activity. In the Hobq Desert, however, the dry climate and sparse vegetation, in conjunction with the most widely distributed mobile dune area in the eastern desert region, have led to frequent and intense aeolian activity, including wind erosion, sand transport, and deposition, resulting in conditions for good sediment sorting. In the Mu Us, Otindag, and Horqin sandy lands, mosaic distribution has resulted from wind erosion-dominated and deposition-dominated aeolian environments. In the Hulunbuir Sandy Land, high precipitation, low temperatures, and steppe vegetation have resulted in well-developed soils; however, strong winds and flat terrain have created an aeolian environment dominated by wind erosion. Copyright © 2018. Published by Elsevier B.V.

Visualizing and quantifying microtopographic change of dryland landscapes from an unmanned aircraft system

USDA-ARS?s Scientific Manuscript database

Background/Question/Methods: Soil and site stability are key attributes of assessing the health of dryland landscapes because these lands are susceptible to high rates of wind- and water-caused erosion. Field techniques for measuring and monitoring soil erosion in drylands are often labor intensive...

Threshold friction velocity of crusted windblown soils in the Columbia Plateau

USDA-ARS?s Scientific Manuscript database

Wind erosion processes are governed by soil physical properties and surface characteristics. Erosion is initiated when the friction velocity exceeds the threshold friction velocity (u*t) of soils. Although u*t is influenced by soil physical properties such as wetness and crusting, there is little in...

Wind-Driven Erosion and Exposure Potential at Mars 2020 Rover Candidate-Landing Sites.

PubMed

Chojnacki, Matthew; Banks, Maria; Urso, Anna

2018-02-01

Aeolian processes have likely been the predominant geomorphic agent for most of Mars' history and have the potential to produce relatively young exposure ages for geologic units. Thus, identifying local evidence for aeolian erosion is highly relevant to the selection of landing sites for future missions, such as the Mars 2020 Rover mission that aims to explore astrobiologically relevant ancient environments. Here we investigate wind-driven activity at eight Mars 2020 candidate-landing sites to constrain erosion potential at these locations. To demonstrate our methods, we found that contemporary dune-derived abrasion rates were in agreement with rover-derived exhumation rates at Gale crater and could be employed elsewhere. The Holden crater candidate site was interpreted to have low contemporary erosion rates, based on the presence of a thick sand coverage of static ripples. Active ripples at the Eberswalde and southwest Melas sites may account for local erosion and the dearth of small craters. Moderate-flux regional dunes near Mawrth Vallis were deemed unrepresentative of the candidate site, which is interpreted to currently be experiencing low levels of erosion. The Nili Fossae site displayed the most unambiguous evidence for local sand transport and erosion, likely yielding relatively young exposure ages. The downselected Jezero crater and northeast Syrtis sites had high-flux neighboring dunes and exhibited substantial evidence for sediment pathways across their ellipses. Both sites had relatively high estimated abrasion rates, which would yield young exposure ages. The downselected Columbia Hills site lacked evidence for sand movement, and contemporary local erosion rates are estimated to be relatively low.

Wind-Driven Erosion and Exposure Potential at Mars 2020 Rover Candidate-Landing Sites

PubMed Central

Chojnacki, Matthew; Banks, Maria; Urso, Anna

2018-01-01

Aeolian processes have likely been the predominant geomorphic agent for most of Mars’ history and have the potential to produce relatively young exposure ages for geologic units. Thus, identifying local evidence for aeolian erosion is highly relevant to the selection of landing sites for future missions, such as the Mars 2020 Rover mission that aims to explore astrobiologically relevant ancient environments. Here we investigate wind-driven activity at eight Mars 2020 candidate-landing sites to constrain erosion potential at these locations. To demonstrate our methods, we found that contemporary dune-derived abrasion rates were in agreement with rover-derived exhumation rates at Gale crater and could be employed elsewhere. The Holden crater candidate site was interpreted to have low contemporary erosion rates, based on the presence of a thick sand coverage of static ripples. Active ripples at the Eberswalde and southwest Melas sites may account for local erosion and the dearth of small craters. Moderate-flux regional dunes near Mawrth Vallis were deemed unrepresentative of the candidate site, which is interpreted to currently be experiencing low levels of erosion. The Nili Fossae site displayed the most unambiguous evidence for local sand transport and erosion, likely yielding relatively young exposure ages. The downselected Jezero crater and northeast Syrtis sites had high-flux neighboring dunes and exhibited substantial evidence for sediment pathways across their ellipses. Both sites had relatively high estimated abrasion rates, which would yield young exposure ages. The downselected Columbia Hills site lacked evidence for sand movement, and contemporary local erosion rates are estimated to be relatively low. PMID:29568719

Wind-Driven Erosion and Exposure Potential at Mars 2020 Rover Candidate-Landing Sites

NASA Astrophysics Data System (ADS)

Chojnacki, Matthew; Banks, Maria; Urso, Anna

2018-02-01

Aeolian processes have likely been the predominant geomorphic agent for most of Mars' history and have the potential to produce relatively young exposure ages for geologic units. Thus, identifying local evidence for aeolian erosion is highly relevant to the selection of landing sites for future missions, such as the Mars 2020 Rover mission that aims to explore astrobiologically relevant ancient environments. Here we investigate wind-driven activity at eight Mars 2020 candidate-landing sites to constrain erosion potential at these locations. To demonstrate our methods, we found that contemporary dune-derived abrasion rates were in agreement with rover-derived exhumation rates at Gale crater and could be employed elsewhere. The Holden crater candidate site was interpreted to have low contemporary erosion rates, based on the presence of a thick sand coverage of static ripples. Active ripples at the Eberswalde and southwest Melas sites may account for local erosion and the dearth of small craters. Moderate-flux regional dunes near Mawrth Vallis were deemed unrepresentative of the candidate site, which is interpreted to currently be experiencing low levels of erosion. The Nili Fossae site displayed the most unambiguous evidence for local sand transport and erosion, likely yielding relatively young exposure ages. The downselected Jezero crater and northeast Syrtis sites had high-flux neighboring dunes and exhibited substantial evidence for sediment pathways across their ellipses. Both sites had relatively high estimated abrasion rates, which would yield young exposure ages. The downselected Columbia Hills site lacked evidence for sand movement, and contemporary local erosion rates are estimated to be relatively low.

RECONSTRUCTING THE SOLAR WIND FROM ITS EARLY HISTORY TO CURRENT EPOCH

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

Airapetian, Vladimir S.; Usmanov, Arcadi V., E-mail: vladimir.airapetian@nasa.gov, E-mail: avusmanov@gmail.com

Stellar winds from active solar-type stars can play a crucial role in removal of stellar angular momentum and erosion of planetary atmospheres. However, major wind properties except for mass-loss rates cannot be directly derived from observations. We employed a three-dimensional magnetohydrodynamic Alfvén wave driven solar wind model, ALF3D, to reconstruct the solar wind parameters including the mass-loss rate, terminal velocity, and wind temperature at 0.7, 2, and 4.65 Gyr. Our model treats the wind thermal electrons, protons, and pickup protons as separate fluids and incorporates turbulence transport, eddy viscosity, turbulent resistivity, and turbulent heating to properly describe proton and electronmore » temperatures of the solar wind. To study the evolution of the solar wind, we specified three input model parameters, the plasma density, Alfvén wave amplitude, and the strength of the dipole magnetic field at the wind base for each of three solar wind evolution models that are consistent with observational constrains. Our model results show that the velocity of the paleo solar wind was twice as fast, ∼50 times denser and 2 times hotter at 1 AU in the Sun's early history at 0.7 Gyr. The theoretical calculations of mass-loss rate appear to be in agreement with the empirically derived values for stars of various ages. These results can provide realistic constraints for wind dynamic pressures on magnetospheres of (exo)planets around the young Sun and other active stars, which is crucial in realistic assessment of the Joule heating of their ionospheres and corresponding effects of atmospheric erosion.« less

Temporal and spatial variation of maximum wind speed days during the past 20 years in major cities of Xinjiang

NASA Astrophysics Data System (ADS)

Baidourela, Aliya; Jing, Zhen; Zhayimu, Kahaer; Abulaiti, Adili; Ubuli, Hakezi

2018-04-01

Wind erosion and sandstorms occur in the neighborhood of exposed dust sources. Wind erosion and desertification increase the frequency of dust storms, deteriorate air quality, and damage the ecological environment and agricultural production. The Xinjiang region has a relatively fragile ecological environment. Therefore, the study of the characteristics of maximum wind speed and wind direction in this region is of great significance to disaster prevention and mitigation, the management of activated dunes, and the sustainable development of the region. Based on the latest data of 71 sites in Xinjiang, this study explores the temporal evolution and spatial distribution of maximum wind speed in Xinjiang from 1993 to 2013, and highlights the distribution of annual and monthly maximum wind speed and the characteristics of wind direction in Xinjiang. Between 1993 and 2013, Ulugchat County exhibited the highest number of days with the maximum wind speed (> 17 m/s), while Wutian exhibited the lowest number. In Xinjiang, 1999 showed the highest number of maximum wind speed days (257 days), while 2013 showed the lowest number (69 days). Spring and summer wind speeds were greater than those in autumn and winter. There were obvious differences in the direction of maximum wind speed in major cities and counties of Xinjiang. East of the Tianshan Mountains, maximum wind speeds are mainly directed southeast and northeast. North and south of the Tianshan Mountains, they are mainly directed northwest and northeast, while west of the Tianshan Mountains, they are mainly directed southeast and northwest.

Wind erodibility response of physical and biological crusts to rain and flooding

NASA Astrophysics Data System (ADS)

Aubault, H.; Bullard, J. E.; Strong, C. L.; Ghadiri, H.; McTainsh, G. H.

2015-12-01

Soil surface crusts are important controllers of the small-scale wind entrainment processes that occur across all dust source regions globally. The crust type influences water and wind erosion by impacting infiltration, runoff, threshold wind velocity and surface storage capacity of both water and loose erodible material. The spatial and temporal patterning of both physical and biological crusts is known to change with rainfall and flooding. However, little is known about the impact of differing water quantity (from light rainfall through to flooding) on soil crusting characteristics (strength, roughness, sediment loss). This study compares the response of two soil types (loamy sand - LS, sandy loam - SL) with and without BSCs to three different rainfall events (2mm, 8mm, 15mm). Two BSC treatments were used one that simulated a young cyanobacteria dominated crust and an older flood induced multi species biological crust. For both soil types, soil surface strength increased with increasing rainfall amount with LS having consistently higher resistance to rupture than SL. Regardless of texture, soils with BSCs were more resistant and strength did not change in response to rainfall impact. Soil loss due to wind erosion was substantially higher on bare LS (4 times higher) and SL (3 times higher) soils compared with those with BSCs. Our results also show that young biological crust (formed by the rainfall event) have reduced soil erodibility with notably greater strength, roughness and reduced sediment losses when compared to soils with physical crust. Interestingly though, the erodibility of the old BSC did not differ greatly from that of the young BSC with respect to strength, roughness and sediment loss. This raises questions regarding the rapid soil surface protection offered by young colonising cyanobacteria crusts. Further analyses exploring the role of biological soil crusts on surface response to rainfall and wind saltation impact are ongoing.

Wind erosion as an environmental transport pathway of glyphosate and AMPA

NASA Astrophysics Data System (ADS)

Bento, Célia P. M.; Goossens, Dirk; Rezaei, Mahrooz; Riksen, Michel; Mol, Hans G. J.; Ritsema, Coen J.; Geissen, Violette

2017-04-01

Glyphosate is the active ingredient of many commercial formulations of herbicides extensively used worldwide for weed control. Because glyphosate and its main metabolite aminomethylphosphonic acid (AMPA) are considered non-volatile, their loss to the atmosphere is considered negligible. Both compounds strongly adsorb to soil particles and wind-eroded sediment and dust are thus a possible environmental transport pathway. This can result in environmental and human exposure far beyond the agricultural areas where it has been applied. Therefore, special attention is required to the airborne transport of glyphosate and AMPA. In this study, we investigated the behavior of glyphosate and AMPA in wind-eroded sediment by measuring their content in different size fractions (median diameters between 715 and 8 µm) of a loess soil, during a period of 28 days after glyphosate application. Granulometrical extraction was done using a wind tunnel and a Soil Fine Particle Extractor. Extractions were conducted on days 0, 3, 7, 14, 21 and 28 after glyphosate application. Results indicated that glyphosate and AMPA contents were significantly higher in the finest particle fractions (median diameters between 8 and 18 µm), and lowered significantly with the increase in particle size. Glyphosate and AMPA contents correlated positively with clay, organic matter, and silt content. The dissipation of glyphosate over time was very low, which was associated to the low soil moisture content of the sediment. Consequently, the formation of AMPA was also very low. The low dissipation of glyphosate in our study indicates that the risk of glyphosate transport in dry sediment to off-target areas by wind can be very high. The highest glyphosate and AMPA contents were found in the smallest soil fractions (PM10 and less), which are easily inhaled. This contributes to the risk of human and animal exposure and, therefore, more attention should be paid to this route of exposure in environmental and human health risk assessment studies. Moreover, glyphosate applications during dry periods in regions susceptible to wind erosion should be avoided.

Determination of soil degradation in argentine semi-arid environments from remote sensors: case department of patagones, province of buenos aires

NASA Astrophysics Data System (ADS)

Pezzola, Alejandro; Cacella, Alejandra; Enrique, Mario; Winschel, Cristina

2017-04-01

The continental territory of the Argentine Republic owns 75% of its surface under arid and semiarid conditions to the west of the meridian of 64°. Wind erosion is the main physical cause of desertification. In the Pampena area, studies showed that the sandy loam soils were more pronounced than the sandy loam with significant losses of organic matter, decreases in the cation exchange capacity and modification of the mineral composition of the very fine sand fraction (From 73 to 100 μm), with increases in the proportion of heavy minerals (magnetite) relative to light (quartz). In the Patagones department, Buenos Aires province, the soils with a sandy-loamy texture, which are transported by wind and deposited on calcium carbonate (tosca), with little moisture retention and susceptible to wind erosion. In the 1980s and 1990s, increases in rainfall above the historical average led to a shift of the isohytes towards the southwest, leading to agricultural intensification that caused greater pressure on the soil and native vegetation. This advance on the native vegetation within the Patagones produced a reduction between 1975 and 2009 of 432,280 ha, leaving only 31% of the area covered by native forest - shrub xerophyte today. Between 2005-2009, the call "agricultural drought" caused losses in crops, wheat - oats and natural pastures associated with the native forest, causing a significant deterioration of the soil, exposing them to wind erosion. Remote sensors represent a very valuable technology for the mapping and evaluation of soil erosion. The availability of multispectral images allows the mapping and monitoring of changes in the dynamics of the erosion process. The objective of this work was to make an expeditious diagnosis of the surface affected by wind erosion and to evaluate the degree to which the soils destined for agriculture and livestock were affected. For this purpose, Terra's MODIS (Moderate-Resolution Imaging Spectroradiometer) sensor information was used with a temporal resolution of 1 to 2 days, 36 spectral bands, spatial resolution of 250m and Improved Vegetation Index (EVI). The period was covered from July 2007 to July 2009 by analyzing 47 images of the EVI product. The phenological curves of the soil cover were obtained. Of 1,360,717 ha it was estimated that there are a total of 393,511 hectares of eroded soils: 47,337 ha from mild to moderate, 219,204 ha moderate to severe and 126,970 ha severe to severe

The role of carbon dust emission as a global source of atmospheric CO2

USDA-ARS?s Scientific Manuscript database

Soil erosion redistributes soil organic carbon (SOC) within terrestrial ecosystems, to the atmosphere and oceans. Dust export is an essential component of the carbon (C) and carbon dioxide (CO2) budget, because wind erosion contributes to the C cycle by selectively removing4 SOC from vast areas and ...

30 CFR 717.18 - Dams constructed of or impounding waste material.

Code of Federal Regulations, 2012 CFR

2012-07-01

... at least 3 feet to avoid overtopping by wind and wave action. (iii) Dams shall have minimum safety... pressures, internal erosion, sloughing, removal of material by solution, or erosion of material by loss into... regulatory authority before construction begins. (8) All dams shall be removed and the disturbed areas...

30 CFR 717.18 - Dams constructed of or impounding waste material.

Code of Federal Regulations, 2014 CFR

2014-07-01

... at least 3 feet to avoid overtopping by wind and wave action. (iii) Dams shall have minimum safety... pressures, internal erosion, sloughing, removal of material by solution, or erosion of material by loss into... regulatory authority before construction begins. (8) All dams shall be removed and the disturbed areas...

30 CFR 717.18 - Dams constructed of or impounding waste material.

Code of Federal Regulations, 2013 CFR

2013-07-01

... at least 3 feet to avoid overtopping by wind and wave action. (iii) Dams shall have minimum safety... pressures, internal erosion, sloughing, removal of material by solution, or erosion of material by loss into... regulatory authority before construction begins. (8) All dams shall be removed and the disturbed areas...

Soil organic carbon dust emission: an omitted global source of atmospheric CO2?

USDA-ARS?s Scientific Manuscript database

Soil erosion redistributes soil organic carbon (SOC) within terrestrial ecosystems, to the atmosphere and oceans. Dust export is an essential component of the carbon (C) and carbon dioxide (CO2) budget because wind erosion contributes to the C cycle by removing selectively SOC from vast areas and tr...

Soil degradation in India: Challenges and potential solutions

USDA-ARS?s Scientific Manuscript database

Soil degradation in India is estimated to occur on 147 Mha of land, including 94 Mha from water erosion, 16 Mha from acidification, 14 Mha from flooding, 9 Mha from wind erosion, 6 Mha from salinity, and 7 Mha from a combination of factors. India supports 18% of the world’s human population and 15%...

Yardangs near Olympus Mons

NASA Image and Video Library

2002-12-16

In this region of the Olympus Mons aureole, located to the SW of the volcano, the surface has been eroded by the wind into linear landforms called yardangs. These ridges generally point in direction of the prevailing winds that carved them, in this case winds from the southeast. Yardangs typically occur on surfaces that are easily erodable, such as wind-blown dust or volcanic ash. The northeast - southwest trending ridges and valleys in the northwest corner of the image are typical of the Olympus Mons aureole. The varying concentration and shape of the yardangs in this area may be controlled by the motion of winds around these topographic features. Some crater outlines are visible near the top of this image. The rims of these craters appear to have been stripped away - indicating that the wind erosion is younger than these craters. There are two round knobs in the image, one on the bottom on the right side of the image and another about midway down on the left. These may be inverted craters, formed because the impacts caused materials underneath the crater to become harder to erode than the surrounding materials. http://photojournal.jpl.nasa.gov/catalog/PIA04036

Representation of Vegetation and Other Nonerodible Elements in Aeolian Shear Stress Partitioning Models for Predicting Transport Threshold

NASA Technical Reports Server (NTRS)

King, James; Nickling, William G.; Gillies, John A.

2005-01-01

The presence of nonerodible elements is well understood to be a reducing factor for soil erosion by wind, but the limits of its protection of the surface and erosion threshold prediction are complicated by the varying geometry, spatial organization, and density of the elements. The predictive capabilities of the most recent models for estimating wind driven particle fluxes are reduced because of the poor representation of the effectiveness of vegetation to reduce wind erosion. Two approaches have been taken to account for roughness effects on sediment transport thresholds. Marticorena and Bergametti (1995) in their dust emission model parameterize the effect of roughness on threshold with the assumption that there is a relationship between roughness density and the aerodynamic roughness length of a surface. Raupach et al. (1993) offer a different approach based on physical modeling of wake development behind individual roughness elements and the partition of the surface stress and the total stress over a roughened surface. A comparison between the models shows the partitioning approach to be a good framework to explain the effect of roughness on entrainment of sediment by wind. Both models provided very good agreement for wind tunnel experiments using solid objects on a nonerodible surface. However, the Marticorena and Bergametti (1995) approach displays a scaling dependency when the difference between the roughness length of the surface and the overall roughness length is too great, while the Raupach et al. (1993) model's predictions perform better owing to the incorporation of the roughness geometry and the alterations to the flow they can cause.

Anthropogenic radionuclides for estimating rates of soil redistribution by wind

USDA-ARS?s Scientific Manuscript database

Erosion of soil by wind and water is a degrading process that affects millions of hectares worldwide. Atmospheric testing of nuclear weapons and the resulting fallout of anthropogenic radioisotopes, particularly Cesium 137, has made possible the estimation of mean soil redistribution rates. The pe...

Anthropogenic radioisotopes to estimate rates of soil redistribution by wind

USDA-ARS?s Scientific Manuscript database

Erosion of soil by wind and water is a degrading process that affects millions of hectares worldwide. Atmospheric testing of nuclear weapons and the resulting fallout of anthropogenic radioisotopes, particularly Cesium 137, has made possible the estimation of mean soil redistribution rates. The pe...

Agriculture’s Soil Conservation Programs Miss Full Potential in the Fight against Soil Erosion.

DTIC Science & Technology

1983-11-28

Soil Loss Equation ( USLE ) and Wind Erosion Equation can be used with a reasonable degree of accuracy. It is the intention of ASCS to expand VC/SL to...HD-R37 495 AGRICULTURE’S SOIL CONSERVATION PROGRAMS MISS FULL i/i POTENTIAL IN THE FIGHT.(U) GENERAL ACCOUNTING OFFICE WASHINGTON DC RESOURCES...GENERAL Report To The Congress OF THE UNITED STATES Agriculture’s Soil Conservation Programs Miss Full Potential In The Fight Against Soil Erosion

Application of the Gillette model for windblown dust at Owens Lake, CA

NASA Astrophysics Data System (ADS)

Ono, Duane

Windblown dust can have significant impacts on local air pollution levels, and in cases such as dust from Africa or Asia, can have global impacts on our environment. Models to estimate particulate matter emissions from windblown dust are generally based on the local wind speed, the threshold wind speed to initiate erosion, and the soil texture of a given surface. However, precipitation, soil crusting, and soil disturbance can dramatically change the threshold wind speed and erosion potential of a surface, making modeling difficult. A low-cost sampling and analysis method was developed to account for these surface changes in a wind erosion model. Windblown dust emissions measured as PM 10 (particulate matter less than a nominal 10 μm aerodynamic diameter) have been found to be generally proportional to sand flux (also known as saltation flux). In this study, a model was used to estimate sand flux using the relationship Q=AρG/g, where Q is horizontal sand flux, A is a surface erosion potential factor, ρ is air density, g is the gravitational constant, and G=∫ u*(u*2-u*t2)dt, where u* is friction velocity and u is the threshold friction velocity of the surface. The variable A in the model was derived by comparing the measured sand flux for a given period and area to G for the same period. Sand flux was monitored at Owens Lake, CA using low-cost Cox Sand Catchers (CSCs) for monthly measurements, and more expensive electronic sensors (Sensits) to measure hourly flux rates and u. Monitors were spaced 1 km apart at 114 sites, covering one clay and three sand-dominated soil areas. Good model results relied primarily on the erosion potential A, which could be determined from CSC measurements and wind speed data. Annual values for A were found to range from 1.3 to 3.5 in the three sand areas. The value of A was an order of magnitude lower (0.2) in the less erodible clay area. Previous studies showed similar values for A of 0.7 and 2.9 for a sandy site at Owens Lake, and 1.1 for a site in the Chihuahuan desert in New Mexico. The model performed well using annual values for A and better with monthly values, with R2 ranging from 0.74 to 0.87 for hourly sand flux rates in the four study areas. Monthly changes in A accounted for temporal surface changes, such as precipitation and surface crusting in the model predictions. This study demonstrated that low-cost periodic sand flux sampling using CSCs can provide a practical method to determine values for A in a simple wind erosion model, and that this model can provide good hourly and monthly estimates of sand flux rates in windblown dust areas.

A Workshop on Desert Processes, September 24-28, 1984- Report on the Conference,

DTIC Science & Technology

1987-01-01

W12 *j2 ll .. m11116’ w 1.25 *IM.4 1. 6 MICROCOPY RESOLUTION TEST CHART NATIONAL BUREAU OF SIANOAROS-1963-A , / i9 Z- - ;im... ... i U.S. GEOLOGICAL...Winds Department of Agriculture (USDA) Wind Erosion Laboratory, and D.A. Gillette, National J.F. McCauley, C.S. Breed, P.J. Helm. Oceanic and...protected area on of wind as a geologic agent. public land west of White Sands National Measurements of wind speeds (including peak Monument, New

Modifying landscape connectivity by reducing wind driven sediment redistribution, northern Chihuahuan Desert, USA

USDA-ARS?s Scientific Manuscript database

Shrub encroachment into perennial grasslands is occurring in many arid and semi-arid parts of the world. As shrubs displace perennial grasslands, bare patches coalesce to enhance soil erosion and sediment fluxes by wind and water transport. Reducing the connectedness of these sediment transport path...

Wind erosion of cropland in the northwestern Tarim Basin

USDA-ARS?s Scientific Manuscript database

The Aksu region within the Tarim Basin is a major source of windblown dust due to aridity and vast areas under intensive irrigated crop production. Despite the importance of crop production to the local economy and sustenance, little is known about the amount of soil eroded by wind from agricultural...

A COMBINED MODELING AND MEASUREMENT TECHNIQUE FOR ESTIMATING WIND-BLOWN DUST EMISSIONS AT OWENS (DRY) LAKE, CA

EPA Science Inventory

A refined method of modeling atmospheric dust concentrations due to wind erosion was developed using real-time saltation flux measurements and ambient dust monitoring data at Owens Lake, California. This modeling method may have practical applications for modeling the atmospheric...

Chemical composition of windblown dust emitted from agricultural soils amended with biosolids

USDA-ARS?s Scientific Manuscript database

Biosolids are increasingly being applied to agricultural lands in dry environments, but wind erosion of these lands might transport biosolid particulates offsite and impact environmental quality. Our objective was to use a wind tunnel to measure soil and windblown sediment concentrations of EPA-regu...

Dust-associated microbiomes from dryland wheat fields differ with tillage practice and biosolids application

NASA Astrophysics Data System (ADS)

Schlatter, Daniel C.; Schillinger, William F.; Bary, Andy I.; Sharratt, Brenton; Paulitz, Timothy C.

2018-07-01

Wind erosion is a significant threat to the productivity and sustainability of agricultural soils. In the dryland winter wheat (Triticum aestivum L.)-fallow region of Inland Pacific Northwest of the USA (PNW), farmers increasingly use conservation tillage practices to control wind erosion. In addition, some farmers in this dry region apply municipal biosolids to soils as fertilizer and a source of stable organic matter. The impacts of soil management practices on emissions of dust microbiota to the atmosphere are understudied. We used high-throughput DNA sequencing to examine the impacts of conservation tillage and biosolids amendments on the transport of dust-associated fungal and bacterial communities during simulated high-wind events over two years at Lind, WA. The fungal and bacterial communities contained in windblown dust differed significantly with tillage (conservation vs. conventional) and fertilizer (synthetic vs. biosolids) treatments. However, the richness and diversity of fungal and bacterial communities of dust did not vary significantly with tillage or fertilizer treatments. Taxa enriched in dust from fields under conservation tillage represented many plant-associated taxa that likely grow on residue left on the soil surface, whereas taxa that were more abundant with conventional tillage were those that likely grow on buried plant residue. Dust from biosolids-amended fields harbored greater abundances of taxa that likely feed on introduced carbon. Most human-associated taxa that may pose a health risk were not present in dust after biosolids amendment, although members of Clostridiaceae were enriched with this treatment. Results show that tillage and fertilizer management practices impact the composition of bioaerosols emitted during high-wind events and have potential implications for plant and human health.

Quantifying Hillslope to Watershed Erosional Response Following Wildfire

NASA Astrophysics Data System (ADS)

Vega, S.; Pierson, F. B.; Williams, C. J.; Brooks, E. S.; Pierce, J. L.; Roehner, C.

2016-12-01

The frequency and severity of wildfires is increasing across western US sagebrush steppe rangelands as the result of warming climate conditions and invasive plant species. Following wildfire, the soil surface is left with little vegetation, exposing it to erosion by wind and water. Erosion following wildfires is a concern among land managers due to the threat it poses to resources, infrastructure, and human health. Most post-fire erosion research has used artificial rainfall. This study uses natural rainfall and a network of silt fences to quantify hillslope to watershed scale erosion response following the 2015 Soda Fire that burned 113,300 ha in southwestern Idaho and southeastern Oregon. In this study, we will evaluate the drivers of erosion over multiple spatial scales and assess the recovery of vegetation and soil water repellency for a two year period post-fire. We installed a network of silt fences over long and short hillslope distances and in swales within a 130 ha catchment within the Reynolds Creek Experimental Watershed in southwestern Idaho, USA. The overall study design consists of thirty silt fences spanning north and south facing aspects, an existing weir measuring watershed streamflow and sediment discharge, and two meteorological stations. The erosional response following the fire was mainly driven by wind and snowmelt. The swales produced the most sediment compared to the long and short hillslopes. On the south facing aspect the long and short hillslopes did not produce any sediment whereas on the north facing aspect the swales produced the most sediment. This presentation summarizes these preliminary first year hydrologic and erosion responses. The results provide data for determining the drivers for erosion at different spatial scales, advance understanding of post-fire hillslope to watershed erosional responses, and offer insight into recovery of vegetation and soil water repellency post-fire. This study will aid land management agencies throughout the western US with predicting post-fire erosion responses as well as determining appropriate erosion mitigation strategies.

Aeolian responses to climate variability during the past century on Mesquite Lake Playa, Mojave Desert

USGS Publications Warehouse

Whitney, John W.; Breit, George N.; Buckingham, S.E.; Reynolds, Richard L.; Bogle, Rian C.; Luo, Lifeng; Goldstein, Harland L.; Vogel, John M.

2015-01-01

The erosion and deposition of sediments by wind from 1901 to 2013 have created large changes in surface features of Mesquite Lake playa in the Mojave Desert. The decadal scale recurrence of sand-sheet development, migration, and merging with older dunes appears related to decadal climatic changes of drought and wetness as recorded in the precipitation history of the Mojave Desert, complemented by modeled soil-moisture index values. Historical aerial photographs, repeat land photographs, and satellite images document the presence and northward migration of a mid-20th century sand sheet that formed during a severe regional drought that coincided with a multi-decadal cool phase of the Pacific Decadal Oscillation (PDO). The sand sheet slowly eroded during the wetter conditions of the subsequent PDO warm phase (1977–1998) due to a lack of added sediment. Sand cohesion gradually increased in the sand sheet by seasonal additions of salt and clay and by re-precipitation of gypsum, which resulted in the wind-carving of yardangs in the receding sand sheet. Smaller yardangs were aerodynamically shaped from coppice dunes with salt-clay crusts, and larger yardangs were carved along the walls and floor of trough blowouts. Evidence of a 19th century cycle of sand-sheet formation and erosion is indicated by remnants of yardangs, photographed in 1901 and 1916, that were found buried in the mid-20th century sand sheet. Three years of erosion measurements on the playa, yardangs, and sand sheets document relatively rapid wind erosion. The playa has lowered 20 to 40 cm since the mid-20th century and a shallow deflation basin has developed since 1999. Annually, 5–10 cm of surface sediment was removed from yardang flanks by a combination of wind abrasion, deflation, and mass movement. The most effective erosional processes are wind stripping of thin crusts that form on the yardang surfaces after rain events and the slumping of sediment blocks from yardang flanks. These wind-eroded landforms persist several decades to a century before eroding away or being buried by younger sands. On Mesquite Lake playa the climatic history of alternating PDO phases of multi-decadal drought and wetness is recorded twice by the presence of yardangs formed nearly a century apart.

Wave and Beach Processes Modeling for Sabine Pass to Galveston Bay, Texas, Shoreline Erosion Feasibility Study

DTIC Science & Technology

2007-08-01

local wind field , led to the development of an appropriate alternative procedure which produced GENESIS results in agreement with observations...River field site wave data. ........................................................................................................53 Table 17...been abandoned since 1989 due to shoreline erosion. From east to west, the inlets in the study area include Sabine Pass, Rollover Pass near the

Patchiness in wind erosion-deposition patterns in response to a recent state change reversal in the Chihuahuan Desert

USDA-ARS?s Scientific Manuscript database

Shifts from shrub-dominated states to grasslands are believed to be irreversible as a result of positive feedbacks between woody plants and soil properties. In the Chihuahuan Desert, mesquite (Prosopis glandulosa) expansion into black grama (Bouteloua eriopoda) grasslands is maintained by wind redis...

Sediment and PM10 flux from no-tillage cropping systems in the Pacific Northwest

USDA-ARS?s Scientific Manuscript database

Wind erosion is a concern in the Inland Pacific Northwest (PNW) United States where the emission of fine particulates from winter wheat – summer fallow (WW/SF) dryland cropping systems during high winds degrade air quality. Although no-tillage cropping systems are not yet economically viable, these ...

Distribution of glyphosate and aminomethylphosphonic acid (AMPA) in agricultural topsoils of the European Union.

