Potential use of BEST® sediment trap in splash-saltation transport process by simultaneous wind and rain tests

The research on wind-driven rain (WDR) transport process of the splash-saltation has increased over the last twenty years as wind tunnel experimental studies provide new insights into the mechanisms of simultaneous wind and rain (WDR) transport. The present study was conducted to investigate the efficiency of the BEST® sediment traps in catching the sand particles transported through the splash-saltation process under WDR conditions. Experiments were conducted in a wind tunnel rainfall simulator facility with water sprayed through sprinkler nozzles and free-flowing wind at different velocities to simulate the WDR conditions. Not only for vertical sediment distribution, but a series of experimental tests for horizontal distribution of sediments was also performed using BEST® collectors to obtain the actual total sediment mass flow by the splash-saltation in the center of the wind tunnel test section. Total mass transport (kg m-2) were estimated by analytically integrating the exponential functional relationship using the measured sediment amounts at the set trap heights for every run. Results revealed the integrated efficiency of the BEST® traps at 6, 9, 12 and 15 m s-1 wind velocities under 55.8, 50.5, 55.0 and 50.5 mm h-1 rain intensities were, respectively, 83, 106, 105, and 102%. Results as well showed that the efficiencies of BEST® did not change much as compared with those under rainless wind condition

The effect of vegetation patterns on Aeolian mass flux at regional scale: a wind tunnel study

Although insight on the effect of vegetation pattern on Aeolian mass transport is essential for re-planting degraded land, only limited knowledge on this effect is available. The objective of this research was to understand the effect of vegetation design on the Aeolian mass flux inside a single land unit and at the borders among land units. A simulation of Atriplex halimus shrubs inside a wind tunnel was made, and sand redistribution was measured after the application of 200-230 seconds wind at a speed of 11 ms-1. The study showed that: 1) sediment maximum transport inside a single land unit is related to the neighboring land units and to the vegetation pattern within both the unit itself and the neighboring land units; 2) the effect of neighboring land units includes the protection effect and the ruling of sediment crossing from one land unit to the neighboring land units; 3) for the designing of re-planting of degraded land the ‘streets’ (zones of erosion areas similar to streets) effect need to be considered; and 4) in addition to the general knowledge needed on the effect of vegetation pattern on the erosion and deposition within an area, it is important to have insight on the redistribution of sediment at small scales upon the aim of the project

The IPBES Conceptual Framework - connecting nature and people

The first public product of the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES) is its Conceptual Framework. This conceptual and analytical tool, presented here in detail, will underpin all IPBES functions and provide structure and comparability to the syntheses that IPBES will produce at different spatial scales, on different themes, and in different regions. Salient innovative aspects of the IPBES Conceptual Framework are its transparent and participatory construction process and its explicit consideration of diverse scientific disciplines, stakeholders, and knowledge systems, including indigenous and local knowledge. Because the focus on co-construction of integrative knowledge is shared by an increasing number of initiatives worldwide, this framework should be useful beyond IPBES, for the wider research and knowledge-policy communities working on the links between nature and people, such as natural, social and engineering scientists, policy-makers at different levels, and decision-makers in different sectors of society

Detachment and sediment transport from interrill areas under wind -driven rain

Wind-driven rain erosion and the combined effect of wind and rain on erosion process has not been studied widely although wind has long been recognized as an important factor in water erosion. A wind-tunnel study under wind-driven rains was conducted to determine the effects of horizontal wind velocity and direction on physical raindrop impact, interrill detachment and transport processes. Windless rains and the rains driven by horizontal wind velocities of 6 ms−1, 10 ms−1, and 14 ms −1 were applied to three agricultural soils packed into a 20 by 55 cm soil pan placed at both windward and leeward slopes of 4.0, 8.5, and 11.3 degrees. Inclined raingauge measurements showed that the impact frequency of wind-driven raindrops on sloping soil surfaces varied extremely depending on wind-velocity and direction. Rain energy was measured by the splash cup method and a kinetic energy sensor. Measurements indicated that an exponential relationship existed between the energy of simulated rainfall and the applied horizontal wind velocity. Soil detachment and rainsplash transport rates were assessed by the amount of splashed particles trapped at set distances on a 7-m uniform slope segment. Different soil detachment rates occurred depending upon wind velocity and direction under wind-driven rains. Parameters such as fluxes of energy and momentum, which are widely used to predict the soil loss in windless rains, were found to be insensitive to this kind of spatial variability in soil detachment. However, introducing angle of rain incidence as a directionally effective parameter significantly improved the ability of rainfall parameters to account for the variations. Accordingly, the parameters based on the normal impact velocity and impact frequency explained ≥82% of the variation in the detachment rates. Airsplash transport was described by relating transport rate to rainfall parameters and wind shear velocity by a log-linear regression technique, and average airsplash trajectory was predicted by the momentum loss. Sediment transport by rain-impacted shallow overland flow was also adequately described by the selected rainfall and flow parameters. Comparing the contribution of airsplash and thin flow transport as sub-processes of interrill erosion, it is concluded that the airsplash is a significant process that should not be neglected in accurately predicting interrill water erosion

Evaluation of field performance of BEST aeolian sediment catcher in sandy-loam soil of arid zone of Turkey

Field measurement of wind erosion is still a great challenge for researchers. In this study, field performance of a newly designed sediment trap BEST (Basaran and Erpul Sediment Trap) was evaluated for the first time and compared with the commonly used Modified Wilson and Cook (MWAC) traps. Experiments were carried out at the Karapinar Research Station of Konya Soil and Water Resources Institute over the 50 x 50 m tilled sandy loam plot. Three wind erosion events occurred during the experiments. A small amount of sediment was trapped by the MWAC traps only at 0.20 m in all three events, and there were not sufficient sediment measurements at the catch heights to obtain vertical mass flux profiles. On the other hand, BEST was able to catch sufficient amount of sediment at each trap height to calculate soil losses from the experimental fields. Besides, an analysis for particle size characteristics by electron microscopy imagery indicated that almost all of the sediment particles trapped by BEST at any height above 0.60 m were smaller than 100 mm. Hereby, during three erosive wind events a better performance of BEST than of MWAC at comparable catch heights was verified

Evaluation of Field Performance of BEST Aeolian Sediment Catcher in Sandy-loam Soil of Arid Zone of Turkey

Field measurement of wind erosion is still a great challenge for researchers. In this study, field performance of a newly designed sediment trap BEST (Basaran and Erpul Sediment Trap) was evaluated for the first time and compared with the commonly used Modified Wilson and Cook (MWAC) traps. Experiments were carried out at the Karapinar Research Station of Konya Soil and Water Resources Institute over the 50 x 50 m tilled sandy loam plot. Three wind erosion events occurred during the experiments. A small amount of sediment was trapped by the MWAC traps only at 0.20 m in all three events, and there were not sufficient sediment measurements at the catch heights to obtain vertical mass flux profiles. On the other hand, BEST was able to catch sufficient amount of sediment at each trap height to calculate soil losses from the experimental fields. Besides, an analysis for particle size characteristics by electron microscopy imagery indicated that almost all of the sediment particles trapped by BEST at any height above 0.60 m were smaller than 100 mm. Hereby, during three erosive wind events a better performance of BEST than of MWAC at comparable catch heights was verified