Research of Sand Drift Potential and Wind Conditions in Xilamuren Grassland

2014 ◽  
Vol 955-959 ◽  
pp. 3499-3504
Author(s):  
Zheng Wen Yue ◽  
Rui Qiang Zhang ◽  
Tian Ming Gao

Using the wind data in Xilamuren desert grassland by wind erosion monitoring system to record the years of 2011-2013 as the research foundations, through the statistics of wind and sand transport potential research, from aspect of the characteristics of blown sand environment Xilamuren desert grassland which can be shown the research area are mainly affected by the westerly, Northwest westerly wind or northwest wind three group interaction. The study area of annual sediment potential had mainly effected by westerly and Northwest westerly wind direction ,with wind direction variability index in 0.51°~ 0.61°, belonging to the intermediate ratio range of direction. Annual sediment potential was between 135.95VU ~214.1VU,belongs to the small and medium-sized wind environment. The spring sand transport potential and the resultant sand transporting potential than the other three seasons of sediment transport potential and the resultant sand transporting potential, the main direction of resultant sand transporting potential to Northwest westerly direction, wind direction variability index is relatively large. For spring grassland vegetation coverage rate is lowly, wind speed is large, characteristics of sand is belong to rich material, which should we to retain sand material through the appropriate protective measures to reduce wind erosion. So analyzing the wind regime and the theory of sediment transport potential calculation, provide scientific theoretical basis for the prevention and treatment of sand and harm to the Xilamuren grassland sand flow process.

Forests ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 315 ◽  
Author(s):  
Jieming Zhang ◽  
Guodong Jia ◽  
Ziqiang Liu ◽  
Dandan Wang ◽  
Xinxiao Yu

To assess the ecological effects of poplar stands with different densities and ages, fixed observation sites were established in selected standard forest plots. Daily dynamics of wind speed and sand transport rate were monitored over an erosive period (March to June) in 2017. Soil characteristics were also measured at these plots. Average daily wind speed and average daily wind erosion modulus decreased significantly after the establishment of poplar trees on sandy land, while soil density decreased significantly, soil hardness increased greatly, and soil organic carbon, total N, and available P levels increased significantly. With increasing stand density, average daily wind speed and daily sediment transport firstly decreased and then increased, while the investigated soil nutrients showed the opposite trend. A tree density of 1320–1368 trees·hm−2 significantly reduced surface wind erosion. With the increase in forest age, the average daily wind speed and daily sediment transport declined, while soil physical and chemical properties were gradually improved. At a stand age of 40 years, wind-caused soil erosion significantly reduced. Taking these effects into consideration, the design and management of protective forest systems in arid and semi-arid areas can be greatly improved.


2012 ◽  
Vol 1 (33) ◽  
pp. 50 ◽  
Author(s):  
Le Phuong Dong ◽  
Shinji Sato

Prototype scale laboratory experiments have been conducted to investigate the sheetflow sediment transport of uniform sands under different skewed-asymmetric oscillatory flows. Experimental results reveal that in most of the case with fine sand, the “cancelling effect”, which balances the on-/off-shore net transport under pure asymmetric/skewed flows and results a moderate net transport, was developed for combined skewed-asymmetric flow. However, under some certain conditions (T > 5s) with coarse sands, the onshore sediment transport was enhanced by 50% under combined skewed-asymmetric flows. Sand transport mechanism under oscillatory sheetflow conditions is also studied by comparing the maximum bed shear stress and the phase lag parameter at each half cycle. A comparison of measurements including the new experimental data with a number of practical sand transport formulations shows that the Dong et al. (2013) formulation performs the best in predicting the measured net transport rates over a wide range of experimental conditions


Author(s):  
Sumaiya Sumaiya ◽  
Jonathan A. Czuba ◽  
John T. Schubert ◽  
Scott R. David ◽  
Graham H. Johnston ◽  
...  

