Sand Gravel Research Articles

Beetles (Coleoptera) of Peru: A Survey of the Families. Hydraenidae

Diversity in Peru: 2 genera, 13 species. Recognition: Hydraenids, commonly called minute moss beetles, may be recognized by their small size (generally ,3 mm), very short nine-segmented antennae with a five-segmented club, and six or seven abdominal ventrites. Habitat: These beetles are usually found along margins of streams (especially sandy streams), but sometimes along the margins of lentic habitats (including rock pools). Adults often live interstitially among sand grains and gravel, or occupy the region just below the water surface along the shore or on half-submerged rocks. Most species can be collected by the “shore washing” method, in which water is splashed on the shoreline, and flows back into the stream or pond. Beetles are dislodged from the sand and gravel, and float to the surface, where they can be collected with a fine mesh net. Standard aquatic nets often have meshes that are too large, and the hydraenids pass through. Notes: The following list of Hydraenidae is derived from Perkins (1980, 2011). Blackwelder (1944–1957) did not list any species for Peru. There are certainly more species of Hydraenidae to be discovered in Peru.

Turbulence statistics of flow through degraded channel bed of sand–gravel mixture

This paper describes the results of an experimental study on the turbulence characteristics of flow through bed profile of a laboratory channel that was degraded by detachment of its bed material consisting of sand–gravel mixture. The measurements of velocity and turbulence characteristics over the degraded bed profile were made at three locations along the degraded bed profile using an ADV. The maximum value of turbulence intensity and the Reynolds shear stress were found to occur at the level of bed surface existing before the detachment and these values decreased towards the flow surface. The magnitude of turbulence intensities and Reynolds shear stress are observed to reduce, as one moves towards the downstream along the degraded bed profile which signifies that vortex structure weakened by bed profile degradation. Quadrant analysis was performed which demonstrated the importance of ejection and sweep phases in sediment detachment and transport. Highest occurrence probabilities are found for sweep and ejection event. The other two events i.e. outward and inward interactions are found to have very small occurrence on the probabilities. Variation of occurrence probability with hole size (H) is also discussed.

Effect of drip-irrigation with saline water on Chinese rose (Rosa chinensis) during reclamation of very heavy coastal saline soil in a field trial

Drip-irrigation with saline water was used for reclamation of very heavy coastal saline soils and its effects on salt-sensitive plants were also evaluated in a three-year trial in the coastal region of east China. The original soil salinity expressed as electrical conductivity of the saturation paste extract (ECe) was an average of 27.13dS/m in the 0–100cm depth. The experiment included five treatments of salinity levels of 0.8, 3.1, 4.7, 6.3 and 7.8dS/m of irrigation water. Chinese rose (Rosa chinensis), a salt-sensitive species, were planted in the sandy loam soil to determine the effect of saline environment on growth characters and dry matter production. Drip-irrigation had a significant positive impact on salt leaching, and the very highly saline soil became mildly saline after reclamation in root zone of soil profiles irrigated with water of salinity up to 7.8dS/m. An increase in salinity of irrigation water had adverse effects on plant height, stem diameter, survival rate and dry matter production. Root:shoot ratio increased with increasing water salinity. The values of soil-salt tolerance threshold were 2.39dS/m at emergence and 2.78dS/m in the growth period after emergence. The emergence rate and dry mass decreased by 27.39 and 41.19% for each unit of ECe increase in the root zone, respectively. These results implied that drip-irrigation with saline water by controlling soil matric potential under a gravel–sand layer was effective in reclamation of this very heavy coastal saline soil for sensitive species such as Chinese rose.

