Sediment Mass Research Articles

Determination of optimal conditions for processing oil bottom sediments using electrohydraulic effect

Currently, there is an interest in effective technologies that cause minimal environmental harm, have low financial costs and allow you to obtain products with high added value. One of the ways to increase the yield of light and medium fractions from oil bottom sediments is to use the electrohydraulic effect. The electrohydraulic phenomenon is a new industrial method of converting electrical energy into mechanical energy, which occurs without the influence of intermediate mechanical links, with high efficiency. Statistical processing of experimental data was carried out with the identification of the optimal mode of the electrohydraulic effect on the destruction of the oil bottom sediment. The influence of various factors is shown (duration of contact, distance between electrodes, amount of added catalyst, capacitance of capacitor and value of applied voltage). The use of the generalized equation made it possible to determine the following optimal conditions for the destruction of the oil bottom sediment using electrohydraulic treatment: duration 7 min, distance 8 mm, amount of added catalyst 1.5 %, capacitance 0.3 μF, applied voltage 14 kV. In terms of the significance of the coefficient (tr), it should be noted that the dominant factors are the distance between the electrodes and the amount of added catalyst. The individual chemical composition of the light and medium fractions of the original oil residue and the processed oil residue was determined. Comparison of the individual chemical composition of fractions up to 200 °С and 200–300 °С, obtained from the oil bottom sediment and from the hydrogenated product, allows to conclude that the electrohydraulic effect has an effective effect on the destruction of the organic mass of the oil bottom sediment. The optimal conditions for electrohydraulic treatment of the oil residue aere established and it is shown that it is possible to utilize the oil bottom sediments

Investigations on River Sediments in Chak Sedimentary Basin, Wardak Province, Afghanistan

This sedimentary is from a largest basin of Afghanistan, which covers an area of 9772 km2. It is located about 80 km, at west side of Kabul. In this research, we studied different types of heavy and light minerals, gravel analysis in river sediments. Logar River is core stream flowing over basin,it carries diverse masses of sediments from dissimilar parts of surroding montians. Further, in the months of summer while snowmelting is started,transfer diverse materials and cause different traces to be made. Area of basin is enclosed by mountain range and separated into two sections,majore part is Khawat Olya and second one is Khawat Sufla. The main aim of study is to characterize different sizes and types of minerals in river load for the previous geological periods. This research is therefore essential to explain different sizes and type of minerals in river sediments, which is no any study has been conducted in the study area. This study found out that the category of sediments is related to the parental materials that are placed in the close mountains such as; gneiss, limestone, and granite, dissimilar varities of conglomerate, slate, schist, reefs, conglomerate and sandston.

Geologic Controls on Erosion Mechanism on the Alaska Beaufort Coast

Two prominent arctic coastal erosion mechanisms affect the coastal bluffs along the North Slope of Alaska. These include the niche erosion/block collapse mechanism and the bluff face thaw/slump mechanism. The niche erosion/block collapse erosion mechanism is dominant where there are few coarse sediments in the coastal bluffs, the elevation of the beach below the bluff is low, and there is frequent contact between the sea and the base of the bluff. In contrast, the bluff face thaw/slump mechanism is dominant where significant amounts of coarse sediment are present, the elevation of the beach is high, and contact between the sea and the bluff is infrequent. We show that a single geologic parameter, coarse sediment areal density, is predictive of the dominant erosion mechanism and is somewhat predictive of coastal erosion rates. The coarse sediment areal density is the dry mass (g) of coarse sediment (sand and gravel) per horizontal area (cm2) in the coastal bluff. It accounts for bluff height and the density of coarse material in the bluff. When the areal density exceeds 120 g cm−2, the bluff face thaw/slump mechanism is dominant. When the areal density is below 80 g cm−2, niche erosion/block collapse is dominant. Coarse sediment areal density also controls the coastal erosion rate to some extent. For the sites studied and using erosion rates for the 1980–2000 period, when the sediment areal density exceeds 120 g cm−2, the average erosion rate is low or 0.34 ± 0.92 m/yr. For sediment areal density values less than 80 g cm−2, the average erosion rate is higher or 2.1 ± 1.5 m/yr.

