Gravel beds can prevent sand-dust emission and weaken sand-dust flux. We used wind-tunnel experiments and field observations on artificial gravel beds above the Mogao Grottoes to quantify their impact. In the report, we identified a significant correlation between gravel roughness and its ability to trap wind-transported sand. The optimal combinations of gravel diameter and coverage were determ...

Soil water retention parameters are critical to quantify flow and solute transport in vadose zone, while the presence of rock fragments remarkably increases their variability. Therefore a novel method for determining water retention parameters of soil-gravel mixtures is required. The procedure to generate such a model is based firstly on the determination of the quantitative relationship betwee...

Contents 1. Introduction 2. Gravelly Beach Morphology 2.1. Gravelly beach profiles 2.2. Berms and the beach step 2.3. Cusps 3. Hydrodynamics of gravel beaches 3.1. Waves 3.2. Swash phase and percolation effects 3.3. Hydrodynamic effects of the beach step 4. Morphosedimentology of Gravel Beaches 4.1. Size and shape sorting 4.2. Measuring gravel size and shape. 4.3. Bluck models of gravel beach s...

Sphericity and roundness have been employed in sedimentological and geomorphological studies to represent the gross shape of a gravel particle. The original complex definitions of gravel sphericity and roundness led to the use of visual charts or simplified parameters. Although the accurate derivation of sphericity requires the surface area of a gravel particle, manual measurement of the area i...

Sediment transport, one of the key processes of river systems, is altered or stopped by dams, leaving lower river reaches barren of sand and gravel, both of which are essential habitat for fish and macroinvertebrates. One way to compensate for losses in sediment is to supplement gravel to river reaches below impoundments. Because gravel addition has become a widespread practice, it is essential...

A man riding a bike crashed against a bridge and fell into a river. He was rescued just before drowning. Chest radiography and CT scan showed gravel filling almost all his bronchial tree. Three hours were necessary to take out all the gravel by rigid bronchoscopy (Figs. 1 and 2). Fig. 1. Frontal CT scan showing gravel blocking the bronchial tree. Only the right upper bronchus lobe is free. Fig....

t The effect of sesquioxidic i i ic gravels (>2 mm size fraction) on phosphorus sorption by two gravelly lateritic soils was investigated by phosphorus sorption experiments, X-ray diffraction, ti , autoradiography and electron microscopy. In one soil the abundance and size of gravels l decreased downslope. As the gravel content of both soils increased (13-61%), ), the proportion of large (>8 mm...

Soil gravel content affects many soil physical properties, as well as crop yield. Little is known regarding the influence of soil gravel content on growth and nutrient uptake of durum wheat (Triticum durum Desf.). The accumulation of nitrogen and phosphorous during the vegetative and reproductive periods and the contribution of pre-anthesis assimilates to grain N and P content have been evaluat...

Gravel bars are characteristic components of river landscapes and are increasingly recognized as key sites for many waterbirds, though detailed studies on the ecological function of gravel bars for waterbirds are rare. In this study, we surveyed the endangered Scaly-sided Merganser Mergus squamatus along a 40 km river section of Yuan River, in Central China, for three consecutive winters. We de...

Through the laboratory experiments, the mechanical properties of sandy gravel are obtained. Then, based on the slump tests, a modified sandy gravel model is developed by PFC (particle flow code of three dimensions), to which relevant microscopic parameters are assigned to numerically simulate the laboratory experiments. The laboratory test results are compared with that of the numerical simulat...