Sorting of a sand–gravel mixture in a Gilbert‐type delta

AbstractThis paper presents the results of a Gilbert‐type delta progradation experiment within an impoundment created by a dam. The delta was composed of a poorly sorted sand–gravel mixture in a bedload‐dominated environment. The main goal of the paper is to analyse the sorting process of material within the deposit as the delta progrades towards the dam. Bed profile evolution has been documented and the entire delta has been extensively sampled in order to study sorting processes. Longitudinal and vertical sorting mechanisms are illustrated. What is novel in this investigation is the complete record, within an entire deltaic deposit, of the vertical distribution of streamwise sorting in the absence of suspended load. The data presented herein provide a detailed description of sorting processes in a Gilbert‐type delta. The experimental set‐up, the water flow and the sediment feed rate chosen determine the evolution of the delta: it initially progrades with little topset aggradation and degrades afterwards. Experimental results fit well with a previously presented empirical sorting model, despite the fact that the experimental conditions used here were well outside the range of those used to derive that model. The relative coarsening of the upper layers of the delta is found to be related to the slow speed at which the delta progrades, the formation of a mobile armour layer and the erosion of the topset towards the end of the run. Furthermore, a strong correlation between the coarsening of the bottom layer of the delta and its front height has been documented and explained: as the delta gets higher, as there is more space to sort sediment, it is more likely that coarse particles failing near the top of the foreset reach the bottom of the foreset. These findings provide new and useful data documenting sediment sorting in granular, bedload‐dominated deltas.

Reply to the discussion by Ni et al. on “Analysis of the internal stability of granular soils using different methods”

The authors wish to thank the discussers for their interesting comments that allow us to further improve the paper under discussion. The method proposed by the authors (Moraci et al. 2014) summarizes the commonly used criteria to evaluate the internal stability of cohesionless sand–gravel soils (i.e., Kezdi 1969; Sherard 1979; Kenney and Lau 1985, 1986; hereafter referred to as Kezdi, Sherard, and Kenney and Lau, respectively). The results of the method proposed by the authors are obtained as the average of Sherard’s and Kenney and Lau’s methods. Therefore, the authors’ method is conservative for soils for which both methods used provide conservative results. Kezdi’s criterion has not been considered in the reply because it is similar to but more conservative than Sherard’s.

A conceptual approach to model sand–gravel extraction from rivers based on a game theory perspective

Sand–gravel mining is a significant parameter of economic development and social welfare function in modern societies. As demand for aggregate increases in construction industry, conflicts for the availability of the resource and environmental impacts become more intense. The present paper describes the contested status quo in riverbed sand–gravel mining activities with an example from Greece, as a case study. The scope is to propose a methodology about good governance of the mining sector that promotes a sustainable sharing of aggregate resource by securing environment and safekeeping revenues in the mining trade market.

Physical and numerical modeling of an inclined three-layer (silt/gravelly sand/clay) capillary barrier cover system under extreme rainfall

As an extension of the two-layer capillary barrier, a three-layer capillary barrier landfill cover system is proposed for minimizing rainfall infiltration in humid climates. This system consists of a compacted clay layer lying beneath a conventional cover with capillary barrier effects (CCBE), which is in turn composed of a silt layer sitting on top of a gravelly sand layer. To explore the effectiveness of the new system in minimizing rainfall infiltration, a flume model (3.0m×1.0m×1.1m) was designed and set up in this study. This physical model was heavily instrumented to monitor pore water pressure, volumetric water content, surface runoff, infiltration and lateral drainage of each layer, and percolation of the cover system. The cover system was subjected to extreme rainfall followed by evaporation. The experiment was also back-analyzed using a piece of finite element software called CODE_BRIGHT to simulate transient water flows in the test. Based on the results obtained from various instruments, it was found that breakthrough of the two upper layers occurred for a 4-h rainfall event having a 100-year return period. Due to the presence of the newly introduced clay layer, the percolation of the three-layer capillary barrier cover system was insignificant because the clay layer enabled lateral diversion in the gravelly sand layer above. In other words, the gravelly sand layer changed from being a capillary barrier in a convention CCBE cover to being a lateral diversion passage after the breakthrough of the two upper layers. Experimental and back-analysis results confirm that no infiltrated water seeped through the proposed three-layer barrier system. The proposed system thus represents a promising alternative landfill cover system for use in humid climates.