PubMed

Silva, Vera; Montanarella, Luca; Jones, Arwyn; Fernández-Ugalde, Oihane; Mol, Hans G J; Ritsema, Coen J; Geissen, Violette

2018-04-15

Approval for glyphosate-based herbicides in the European Union (EU) is under intense debate due to concern about their effects on the environment and human health. The occurrence of glyphosate residues in European water bodies is rather well documented whereas only few, fragmented and outdated information is available for European soils. We provide the first large-scale assessment of distribution (occurrence and concentrations) of glyphosate and its main metabolite aminomethylphosphonic acid (AMPA) in EU agricultural topsoils, and estimate their potential spreading by wind and water erosion. Glyphosate and/or AMPA were present in 45% of the topsoils collected, originating from eleven countries and six crop systems, with a maximum concentration of 2mgkg -1 . Several glyphosate and AMPA hotspots were identified across the EU. Soil loss rates (obtained from recently derived European maps) were used to estimate the potential export of glyphosate and AMPA by wind and water erosion. The estimated exports, result of a conceptually simple model, clearly indicate that particulate transport can contribute to human and environmental exposure to herbicide residues. Residue threshold values in soils are urgently needed to define potential risks for soil health and off site effects related to export by wind and water erosion. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Medusae Fossae Formation

NASA Technical Reports Server (NTRS)

2002-01-01

(Released 16 April 2002) The Science This THEMIS visible image was acquired near 11o N, 159o W (201o E) and shows examples of the remarkable variations that can be seen in the erosion of the Medusae Fossae Formation. This Formation is a soft, easily eroded deposit that extends for nearly 1,000 km along the equator of Mars. In this region, like many others throughout the Medusae Fossae Formation, the surface has been eroded by the wind into a series of linear ridges called yardangs. These ridges generally point in direction of the prevailing winds that carved them, and demonstrate the power of martian winds to erode the landscape of Mars. The easily eroded nature of the Medusae Fossae Formation suggests that it is composed of weakly cemented particles, and was most likely formed by the deposition of wind-blown dust or volcanic ash. Within this single image it is possible to see differing amounts of erosion and stripping of layers in the Medusae Fossae Formation. Near the bottom (southern) edge of the image a rock layer with a relatively smooth upper surface covers much of the image. Moving upwards (north) in the image this layer becomes more and more eroded. At first there are isolated regions where the smooth unit has been eroded to produce sets of parallel ridges and knobs. Further north these linear knobs increase in number, and only small, isolated patches of the smooth upper surface remain. Finally, at the top of the image, even the ridges have been removed, exposing the remarkably smooth top of hard, resistant layer below. This sequence of layers with differing hardness and resistance to erosion is common on Earth and on Mars, and suggests significant variations in the physical properties, composition, particle size, and/or cementation of these martian layers. As is common throughout the Medusae Fossae Formation, very few impact craters are visible, indicating that the surface exposed is relatively young, and that the process of erosion may be active today. The Story 'Yardang!' Now, that may seem like a peculiar-sounding curse word, but nobody would get in trouble for using it. A yardang is one of the very cool-sounding words geologists use to describe long, irregular features like the ones seen in this image. Yardangs are grooved, furrowed ridges that form as the wind erodes away weakly cemented material in the region. Rippling across the surface, yardangs tell the story of how the powerful Martian wind carved the surface into such a gorgeous pattern over time. (Don't miss clicking on the above image to see a detailed view, in which the beauty and almost dance-like symmetry of the waving terrain pops out in highly compelling, three-dimensional texture.) It may be easy to see which way the wind blows in this area, since these streamlined features point in the direction of prevailing winds. But how can geologists understand the various kinds of terrain seen here? First, they have to study the different patterns of erosion, looking closely at how the wind has stripped off certain layers and not others. Want to be a geologist yourself? Start at the bottom of the image and scroll upward, and see how the relatively smooth, higher terrain toward the south gradually becomes more and more eroded. Moving up the image, at first you?ll see only a few, isolated regions of parallel ridges and knolls. Go a little farther north with your eyes (toward the center of the image), and you?ll see how these linear knobs really get going! Once you get to the top of the image, only patches of these grooved ridges remain, leaving an incredibly smooth, wind-scrubbed surface behind. You know this layer has to be made of pretty hard material, because it seems impervious to further erosion. Geologists studying Mars can compare these Martian yardangs to examples found on Earth, such as those in the Lut desert of Iran. Humans have even been known to use the wind as their inspiration, sculpting the shape of yardangs themselves. The famous sphynx at Giza in Egypt is thought to be a yardang that's been whittled down a little more by ancient human chiselers.

A method to estimate wind turbine blade damage and to design damage-resilient blades

NASA Astrophysics Data System (ADS)

Fiore, Giovanni

Wind turbine blades are affected by continuous impacts with airborne particles that deteriorate the blade surface and yield to a drop in output power. Based on the climatic conditions and geographic locations of a given wind farm, multiple types of particles are observed in air. The present study focuses on simulating the impact of four types of particles, namely insects, sand grains, hailstones, and rain drops with the blade surface. A numerical inviscid flowfield code, coupled with a particle position predictor code was used. Upon impact, the damaging effect to the blade surface was evaluated. Each type of particle was associated with a damage mode, which depends on the mass, size, and hardness of the particle. It was found that insects strike and adhere to the blade in a region close to the leading edge. On the other hand, it was seen that sand grains promote erosion just downstream of the leading edge, where local velocity reaches a maximum and the impact angle is shallow. Moreover, particles such as rain drops are associated with fatigue and erosion at the very leading edge and on the upper side of the blade section. Finally, hailstones promote delamination and fatigue in the composite panels of the blade surface. Photographic evidence of damaged blade surfaces was used in the present research as a comparison with the simulations performed for various types of particle and different initial conditions. Based on such observations, a theorization of the damage pattern and evolution was proposed. Finally, given a set of well-established blade section geometries, such as the Delft University and NREL S airfoil families, a comparison of airfoil damage fitness was proposed and possible means of shape optimization were discussed. The investigation of blade geometry features to mitigate damage was performed. Based on previous results, it was argued that a viable blade section optimization may be performed for the lightest and smallest particles considered in the study, the sand grains. A pool of airfoils was analyzed regarding the sand erosion rate. It was shown that a bulbous leading edge coupled with airfoil aft camber is beneficial toward the erosion rate due to sand grains. An optimization algorithm was written to improve the damage resilience toward sand erosion of wind turbine airfoils. A direct and inverse approach were integrated in a genetic algorithm code, and it was confirmed that bulbous leading edges, coupled with aft cambers allowed for a reduction in blade erosion rates. Lastly, a time-stepping code was developed to predict the blade section geometry when sand erosion is present. It was found that three main phases occur during the erosive life of a blade. A parametric study allowed to find the most relevant drivers to the blade lifespan with respect to erosion. Beneficial effects come from an increase in turbine hub height, turbine rated power, increase in lift coefficient, and a reduction in average particle diameter. A parametric study was also performed by investigating different airfoil geometries. Again, it was found that bulbous leading edges coupled with aft cambered geometries allow for longer blade lifespan.

Field and laboratory comparison of PM10 instruments in high winds

NASA Astrophysics Data System (ADS)

Sharratt, Brenton; Pi, Huawei

2018-06-01

Instruments capable of measuring PM10 (particulate matter ≤10 μm in aerodynamic diameter) concentrations may vary in performance as a result of different technologies utilized in measuring PM10. Therefore, the performance of five instruments capable of measuring PM10 concentrations above eroding soil surfaces was tested during high wind events at field sites in the Columbia Plateau and inside a wind tunnel. Comparisons among the Big Spring Number Eight (BSNE) sampler, DustTrak monitor, E-sampler, High-Volume sampler, and Tapered Element Oscillating Microbalance (TEOM) monitor were made at field sites during nine wind erosion events and inside a wind tunnel at two wind speeds (7 and 12 m s-1) and two ambient PM10 concentrations (2 and 50 mg m-3). PM10 concentrations were similar for the High-Volume sampler and TEOM monitor as well as for the BSNE samplers and DustTrak monitors but higher for the High-Volume sampler and TEOM monitor than the E-sampler during field erosion events. Based upon wind tunnel experiments, the TEOM monitor measured the highest PM10 concentration while the DustTrak monitor typically measured the lowest PM10 concentration as compared with other instruments. In addition, PM10 concentration appeared to lower for all instruments at a wind speed of 12 as compared with 7 m s-1 inside the wind tunnel. Differences in the performance of instruments in measuring PM10 concentration poses risks in comparing PM10 concentration among different instrument types or using multiple instrument types to jointly measure concentrations in the field or laboratory or even the same instrument type subject to different wind speeds.

The Role of Windbreaks in Reducing Water Resources Use in Irrigated Agriculture

NASA Astrophysics Data System (ADS)

Cochrane, T. A.; de Vries, T. T.

2014-12-01

Windbreaks are common features in flat agricultural landscapes around the world. The reduction in wind speed afforded by windbreaks is dictated by their porosity, location, height, and distance from the windbreak. The reduction in wind speeds not only reduces potential wind erosion; it also reduces crop evapotranspiration (ET) and provides shelter for livestock and crops. In the Canterbury plains of New Zealand there are over 300,000 km of windbreaks which were first implemented as a soil conservation strategy to reduce wind erosion of prime agricultural land. Agriculture in the region has since changed to irrigated pasture cultivation for dairy production and windbreaks are being cut down or reduced to heights of 2 m to allow for large scale centre-pivot irrigation schemes. Although soil erosion is no longer a major concern due to permanent pasture cover, irrigation water is sourced from limited supplies of ground and surface water and thus the effects of wind on irrigation losses due to spray drift and increased ET are of significant concern. The impact of reducing windbreaks needs to be understood in terms of water resources use. Experimental and theoretical work was conducted to quantify the reduction in wind speeds by windbreaks and in spray evaporation losses. A temporal and spatial model was also developed and validated to quantify the impact of single and multiple windbreaks on irrigation water losses. Initial modelling results show that for hot windy dry conditions in Canterbury, ET can increase by up to 1.4 mm/day when windbreaks are reduced to 2 m in height and on average wind days ET can increase by up to 0.5 mm/day. ET can be reduced by up to 30% in the windbreak leeward zone relative to ET in areas not protected by windbreaks. Wind speed, air temperature and relative humidity all had a considerable impact on spray evaporation losses, but the extent is determined by the droplet size. Estimated losses range from only 0.07% to 67% for 5 and 0.2 mm droplet sizes respectively. Preliminary measurements of typical irrigation spray nozzles with a range of drop sizes show losses of up to 30% under high wind conditions. Potential reduction in ground and surface water resources use for irrigation can be significant if windbreaks are maintained by using irrigation systems that can be adapted to work within windbreaks.

A quantitative analysis of rock cliff erosion environments

NASA Astrophysics Data System (ADS)

Lim, M.; Rosser, N.; Petley, D. N.; Norman, E. C.; Barlow, J.

2009-12-01

The spatial patterns and temporal sequencing of failures from coastal rock cliffs are complex and typically generate weak correlations with environmental variables such as tidal inundation, wave energy, wind and rain. Consequently, understanding of rock cliff behaviour, its response to predicted changes in environmental forcing and, more specifically, the interaction between marine and climatic factors in influencing failure processes has remained limited. This work presents the results from the first attempt to characterise and quantify the conditions on coastal cliffs that lead to accelerated rates of material detachment. The rate of change in an 80 m high section of coastal rock cliffs has been surveyed annually with high-resolution terrestrial laser scanning (TLS). The rockfall data have been analysed according to a simplified source geology that exhibit distinct magnitude-frequency distributions relating to the dominance of particular failure types. An integrated network of sensors and instrumentation designed to reflect the lithological control on failure has been installed to examine both the distinction between prevailing conditions and those affecting the local cliff environment and the physical response of different rock types to micro-climatic processes. The monitoring system records near-surface rock strain, temperature, moisture and micro-seismic displacement in addition to air temperature, humidity, radiation, precipitation, water-level and three-dimensional wind characteristics. A characteristic environmental signal, unique to the cliff face material, has been identified that differs substantially from that experienced by the surrounding area; suggesting that established methods of meteorological and tidal data collection are insufficient and inappropriate to represent erosive processes. The interaction between thermo- and hydro-dynamics of the cliff environment and the physical response of the rock highlights the composite environmental effects acting on the rock mass and provides a new interpretation on the dominant controls on the behaviour of coastal rock cliffs that challenges the almost universal application of undercutting and cantilever collapse as the primary driver of rock cliff erosion.

Linking playa surface dust emission potential to feedbacks between surface moisture and salt crust expansion through high resolution terrestrial laser scanning measurements

NASA Astrophysics Data System (ADS)

Nield, J. M.; King, J.; Wiggs, G.

2012-12-01

The dust emissivity of salt pans (or playas) can be significant but is controlled by interactions between wind erosivity, surface moisture, salt chemistry and crust morphology. These surface properties influence the aeolian transport threshold and can be highly variable over both short temporal and spatial scales. In the past, field studies have been hampered by practical difficulties in accurately measuring properties controlling sediment availability at the surface in high resolution. Studies typically therefore, have investigated large scale monthly or seasonal change using remote sensing and assume a homogeneous surface when predicting dust emissivity. Here we present the first high resolution measurements (sub-cm) of salt crust expansion related to changes in diurnal moisture over daily and weekly time periods using terrestrial laser scanning (TLS, ground-based LiDAR) on Sua Pan, Botswana. The TLS measures both elevation and relative surface moisture change simultaneously, without disturbing the surface. Measurement sequences enable the variability in aeolian sediment availability to be quantified along with temporal feedbacks associated with crust degradation. On crusts with well-developed polygon ridges (high aerodynamic and surface roughness), daily surface expansion was greater than 30mm. The greatest surface change occurred overnight on the upper, exposed sections of the ridges, particularly when surface temperatures dropping below 10°C. These areas also experienced the greatest moisture variation and became increasingly moist overnight in response to an increase in relative humidity. In contrast, during daylight hours, the ridge areas were drier than the lower lying inter-ridge areas. Positive feedbacks between surface topography and moisture reinforced the maximum diurnal moisture variation at ridge peaks, encouraging crust thrusting due to overnight salt hydration, further enhancing the surface, and therefore, aerodynamic roughness. These feedbacks between surface roughness and moisture have implications for dust emissivity because crust expansion increases fluff production which is one of the main dust source materials. Further, increased roughness can locally increase wind erosivity and the potential evaporation of ridge areas. Crust thrusting also weakens the ridge peaks, developing cracked surfaces and exposing the sediment supply source below. These fast acting processes can have a major influence on wind erosion variability and dust emissivity from key dust source regions.; a-d) Elevation change overnight. e-f) Elevation change over 6 days.

Controls on wind abrasion patterns through a fractured bedrock landscape

NASA Astrophysics Data System (ADS)

Perkins, J. P.; Finnegan, N. J.

2017-12-01

Wind abrasion is an important geomorphic process for understanding arid landscape evolution on Earth and interpreting the post-fluvial history of Mars. Both the presence and orientation of wind-abraded landforms provide potentially important constraints on paleo-climatic conditions; however, such interpretations can be complicated by lithologic and structural heterogeneity. To explore the influence of pre-existing structure on wind abrasion, we exploit a natural experiment along the 10.2 Ma Lower Rio San Pedro ignimbrite in northern Chile. Here, a 3.2 Ma andesite flow erupted from Cerro de las Cuevas and deposited atop the ignimbrite, supplying wind-transportable sediment and initiating a phase of downwind abrasion. Additionally, the lava flow provides a continually varying degree of upwind topographic shielding along the ignimbrite that is reflected in a range of surface morphologies. Where fully shielded the ignimbrite surface is partially blanketed by sediment. However, as relief decreases the surface morphology shifts from large polygonal structures that emerge due to the concentration of wind abrasion along pre-existing fracture sets, to polygons that are bisected by wind-parallel grooves that cross-cut fracture sets, to linear sets of yardangs. We reconstruct the ignimbrite surface using a high-resolution digital elevation model, and calculate erosion rates ranging from 0.002 to 0.45 mm/kyr that vary strongly with degree of topographic shielding (R2 = 0.97). We use measured abrasion rates together with nearby weather station data to estimate the nondimensional Rouse number and Inertial Parameter for a range of particle sizes. From these calculations, we hypothesize that the change from fracture-controlled to flow-controlled morphology reflects increases in the grain size and inertia of particles in the suspension cloud. Where the ignimbrite experiences persistent high winds, large particles may travel in suspension and are largely insensitive to topographic steering. Conversely, smaller particles, which comprise the bulk of wind-transported material in lower velocity settings, can be fully deflected along fracture paths. Wind-abraded landforms therefore likely reflect a competition between the material skeleton of the landscape and the strength of the flow that shapes it.

Crop residue harvest impacts wind erodibility and simulated loss in the Central Great Plains

USDA-ARS?s Scientific Manuscript database

Crop residue removal can affect the susceptibility of soil loss on wind erosion-prone soils such as those of the central Great Plains, US. Six on-farm trials conducted from 2011 to 2013 in Kansas determined the effects of winter wheat (Triticum aestivum L.), corn (Zea mays L.), and grain sorghum (So...

Incorporating the Wind Erosion Prediction System (WEPS) Into a Regional Air Quality Modeling System for the Pacific Northwest

USDA-ARS?s Scientific Manuscript database

In the Pacific Northwest, wind storms intermittently cause massive dust events that reduce visibility along roadways and jeopardize health as a result of extremely high concentrations of PM10 (particulate matter less than or equal to 10µm in diameter). An early warning dust forecast system is needed...

30 CFR 762.5 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... dunes, severe wind or soil erosion, frequent flooding, avalanches and areas of unstable geology...-handling, preparation, extraction or storage facilities, and other capital-intensive activities. Costs of...

30 CFR 762.5 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... dunes, severe wind or soil erosion, frequent flooding, avalanches and areas of unstable geology...-handling, preparation, extraction or storage facilities, and other capital-intensive activities. Costs of...

30 CFR 762.5 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... dunes, severe wind or soil erosion, frequent flooding, avalanches and areas of unstable geology...-handling, preparation, extraction or storage facilities, and other capital-intensive activities. Costs of...

Monitoring Soil Erosion on a Burned Site in the Mojave-Great Basin Transition Zone: Final Report for the Jacob Fire Site

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

Miller, Julianne; Etyemezian, Vic; Cablk, Mary E.

A historic return interval of 100 years for large fires in the U.S. southwestern deserts is being replaced by one where fires may reoccur as frequently as every 20 to 30 years. The shortened return interval, which translates to an increase in fires, has implications for management of Soil Corrective Action Units (CAUs) and Corrective Action Sites (CASs) for which the Department of Energy, National Nuclear Security Administration Nevada Field Office has responsibility. A series of studies was initiated at uncontaminated analog sites to better understand the possible impacts of erosion and transport by wind and water should contaminated soilmore » sites burn. The first of these studies was undertaken at the Jacob Fire site approximately 12 kilometers (7.5 miles) north of Hiko, Nevada. A lightning-caused fire burned approximately 200 hectares during August 6-8, 2008. The site is representative of a transition between Mojave and Great Basin desert ecoregions on the Nevada National Security Site (NNSS), where the largest number of Soil CAUs/CASs are located. The area that burned at the Jacob Fire site was primarily a Coleogyne ramosissima (blackbrush) and Ephedra nevadensis (Mormon tea) community, also an abundant shrub assemblage in the similar transition zone on the NNSS. This report summarizes three years of measurements after the fire. Seven measurement campaigns at the Jacob Fire site were completed. Measurements were made on burned ridge (upland) and drainage sites, and on burned and unburned sites beneath and between vegetation. A Portable In-Situ Wind Erosion Lab (PI-SWERL) was used to estimate emissions of suspended particles at different wind speeds. Context for these measurements was provided through a meteorological tower that was installed at the Jacob Fire site to obtain local, relevant environmental parameters. Filter samples, collected from the exhaust of the PI-SWERL during measurements, were analyzed for chemical composition. Runoff and water erosion were quantified through a series of rainfall/runoff simulation tests in which controlled amounts of water were delivered to the soil surface in a specified amount of time. Runoff data were collected from understory and interspace soils on burned ridge and drainage areas. Runoff volume and suspended sediment in the runoff were sampled; the particle size distribution of the sediment was determined by laboratory analysis. Several land surface and soil characteristics associated with runoff were integrated by the calculation of site-specific curve numbers. Several vegetation surveys were conducted to assess post-burn recovery. Data from plots in both burned and unburned areas included species identification, counts, and location. Characterization of fire-affected area included measures at both the landscape scale and at specific sites. Although wind erosion measurements indicate that there are seasonal influences on almost all parameters measured, several trends were observed. PI-SWERL measurements indicated the potential for PM10 windblown dust emissions was higher on areas that were burned compared to areas that were not. Among the burned areas, understory soils in drainage areas were the most emissive, and interspace soils along burned ridges were least emissive. By 34 months after the burn (MAB), at the end of the study, emissions from all burned soil sites were virtually indistinguishable from unburned levels. Like the amount of emissions, the chemical signature of the fire (indicated by the EC-Soil ratio) was elevated immediately after the fire and approached pre-burn levels by 24 MAB. Thus, the potential for wind erosion at the Jacob Fire site, as measured by the amount and type of emissions, increased significantly after the fire and returned to unburned levels by 24 MAB. The effect of fire on the potential for water erosion at the Jacob Fire site was more ambiguous. Runoff and sediment from ridge interspace soils and unburned interspace soils were similar throughout the study period. Seldom, if ever, did runoff and sediment occur in burned drainage area soils. For burned soils where runoff occurred at 1 MAB, the sediment size was finer than on unburned sites, but this effect disappeared by 3 MAB. For the three year study under the conditions tested at the Jacob Fire site, the potential for water erosion appeared relatively unaffected by the fire. Vegetation responses were documented for each year following the fire. By the end of the study, there was a substantial difference in plant densities and richness between drainage and ridge sites. Cheatgrass densities were higher in unburned plots, and cheatgrass was also more dominant in the community composition in unburned plots. Cheatgrass had increased in the burned area but so did other native species. Three years after the fire, the burned landscape continued to revegetate but had yet to approximate the condition of an unburned landscape. The results from the vegetation surveys support the wind erosion results, where the primary source of windborne particles originate from the understory, where lower plant diversity and densities were found. The soil appears to be more resilient and have a much shorter recovery time than the vegetation in this particular community.« less

Parameterization of volcanic ash remobilization by wind-tunnel erosion experiments.

NASA Astrophysics Data System (ADS)

Del Bello, Elisabetta; Taddeucci, Jacopo; Merrison, Jonathan; Alois, Stefano; Iversen, Jens Jacob; Scarlato, Piergiorgio

2017-04-01

The remobilization of volcanic ash from the ground is one of the many problems posing threat to life and infrastructures during and after the course of an explosive volcanic eruption. A proper management of the risks connected to this problem requires a thorough understanding of the factors that influence and promote the dispersal of particles over large distances. Towards this target, we conducted a series of experiments aimed at defining first-order processes controlling the remobilization threshold of ash particles by wind erosion. In the framework of the EU-funded Europlanet project, we joinly used the environmental wind tunnel facility at Aarhus University (DK) and the state-of-the art high-speed imaging equipment of INGV experimental lab (Italy) to capture at unparalleled temporal and spatial resolution the removal dynamics of ash-sized (half-millimetre to micron-sized) particles. A homogenous layer of particles was set at on a plate placed downwind a boundary layer setup. Resuspension processes were filmed at 2000 fps and 50 micron pixel resolution, and the plate weighted pre and post-experiment. Explored variables include: 1) wind speed (from ca. 1 to 7 m/s) and boundary layer structure; 2) particle grain size (from 32-63 to 90-125 micron), and sample sorting); 3) chemical and textural features, using basalt and trachyte samples from Campi Flegrei (Pomici Principali,10 ka) and Eyjafjallajökull (May 2010) eruptions; and 4) temperature and humidity, by conducting experiments either at ambient conditions or with a heated sample. We found that the grain size distribution exerts a strong control on the fundamental dynamics of gas-particle coupling. Particles > 90 micron detach from the particles layer individually, also entering the gas flow individually. Conversely, removal < 63 micron particles occurs in clumps of aggregates. These clumps, once taken in charge by the gas flow, are frequently disaggregated and dispersed rapidly (order of few milliseconds). Our preliminary results shows that, for a given size distribution, the boundary between the two dynamics may shift greatly as a function of ambient humidity.

Three decades of Martian surface changes

USGS Publications Warehouse

Geissler, P.E.

2005-01-01

The surface of Mars has changed dramatically during the three decades spanned by spacecraft exploration. Comparisons of Mars Global Surveyor images with Viking and Mariner 9 pictures suggest that more than one third of Mars' surface area has brightened or darkened by at least 10%. Such albedo changes could produce significant effects on solar heating and the global circulation of winds across the planet. All of the major changes took place in areas of moderate to high thermal inertia and rock abundance, consistent with burial of rocky surfaces by thin dust layers deposited during dust storms and subsequent exposure of the rocky surfaces by aeolian erosion. Several distinct mechanisms contribute to aeolian erosion on Mars. Prevailing winds dominate erosion at low latitudes, producing diffuse albedo boundaries and elongated wind streaks generally oriented in the direction of southern summer winds. Dust devils darken the mid to high latitudes from 45 to 70 degrees during the summer seasons, forming irregular albedo patterns consisting of dark linear tracks. Dust storms produce regional albedo variations with distinct but irregular margins. Dark sand duties in southern high latitudes appear to be associated with regional darkening that displays diffuse albedo boundaries. No surface changes were observed to repeat regularly on an annual basis, but many of the changes took place in areas that alternate episodically between high- and low-albedo states as thin mantles of dust are deposited and later stripped off. Hence the face of Mars remains recognizable after a century of telescopic observations, in spite of the enormous extent of alteration that has taken place during the era of spacecraft exploration.

Differential erosion and the formation of layered yardangs in the Loulan region (Lop Nur), eastern Tarim Basin

NASA Astrophysics Data System (ADS)

Lin, Yongchong; Xu, Lishuai; Mu, Guijin

2018-02-01

Yardangs are a type of wind-sculpted landform which generally form in hyper-arid regions. Several factors affect the development of yardangs, and the relative importance of these factors likely varies with differences in regional environmental factors. In the Loulan region of Lop Nur, wind dynamics are the principal factor affecting the development of yardangs. However, layered yardangs, which have undergone a unique form of differential erosion, are common in the region. These erosional landforms differ from typical yardangs which are eroded solely by abrasion and deflation. We conducted field and laboratory investigations of layered yardangs to determine their origin. The results indicate that there are two types of strata comprising the yardangs: uncompacted sand-silt layers, with a lower carbonate content; and compacted clay-silt layers, with a higher carbonate content. Both types of strata are horizontal and occur in alternating layers. This type of structure enables the wind to more easily erode the less resistant sand-silt layers at different heights, leaving the more resistant compacted clay-silt layers relatively intact. Eventually the undercut remnant clay-silt layers collapse once the weight of the suspended strata exceeds their elastic resistance (more than 90% of the fallen blocks have length/thickness ratios between 1.2 and 2.5). Therefore, in addition to wind dynamics, the lithology and structure of the strata are important factors affecting the development of the layered yardangs. This type of differential erosion accelerates the development of the yardangs in the Loulan region.

Weather resistance of CaSO4 ṡ 1/2H2O-based sand-fixation material

NASA Astrophysics Data System (ADS)

Liu, Xin; Tie, Shengnian

2017-07-01

Searching for an economical and effective sand-fixing material and technology is of great importance in Northwest China. This paper described the use of a semihydrated gypsum-(CaSO4 ṡ 1/2H2O-)based composite as a sand-fixing material. Its morphology and composition were characterized by SEM, and its water resistance, freezing-thawing resistance and wind erosion resistance were tested in the field. The results indicated that semihydrated gypsum-(CaSO4 ṡ 1/2H2O-)based sand-fixing composite has good water resistance and water-holding capacity. Its strength is maintained at 1.42 MPa after 50 freezing and thawing cycles, and its wind erosion increases with increasing wind speed and slope. Its compressive strength starts to decrease after nine months of field tests with no change in appearance, but it still satisfies the requirements of fixation technology. This sand-fixing material should have wide application owing to its good weather resistance.

Reduction in soil aggregation in response to dust emission processes

NASA Astrophysics Data System (ADS)

Swet, Nitzan; Katra, Itzhak

2016-09-01

Dust emission by aeolian (wind) soil erosion depends on the topsoil properties of the source area, especially on the nature of the aggregates where most dust particles are held. Although the key role of soil aggregates in dust emission, the response of soil aggregation to aeolian processes and its implications for dust emission remain unknown. This study focuses on aggregate size distribution (ASD) analyses before and after in-situ aeolian experiments in semiarid loess soils that are associated with dust emission. Wind tunnel simulations show that particulate matter (PM) emission and saltation rates depend on the initial ASD and shear velocity. Under all initial ASD conditions, the content of saltator-sized aggregates (63-250 μm) increased by 10-34% due to erosion of macro-aggregates (> 500 μm), resulting in a higher size ratio (SR) between the saltators and macro-aggregates following the aeolian erosion. The results revealed that the saltator production increases significantly for soils that are subjected to short-term (anthropogenic) disturbance of the topsoil. The findings highlight a decrease in soil aggregation for all initial ASD's in response to aeolian erosion, and consequently its influence on the dust emission potential. Changes in ASD should be considered as a key parameter in dust emission models of complex surfaces.

Surface Roughness Investigation of Ultrafine-Grained Aluminum Alloy Subjected to High-Speed Erosion

NASA Astrophysics Data System (ADS)

Kazarinov, N. A.; Evstifeev, A. D.; Petrov, Y. V.; Atroshenko, S. A.; Lashkov, V. A.; Valiev, R. Z.; Bondarenko, A. S.

2016-09-01

This study is the first attempt to investigate the influence of severe plastic deformation (SPD) treatment on material surface behavior under intensive erosive conditions. Samples of aluminum alloy 1235 (99.3 Al) before and after high-pressure torsion (HPT) were subjected to intensive erosion by corundum particles accelerated via air flow in a small-scale wind tunnel. Velocity of particles varied from 40 to 200 m/s, while particle average diameter was around 100 μm. Surface roughness measurements provided possibility to compare surface properties of both materials after erosion tests. Moreover, SPD processing appeared to increase noticeably the threshold velocity of the surface damaging process. Additionally, structural analysis of the fracture surfaces of the tested samples was carried out.

Experimental study on influence of vegetation coverage on runoff in wind-water erosion crisscross region

NASA Astrophysics Data System (ADS)

Wang, Jinhua; Zhang, Ronggang; Sun, Juan

2018-02-01

Using artificial rainfall simulation method, 23 simulation experiments were carried out in water-wind erosion crisscross region in order to analyze the influence of vegetation coverage on runoff and sediment yield. The experimental plots are standard plots with a length of 20m, width of 5m and slope of 15 degrees. The simulation experiments were conducted in different vegetation coverage experimental plots based on three different rainfall intensities. According to the experimental observation data, the influence of vegetation coverage on runoff and infiltration was analyzed. Vegetation coverage has a significant impact on runoff, and the higher the vegetation coverage is, the smaller the runoff is. Under the condition of 0.6mm/min rainfall intensity, the runoff volume from the experimental plot with 18% vegetation coverage was 1.2 times of the runoff from the experimental with 30% vegetation coverage. What’s more, the difference of runoff is more obvious in higher rainfall intensity. If the rainfall intensity reaches 1.32mm/min, the runoff from the experimental plot with 11% vegetation coverage is about 2 times as large as the runoff from the experimental plot with 53%vegetation coverage. Under the condition of small rainfall intensity, the starting time of runoff in the experimental plot with higher vegetation coverage is later than that in the experimental plot with low vegetation coverage. However, under the condition of heavy rainfall intensity, there is no obvious difference in the beginning time of runoff. In addition, the higher the vegetation coverage is, the deeper the rainfall infiltration depth is.The results can provide reference for ecological construction carried out in wind erosion crisscross region with serious soil erosion.

Soil wind erosion in ecological olive trees in the Tabernas desert (southeastern Spain): a wind tunnel experiment

NASA Astrophysics Data System (ADS)

Asensio, Carlos; Lozano, Francisco Javier; Gallardo, Pedro; Giménez, Antonio

2016-08-01

Wind erosion is a key component of the soil degradation processes. The purpose of this study is to find out the influence of material loss from wind on soil properties for different soil types and changes in soil properties in olive groves when they are tilled. The study area is located in the north of the Tabernas Desert, in the province of Almería, southeastern Spain. It is one of the driest areas in Europe, with a semiarid thermo-Mediterranean type of climate. We used a new wind tunnel model over three different soil types (olive-cropped Calcisol, Cambisol and Luvisol) and studied micro-plot losses and deposits detected by an integrated laser scanner. We also studied the image processing possibilities for examining the particles attached to collector plates located at the end of the tunnel to determine their characteristics and whether they were applicable to the setup. Samples collected in the traps at the end of the tunnel were analyzed. We paid special attention to the influence of organic carbon, carbonate and clay contents because of their special impact on soil crusting and the wind-erodible fraction. A principal components analysis (PCA) was carried out to find any relations on generated dust properties and the intensity and behavior of those relationships. Component 1 separated data with high N and OC contents from samples high in fine silt, CO3= and available K content. Component 2 separated data with high coarse silt and clay contents from data with high fine sand content. Component 3 was an indicator of available P2O5 content. Analysis of variance (ANOVA) was carried out to analyze the effect of soil type and sampling height on different properties of trapped dust. Calculations based on tunnel data showed overestimation of erosion in soil types and calculation of the fraction of soil erodible by wind done by other authors for Spanish soils. As the highest loss was found in Cambisols, mainly due to the effect on soil crusting and the wind-erodible fraction aggregation of CaCO3, a Stevia rebaudiana cover crop was planted between the rows in this soil type and this favored retention of particles in vegetation.

