Effects of Vegetation Cover on Runoff and Sediment in Field Prototype Slope by Experimental

2012 ◽  
Vol 518-523 ◽  
pp. 4707-4711 ◽  
Author(s):  
Chun Xia Yang ◽  
Pei Qing Xiao ◽  
Bin Zhen ◽  
Zhen Zhou Shen ◽  
Li Li
Keyword(s):  
Ecological Restoration ◽  
Negative Correlation ◽  
Sediment Yield ◽  
Vegetation Cover ◽  
Stable State ◽  
Slope Gradient ◽  
Infiltration Rates ◽  
Runoff Sediment ◽  
Artificial Grass ◽  
The Relationship

The characteristics as well as the correlation between runoff and erosion was studied under 3 kinds of cover conditions of bare-slope, artificial grass slope and ecological-restoration slope with 20°slope gradient by runoff scouring intensities of 9l/min. The results showed that: (1) Sediment yield which sourced from artificial grass slope and ecological-restoration slope was separately decreased by 95% and 98% than bare slope, and the runoff reduced by 20% and 50% than bare slope respectively; The infiltration rates of the two kinds of grass slope were higher than the bare slope by 38.32% to 51.10% and 114%; (2) Sediment and runoff process showed that the stable state appeared respectively at 26min, 18min and 6min under bare slope, artificial grass slope and ecological-restoration slope, the amount of runoff was bare slope> artificial grass slope > ecological-restoration slope. (3) For bare slope and artificial grass slope, the relationship between sediment and runoff, sediment and the drag coefficient which both showed a negative correlation, but the correlation which from the ecological-restoration slope wasn’t obvious, so, further studies should carry out to promote runoff-sediment relations on ecological-restoration slope.

scholarly journals Understanding the factors influencing rill erosion on roadcuts in the south eastern region of South Africa

Solid Earth ◽  
2015 ◽  
Vol 6 (2) ◽  
pp. 633-641 ◽  
Author(s):  
K. E. Seutloali ◽  
H. R. Beckedahl
Keyword(s):  
South Africa ◽  
Vegetation Cover ◽  
Site Effects ◽  
Eastern Region ◽  
Rill Erosion ◽  
Economic Costs ◽  
Slope Gradient ◽  
Factors Influencing ◽  
Relationship Of ◽  
The Relationship

Abstract. Erosion on roadcuts is a concern due to the potential of causing environmental degradation, which has significant economic costs. It is therefore critical to understand the relationship between roadcut characteristics and soil erosion for designing roadcuts that are less vulnerable to erosion and to help road rehabilitation works. This study investigated the characteristics (i.e. gradient, length, percentage of vegetation cover and soil texture) of degraded (i.e. with rills) and non-degraded roadcuts (i.e. without rills) and explored the relationship of the roadcut characteristics with the dimensions (widths and depths) of the rills. Degraded roadcuts were steep (52.21°), long (10.70 m) and had a low percentage of vegetation cover (24.12) when compared to non-degraded roadcuts which had a gradient of 28.24°, length of 6.38 m and 91.7% of vegetation cover. Moreover, the gradient and percentage of vegetation cover of the roadcut significantly determine the rill dimensions. The widths and depths of the rills increase with the increase in slope gradient and decrease with an increase in percentage of vegetation cover. Moreover, the widths and depths of the rills decreased downslope of the roadcuts. Based on these results, re-vegetation of roadcuts as well as construction of gentle gradients could minimise rill erosion and hence the negative on-site and off-site effects.

scholarly journals Influence of Vegetation Coverage on Hydraulic Characteristics of Overland Flow

Water ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1055
Author(s):  
Zekang Cai ◽  
Jian Wang ◽  
Yushuo Yang ◽  
Ran Zhang
Keyword(s):  
Reynolds Number ◽  
Soil Erosion ◽  
Vegetation Cover ◽  
Overland Flow ◽  
Resistance Coefficient ◽  
Vegetation Coverage ◽  
Hydraulic Characteristics ◽  
The Loess Plateau ◽  
Artificial Grass ◽  
The Relationship

Soil erosion is a major problem in the Loess Plateau (China); however, it can be alleviated through vegetation restoration. In this study, the overland flow on a slope during soil erosion was experimentally simulated using artificial grass as vegetation cover. Nine degrees of vegetation coverage and seven flow rates were tested in combinations along a 12° slope gradient. As the coverage degree increased, the water depth of the overland flow increased, but the flow velocity decreased. The resistance coefficient increased with increasing degree of coverage, especially after a certain point. The resistance coefficient and the Reynolds number had an inverse relationship. When the Reynolds number was relatively small, the resistance coefficient decreased faster; however, when it exceeded 600, the resistance coefficient decreased at a slower rate. A critical degree of vegetation cover was observed in the relationship between the resistance coefficient and submergence degree. When the degree of coverage was greater than 66.42%, the resistance coefficient first decreased and then increased with a higher submergence degree. Finally, the formula for the resistance coefficient under vegetation coverage was derived. This formula has a relatively high accuracy and can serve as a reference for predicting soil erosion.