Factors controlling sediment production from a yarding road and its temporal pattern in an abandoned clear-cut plantation forest in the Shirasu (pyroclastic flow deposits) area, Kagoshima Prefecture, Japan

To understand the temporal pattern in sediment production from a yarding road, we investigated sediment yield and grain size composition, and examined the relevant physical factors in an abandoned clear-cut plantation forest, based on the 3-year onsite monitoring in Shirasu area, Kagoshima Prefecture, Japan. Under a given amount and intensity of rainfall, although sediment yield and grain size of the sediment increased with increasing rainfall, they remarkably decreased each year; that is, the annual sediment yield from the yarding road in the first, second and third years were 6.1, 2.7, and 1.4 mm, respectively. With the elapsed year, the proportion of gravel and coarse sand gradually decreased, whereas the proportion of fine sand and silt-clay gradually increased. Dry density of surface layers decreased with increasing vegetation coverage at the survey site each year. Additionally, surface grain size at the rill and inter-rill points gradually increased with the elapsed year. The results indicated that the annual decrease in both sediment yield and its grain size are associated with an increase in soil porosity (i.e., increase in infiltration capacity) due to root development and increased intensity of ground resistance to overland flows and sediment transport following both vegetation growth and surface armouring.

Formation and properties of sediments in constructed wetlands for treatment of domestic wastewater

Sediments formation and biogeochemical properties were studied in an experimental constructed wetland site in Ukraine (“Bioplato”) for treatment of domestic effluents. The wetland, with a capacity of 50 m3 d− 1 of wastewater, consists of vertical and horizontal filtrations units with fine gravel, middle and coarse sand, a subsurface flow unit with natural wetland soil applied, and a septic tank and sludge-drying field. Macrophytes, reed (Phragmites australis), cattail (Typha latifolia) and a number of sedge species (Carex spp.) were planted in the area and dominate the average cover of 85–90%. Treatment efficiency for BOD5 and suspended solids was 93–96%, for COD – 82%, for nutrients – 27–50%, and for pathogenic microorganisms 99.3–99.6%. Sludge was sampled at each unit followed by standard laboratory analyses of its main characteristics: total organic carbon (TOC), total nutrients (N, P), contents of trace elements, abundance of pathogenic microorganisms, and general toxicity. Results confirmed that the top layer of sludge from each unit of wetland could be used as a source of fertilizers for grain and leguminous crops.

Case Study on Soft Foundation of Coastal Saline Soil

Coastal saline soil foundation was consolidated by surcharge preloading method based on the improving constructio technol-ogy. For instance,setting sand gravels separation layer,composite geo-membrane separation layer,improve embankment height, etc. The monitoring results are analyzed including the ground with every soil layer settlement. Combining with the test result of the shear strength of vane shear test and various ion content of soil samples,it is concluded that reinforcement effect of seashore saline soil consolidated by surcharge preloading method,at the same time, exclusion salt and reduce damage of the foundation.

Differences in 10Be concentrations between river sand, gravel and pebbles along the western side of the central Andes

Cosmogenic nuclides in river sediment have been used to quantify catchment-mean erosion rates. Nevertheless, variable differences in 10Be concentrations according to grain size have been reported. We analyzed these differences in eleven catchments on the western side of the Andes, covering contrasting climates and slopes. The data include eight sand (0.5–1 mm) and gravel (1–3 cm) pairs and twelve sand (0.5–1 mm) and pebble (5–10 cm) pairs. The difference observed in three pairs can be explained by a difference in the provenance of the sand and coarser sediment. The other sand–pebble pairs show a lower 10Be concentration in the pebbles, except for one pair that shows similar concentrations. Two sand–gravel pairs show a lower 10Be concentration in the gravel and the other five pairs show a higher 10Be concentration in the gravel. Differences in climate do not reveal a particular influence on the 10Be concentration between pairs. The analysis supports a model where pebbles and gravel are mainly derived from catchment areas that are eroding at a faster rate. The five gravel samples with high 10Be concentrations probably contain gravel that were derived from the abrasion of cobbles exhumed at high elevations. In order to validate this model, further work should test if pebbles are preferentially exhumed from high erosion rate areas, and if the difference between pebbles with high 10Be concentrations and sand decreases when the erosion rate tends to be homogeneous within a catchment.