Evaluation of urban underground space resources in a delta coastal city

In the multi-aquifer and multi-aquitard system of a delta coastal city, urban underground space is filled with soil, sediment, and rock mass, as well as groundwater. Underground space can be created by excavating the layered strata. Urban underground space includes man-made structures, such as piles, underground structures, subway tunnels, etc. It is important to know how to evaluate the number of underground space resources. With Shanghai as background and the Zhongshan park urban plan unit as an example, a three-dimensional geological model for all sediment layers was established based on the geotechnical investigation. The number of existing underground structures was estimated using collected data. An underground space estimation method is introduced. The proportion of different layers was calculated using a geological model that corresponded to the shallow-middle-deep urban underground space conceptual plan, which can be referred to by underground space planning.

When and Where do Free Bars in Estuaries and Tidal Channels Form?

AbstractThe incipient formation of free bars in weakly converging tidal channels and estuaries is mathematically framed within a unified two‐dimensional shallow water and sediment mass balance model. The analysis is driven by the recognition that none of the theoretical models introduced so far account for the spatially varying character of the planform morphology, which characterizes estuaries and creeks forming networks in coastal wetlands and in the tide‐dominated reaches of deltas. The problem is tackled by means of a linear stability analysis, by observing that width variations act on a spatial scale that is typically much longer than bars wavelength, allowing for an analytical treatment of the governing system of equations. We focus on two limit cases: first, the river transition into a micro‐tidal sea (estuarine case); second, a tidal channel in the absence of a fluvial supply of freshwater and sediment (coastal case). In the estuarine case, bars arise as a result of an intrinsic instability of the equilibrium state. Width increases toward the mouth leading to channel shallowing, which in turn promotes the development of multiple bars. This effect is partially counteracted by the channel deepening produced by the tidal action, which tends to reduce bar growth and migration rate. In the coastal case, tidal bars form far from the equilibrium state of the system, adapting instantaneously to the evolving bed profile, which in turn affects channel flow conditions. Noteworthy, the model suggests that the spatial‐temporal distribution of bars observed in nature reflects the evolutionary history of the system.

The influence mechanism of the main suspended particles of Yellow River sand on the emitter clogging − An attempt to improve the irrigation water utilization efficiency in Yellow River basin

The existence of suspended particles in water poses a great challenge to the adaptability of drip irrigation technology. To explore the differences in emitter clogging caused by irrigation water containing various suspended solids, this research used irrigation water containing Yellow River sand, quartz sand, and sodium bentonite as the main suspended particles (designated HW, SW and BW, respectively) to conduct a short-period emitter anti-clogging test and particle settlement test in static water. The results showed that the type of suspended particles had a very significant impact on the relative flow rate (Dra) of the emitter (P < 0.01). Emitter clogging was the most serious in the HW treatment, followed by the SW treatment, and emitters in the BW treatment had the lowest clogging degree. The clogging substance formed in the HW treatment exhibited a compact and stable structure; that in the SW treatment was a loosely structured accumulation of large particles; and that in the BW treatment had a flocculent structure with strong plasticity that flowed easily with water. These three types of suspended particles experienced two stages of sedimentation: short rapid sedimentation followed by slow sedimentation. Grid clogging at the emitter’s water inlet caused emitter clogging. The total mass of sediment in laterals in the HW treatment was the largest, and the Dra was the smallest; the total mass of sediment in laterals in the BW treatment was the smallest, and the Dra was the largest. In the SW treatment, the values of these two indexes were between those in the HW and BW treatments. Single suspended particles, such as quartz sand (powder) or sodium bentonite (clay), had more difficulty forming stable clogging structures, so the Dra was relatively high. Coarse and fine particles were balanced in Yellow River sand; thus, the emitter was easily clogged, and the degree of clogging was the most serious. This study tried to provide a basis for the differences and formation mechanisms of emitter clogging and the anti-clogging strategies of emitters in drip irrigation systems in different reaches of the Yellow River.