Medusae Fossae Formation

NASA Technical Reports Server (NTRS)

2002-01-01

(Released 10 April 2002) The Science This THEMIS visible image was acquired near 7o S, 172o W (188o E) and shows a remarkable martian geologic deposit known as the Medusae Fossae Formation. This Formation, seen here as the raised plateau in the upper two-thirds of the image, is a soft, easily eroded deposit that extends for nearly 1,000 km along the equator of Mars. In this region the deposit has been heavily eroded by the wind to produce a series of linear ridges called yardangs. These parallel ridges point in direction of the prevailing winds that carved them, and demonstrate the power of martian winds to sculpt the dry landscape of Mars. The Medusae Fossae Formation has been completely stripped from the surface in the lower third of the image, revealing a harder layer below that is more resistant to wind erosion. The easily eroded nature of the Medusae Fossae Formation suggests that it is composed of weakly cemented particles, and was most likely formed by the deposition of wind-blown dust or volcanic ash. Several ancient craters that were once completely buried by this deposit are being exposed, or exhumed, as the overlying Medusae Formation is removed. Very few impact craters are visible on this Formation, indicating that the surface seen today is relatively young, and that the processes of erosion are likely to be actively occurring. The Story Medusa of Greek mythology fame, the name-giver to this region, had snaky locks of hair that could turn a person to stone. Wild and unruly, this monster of the underworld could certainly wreak havoc on the world of the human imagination. As scary as she was, Medusa would have no advantage over the fierce, masterful winds blowing across Mars, which once carved the streaky, terrain at the top of this image. Wild and whipping, these winds have slowly eroded away the 'topsoil,' revealing ancient craters and other surface features they once covered. The loosely cemented particles of this 'topsoil' are likely made up of dust or volcanic ash, and are thus more susceptible to windblown erosion. The Martian winds have actually been strong and relentless enough over time to strip the land in the bottom of this image of the material that once covered it, leaving it hard and bare to the eye.

Wind Wave Behavior in Fetch and Depth Limited Estuaries

NASA Astrophysics Data System (ADS)

Karimpour, Arash; Chen, Qin; Twilley, Robert R.

2017-01-01

Wetland dominated estuaries serve as one of the most productive natural ecosystems through their ecological, economic and cultural services, such as nursery grounds for fisheries, nutrient sequestration, and ecotourism. The ongoing deterioration of wetland ecosystems in many shallow estuaries raises concerns about the contributing erosive processes and their roles in restraining coastal restoration efforts. Given the combination of wetlands and shallow bays as landscape components that determine the function of estuaries, successful restoration strategies require knowledge of wind wave behavior in fetch and depth limited water as a critical design feature. We experimentally evaluate physics of wind wave growth in fetch and depth limited estuaries. We demonstrate that wave growth rate in shallow estuaries is a function of wind fetch to water depth ratio, which helps to develop a new set of parametric wave growth equations. We find that the final stage of wave growth in shallow estuaries can be presented by a product of water depth and wave number, whereby their product approaches 1.363 as either depth or wave energy increases. Suggested wave growth equations and their asymptotic constraints establish the magnitude of wave forces acting on wetland erosion that must be included in ecosystem restoration design.

Wind Wave Behavior in Fetch and Depth Limited Estuaries

PubMed Central

Karimpour, Arash; Chen, Qin; Twilley, Robert R.

2017-01-01

Wetland dominated estuaries serve as one of the most productive natural ecosystems through their ecological, economic and cultural services, such as nursery grounds for fisheries, nutrient sequestration, and ecotourism. The ongoing deterioration of wetland ecosystems in many shallow estuaries raises concerns about the contributing erosive processes and their roles in restraining coastal restoration efforts. Given the combination of wetlands and shallow bays as landscape components that determine the function of estuaries, successful restoration strategies require knowledge of wind wave behavior in fetch and depth limited water as a critical design feature. We experimentally evaluate physics of wind wave growth in fetch and depth limited estuaries. We demonstrate that wave growth rate in shallow estuaries is a function of wind fetch to water depth ratio, which helps to develop a new set of parametric wave growth equations. We find that the final stage of wave growth in shallow estuaries can be presented by a product of water depth and wave number, whereby their product approaches 1.363 as either depth or wave energy increases. Suggested wave growth equations and their asymptotic constraints establish the magnitude of wave forces acting on wetland erosion that must be included in ecosystem restoration design. PMID:28098236

Wind Wave Behavior in Fetch and Depth Limited Estuaries.

PubMed

Karimpour, Arash; Chen, Qin; Twilley, Robert R

2017-01-18

Wetland dominated estuaries serve as one of the most productive natural ecosystems through their ecological, economic and cultural services, such as nursery grounds for fisheries, nutrient sequestration, and ecotourism. The ongoing deterioration of wetland ecosystems in many shallow estuaries raises concerns about the contributing erosive processes and their roles in restraining coastal restoration efforts. Given the combination of wetlands and shallow bays as landscape components that determine the function of estuaries, successful restoration strategies require knowledge of wind wave behavior in fetch and depth limited water as a critical design feature. We experimentally evaluate physics of wind wave growth in fetch and depth limited estuaries. We demonstrate that wave growth rate in shallow estuaries is a function of wind fetch to water depth ratio, which helps to develop a new set of parametric wave growth equations. We find that the final stage of wave growth in shallow estuaries can be presented by a product of water depth and wave number, whereby their product approaches 1.363 as either depth or wave energy increases. Suggested wave growth equations and their asymptotic constraints establish the magnitude of wave forces acting on wetland erosion that must be included in ecosystem restoration design.

Effect of ecological restoration and climate change on ecosystems: a case study in the Three-Rivers Headwater Region, China.

PubMed

Jiang, Chong; Zhang, Linbo

2016-06-01

The Three-Rivers Headwater Region (TRHR) is the headwater of the Yangtze River Basin (YARB), Yellow River Basin (YRB), and Lancang River Basin (LRB); it is known as China's 'Water Tower' owing to its important supply of freshwater. In order to assess ecosystem changes in the TRHR during 2000-2012, we systematically and comprehensively evaluated a combination of model simulation results and actual observational data. The results showed the following: (1) Ecosystem pattern was relatively stable during 2000-2010, with a slight decrease in farmland and desert areas, and a slight increase in grassland and wetland/water-body areas. (2) A warmer and wetter climate, and ecological engineering, caused the vegetation cover and productivity to significantly improve. (3) Precipitation was the main controlling factor for streamflow. A significant increase in precipitation during 2000-2012 resulted in an obvious increase in annual and seasonal streamflow. Glacier melting also contributed to the streamflow increase. (4) The total amount of soil conservation increased slightly from 2000 to 2012. The increase in precipitation caused rainfall erosivity to increase, which enhanced the intensity of soil erosion. The decrease in wind speed decreased wind erosion and the frequency of sandstorms. (5) The overall habitat quality in the TRHR was stable between 2000 and 2010, and the spatial pattern exhibited obvious heterogeneity. In some counties that included nature reserves, habitat quality was slightly higher in 2010 than in 2000, which reflected the effectiveness of the ecological restoration. Overall, the aforementioned ecosystem changes are the combined results of ecological restoration and climate change, and they are likely a local and temporary improvement, rather than a comprehensive and fundamental change. Therefore, more investments and efforts are needed to preserve natural ecosystems.

Erosive events in dilute pyroclastic density currents

NASA Astrophysics Data System (ADS)

Douillet, G.; Kueppers, U.; Rasmussen, K.; Merrison, J. P.; Dingwell, D. B.

2011-12-01

Our understanding of the dynamics of pyroclastic density currents (PDCs) is largely based on the study of their deposits. However, sedimentological structures reflect only the low energy, depositional phases of a flow. To enlarge the source of information on PDC behaviour, we provided wind-tunnel experiments to measure the minimal velocity necessary to erode dry, volcanic ash. Our results permit to link erosive surfaces that are often found in PDC deposits to the minimum velocity that must have acted to produce them. We apply the method to field examples and discuss the occurrence of hydraulic-jumps in dilute PDCs. We measured the threshold of surface friction-velocity for erosion of two types of volcanic ash: 1) a mixture of fragments of vesiculated scoria containing also lithics and crystals and 2) pumice clasts from the Plinian Laacher See eruption. Both were sampled in quarries from the East Eifel volcanic field (Germany). For each type, we measured the threshold for particles from 63 μm to 2 mm in 1 phi-size steps. Static threshold friction-velocities have been measured experimentally in an open, 6 m-long wind-tunnel at Aarhus University. In order to quickly guarantee the downwind equilibrium-dynamics of the saltating sand-surface, we produced roughness-carpets upstream of the study area. The roughness-carpets consist of particles of the measured sample fixed onto the bed in order to create an appropriate static roughness. The measuring section (1 m in length) is located at the downwind end of the wind-tunnel and covered with 10 mm of sample. The wind velocity in the wind-tunnel was progressively increased until a small but continuous number of grains left the surface. This wind velocity was taken as the threshold, and the associated surface friction-velocity was deduced by calibration from wind-profiles data taken over the fixed surface of material of the same characteristics. We apply our results to sedimentary features found in natural deposits and usually interpreted as "chute and pool" structures. These are characterized by erosional events producing a steep side facing the flow, and lensoidal layers deposited on the stoss face of the un-eroded, remaining strata. Our experimental results allow for quantifying the minimum current-velocity required for the observed erosion. Based on this, we discuss the interpretation of such erosional features as "chute and pool" structures, which are the sedimentary record of hydraulic-jumps. There is no clear evidence of the presence of internal hydraulic-jumps in the sedimentary record of PDCs. Moreover, such flows can decelerate drastically and eventually stop without leaving the supercritical flow regime due to their highly depositional nature. Accordingly, they would not experience a hydraulic-jump.

Do erosion control and snakes mesh?

Treesearch

Christopher Barton; Karen Kinkead

2005-01-01

In the battle to curb soil erosion and sedimentation, numberous techniques and products for controlling erosion and sedimentation have been developed and are being implemented. Rolled erosion control products, such as a temporary erosion control blankets and permanent turf reinforcement mats, represent one type of erosion control product that has been used extensively...

7 CFR 1469.3 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... grazing are used, with little or no chemicals or fertilizer being applied. Grasslands, savannas, prairie... soil organic matter content through soil disturbance or by sheet, rill, and wind erosion, and the...

Dust storms on Mars: Considerations and simulations

NASA Technical Reports Server (NTRS)

Greeley, R.; White, B. R.; Pollack, J. B.; Iverson, J. D.; Leach, R. N.

1977-01-01

Aeolian processes are important in modifying the surface of Mars at present, and appear to have been significant in the geological past. Aeolian activity includes local and global dust storms, the formation of erosional features such as yardangs and depositional features such as sand dunes, and the erosion of rock and soil. As a means of understanding aeolian processes on Mars, an investigation is in progress that includes laboratory simulations, field studies of earth analogs, and interpretation of spacecraft data. This report describes the Martian Surface Wind Tunnel, an experimental facility established at NASA-Ames Research Center, and presents some results of the general investigation. Experiments dealing with wind speeds and other conditions required for the initiation of particle movement on Mars are described and considerations are given to the resulting effectiveness of aeolian erosion.

The Multi-Stage History of Mt. Sharp

NASA Technical Reports Server (NTRS)

Allen, C.; Dapremont, A.

2013-01-01

The Curiosity rover is exploring Gale crater and Mt. Sharp, Gale's 5-km high central mound. We are investigating the history of alteration and erosion of Mt. Sharp using orbital imagery, spectroscopy and rover observations. Our results suggest a significant time gap between emplacement of the upper and lower sections of the mound. Crater counts show that the lower mound was formed soon after Gale itself, and that it contains distinct units ranging in altitude from approximately -4,500 to -1,800 m. Spectral data suggest that many units contain phyllosilicates. We found that these clay-bearing rocks occur in distinct layers concentrated below -2,900 m. Parts of the lower mound exhibit a transition from clays to sulfates with increasing altitude. The lower mound shows evidence of flowing water, including canyons and inverted channels. Wind erosion produced km-scale yardangs and scalloped cliffs. Our mapping shows that many yardangs in the lower mound are clay-bearing, with a predominant orientation of around N-S. Curiosity's ground-level images show myriad fine-scale, mainly horizontal layers in the lower mound. The rover has found stream beds and conglomerates, indicating that water once flowed on the crater floor. Drilling near the deepest point in Gale produced abundant clay, providing additional evidence of aqueous alteration. Upper mound units range in altitude from -2,100 m to +500 m, and mantle the lower mound above an angular unconformity. Most upper mound units are composed of layers. The formation age of the upper mound is unknown, since few craters are preserved. Clay-bearing layers are detectable in several locations, mainly at altitudes near -2,000 m. There is no evidence of water flow, but wind erosion has scalloped the surfaces and edges of layers, and fine-scale yardangs are common. Correlations between yardangs and clay spectra are apparent only in the lowermost units of the upper mound. Yardang orientations vary, and include N-S, NW-SE, and NE-SW. Upper mound units resemble the planet-wide Medusae Fossae formation, dated as Hesperian and argued to be composed of ignimbrites. Medusae Fossae layers are easily eroded by wind, and our mapping demonstrates their resemblance to upper mound fine-scale yardangs. The history of Mt. Sharp started with deposition and lithification of sediments shortly after crater formation. Some lower mound layers were partially altered to clays and sulfates, and water formed streams and canyons. Wind erosion of the lower mound produced large-scale yardangs, particularly in clay-rich layers, oriented generally N-S. Upper mound units were emplaced following a considerable period of wind erosion. The absence of water flow on the upper mound suggests that these units were emplaced after atmospheric loss rendered water unstable at the surface. The shift in dominant wind direction, as indicated by yardang orientations, also argues for a time gap between erosion of the lower and upper mound. These observations are consistent with upper mound units being related to the Hesperian Medusae Fossae formation. During 2014 Curiosity is expected to reach the foot of Mt. Sharp and ascend through the clay-rich layers, into the sulfate-rich layers, and possibly past the interface with the upper mound. This will be a unique opportunity to field check geologic models on the surface of Mars.

Quantifying postfire aeolian sediment transport using rare earth element tracers

USGS Publications Warehouse

Dukes, David; Gonzales, Howell B.; Ravi, Sujith; Grandstaff, David E.; Van Pelt, R. Scott; Li, Junran; Wang, Guan; Sankey, Joel B.

2018-01-01

Grasslands, which provide fundamental ecosystem services in many arid and semiarid regions of the world, are undergoing rapid increases in fire activity and are highly susceptible to postfire-accelerated soil erosion by wind. A quantitative assessment of physical processes that integrates fire-wind erosion feedbacks is therefore needed relative to vegetation change, soil biogeochemical cycling, air quality, and landscape evolution. We investigated the applicability of a novel tracer technique—the use of multiple rare earth elements (REE)—to quantify soil transport by wind and to identify sources and sinks of wind-blown sediments in both burned and unburned shrub-grass transition zone in the Chihuahuan Desert, NM, USA. Results indicate that the horizontal mass flux of wind-borne sediment increased approximately threefold following the fire. The REE tracer analysis of wind-borne sediments shows that the source of the horizontal mass flux in the unburned site was derived from bare microsites (88.5%), while in the burned site it was primarily sourced from shrub (42.3%) and bare (39.1%) microsites. Vegetated microsites which were predominantly sinks of aeolian sediments in the unburned areas became sediment sources following the fire. The burned areas showed a spatial homogenization of sediment tracers, highlighting a potential negative feedback on landscape heterogeneity induced by shrub encroachment into grasslands. Though fires are known to increase aeolian sediment transport, accompanying changes in the sources and sinks of wind-borne sediments may influence biogeochemical cycling and land degradation dynamics. Furthermore, our experiment demonstrated that REEs can be used as reliable tracers for field-scale aeolian studies.

Biological soil crusts as soil stabilizers: Chapter 16

USGS Publications Warehouse

Belnap, Jayne; Buedel, Burkhard; Weber, Bettina; Buedel, Burkhard; Belnap, Jayne

2016-01-01

Soil erosion is of particular concern in dryland regions, as the sparse cover of vascular plants results in large interspaces unprotected from the erosive forces of wind and water. Thus, most of these soil surfaces are stabilized by physical or biological soil crusts. However, as drylands are extensively used by humans and their animals, these crusts are often disturbed, compromising their stabilizing abilities. As a result, approximately 17.5% of the global terrestrial lands are currently being degraded by wind and water erosion. All components of biocrusts stabilize soils, including green algae, cyanobacteria, fungi, lichens, and bryophytes, and as the biomass of these organisms increases, so does soil stability. In addition, as lichens and bryophytes live atop the soil surface, they provide added protection from raindrop impact that cyanobacteria and fungi, living within the soil, cannot. Much research is still needed to determine the relative ability of individual species and suites of species to stabilize soils. We also need a better understanding of why some individuals or combination of species are better than others, especially as these organisms become more frequently used in restoration efforts.

Estimation of saltation emission in the Kubuqi Desert, North China.

PubMed

Du, Heqiang; Xue, Xian; Wang, Tao

2014-05-01

The Kubuqi Desert suffered more severe wind erosion hazard. Every year, a mass of aeolian sand was blown in the Ten Tributaries that are tributaries of the Yellow River. To estimate the quantity of aeolian sediment blown into the Ten Tributaries from the Kubuqi Desert, it is necessary to simulate the saltation processes of the Kubuqi Desert. A saltation submodel of the IWEMS (Integrated Wind-Erosion Modeling System) and its accompanying RS (Remote Sensing) and GIS (Geographic Information System) methods were used to model saltation emissions in the Kubuqi Desert. To calibrate the saltation submodel, frontal area of vegetation, soil moisture, wind velocity and saltation sediment were observed synchronously on several points in 2011 and 2012. In this study, a model namely BEACH (Bridge Event And Continuous Hydrological) was introduced to simulate the daily soil moisture. Using the surface parameters (frontal area of vegetation and soil moisture) along with the observed wind velocities and saltation sediments for the observed points, the saltation model was calibrated and validated. To reduce the simulate error, a subdaily wind velocity program, WINDGEN was introduced in this model to simulate the hourly wind velocity of the Kubuqi Desert. By incorporating simulated hourly wind velocity, and model variables, the saltation emission of the Kubuqi Desert was modeled. The model results show that the total sediment flow rate was 1-30.99 tons/m over the last 10years (2001-2010). The saltation emission mainly occurs in the north central part of the Kubuqi Desert in winter and spring. Integrating the wind directions, the quantity of the aeolian sediment that deposits in the Ten Tributaries was estimated. Compared with the observed data by the local government and hydrometric stations, our estimation is reasonable. Copyright © 2014 Elsevier B.V. All rights reserved.

Quantifying Post-Fire Aeolian Sediment Transport Using Rare Earth Element Tracers.

NASA Astrophysics Data System (ADS)

Dukes, D.; Ravi, S.; Grandstaff, D. E.; Gonzales, H. B.; Li, J. J.; Sankey, J. B.; Wang, G.; Van Pelt, R. S.

2016-12-01

Grasslands and rangelands in arid and semi-arid regions of the world, which provide fundamental ecosystem services, are undergoing rapid increases in fire activity and are highly susceptible to post-fire accelerated soil erosion by wind. A quantitative assessment that integrates fire-wind erosion feedbacks is therefore critically needed in understanding vegetation change, soil biogeochemical cycling, air quality, and landscape evolution. We investigated the applicability of a novel tracer technique - the use of rare earth element (REE) tracers - to quantify soil erosion by wind and to identify sources and sinks of wind-blown sediments in both a burned and unburned shrub-grass transition zone within the Chihuahuan desert (New Mexico, USA). At the beginning of the windy season, March 2016, silt and sand sized particles in shrub, grass, and bare microsites were each tagged with a unique REE oxide, Ho, Eu, and Yb respectively. Samples were then taken directly after application prior to a prescribed fire and again at the end of the windy season in June 2016. All REE tracers showed signs of depletion and mixing, with the depletion in the burned site up to 20% greater than the unburned. REE concentration comparisons between the burned and unburned plots reveal a shift in the source and sink dynamics of sediment post fire. In unburned plots, changes in microsite REE concentrations indicate that sediment moved from the bare to vegetated microsites, whereas the opposite occurred in burned plots. However, burned plot grass microsites acted as a sink for sediment from shrub microsites, whereas unburned plot grass microsites exhibited no enrichment from shrub microsite-sourced sediment. Though fires are known to immediately increase aeolian sediment transport, accompanying changes in the sources and sinks of wind borne sediment may influence biogeochemical cycling and vegetation shifts possibly providing a feedback mechanism for land degradation in dryland ecosystems.

Modeling storm and sea level rise impacts on marsh transgression

NASA Astrophysics Data System (ADS)

Carr, J. A.; Guntenspergen, G. R.; Kirwan, M. L.

2016-12-01

Coastal salt marsh systems provide critical ecosystem services, including key habitat and coastal protection. Both lateral extent, and vertical stability of salt marshes to sea level rise have been shown to be functions of both biotic, and abiotic drivers and feedbacks. As a result, the ecogeomorphic evolution of the system can exhibit strong non-linearities, discontinuities and thresholds. We developed a two-dimensional transect model to explore controls on marsh lateral extent, vertical stability and the potential for marsh transgression inland and upland. Salt marsh and upland regions in the model are discretized in 1 m increments with inundation frequency determined by the elevation of the individual cells, organogenic soil formation and mineral deposition rates, and the history of stochastic water levels. The transect extends from an idealized back barrier bay across the salt marsh platform and into the upland forest and is forced with auto and cross correlated synthetic stochastic wind speed, wind direction and water levels. The model incorporates key feedbacks between fetch, wave growth and subsequent lateral erosion rates and sediment supply to the marsh platform. Deposition of mineral sediment from the bay and/or internal ponds onto the marsh platform cells is dependent both on the inundation frequency and distance from a marsh edge. For each element along the transect, a Markov chain successional model was implemented that considers six distinct states, grass/saltmarsh, seedling, sapling, tree, dead standing tree, and bare. A non-static transition probability matrix, dependent on both inundation of the element and the prior vegetation state, was used in order to allow for feedbacks, both positive and negative, among different vegetation states and environmental drivers. The model was used to examine the qualitative behavior of the coupled systems under varied rates of sea level rise, external sediment supply, wind and storm statistics, tidal range, upland slope, and initial bay width. Interestingly, water level statistics had strong controls on rates of lateral marsh erosion, ponding and upland marsh migration with the landward marsh edge controlled by upland slope and the timing and frequency of extreme water events.

Plant materials and amendments for controlling wind and water erosion on a fly ash disposal area: TVA Colbert Fossil Plant, Alabama

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

Maddox, J.J.; Behel, D.; Soileau, J.M.

1996-12-31

Fly ash disposal sites adjacent to fossil fueled generating plants are subject to wind and water erosion which increases the operation and maintenance costs. Gullies and unstable areas in the disposal sites require expensive leveling and filling practices. Test evaluated both warm- and cool-season cover crops established by either sod or seed. Amendments to the ash consisted of composted poultry litter (CPL), soil, soil+CPL, fertilizer and beneficial soil microbes including mycorrhizal fungi. Turf sods (419 Bermuda, Emerald zoysia, and Raleigh St. Augustine) were compared in greenhouse and field studies. Six legumes and 12 grass species were tested in the greenhousemore » as seeded cover crops using similar amendments and raw poultry litter (PL). Legumes grew better with CPL and Boil amendments and grasses grew better on PL and soil amendments possibly due to differences in N requirements and N supply. Cool season crops generally grew faster than warm season species in the greenhouse tests. Amendments should be mixed with the FA to ameliorate the effects of boron and salt toxicity and to increase the water holding capacity. Bermuda sod grew faster than either St, Augustine or Emerald zoysia, but requires more water. A microbial amendment increased dry matter yields of bermuda sod 2 to 3 times after 40 to 60 days over unamended controls. Microbial amendments may be justified on an economic and sustainable basis. A field study is assessing the environmental and cultural requirements to grow a cover crop on an annual basis.« less

Venus

NASA Technical Reports Server (NTRS)

Saunders, R. S.; Carr, M. H.

1984-01-01

The following aspects of the planet Venus are discussed: orbit, rotation, composition, wind erosion, topography, surface roughness, gravity, and tectonics. The Venera satellites, Pioneer space probes, and Mariner space probes involved in Venusian exploration are enumerated.

The Effect of Grain Refinement on Solid Particle Erosion of Grade 5 Ti Alloy

NASA Astrophysics Data System (ADS)

Kazarinov, N. A.; Evstifeev, A. D.; Petrov, Y. V.; Atroshenko, S. A.; Valiev, R. R.

2018-04-01

In this work, the results on solid particle erosion of an ultrafine-grained Grade 5 titanium alloy, which was produced using high-pressure torsion (HPT) technique, are presented. In order to assess influence of the HPT treatment on material's behavior in erosive conditions, special experimental procedures were developed. The ultrafine-grained (UFG) alloy was tested alongside with a conventional coarse-grained (CG) Grade 5 titanium alloy in equal conditions. The experiments were conducted in a small-scale wind tunnel with corundum particles as an abrasive material. Both particle dimensions and particle velocities were varied in course of the experiments. Erosion resistance of the samples was evaluated in two ways—mass reduction measurements with subsequent gravimetric erosion rate calculations and investigation of samples' surface roughness after erosion tests. The UFG titanium alloy demonstrated considerable improvement of static mechanical properties (ultimate tensile strength, microhardness), whereas its CG counterpart appeared to be slightly more resistant to solid particle erosion, which might indicate the drop of dynamic strength properties for the HPT-processed material.

To what extent can we attribute accelerated landscape change to human activity? A cautionary tale from the drylands of the South African interior

NASA Astrophysics Data System (ADS)

Tooth, Stephen; Lyons, Richard; Duller, Geoff; McCarthy, Terence

2013-04-01

Across many parts of interior South Africa, alluvial and colluvial sediments are currently subject to widespread erosion by rivers, dongas (gullies), sheetwash and wind. This creates an impression of accelerated landscape change that is commonly attributed to factors such as poor land management by European settlers (mid 18th century onwards) or indigenous peoples, possibly in combination with decadal-scale climatic fluctuations and/or susceptible soil characteristics. Many resources are devoted to managing degrading lands, but effective conservation and restoration efforts are contingent on correctly identifying the underlying causes of erosion. Across South Africa, varied population densities, and diverse climates and soil types, mean that the causes of erosion are likely to be complex and to vary regionally. In some regions, examples of accelerated erosion resulting from vegetation clearance, overburning, overstocking, artificial drainage or land abandonment can be demonstrated. In other regions, however, our geomorphological, sedimentological and geochronological investigations provide an alternative 'geological' perspective on this erosion 'problem' by demonstrating that erosion may be a recurring, natural process linked to late Quaternary climate change and/or longer term landscape denudation. In particular, luminescence chronologies for hillslopes, alluvial fans and river floodplains/terraces at various locations across interior South Africa have enabled comparison with other regional/global palaeoenvironmental records. These comparisons reveal that climatically-controlled changes in runoff and sediment supply, mediated through vegetation cover changes, resulted in shifts between sedimentation (relative aridity), soil formation (relative humidity) and minor channel/donga erosion (semiaridity) from at least 40 kyr until the late Holocene. By contrast, major erosion involving sustained channel incision and associated donga formation appears to have been initiated during the last few thousand years, at some sites apparently corresponding with rapid climatic fluctuations associated with the Mediaeval Warm Period and Little Ice Age. In some instances, channel incision depth has been controlled by the stability of downstream resistant rock barriers (e.g. dolerite sills and dykes) that form local baselevels in river long profiles; upstream of stable barriers, incision has been restricted but where barriers have been partially or fully breached, then deep incision into bedrock is characteristic. These findings provide evidence that: 1) during the late Quaternary, erosional phases have occurred independently of human activity, in different climatic settings, and across different soil types; and 2) in many regions, even the present phase of deep channel incision and donga formation predates the advent of European settlement or indigenous population expansion. These 'geological' perspectives on the age and history of major erosional features demonstrate that accelerated landscape change in South Africa is not necessarily a consequence of human activities, and cannot be assumed to represent an unequivocal signature of the Anthropocene. These perspectives also have implications for land management. Where erosion is indisputably occurring as a result of land mismanagement, then alternative land use practices and erosion-control measures may succeed in slowing or reversing erosion, but where erosion results from natural climatic or denudational processes, then such schemes are unlikely to succeed in the medium- or long-term.

Space Environmental Erosion of Polar Icy Regolith

NASA Technical Reports Server (NTRS)

Farrell, William M.; Killen, R. M.; Vondrak, R. R.; Hurley, D. M.; Stubbs, T. J.; Delory, G. T.; Halekas, J. S.; Zimmerman, M. I.

2011-01-01

While regions at the floors of permanently shadowed polar craters are isolated from direct sunlight, these regions are still exposed to the harsh space environment, including the interplanetary Lyman-a background, meteoric impacts, and obstacle-affected solar wind. We demonstrate that each of these processes can act to erode the polar icy regolith located at or near the surface along the crater floor. The Lyman-a background can remove/erode the icy-regolith via photon stimulated desorption [1], meteoric impacts can vaporize the regolith [2], and redirected solar wind ions can sputter the ice-regolith mix [3]. As an example we shall examine in detail the inflow of solar wind ions and electrons into polar craters, One might expect such ions to flow horizontally over the crater top (see Figure). However, we find that plasma ambipolar processes act to deflect passing ions into the craters [3]. We examine this plasma process and determine the ion flux as a function of position across a notional crater floor. We demonstrate that inflowing solar wind ions can indeed create sputtering along the crater floor, effectively eroding the surface. Erosion time scales rrom sputtering will be presented. We shall also consider the effect of impact vaporization on buried icy-regolith regions. There will also be a discussion of solar wind electrons that enter into the PSR, demonstrating that these also have the ability rree surface-bound atoms via electron stimulated desorption processes [l].

Analysis of Actual Soil Degradation by Erosion Using Satellite Imagery and Terrain Attributes in the Czech Republic

NASA Astrophysics Data System (ADS)

Zizala, Daniel

2015-04-01

Soil water and wind erosion (possibly tillage erosion) is the most significant soil degradation factor in the Czech Republic. Moreover, this phenomenon also affects seriously quality of water sources., About 50 % of arable land are endangered by water erosion and about 10 % of arable land are endangered wind erosion in the Czech Republic. These processes have been accelerated by human activity. Specific condition of agriculture land in the Czech Republic including highland relief and particularly size of land parcel and intensification of agriculture does not enable to reduce flow of runoff water. Insufficient protection against accelerated erosion processes is related to lack of landscape and hydrographic elements and large area of agricultural plots. Currently, this issue is solved at plot scale by field investigation or at regional scale using numerical and empirical erosion models. Nevertheless, these models enable only to predict the potential of soil erosion. Large scale assessment of actual degradation level of soils is based on expert knowledge. However, there are still many uncertainties in this issue. Therefore characterization of actual degradation level of soil is required especially for assessment of long-term impact of soil erosion on soil fertility. Soil degradation by erosion can be effectively monitored or quantified by modern tools of remote sensing with variable level of detail accessible. Aims of our study is to analyse the applicability of remote sensing for monitoring of actual soil degradation by erosion. Satellite and aerial image data (multispectral and hyperspectral), terrain attributes and data from field investigation are the main source for this analyses. The first step was the delimitation of bare soils using supervised classification of the set of Landsat scenes from 2000 - 2014. The most suitable period of time for obtaining spectral image data with the lowest vegetation cover of soil was determined. The results were verified by statistical data of areas under farm crops from Czech Statistical Office. Information on number of scenes where bare soils are identified for each land parcel is available. This set of images with bare soils is used for assessment of soil degradation stage. Some land parcels were found without vegetation cover up to 40 times. Analysis was performed on 5 test sites in the Czech Republic and also using data from database of Soil Erosion Monitoring of Agricultural Land. Currently, more than 500 erosion events are registered in this database. Additional remote sensing data (Hyperion data, aerial hyperspectral data) was used for detailed analysis on the test sites. Results reveal that satellite imagery set, soil maps, terrain attributes and erosion modelling can be successfully applied in assessment of actual soil degradation by erosion. The research has been supported by the project no. QJ330118 "Using Remote Sensing for Monitoring of Soil Degradation by Erosion and Erosion Effects" funding by Ministry of Agriculture.

Sedimentology and geomorphology analysis of coastal area along pantai penarik, terengganu before and during northeast monsoon season

NASA Astrophysics Data System (ADS)

Yusoff, Tengku Ahmad Imran Ku; Shaufi Sokiman, Mohamad

2017-10-01

This research is conducted to understand the sedimentology and morphological change before and during the northeast monsoon at the east coast of peninsular Malaysia. The increase in wind speed, wave energy and rainfall during the northeast monsoon are believed to causes the coastal erosion to increase during the season. Rapid development along the east coast area might disrupt the sediments distribution which can increase the coastal erosion rate every year. The understanding on the sediments distribution, erosion and deposition as well as the morphological change can help to figure out if the coastal erosion can affect the infrastructure in the future. The result of the study can show the necessity to perform mitigation or any required action toward the problem that might happen

Aeolian transport of biota with dust: A wind tunnel experiment

NASA Astrophysics Data System (ADS)

Rivas, J. A., Jr.; Gill, T. E.; Van Pelt, R. S.; Walsh, E.