scholarly journals The relative contributions of slope gradient and vegetation cover on erosion characteristics of riparian slopes along the lower Yellow River, China

2021 ◽  
Author(s):  
Zihao Cao ◽  
Qinghe Zhao ◽  
Shengyan Ding ◽  
Yifan Zhang
Keyword(s):  
Particle Size ◽  
Soil Erosion ◽  
Sediment Yield ◽  
Vegetation Cover ◽  
Yellow River ◽  
Size Composition ◽  
Steep Slope ◽  
Slope Gradient ◽  
Lower Yellow River ◽  
The Lower Yellow River

Slope gradient and vegetation cover play key roles in soil erosion process. Exploring the effects of slope gradient and vegetation cover on runoff and sediment yielding characteristics is therefore of great importance for minimizing soil erosion. In this work, based on field scouring experiments on the riparian slopes of the lower Yellow River, China, variation in total runoff, accumulative runoff sediment concentration, erosion sediment yield, and sediment particle size composition under four slope gradients (5°, 10°, 15°, 20°) and three vegetation cover levels (0%, 15%, 30%) were analyzed. Runoff and sediment yield were greatly influenced by slope gradient at steep slope gradients (15° and 20°), while they were mainly affected by vegetation cover at medium slope gradients (5° and 10°). The main enriched particle size of the eroded sediment showed a trend of first increasing and then decreasing with the increasing slope gradient. There was an interaction between slope gradient and vegetation cover, the effect of vegetation cover on erosion sediment yield weakened gradually with increasing slope gradient (at medium slope gradients of 5° and 10°), while the effect of slope gradient increased at steep slope gradients (15° and 20°).

scholarly journals Assessing the determinants of rill erosion on roadcuts in the south eastern region of South Africa

2015 ◽  
Vol 7 (1) ◽  
pp. 393-417
Author(s):  
K. E. Seutloali ◽  
H. R. Beckedahl
Keyword(s):  
South Africa ◽  
Soil Erosion ◽  
Environmental Degradation ◽  
Vegetation Cover ◽  
Eastern Region ◽  
Rill Erosion ◽  
Economic Costs ◽  
Slope Gradient ◽  
Relationship Of ◽  
The Relationship

Abstract. Erosion on roadcuts is a concern due to potential to cause environmental degradation which has significant economic costs. It is therefore critical to understand the relationship between roadcut characteristics and soil erosion for designing roadcuts that are less vulnerable to erosion and to help road rehabilitation works. This study investigated the characteristics (i.e. gradient, length and percentage of vegetation cover) of degraded (i.e. with rills) and non-degraded roadcuts (i.e. without rills) and explored the relationship of the roadcut characteristics with the dimensions (widths and depths) of the rills. Degraded roadcuts were steep (52.21°), long (10.70 m), and had a low percentage of vegetation cover (24.12) when compared to non-degraded roadcuts which had a gradient of 28.24°, length of 6.38 m and 91.7% of vegetation cover. Moreover, the gradient and percentage of vegetation cover of the roadcuts significantly determined the rill dimensions. The widths and depths of the rills increased with the increase in slope gradient and decreased with an increase in percentage of the vegetation cover. Moreover, the widths and depths of the rills decreased downslope of the roadcuts. Based on these results, re-vegetation of roadcuts as well as construction of gentle gradients could minimise rill erosion and hence the negative onsite and offsite effects.

scholarly journals Optimizing micro watershed management for soil erosion control under various slope gradient and vegetation cover conditions using SWAT modeling

2017 ◽  
Author(s):  
Ghulam Nabi ◽  
Fiaz Hussain ◽  
Ray-Shyan Wu ◽  
Vinay Nangia ◽  
Riffat Bibi ◽  
...  
Keyword(s):  
Soil Erosion ◽  
Watershed Management ◽  
Sediment Yield ◽  
Vegetation Cover ◽  
Soil Conservation ◽  
Swat Model ◽  
Yield Reduction ◽  
Slope Gradient ◽  
Soil And Water ◽  
Stone Structures