Experimental Study on the Riverbed Coarsening Process and Changes in the Flow Structure and Resistance in the Gravel Riverbed Downstream of Dams

Following the construction of a reservoir, sediment is intercepted, which greatly reduces the sediment concentration in the discharged flow. This reduction causes riverbed scouring and flow structure adjustments downstream, thereby impacting the river habitat. This study used the generalized flume test with different bed sand compositions and discharge rates to simulate the scouring adjustment process of a sand pebble riverbed channel downstream of a reservoir. The results show that the bed sediment composition affects the water surface gradient, scour depth, turbulence intensity, and sand resistance directly after final scouring. Coarse-grained bed sediment demonstrated the greatest final turbulence intensity and sand resistance, while bed sediments with reduced coarseness exhibited a greater scouring degree; the resistance for sand grains of moderate coarseness showed the greatest change. Sand resistance was exponentially and positively correlated with the median grain size and the fractal dimension of bed sediment mass. The mass fractal dimension expression was suitable for the analysis of bed sand grain-size distribution; it contributed to the calculation of grain resistance with fewer hydraulic parameters. The relationship between the mass fractal dimension and the adjusted grain resistance was also established, which can aid the calculation of the resistance changes in sandy gravel-bed river reaches downstream of reservoirs, enabling the prediction of their effects on aquatic habitats.

The Oldoynio Lengai volcano, Tanzania: the essence of its recent eruptions

The article considers the nature of the volcanic fluxes that are traditionally interpreted as the only example of recent mantle-derived carbonatite lavas (carbonate magmas or melts) on the Earth. However, it turns out that this is not correct. These fluxes represent muddy soda masses with organics. Their source are masses of solutions and sediments of the Natron alkaline lake, that penetrate deep to the above-chamber space of the volcano along riftogenic faults, where they are heated and then erupt as fluxes, geysers, and ash masses. The eruption products in turn get to the lake again. At the recent stage of development, the Oldoynio Lengai volcano represents an epimagmatic phreatic hydrothermal recycling system.

Numerical Simulation of Imported Sediment in a Stilling Basin

Sediment buildup at the bottom of a stilling basin can result in premature drainage of spillway structures and can even lead to dam failure in severe cases. Such failures pose ecological and human safety hazards to downstream areas. To evaluate the sudden discharge and potential dam failure associated with sediment buildup, we developed a two-dimensional two-phase flow simulation model built on a particle-based force balance equation. We compared the flow patterns and energy dissipation effects in the stilling basin at different inlet flows (2, 3, 4.5, and 6.75 m2/s), and the subsequent bottom deposition was compared across different sand discharge mass flow rates (0.1, 0.2, and 0.3 kg/s). The results show that the turbulent energy increased with the increasing inlet unit width flow rate. When more vortices were generated and the flow velocity was reduced significantly, the energy dissipation was more effective. The sediment deposition at the bottom of the stilling basin gradually increased with the decrease of inlet unit width flow and the decrease of the sediment mass flow rate. Meanwhile, at a fixed inlet shape, the change in inlet unit width flow had little effect on the maximum sedimentation height at the bottom of the basin. In addition, the average deposition rate at the bottom of the stilling basin was positively correlated with the inlet sedimentation concentration, and the correlation coefficient could be as high as 0.97. In this two-phase flow method, the error of the simulated value over the theoretical value was less than 10%. This simulation of sediment deposition at the bottom of the stilling basin provides a practical reference for dam managers.