Logging Response Characteristics for Pore Brine Potassium Reservoir in the West of Qaidam Basin

Pore brine potassium and deep sand gravel layer found is of large size and high economic value liquid potash deposit in western Qaidam basin depression tectonic(Fig.1).Because the reservoir is relatively thick,it is difficult to

Reclamation of very heavy coastal saline soil using drip-irrigation with saline water on salt-sensitive plants

High salt content in soil, poor soil structure and fresh water shortage are the restricting factors for construction of ecological landscapes in coastal regions with very heavy saline silt-soil. The aim of this work was to develop a method to reclamate the very heavy coastal saline soil using drip-irrigation with saline water for salt-sensitive plants. A field experiment with five treatments of salinity levels of 0.8, 3.1, 4.7, 6.3 and 7.8dS/m of irrigation water was imposed in the very heavy saline silt-soil in 2012–2014. The initial soil in experimental plots was tilled and broken, and a gravel–sand layer was created at 120cm depth. Chinese rose (Rosa chinensis) is very sensitive to salt and was chosen as the representative plant. Soil indexes (electrical conductivity of soil saturated extract (ECe), pH and sodium adsorption ratio (SAR)), growth characters and dry matter production of rose were determined. The results showed that the level of salinity in water had no significant effect on salt leaching in the 0–120cm soil profile, and significant effects only occurred in shallow soil layers. ECe and SAR of soil profile decreased with irrigation time, but pH of soil initially increased and then decreased. Rose growth and dry weight decreased with increasing of irrigation water salinity. The values of soil salt tolerance threshold were 2.24dS/m at emergence and 4.48dS/m in the growth period after emergence. The emergence rate decreased by 53.30% for each unit of ECe increase in the root zone, and dry weight decreased to zero when ECe exceeded 5.36dS/m. A regulatory method was scheduled for drip-irrigation of saline water to control the soil matric potential (SMP) under a gravel–sand layer for initially saline soils and was effective in reclamation of very heavy coastal saline soil (silt soil) for sensitive species such as Chinese rose. An SMP higher above −5kPa at 20cm depth under the emitter in the first year and −10kPa in the second year, and 6mm of irrigation water of salinity up to 4.01dS/m can be used for rose drip-irrigation scheduling, while also maintaining a 50% survival rate.

Long-term effects of gravel—sand mulch on soil organic carbon and nitrogen in the Loess Plateau of northwestern China

Gravel-sand mulch has been used for centuries to conserve water in the Loess Plateau of northwestern China. In this study, we assessed the influence of long-term (1996–2012) gravel-sand mulching of cultivated soils on total organic carbon (TOC), light fraction organic carbon (LFOC), microbial biomass carbon (MBC), total organic nitrogen (TON), particulate organic carbon (POC), mineral-associated organic carbon (MOC), permanganate-oxidizable carbon (KMnO4-C), and non-KMnO4-C at 0–60 cm depths. Mulching durations were 7, 11 and 16 years, with a non-mulched control. Compared to the control, there was no significant and consistently positive effect of the mulch on TOC, POC, MOC, KMnO4-C and non-KMnO4-C before 11 years of mulching, and these organic C fractions generally decreased significantly by 16 years. LFOC, TON and MBC to at a 0–20 cm depth increased with increasing mulching duration until 11 years, and then these fractions decreased significantly between 11 and 16 years, reaching values comparable to or lower than those in the control. KMnO4-C was most strongly correlated with the labile soil C fractions. Our findings suggest that although gravel-sand mulch may conserve soil moisture, it may also lead to long-term decreases in labile soil organic C fractions and total organic N in the study area. The addition of manure or composted manure would be a good choice to reverse the soil deterioration that occurs after 11 years by increasing the inputs of organic matter.