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 346 ◽  
Author(s):  
Albert Grases ◽  
Vicente Gracia ◽  
Manuel García-León ◽  
Jue Lin-Ye ◽  
Joan Pau Sierra

Episodic coastal hazards associated to sea storms are responsible for sudden and intense changes in coastal morphology. Climate change and local anthropogenic activities such as river regulation and urban growth are raising risk levels in coastal hotspots, like low-lying areas of river deltas. This urges to revise present management strategies to guarantee their future sustainability, demanding a detailed diagnostic of the hazard evolution. In this paper, flooding and erosion under current and future conditions have been assessed at local scale at the urban area of Riumar, a touristic enclave placed at the Ebro Delta (Spain). Process-based models have been used to address the interaction between beach morphology and storm waves, as well as the influence of coastal environment complexity. Storm waves have been propagated with SWAN wave model and have provided the forcings for XBeach, a 2DH hydro-morphodynamic model. Results show that future trends in sea level rise and wave forcing produce non-linear variations of the flooded area and the volume of mobilized sediment resulting from marine storms. In particular, the balance between flooding and sediment transport will shift depending on the relative sea level. Wave induced flooding and long-shore sand transport seem to be diminished in the future, whereas static sea level flooding and cross-shore sediment transport are exacerbated. Therefore, the characterization of tipping points in the coastal response can help to develop robust and adaptive plans to manage climate change impact in sandy wave dominated coasts with a low-lying hinterland and a complex shoreline morphology.


Author(s):  
Luke S. Blunden ◽  
Stephen G. Haynes ◽  
AbuBakr S. Bahaj

A validated numerical model of tidal flows and sediment transport around the Alderney South Banks was used to investigate the potential effects of large (300 MW) tidal turbine arrays at different locations in Alderney territorial waters. Two methods were used, firstly looking at hydrodynamic changes only and secondly modelling sediment transport over a non-erodible bed. The baseline hydrodynamic model was validated relative to ADCP velocity data collected in the immediate vicinity of the sandbank. Real-world sand transport rates were inferred from sand-wave migrations and agree favourably with sediment transport residuals calculated from model outputs. Outputs from the sediment model reproduced realistic morphological behaviours over the bank. Seventeen different locations were considered; most did not result in significant hydrodynamic changes over the South Banks; however, three array locations were singled out as requiring extra caution if development were to occur. The results provide a case for optimizing the array locations for twin objectives of maximizing array power and minimizing impacts on the sandbanks. This article is part of the theme issue ‘New insights on tidal dynamics and tidal energy harvesting in the Alderney Race’.


1977 ◽  
Vol 14 (8) ◽  
pp. 1906-1915 ◽  
Author(s):  
J. R. Keeley

A series of profiles across Martinique Beach, Nova Scotia, surveyed at monthly intervals between April and October, 1974, showed the formation and subsequent disappearance of large cuspate projections on the beach face. A theoretical model of the distribution of longshore currents on the beach was used to predict the expected positions of convergences and divergences in the longshore sediment transport. The observed projections were found to occur in positions of convergence of waves generated by the southeasterly winds, dominant in the late spring. The disappearance of the cusps was associaled with the seasonal veering of wind direction to the southwest as summer advanced.The size of the seasonal changes in beach profile suggests that the morphology of Martinique Beach is controlled primarily by storm waves.


2014 ◽  
Vol 641-642 ◽  
pp. 25-28
Author(s):  
Shao Yun Deng

The author had given a brief introduction of Tarim River, and the analysis of its water network and the surrounding environmental features, and a few important representative of Tarim River tributaries and the main stream of the four major hydrological stations measured runoff for many years, the annual runoff, the average annual sediment load, the annual sediment load, the annual average sediment concentration, the annual sediment concentration, the average annual sediment transport modulus, the annual sediment transport modulus index data were analyzed. And on this basis, the author had given the further analysis of Tarim River stream sediment distribution characteristics, and had described the sediment source and characteristics of Tarim River.


2012 ◽  
Vol 37 (15) ◽  
pp. 1661-1677 ◽  
Author(s):  
Bernard O. Bauer ◽  
Robin G. D. Davidson-Arnott ◽  
Ian J. Walker ◽  
Patrick A. Hesp ◽  
Jeff Ollerhead

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