Equilibrium sediment transport by dilute turbidity currents: Comparison of competence‐based and capacity‐based models

AbstractEquilibrium sediment transport is the condition of zero net entrainment and deposition by sediment‐transporting flow (i.e. grade or regime). Here criteria for equilibrium sediment transport, or those used as proxies for equilibrium (for example, onset of erosion, onset of particle setting or suppression of turbulence) for dilute, suspended‐load‐dominated, turbidity currents, are tested against laboratory and natural data. The examined criteria are restricted to those describing flow over a bed of loose particulate material involving non‐cohesive sediment. Models include both monodisperse and polydisperse formulations that represent sediment non‐uniformity by using a single characteristic grain size or discretization of the grain‐size distribution, respectively. Analysis shows that a polydisperse‐type flux‐balance model, that equates erosional and depositional fluxes and where erosion is related to the power used to lift sediment mass from the bed (the ‘Flow‐Power Flux‐Balance’ model) provides predictions most consistent with observational data. Other equilibrium models tested, monodisperse or polydisperse, fail to predict realistic bed slopes and/or flow durations for concentrations, velocities and depths within limits for natural flows. Results of the Flow‐Power Flux‐Balance model are used to quantify sediment transport fields, equilibrium Shields numbers and slopes for turbidity currents of variable flow and particle properties.

Physical Disturbance by Bottom Trawling Suspends Particulate Matter and Alters Biogeochemical Processes on and Near the Seafloor

Bottom trawling is known to affect benthic faunal communities but its effects on sediment suspension and seabed biogeochemistry are less well described. In addition, few studies have been carried out in the Baltic Sea, despite decades of trawling in this unique brackish environment and the frequent occurrence of trawling in areas where hypoxia and low and variable salinity already act as ecosystem stressors. We measured the physical and biogeochemical impacts of an otter trawl on a muddy Baltic seabed. Multibeam bathymetry revealed a 36 m-wide trawl track, comprising parallel furrows and sediment piles caused by the trawl doors and shallower grooves from the groundgear, that displaced 1,000 m3 (500 t) sediment and suspended 9.5 t sediment per km of track. The trawl doors had less effect than the rest of the gear in terms of total sediment mass but per m2 the doors had 5× the displacement and 2× the suspension effect, due to their greater penetration and hydrodynamic drag. The suspended sediment spread &amp;gt;1 km away over the following 3–4 days, creating a 5–10 m thick layer of turbid bottom water. Turbidity reached 4.3 NTU (7 mgDW L–1), 550 m from the track, 20 h post-trawling. Particulate Al, Ti, Fe, P, and Mn were correlated with the spatio-temporal pattern of suspension. There was a pulse of dissolved N, P, and Mn to a height of 10 m above the seabed within a few hundred meters of the track, 2 h post-trawling. Dissolved methane concentrations were elevated in the water for at least 20 h. Sediment biogeochemistry in the door track was still perturbed after 48 h, with a decreased oxygen penetration depth and nutrient and oxygen fluxes across the sediment-water interface. These results clearly show the physical effects of bottom trawling, both on seabed topography (on the scale of km and years) and on sediment and particle suspension (on the scale of km and days-weeks). Alterations to biogeochemical processes suggest that, where bottom trawling is frequent, sediment biogeochemistry may not have time to recover between disturbance events and elevated turbidity may persist, even outside the trawled area.

A New Framework for Modelling Fine Sediment Transport in Rivers Includes Flocculation to Inform Reservoir Management in Wildfire Impacted Watersheds

Fine-grained cohesive sediment is the primary vector for nutrient and contaminant redistribution through aquatic systems and is a critical indicator of land disturbance. A critical limitation of most existing sediment transport models is that they assume that the transport characteristics of fine sediment can be described using the same approaches that are used for coarse-grained non-cohesive sediment, thereby ignoring the tendency of fine sediment to flocculate. Here, a modelling framework to simulate flow and fine sediment transport in the Crowsnest River, the Castle River, the Oldman River and the Oldman Reservoir after the 2003 Lost Creek wildfire in Alberta, Canada was developed and validated. It is the first to include explicit description of fine sediment deposition/erosion processes as a function of bed shear stress and the flocculation process. This framework integrates four existing numerical models: MOBED, RIVFLOC, RMA2 and RMA4 using river geometry, flow, fine suspended sediment characteristics and bathymetry data. Sediment concentration and particle size distributions computed by RIVFLOC were used as the upstream boundary condition for the reservoir dispersion model RMA4. The predicted particle size distributions and mass of fine river sediment deposited within various sections of the reservoir indicate that most of the fine sediment generated by the upstream disturbance deposits in the reservoir. Deposition patterns of sediment from wildfire-impacted landscapes were different than those from unburned landscapes because of differences in settling behaviour. These differences may lead to zones of relatively increased internal loading of phosphorus to reservoir water columns, thereby increasing the potential for algae proliferation. In light of the growing threats to water resources globally from wildfire, the generic framework described herein can be used to model propagation of fine river sediment and associated nutrients or contaminants to reservoirs under different flow conditions and land use scenarios. The framework is thereby a valuable tool to support decision making for water resources management and catchment planning.