Removal of dissolved inorganic phosphorus with modified gravel sand: kinetics, equilibrium, and thermodynamic studies

The sorption of dissolved inorganic phosphorus by modified gravel sand (iron-doped and calcined gravel sand) was studied through kinetic, equilibrium, and thermodynamic experiments. The maximum phosphorus sorption capacity of iron-doped and calcined gravel sand was 1.01 and 2.93 mg g−1, respectively. When the solution pH gradually approached a highly alkaline condition, the phosphorus removal efficiency of iron-doped gravel sand decreased sharply and that of calcined gravel sand increased. With an increase in initial phosphorus concentration, the sorption capacity of calcined gravel sand increased significantly (0.8–3.1 mg g−1), and that of iron-doped gravel sand was relatively constant (1.2 mg g−1). Data from the isotherm experiments were well described by Langmuir isotherm model. Kinetic studies illustrated that the rate of sorption followed both the pseudo-first-order and pseudo-second-order models, and that the pseudo-second-order model could better describe the sorption kinetics. The calculated thermodynamic parameters suggested that the sorption was a feasible or spontaneous (ΔG < 0), entropy-driven (ΔS > 0), and endothermic (ΔH > 0) reaction.

Surface sediment around the Jabuka Islet and the Jabuka Shoal: Evidence of Miocene tectonics in the Central Adriatic Sea

Abstract This paper is conceived as a contribution to understanding the tectonic setting in the Jabuka region in the Central Adriatic Sea, one of the seismically active regions within the Mediterranean. This seismicity is the result of the compressional tectonics within the Adria microplate, accompanied by halokinetic activity. The Jabuka Islet and the Jabuka Shoal appear to be Triassic igneous bodies extruded by diapir tectonics. Sedimentological, mineralogical and micropaleontological analyses of the surface sediments were done to provide insights into the depositional environment around these igneous outcrops. Coarse-grained gravelly sands surrounding the Jabuka Islet and the Jabuka Shoal are composed predominantly of biogenous detritus, containing small amounts of particles derived from igneous rocks. This highly carbonate sediment cover has been formed in the low-energy environment, below wave base and without terrigenous supply from remote areas. A peculiar finding of reworked Lower Miocene foraminiferal assemblage in the recent surface sediment accompanied with re-interpreted seismic profile was used to propose a conceptual geodynamic model for the Jabuka diapir protrusion. It suggested Miocene age for the earliest protrusion of the Jabuka diapir, followed by further Plio-Quaternary growth and shaping. Together with mostly Paleogene fossil calcareous nannoplankton, fossil foraminifera were presumed to have been weathered from the pierced and extruded overburden rocks and admixed to recent, slowly forming carbonate skeletal association, typical for cool-temperate depositional environments.

Synanthedon mesiaeformis (Herrich-Schäffer) nově v České republice a ve Španělsku (Lepidoptera: Sesiidae)

Synanthedon mesiaeformis (Herrich-Schäffer, 1846) has been found in the Czech Republic and in Spain for the first time. The species was found in the south-easternmost part of the Czech Republic, near the town of Břeclav (faunistic quadrat 7267) in May 2008. The holes and pupae were found only in one, solitary growing group of trees about 20 years old. This finding place lies at a distance of more than 250 km from the localities in SW Hungary and about 550 km from the localities in eastern Poland. In June 2008, the species was found also in alders growing in the flat river alluvium on gravel sands between La Jonquera and Figueres in northern Catalonia. This locality is in a close contact with the fin­ding places near Perpignan and Beziers in southern France. The diagnostic morphological characters and bionomics of this species are briefly summarized and figured. The history of its distribution research is recapitulated and the causes of its disjunct range are discussed as follows. The present disjunct range represents a residual of the former distribution over the warmer and moister postglacial period; landscape modifications and elimination of solitary alder trees as „weeds“ from the 18th up to the mid-20th century in large areas of Europe; narrow and partly unknown habitat requirements and specific population ethology; an insufficient level of faunistic investigations in several parts of sou­thern and eastern Europe.