2015-12-01

Ephemeral wetlands are ideal sources for dust emission, as well as repositories for dormant stages of aquatic invertebrates. An important component of invertebrate dispersal and colonization to new areas is the ability to be entrained into the atmosphere. Aquatic invertebrate eggs fall within the size of dust and sand grains (30-600μm), are less dense and aerodynamically shaped. We have shown previously that aquatic invertebrates can be dispersed long distances in dust storms but the extent of transport of taxa based on diapausing egg size/morphology has not been investigated. Here, we control the wind erosion process in a wind tunnel to test entrainment of diapausing stages of brine shrimp, clam shrimp, tadpole shrimp, fairy shrimp, Daphnia, and the rotifers Brachionus plicatilis and B. calyciflorus into the air by saltation. Diapausing eggs were mixed with sterilized wind-erodible soil. The soil/egg mixture was moistened with distilled water and air dried to form a crust. Dust was generated in a wind tunnel by releasing sand grains that act as saltator material similar to wind-entrained natural sands. Maximum wind velocity was 10m/s and entrained particles were sampled through an isokinetic horizontal intake opening. Aeolian sediment was collected from three points in the system; transfer section for coarse sediment, the pan subtending a settling chamber for finer saltation-sized sediment, and two paper filters for suspension-sized sediment. Samples were then passed through 250 and 350 μm sieves to remove abrader sand and rehydrated with various sterile media depending on the type of organism. We retrieved viable brine, fairy, and tadpole shrimp, ostracods, Daphnia, and diapausing eggs of the rotifers after hydration. This experiment demonstrates that resting stages of many invertebrates can be wind-eroded due to size and egg morphology and remain viable under controlled conditions mimicking dust emission.

On the Material Characterisation of Wind Turbine Blade Coatings: The Effect of Interphase Coating–Laminate Adhesion on Rain Erosion Performance

PubMed Central

Cortés, Enrique; Sánchez, Fernando; Madramany, Borja

2017-01-01

Rain erosion damage, caused by repeated droplet impact on wind turbine blades, is a major cause for concern, even more so at offshore locations with larger blades and higher tip speeds. Due to the negative economic influence of blade erosion, all wind turbine Original Equipment Manufacturers (OEMs) are actively seeking solutions. In most cases, since the surface coating plays a decisive role in the blade manufacture and overall performance, it has been identified as an area where a solution may be obtained. In this research, two main coating technologies have been considered: In-mould coatings (Gel coating) applied during moulding on the entire blade surface and the post-mould coatings specifically developed for Leading Edge Protection (LEP). The coating adhesion and erosion is affected by the shock waves created by the collapsing water droplets on impact. The stress waves are reflected and transmitted to the laminate substrate, so microstructural discontinuities in coating layers and interfaces play a key role on its degradation and may accelerate erosion by delamination. Analytical and numerical models are commonly used to relate lifetime prediction and to identify suitable coating and composite substrate combinations based on their potential stress reduction on the interface. Nevertheless, in order to use them, it is necessary to measure the contact adhesion resistance of the multi-layered system interfaces. The rain erosion performance is assessed using an accelerated testing technique, whereby the test material is repeatedly impacted at high speed with water droplets in a Whirling Arm Rain Erosion Rig (WARER). The materials, specifically the coating–laminate interphase region and acoustic properties, are further characterised by several laboratory tests, including Differential Scanning Calorimetry (DSC), pull-off testing, peeling–adhesion testing and nanoindentation testing. This body of work includes a number of case studies. The first case study compares two of the main coating technologies used in industry (i.e., gel coating and LEP); the second case investigates the effects of the in-mould gel coating curing; and the third considers the inclusion of a primer layer on a LEP configuration system. Following these case studies, the LEP is found to be a far superior coating due to its appropriate mechanical and acoustic properties and the interface between the coating and the substrate is highlighted as a key aspect, as poor adhesion can lead to delamination and, ultimately, premature failure of the coating. PMID:28956841

On the Material Characterisation of Wind Turbine Blade Coatings: The Effect of Interphase Coating-Laminate Adhesion on Rain Erosion Performance.

PubMed

Cortés, Enrique; Sánchez, Fernando; O'Carroll, Anthony; Madramany, Borja; Hardiman, Mark; Young, Trevor M

2017-09-28

Rain erosion damage, caused by repeated droplet impact on wind turbine blades, is a major cause for concern, even more so at offshore locations with larger blades and higher tip speeds. Due to the negative economic influence of blade erosion, all wind turbine Original Equipment Manufacturers (OEMs) are actively seeking solutions. In most cases, since the surface coating plays a decisive role in the blade manufacture and overall performance, it has been identified as an area where a solution may be obtained. In this research, two main coating technologies have been considered: In-mould coatings (Gel coating) applied during moulding on the entire blade surface and the post-mould coatings specifically developed for Leading Edge Protection (LEP). The coating adhesion and erosion is affected by the shock waves created by the collapsing water droplets on impact. The stress waves are reflected and transmitted to the laminate substrate, so microstructural discontinuities in coating layers and interfaces play a key role on its degradation and may accelerate erosion by delamination. Analytical and numerical models are commonly used to relate lifetime prediction and to identify suitable coating and composite substrate combinations based on their potential stress reduction on the interface. Nevertheless, in order to use them, it is necessary to measure the contact adhesion resistance of the multi-layered system interfaces. The rain erosion performance is assessed using an accelerated testing technique, whereby the test material is repeatedly impacted at high speed with water droplets in a Whirling Arm Rain Erosion Rig (WARER). The materials, specifically the coating-laminate interphase region and acoustic properties, are further characterised by several laboratory tests, including Differential Scanning Calorimetry (DSC), pull-off testing, peeling-adhesion testing and nanoindentation testing. This body of work includes a number of case studies. The first case study compares two of the main coating technologies used in industry (i.e., gel coating and LEP); the second case investigates the effects of the in-mould gel coating curing; and the third considers the inclusion of a primer layer on a LEP configuration system. Following these case studies, the LEP is found to be a far superior coating due to its appropriate mechanical and acoustic properties and the interface between the coating and the substrate is highlighted as a key aspect, as poor adhesion can lead to delamination and, ultimately, premature failure of the coating.

On the Lateral Retreat of Salt Marshes: Field Monitoring in the Venice Lagoon (Italy)

NASA Astrophysics Data System (ADS)

Solari, L.; Bendoni, M.; Mel, R.; Oumeraci, H.; Francalanci, S.; Lanzoni, S.

2014-12-01

Salt marshes are geomorphic structures located in ecotone environments such as lagoon and estuaries, providing lot of ecosystem services to local population. In the last decades they are disappearing due to several factors such as sea level rise, subsidence and edge erosion due to surface waves. The latter is likely the chief mechanism modeling marsh boundaries and leading to the loss of wide marsh areas. In the case of the Venice Lagoon, from the beginning of the last century, the whole salt marsh surface has more than halved and trends indicate that the salt marshes might completely disappear over the next 50 years. Here, we present a field monitoring activity that we are currently carrying out on a retreating salt marsh located in the north part of the Lagoon of Venice (Italy). The marsh is subject to North-East (Bora) wind. Marsh area loss during the last decades has been documented through the comparison of georeferenced aerial photographs showing a retreat rate of the order of 1 m/year. Field measurements started by the end of November 2013 and consist of: salt marsh bank geometry at different cross-sections and wave climate in the lagoon about 30 m in front of the salt marsh. Erosion data are obtained by means of erosion pins located horizontally on the marsh scarp; at higher banks (about 0.9 m), two pins are located along the same vertical direction, for lower banks (about 0.4m), only one pin is employed. Significant wave height has been measured during three storm surges by means of pressure transducers (Pts). The measured wave climate in front of the bank was then put into relationship with the offshore wave climate estimated using wind data (intensity and direction) and bathymetric data. Wind intensity and direction is measured hourly by several measurement stations located in the Lagoon of Venice. In this way, it is possible to extrapolate wave climate hourly at the monitored marsh and calculate the wave power that acted on the bank in a given time interval. Field survey revealed that the main retreating mechanisms are particle by particle erosion alternated to cantilever failures. Preliminary results show a linear relationship between erosion rate and wave energy flux and the existence of a critical threshold for the onset of erosion.

Assessing shoreline exposure and oyster habitat suitability maximizes potential success for sustainable shoreline protection using restored oyster reefs

USGS Publications Warehouse

LaPeyre, Megan K.; Serra, Kayla; Joyner, T. Andrew; Humphries, Austin T.

2015-01-01

Oyster reefs provide valuable ecosystem services that contribute to coastal resilience. Unfortunately, many reefs have been degraded or removed completely, and there are increased efforts to restore oysters in many coastal areas. In particular, much attention has recently been given to the restoration of shellfish reefs along eroding shorelines to reduce erosion. Such fringing reef approaches, however, often lack empirical data to identify locations where reefs are most effective in reducing marsh erosion, or fully take into account habitat suitability. Using monitoring data from 5 separate fringing reef projects across coastal Louisiana, we quantify shoreline exposure (fetch + wind direction + wind speed) and reef impacts on shoreline retreat. Our results indicate that fringing oyster reefs have a higher impact on shoreline retreat at higher exposure shorelines. At higher exposures, fringing reefs reduced marsh edge erosion an average of 1.0 m y−1. Using these data, we identify ranges of shoreline exposure values where oyster reefs are most effective at reducing marsh edge erosion and apply this knowledge to a case study within one Louisiana estuary. In Breton Sound estuary, we calculate shoreline exposure at 500 random points and then overlay a habitat suitability index for oysters. This method and the resulting visualization show areas most likely to support sustainable oyster populations as well as significantly reduce shoreline erosion. Our results demonstrate how site selection criteria, which include shoreline exposure and habitat suitability, are critical to ensuring greater positive impacts and longevity of oyster reef restoration projects.

Establishing a sediment budget in the newly created "Kleine Noordwaard" wetland area in the Rhine-Meuse delta

NASA Astrophysics Data System (ADS)

Christien van der Deijl, Eveline; van der Perk, Marcel; Middelkoop, Hans

2018-03-01

Many deltas are threatened by accelerated soil subsidence, sea-level rise, increasing river discharge, and sediment starvation. Effective delta restoration and effective river management require a thorough understanding of the mechanisms of sediment deposition, erosion, and their controls. Sediment dynamics has been studied at floodplains and marshes, but little is known about the sediment dynamics and budget of newly created wetlands. Here we take advantage of a recently opened tidal freshwater system to study both the mechanisms and controls of sediment deposition and erosion in newly created wetlands. We quantified both the magnitude and spatial patterns of sedimentation and erosion in a former polder area in which water and sediment have been reintroduced since 2008. Based on terrestrial and bathymetric elevation data, supplemented with field observations of the location and height of cut banks and the thickness of the newly deposited layer of sediment, we determined the sediment budget of the study area for the period 2008-2015. Deposition primarily took place in channels in the central part of the former polder area, whereas channels near the inlet and outlet of the area experienced considerable erosion. In the intertidal area, sand deposition especially takes place at low-lying locations close to the channels. Mud deposition typically occurs further away from the channels, but sediment is in general uniformly distributed over the intertidal area, due to the presence of topographic irregularities and micro-topographic flow paths. Marsh erosion does not significantly contribute to the total sediment budget, because wind wave formation is limited by the length of the fetch. Consecutive measurements of channel bathymetry show a decrease in erosion and deposition rates over time, but the overall results of this study indicate that the area functions as a sediment trap. The total contemporary sediment budget of the study area amounts to 35.7×103 m3 year-1, which corresponds to a net area-averaged deposition rate of 6.1 mm year-1. This is enough to compensate for the actual rates of sea-level rise and soil subsidence in the Netherlands.

Aeolis Yardangs

NASA Image and Video Library

2006-01-12

This MGS MOC image shows a group of tapered ridges, known as yardangs, which formed by wind erosion of a relatively easily-eroded material, most likely sedimentary rock or volcanic ash deposits containing some fraction of sand-sized grains

7 CFR 12.1 - General.

Code of Federal Regulations, 2011 CFR

2011-01-01

...— (1) Reduce soil loss due to wind and water erosion; (2) Protect the Nation's long-term capability to produce food and fiber; (3) Reduce sedimentation and improve water quality; and (4) Assist in preserving...

7 CFR 12.1 - General.

Code of Federal Regulations, 2010 CFR

2010-01-01

...— (1) Reduce soil loss due to wind and water erosion; (2) Protect the Nation's long-term capability to produce food and fiber; (3) Reduce sedimentation and improve water quality; and (4) Assist in preserving...

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

Whicker, Jeffrey J; Field, Jason P; Belnap, Jayne

Emission and redistribution of dust due to wind erosion in drylands drives major biogeochemical dynamics and provides important aeolian environmental connectivity at scales from individual plants up to the global scale. Yet, perhaps because most relevant research on aeolian processes has been presented in a geosciences rather than ecological context, most ecological studies do not explicitly consider dust-driven processes. To bridge this disciplinary gap, we provide a general overview of the ecological importance of dust, examine complex interactions between wind erosion and ecosystem dynamics from the plant-interspace scale to regional and global scales, and highlight specific examples of how disturbancemore » affects these interactions and their consequences. Changes in climate and intensification of land use will both likely lead to increased dust production. To address these challenges, environmental scientists, land managers and policy makers need to more explicitly consider dust in resource management decisions.« less

Wave forecasting and longshore sediment transport gradients along a transgressive barrier island: Chandeleur Islands, Louisiana

NASA Astrophysics Data System (ADS)

Georgiou, Ioannis Y.; Schindler, Jennifer K.

2009-12-01

Louisiana barrier islands, such as the chain surrounding the southeast region of the state, are experiencing rapid loss of land area, shoreline erosion, and landward migration due to transgression and in-place drowning, and the landfall of several major hurricanes in the last decade. Observations of migration rates and overall impacts to these barrier islands are poorly understood since they do not respond in a traditional way, such as barrier rollover. This paper aims to verify how wave energy and potential longshore sediment transport trends have influenced the recent evolution of the Chandeleur Islands, by direct comparison with recent observations of migration and erosion trends. The Chandeleur Islands are characterized by a bidirectional transport system, with material moving from the central arc to the flanks. The longshore sediment transport along the barrier islands was calculated after propagation and transformation of waves to breaking (generated using observed winds), and through the use of a common longshore sediment transport formula. Seasonal variations in wind climate produced changes in the transport trends and gradients that agree with migration and rotation patterns observed for this barrier island system. Results suggest that wind dominance produces seasonal oscillations that cause an imbalance in the resulting transport gradients that over time are responsible for higher rates of transport in the northward direction. These results and data from other works verify the evolutionary model previously suggested, and qualitatively confirm the recent observations in asymmetric shoreline erosion.

Field testing, comparison, and discussion of five aeolian sand transport measuring devices operating on different measuring principles

NASA Astrophysics Data System (ADS)

Goossens, Dirk; Nolet, Corjan; Etyemezian, Vicken; Duarte-Campos, Leonardo; Bakker, Gerben; Riksen, Michel

2018-06-01

Five types of sediment samplers designed to measure aeolian sand transport were tested during a wind erosion event on the Sand Motor, an area on the west coast of the Netherlands prone to severe wind erosion. Each of the samplers operates on a different principle. The MWAC (Modified Wilson And Cooke) is a passive segmented trap. The modified Leatherman sampler is a passive vertically integrating trap. The Saltiphone is an acoustic sampler that registers grain impacts on a microphone. The Wenglor sampler is an optical sensor that detects particles as they pass through a laser beam. The SANTRI (Standalone AeoliaN Transport Real-time Instrument) detects particles travelling through an infrared beam, but in different channels each associated with a particular grain size spectrum. A procedure is presented to transform the data output, which is different for each sampler, to a common standard so that the samplers can be objectively compared and their relative efficiency calculated. Results show that the efficiency of the samplers is comparable despite the differences in operating principle and the instrumental and environmental uncertainties associated to working with particle samplers in field conditions. The ability of the samplers to register the temporal evolution of a wind erosion event is investigated. The strengths and weaknesses of the samplers are discussed. Some problems inherent to optical sensors are looked at in more detail. Finally, suggestions are made for further improvement of the samplers.

Wind and Water?

NASA Technical Reports Server (NTRS)

2005-01-01

[figure removed for brevity, see original site] Context image for PIA03284 Wind and Water?

The deposits within this crater show evidence of erosion by both wind and water. The region outside the crater is dominated by wind erosion.

Image information: VIS instrument. Latitude 1.4N, Longitude 204.1E. 18 meter/pixel resolution.

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.

Observed Changes at Viking Lander 1

NASA Technical Reports Server (NTRS)

Moore, H. J.

1985-01-01

A local dust storm raged in Chryse Planitia, Mars, in June 1981. The changes wrought in the vicinity of the lander (Mutch Memorial Station) by this storm sometime near Sol 1742 were partly described previously. Here, changes related to the storm are itemized, evidence for wind directions during the peak of the storm are cited, and two observations unrelated to the storm are noted. The observations suggest that the eroding winds of the Sol 1742 storm were more easterly (N. 35 deg to 90 deg E.) than those (N. 5 deg to 11 deg E.) that formed the large wind tails; and fragments in erosional residues are 0.7 cm and larger, but smaller ones may be present. Some fragments 0.4 to 0.5 cm and smaller were somehow removed, at least locally; wind speeds of the 1742 local storm were probably greater than those of a previous local dust storm (25 to 30 m/s) that occurred during the same season on Sol 423 because the earlier storm did not alter the surface; the major, if not entire, amount of erosion by the storm occurred between Sols 1728 and 1757; and erosion chiefly occurred where the surface configuration and material properties were altered by the lander and its sampler.

Quantification Of Erosion Rates Of Agriculturally Used Soils By Artificial

NASA Astrophysics Data System (ADS)

Jha, Abhinand

2010-05-01

0.0.1 1. Introduction to soil erosion measurement by radionuclides Soil erosion by water, wind and tillage affects both agriculture and the natural environment. Studying this phenomenon would be one of the advancements in science. Soil erosion occurs worldwide and since the last two decades it has been a main topic of discussion all over the world. The use of environmental radionuclides such as 90Sr, 137Cs to study medium term soil erosion (40 yrs) started in the early 1990's. Using these new techniques better knowledge about erosion can be gained and this knowledge can be implemented for erosion risk management. The erosion and sedimentation study by using man-made and natural radioisotopes is a key technique, which has developed over the past 30 years. Fallout 137Cs and Cosmogenic 7Be are radionuclides that have been used to provide independent measurements of soil-erosion and sediment-deposition rates and patterns [1] [2] [3] [4]. Erosion measurements using radionuclides 137Cs, 7Be Caesium-137 from atmospheric nuclear-weapons tests in the 1950s and 1960s (Fig.1) is a unique tracer of erosion and sedimentation, since there are no natural sources of 137Cs. Unique events such as the Chernobyl accident in April 1986 caused regional dispersal of 137Cs that affects the total global deposition budget. This yearly pattern of fallout can be used to develop a chronology of deposition horizons in lakes, reservoirs, and floodplains. 137Cs can be easily measured by gamma spectroscopy. Using 137Cs is a fast and cheap method to study erosion-deposition processes compared to the traditional methods like silt bags. PIC Figure 1: Global 137Cs fallout (Modified from SAAS Bulletin 353, Part E, DDR, 1986) When 137Cs, 7Be reach the soil surface by wet and dry deposition, they are quickly and strongly adsorbed by ion exchange and are essentially non exchangeable in most environments. Each radionuclide is distributed differently in the soil because of differences in half-lives (30 yrs for 137Cs and 53 days for 7Be), delivery rates, delivery histories, and land use (Fig. 2). An Physical processes, such as water and wind, are the dominant factors moving 137Cs, 7Be tagged soil particles within and between landscape compartments. PIC Figure 2: Generalized sketch illustrating the distributions of 137Cs and 7Be in tilled and undisturbed soils 2 Erosion study at Young Moraine regions of Germany Recently, a study had been performed to evaluate erosion rates in a typical pattern of landscapes in the Young Moraine regions of North-East Germany [5]. The 137Cs concentrations were measured at selected sampling points of various study sites. Among the areas selected for sampling was Basedow, which is a cultivated area, situated north of Berlin. During a master thesis study at university of Bremen in the academic year 2008-2009 [6] a second sampling campaign was performed at the same study site and 137Cs and 7Be concentrations were measured. Two mathematical models (a proportional model and a mass balance model) were applied to estimate erosion or deposition rates giving a distinction between uncultivated or essentially undisturbed soils and cultivated or soils under permanent pasture (Fig.3A). An improved depositional model was developed during this study. The simulation results from this model are presented in Fig.4. Due to the half-life (53.2 days) of 7Be, a mass balance model was developed and used to calculate erosion rates from 7Be (Fig.3B). PIC Figure 3: A: Erosion rates for 137Cs calculated by mass balance model. B: Erosion rates calculated with mass balance model using the 7Be data at Basedow (2008). The results verify that there is long term erosion as a result of wind, water and agricultural practices. The annual erosion rates at Basedow calculated using a mass balance and a proportional model were in the range between 30-50 t ha-1yr-1. These values were comparable to the erosion rates calculated in the previous study [5] by the models mentioned above. PIC Figure 4: Profiles of sediment calculated for different erosion rates by Cs-137 within the ploughed soil 3 Conclusions and outlook Erosion rates for agricultural soils at Young Moraine regions of North-East Germany were determined by using two radionuclides, 137Cs and 7Be. In combination, the two radionuclides provide a valuable means of investigating soil erosion and assessing erosion risk in the study area. Potentials and limitations of the erosion measurement techniques using radiotracers are discussed in this study. The models used to quantify erosion rates using 137Cs and 7Be were studied. Erosion rates calculated by theses models are difficult to measure over a period of 50 years. A validation of these erosion rates for the time period (50 years) used in the 137Cs-based models will give a new perspective to the use of soil erosion modeling. Most of the regions in India are suffering from high erosion rates [7]. By using the new techniques in erosion quantification the land management practices can be improved and the erosion risk can be reduced in India.

Solid particle erosion of polymers and composites

NASA Astrophysics Data System (ADS)

Friedrich, K.; Almajid, A. A.

2014-05-01

After a general introduction to the subject of solid particle erosion of polymers and composites, the presentation focusses more specifically on the behavior of unidirectional carbon fiber (CF) reinforced polyetheretherketone (PEEK) composites under such loadings, using different impact conditions and erodents. The data were analyzed on the basis of a newly defined specific erosive wear rate, allowing a better comparison of erosion data achieved under various testing conditions. Characteristic wear mechanisms of the CF/PEEK composites consisted of fiber fracture, matrix cutting and plastic matrix deformation, the relative contribution of which depended on the impingement angles and the CF orientation. The highest wear rates were measured for impingement angles between 45 and 60°. Using abrasion resistant neat polymer films (in this case PEEK or thermoplastic polyurethane (TPU) ones) on the surface of a harder substrate (e.g. a CF/PEEK composite plate) resulted in much lower specific erosive wear rates. The use of such polymeric films can be considered as a possible method to protect composite surfaces from damage caused by minor impacts and erosion. In fact, they are nowadays already successfully applied as protections for wind energy rotor blades.

Windblown Dust Deposition Forecasting and Spread of Contamination around Mine Tailings.

PubMed

Stovern, Michael; Guzmán, Héctor; Rine, Kyle P; Felix, Omar; King, Matthew; Ela, Wendell P; Betterton, Eric A; Sáez, Avelino Eduardo

2016-02-01

Wind erosion, transport and deposition of windblown dust from anthropogenic sources, such as mine tailings impoundments, can have significant effects on the surrounding environment. The lack of vegetation and the vertical protrusion of the mine tailings above the neighboring terrain make the tailings susceptible to wind erosion. Modeling the erosion, transport and deposition of particulate matter from mine tailings is a challenge for many reasons, including heterogeneity of the soil surface, vegetative canopy coverage, dynamic meteorological conditions and topographic influences. In this work, a previously developed Deposition Forecasting Model (DFM) that is specifically designed to model the transport of particulate matter from mine tailings impoundments is verified using dust collection and topsoil measurements. The DFM is initialized using data from an operational Weather Research and Forecasting (WRF) model. The forecast deposition patterns are compared to dust collected by inverted-disc samplers and determined through gravimetric, chemical composition and lead isotopic analysis. The DFM is capable of predicting dust deposition patterns from the tailings impoundment to the surrounding area. The methodology and approach employed in this work can be generalized to other contaminated sites from which dust transport to the local environment can be assessed as a potential route for human exposure.

Windblown Dust Deposition Forecasting and Spread of Contamination around Mine Tailings

PubMed Central

Stovern, Michael; Guzmán, Héctor; Rine, Kyle P.; Felix, Omar; King, Matthew; Ela, Wendell P.; Betterton, Eric A.; Sáez, Avelino Eduardo

2017-01-01

Wind erosion, transport and deposition of windblown dust from anthropogenic sources, such as mine tailings impoundments, can have significant effects on the surrounding environment. The lack of vegetation and the vertical protrusion of the mine tailings above the neighboring terrain make the tailings susceptible to wind erosion. Modeling the erosion, transport and deposition of particulate matter from mine tailings is a challenge for many reasons, including heterogeneity of the soil surface, vegetative canopy coverage, dynamic meteorological conditions and topographic influences. In this work, a previously developed Deposition Forecasting Model (DFM) that is specifically designed to model the transport of particulate matter from mine tailings impoundments is verified using dust collection and topsoil measurements. The DFM is initialized using data from an operational Weather Research and Forecasting (WRF) model. The forecast deposition patterns are compared to dust collected by inverted-disc samplers and determined through gravimetric, chemical composition and lead isotopic analysis. The DFM is capable of predicting dust deposition patterns from the tailings impoundment to the surrounding area. The methodology and approach employed in this work can be generalized to other contaminated sites from which dust transport to the local environment can be assessed as a potential route for human exposure. PMID:29082035

Comparison of conventional and bio-treated methods as dust suppressants.

PubMed

Naeimi, Maryam; Chu, Jian

2017-10-01

Dust is an environmental, geotechnical, health, and economical hazard. Fugitive dust emanating along transportation systems such as roads, railways, and airports especially can have significant impacts on health, safety, material loss, cost of maintenance, and interfere with the facilities. Quantitative studies on the effectiveness of the proper dust palliatives and their environmental impact have been studied with a number of biological and chemical methods. The objective of this study was to establish a method for using the microbial Induced calcium carbonate precipitation (MICP) approach to reduce the percent of mass loss against erosive force of wind regarding to the concentration and characteristics of aggregate used, climate, and traffic amounts. The results of this study showed that the required precipitation for dust control of sand by 70% is less than 15 g CaCO 3 /m 2 between sand grains in bio-treated sand. The wind tunnel test results of this study also indicate that the effectiveness of the bio-treatment method for dust control depends on many variables, such as the percent of precipitated calcium carbonate and tensile strength.

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

USGS Publications Warehouse

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

2011-01-01

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

Controls on drainage divide migration in the northern Sierras Pampeanas assessed through morphometric indicators

NASA Astrophysics Data System (ADS)

Seagren, E. G.; Schoenbohm, L. M.

2017-12-01

Drainage reorganization, primarily through progressive divide migration leading to discrete stream captures, is increasingly recognized as a common phenomenon during mountain-building events. This drainage rearrangement reflects complex interactions between tectonics, climate, and lithology, and can fundamentally change erosion and sedimentation patterns; therefore, determining the spatial extent and potential controls of divide migration is vital to understanding the topographic evolution of orogenic landscapes. Both geomorphic and morphometric evidence can be used to identify such drainage reorganization. The northern Sierras Pampeanas is an ideal location in which to study divide migration as limited glaciation and low out-of-channel erosion rates preserve evidence of reorganization. Additionally, several ranges in the region, such as Sierra de las Planchadas, exhibit geomorphic evidence of drainage rearrangement, including wind gaps and hairpin turns. Using ArcGIS, LSDTopoTools, and TopoToolbox, we conducted a systematic analysis of the spatial distribution of three morphometric indicators of divide migration: χ, Mx, and local headwater relief. Local `hotspots' undergoing drainage divide migration were identified using spatial autocorrelation and clustering methods - Gi* and Moran's I. Using spatial regression analysis, we assessed the potential controls of lithology, modern TRMM precipitation rates, and tectonics over divide migration. Preliminary results suggest broad westward migration of main drainage divides, following both the orographic precipitation gradient and regional slope.

Patterns of sediment dispersion coastwise the State of Bahia - Brazil.

PubMed

Bittencourt; Dominguez; Martin; Silva

2000-06-01

Using the average directions of the main wave-fronts which approach the coast of Bahia State - coinciding with that of the main wind occurring in the area - and of their periods, we define a wave climate model based on the construction of refraction diagrams. The resulting model of sediment transport was able to reproduce, in a general way, the sediment dispersion patterns furnished by geomorphic indicators of the littoral drift. These dispersion patterns control the generation of different types of sediment accumulations and of coastal stretches under erosion. We demonstrate that the presence of the Abrolhos and Corumbaú Point coral reefs is an important factor controlling the sediment dispersion patterns, since them act as a large protection against the waves action.

Comprehensive evaluation of land quality basing on 3S technology and farmers' survey: A case study in Crisscross Region of Wind-drift Sand Regions along the Great Wall and Loess Plateau

NASA Astrophysics Data System (ADS)

Zhang, Yan-yu; Wang, Jing; Shi, Yan-xi; Li, Yu-huan; Lv, Chun-yan

2005-10-01

The Crisscross Region of Wind-drift Sand Regions along the Great Wall and Loess Plateau locates in southern Ordos Plateau and northern Chinese Loess Plateau, where wind erosion and water erosion coexist and specified environmental and socio-economic factors, especially human activities induce serious land degradation. However, there are only a few studies provide an overall assessment consequences. Integrated land quality assessment considering impacts of soil, topography, vegetation, environmental hazards, social-economic factors and land managements are imperative to the regional sustainable land managements. A pilot study was made in Hengshan County (Shanxi Province) with the objective of developing comprehensive land quality evaluation model integrating data from farmers' survey and Remote Sensing. Surveys were carried out in 107 households of study area in 2003 and 2004 to get farmers' perceptions of land quality and to collect correlative information. It was found out that farmers evaluated land quality by slope, water availability, soil texture, yields, amount of fertilizer, crop performance, sandy erosion degree and water erosion degree. Scientists' indicators which emphasize on getting information by RS technology were introduced to reflecting above indicators information for the sake of developing a rapid, efficient and local-fitted land quality assessment model including social-economic, environmental and anthropogenic factors. Data from satellite and surveys were integrated with socio-economic statistic data using geographical information system (GIS) and three indexes, namely Production Press Index (PPI), Land State Index (LSI) and Farmer Behavior Index (FBI) were proposed to measure different aspects of land quality. A model was further derived from the three indexes to explore the overall land quality of the study area. Results suggest that local land prevalently had a poor quality. This paper shows that whilst the model was competent for its work in the study area and evaluation results would supply beneficial information for management decisions.

Airborne and spaceborne lasers for terrestrial geophysical sensing; Proceedings of the Meeting, Los Angeles, CA, Jan. 14, 15, 1988

NASA Technical Reports Server (NTRS)

Allario, Frank (Editor)

1988-01-01

The present conference on airborne and spaceborne remote sensing laser applications discusses topics in atmospheric and geophysical sciences-related sensors, lidar and DIAL component and subsystem technologies, and coherent laser experiments and semiconductor laser technologies. Attention is given to airborne lidar measurement of aerosols, a ground-based injection-locked pulsed TEA laser for wind measurements, chemical/biological agent standoff detection methods, lidars for wind shear erosion, laser tuning to selected gas absorption lines in the atmosphere, the NASA lidar-in-space technology experiment, and the Laser Atmospheric Wind Sounder.

How will wind and water erosion change in drylands in the future?

NASA Astrophysics Data System (ADS)

Okin, G. S.; Sala, O.; Vivoni, E. R.

2017-12-01

Drylands are characterized as much by high spatial and temporal variability as they are by low precipitation. Cover that is patchy at multiple scales allows connectivity for wind and water transport. Vegetation dynamics at interannual scales occurs in the context of community change (including woody encroachment) at decadal scales. Periods of drought alternate with relatively wet periods. Future predictions for the world's drylands are that many will become more arid, but near all will experience greater climate variability. This work explores how future variability will affect transport by wind and water, both of which are crucial elements of biotic-abiotic feedbacks that control community change in drylands. This work is based on long-term observations from the Jornada Long Term Ecological Research (LTER), but with lessons that are applicable elsewhere. We find strong relationships between vegetation community, precipitation and aeolian transport related to changes in connectivity. We further identify strong, scale-dependent relationships between precipitation and runoff. Thus, aeolian transport decreases with increasing annual precipitation and transport by water increases with annual precipitation, with the combined effect that increased variability in annual precipitation is likely to increase both water and wind transport. The consequence of this is that feedbacks associated with community change are likely to strengthen in the future.