From Patagonia to Río de la Plata: Multistep long‐distance littoral transport of Andean volcaniclastic sand along the Argentine passive margin

AbstractLarge sediment masses are transferred over many hundreds of kilometres along the coast of passive continental margins worldwide. The relevance of such a phenomenon for source‐to‐sink studies, environmental issues, and coastal management remains largely unperceived. This study traces the paths of volcaniclastic sand along ca 2170 km of the Argentine coast and documents a 760 km long cell of littoral transport extending from the formerly larger Río Colorado delta to the edge of the Río de la Plata mouth. During deglaciation stages and humid periods of the Pleistocene, a much greater sediment volume than today was transferred by the Desaguadero and Colorado rivers from the highest‐relief tract of the Andean Cordillera to the Atlantic Ocean. Amphibole‐rich sand originally supplied by the Río Desaguadero is being recycled today from Pampean lowlands to feed the beaches along Río de la Plata southern shores, whereas pure quartzose sand of Río Paraná is found only adjacent to its prograding delta. Augite‐rich sand supplied by the Río Colorado is dominant along the coast of the Buenos Aires Province, where it mixes locally with coarser‐grained quartz‐rich detritus recycled in the urbanized Mar del Plata area. Hypersthene‐rich sand of the Río Negro is dispersed both north and south of the mouth, where heavy‐mineral‐rich lag deposits are formed in areas of accelerated erosion and retreating sea cliffs. Changes of mineralogical signatures during long‐distance littoral transport are largely ascribed to local supply from coastal erosion or hydrodynamic effects rather than to selective breakdown of labile grains. Whereas the relative abundance of amphibole and pyroxene is largely independent of transport distance, olivine is depleted both in the northern part of the Colorado littoral cell and south of the Río Negro mouth, which is chiefly ascribed to dilution by recycling of Neogene sediments that have undergone early intrastratal dissolution rather than to mechanical loss.

Giant slope scars and mass transport deposits across the Rhodes Basin, eastern Mediterranean: Depositional and tectonic processes