Abstract. This study evaluated parameters of soil erosion and optimization of micro watersheds by applying a semidistributed basin-scale Soil and Water Assessment Tool (SWAT) model in various small watersheds of the Chakwal and Attock districts of Pothwar, Pakistan. The model was calibrated and validated on a daily basis for a small catchment (Catchment-25) of the Dhrabi watershed without any soil conservation structures. Statistical measures (R2 and EN-S) were used to evaluate model performance; the model performed satisfactorily well for both surface runoff and sediment yield estimations, with the R2 and EN-S values both being greater than 0.75, during calibration (2009–2010) and validation (2011). The model was applied to various small watershed sites in the Chakwal and Attock districts after successful calibration and validation. Soil erosion estimation was performed at these sites having loose stone soil and water conservation structures and being under various slope gradient and vegetation cover conditions. The structures had significant effects, and the average sediment yield reduction engendered by the loose stone structures at the various sites varied from 54 to 98 %. The sediment yield and erosion reductions were also compared under conditions involving vegetation cover change. Agricultural land with winter wheat crops had a higher sediment yield level than did fallow land with crop residue, which facilitated sediment yield reduction along with the soil conservation structures. Analyzing various slope gradients revealed that all selected sites had a maximum slope area of less than 5 %; stone structures were installed at these sites to reduce sediment yield. Based on slope classification analysis, the model was upscaled for the whole districts of Chakwal and Attock. The results indicated that 60 % of Chakwal (4095 km2) and Attock (3918 km2) by area lies in a slope range of 0–4 %; this thus implies that considerable potential exists for implementing soil conservation measures by installing stone structures. Estimates revealed that minimum sediment yield reductions of 122,850 t year−1 in Chakwal District and 117,540 t year−1 in Attock District could be achieved by installing loose stone structures in 60 % of the agricultural areas of both districts having a slope of 0–4 %; these findings can serve as a reference for policymakers and planners. The overarching findings of this study show that the SWAT model provides reliable results for sediment yield and soil erosion estimation, which can be used in rocky mountainous watersheds for erosion control and watershed management.

387 The moderating effect of emotion regulation strategies in the relationship between insomnia severity and bedtime procrastination

SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A153-A154
Author(s):  
Huisu Jeon ◽  
Sonhye Jeoung ◽  
Goeun Kim ◽  
Hyeyoung An ◽  
Hyojin Nam ◽  
...  
Keyword(s):  
Negative Correlation ◽  
Emotional Regulation ◽  
Significant Negative Correlation ◽  
Moderating Effect ◽  
Active Regulation ◽  
Support Seeking ◽  
Regulation Strategies ◽  
Bedtime Procrastination ◽  
The Relationship ◽  
Insomnia Severity

Abstract Introduction Bedtime Procrastination (BP) is defined as the behavior of going to bed later than intended, despite the absence of external factors. Bedtime procrastination is also prevalent among insomnia patients, and is associated with various sleep problems. Recent studies suggest emotional regulation as a mechanism of the procrastination behavior that is the conceptual foundation of bedtime procrastination. Emotional regulation difficulties are also associated with insomnia, but there is still a lack of research on the relationship between insomnia, emotional regulation strategies and bedtime procrastination. Thus, the study assumed that severity of insomnia would affect bedtime procrastination, and examined the moderating effect of the emotional regulation strategies in this relationship. Methods This study was conducted in 376 adults (mean age 23.73 ±2.14 years, 84.6% females). Participants were asked to answer Bedtime procrastination scale (BPS), an emotional regulation strategy checklist, and the Insomnia severity scale (ISI). Results As a result, a significant positive correlation was found between insomnia severity and bedtime procrastination (r=.286, p<.01), and avoidant/distractive regulation style (r=.101, p<.05). active regulation style (r=-.172, p<.01) and support seeking regulation style (r=-.102, p<.01) showed a significant negative correlation with the severity of insomnia. Bedtime procrastination behavior showed significant negative correlation only with active regulation style (r=-.151, p<.01). Support seeking regulation style moderated the relationship between insomnia and bedtime procrastination behavior (B=.0165, 95%, CI=.0014, .0316). The interaction effect between insomnia and support seeking regulation style was also significant (∆R^2=.0112, p<.05), indicating that the effect of insomnia on bedtime procrastination depends on the level of use of the support seeking regulation style. Conclusion These findings suggest that the level of support seeking regulation style is meaningful in terms of how insomnia affects bedtime procrastination. Support (if any) This work was supported by the Ministry of Education of the Republic of Korea and the National Research Foundation of Korea(NRF-2018S1A5A8026807)

scholarly journals Blood pressure level and laboratory indicators of disease severity in patients with arterial hypertension and COVID-19

2021 ◽  
Vol 28 (Supplement_1) ◽  
Author(s):  
K Popov ◽  
A Novitskiy ◽  
Y Shvarts
Keyword(s):  
Blood Pressure ◽  
Multivariate Analysis ◽  
Arterial Hypertension ◽  
Negative Correlation ◽  
Diastolic Pressure ◽  
Negative Relationship ◽  
Laboratory Parameters ◽  
Acute Period ◽  
Nonparametric Correlation ◽  
The Relationship