Shaping the Landscape.

ERIC Educational Resources Information Center

Naturescope, 1987

1987-01-01

Provides background information on various agents that change the landscape. Includes teaching activities on weathering, water, wind and ice erosion, plate tectonics, sedimentation, deposition, mountain building, and determining contour lines. Contains reproducible handouts and worksheets for two of the activities. (TW)

Improving the performance of roadside vegetation.

DOT National Transportation Integrated Search

2011-02-01

Vegetation along roadways can be aesthetically pleasing and helps to stabilize the soil, which reduces wind-blown soil : and soil erosion. While products containing chloride salts have proven to be very effective in helping to provide safe road : sur...

Seeding and planting hardwoods

Treesearch

J. W. Van Sambeek; Robert D. Williams

1989-01-01

Objectives of forest plantings can include one or more of the following: 1. Produce high quality timber and improve stand composition 2. Improve wildlife habitat 3. Reforest land not suited for agriculture 4. Arrest soil and wind erosion 5. Enhance esthetics

Gully annealing by fluvially-sourced Aeolian sand: remote sensing investigations of connectivity along the Fluvial-Aeolian-hillslope continuum on the Colorado River

USGS Publications Warehouse

Sankey, Joel B.; East, Amy E.; Collins, Brian D.; Caster, Joshua J.

2015-01-01

Processes contributing to development of ephemeral gully channels are of great importance to landscapes worldwide, and particularly in dryland regions where soil loss and land degradation from gully erosion pose long-term, land-management problems. Whereas gully formation has been relatively well studied, much less is known of the processes that anneal gullies and impede their growth. This work investigates gully annealing by aeolian sediment, along the Colorado River downstream of Glen Canyon Dam in Glen, Marble, and Grand Canyons, Arizona, USA (Figure 1). In this segment of the Colorado River, gully erosion potentially affects the stability and preservation of archaeological sites that are located within valley margins. Gully erosion occurs as a function of ephemeral, rainfall-induced overland flow associated with intense episodes of seasonal precipitation. Measurements of sediment transport and topographic change have demonstrated that fluvial sand in some locations is transported inland and upslope by aeolian processes to areas affected by gully erosion, and aeolian sediment activity can be locally effective at counteracting gully erosion (Draut, 2012; Collins and others, 2009, 2012; Sankey and Draut, 2014). The degree to which specific locations are affected by upslope wind redistribution of sand from active channel sandbars to higher elevation valley margins is termed “connectivity”. Connectivity is controlled spatially throughout the river by (1) the presence of upwind sources of fluvial sand within the contemporary active river channel (e.g., sandbars), and (2) bio-physical barriers that include vegetation and topography that might impede aeolian sediment transport. The primary hypothesis of this work is that high degrees of connectivity lead to less gullying potential.

Shoreline erosion at selected areas along Lake Sharpe on the Lower Brule Reservation in South Dakota, 1966–2015

USGS Publications Warehouse

Thompson, Ryan F.; Stamm, John F.

2018-06-21

The Lower Brule Reservation in central South Dakota is losing land because of shoreline erosion along Lake Sharpe, a reservoir on the Missouri River, which has caused detrimental effects for the Lower Brule Sioux Tribe including losses of cultural sites, recreation access points, wildlife habitat, irrigated cropland, and landmass. To better understand and quantify shoreline erosion, the Lower Brule Sioux Tribe and the U.S. Geological Survey cooperated on a series of data-collection efforts and study of shoreline erosion along Lake Sharpe. Data collected or compiled for 1966–2015 were used to describe and quantify shoreline erosion along Lake Sharpe. The progression of shoreline erosion near the community of Lower Brule, South Dakota, was tracked by comparing current or recent aerial imagery with existing historical maps. At 33 evaluation lines along a 7-mile reach of Lake Sharpe shoreline near Lower Brule, cumulative change of shoreline from 1966 to 2010 ranged from about −224 feet of deposition to 770 feet of erosion.Photographic and location data were collected for this study to understand the processes affecting erosion and estimate erosion rates. Photographs were collected only in the 7-mile reach near Lower Brule, but locations of the bank over time were collected at the 7-mile reach and two additional reaches within the Lower Brule Reservation. Global navigation satellite system equipment was used in real-time kinematic mode to collect bank locations along three reaches of interest. Reach-length data were collected four times between November 2011 and November 2012. A small, unmanned aerial system (drone) was used to capture digital video along the shoreline of the 7-mile reach.Water-level fluctuations contribute to the number of wet-dry cycles experienced by the soils at the shoreline or bank. The soils present under the current (2017) location of the reservoir are predominantly terrace alluvium, consisting of sand and silt. Detailed soils data for Lyman County indicate that the dominant soil type along the southern part of the shoreline in the 7-mile reach is Bullcreek clay. Weather within the study area can affect the erosion rate. Air temperature can potentially affect erosion rates by freezing and thawing water and soils. Mean hourly wind speeds vary somewhat throughout the year but averaged 13.3 miles per hour. The direction of prevailing winds near Lower Brule indicates that there are several miles of fetch to build large waves.Annual erosion rates calculated or measured throughout this study varied by location. Long-term annual average erosion rates of the 7-mile reach, as calculated by image analysis, ranged from −5.1 feet per year (deposition) to 17.5 feet per year (erosion). Short-term annual erosion rates measured using global navigation satellite system equipment during 2010–12 ranged from about 0 to 31.7 feet per year for the 7-mile reach. Existing scour countermeasures have been effective variably. Fieldstone rip-rap seems to have stabilized the shoreline, whereas tree strips paralleling the shoreline seem to have slowed erosion.

Sea-cliff erosion at Pacifica, California caused by 1997/98 El Niño storms

USGS Publications Warehouse

Snell, Charles B.; Lajoie, Kenneth R.; Medley, Edward W.

2000-01-01

Twelve homes were constructed in 1949 at the top of a sea cliff along Esplanade Drive in the City of Pacifica, located on the northern coast of San Mateo County, California. The rear yards of those properties were bounded by an approximately 20-meter (70-foot) high cliff that has retreated episodically at an average rate of 0.5 to 0.6 meter (1.5 to 2 feet) per year over the past 146 years. During the heavy storms of the 1997/1998 El Niño winter, a severe episode of cliff retreat undermined seven homes and threatened three others. All ten homes were condemned and demolished by the City of Pacifica. In this study we analyze geologic, tide, wave, rainfall and wind data in an attempt to determine the causes of this most recent erosion event. We identify the following possible contributory causes of the cliff retreat: 1) wave-induced undercutting of the cliff landward of an old revetment, 2) reduction in beach width over time, 3) reduction in cliff-face stability owing to infiltration from heavy rains, 4) erosion of the cliff face by groundwater piping, and 5) wind-induced erosion of loose dune sand at the top of the cliff. While these factors may explain the retreat of the cliff below the twelve homes along Esplanade Drive, the question remains as to why other geologically similar sites in the region were not severely eroded during the 1997/1998 El Niño winter.

Origin and Evolution of the Layered Sulfate-Rich Rocks in Meridiani Planum, Mars

NASA Astrophysics Data System (ADS)

Arvidson, R. E.

2007-12-01

Opportunity rover observations show that Meridiani Planum has extensive exposures of sulfate-rich dirty sandstones partially covered by a mix of wind-blown basaltic sand, dust, and a lag deposit of 1 to 5 mm diameter hematitic concretions. The dirty sandstones are interpreted to have formed in an acid-sulfate evaporative lacustrine system that left behind sulfate-rich muds with a siliciclastic component. Erosion by wind and water produced sandstones that were then cemented and diagenetically altered by rising groundwater. Subsequent wind erosion of these deposits and associated advection of basaltic sand onto the outcrops produced the surfaces encountered during the rover's traverses. On a regional scale these sulfate-rich deposits are up to several kilometers in thickness, extend over several hundred thousand square kilometers, and unconformably overlie the fluvially dissected Noachian cratered terrain. Both OMEGA and CRISM hyperspectral data show clear evidence for the presence of phyllosilicate minerals in the cratered terrains adjacent to the sulfate deposits, but not within the sulfate section proper. The ensemble of evidence indicates a change in Meridiani Planum from fluvial erosion and formation of phyllosilicate minerals to deposition of evaporite deposits associated with an acid-sulfate aqueous system. This change is interpreted to be due to a major climatic shift in which a relatively vigorous hydrologic system with extensive neutral rain and snowfall changed to more arid conditions in which a regional-scale acid sulfate groundwater system emerged in Meridiani Planum with enough of a hydrostatic head to produce and retain 1 to 3 km of sulfate-rich deposits.

Implications of Biofuel-Induced Land Use Change and Management on Irrigated Agriculture in the Texas High Plains

NASA Astrophysics Data System (ADS)

Ale, S.; Chen, Y.; Rajan, N.

2016-12-01

Texas High Plains (THP) is one of the important cotton (Gossypium hirsutum L.) growing regions in the US. Agriculture in the THP faces several challenges from declining groundwater levels and deteriorating groundwater quality in the underlying Ogallala Aquifer, and recurring droughts and severe wind erosion. Groundwater conservation districts in the THP have started setting up limits on annual allowable groundwater pumping for irrigation. Introducing cover crops in to the cotton production systems in the THP and/or changing land use from cotton to perennial bioenergy crops could not only address the above challenges, but also assist in meeting the national biofuel target. The overall goal of this study is to assess the implications of biofuel-indced land use managemt (growing winter wheat as a cover crop along with cotton) and land use change (replacing cotton with Alamo switchgrass (Panicum virgatum L.) and Miscanthus (Miscanthus giganteus)) on hydrology, water quality, wind erosion and biofuel production potential in the Double Mountain Fork Brazos watershed in the THP using the Agricultural Policy/Environmental eXtender (APEX) model. Results showed that, in comparison to the baseline (cotton monoculture) scenario, the average annual wind erosion reduced by 59% and 37% in irrigated and dryland areas, respectively, when winter wheat was grown as a cover crop along with cotton under the current 18-inch groundwater pumping restriction set up by the High Plains Water District. In addition, winter wheat produced about 2.6 and 2.0 Mg ha-1 of biomass for biofuel purposes under the irrigated and dryland conditions, respectively. Furthermore, the total nitrogen (TN) load and nitrate-nitrogen (NO3-N) leaching decreased by more than 43% and 73%, respectively, under the cover crop scenario. The land use change from cotton to switchgrass (in irrigated areas) and Miscanthus (in dryland areas) decreased the TN load, NO3-N leaching and wind erosion by more than 89% relative to the baseline. Under the restrictions on groundwater use, when compared to single harvest, multiple harvests of perennial bioenergy crops (two- and three-harvests in case of switchgrass and Miscanthus, respectively) were found to be better in terms of biomass production (> 20 Mg ha-1), and protection of groundwater and soil quality.

Pyrogenic carbon erosion: implications for stock and persistence of pyrogenic carbon in soil

NASA Astrophysics Data System (ADS)

Abney, Rebecca B.; Berhe, Asmeret Asefaw

2018-03-01

Pyrogenic carbon (PyC) constitutes an important pool of soil organic matter, particularly for its reactivity and because of its assumed long residence times in soil. In the past, research on the dynamics of PyC in the soil system has focused on quantifying stock and mean residence time of PyC in soil, as well as determining both PyC stabilization mechanisms and loss pathways. Much of this research has focused on decomposition as the most important loss pathway for PyC from soil. However, the low density of PyC and its high concentration on the soil surface after fire indicates that a significant proportion of PyC formed or deposited on the soil surface is likely laterally transported away from the site of production by wind and water erosion. Here, we present a synthesis of available data and literature to compare the magnitude of the water-driven erosional PyC flux with other important loss pathways, including leaching and decomposition, of PyC from soil. Furthermore, we use a simple first-order kinetic model of soil PyC dynamics to assess the effect of erosion and deposition on residence time of PyC in eroding landscapes. Current reports of PyC mean residence time (MRT) range from 250 to 660 years. Using a specific example-based model system, we find that ignoring the role of erosion may lead to the under- or over-estimation of PyC MRT on the centennial time scale. Furthermore, we find that, depending on the specific landform positions, timescales considered, and initial concentrations of PyC in soil, ignoring the role of erosion in distributing PyC across a landscape can lead to discrepancies in PyC concentrations on the order of several hundred g PyC m-2. Erosion is an important PyC flux that can act as a significant control on the stock and residence time of PyC in the soil system.

Dust dynamics in off-road vehicle trails: Measurements on 16 arid soil types, Nevada, USA.

PubMed

Goossens, Dirk; Buck, Brenda

2009-08-01

Soil analyses and measurements with the Portable In Situ Wind Erosion Laboratory (PI-SWERL) were conducted on 16 soil types in an area heavily affected by off-road vehicle (ORV) driving. Measurements were performed in ORV trails as well as on undisturbed terrain to investigate how ORV driving affects the vulnerability of a soil to emit PM10 (particles<10microm), during the driving as well as during episodes of wind erosion. Particular attention is paid to how the creation of a new trail affects those properties of the topsoil that determine its capability to emit PM10. Also, recommendations are given for adequate management of ORV-designed areas. The type of surface (sand, silt, gravel, drainage) is a key factor with respect to dust emission in an ORV trail. Trails in sand, defined in this study as the grain size fraction 63-2000microm, show higher deflation thresholds (the critical wind condition at which wind erosion starts) than the surrounding undisturbed soil. Trails in silt (2-63microm) and in drainages, on the other hand, have lower deflation thresholds than undisturbed soil. The increase in PM10 emission resulting from the creation of a new ORV trail is much higher for surfaces with silt than for surfaces with sand. Also, the creation of a new trail in silt decreases the supply limitation in the top layer: the capacity of the reservoir of emission-available PM10 increases. For sand the situation is reversed: the supply limitation increases, and the capacity of the PM10 reservoir decreases. Finally, ORV trails are characterized by a progressive coarsening of the top layer with time, but the speed of coarsening is much lower in trails in silt than in trails in sand or in drainages. The results of this study suggest that, to minimize emissions of PM10, new ORV fields should preferably be designed on sandy terrain rather than in silt areas or in drainages.

Multi-scale variability of storm Ophelia 2017: The importance of synchronised environmental variables in coastal impact.

PubMed

Guisado-Pintado, Emilia; Jackson, Derek W T

2018-07-15

Low frequency, high magnitude storm events can dramatically alter coastlines, helping to relocate large volumes of sediments and changing the configuration of landforms. Increases in the number of intense cyclones occurring in the Northern Hemisphere since the 1970s is evident with more northward tracking patterns developing. This brings added potential risk to coastal environments and infrastructure in northwest Europe and therefore understanding how these high-energy storms impact sandy coasts in particular is important for future management. This study highlights the evolution of Storm (formally Hurricane) Ophelia in October 2017 as it passed up and along the western seaboard of Ireland. The largest ever recorded Hurricane to form in the eastern Atlantic, we describe, using a range of environmental measurements and wave modelling, its track and intensity over its duration whilst over Ireland. The impact on a stretch of sandy coast in NW Ireland during Storm Ophelia, when the winds were at their peak, is examined using terrestrial laser scanning surveys pre- and post-storm to describe local changes of intertidal and dune edge dynamics. During maximum wind conditions (>35 knots) waves no >2m were recorded with an oblique to parallel orientation and coincident with medium to low tide (around 0.8m). Therefore, we demonstrate that anticipated widespread coastal erosion and damage may not always unfold as predicted. In fact, around 6000m 3 of net erosion occurred along the 420m stretch of coastline with maximum differences in beach topographic changes of 0.8m. The majority of the sediment redistribution occurred within the intertidal and lower beach zone with some limited dune trimming in the southern section (10% of the total erosion). Asynchronous high water (tide levels), localised offshore winds as well as coastline orientation relative to the storm winds and waves plays a significant role in reducing coastal erosional impact. Copyright © 2018 Elsevier B.V. All rights reserved.

Human-induced landscape dynamics in South Brandenburg - findings from different geoarchives

NASA Astrophysics Data System (ADS)

Raab, Thomas; Raab, Alexandra; Nicolay, Alexander; Takla, Melanie; Hirsch, Florian; Schneider, Anna; Rösler, Horst; Bönisch, Eberhard

2014-05-01

South Brandenburg is the central part of the North European Lowland (NEL) extending as a plain landscape from the North and Baltic Sea to the foothills of the Central European Highlands and reaching from the Netherlands to Poland. Since many decades lignite opencast mines have been operating in this region which is known as the Lusatian mining district. The total land demand in Lusatia is about 852 square kilometres and mining will continue for many more years or even decades. Large-scale outcrops resulting from these mining activities are excellent archives to study the younger Earth's history. The scope of our research in open cast mines is to reconstruct the Late Quaternary landscape development and to distinguishing natural from anthropogenic forcing and processes. In more detail, the aims are to identify and to quantify the impact of past land uses, i.e. changes of vegetation, landforms and soils induced by agriculture and/or forestry. Here, we are presenting latest results from our research and review important findings giving novel insights into man-induced environmental changes in Lusatia within the past thousands years and thus improving the general understanding of Late Quaternary landscape dynamics. Direct legacies of historical farming can be found in form of hook ploughs as well as ridge and furrow systems. Several sites have been documented within the last decades giving us nowadays a quite solid picture of the type and of the spatio-temporal dimension the former agricultural system. During years Airborne Laser Scanning (ALS) data help us to identify ridge and furrow systems under forest canopy and thus to support these findings. Sometimes hook ploughs and ridge and furrow systems are found buried under aeolian sediments proving a causal connection between farming and wind erosion. Obviously the well-drained, sandy and humus-poor soils are prone to dry out easily by agricultural overuse and thus can be eroded by wind. The flat landscape and missing higher/denser vegetation enhance wind speeds and advantage wind erosion, too. In fact, these phenomena can be observed also today and very probably as a consequence of the same reasons as in historical times - mainly (i) overuse or not adapted agricultural practice, (ii) temporal edaphic drought, (iii) less vegetation or wind breaks, and (iv) weather anomalies with high wind speeds. Comparing our results with other studies in Central Europe we can make some generalizable contributions but we also must state regional differences and specific characteristics caused by the local setting. (i) As proven in other regions, during the Holocene and principally since the onset of agriculture in the Neolithic, the anthropogenic impetus must be considered as the crucial factor to initialize aeolian geomorphodynamics. (ii) Intensification of soil erosion coincides with agricultural land use during the Slavic Middle Ages. (iii) As we see similar processes of wind erosion nowadays we can conclude that in principle the feedbacks between human impact and landscape development (in sense of soil and landform evolution) can be compared between historical and modern times.

Sedimentology and preservation of aeolian sediments on steep terrains: Incipient sand ramps on the Atacama coast (northern Chile)

NASA Astrophysics Data System (ADS)

Ventra, Dario; Rodríguez-López, Juan Pedro; de Boer, Poppe L.

2017-05-01

The origin of topographically controlled aeolian landforms in high-relief settings is difficult to synthesize under general models, given the dependence of such accumulations on local morphology. Quaternary sand ramps have been linked to palaeoclimate, regional geomorphology and wind patterns; however, controls on the early development and preservation of such landforms are poorly known. This study describes the morphology and sedimentology of complex sedimentary aprons along steep coastal slopes in the Atacama Desert (Chile). Direct slope accessibility and continuous stratigraphic exposures enable comparisons between active processes and stratigraphic signatures. Stratigraphic facies distribution and its links with patterns of aeolian deposition show that the preservation of wind-laid sediments depends on the morphology and processes of specific slope sectors. The spatial organization of runoff depends on bedrock configuration and directly controls the permanence or erosion of aeolian sediment. The occurrence of either water or mass flows depends on the role of aeolian fines in the rheology of flash floods. In turn, the establishment of a rugged surface topography controlled by patterns of mass-flow deposition creates local accommodation for aeolian fines, sustaining the initial aggradation of a colluvial-aeolian system. By contrast, slopes subject to runoff develop a thin, extensive aeolian mantle whose featureless surface is subject mostly to sediment bypass down- and across-slope; the corresponding stratigraphic record comprises almost exclusively thin debris-flow and sheetflood deposits. Slope morphology and processes are fundamental in promoting or inhibiting aeolian aggradation in mountain settings. Long-term sand-ramp construction depends on climate and regional topography, but the initial development is probably controlled by local geomorphic factors. The observed interactions between wind and topography in the study area may also represent a process analogue for the interpretation of similar geomorphic features on Mars.

Anthropogenic Environments

USDA-ARS?s Scientific Manuscript database

Aerosols or airborne dust can originate from sources unrelated to anthropogenic activity but may also be initiated or exacerbated by anthropogenic actions. Anthropogenic dust refers to dust activity (emission and suppression) that is present due to human activity. Wind erosion in the U.S. is a sign...

40 CFR 265.223 - Containment system.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 265.223 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) INTERIM STATUS STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL..., such as grass, shale, or rock, to minimize wind and water erosion and to preserve their structural...

Artificial neural network approach for mapping contrasting tillage practices

USDA-ARS?s Scientific Manuscript database

Tillage information is crucial for environmental modeling as it directly affects evapotranspiration, infiltration, runoff, carbon sequestration, and soil losses due to wind and water erosion from agricultural fields. However, collecting this information can be time consuming and costly. Remote sensi...

Wind sorting affects differently the organo-mineral composition of saltating and particulate materials in contrasting texture agricultural soils

NASA Astrophysics Data System (ADS)

Iturri, Laura Antonela; Funk, Roger; Leue, Martin; Sommer, Michael; Buschiazzo, Daniel Eduardo

2017-10-01

There is little information about the mineral and organic composition of sediments eroded by wind at different heights. Because of that, wind tunnel simulations were performed on four agricultural loess soils of different granulometry and their saltating materials collected at different heights. The particulate matter with an aerodynamic diameter mainly smaller than 10 μm (PM10) of these soils was obtained separately by a laboratory method. Results indicated that the granulometric composition of sediments collected at different heights was more homogeneous in fine- than in sandy-textured soils, which were more affected by sorting effects during wind erosion. This agrees with the preferential transport of quartz at low heights and of clay minerals at greater heights. SOC contents increased with height, but the composition of the organic materials was different: stable carboxylic acids, aldehydes, amides and aromatics were preferentially transported close to the ground because their were found in larger aggregates, while plant debris and polysaccharides, carbohydrates and derivatives of microbial origin from organic matter dominated at greater heights for all soil types. The amount of SOC in the PM10 fraction was higher when it was emitted from sandy than from fine textured soils. Because of the sorting process produced by wind erosion, the stable organic matter compounds will be transported at low heights and local scales, modifying soil fertility due to nutrient exportation, while less stable organic compounds will be part of the suspension losses, which are known to affect some processes at regional- or global scale.

Large-scale variability of wind erosion mass flux rates at Owens Lake 1. Vertical profiles of horizontal mass fluxes of wind-eroded particles with diameter greater than 50 μm

USGS Publications Warehouse

Gillette, Dale A.; Fryrear, D.W.; Xiao, Jing Bing; Stockton, Paul; Ono, Duane; Helm, Paula J.; Gill, Thomas E; Ley, Trevor

1997-01-01

A field experiment at Owens (dry) Lake, California, tested whether and how the relative profiles of airborne horizontal mass fluxes for >50-μm wind-eroded particles changed with friction velocity. The horizontal mass flux at almost all measured heights increased proportionally to the cube of friction velocity above an apparent threshold friction velocity for all sediment tested and increased with height except at one coarse-sand site where the relative horizontal mass flux profile did not change with friction velocity. Size distributions for long-time-averaged horizontal mass flux samples showed a saltation layer from the surface to a height between 30 and 50 cm, above which suspended particles dominate. Measurements from a large dust source area on a line parallel to the wind showed that even though the saltation flux reached equilibrium ∼650 m downwind of the starting point of erosion, weakly suspended particles were still input into the atmosphere 1567 m downwind of the starting point; thus the saltating fraction of the total mass flux decreased after 650 m. The scale length difference and ratio of 70/30 suspended mass flux to saltation mass flux at the farthest down wind sampling site confirm that suspended particles are very important for mass budgets in large source areas and that saltation mass flux can be a variable fraction of total horizontal mass flux for soils with a substantial fraction of <100-μm particles.

Coastal Erosion in a Coral Reef Island, Taiping Island, South China Sea

NASA Astrophysics Data System (ADS)

Su, S.; Ma, G.; Liang, M.; Chu, J.

2011-12-01

Reef flats surrounding islands are known to dissipate much offshore wave energy, and thereby protect beaches from erosion. Taiping Island, the largest coral reef islands of the Spratly Islands in the South China Sea, has been observed the shorelines erosion on the southwest coast over past decades. It is recognized that wave and current processes across coral reefs affect reef-island development and morphology. A number of studies suggest effects of climate changes, sea-level rise and storm-intensity increase, determine the magnitude of wave energy on the reef platform and will likely intensify the erosion. The topographical change in the local region, the southwest reef flat was dredged a channel for navigation, may be a significant factor in influencing current characteristics. Numerical modeling is used to describe both hydrodynamics and sediment dynamics because there are no field measurements available around the reef flat. Field observations off the island conducted in August 2004 and November 2005 provides offshore wave characteristics of the predominant wind seasons. Numerical simulations perform the spatial and temporal variation of waves and current patterns and coastal erosion potential on the reef platform.

Residue decomposition of submodel of WEPS

USDA-ARS?s Scientific Manuscript database

The Residue Decomposition submodel of the Wind Erosion Prediction System (WEPS) simulates the decrease in crop residue biomass due to microbial activity. The decomposition process is modeled as a first-order reaction with temperature and moisture as driving variables. Decomposition is a function of ...

30 CFR 762.5 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... investments that have been made on the basis of a long-term coal contract in power plants, railroads, coal... threatened species of animals or plants, uncommon geologic formations, paleontological sites, National... dunes, severe wind or soil erosion, frequent flooding, avalanches and areas of unstable geology...

Geologic effects of hurricanes

NASA Astrophysics Data System (ADS)

Coch, Nicholas K.

1994-08-01

Hurricanes are intense low pressure systems of tropical origin. Hurricane damage results from storm surge, wind, and inland flooding from heavy rainfall. Field observations and remote sensing of recent major hurricanes such as Hugo (1989), Andrew (1992) and Iniki (1992) are providing new insights into the mechanisms producing damage in these major storms. Velocities associated with hurricanes include the counterclockwise vortex winds flowing around the eye and the much slower regional winds that steer hurricane and move it forward. Vectorial addition of theseof these two winds on the higher effective wind speed than on the left side. Coast-parallel hurricane tracks keep the weaker left side of the storm against the coast, whereas coast-normal tracks produce a wide swath of destruction as the more powerful right side of the storm cuts a swath of destruction hundreds of kilometers inland. Storm surge is a function of the wind speed, central pressure, shelf slope, shoreline configuration, and anthropogenic alterations to the shoreline. Maximum surge heights are not under the eye of the hurricane, where the pressure is lowest, but on the right side of the eye at the radius of maximum winds, where the winds are strongest. Flood surge occurs as the hurricane approaches land and drives coastal waters, and superimposed waves, across the shore. Ebb surge occurs when impounded surface water flows seaward as the storm moves inland. Flood and ebb surge damage have been greatly increased in recent hurricanes as a result of anthropogenic changes along the shoreline. Hurricane wind damage occurs on three scales — megascale, mesoscale and microscale. Local wind damage is a function of wind speed, exposure and structural resistance to velocity pressure, wind drag and flying debris. Localized extreme damage is caused by gusts that can locally exceed sustained winds by a factor of two in areas where there is strong convective activity. Geologic changes occuring in hurricanes include beach erosion, dune erosion, inlet formation from flood and ebb surge, landscape changes through tree destruction by wind and nearshore channeling and sedimentation resulting from ebb surge. Multi-decadal wet and dry cycles in West Africa seem to be associated with increases (wet periods) and decreases (dry periods) in the frequency of Atlantic Coast landfalling hurricanes. Coastalzone population and development has increased markedly in a time of low hurricane frequency in the 24 year dry cycle from1970 to the present. However, no previous climatic cycle in this century has exceeded 26 years. We may entering a multi-decadal cycle of greater hurricane activity, placing these highly urbanized shorelines in considerable danger.

Three mars years: Viking lander 1 imaging observations

USGS Publications Warehouse

Arvidson, R. E.; Guinness, E.A.; Moore, H.J.; Tillman, J.; Wall, S.D.

1983-01-01

The Mutch Memorial Station (Viking Lander 1) on Mars acquired imaging and meteorological data over a period of 2245 martian days (3:3 martian years). This article discusses the deposition and erosion of thin deposits (ten to hundreds of micrometers) of bright red dust associated with global dust storms, and the removal of centimeter amounts of material in selected areas during a dust storm late in the third winter. Atmospheric pressure data acquired during the period of intense erosion imply that baroclinic disturbances and strong diurnal solar tidal heating combined to produce strong winds. Erosion occurred principally in areas where soil cohesion was reduced by earlier surface sampler activities. Except for redistribution of thin layers of materials, the surface appears to be remarkably stable, perhaps because of cohesion of the undisturbed surface material.

Three Mars years: viking lander 1 imaging observations.

PubMed

Arvidson, R E; Guinness, E A; Moore, H J; Tillman, J; Wall, S D

1983-11-04

The Mutch Memorial Station (Viking Lander 1) on Mars acquired imaging and meteorological data over a period of 2245 martian days (3:3 martian years). This article discusses the deposition and erosion of thin deposits (ten to hundreds of micrometers) of bright red dust associated with global dust storms, and the removal of centimeter amounts of material in selected areas during a dust storm late in the third winter. Atmospheric pressure data acquired during the period of intense erosion imply that baroclinic disturbances and strong diurnal solar tidal heating combined to produce strong winds. Erosion occurred principally in areas where soil cohesion was reduced by earlier surface sampler activities. Except for redistribution of thin layers of materials, the surface appears to be remarkably stable, perhaps because of cohesion of the undisturbed surface material.

Three Mars years - Viking Lander 1 imaging observations

NASA Technical Reports Server (NTRS)

Arvidson, R. E.; Guinness, E. A.; Moore, H. J.; Tillman, J.; Wall, S. D.

1983-01-01

The Mutch Memorial Station (Viking Lander 1) on Mars acquired imaging and meteorological data over a period of 2245 martian days (3.3 martian years). This article discusses the deposition and erosion of thin deposits (ten to hundreds of micrometers) of bright red dust associated with global dust storms, and the removal of centimeter amounts of material in selected areas during a dust storm late in the third winter. Atmospheric pressure data acquired during the period of intense erosion imply that baroclinic disturbances and strong diurnal solar tidal heating combined to produce strong winds. Erosion occurred principally in areas where soil cohesion was reduced by earlier surface sampler activities. Except for redistribution of thin layers of materials, the surface appears to be remarkably stable, perhaps because of cohension of the undisturbed surface material.

Soil organic carbon dust emission: an omitted global source of atmospheric CO2.

PubMed

Chappell, Adrian; Webb, Nicholas P; Butler, Harry J; Strong, Craig L; McTainsh, Grant H; Leys, John F; Viscarra Rossel, Raphael A

2013-10-01

Soil erosion redistributes soil organic carbon (SOC) within terrestrial ecosystems, to the atmosphere and oceans. Dust export is an essential component of the carbon (C) and carbon dioxide (CO(2)) budget because wind erosion contributes to the C cycle by removing selectively SOC from vast areas and transporting C dust quickly offshore; augmenting the net loss of C from terrestrial systems. However, the contribution of wind erosion to rates of C release and sequestration is poorly understood. Here, we describe how SOC dust emission is omitted from national C accounting, is an underestimated source of CO(2) and may accelerate SOC decomposition. Similarly, long dust residence times in the unshielded atmospheric environment may considerably increase CO(2) emission. We developed a first approximation to SOC enrichment for a well-established dust emission model and quantified SOC dust emission for Australia (5.83 Tg CO(2)-e yr(-1)) and Australian agricultural soils (0.4 Tg CO(2)-e yr(-1)). These amount to underestimates for CO(2) emissions of ≈10% from combined C pools in Australia (year = 2000), ≈5% from Australian Rangelands and ≈3% of Australian Agricultural Soils by Kyoto Accounting. Northern hemisphere countries with greater dust emission than Australia are also likely to have much larger SOC dust emission. Therefore, omission of SOC dust emission likely represents a considerable underestimate from those nations' C accounts. We suggest that the omission of SOC dust emission from C cycling and C accounting is a significant global source of uncertainty. Tracing the fate of wind-eroded SOC in the dust cycle is therefore essential to quantify the release of CO(2) from SOC dust to the atmosphere and the contribution of SOC deposition to downwind C sinks. © 2013 John Wiley & Sons Ltd.

Wind erosion risk in the southwest of Buenos Aires Province, Argentina, and its relationship to the productivity index

NASA Astrophysics Data System (ADS)

Silenzi, Juan C.; Echeverría, Nora E.; Vallejos, Adrián G.; Bouza, Mariana E.; De Lucia, Martín P.