High-resolution multichannel seismic reflection profiles and multibeam mosaic maps of the seafloor are used to document the presence of two prominent regions representing major sediment failure(s) and the subsequent gravity-driven mass transport across the southwestern continental margin of Anatolia. These regions are characterized by very sugged morphology (referred to as Scars 1 and 2), where the upper slope regions include several concave, interconnected steep seafloor escarpments marked by semi-circular indentations that link with one another by cusp-like features creating a sharp and very narrow curvilinear zone. The slope face across the rugged region there are numerous sharply irregular pinnacles/protrusions on the seafloor, consisting of exposed older bedrock successions. Scars 1 and 2 occupy seafloor areas of 1947 km2 and 1350 km2, solid volumes of 214–257 km3 and 92–111 km3, and masses of 467–681 Gt and 245–294 Gt, respectively, with a total solid volume of 307–368 km3 and a mass of 812–975 Gt. Mass transport deposits are identified at various stratigraphic levels across the Rhodes Basin characterized by chaotic seismic reflector configurations with zones of contorted and convoluted reflector geometries. The base of this facies is characterized by erosional down-cutting. The thickest and the regionally most extensive such deposits are found at the base of Unit 1, immediately above the upper bounding surface of the Messinian evaporites (the Top Erosional Surface or the former M-reflector). The lower mass transport deposit (L–MTD) is calculated to have a volume 205–171 km3, or a solid mass of 543–452 Gt, assuming that porosities of 40–50% and average grain density of 2.67 t m−3. Comparisons between the total mass of the L–MTD and the estimated masses of sediments mobilized across Scars 1 and 2 (812–975 Gt) indicate that there is ~360–432 Gt deficit in the calculated mass of the L–MTD. The missing sediments represent 17.5–21.0% of the total mass contained within Unit 1 across the present-day Rhodes Basin. This mismatch is remarkably large: it may arise from the uncertainties involved in the estimations of the masses of sediments contained in Scars 1 and 2; however, it is also possible that some of the gravity driven mass transports transitioned into turbidity currents, thus travelled great distances across the Rhodes Basin, and that some of these turbidity currents crossed the basin longitudinally, and exited it at its southwestern deeper regions (i.e., the present-day Strabo Trench). This is particularly plausible because the physiography of the Rhodes Basin was dramatically different during the early Pliocene and the southern and southwestern portions of the basin provided a possible exit route.

Rapid determination of total metals: synergic effect of ultrasound energy and ionic liquids on the digestion of sediment samples

PurposeThe aim of this study was to develop a new and rapid sample digestion procedure for metal extraction using ultrasonic energy together with a combination of an ionic liquid and mineral acids as extractants.MethodsA fixed mass of sediment (about 0.50 g) was extracted with a combination of low volumes of NaHCO3, HCl, HNO3, HF and the ionic liquid Bmim[BF4]. Afterwards, the mixture was sonicated for 20 min. After neutralizing the hydrofluoric acid excess, the extracts were filtered and measured by ICP OES where Cd, Cr, Cu, Ni, Pb and Zn were determined.ResultsThe recoveries in certified reference materials ranged from 92 to 102% for LGC-6137, from 88 to 98% for IAEA SL-1 and from 81 to 98% for MURST-ISS-A1, with a good precision (relative standard deviation (RSD) < 10.0% for all the certified reference materials). The new digestion procedure was successfully applied to the determination of metals in estuarine sediment samples, with a satisfactory precision (RSD < 9.5%). The results showed no significant statistical differences compared to those obtained by the conventional digestion procedure (with an α-error of 0.05).ConclusionThis approach has led to satisfactory results in the determination of the total metal concentrations for most of the elements studied using shorter analysis times than the conventional procedure, and small volumes of hydrofluoric acid. The new pretreatment method made it possible to satisfactorily assess the total metal concentrations in estuarine sediments.

Source‐to‐sink response to high‐amplitude lake level rise driven by orbital‐scale climate change: An example from the Pleistocene Lake Malawi (Nyasa) Rift, East Africa

AbstractSedimentary systems respond to environmental forcings in dissimilar ways over different timescales. The Lake Malawi (Nyasa) Rift is an ideal natural laboratory for evaluating the overall functioning of lacustrine source‐to‐sink systems on orbital or younger scales. These closed sedimentary systems exhibited high spatiotemporal climate variability, and their responses to two late Pleistocene lake‐level stillstands are evaluated. The coarse‐grained deposits documented a dramatic transgression from 350 to 200 m below present lake‐level (BPLL) developed during an important climate transition in tropical Africa. Based on an integrated analysis of a digital elevation model and high‐resolution single/multi‐channel seismic profiles, catchment geomorphology has been linked with sediment delivery in the sink area. The coarse‐grained deposition of each source‐to‐sink system is quantified through a sediment mass calculation. A modified empirically‐derived ‘BQART’ predictor with a bedload equation to assess the sediment discharge is employed based on a Monte Carlo simulation, considering temperature lapse rate and topographic effects. The river discharges are estimated by specific empirical relationships that associate catchment area to various climate systems, developed using a global modern river database. The results show that the total sediment discharge increases from 7.53 to 9.50 Mt year−1; likewise, the preserved coarse‐grained deposits also record a significant increase in deposition rate from 350 to 200 m BPLL stage, indicating that the short length‐scale source‐to‐sink systems are sensitive to the high‐amplitude lake transgression developed from the climate shift. The volume of upstream buffered deposits may decrease within the progressively wetter climate, while the buffering degree was substantially influenced by the pre‐existing landforms. Moreover, the substantial deep‐water mud dispersal is not well‐developed, despite the relatively higher lake‐level and slightly wetter climate. This quantitative source‐to‐sink analysis with the modified sediment predictor yields preliminary constraints for system functioning in response to high‐amplitude climate change in a closed sedimentary system.

