Variability of shallow overland flow velocity and soil aggregate transport observed with digital videography

2008 ◽  
Vol 22 (20) ◽  
pp. 4035-4048 ◽  
Author(s):  
A. Sidorchuk ◽  
J. Schmidt ◽  
G. Cooper
Keyword(s):  
Flow Velocity ◽  
Overland Flow ◽  
Soil Aggregate ◽  
Digital Videography

scholarly journals Seasonal vegetation and management influence overland flow velocity and roughness in upland grasslands

2020 ◽  
Vol 34 (18) ◽  
pp. 3777-3791
Author(s):  
Stephanie Bond ◽  
Mike J. Kirkby ◽  
Jean Johnston ◽  
Alistair Crowle ◽  
Joseph Holden
Keyword(s):  
Flow Velocity ◽  
Overland Flow

scholarly journals Factors Determining Soil Water Repellency in Two Coniferous Plantations on a Hillslope

Forests ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 730 ◽  
Author(s):  
Moein Farahnak ◽  
Keiji Mitsuyasu ◽  
Kyoichi Otsuki ◽  
Kuniyoshi Shimizu ◽  
Atsushi Kume
Keyword(s):  
Soil Water ◽  
Overland Flow ◽  
Soil Aggregates ◽  
Aggregate Size ◽  
Water Repellency ◽  
Soil Aggregate ◽  
Water Infiltration ◽  
Soil Water Repellency ◽  
Tree Cutting ◽  
Coniferous Plantations

Soil water repellency (SWR) is a cause of low water infiltration, overland flow and soil erosion in mountainous coniferous plantations in Japan. The factors determining SWR intensity were investigated in two coniferous plantations of Chamaecyparis obtusa (Siebold et Zucc.) Endl. and Cryptomeria japonica (L.f.) D. Don, using intact tree plots and cut tree plots on the same hillslope. The SWR of Ch. obtusa plots was stronger than that of Cr. japonica plots. SWR intensity decreased after tree cutting. There were no significant differences in SWR upslope and downslope of individual trees/stumps for both tree species, though areas downslope of individual Ch. obtusa trees had higher SWR intensity than those upslope. SWR intensity and soil aggregate stability were positively correlated in the Ch. obtusa intact tree plot (r = 0.88, p < 0.01), whereas in the cut tree plot, this correlation was weak with no significance (r = 0.29, p = 0.41). Soil aggregate size had a non-significant influence on SWR intensity. These findings suggest that SWR intensity was not related to the soil aggregate size, but SWR intensity seemed have a role in soil aggregation in the Ch. obtusa intact tree plot. Destruction of soil aggregates could occur after tree cutting because of physical disturbances or increased input of different types of organic matter from other vegetation into soil. The presence of Ch. obtusa introduces a source of SWR, although uncertainty remains about how water repellency is distributed around soil aggregates. The distribution pattern of soil water content and soil hydraulic conductivity around Cr. japonica was related to other factors such as the litter layer and non-water-repellant soil.

Experimental study of sediment transport processes and size selectivity of eroded sediment on steep Pisha sandstone slopes

2020 ◽  
Author(s):  
Pan Zhang ◽  
Pingqing Xiao ◽  
Chunxia Yang
Keyword(s):  
Sediment Transport ◽  
Flow Velocity ◽  
Overland Flow ◽  
Yellow River ◽  
Transport Processes ◽  
The Yellow River ◽  
Size Selectivity ◽  
Coarse Sediment ◽  
Sediment Particles ◽  
Slope Flow

&lt;p&gt;The Pisha sandstone area on the Ordos Plateau of China is the primary source of coarse sediment of the Yellow River. Sediment size distribution and selectivity greatly affect sediment transport and deposition. Hence, sediment transport processes and size selectivity by overland flow on Pisha sandstone slopes were investigated in this study. Experiments were run with Pisha sandstone soil (bulk density of 1.35 g/cm&lt;sup&gt;3&lt;/sup&gt;) under rainfall intensities of 87 and 133 mm/h with a 25&amp;#176; slope gradient, and the duration of simulated rainfall is 1 h. Sediment and runoff were sampled at 2-min intervals to examine the size distribution change of the eroded sediment. The particle composition, enrichment rate, fractal dimension, and time distribution characteristics of median grain size (d&lt;sub&gt;50&lt;/sub&gt;) of eroded sediment were comprehensively analyzed. Statistical analyses showed that the erosion process of Pisha sandstone slope mainly transported coarse sediment. More than 40% of eroded sediment particles were coarse sediment, which will become the main sediment in the lower reaches of the Yellow River bed. The particle size of eroded sediment tended to gradually decrease with the continuous rainfall but remained larger than the background value of Pisha sandstone soil after refinement. The fractal dimension was positively correlated with the slope flow velocity, while the d&lt;sub&gt;50&lt;/sub&gt; was negatively correlated with the slope flow velocity. Overall, these findings show a strong relationship between the sediment transport and flow velocity, which indicates that the selectivity and transportation of sediment particles on the Pisha sand slopes is mainly influenced by the hydrodynamic parameters of overland flow. This study provides a methodology and data references for studying the particle selectivity characteristics of eroded sediment and provides a scientific basis for revealing the mechanism of erosion and sediment yield in the Pisha sandstone area of China.&lt;/p&gt;

scholarly journals Overland flow velocity and roughness properties in peatlands

2008 ◽  
Vol 44 (6) ◽  
Author(s):  
Joseph Holden ◽  
Mike J. Kirkby ◽  
Stuart N. Lane ◽  
David G. Milledge ◽  
Chris J. Brookes ◽  
...  
Keyword(s):  
Flow Velocity ◽  
Overland Flow

scholarly journals Using thermal tracers to estimate flow velocities of shallow flows: laboratory and field experiments

2015 ◽  
Vol 63 (3) ◽  
pp. 255-262 ◽  
Author(s):  
Rui L.P. de Lima ◽  
João R.C.B. Abrantes ◽  
João L.M.P. de Lima ◽  
M. Isabel P. de Lima
Keyword(s):  
Flow Velocity ◽  
Field Experiments ◽  
Overland Flow ◽  
Velocity Estimation ◽  
Shallow Flow ◽  
Shallow Flows ◽  
Dye Tracer ◽  
Flow Surface ◽  
Infrared Technology ◽  
Hydrology And Water Resources

Abstract Accurate measurement of shallow flows is important for hydraulics, hydrology and water resources management. The objective of this paper is to discuss a technique for shallow flow and overland flow velocity estimation that uses infrared thermography. Laboratory flumes and different bare, vegetated and paved field surfaces were used to test the technique. Results show that shallow flow surface velocities estimated using thermal tracers and infrared technology are similar to estimates obtained using the Acoustic Doppler Velocimeter; similar results were also obtained for overland flow velocity estimates using thermography, here comparing with the dye tracer technique. The thermographic approach revealed some potential as a flow visualization technique, and leaves space for future studies and research.

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