2012-01-01

Wind erosion risk (WER) for soils of each municipality in the southwest (SW) of Buenos Aires Province (10,491,172 ha) was determined using the wind erosion equation (WEQ) model. WER results from multiplying the soil erodibility index (" I") of the soil by the climatic factor ( C). WER (Mg ha -1 year -1) of each municipality was: Bahía Blanca: 22.4, Coronel Dorrego: 18.6, Coronel Pringles: 4.5, Coronel Rosales: 48.2, Coronel Suárez: 4.5, Guaminí: 3.0, Patagones: 104.6, Puan: 12.2, Saavedra: 3.0, Tornquist: 6.8, and Villarino: 31.7. The maximum weighted average of " I" (Mg ha -1 year -1) corresponded to Coronel Rosales (87.6), Patagones (87.2), Villarino (85.7), Puan (67.9); Guaminí (59.6), Coronel Dorrego (53.1), and Bahía Blanca (39.3); the remaining municipalities ranged between 34.9 and 32.1 Mg ha -1 year -1. The highest C (%) corresponded to Patagones (120), Bahía Blanca (57), Coronel Rosales (55), Villarino (37), Coronel Dorrego (35), Tornquist (21), and Puan (18); for the remaining municipalities it was 14%. The productivity index (PI) is known to establish a numerical value of the productive capacity of lands. The relationship between WER and PI, weighted averages, in all the studied municipalities was fitted by means of a linear model, WER (Mg ha -1 year -1) = 95.23 - 2.09 * PI (%) ( R2 = 66%), and a second-order polynomial model, WER (Mg ha -1 year -1) = 139.41 - 5.86 * PI (%) + 0.07 * PI 2 (%) ( R2 = 74%). No statistically significant relationship was found between WER and PI for each municipality.

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.

Influence of sea ice on Arctic coasts

NASA Astrophysics Data System (ADS)

Barnhart, K. R.; Kay, J. E.; Overeem, I.; Anderson, R. S.

2017-12-01

Coasts form the dynamic interface between the terrestrial and oceanic systems. In the Arctic, and in much of the world, the coast is a focal point for population, infrastructure, biodiversity, and ecosystem services. A key difference between Arctic and temperate coasts is the presence of sea ice. Changes in sea ice cover can influence the coast because (1) the length of the sea ice-free season controls the time over which nearshore water can interact with the land, and (2) the location of the sea ice edge controls the fetch over which storm winds can interact with open ocean water, which in turn governs nearshore water level and wave field. We first focus on the interaction of sea ice and ice-rich coasts. We combine satellite records of sea ice with a model for wind-driven storm surge and waves to estimate how changes in the sea ice-free season have impacted the nearshore hydrodynamic environment along Alaska's Beaufort Sea Coast for the period 1979-2012. This region has experienced some of the greatest changes in both sea ice cover and coastal erosion rates in the Arctic: the median length of the open-water season has expanded by 90 percent, while coastal erosion rates have more than doubled from 8.7 to 19 m yr-1. At Drew Point, NW winds increase shoreline water levels that control the incision of a submarine notch, the rate-limiting step of coastal retreat. The maximum water-level setup at Drew Point has increased consistently with increasing fetch. We extend our analysis to the entire Arctic using both satellite-based observations and global coupled climate model output from the Community Earth System Model Large Ensemble (CESM-LE) project. This 30-member ensemble employs a 1-degree version of the CESM-CAM5 historical forcing for the period 1920-2005, and RCP 8.5 forcing from 2005-2100. A control model run with constant pre-industrial (1850) forcing characterizes internal variability in a constant climate. Finally, we compare observations and model results to identify locations of both observed and expected rapid sea ice change. Based on satellite observations, the median length of the 2012 open-water season expanded by between 1.5 and 3-fold relative to 1979 over the Arctic Sea region. This results in open water during the stormy Arctic fall, with implications for not only coastal processes but for amplification of warming on land.

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...

[Spatio-temporal change of sand-fixing function and its driving forces in desertification control ecological function area of Hunshandake, China].

PubMed

Shen, Lu; Tian, Mei-rong; Gao, Ji-xi; Qian, Jin-ping

2016-01-01

Soil erosion is an important ecological and environmental problem in Hunshandake Desert, and the sand-fixing function determines the degree of ecological security in the entire region. In order to clarify the situation of windbreak and sand fixation in Hunshandake area, and to guide the prevention and treatment of desertification on regional scale, based on the meteorological and remote sensing data, this paper quantitatively analyzed the temporal and spatial pattern of windbreak and sand fixation ability between 2000-2010 by the revised wind erosion equation (RWEQ) model, meanwhile, the driving forces for each county ( or banner) in the functional zone were analyzed with the method of principal component analysis. The results showed that there was a fluctuation of the sand fixing capacity in Hunshandake over time, generally rendering a decline trend. The coniferous forest and grassland had strong windbreak and sand fixation capacity in unit area among the various land categories. In terms of spatial distribution, the windbreak and sand fixation function in western and southeastern region was weak and needed to be strengthened with ecological restoration efforts. Through the study of the social driving forces of each administrative region in the function zone, there were 3 main social driving forces of soil erosion in the administrative functions: the intensity of input-output, the level of economic development and the level of agriculture-husbandry development.

Can biosolids reduce wind erosion of agricultural soils?

USDA-ARS?s Scientific Manuscript database

The application of biosolids to agricultural land has the potential to improve soil health and crop production. In addition, organic material contained in biosolids may enhance biological activity, retention of soil water, and soil aggregation. Thus, there is a likelihood that biosolids applied to s...

Roughness configuration matters for aeolian sediment flux

USDA-ARS?s Scientific Manuscript database

The parameterisation of surface roughness effects on aeolian sediment transport is a key source of uncertainty in wind erosion models. Roughness effects are typically represented by bulk drag-partitioning schemes that scale the threshold friction velocity (u*t) for soil entrainment by the ratio of s...

Quantifying Anthropogenic Dust Emissions

NASA Astrophysics Data System (ADS)

Webb, Nicholas P.; Pierre, Caroline

2018-02-01

Anthropogenic land use and land cover change, including local environmental disturbances, moderate rates of wind-driven soil erosion and dust emission. These human-dust cycle interactions impact ecosystems and agricultural production, air quality, human health, biogeochemical cycles, and climate. While the impacts of land use activities and land management on aeolian processes can be profound, the interactions are often complex and assessments of anthropogenic dust loads at all scales remain highly uncertain. Here, we critically review the drivers of anthropogenic dust emission and current evaluation approaches. We then identify and describe opportunities to: (1) develop new conceptual frameworks and interdisciplinary approaches that draw on ecological state-and-transition models to improve the accuracy and relevance of assessments of anthropogenic dust emissions; (2) improve model fidelity and capacity for change detection to quantify anthropogenic impacts on aeolian processes; and (3) enhance field research and monitoring networks to support dust model applications to evaluate the impacts of disturbance processes on local to global-scale wind erosion and dust emissions.

All Along the Fractures

NASA Image and Video Library

2015-09-30

This image from NASA Mars Reconnaissance Orbiter spacecraft provides information about erosion and movement of surface material, about wind and weather patterns, even about the soil grains and grain sizes. However, looking past the dunes, these images also reveal the nature of the substrate beneath. Within the spaces between the dunes, a resistant and highly fractured surface is revealed. The fractured ground is resistant to erosion by the wind, and suggests the material is bedrock that is now shattered by a history of bending stresses or temperature changes, such as cooling, for example. Alternately, the surface may be a sedimentary layer that was once wet and shrunk and fractured as it dried, like gigantic mud cracks. In either case, the relative small and indistinct fractures have trapped the dark dune sand marching overhead. Now the fractures have become quite distinct, allowing us to examine the orientation and spacing of the fractures to learn more about the processes that formed them. http://photojournal.jpl.nasa.gov/catalog/PIA19958

I Got Them Dust Bowl Blues: Wind Erosion in the Music of the Southern Great Plains

NASA Astrophysics Data System (ADS)

Lee, J. A.

2017-12-01

This paper deals with the role of wind erosion and blowing dust on the music of the Dust Bowl region, a portion of the southern Great Plains of the United States. A defining characteristic of the region is dust storms, and in the 1930s, severe dust storms created dramatic images that came to symbolize all of the economic, social and environmental hardships suffered by the people during the 1930s. The music of the time, by Woody Guthrie and others, suggested that the region was being destroyed, never to recover. The region was resilient, however, and in recent decades, dust has been depicted in songs either as an adversity to be endured or simply as a normal part of life in the area. It may be that blowing dust has become a defining characteristic of the region because of a somewhat warped sense of pride in living in an often-difficult environment.

History of Martian Surface Changes Observed by Mars Global Surveyor

NASA Astrophysics Data System (ADS)

Geissler, P. E.; Enga, M.; Mukherjee, P.

2009-12-01

The changing appearance of Mars has fascinated observers for centuries, yet much is still unknown about the winds and sediments that alter the albedo of vast areas of the planet’s surface. A variety of aeolian processes contribute to the deposition and erosion of dust on Mars, with distinct causes and timescales that vary with season and location. Over decadal timescales, these processes act to alter the planetary albedo distribution enough to significantly impact the climate and global circulation of winds on Mars (Geissler, JGR 110, E02001, 2005; Fenton et al., Nature 446, 646, 2007). We are documenting the extent and frequency of Martian surface changes by analyzing the rich record of observations made by the Mars Global Surveyor mission. We are currently completing a time-series of global mosaics produced from wide angle MOC images showing in detail how the planet’s surface changed in appearance between early 1999 and late 2006, a period of 4 Martian years. The MOC mosaics reveal a surprising range of temporal behavior among variable features in different regions of Mars. Episodic dust deposition followed by episodic clearing can be seen in Syrtis Major. Gradual erosion by persistent seasonal winds can be seen in many equatorial areas such as southern Alcyonius. Gradual erosion by dust-devils is prevalent at higher latitudes and notably in Nilosyrtis, where the albedo boundary dividing the high albedo tropics from the dark terrain to the north is slowly advancing southwards onto brighter terrain. Solis Planum, a high plateau south of the Valles Marineris, changes on a nearly continuous basis. Many of the moving albedo boundaries (such as those at Oxia Palus and the Southern tropical dark band) display high albedo margins that may be aprons of dust swept away by the advancing erosion. The data also show clear evidence for dust deposition onto already dust-covered regions, a phenomenon that was suspected but not demonstrated by Geissler (2005). The final MOC images show significant brightening in Vastitas Borealis, continuing a trend that may have begun in the 1980s.

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…

A linear relationship between wave power and erosion determines salt-marsh resilience to violent storms and hurricanes

PubMed Central

Leonardi, Nicoletta; Ganju, Neil K.; Fagherazzi, Sergio

2016-01-01

Salt marsh losses have been documented worldwide because of land use change, wave erosion, and sea-level rise. It is still unclear how resistant salt marshes are to extreme storms and whether they can survive multiple events without collapsing. Based on a large dataset of salt marsh lateral erosion rates collected around the world, here, we determine the general response of salt marsh boundaries to wave action under normal and extreme weather conditions. As wave energy increases, salt marsh response to wind waves remains linear, and there is not a critical threshold in wave energy above which salt marsh erosion drastically accelerates. We apply our general formulation for salt marsh erosion to historical wave climates at eight salt marsh locations affected by hurricanes in the United States. Based on the analysis of two decades of data, we find that violent storms and hurricanes contribute less than 1% to long-term salt marsh erosion rates. In contrast, moderate storms with a return period of 2.5 mo are those causing the most salt marsh deterioration. Therefore, salt marshes seem more susceptible to variations in mean wave energy rather than changes in the extremes. The intrinsic resistance of salt marshes to violent storms and their predictable erosion rates during moderate events should be taken into account by coastal managers in restoration projects and risk management plans. PMID:26699461

A linear relationship between wave power and erosion determines salt-marsh resilience to violent storms and hurricanes

USGS Publications Warehouse

Leonardi, Nicoletta; Ganju, Neil K.; Fagherazzi, Sergio

2016-01-01

Salt marsh losses have been documented worldwide because of land use change, wave erosion, and sea-level rise. It is still unclear how resistant salt marshes are to extreme storms and whether they can survive multiple events without collapsing. Based on a large dataset of salt marsh lateral erosion rates collected around the world, here, we determine the general response of salt marsh boundaries to wave action under normal and extreme weather conditions. As wave energy increases, salt marsh response to wind waves remains linear, and there is not a critical threshold in wave energy above which salt marsh erosion drastically accelerates. We apply our general formulation for salt marsh erosion to historical wave climates at eight salt marsh locations affected by hurricanes in the United States. Based on the analysis of two decades of data, we find that violent storms and hurricanes contribute less than 1% to long-term salt marsh erosion rates. In contrast, moderate storms with a return period of 2.5 mo are those causing the most salt marsh deterioration. Therefore, salt marshes seem more susceptible to variations in mean wave energy rather than changes in the extremes. The intrinsic resistance of salt marshes to violent storms and their predictable erosion rates during moderate events should be taken into account by coastal managers in restoration projects and risk management plans.

A linear relationship between wave power and erosion determines salt-marsh resilience to violent storms and hurricanes.

PubMed

Leonardi, Nicoletta; Ganju, Neil K; Fagherazzi, Sergio

2016-01-05

Salt marsh losses have been documented worldwide because of land use change, wave erosion, and sea-level rise. It is still unclear how resistant salt marshes are to extreme storms and whether they can survive multiple events without collapsing. Based on a large dataset of salt marsh lateral erosion rates collected around the world, here, we determine the general response of salt marsh boundaries to wave action under normal and extreme weather conditions. As wave energy increases, salt marsh response to wind waves remains linear, and there is not a critical threshold in wave energy above which salt marsh erosion drastically accelerates. We apply our general formulation for salt marsh erosion to historical wave climates at eight salt marsh locations affected by hurricanes in the United States. Based on the analysis of two decades of data, we find that violent storms and hurricanes contribute less than 1% to long-term salt marsh erosion rates. In contrast, moderate storms with a return period of 2.5 mo are those causing the most salt marsh deterioration. Therefore, salt marshes seem more susceptible to variations in mean wave energy rather than changes in the extremes. The intrinsic resistance of salt marshes to violent storms and their predictable erosion rates during moderate events should be taken into account by coastal managers in restoration projects and risk management plans.

Process-based coastal erosion modeling for Drew Point (North Slope, Alaska)

USGS Publications Warehouse

Ravens, Thomas M.; Jones, Benjamin M.; Zhang, Jinlin; Arp, Christopher D.; Schmutz, Joel A.

2012-01-01

A predictive, coastal erosion/shoreline change model has been developed for a small coastal segment near Drew Point, Beaufort Sea, Alaska. This coastal setting has experienced a dramatic increase in erosion since the early 2000’s. The bluffs at this site are 3-4 m tall and consist of ice-wedge bounded blocks of fine-grained sediments cemented by ice-rich permafrost and capped with a thin organic layer. The bluffs are typically fronted by a narrow (∼ 5  m wide) beach or none at all. During a storm surge, the sea contacts the base of the bluff and a niche is formed through thermal and mechanical erosion. The niche grows both vertically and laterally and eventually undermines the bluff, leading to block failure or collapse. The fallen block is then eroded both thermally and mechanically by waves and currents, which must occur before a new niche forming episode may begin. The erosion model explicitly accounts for and integrates a number of these processes including: (1) storm surge generation resulting from wind and atmospheric forcing, (2) erosional niche growth resulting from wave-induced turbulent heat transfer and sediment transport (using the Kobayashi niche erosion model), and (3) thermal and mechanical erosion of the fallen block. The model was calibrated with historic shoreline change data for one time period (1979-2002), and validated with a later time period (2002-2007).

Investigating Mars: Candor Chasma

NASA Image and Video Library

2018-01-12

This image shows part of eastern Candor Chasma. In the middle of the image is a set of linear ridges and valleys. These features are called yardangs and are created by uniform winds that winnow away materials. Once the valleys are formed the wind then is funneled through the valley and erosion continues more in the valley than on the ridges. At the bottom of the valleys there are sand materials covering the slope between the valleys and the surrounding chasma floor. Beyond this coating of sand there are darker sand deposits where wind has accumulated the sand into larger dunes. The brighter mesa on the right side of the image has also been wind eroded into yardangs, but are aligned in a different direction than the larger yardangs. This indicates that wind directions within the canyon have changed over time. Candor Chasma is one of the largest canyons that make up Valles Marineris. It is approximately 810 km long (503 miles) and has is divided into two regions - eastern and western Candor. Candor is located south of Ophir Chasma and north of Melas Chasma. The border with Melas Chasma contains many large landslide deposits. The floor of Candor Chasma includes a variety of landforms, including layered deposits, dunes, landslide deposits and steep sided cliffs and mesas. Many forms of erosion have shaped Chandor Chasma. There is evidence of wind and water erosion, as well as significant gravity driven mass wasting (landslides). The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 10551 Latitude: -6.93639 Longitude: 288.562 Instrument: VIS Captured: 2004-05-01 02:24 https://photojournal.jpl.nasa.gov/catalog/PIA22165

Wind Carved Rock

NASA Image and Video Library

2016-10-19

The distinctively fluted surface and elongated hills in this image in Medusae Fossae are caused by wind erosion of a soft fine-grained rock. Called yardangs, these features are aligned with the prevailing wind direction. This wind direction would have dominated for a very long time to carve these large-scale features into the exposed rock we see today. Yardangs not only reveal the strength and direction of historic winds, but also reveal something of the host rock itself. Close inspection by HiRISE shows an absence of boulders or rubble, especially along steep yardang cliffs and buttresses. The absence of rubble and the scale of the yardangs tells us that the host rock consists only of weakly cemented fine granules in tens of meters or more thick deposits. Such deposits could have come from extended settling of volcanic ash, atmospheric dust, or accumulations of wind deposited fine sands. After a time these deposits became cemented and cohesive, illustrated by the high standing relief and exposed cliffs. http://photojournal.jpl.nasa.gov/catalog/PIA21111

Threshold for sand mobility on Mars calibrated from seasonal variations of sand flux.

PubMed

Ayoub, F; Avouac, J-P; Newman, C E; Richardson, M I; Lucas, A; Leprince, S; Bridges, N T

2014-09-30

Coupling between surface winds and saltation is a fundamental factor governing geological activity and climate on Mars. Saltation of sand is crucial for both erosion of the surface and dust lifting into the atmosphere. Wind tunnel experiments along with measurements from surface meteorology stations and modelling of wind speeds suggest that winds should only rarely move sand on Mars. However, evidence for currently active dune migration has recently accumulated. Crucially, the frequency of sand-moving events and the implied threshold wind stresses for saltation have remained unknown. Here we present detailed measurements of Nili Patera dune field based on High Resolution Imaging Science Experiment images, demonstrating that sand motion occurs daily throughout much of the year and that the resulting sand flux is strongly seasonal. Analysis of the seasonal sand flux variation suggests an effective threshold for sand motion for application to large-scale model wind fields (1-100 km scale) of τ(s)=0.01±0.0015 N m(-2).

Geometeorological data collected by the USGS Desert Winds Project at Gold Spring, Great Basin desert, northeastern Arizona, 1979-1992

USGS Publications Warehouse

Helm, P.J.; Breed, C.S.; Tigges, R.K.; Garcia, P.A.

1995-01-01

The primary purpose of the Desert Winds Project (DWP) is to obtain high-resolution meteorological data and related surface geological and vegetation data for natural (e.g., uncultivated) desert sites where wind is or has been a major erosive or depositional force. The objectives are twofold: (1) to provide the detailed field measurements needed to carry out quantitative studies of wind as an agent of surface geologic change; and (2) to establish a baseline for defining the 'normal' range of climatic conditions that can be expected to occur on a decadal time scale, in areas considered representative of the major American deserts. The Gold Spring locality was selected to represent that part of the Great Basin Desert that extends into northeastern Arizona. The long-term goal for acquiring and analyzing the Desert Winds Project data is to use them to address problems of land resource degradation by wind, whether resulting from climatic variation aridification) or human activities (desertification), or both (see techinfo.doc).

Changes on the coastline of buenaventura bay (colombian pacific) and its relationship with the climatic conditions

NASA Astrophysics Data System (ADS)

Coca-Domínguez, Oswaldo; Ricaurte-Villota, Constanza; Andres Ordoñez, Silvio

2016-04-01

Some authors point out that the variability of a coastal system is the response of physical factors (climate, waves, currents, wind, etc.) or combination of some of them, for example long-term variations in the relationship between climate and supply of sedimentary material. For Colombian Pacific coast it has been said that the regimen of meso-tidal is one of the agents that contribute to changes in the morphology of the littoral zone. Between 2012-2015 was conducted a research in the mouth of Buenaventura Bay (Colombia Pacific coast), using two stations: Soldado point (southern point of the bay) and Bazan point (the northern point of the bay), for those stations the digital elevation model (DEM) was performed using a DGPS with technology GNSS the recent evolution of the coastline and changes in volume of sand from beaches for two scalar approaches were determined: annual and intra-annual. The use of ArcGIS 3D Analyst in the DEMs allowed to calculate the cubic area between the raised surfaces each month. Changes in the coastline were made using Digital Shoreline Analysis System (DSAS) an ARCGIS extension. We used zonal and meridional components of the wind data near the coast from WindSat, rainfall and sea level anomaly data from the database AVISO (Archiving, Validation and Interpretation of Satellite Oceanographic), and sea level pressure (SLP) from NCEP/NCAR (National Center for Environmental Prediction/ National Center for Atmospheric Research), in collaboration with the National Oceanic and Atmospheric Administration (NOAA). Finally, climatic variables were correlated with the rates of coastal erosion and changes in sand volume of the beaches, because wind and precipitation are some of the factors in sediment transport. The study showed erosion rates with negative values in 2014 and 2015 that represent loss of land, the intra-annual variability in September and October were the highest loss of land, this coincides with the values of the highest tides of the year. The results suggest that in the last 5 years have risen tides (about 50 cm in spring tide), accompanied by strong winds, which has caused lost land in some areas because overwash and of flooding processes. KEY WORDS: Coastal erosion, coastal processes, climate, tides

Sediment and erosion control laboratory facility expansion.

DOT National Transportation Integrated Search

2016-08-01

The Sediment and Erosion Control Laboratory (SEC Lab), formerly the Hydraulics, Sedimentation, and : Erosion Control Laboratory, is operated by the Texas A&M Transportation Institutes Environment and : Planning Program. Performance evaluation prog...

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.

Erosion potential of the Yangtze Delta under sediment starvation and climate change.

PubMed

Yang, H F; Yang, S L; Xu, K H; Wu, H; Shi, B W; Zhu, Q; Zhang, W X; Yang, Z

2017-09-05

Deltas are widely threatened by sediment starvation and climate change. Erosion potential is an important indicator of delta vulnerability. Here, we investigate the erosion potential of the Yangtze Delta. We found that over the past half century the Yangtze's sediment discharge has decreased by 80% due to the construction of >50,000 dams and soil conservation, whereas the wind speed and wave height in the delta region have increased by 5-7%, and the sea level has risen at a rate of 3 mm/yr. According to hydrodynamic measurements and analyses of seabed sediments, the period when bed shear stress due to combined current-wave action under normal weather conditions exceeds the critical bed shear stress for erosion (τ cr ) accounts for 63% of the total observed period on average and can reach 100% during peak storms. This explains why net erosion has occurred in some areas of the subaqueous delta. We also found that the increase with depth of τ cr is very gradual in the uppermost several metres of the depositional sequence. We therefore expect that the Yangtze subaqueous delta will experience continuous erosion under sediment starvation and climate change in the next decades of this century or even a few centuries.

Hurricane impacts on coastal wetlands: A half-century record of storm-generated features from Southern Louisiana

USGS Publications Warehouse

Morton, R.A.; Barras, J.A.

2011-01-01

Temporally and spatially repeated patterns of wetland erosion, deformation, and deposition are observed on remotely sensed images and in the field after hurricanes cross the coast of Louisiana. The diagnostic morphological wetland features are products of the coupling of high-velocity wind and storm-surge water and their interaction with the underlying, variably resistant, wetland vegetation and soils. Erosional signatures include construction of orthogonal-elongate ponds and amorphous ponds, pond expansion, plucked marsh, marsh denudation, and shoreline erosion. Post-storm gravity reflux of floodwater draining from the wetlands forms dendritic incisions around the pond margins and locally integrates drainage pathways forming braided channels. Depositional signatures include emplacement of broad zones of organic wrack on topographic highs and inorganic deposits of variable thicknesses and lateral extents in the form of shore-parallel sandy washover terraces and interior-marsh mud blankets. Deformational signatures primarily involve laterally compressed marsh and displaced marsh mats and balls. Prolonged water impoundment and marsh salinization also are common impacts associated with wetland flooding by extreme storms. Many of the wetland features become legacies that record prior storm impacts and locally influence subsequent storm-induced morphological changes. Wetland losses caused by hurricane impacts depend directly on impact duration, which is controlled by the diameter of hurricane-force winds, forward speed of the storm, and wetland distance over which the storm passes. Distinguishing between wetland losses caused by storm impacts and losses associated with long-term delta-plain processes is critical for accurate modeling and prediction of future conversion of land to open water. ?? Coastal Education & Research Foundation 2011.

Hurricane impacts on coastal wetlands: a half-century record of storm-generated features from southern Louisiana

USGS Publications Warehouse

Morton, Robert A.; Barras, John A.

2011-01-01

Temporally and spatially repeated patterns of wetland erosion, deformation, and deposition are observed on remotely sensed images and in the field after hurricanes cross the coast of Louisiana. The diagnostic morphological wetland features are products of the coupling of high-velocity wind and storm-surge water and their interaction with the underlying, variably resistant, wetland vegetation and soils. Erosional signatures include construction of orthogonal-elongate ponds and amorphous ponds, pond expansion, plucked marsh, marsh denudation, and shoreline erosion. Post-storm gravity reflux of floodwater draining from the wetlands forms dendritic incisions around the pond margins and locally integrates drainage pathways forming braided channels. Depositional signatures include emplacement of broad zones of organic wrack on topographic highs and inorganic deposits of variable thicknesses and lateral extents in the form of shore-parallel sandy washover terraces and interior-marsh mud blankets. Deformational signatures primarily involve laterally compressed marsh and displaced marsh mats and balls. Prolonged water impoundment and marsh salinization also are common impacts associated with wetland flooding by extreme storms. Many of the wetland features become legacies that record prior storm impacts and locally influence subsequent storm-induced morphological changes. Wetland losses caused by hurricane impacts depend directly on impact duration, which is controlled by the diameter of hurricane-force winds, forward speed of the storm, and wetland distance over which the storm passes. Distinguishing between wetland losses caused by storm impacts and losses associated with long-term delta-plain processes is critical for accurate modeling and prediction of future conversion of land to open water.

Balancing energy, conservation, and soil health requirements for plant biomass

USDA-ARS?s Scientific Manuscript database

The importance of crop residue for mitigating water and wind erosion, sustaining soil organic carbon (SOC) levels, and providing animal feed and bedding is well recognized around the world. But, those critical needs are no longer the only factors influencing crop residue management decisions. Global...

Active old-field restoration in the most arid lands of the Great Basin

USDA-ARS?s Scientific Manuscript database

Restoration of former agricultural fields can be challenging, especially in arid systems, where factors such as wind erosion, water stress, soil alteration, and competition from weeds can strongly affect plant establishment and growth. Experiments were conducted in two former agricultural fields in ...

30 CFR 816.22 - Topsoil and subsoil.

Code of Federal Regulations, 2011 CFR

2011-07-01

... site of small structures, such as power poles, signs, or fence lines; or (ii) Will not destroy the... unnecessary compaction that would interfere with revegetation; (iii) Be protected from wind and water erosion... from facilities such as support facilities and preparation plants and where stockpiling of materials...

30 CFR 816.22 - Topsoil and subsoil.

Code of Federal Regulations, 2010 CFR

2010-07-01

... site of small structures, such as power poles, signs, or fence lines; or (ii) Will not destroy the... unnecessary compaction that would interfere with revegetation; (iii) Be protected from wind and water erosion... from facilities such as support facilities and preparation plants and where stockpiling of materials...

Climate change and potential reversal of regime shifts in desrt ecosystems

USDA-ARS?s Scientific Manuscript database

Globally, regime shifts from grasslands to shrublands (i.e., desertification) in arid and semiarid ecosystems are thought to be irreversible, similar to state changes in other ecosystems. The consequences of desertification, including loss of soil and nutrients to wind and water erosion, reductions ...

Categorization of erosion control matting.

DOT National Transportation Integrated Search

2012-05-29

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

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.

Post-wildfire soil erosion in the Mediterranean: Review and future research directions

NASA Astrophysics Data System (ADS)

Shakesby, R. A.

2011-04-01

Wildfires increased dramatically in frequency and extent in the European Mediterranean region from the 1960s, aided by a general warming and drying trend, but driven primarily by socio-economic changes, including rural depopulation, land abandonment and afforestation with flammable species. Published research into post-wildfire hydrology and soil erosion, beginning during the 1980s in Spain, has been followed by studies in other European Mediterranean countries together with Israel and has now attained a sufficiently large critical mass to warrant a major review. Although variations in climate, vegetation, soil, topography and fire severity cause differences in Mediterranean post-wildfire erosion, the long history of human landscape impact up to the present day is responsible for some its distinctive characteristics. This paper highlights these characteristics in reviewing wildfire impacts on hydrology, soil properties and soil erosion by water. The 'mosaic' nature of many Mediterranean landscapes (e.g. an intricate land-use pattern, abandoned terraces and tracks interrupting slopes) may explain sometimes conflicting post-fire hydrological and erosional responses at different sites and spatial scales. First-year post-wildfire soil losses at point- (average, 45-56 t ha - 1 ) and plot-scales (many < 1 t ha - 1 and the majority < 10 t ha - 1 in the first year) are similar to or even lower than those reported for fire-affected land elsewhere or other disturbed (e.g. cultivated) and natural poorly-vegetated (e.g. badlands, rangeland) land in the Mediterranean. The few published losses at larger-scales (hillslope and catchment) are variable. Thin soil and high stone content can explain supply-limited erosion preceding significant protection by recovering vegetation. Peak erosion can sometimes be delayed for years, largely through slow vegetation recovery and temporal variability of erosive storms. Preferential removal of organic matter and nutrients in the commonly thin, degraded soils is arguably just as if not more important than the total soil loss. Aspect is important, with more erosion reported for south- than north-facing slopes, which is attributed to greater fire frequency, slower vegetation recovery on the former and with soil characteristics more prone to erosion (e.g. lower aggregate stability). Post-fire wind erosion is a potentially important but largely neglected process. Gauging the degradational significance of wildfires has relied on comparison with unburnt land, but the focus for comparison should be switched to other agents of soil disturbance and/or currently poorly understood soil renewal rates. Human impact on land use and vegetation may alter expected effects (increased fire activity and post-wildfire erosion) arising from future climatic change. Different future wildfire mitigation responses and likely erosional consequences are outlined. Research gaps are identified, and more research effort is suggested to: (1) improve assessment of post-wildfire erosion impact on soil fertility, through further quantification of soil nutrient depletion resulting from single and multiple fire cycles, and on soil longevity; (2) investigate prescribed fire impacts on carbon release, air pollution and nutrient losses as well as on soil loss; (3) isolate hillslope- and catchment-scale impacts of soil water repellency under Mediterranean post-wildfire conditions; (4) test and refine application of cosmogenic radionuclides to post-wildfire hillslope-scale soil redistribution at different temporal scales; (5) use better temporal resolution of sedimentary sequences to understand palaeofire-erosion-sedimentation links; (6) quantify post-wildfire wind erosion; (7) improve the integration of wildfire into an overall assessment of the processes and impacts of land degradation in the Mediterranean; and (8) raise public awareness of wildfire impact on soil degradation.

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...

A sink for methane on Mars? The answer is blowing in the wind

NASA Astrophysics Data System (ADS)

Knak Jensen, Svend J.; Skibsted, Jørgen; Jakobsen, Hans J.; ten Kate, Inge L.; Gunnlaugsson, Haraldur P.; Merrison, Jonathan P.; Finster, Kai; Bak, Ebbe; Iversen, Jens J.; Kondrup, Jens C.; Nørnberg, Per

2014-07-01

Tumbling experiments that mimic the wind erosion of quartz grains in an atmosphere of 13C-enriched methane are reported. The eroded grains are analyzed by 13C and 29Si solid-state NMR techniques after several months of tumbling. The analysis shows that methane has reacted with the eroded surface to form covalent Si-CH3 bonds, which stay intact for temperatures up to at least 250 °C. The NMR findings offer an explanation for the fast disappearance of methane on Mars.

Study on reinforcement of soil for suppressing fugitive dust by bio-cementitious material

NASA Astrophysics Data System (ADS)

Zhan, Qiwei; Qian, Chunxiang

2017-06-01

Microbial-induced reinforcement of soil, as a new green and environmental-friendly method, is being paid extensive attention to in that it has low cost, simple operation and rapid effects. In this research, reinforcement of soil for suppressing fugitive dust by bio-cementitious material was investigated. Soil cemented by bio-cementitious material had superior mechanical properties, such as hardness, compressive strength, microstructure, wind-erosion resistance, rainfall-erosion resistance and freeze-thaw resistance. The average hardness of sandy soil, floury soil and clay soil is 18.9 º, 25.2 º and 26.1 º, while average compressive strength of samples is 0.43 MPa, 0.54 MPa and 0.69 MPa, respectively; meanwhile, the average calcite content of samples is 6.85 %, 6.09 %, and 5.96 %, respectively. Compared with the original sandy soil, floury soil and clay soil, the porosity decreases by 38.5 %, 33.7 % and 29.2 %. When wind speed is 12 m/s, the mass loss of sandy soil, floury soil and clay soil cemented by bio-cementitious material are all less than 30 g/(m2·h). After three cycles of rainfall erosion of 2.5 mm/h, the mass loss are less than 25 g/(m2·h) and the compressive strength residual ratio are more than 98.0 %. Under 25 cycles of freeze-thaw, the mass loss ratio are less than 3.0 %.