Reply to comments on the paper “Evaluating and modelling splash detachment capacity based on laboratory experiments” by P.I.A. Kinnell (2019). Catena 183, 104189

In this study, we used a new approach to measure and determine the splash detachment based on theories of soil erosion, the large number of articles published on the topic and simulated rainfall experiments. It is a necessity to use and improve new methods to accurately evaluate and quantify the processes of soil erosion. In this experiment, a soil pan with three areas, which consisted of a test area, complementary border area and a splash collector for slots, was used to obtain the ability of soil to undergo splash detachment. In this study, the soil surface was uniform and composed of a smooth slope and depth of thin layer flow that was < 0.43 mm. When raindrop splash occurs on the soil surface covered by a thin layer flow, all the soil materials detached by raindrop splash can only depart the soil surface and penetrate through the thin layer flow into the air and then fall to the soil surface. Splashed soil particles were collected and measured in our experimental setup to represent the amount of detached soil material that instantaneously fell on the test area. This material was quantified in mass per unit area per unit time, which is equal to the sample sediment mass divided by the slot area and the sample time. Thus, it is an expression of the raindrop splash detachment capacity observed in this study. Soil particles occupy all the spaces next to each other, and there is no space for the splashed soil material to move parallel to the soil surface within the soil mass. They may only depart from the soil mass itself. The thin layer flow has a very small depth. The detached soil materials cannot obtain enough space in the water depth to enter and to be maintained within the water depth. They easily penetrate the thin layer flow and enter the air. Once the splashed materials have entered the air, they can quantitatively be observed to represent the splash detachment using the soil pan with three areas in this study. Consequently, the splashed soil materials that were collected using this facility were all soil materials that were detached by the splashing of raindrops during the experiments.

Reply to comment on, “Sediment budget and morphological change in the Red River Delta under increasing human interferences” by N.D. Ve, D. Fan, B.V. Vuong and T.D. Lan [Marine Geology 431 (2021), 106,379

Anh (2021) asserts that the sediment budget model by Ve et al. (2021) of the subaqueous Red River Delta (RRD) is inaccurate because of some fundamental flaws in the DEM analysis and budget estimation. In fact, bathymetric data from the two earliest charts have been validated with data from a survey carried out over a short time span (1927–1930) and a linear semi-variogram model used to do the kriging interpolation. Different grid cell sizes have a negligible effect on the DEM analysis, and the effect of relative sea-level rise has been ruled out by normalization of bathymetrical data from sequential charts to a common tidal datum. Furthermore, the estimation of the amount of deposited sediment on tidal flats is correct, although a typo of sediment volume unfortunately yielded a wrong value. We can thus confirm that the data in the sediment budget model of Ve et al. (2021) are reliable.The sediment budget model can be improved by full consideration of sediment from source to sink processes as suggested by Anh (2021). We therefore refine the model by considering river bedload and sand mining in the RRD in the sediment input item, and separate the subtidal RRD into three subzones to calculate their average depositional/erosional sediment volume and mass. In the revisited model, a total of 54.7 Mt./yr is inferred to be deposited in the subaqueous RRD from the intertidal flats to the delta-front slope, of which 75.3% and 24.7% are conceivably sourced by the Red River and eroded from the prodelta and offshore shelf, respectively. However, the controlling mechanism of secular erosion at the prodelta and offshore shelf is so far not well known, and this will need to be investigated in the future.