Abstract Funding Acknowledgements Type of funding sources: None. Background. Many patients with COVID-19 suffer from arterial hypertension and have marked variations in blood pressure (BP) during the acute period of infection. The reasons for such changes are poorly understood. Purpose. To assess the relationship between the level of BP and the severity of changes in the main clinical and laboratory parameters in patients with arterial hypertension and with a moderate course of COVID-19 at the stage of the height of the disease. Materials and methods. The study included 86 hospitalized patients with verified coronavirus disease of moderate severity: 46 of them were male, the median age was 65 years. Patients received adequate hypertension therapy for a long time. After hospitalization, treatment was adjusted if necessary. The level of laboratory parameters in the acute period of the disease was determined, including the electrolytes, C-reactive protein (CRP), albumin, ferritin, general blood test, etc. BP measured daily. The relationship between laboratory parameters and BP level was evaluated by nonparametric correlation using the Spearman coefficient and multivariate analysis based on the "generalized nonlinear model". Results. In 67.44% of patients with hypertension, an elevated BP level (>140/90) was observed against the background of moderate COVID-19. There was a significant negative correlation between the levels of CRP and BP throughout the stay in the hospital, the most significant is the 5th day of hospitalization. At the same time, a slightly stronger relationship is observed with diastolic BP (r = -0.4425) than with systolic BP (r = -0.3525). A similar trend is observed in all BP measurements. Besides, a negative correlation was found between potassium levels and BP values. The strongest association of potassium levels is with systolic BP on the day of hospitalization (r = -0.4850) and diastolic pressure on the 1st day of hospitalization (r = -0.3561). Multivariate analysis confirmed independent and reliable "influence" of CRP (p = 0.00018) and potassium (p = 0.03921) as independent predictors of diastolic pressure. Conclusions. Most patients with hypertension and moderate COVID-19 have elevated BP levels. There is a statistically significant negative relationship between the values of BP and levels of CRP and potassium. The obtained data may correspond to the existing hypothesis about the significant role of the kinin–kallikrein system in the pathogenesis of COVID-19.

Evolutionary game analysis of information sharing by institutional investors

2021 ◽  
pp. 1-9
Author(s):  
Hua Li ◽  
Qingqing Lou ◽  
Qiubai Sun ◽  
Bowen Li
Keyword(s):  
Information Sharing ◽  
Institutional Investors ◽  
Information Exchange ◽  
Evolutionary Game ◽  
Stable State ◽  
Point Of View ◽  
Game Model ◽  
Game Analysis ◽  
Relationship Network ◽  
The Relationship

In order to solve the conflict of interests of institutional investors, this paper uses evolutionary game model. From the point of view of information sharing, this paper discusses four different situations. Only when the sum of risk and cost is less than the penalty of free riding, the evolution of institutional investors will eventually incline to the stable state of information sharing. That is, the phenomenon of hugging. The research shows that the institutional investors are not independent of each other, but the relationship network of institutional investors for the purpose of information exchange. The content of this paper enriches the research on information sharing of institutional investors.

scholarly journals Spatial Variation of the Relationship between PM2.5Concentrations and Meteorological Parameters in China

2015 ◽  
Vol 2015 ◽  
pp. 1-15 ◽  
Author(s):  
Gang Lin ◽  
Jingying Fu ◽  
Dong Jiang ◽  
Jianhua Wang ◽  
Qiao Wang ◽  
...  
Keyword(s):  
Negative Correlation ◽  
Meteorological Parameters ◽  
Semiarid Region ◽  
Strong Positive Correlation ◽  
Annual Average ◽  
Strong Negative Correlation ◽  
Positive Correlation ◽  
Humid Region ◽  
The Relationship ◽  
Warm Temperate

Epidemiological studies around the world have reported that fine particulate matter (PM2.5) is closely associated with human health. The distribution of PM2.5concentrations is influenced by multiple geographic and socioeconomic factors. Using a remote-sensing-derived PM2.5dataset, this paper explores the relationship between PM2.5concentrations and meteorological parameters and their spatial variance in China for the period 2001–2010. The spatial variations of the relationships between the annual average PM2.5, the annual average precipitation (AAP), and the annual average temperature (AAT) were evaluated using the Geographically Weighted Regression (GWR) model. The results indicated that PM2.5had a strong and stable correlation with meteorological parameters. In particular, PM2.5had a negative correlation with precipitation and a positive correlation with temperature. In addition, the relationship between the variables changed over space, and the strong negative correlation between PM2.5and the AAP mainly appeared in the warm temperate semihumid region and northern subtropical humid region in 2001 and 2010, with some localized differences. The strong positive correlation between the PM2.5and the AAT mainly occurred in the mid-temperate semiarid region, the humid, semihumid, and semiarid warm temperate regions, and the northern subtropical humid region in 2001 and 2010.

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