Mars sedimentary rock erosion rates constrained using crater counts, with applications to organic-matter preservation and to the global dust cycle

NASA Astrophysics Data System (ADS)

Kite, Edwin S.; Mayer, David P.

2017-04-01

Small-crater counts on Mars light-toned sedimentary rock are often inconsistent with any isochron; these data are usually plotted then ignored. We show (using an 18-HiRISE-image, > 104-crater dataset) that these non-isochron crater counts are often well-fit by a model where crater production is balanced by crater obliteration via steady exhumation. For these regions, we fit erosion rates. We infer that Mars light-toned sedimentary rocks typically erode at ∼102 nm/yr, when averaged over 10 km2 scales and 107-108 yr timescales. Crater-based erosion-rate determination is consistent with independent techniques, but can be applied to nearly all light-toned sedimentary rocks on Mars. Erosion is swift enough that radiolysis cannot destroy complex organic matter at some locations (e.g. paleolake deposits at SW Melas), but radiolysis is a severe problem at other locations (e.g. Oxia Planum). The data suggest that the relief of the Valles Marineris mounds is currently being reduced by wind erosion, and that dust production on Mars < 3 Gya greatly exceeds the modern reservoir of mobile dust.

Coastal Erosion at Padre Island: Insights from UAV Surveys After Hurricane Harvey

NASA Astrophysics Data System (ADS)

Evans, A.; Wernette, P. A.; Houser, C.

2017-12-01

Hurricane Harvey caused widespread damage to coastal resources and communities when it made landfall north of Corpus Christi, Texas. Located immediately south of Corpus Christi, Padre Island National Seashore (PAIS) sustained significant beach and dune erosion due to strong wind and waves during Hurricane Harvey. This paper presents a post-storm assessment of the geomorphic changes caused Hurricane Harvey at PAIS. Post-storm geomorphology data was collected within 3 days of PAIS re-opening after the storm and again in late October 2017. Data consisted of oblique photographs, shore-normal survey-grade GNSS surveys, and high resolution (1.5 cm) UAV surveys encompassing a 14-km stretch of the beach and dunes. Comparison of post-storm surveys to 2009, 2010, 2011, and 2012 LiDAR series reveals that the beach and dune system sustained substantial erosion during Hurricane Harvey and that erosion is not evenly distributed along the coast. This paper provides valuable insight into how driving on the beach affects patterns of erosion during a storm. Rapid post-storm assessments, such as this paper, also represent valuable baselines for the National Park Service to assess environmental recovery.

Conditions and processes affecting sand resources at archeological sites in the Colorado River corridor below Glen Canyon Dam, Arizona

USGS Publications Warehouse

East, Amy E.; Collins, Brian D.; Sankey, Joel B.; Corbett, Skye C.; Fairley, Helen C.; Caster, Joshua J.

2016-05-17

We conclude that most of the river-corridor archeological sites are at elevated risk of net erosion under present dam operations. In the present flow regime, controlled floods do not simulate the magnitude or frequency of natural floods, and are not large enough to deposit sand at elevations that were flooded at annual to decadal intervals in predam time. For archeological sites that depend upon river-derived sand, we infer elevated erosion risk owing to a combination of reduced sand supply (both fluvial and aeolian) through (1) the lower-than-natural flood magnitude, frequency, and sediment supply of the controlled-flooding protocol; (2) reduction of open, dry sand area available for wind redistribution under current normal (nonflood) dam operations, which do not include flows as low as natural seasonal low flows and do include substantial daily flow fluctuations; and (3) impeded aeolian sand entrainment and transport owing to increased riparian vegetation growth in the absence of larger, more-frequent floods. If dam operations were to increase the supply of sand available for windblown transport—for example, through larger floods, sediment augmentation, or increased fluvial sandbar exposure by low flows—and also decrease riparian vegetation, the prevalence of active aeolian sand could increase over time, and the propensity for unmitigated gully erosion could decrease. Although the evolution of river-corridor landscapes and archeological sites has been altered fundamentally by the lack of large, sediment-rich floods (flows on the order of 5,000 m3/s), some combination of sediment-rich flows above 1,270 m3/s, seasonal flows below 226 m3/s, and riparian-vegetation removal might increase the preservation potential for sand-dependent archeological resources in the Colorado River corridor.

Beach Volume Change Using Uav Photogrammetry Songjung Beach, Korea

NASA Astrophysics Data System (ADS)

Yoo, C. I.; Oh, T. S.

2016-06-01

Natural beach is controlled by many factors related to wave and tidal forces, wind, sediment, and initial topography. For this reason, if numerous topographic data of beach is accurately collected, coastal erosion/acceleration is able to be assessed and clarified. Generally, however, many studies on coastal erosion have limitation to analyse the whole beach, carried out of partial area as like shoreline (horizontal 2D) and beach profile (vertical 2D) on account of limitation of numerical simulation. This is an important application for prevention of coastal erosion, and UAV photogrammetry is also used to 3D topographic data. This paper analyses the use of unmanned aerial vehicles (UAV) to 3D map and beach volume change. UAV (Quadcopter) equipped with a non-metric camera was used to acquire images in Songjung beach which is located south-east Korea peninsula. The dynamics of beach topography, its geometric properties and estimates of eroded and deposited sand volumes were determined by combining elevation data with quarterly RTK-VRS measurements. To explore the new possibilities for assessment of coastal change we have developed a methodology for 3D analysis of coastal topography evolution based on existing high resolution elevation data combined with low coast, UAV and on-ground RTK-VRS surveys. DSMs were obtained by stereo-matching using Agisoft Photoscan. Using GCPs the vertical accuracy of the DSMs was found to be 10 cm or better. The resulting datasets were integrated in a local coordinates and the method proved to be a very useful fool for the detection of areas where coastal erosion occurs and for the quantification of beach change. The value of such analysis is illustrated by applications to coastal of South Korea sites that face significant management challenges.

75 FR 70083 - Emergency Forest Restoration Program and Emergency Conservation Program

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-17

... Iniki in 1993 and Hurricanes Katrina and Rita in 2005 where the extent and magnitude of damage made... rehabilitate farmland damaged by wind erosion, floods, hurricanes, or other natural disasters, and for carrying... the 2008 Farm Bill and the current ECP definition, which includes wildfires, hurricanes or excessive...

Soil water retention within an eroded and restored landscape

USDA-ARS?s Scientific Manuscript database

Significant changes in soil properties and productivity have occurred as a result of intensive row crop production. Many of these changes are related to soil loss from water, wind, and tillage erosion. Soil is lost from convex and steeper landscape positions and deposited in concave lower landscape ...

Using albedo to reform wind erosion modelling, mapping and monitoring

USDA-ARS?s Scientific Manuscript database

Dust emission models are used to assess the impacts of dust on radiative forcing in the atmosphere, cloud formation, nutrient fertilisation and human health. We describe a need in aeolian research to adequately represent the spatial variability and particularly the area average of the key aerodynami...

Modeling vegetation heights from high resolution stereo aerial photography: an application for broad-scale rangeland monitoring

USDA-ARS?s Scientific Manuscript database

Vertical vegetation structure in rangeland ecosystems can be a valuable indicator for monitoring rangeland health or progress toward management objectives because of its importance for assessing riparian areas, post-fire recovery, wind erosion, and wildlife habitat. Federal land management agencies ...

7 CFR 1410.3 - General description.

Code of Federal Regulations, 2012 CFR

2012-01-01

... of the CRP are to cost-effectively reduce water and wind erosion, protect the Nation's long-term... addition to any payments under this part, receive cost-share assistance, rental or easement payments, tax.... However, a participant may not receive or retain CRP cost-share assistance if other Federal cost-share...

7 CFR 1410.3 - General description.

Code of Federal Regulations, 2014 CFR

2014-01-01

... of the CRP are to cost-effectively reduce water and wind erosion, protect the Nation's long-term... addition to any payments under this part, receive cost-share assistance, rental or easement payments, tax.... However, a participant may not receive or retain CRP cost-share assistance if other Federal cost-share...

7 CFR 1410.3 - General description.

Code of Federal Regulations, 2013 CFR

2013-01-01

... of the CRP are to cost-effectively reduce water and wind erosion, protect the Nation's long-term... addition to any payments under this part, receive cost-share assistance, rental or easement payments, tax.... However, a participant may not receive or retain CRP cost-share assistance if other Federal cost-share...

7 CFR 1410.3 - General description.

Code of Federal Regulations, 2011 CFR

2011-01-01

... of the CRP are to cost-effectively reduce water and wind erosion, protect the Nation's long-term... addition to any payments under this part, receive cost-share assistance, rental or easement payments, tax.... However, a participant may not receive or retain CRP cost-share assistance if other Federal cost-share...

7 CFR 1410.3 - General description.

Code of Federal Regulations, 2010 CFR

2010-01-01

... of the CRP are to cost-effectively reduce water and wind erosion, protect the Nation's long-term... addition to any payments under this part, receive cost-share assistance, rental or easement payments, tax.... However, a participant may not receive or retain CRP cost-share assistance if other Federal cost-share...

Resolving dust emission responses to land cover change using an ecological land classification

USDA-ARS?s Scientific Manuscript database

Despite efforts to quantify the impacts of land cover change on wind erosion, assessment uncertainty remains large. We address this uncertainty by evaluating the application of ecological site concepts and state-and-transition models (STMs) for detecting and quantitatively describing the impacts of ...

Patch burn grazing management in a semiarid grassland: Consequences for pronghorn, plains pricklypear and wind erosion

USDA-ARS?s Scientific Manuscript database

Rangeland management strategies that allow for spatial and temporal interactions between fire and herbivores can achieve multiple management goals related to livestock production and wildlife conservation in mesic grasslands and savannas. Less is known about integrated management of herbivores and f...

Canyon Country Ecosystems Research Site

Science.gov Websites

Soil Crust Home Crust 101 Advanced Gallery References CCERS Site Links updated: April 24, 2006 cyanobacteria, algae, lichens and mosses, that stabilize soil against wind and water erosion, enhance water 3400 m, and features a range of climates on both the same and different soil and bedrock substrates

Development of an early warning sensor and network for brown-\\0xAD\\0x2010out conditions.

DOT National Transportation Integrated Search

2016-03-31

Brownout conditions on motorways are caused by windblown dust and sand from upwind areas where : soils are susceptible to wind erosion. Owing in part to prolonged droughts that have dried : soils and denuded vegetation and biological crusts, large, m...

Integration of CFD and Experimental Results at VKI in Low-Speed Aerodynamic Design

DTIC Science & Technology

2007-06-01

erosion in wind tunnel behind the building Today, almost all modern Antartic stations have undergone aerodynamic studies at different stages of design...2] J. Sanz Rodrigo, C. Gorle, J. van Beeck, P. Planquart: Aerodynamic Design of the Princess Elizabeth Antartic Research Station, 17th

Carbon and nitrogen loss in windblown dust on the Columbia Plateau

USDA-ARS?s Scientific Manuscript database

Soil erosion from windstorms may lead to high nutrient loss in fields and cause environmental degradation as a result of suspension in the atmosphere or deposition in surface water systems. In particular, high wind weather events can emit particulates from tilled agricultural soils on the Columbia P...

Threshold friction velocity of soils within the Columbia Plateau

USDA-ARS?s Scientific Manuscript database

Wind erosion only occurs when the friction velocity exceeds the threshold friction velocity (TFV) of the surface. The TFV of loessial soils commonly found across the Columbia Plateau region of the U.S. Pacific Northwest is virtually unknown even though these soils are highly erodible and a source of...

Threshold friction velocity influenced by wetness of soils within the Columbia Plateau

USDA-ARS?s Scientific Manuscript database

Windblown dust impacts air quality in the Columbia Plateau of the U.S. Pacific Northwest. Wind erosion of agricultural lands, which is the predominate source of windblown dust in the region, occurs when the friction velocity exceeds the threshold friction velocity (TFV) of the surface. Soil moisture...

Aerodynamic properties of agricultural and natural surfaces in northwestern Tarim Basin

USDA-ARS?s Scientific Manuscript database

Friction velocity (u*) and aerodynamic roughness (z0) are important parameters that influence soil erosion, but no attempts have been made to quantify these parameters as affected by different land use types in the northwestern Tarim Basin. Wind velocity profiles were measured and used to determine ...

Windblown soil surface characteristics of a wheat-oilseed-fallow cropping system

USDA-ARS?s Scientific Manuscript database

The production of biofuels is dependent upon oilseed feedstocks in the Pacific Northwest United States (PNW), but evidence suggests that wind erosion may be enhanced as a result of growing oilseeds in conventional wheat rotations. Little is known concerning the impact of growing oilseeds on soil cha...

36 CFR 327.30 - Shoreline Management on Civil Works Projects.

Code of Federal Regulations, 2011 CFR

2011-07-01

... excessive siltation, erosion, rapid dewatering, or exposure to high wind, wave, or current action and/or in..., hydro-electric power stations, work areas, water intake structures, etc. No shoreline use permits will... costs, one year permits should be issued only when the location or nature of the activity requires...

USING CONONICAL CORRELATION TO DETECT ASSOCIATION OF LANDSCAPE METRICS WITH WATER BIOLOGICAL AND CHEMICAL PROPERTIES IN SAVANNAH RIVER BASIN

EPA Science Inventory

Surface water quality is related to conditions in the surrounding geophysical environment, including soils, landcover, and anthropogenic activities. For example, clearing vegetation exposes soil to increased water/wind erosion, resulting in increased sediment loads to surface wat...

Nitrogen loss from windblown agricultural soils in the Columbia Plateau

USDA-ARS?s Scientific Manuscript database

Wind erosion of agricultural soils can degrade both air quality and soil productivity in the Columbia Plateau of the Pacific Northwest United States. Soils in the region contain fine particles that, when suspended, are highly susceptible to long range transport in the atmosphere. Nitrogen (N) associ...

Is Corn Stover Harvest Predictable Using Farm Operation, Technology, and Management Variables?

USDA-ARS?s Scientific Manuscript database

Crop residue management, provision of animal feed or bedding, and increased income potential are some reasons for harvesting corn (Zea mays L.) stover. Reasons for not doing so are that crop residue is essential for restoring soil organic matter, protecting against wind and water erosion, and cyclin...

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.

3D Airflow patterns over coastal foredunes: implications for aeolian sediment transport

NASA Astrophysics Data System (ADS)

Jackson, Derek W. T.; Cooper, Andrew G.; Baas, Andreas C. W.; Lynch, Kevin; Beyers, Meiring

2010-05-01

A fundamental criterion for the development of coastal sand dunes is usually highlighted as a significant onshore wind component of the local wind field. The presence of large sand dune systems on coasts where the predominant wind blows offshore is therefore difficult to explain and usually they are attributed to the past occurrence of onshore winds and, by implication, subsequent changes in climate. Recent studies have shown that offshore winds can be deflected or 'steered' by existing dunes so that their direction changes. This can occur to such an extent that a process known as 'flow reversal' can arise, whereby the initially offshore wind actually flows onshore at the beach. This process is important because it can cause sand to be blown from the beach and into the dunes, causing them to grow. This may be central in explaining the presence of extensive dunes on coasts where the dominant wind is offshore, but is also important in how dunes recover after periods of wave erosion during storms. Offshore winds have traditionally been excluded from sediment budget calculations for coastal dunes, but when they do transport sand onshore, this may have been an important oversight leading to significant underestimates of the volume of sand being transported by wind. This work investigates the controls on the processes and the mechanisms involved in deformation of the flow and resulting sediment transport at coastal foredunes in Northern Ireland. We use a combination of field measurement of wind and sediment transport coupled with state-of-the-art aerodynamic modelling using computational fluid dynamics (CFD) and 3-D sonic anemometry. Our working hypothesis is that offshore winds contribute substantially to foredune behaviour on leeside coasts. Preliminary results show strong reverse flow eddies in the seaward side of the foredunes during offshore wind events. These secondary flow reversals have been above velocity threshold and are transport capable. Using CFD modelling across a high resolution LIDAR surface of the dunes and beach we have isolated key areas of wind direction and velocity patterns which are important in aeolian transport budgets. Results are particularly important in post-storm recovery of foredunes damaged under wave action as offshore winds can initiate significant onshore transport, re-supplying the backbeach and foredune zones.

Plants and ventifacts delineate late Holocene wind vectors in the Coachella Valley, USA

USGS Publications Warehouse

Griffiths, P.G.; Webb, R.H.; Fisher, M.; Muth, Allan

2009-01-01

Strong westerly winds that emanate from San Gorgonio Pass, the lowest point between Palm Springs and Los Angeles, California, dominate aeolian transport in the Coachella Valley of the western Sonoran Desert. These winds deposit sand in coppice dunes that are critical habitat for several species, including the state and federally listed threatened species Uma inornata, a lizard. Although wind directions are generally defined in this valley, the wind field has complex interactions with local topography and becomes more variable with distance from the pass. Local, dominant wind directions are preserved by growth patterns of Larrea tridentata (creosote bush), a shrub characteristic of the hot North American deserts, and ventifacts. Exceptionally long-lived, Larrea has the potential to preserve wind direction over centuries to millennia, shaped by the abrasive pruning of windward branches and the persistent training of leeward branches. Wind direction preserved in Larrea individuals and clones was mapped at 192 locations. Compared with wind data from three weather stations, Larrea vectors effectively reflect annual prevailing winds. Ventifacts measured at 24 locations record winds 10° more westerly than Larrea and appear to reflect the direction of the most erosive winds. Based on detailed mapping of local wind directions as preserved in Larrea, only the northern half of the Mission-Morongo Creek floodplain is likely to supply sand to protected U. inornata habitat in the Willow Hole ecological reserve.

How far can we prevent further physical soil degradation in the future?

NASA Astrophysics Data System (ADS)

Horn, Rainer

2017-04-01

Arable as well as forest soils are exposed to increasing external stresses, which coincide with a further and deeper reaching soil degradation, which may result in an aggravation of hydraulic, gaseous, thermal but also physicochemical and chemical soil functions. The decline coincides with a simultaneous reduction in useable land areas and worsens food production amongst others. Therefore, it is mandatory, that stable soil structure from the surface down to depth prevents soil compaction, sustains water infiltration, reduces rates of soil erosion by water and wind in each case to the minimum possible under the soil, terrain, land use, and climatic conditions in which the soils occur. It improves organic carbon storage in soils and optimizes microbial activity and functions. These benefits coincide with sustainable soil properties and soil management systems, which prevent - deep mechanical stress propagation which can cause irreversible soil deformation, - loss of surface soil layers with coinciding organic and mineral nutrient pool available for microbial processing and plant uptake, - Truncation of soil horizons, or damage on private and public infrastructures (roads, houses) and downstream fields. In order to prevent negative impacts on soils, it is recommended, that A) concerning prevention of soil compaction - stresses applied to soils shall not exceed the mechanical soil stability to maintain the actual functioning of chemical, physical and biological processes and to utilize their resilience (i.e. the elasticity), - land use management strategies have to be related to the actual soil properties in order to optimize plant growth, yield, filtering and buffering of infiltrating water, and carbon sequestration. B) soil erosion by - water, wind, and tillage is counteracted by an adequate surface soil stability including a site specific residue management (e.g. conservation tillage), controlled traffic and harvesting, ecological grassland use strategies (e.g. fodder production and harvesting, adequate animal grazing), - wind is furthermore minimized by adequate hedgerow plantations, continuous cover crop growth, optimized particle bindings by water, infiltrating organic acids, appropriate grazing intensity. Agroforestry can be considered as an additional positive measure to reduce soil erosion risks generally and to ameliorate degraded sites. C) -plant cover on slopes remains untouched, overgrazing and consecutive soil homogenization especially under moist climatic conditions must be prevented but adjusted to the actual structure stability of the hillsides. The communication of these findings followed by application of such measures can help farmers and foresters as well as landowners to prevent (further) physical soil degradation in the future.

Orographic precipitation, wind-blown snow, and landscape evolution in glaciated mountain ranges

NASA Astrophysics Data System (ADS)

Brocklehurst, S. H.; Rowan, A. V.; Plummer, M. A.; Foster, D.; Schultz, D. M.; MacGregor, K. R.

2011-12-01

Orographic precipitation and wind-blown snow appear to significantly influence the evolution of glaciated mountain ranges, and in narrow ranges the effect is opposite from orographic precipitation in non-glaciated ranges. While fluvially-eroded ranges tend to be exhumed more on the windward side, glacially-eroded ranges can experience greater erosion on the leeward side. On the timescale of an individual glaciation, the distribution of precipitation and settling is a key component of glacier mass balance and ice extent, while on longer timescales, the interaction of precipitation and topography can play a major role in landscape evolution and range morphology. Numerical modelling of last glacial maximum (LGM) ice extents for catchments on the eastern side of the Southern Alps, New Zealand, highlights the importance of the distribution of precipitation. The accumulation areas of the glaciers would have experienced much greater precipitation than lower elevations, because of the pronounced orographic precipitation gradient, so glacier length is very sensitive to the precipitation distribution employed for any given temperature change. This is particularly challenging given the lack of modern snow monitoring at high altitudes within the Southern Alps, the likelihood of steep accumulation gradients amongst high topography, below the resolution of current datasets, and the difficulty of extrapolating modern values to the LGM. The Sangre de Cristo Range, southern Colorado, and the Bitterroot Range on the Idaho-Montana border both run close to north-south, cross-cutting the prevailing westerly winds. Drainage basins on both sides of the ranges cover similar areas, but moraines are much more substantial on the eastern sides, indicating greater glacial incision, which we suggest at least partly reflects snow blown over the range crest. The Uinta Mountains, Utah, run west-east, parallel to prevailing winds, and show topographic asymmetry across individual catchments, rather than at the range scale. Rapid rock uplift and significant glacial erosion of the north-south Teton Range, Wyoming, has created some of the highest relief in the conterminous US. While an initial topographic asymmetry would have arisen from the tectonic gradient imposed by the extensional Teton Fault on the east side of the range, the topographic asymmetry would have been exaggerated by feedbacks associated with glacial erosion. Slowly-falling snow would have been advected further into the range by prevailing westerlies, which would also have redistributed fallen snow from the subdued topography typical of the headwaters of west-draining basins. Greater topographic shading and cover by rock debris would have mitigated ablation of eastern glaciers bounded by high valley walls. Glacier size, ice flux and erosion would therefore have been enhanced in eastern-draining basins, though only the largest glaciers were capable of eroding at rates that kept pace with rock uplift. Preliminary numerical modelling results are consistent with these inferences of the importance of orographic precipitation and wind-blown snow based on topographic analysis.

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 express in monetary terms. Copyright © 2013 Elsevier B.V. All rights reserved.

Patterns, rates and possible causes of saltmarsh erosion in the Greater Thames area (UK)

NASA Astrophysics Data System (ADS)

van der Wal, Daphne; Pye, Kenneth

2004-08-01

The estuary-dominated coast of the Greater Thames in England has experienced rapid lateral erosion and internal dissection of saltmarshes. This paper provides an overview of saltmarsh development in this area, and re-examines the role of environmental and human forcing factors. It draws on documentary evidence, including historical maps, survey data and time-series data of forcing factors. Lateral marsh retreat began in the 19th century in the Medway and Blackwater Estuaries, followed by other estuaries in the Greater Thames region at the beginning of the 20th century. The outer estuaries and the wider parts of the inner estuaries especially have experienced erosion. Erosion has been modest in wave-sheltered areas, e.g., the Colne and the inner Crouch. In the 1960s and, more widely, the 1970s, a phase of rapid erosion took place, with erosion rates of up to ca. 16 ha year -1 per site, notably along the open coast of Dengie and Foulness, and in the Blackwater and Thames Estuaries. At all sites, vertical sediment accretion was well able to keep up with sea level rise over the past century. Evidence indicates that there may have been several causes for the erosion of saltmarshes. These are notably land claim and embankment construction (increasing the tidal range and current velocities) and a continuous rise of, especially, high and extreme water levels. The latest episode of rapid erosion in the 1970s is largely attributed to changes in the wind/wave climate. For example, erosion at wave-exposed sites coincided with a peak in high magnitude waves combined with a high incidence of southeasterly waves. The study shows that many factors, including natural forcing factors and human activities, have to be taken into account when explaining saltmarsh development.

Soil erosion and the global carbon budget.

PubMed

Lal, R

2003-07-01

Soil erosion is the most widespread form of soil degradation. Land area globally affected by erosion is 1094 million ha (Mha) by water erosion, of which 751 Mha is severely affected, and 549 Mha by wind erosion, of which 296 Mha is severely affected. Whereas the effects of erosion on productivity and non-point source pollution are widely recognized, those on the C dynamics and attendant emission of greenhouse gases (GHGs) are not. Despite its global significance, erosion-induced carbon (C) emission into the atmosphere remains misunderstood and an unquantified component of the global carbon budget. Soil erosion is a four-stage process involving detachment, breakdown, transport/redistribution and deposition of sediments. The soil organic carbon (SOC) pool is influenced during all four stages. Being a selective process, erosion preferentially removes the light organic fraction of a low density of <1.8 Mg/m(3). A combination of mineralization and C export by erosion causes a severe depletion of the SOC pool on eroded compared with uneroded or slightly eroded soils. In addition, the SOC redistributed over the landscape or deposited in depressional sites may be prone to mineralization because of breakdown of aggregates leading to exposure of hitherto encapsulated C to microbial processes among other reasons. Depending on the delivery ratio or the fraction of the sediment delivered to the river system, gross erosion by water may be 75 billion Mg, of which 15-20 billion Mg are transported by the rivers into the aquatic ecosystems and eventually into the ocean. The amount of total C displaced by erosion on the earth, assuming a delivery ratio of 10% and SOC content of 2-3%, may be 4.0-6.0 Pg/year. With 20% emission due to mineralization of the displaced C, erosion-induced emission may be 0.8-1.2 Pg C/year on the earth. Thus, soil erosion has a strong impact on the global C cycle and this component must be considered while assessing the global C budget. Adoption of conservation-effective measures may reduce the risks of C emission and sequester C in soil and biota.

Decoding a Geological Message

NASA Image and Video Library

2017-06-14

A close-up image from NASA's Mars Reconnaissance Orbiter of a recent 150-meter diameter impact crater near Amazonis Mensa and Medusae Fossae is another great example of geologic complexity of Mars. The spider web-like texture of this crater is intriguing. But what does it mean? On Earth, we have many geologic mechanisms that embrace the surface of the planet in an almost constant state of metamorphosis. Although Mars is not nearly as geologically active as Earth, it is still a host to many processes that shape its surface even today (e.g., aeolian modification, periglacial processes, recent impacts, etc.). The appearance of the ejecta of this crater is likely a combination of both the characteristics of the target material it was deposited on, and processes that modified and degraded it over time. When we look to other images in this region we find a similar texture. This texture is referred to as “yardangs” by scientists who study wind erosion. Yardangs are streamlined ridge-and-trough patterns formed by the erosion of wind dominating from a specific direction; in this particular case, from the southeast to the northwest. The specific direction of the winds is supported by regional context images that show many craters in the region have wind streak "tails" that points to the northwest. Craters of this size have been observed to form recently on Mars, so the fact that this crater is modified speaks volumes, and gives us a chance to decode some geological messages from Mars. https://photojournal.jpl.nasa.gov/catalog/PIA21759

Biological soil crusts in deserts: A short review of their role in soil fertility, stabilization, and water relations

USGS Publications Warehouse

Belnap, Jayne

2003-01-01

Cyanobacteria and cyanolichens dominate most desert soil surfaces as the major component of biological soil crusts (BSC). BSCs contribute to soil fertility in many ways. BSC can increase weathering of parent materials by up to 100 times. Soil surface biota are often sticky, and help retain dust falling on the soil surface; this dust provides many plant-essential nutrients including N, P, K, Mg, Na, Mn, Cu, and Fe. BSCs also provide roughened soil surfaces that slow water runoff and aid in retaining seeds and organic matter. They provide inputs of newly-fixed carbon and nitrogen to soils. They are essential in stabilizing soil surfaces by linking soil particles together with filamentous sheaths, enabling soils to resist both water and wind erosion. These same sheaths are important in keeping soil nutrients from becoming bound into plant-unavailable forms. Experimental disturbances applied in US deserts show soil surface impacts decrease N and C inputs from soil biota by up to 100%. The ability to hold aeolian deposits in place is compromised, and underlying soils are exposed to erosion. While most undisturbed sites show little sediment production, disturbance by vehicles or livestock produces up to 36 times more sediment production, with soil movement initiated at wind velocities well below commonly-occurring wind speeds. Winds across disturbed areas can quickly remove this material from the soil surface, thereby potentially removing much of current and future soil fertility. Thus, reduction in the cover of cyanophytes in desert soils can both reduce fertility inputs and accelerate fertility losses.

Cloud forest restoration for erosion control in a Kichwa community of the Ecuadorian central Andes Mountains

NASA Astrophysics Data System (ADS)

Backus, L.; Giordanengo, J.; Sacatoro, I.

2013-12-01

The Denver Professional Chapter of Engineers Without Borders (EWB) has begun conducting erosion control projects in the Kichwa communities of Malingua Pamba in the Andes Mountains south of Quito, Ecuador. In many high elevation areas in this region, erosion of volcanic soils on steep hillsides (i.e., < 40%) is severe and often associated with roads, water supply systems, and loss of native cloud forests followed by burning and cultivation of food crops. Following a 2011 investigation of over 75 erosion sites, the multidisciplinary Erosion Control team traveled to Malingua Pamba in October 2012 to conduct final design and project implementation at 5 sites. In partnership with the local communities, we installed woody cloud forest species, grass (sig-sig) contour hedges, erosion matting, and rock structures (toe walls, plunge pools, bank armoring, cross vanes, contour infiltration ditches, etc.) to reduce incision rates and risk of slump failures, facilitate aggradation, and hasten revegetation. In keeping with the EWB goal of project sustainability, we used primarily locally available resources. High school students of the community grew 5000 native trees and some naturalized shrubs in a nursery started by the school principal, hand weavers produced jute erosion mats, and rocks were provided by a nearby quarry. Where possible, local rock was harvested from landslide areas and other local erosion features. Based on follow up reports and photographs from the community and EWB travelers, the approach of using locally available materials installed by the community is successful; plants are growing well and erosion control structures have remained in place throughout the November to April rainy season. The community has continued planting native vegetation at several additional erosion sites. Formal monitoring will be conducted in October 2013, followed by analysis of data to determine if induced meandering and other low-maintenance erosion control techniques are working as planned. For comparison of techniques, we will consider installing check dams in comparable gullies. The October 2013 project will also focus on training the community how to conduct erosion control site assessments, design site-appropriate structures, and implement erosion control and revegetation plans. Following the training, the community will teach these skills to adjacent villages.

Influence of the sea-ice edge on the Arctic nearshore environment

NASA Astrophysics Data System (ADS)

Barnhart, K. R.; Overeem, I.; Anderson, R. S.

2013-12-01

Coasts form the dynamic interface of the terrestrial and oceanic systems. In the Arctic, and in much of the world, the coast is a zone of relatively high population, infrastructure, biodiversity, and ecosystem services. A significant difference between Arctic and temperate coasts is the presence of sea ice. Sea ice influences Arctic coasts in two main ways: (1) the length of the sea ice-free season controls the length of time over which nearshore water can interact with the land, and (2) the sea ice edge controls the fetch over which storm winds can blow over open water, resulting in changes in nearshore water level and wave field. The resulting nearshore hydrodynamic environment impacts all aspects of the coastal system. Here, we use satellite records of sea ice along with a simple model for wind-driven storm surge and waves to document how changes in the length and character of the sea ice-free season have impacted the nearshore hydrodynamic environment. For our sea ice analysis we primarily use the Bootstrap Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I-SSMIS. We make whole-Arctic maps of sea ice change in the coastal zone. In addition to evaluating changes in length of the sea ice-free season at the coast, we look at changes segmented by azimuth. This allows us to consider changes in the sea ice in the context of the wind field. For our storm surge and wave field analysis we focus on the Beaufort Sea region. This region has experienced some of the greatest changes in both sea ice cover and coastal erosion rates in the Arctic and is anticipated to experience significant change in the future. In addition, the NOAA ESRL GMD has observed the wind field at Barrow since extends to 1977. In our past work on the rapid and accelerating coastal erosion, we have shown that one may model storm surge with a 2D numerical bathystrophic model, and that waves are well represented by the Shore Protection Manual methods for shallow-water fetch-limited waves. We use these models to explore the effect of increasing fetch on water level set up and wave generation. As increasing the fetch is one of the main effects of the changing sea ice cover, this allows us to connect changes in the sea ice cover to changes in the nearshore hydrodynamic environment. The long wind record allows for us to investigate changes in extreme wind and associated storm events. Preliminary analysis of Barrow and Drew Point indicate that at Drew Point the sea ice-free season has expanded by ˜17 days/decade while at Barrow it has expanded by ˜22 days/decade. We find the increase in the number of days when the sea ice edge is far away from the coast makes up a large proportion of the total increase in the duration of the sea ice-free season. For these days the sea ice edge does not provide a limit on the fetch over which water level set up and waves are generated.