Seabed Mixed Sediment Classification with Multi-beam Echo Sounder Backscatter Data in Jiaozhou Bay

The multi-beam echo sounder system can not only obtain high-precision seabed bathymetry data, but also obtain high-resolution seabed backscatter strength data. A number of studies have applied acoustic remote sensing method to classify seabed sediment type with multi-beam backscatter strength data, and obtained better classification results than the traditional sediment sampling method. However, these studies mainly focus on the single type sediment classification or seabed mixed sediment classification using single beam data, not multi-beam echo sounder data. Based on backscatter strength data by a high-frequency (300 kHz) Simrad EM3000 multi-beam echo sounder and seabed sediment sampling data of Jiaozhou Bay in Qingdao, China, we establish the relation model between seabed backscatter strength and sediment type characteristics after data processing and corrections. The purpose of data processing is to diminish or weaken the influence of local bottom slope and near nadir reflection on backscatter strength data. Processed backscatter strength data through corrections and compensations can better characterize the features of the seabed sediments. Applying the back propagation neural network method based on genetic algorithm, we present a fast and accurate seabed classification method in this paper which could identify not just a single type of sediment-like rock, sand but also mixed types of sediment like sand gravel, clayey silt and sand-silt-clay.

Triaxial shear behavior of a cement-treated sand–gravel mixture

A number of parameters, e.g. cement content, cement type, relative density, and grain size distribution, can influence the mechanical behaviors of cemented soils. In the present study, a series of conventional triaxial compression tests were conducted on a cemented poorly graded sand–gravel mixture containing 30% gravel and 70% sand in both consolidated drained and undrained conditions. Portland cement used as the cementing agent was added to the soil at 0%, 1%, 2%, and 3% (dry weight) of sand–gravel mixture. Samples were prepared at 70% relative density and tested at confining pressures of 50 kPa, 100 kPa, and 150 kPa. Comparison of the results with other studies on well graded gravely sands indicated more dilation or negative pore pressure in poorly graded samples. Undrained failure envelopes determined using zero Skempton's pore pressure coefficient (A¯=0) criterion were consistent with the drained ones. Energy absorption potential was higher in drained condition than undrained condition, suggesting that more energy was required to induce deformation in cemented soil under drained state. Energy absorption increased with increase in cement content under both drained and undrained conditions.

The impact of particle shape on the angle of internal friction and the implications for sediment dynamics at a steep, mixed sand–gravel beach

Abstract. The impact of particle shape on the angle of internal friction, and the resulting impact on beach sediment dynamics, is still poorly understood. In areas characterized by sediments of specific shape, particularly non-rounded particles, this can lead to large departures from the expected sediment dynamics. The steep slope (1 : 10) of the mixed sand–gravel beach at Advocate Harbour is stable in large-scale morphology over decades, despite a high tidal range of 10 m or more, and intense shore-break action during storms. The Advocate sand (d &lt; 2 mm) was found to have an elliptic, plate-like shape (Corey Shape Index, CSI ≈ 0.2–0.6). High angles of internal friction of this material were determined using direct shear, ranging from φ ≈ 41 to 49°, while the round to angular gravel was characterized as φ = 33°. The addition of 25% of the elliptic plate-like sand-sized material to the gravel led to an immediate increase in friction angle to φ = 38°. Furthermore, re-organization of the particles occurred during shearing, characterized by a short phase of settling and compaction, followed by a pronounced strong dilatory behavior and an accompanying strong increase of resistance to shear and, thus, shear stress. Long-term shearing (24 h) using a ring shear apparatus led to destruction of the particles without re-compaction. Finally, submerged particle mobilization was simulated using a tilted tray submerged in a water-filled tank. Despite a smooth tray surface, particle motion was not initiated until reaching tray tilt angles of 31° and more, being &amp;amp;geq;7° steeper than for motion initiation of the gravel mixtures. In conclusion, geotechnical laboratory experiments quantified the important impact of the elliptic, plate-like shape of Advocate Beach sand on the angles of internal friction of both pure sand and sand–gravel mixtures. The resulting effect on initiation of particle motion was confirmed in tilting tray experiments. This makes it a vivid example of how particle shape can contribute to the stabilization of the beach face.