Determination of efficiency of Vaseline slide and Wilson and Cooke sediment traps by wind tunnel experiments

The trap efficiency of a catcher in wind erosion measurements plays a significant role, and in many cases suspension trap efficiencies at high wind velocities are still unknown. The sediment trap efficiency generally changes with particles size and with wind speed. In this study, the efficiency of Vaseline Slide (VS) and Modified Wilson and Cooke (MWAC) catchers were determined with different sand particle sizes (< 50, < 75, 50-75, 200-400, and 400-500 mu m) at a fixed wind speed (13.3 ms(-1)) and with different soil textures at different wind velocities (10.3, 12.3, and 14.3 ms(-1)) in the wind tunnel of the International Center for Eremology (ICE), Ghent University, Belgium. The traps were placed at different heights (4, 6.5, 13, 20, 120, and 192 cm for VS and 1.5, 3, 5, 8, 11, and 30 cm for MWAC) to catch saltating and suspended sediments in a 12-m long, 1.2-m wide and 3.2-m high working section of the wind tunnel. In the sand particle experiments, the efficiency of the VS catcher was 92% for particles smaller than 50 mu m and decreased with increasing particles size, falling to 2.2% for 400-500 mu m particle size at 13.4 ms(-1). However, the MWAC's efficiency was 0% for particles smaller than 50 mu m and increased with increasing particle size to 69.5% at 400-500 mu m. In the experiments with different soil textures, the efficiency of each catcher significantly changed with soil and with wind speed. It also considerably varied with the catchers: for instance, for sand (S), the MWAC efficiency was very high (67.4, 113.4, and 90.5% at 10.3, 12.3, and 14.4 ms(-1), respectively) while the efficiency of VS was relatively very low (5.2, 4.4, and 1.9% at 10.3, 12.3, and 14.4 ms(-1), respectively). Results indicated that the efficiency depends critically on the particle size, type of catcher, and wind speed, and these could be helpful to increase the robustness of wind erosion measurements

Effect of attachment configuration on the trapping efficiency of Vaseline-coated slide catchers for windblown particles

There are various types of the windblown sediment traps developed for wind tunnel and field studies. One of the main supports expected from these traps is in measuring surface dust concentrations to appropriately derive flux equations. The measurement performance and accuracy of a trap is very important and depends strictly upon the physical characteristics and the behaviors of dust grains with air flows. This paper presents the measurement results of static pressure distribution (SPD) of wind flow around Vaseline-coated slide (VCS) catchers with an aim of finding out whether or not particle trapping efficiency (eta) of the VCS is related to the SPD. The SPD was evaluated by a wind reduction coefficient (R (c)) in a series of wind tunnel experiments with different VCS settings which have different attachment configurations on a pole. Three VCS configurations were considered: a configuration on a circular plastic pole (CPP) and two configurations on wooden square poles (WSP1 and WSP2, respectively). Thus, the primary contribution of this work was to experimentally analyze the effect of the different attachment configurations on the SPD, and the secondary objective was to determine the effect of the SPD on the eta. It was shown that spatial correlation and spatial pattern of the R (c) were different in the surrounding area of each configuration, and ANOVA and DUNCAN tests indicated that eta(s) of WSP1, WSP2, and CPP were different at the significant level of P a parts per thousand currency sign 0.05 with the mean of 0.94 +/- A 0.09, 0.63 +/- A 0.14, and 1.13 +/- A 0.07, respectively. Additionally, the amount of PM20, PM40, PM60, PM80, and PM100 trapped by the configurations of WSP1, WSP2, and CPP considerably varied depending upon the particular aerodynamic circumstances associated with every configuration

Holocene alluvial sediment storage in a small river catchment in the loess area of central Belgium

Soil erosion and sediment deposition widely affect landscape development, particularly in erosion-prone areas with loess-derived soils. Nevertheless, until now, few attempts were made to quantify soil losses and sediment storage over long (centennial or millennial) timescales. In this study, the Holocene alluvial sediment storage in a small river catchment (52km(2)) of the Belgian loess belt is estimated, and a preliminary sediment budget for the catchment is presented.status: publishe