[Water and environment in the Southwest of Madagascar].

PubMed

Razanamparany, L

1993-04-01

The dry and arid southwest region of Madagascar is not a desert but resembles the Sahel region of West Africa. The chronic water deficit is aggravated by the heat and constant winds that accelerate evapotranspiration on the permeable soils. The dryness occurs because the southwest region lies outside the main pluviogenic systems. Erosion occurs at all seasons. In the winter the sun and winds are the main causes, while the rare storms are more conducive to run-off and to erosion than to absorption. The acute water shortage in the southwest has prompted hydrogeologic research and well-drilling, but the high salt content of the water and other impurities will be a limiting factor for development of the area. The population of the southwest is extremely mobile. Human settlements are concentrated in the valleys and depressions and along major roads. Customary rights to land under the control of the traditional chiefs regulate tenure in most areas. But especially in the river bottoms, the coming of cash crops cultivated with modern equipment has resulted in significant erosion which has aggravated ecological problems. Accelerating soil degradation has led peasants to extend their lands under cultivation to the detriment of forest cover. Cattle herding remains the principal economic activity in the southwest. Herding has progressed from nomadism to pastoralism, but it remains a sign of power and wealth. Transhumance is the strategy of herders faced with shortages of water and pasturage, demographic pressure, and environmental degradation. Raising of sheep and goats constitutes a supplemental food source, medium of exchange, and form of savings. But angora goats graze on everything in their path, devastating their surrounds. Fear of cattle thefts militates against efforts to improve the quality of the stock. The various problems together have prompted a wasteful exploitation of the forest resources. Development strategies for the area explored by the government have all been forced to consider the high cost of potable water. A water project forms part of the Environmental Plan of Action launched by Madagascar with the assistance of international organizations.

Seafloor environments in Cape Cod Bay, a large coastal embayment

USGS Publications Warehouse

Knebel, H.J.; Rendigs, R. R.; List, J.H.; Signell, R.P.

1996-01-01

Cape Cod Bay is a glacial, semi-enclosed embayment that has a patchy distribution of modern seafloor sedimentary environments of erosion or nondeposition, deposition, and sediment reworking. Sidescan-sonar records and supplemental bathymetric, sedimentary, subbottom, and physical- oceanographic data indicate that the characteristics and distribution of these three categories of bottom environments are controlled by a combination of geologic and oceanographic processes that range from episodic to long-term and from regional to local. (1) Environments of erosion or nondeposition comprise exposares of bedrock, glacial drift, and coarse lag deposits that contain sediments (where present) ranging from boulder fields to gravelly coarse-to-medium sands. These environments are dominant on the shallow margins of the bay (water depths <30 m) where they reflect sediment resuspension, winnowing, and transport during modern northerly storms. (2) Environments of deposition are blanketed by fine-grained sediments ranging from muds to muddy fine sands. These environments are dominant across the floor of the central basin (water depths= 30-60 m) where fine- grained sediments (derived from regional and local sources and emplaced primarily during episodic wind- and density-driven flow) settle through the water column and accumulate under weak bottom currents during nonstorm conditions. (3) Environments of sediment reworking contain patches with diverse textures ranging from gravelly sands to muds. These environments occupy much of the transitional slopes between the margins and the basin floor and reflect a combination of erosion and deposition. The patchy distribution of sedimentary environments within the bay reflects not only regional changes in processes between the margins and the basin but local changes within each part of the bay as well. Small-scale patchiness is caused by local changes in the strengths of wave- and wind-driven currents and (on the margins) by local variations in the supply of fine-grained sediments. This study indicates areas within Cape Cod Bay where fine-grained sediments and associated contaminants are likely to be either moved or deposited. It also provides a guide to the locations and variability of benthic habitats.

Seafloor environments in Cape Cod Bay, a large coastal embayment

USGS Publications Warehouse

Knebel, H.J.; Rendigs, R. R.; List, J.H.; Signell, Richard P.

1996-01-01

Cape Cod Bay is a glacial, semi-enclosed embayment that has a patchy distribution of modern seafloor sedimentary environments of erosion or nondeposition, deposition, and sediment reworking. Sidescan-sonar records and supplemental bathymetric, sedimentary, subbottom, and physical-oceanographic data indicate that the characteristics and distribution of these three categories of bottom environments are controlled by a combination of geologic and oceanographic processes that range from episodic to long-term and from regional to local. (1) Environments of erosion or nondeposition comprise exposures of bedrock, glacial drift, and coarse lag deposits that contain sediments (where present) ranging from boulder fields to gravelly coarse-to-medium sands. These environments are dominant on the shallow margins of the bay (water depths < 30 m) where they reflect sediment resuspension, winnowing, and transport during modern northerly storms. (2) Environments of deposition are blanketed by fine-grained sediments ranging from muds to muddy fine sands. These environments are dominant across the floor of the central basin (water depths = 30–60 m) where fine-grained sediments (derived from regional and local sources and emplaced primarily during episodic wind- and density-driven flow) settle through the water column and accumulate under weak bottom currents during nonstorm conditions. (3) Environments of sediment reworking contain patches with diverse textures ranging from gravelly sands to muds. These environments occupy much of the transitional slopes between the margins and the basin floor and reflect a combination of erosion and deposition.The patchy distribution of sedimentary environments within the bay reflects not only regional changes in processes between the margins and the basin but local changes within each part of the bay as well. Small-scale patchiness is caused by local changes in the strengths of wave- and wind-driven currents and (on the margins) by local variations in the supply of fine-grained sediments.This study indicates areas within Cape Cod Bay where fine-grained sediments and associated contaminants are likely to be either moved or deposited. It also provides a guide to the locations and variability of benthic habitats.

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.

Gust wind tunnel study on ballast pick-up by high-speed trains

NASA Astrophysics Data System (ADS)

Navarro-Medina, F.; Sanz-Andres, A.; Perez-Grande, I.

2012-01-01

This paper describes the experimental setup, procedure, and results obtained, concerning the dynamics of a body lying on a floor, attached to a hinge, and exposed to an unsteady flow, which is a model of the initiation of rotational motion of ballast stones due to the wind generated by the passing of a high-speed train. The idea is to obtain experimental data to support the theoretical model developed in Sanz-Andres and Navarro-Medina (J Wind Eng Ind Aerodyn 98, 772-783, (2010), aimed at analyzing the initial phase of the ballast train-induced-wind erosion (BATIWE) phenomenon. The experimental setup is based on an open circuit, closed test section, low-speed wind tunnel, with a new sinusoidal gust generator mechanism concept, designed and built at the IDR/UPM. The tunnel's main characteristic is the ability to generate a flow with a uniform velocity profile and sinusoidal time fluctuation of the speed. Experimental results and theoretical model predictions are in good agreement.

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

The energetic function of the soil expressed through the potential energy accumulated through humus, the biogeochemical function (the circuit of the nutrient elements) are significantly influenced by its hydrophysical function and especially by the state of the bedding- consolidation, soil capacity of retaining an optimal quantity of water, and then its gradual disponibility for plant consumption. The understanding of soil functions and management including nutrient production, stocking, filtering and transforming minerals, water , organic matter , gas circuit and furnishing breeding material, all make the basis of human activity, Earth's past, present and especially future. The minimum tillage soil systems - paraplow, chisel or rotary grape - are polyvalent alternatives for basic preparation, germination bed preparation and sowing, for fields and crops with moderate loose requirements being optimized technologies for: soil natural fertility activation and rationalization, reduction of erosion, increasing the accumulation capacity for water and realization of sowing in the optimal period. By continuously applying for 10 years the minimum tillage system in a crop rotation: corn - soy-bean - wheat - potato / rape, an improvement in physical, hydro-physical and biological properties of soil was observed, together with the rebuilt of structure and increase of water permeability of soil. The minimum tillage systems ensure an adequate aerial-hydrical regime for the biological activity intensity and for the nutrients solubility equilibrium. The vegetal material remaining at the soil surface or superficially incorporated has its contribution to intensifying the biological activity, being an important resource of organic matter. The minimum tillage systems rebuild the soil structure, improving the global drainage of soil which allows a rapid infiltration of water in soil. The result is a more productive soil, better protected against wind and water erosion and needing less 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.

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

The energetic function of the soil expressed through the potential energy accumulated through humus, the biogeochemical function (the circuit of the nutrient elements) are significantly influenced by its hydrophysical function and especially by the state of the bedding- consolidation, soil capacity of retaining an optimal quantity of water, and then its gradual disponibility for plant consumption. The understanding of soil functions and management including nutrient production, stocking, filtering and transforming minerals, water , organic matter, gas circuit and furnishing breeding material, all make the basis of human activity, Earth's past, present and especially future. The minimum tillage soil systems - paraplow, chisel or rotary grape - are polyvalent alternatives for basic preparation, germination bed preparation and sowing, for fields and crops with moderate loose requirements being optimized technologies for: soil natural fertility activation and rationalization, reduction of erosion, increasing the accumulation capacity for water and realization of sowing in the optimal period. By continuously applying for 10 years the minimum tillage system in a crop rotation: corn - soy-bean - wheat - potato / rape, an improvement in physical, hydro-physical and biological properties of soil was observed, together with the rebuilt of structure and increase of water permeability of soil. The minimum tillage systems ensure an adequate aerial-hydrical regime for the biological activity intensity and for the nutrients solubility equilibrium. The vegetal material remaining at the soil surface or superficially incorporated has its contribution to intensifying the biological activity, being an important resource of organic matter. The minimum tillage systems rebuild the soil structure, improving the global drainage of soil which allows a rapid infiltration of water in soil. The result is a more productive soil, better protected against wind and water erosion and needing less 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.

Glacial morphology in the Chinese Pamir: Connections among climate, erosion, topography, lithology and exhumation

NASA Astrophysics Data System (ADS)

Schoenbohm, Lindsay M.; Chen, Jie; Stutz, Jamey; Sobel, Edward R.; Thiede, Rasmus C.; Kirby, Benjamin; Strecker, Manfred R.

2014-09-01

Modification of the landscape by glacial erosion reflects the dynamic interplay of climate through temperature, precipitation, and prevailing wind direction, and tectonics through rock uplift and exhumation rate, lithology, and range and fault geometry. We investigate these relationships in the northeast Pamir Mountains using mapping and dating of moraines and terraces to determine the glacial history. We analyze modern glacial morphology to determine glacier area, spacing, headwall relief, debris cover, and equilibrium line altitude (ELA) using the area x altitude balance ratio (AABR), toe-to-headwall altitude ratio (THAR) and toe-to-summit altitude method (TSAM) for 156 glaciers and compare this to lithologic, tectonic, and climatic data. We observe a pronounced asymmetry in glacial ELA, area, debris cover, and headwall relief that we interpret to reflect both structural and climatic control: glaciers on the downwind (eastern) side of the range are larger, more debris covered, have steeper headwalls, and tend to erode headward, truncating the smaller glaciers of the upwind, fault-controlled side of the range. We explain this by the transfer of moisture deep into the range as wind-blown or avalanched snow and by limitations imposed on glacial area on the upwind side of the range by the geometry of the Kongur extensional system (KES). The correspondence between rapid exhumation along the KES and maxima in glacier debris cover and headwall relief and minimums in all measures of ELA suggest that taller glacier headwalls develop in a response to more rapid exhumation rates. However, we find that glaciers in the Muji valley did not extend beyond the range front until at least 43 ka, in contrast to extensive glaciation since 300 ka in the south around the high peaks, a pattern which does not clearly reflect uplift rate. Instead, the difference in glacial history and the presence of large peaks (Muztagh Ata and Kongur Shan) with flanking glaciers likely reflects lithologic control (i.e., the location of crustal gneiss domes) and the formation of peaks that rise above the ELA and escape the glacial buzzsaw.

The Monsoon Erosion Pump and the Indian Monsoon since Eocene

NASA Astrophysics Data System (ADS)

Giosan, L.

2017-12-01

Lack of consensus on the Neogene establishment and evolution of the Indian Monsoon is remarkable after half a century of research. Conflicting interpretations point toward the possibility of periodic decoupling between monsoon winds and monsoon precipitation. Here I introduce the concept of a monsoon erosion pump based on terrestrial and oceanic records reconstructed from recent NGHP and IODP drilling and spanning the last 34 million years in the Bay of Bengal, Arabian and Andaman Seas. From millennial to orbital to tectonic timescales, these records suggest that vegetation land cover interacts and modulates the regime of erosion and weathering under perennial but variable monsoonal rain conditions. Under this new proposed paradigm the Indian monsoon exhibits two distinct flavours during the Neogene that can be largely explained by its heartbeat, or astronomical forcing, mediated by the global glacial state and interacting with the paleogeography of South Asia.

Impact of erosion and accretion on the distribution of enterococci in beach sands.

PubMed

Gast, Rebecca J; Gorrell, Levi; Raubenheimer, Britt; Elgar, Steve

2011-09-15

Bacterial pathogens in coastal sediments may pose a health risk to users of beaches. Although recent work shows that beach sands harbor both indicator bacteria and potential pathogens, it is not known how deep within beach sands the organisms may persist nor if they may be exposed during natural physical processes. In this study, sand cores of approximately 1 m depth were collected at three sites across the beach face in Kitty Hawk, North Carolina before, during and after large waves from an offshore hurricane. The presence of DNA from the fecal indicator bacterium Enterococci was detected in subsamples at different depths within the cores by PCR amplification. Erosion and accretion of beach sand at the three sites also was determined for each sampling day. The results indicate that ocean beach sands with persisting enterococci signals could be exposed and redistributed when wind, waves, and currents cause beach erosion or accretion.

The impact of unconfined mine tailings in residential areas from a mining town in a semi-arid environment: Nacozari, Sonora, Mexico

PubMed Central

Meza-Figueroa, Diana; Maier, Raina M.; de la O-Villanueva, Margarita; Gómez-Alvarez, Agustín; Moreno-Zazueta, Alan; Rivera, Jacinto; Campillo, Alberto; Grandlic, Christopher; Anaya, Ricardo; Palafox-Reyes, Juan

2009-01-01

Past mining activities in northern Mexico left a legacy of delerict landscapes devoid of vegetation and seasonal formation of salt efflorescence. Metal content was measured in mine tailings, efflorescent salts, soils, road dust and residential soils to investigate contamination. Climatic effects such as heavy wind and rainfall events can have great impact on the dispersion of metals in semi-arid areas, since soils are typically sparsely vegetated. Geochemical analysis of this site revealed that even though total metal content in mine tailings was relatively low (e.g. Cu = 1000 mg kg-1), metals including Mn, Ba, Zn, and Cu were all found at significantly higher levels in efflorescence salts formed by evaporation on the tailings impoundment surface following the rainy season (e.g. Cu=68000 mg kg-1). Such efflorescent fine-grained salts are susceptible to wind erosion resulting in increased metal spread to nearby residential soils. Our results highlight the importance of seasonally dependent salt-formation and wind erosion in determining risk levels associated with potential inhalation or ingestion of airborne particulates originating from contaminated sites such as tailings impoundments. In low metal-content mine tailings located in arid and semi-arid environments, efflorescence salts could represent a human health risk and a challenge for plant establishment in mine tailings. PMID:19500816

The impact of unconfined mine tailings in residential areas from a mining town in a semi-arid environment: Nacozari, Sonora, Mexico.

PubMed

Meza-Figueroa, Diana; Maier, Raina M; de la O-Villanueva, Margarita; Gómez-Alvarez, Agustín; Moreno-Zazueta, Alan; Rivera, Jacinto; Campillo, Alberto; Grandlic, Christopher J; Anaya, Ricardo; Palafox-Reyes, Juan

2009-09-01

Past mining activities in northern Mexico left a legacy of delerict landscapes devoid of vegetation and seasonal formation of salt efflorescence. Metal content was measured in mine tailings, efflorescent salts, soils, road dust, and residential soils to investigate contamination. Climatic effects such as heavy wind and rainfall events can have great impact on the dispersion of metals in semi-arid areas, since soils are typically sparsely vegetated. Geochemical analysis of this site revealed that even though total metal content in mine tailings was relatively low (e.g. Cu= 1000 mg kg(-1)), metals including Mn, Ba, Zn, and Cu were all found at significantly higher levels in efflorescence salts formed by evaporation on the tailings impoundment surface following the rainy season (e.g. Cu= 68,000 mg kg(-1)). Such efflorescent fine-grained salts are susceptible to wind erosion resulting in increased metal spread to nearby residential soils. Our results highlight the importance of seasonally dependent salt-formation and wind erosion in determining risk levels associated with potential inhalation or ingestion of airborne particulates originating from contaminated sites such as tailings impoundments. In low metal-content mine tailings located in arid and semi-arid environments, efflorescence salts could represent a human health risk and a challenge for plant establishment in mine tailings.

Replacing fallow with cover crops in a semiarid soil: effects on soil properties

USDA-ARS?s Scientific Manuscript database

Replacement of fallow in crop-fallow systems with cover crops (CCs) may improve soil properties. We assessed whether replacing fallow in no-till winter wheat (Triticum aestivum L.)-fallow with winter and spring CCs for five years reduced wind and water erosion, increased soil organic carbon (SOC), a...

Replacing fallow with cover crops in a semiarid soil:Effects on soil properties

USDA-ARS?s Scientific Manuscript database

Replacement of fallow in crop–fallow systems with cover crops (CCs) may improve soil properties. We assessed whether replacing fallow in no-till winter wheat (Triticum aestivum L.)–fallow with winter and spring CCs for 5 years reduced wind and water erosion, increased soil organic carbon (SOC), and ...

7 CFR 701.5 - Land eligibility.

Code of Federal Regulations, 2010 CFR

2010-01-01

... must determine that land that is the subject of the cost share: (1) Will have new conservation problems..., except for wind erosion, is not of the type likely to recur frequently in the same area; and (iv) Be so... agricultural use. Conservation problems existing prior to the disaster are not eligible for cost-share...

7 CFR 701.105 - Land eligibility.

Code of Federal Regulations, 2014 CFR

2014-01-01

... is the subject of the cost share: (1) Will have new conservation problems caused as a result of a... productive capacity of the land; (iii) Represent unusual damage that, except for wind erosion, is not of the... existing prior to the disaster are not eligible for cost-share assistance. (2) Be physically located in a...

7 CFR 701.105 - Land eligibility.

Code of Federal Regulations, 2012 CFR

2012-01-01

... is the subject of the cost share: (1) Will have new conservation problems caused as a result of a... productive capacity of the land; (iii) Represent unusual damage that, except for wind erosion, is not of the... existing prior to the disaster are not eligible for cost-share assistance. (2) Be physically located in a...

7 CFR 701.105 - Land eligibility.

Code of Federal Regulations, 2013 CFR

2013-01-01

... is the subject of the cost share: (1) Will have new conservation problems caused as a result of a... productive capacity of the land; (iii) Represent unusual damage that, except for wind erosion, is not of the... existing prior to the disaster are not eligible for cost-share assistance. (2) Be physically located in a...

7 CFR 701.105 - Land eligibility.

Code of Federal Regulations, 2011 CFR

2011-01-01

... is the subject of the cost share: (1) Will have new conservation problems caused as a result of a... productive capacity of the land; (iii) Represent unusual damage that, except for wind erosion, is not of the... existing prior to the disaster are not eligible for cost-share assistance. (2) Be physically located in a...

Combining Landsat-8 and WorldView-3 data to assess crop residue cover

USDA-ARS?s Scientific Manuscript database

Crop residues on the soil surface contribute to soil quality and form the first line defense against the erosive forces of water and wind. Quantifying crop residue cover on the soil surface after crops are planted is crucial for monitoring soil tillage intensity and assessing the extent of conserva...

Assessing crop residue cover as scene moisture conditions change

USDA-ARS?s Scientific Manuscript database

Crop residue or plant litter is the portion of a crop left in the field after harvest. Crop residues on the soil surface provide a first line of defense against water and wind erosion and reduce the amounts of soil, nutrients, and pesticides that reach streams and rivers. Thus, quantification of cro...

Impact of land use change on wind erosion and dust emission: scenarios from the central US

USDA-ARS?s Scientific Manuscript database

There will be significant changes in land cover and land use throughout the central United States in the coming years, particularly as a result of climate change, changes in US rangeland/farm policy, and increasing exploitation of land-intensive sustainable energy sources. The purpose of this study ...

Military vehicle trafficking impacts on vegetation and soil bulk density at Fort Benning, Georgia

USDA-ARS?s Scientific Manuscript database

Potential increases in wind erosion that might be brought about by military vehicles travelling on off-road sites during training are of concern to the Military establishment. Field studies were conducted in the summer of 2012 at Fort Benning, Georgia. The objective of the experiment was to assess t...

Preliminary results of dust emission data from Yellow Lake Playa, West Texas, USA

USDA-ARS?s Scientific Manuscript database

We investigated the relationship between groundwater and dust emission rates at Yellow Lake, a saline “wet” playa in West Texas with a long history of wind erosion. Deflation of the playa surface has generated lunettes composed of silt-clay aggregates and gypsum. Saltation sensors indicate that most...

Military vehicle trafficking impacts vegetation and soil bulk density at Fort Benning, Georgia

USDA-ARS?s Scientific Manuscript database

Potential increases in wind erosion that might be brought about by military vehicles travelling off-road during training are of concern to the United States military. Field studies were conducted in the summer of 2012 at Fort Benning, Georgia. The objective of the experiment was to assess the traffi...

Dust emissions of organic soils observed in the field and laboratory

USDA-ARS?s Scientific Manuscript database

According to the U.S. Soil Taxonomy, Histosols (also known as organic soils) are soils that are dominated by organic matter (>20% organic matter) in half or more of the upper 80 cm. These soils, when intensively cropped, are subject to wind erosion resulting in loss in crop productivity and degradat...

Fugitive particulate air emissions from off-road vehicle maneuvers at military training lands

USDA-ARS?s Scientific Manuscript database

Military training lands used for off-road vehicle maneuvers may be subject to severe soil loss and air quality degradation as a result of severe wind erosion. The objective of this study was to measure suspended particulate matter resulting from various different vehicle training scenarios. Soil s...

Environmental Processes and Spectral Reflectance Characteristics Associated with Soil Erosion in Desert Fringe Regions

NASA Technical Reports Server (NTRS)

Jacobberger, P. A.

1987-01-01

Results of analysis of spectral variation of sand dunes in El Ghorabi, Bahariya, Egypt; Tombouctou/Azaouad, Mali; and Tsodilo Hills, western Botswana are presented. Seasonal variations in dune extent and location of dune crests and their relationship to such factors as wind and weather variations are emphasized.

Evaluation of MEDALUS model for desertification hazard zonation using GIS; study area: Iyzad Khast plain, Iran.

PubMed

Farajzadeh, Manuchehr; Egbal, Mahbobeh Nik

2007-08-15

In this study, the MEDALUS model along with GIS mapping techniques are used to determine desertification hazards for a province of Iran to determine the desertification hazard. After creating a desertification database including 20 parameters, the first steps consisted of developing maps of four indices for the MEDALUS model including climate, soil, vegetation and land use were prepared. Since these parameters have mostly been presented for the Mediterranean region in the past, the next step included the addition of other indicators such as ground water and wind erosion. Then all of the layers weighted by environmental conditions present in the area were used (following the same MEDALUS framework) before a desertification map was prepared. The comparison of two maps based on the original and modified MEDALUS models indicates that the addition of more regionally-specific parameters into the model allows for a more accurate representation of desertification processes across the Iyzad Khast plain. The major factors affecting desertification in the area are climate, wind erosion and low land quality management, vegetation degradation and the salinization of soil and water resources.

The Impact of Sea Ice Loss on Wave Dynamics and Coastal Erosion Along the Arctic Coast

NASA Astrophysics Data System (ADS)

Overeem, I.; Anderson, R. S.; Wobus, C. W.; Matell, N.; Urban, F. E.; Clow, G. D.; Stanton, T. P.

2010-12-01

The extent of Arctic sea ice has been shrinking rapidly over the past few decades, and attendant acceleration of erosion is now occurring along the Arctic coast. This both brings coastal infrastructure into harm’s way and promotes a complex response of the adjacent landscape to global change. We quantify the effects of declining sea ice extent on coastal erosion rates along a 75-km stretch of coastal permafrost bluffs adjacent to the Beaufort Sea, Alaska, where present-day erosion rates are among the highest in the world at ~14 m yr-1. Our own observations reinforce those of others, and suggest that the rate-limiting process is thermal erosion at the base of the several-meter tall bluffs. Here we focus on the interaction between the nearshore sea ice concentration, the location of the sea ice margin, and the fetch-limited, shallow water wave field, since these parameters ultimately control both sea surface temperatures and the height to which these waters can bathe the frozen bluffs. Thirty years of daily or bi-daily passive microwave data from Nimbus-7 SMMR and DMSP SSM/I satellites reveal that the nearshore open water season lengthened ~54 days over 1979-2009. The open water season, centered in August, expands more rapidly into the fall (September and October~0.92 day yr-1) than into the early summer (July~0.71 days yr-1). Average fetch, defined for our purposes as the distance from the sea ice margin to the coast over which the wind is blowing, increased by a factor 1.7 over the same time-span. Given these time series, we modeled daily nearshore wave heights during the open water season for each year, which we integrated to provide a quantitative metric for the annual exposure of the coastal bluffs to thermal erosion. This “annual wave exposure” increased by 250% during 1979-2009. In the same interval, coastal erosion rates reconstructed from satellite and aerial photo records show less acceleration. We attribute this to a disproportionate extension of the open-water season toward the fall than toward the early summer. This asymmetry fails to tap into the high insolation portion of the summer; expansion into the fall exerts less leverage on coastal change, as sea surface temperatures have significantly declined by late fall. Should the extension of ice-free conditions more strongly advance into the middle of summer, when insolation peaks, we suspect that sea surface temperatures will warm even faster and hence erosion may accelerate yet more strongly.

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 ...

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.

Terrestrial Analogs to Wind-Related Features at the Viking and Pathfinder Landing Sites on Mars

NASA Technical Reports Server (NTRS)

Greeley, Ronald; Bridges, Nathan T.; Kuzmin, Ruslan O.; Laity, Julie E.

2002-01-01

Features in the Mojave Desert and Iceland provide insight into the characteristics and origin of Martian wind-related landforms seen by the Viking and Pathfinder landers. The terrestrial sites were chosen because they exhibit diverse wind features that are generally well understood. These features have morphologies comparable to those on Mars and include origins by deposition and erosion, with erosional processes modifying both soils and rocks. Duneforms and drifts are the most common depositional features seen at the Martian landing sites and indicate supplies of sand-sized particles blown by generally unidirectional winds. Erosional features include lag deposits, moat-like depressions around some rocks, and exhumed soil horizons. They indicate that wind can deflate at least some sediments and that this process is particularly effective where the wind interacts with rocks. The formation of ripples and wind tails involves a combination of depositional and erosional processes. Rock erosional features, or ventifacts, are recognized by their overall shapes, erosional flutes, and characteristic surface textures resulting from abrasion by windblown particles. The physics of saltation requires that particles in ripples and duneforms are predominantly sand-sized (60-2000 microns). The orientations of duneforms, wind tails, moats, and ventifacts are correlated with surface winds above particle threshold. Such winds are influenced by local topography and are correlated with winds at higher altitudes predicted by atmospheric models.

Heavy metal pollution in soils of abandoned mining areas (SE, Spain)

NASA Astrophysics Data System (ADS)

Martínez-Sánchez, M. J.; Pérez-Sirvent, C.; Molina, J.; Tudela, M. L.; Navarro, M. C.; García-Lorenzo, M. L.

2009-04-01

Elevated levels of heavy metals can be found in and around disused metalliferous mines due to discharge and dispersion of mine wastes into nearby agricultural soils, food crops and stream systems. Heavy metals contained in the residues from mining and metallurgical operations are often dispersed by wind and/or water after their disposal. These areas have severe erosion problems caused by wind and water runoff in which soil and mine spoil texture, landscape topography and regional and microclimate play an important role. The present study was carried out in the Cabezo Rajao (La Uni

In search for a compromise between biodiversity conservation and human health protection in restoration of fly ash deposits: effect of anti-dust treatments on five groups of arthropods.

PubMed

Tropek, Robert; Cerna, Ilona; Straka, Jakub; Kocarek, Petr; Malenovsky, Igor; Tichanek, Filip; Sebek, Pavel

2016-07-01

Recently, fly ash deposits have been revealed as a secondary refuge of critically endangered arthropods specialised on aeolian sands in Central Europe. Simultaneously, these anthropogenic habitats are well known for their negative impact on human health and the surrounding environment. The overwhelming majority of these risks are caused by wind erosion, the substantial decreasing of which is thus necessary. But, any effects of anti-dust treatments on endangered arthropods have never been studied. We surveyed communities of five arthropod groups (wild bees and wasps, leafhoppers, spiders, hoverflies and orthopteroid insects) colonising three fly ash deposits in the western Czech Republic. We focused on two different anti-dust treatments (~70 and 100 % cover of fly ash by barren soil) and their comparison with a control of bare fly ash. Altogether, we recorded 495 species, including 132 nationally threatened species (eight of them were considered to be extinct in the country) and/or 30 species strictly specialised to drift sands. Bees and wasps and leafhoppers contained the overwhelming majority of species of the highest conservation interest; a few other important records were also in spiders and orthopteroids. Total soil cover depleted the unique environment of fly ash and thus destroyed the high conservation potential of the deposits. On the other hand, partial coverage (with ~30 % of bare fly ash) still offered habitats for many of the most threatened species, as we showed by both regression and multivariate analyses, with a decrease of wind erosion. This topic still needs much more research interest, but we consider mosaic-like preservation of smaller spots of fly ash as one of the possible compromises between biodiversity and human health.

Control of Lunar and Martian dust--experimental insights from artificial and natural cyanobacterial and algal crusts in the desert of Inner Mongolia, China.

PubMed

Liu, Yongding; Cockell, Charles S; Wang, Gaohong; Hu, Chunxiang; Chen, Lanzhou; De Philippis, Roberto

2008-02-01

Studies on the colonization of environmentally extreme ground surfaces were conducted in a Mars-like desert area of Inner Mongolia, People's Republic of China, with microalgae and cyanobacteria. We collected and mass-cultured cyanobacterial strains from these regions and investigated their ability to form desert crusts artificially. These crusts had the capacity to resist sand wind erosion after just 15 days of growth. Similar to the surface of some Chinese deserts, the surface of Mars is characterized by a layer of fine dust, which will challenge future human exploration activities, particularly in confined spaces that will include greenhouses and habitats. We discuss the use of such crusts for the local control of desert sands in enclosed spaces on Mars. These experiments suggest innovative new directions in the applied use of microbe-mineral interactions to advance the human exploration and settlement of space.

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...

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 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 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 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...

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...

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.

Spatially-resolved mean flow and turbulence help explain observed erosion and deposition patterns of snow over Antarctic sea ice

NASA Astrophysics Data System (ADS)

Trujillo, E.; Giometto, M. G.; Leonard, K. C.; Maksym, T. L.; Meneveau, C. V.; Parlange, M. B.; Lehning, M.

2014-12-01

Sea ice-atmosphere interactions are major drivers of patterns of sea ice drift and deformations in the Polar regions, and affect snow erosion and deposition at the surface. Here, we combine analyses of sea ice surface topography at very high-resolutions (1-10 cm), and Large Eddy Simulations (LES) to study surface drag and snow erosion and deposition patterns from process scales to floe scales (1 cm - 100 m). The snow/ice elevations were obtained using a Terrestrial Laser Scanner during the SIPEX II (Sea Ice Physics and Ecosystem eXperiment II) research voyage to East Antarctica (September-November 2012). LES are performed on a regular domain adopting a mixed pseudo-spectral/finite difference spatial discretization. A scale-dependent dynamic subgrid-scale model based on Lagrangian time averaging is adopted to determine the eddy-viscosity in the bulk of the flow. Effects of larger-scale features of the surface on wind flows (those features that can be resolved in the LES) are accounted for through an immersed boundary method. Conversely, drag forces caused by subgrid-scale features of the surface should be accounted for through a parameterization. However, the effective aerodynamic roughness parameter z0 for snow/ice is not known. Hence, a novel dynamic approach is utilized, in which z0 is determined using the constraint that the total momentum flux (drag) must be independent on grid-filter scale. We focus on three ice floe surfaces. The first of these surfaces (October 6, 2012) is used to test the performance of the model, validate the algorithm, and study the spatial distributed fields of resolved and modeled stress components. The following two surfaces, scanned at the same location before and after a snow storm event (October 20/23, 2012), are used to propose an application to study how spatially resolved mean flow and turbulence relates to observed patterns of snow erosion and deposition. We show how erosion and deposition patterns are correlated with the computed stresses, with modeled stresses having higher explanatory power. Deposition is mainly occurring in wake regions of specific ridges that strongly affect wind flow patterns. These larger ridges also lock in place elongated streaks of relatively high speeds with axes along the stream-wise direction, and which are largely responsible for the observed erosion.