Revisited sediment budget with latest bathymetric data in the highly altered Yangtze (Changjiang) Estuary

Most river-deltas of the world have been extremely altered by anthropic activities, where a regime shift from net accretion into net erosion may have occurred. In this study, subtidal morphodynamic variations in the Yangtze Estuary (YE) are elaborately analyzed for their causalities using high resolution DEM data from bathymetric surveys conducted every two years from 2007 to 2019; sediment budgetary balance in the estuary has been updated accordingly with mean annual depositional/erosional sediment amounts. The results show that subtidal channel erosion has occurred almost over the whole YE with a mean annual erosional rate of −5.59 cm/yr during the study period. Peak erosion occurred both in the South Branch and the delta front with mean annual erosional rates of −12.64 cm/yr and −8.11 cm/yr, respectively. The erosion lessened in the middle estuary where sandy shoals prevail, and a net accretive rate of 3.13 cm/yr was solely measured at the Chongming shoal. Negative correlation between estuarine erosional volume and riverine sediment discharge demonstrates the great impact of upstream hydro-engineering projects on estuarine morphodynamic change, but large-scale estuarine engineering projects also exert remarkable influence on local morphodynamics, evidenced by the presence of deep erosional belts near the projects. Annually eroded sediment amounts were estimated as 166 Mt/yr and 206 Mt/yr in the distributary channels and the delta front during the period 2007–2019, and the former was almost offset by recent sand mining amount of 143 Mt/yr from the distributary channels for land reclamation. Moreover, contemporary eroded sediment mass and sand mining amount from the tidal river reach between Datong and Xuliujing were reckoned as 77 Mt/yr and 44 Mt/yr, respectively. Our analysis further show that recently 124 Mt/yr and 153 Mt/yr of sediment discharge into the tidal river reach at Datong station and the YE at Xuliujing station account for merely 27.5% and 37.7% of their corresponding values before the 1990s, respectively. Annual sediment amount bypassing the estuary into the open sea has decreased by 37.8% from pre-1990s 370 Mt/yr to recent 140 Mt/yr, leading to recently severe erosion in the delta front. It is therefore highlighted that the estuarine system in response to natural and anthropogenic pressures is very dynamic, and the impacts of various engineering projects in the source-to-sink system should be fully taken into consideration when predicting its morphodynamic response in the estuary.

Crude oil compatibility testing using pumping and filtration methods

According to the National Bank of Poland, by the end of 2019, oil imports to Poland amounted to 26.3 million tonnes of crude oil, where the main volume came from Russia. The need to ensure greater energy security enforces the diversification of crude oil supplies, thus the largest domestic refineries are increasing the share of supplies from different sources each year. This entails the need for continuous information on the profitability of processing new types of crude oil and potential problems resulting in increased cost. Quality control of the crude oil offered on the market helps minimize the risk of purchasing incompatible oil types by ensuring that the proposed shipment meets the relevant quality requirements. Of particular importance is the fact that such tests should be performed prior to the decision to purchase a particular crude oil and introduce it to the refinery’s installation. It often happens, however, that detailed tests are performed only after the purchase. It is important to note that testing the physicochemical properties and determining the yield of individual fractions alone is not sufficient. Precipitation of sediments in the logistic chain of crude oil is a significant problem both in pipeline installations, storage depots, and refinery installations, where crude oil containing dispersed sediments is processed. In the previous stage of work, an effective filtration method was developed to determine the compatibility of crude oils and their mixtures. Now, attention was focused on developing a new method that allowed for a faster compatibility measurement capability along with reusing samples for another measurement. The developed new method of pump compatibility testing was tested for two crude oils from different supply directions. The measurements were performed for crude oils and their mixtures at 150°C under 25 bar pressure. Compatibility of crude oils with the filtration method was used for comparison, where based on the mass of sediment separated on special filters, the allowable concentrations where hydrocarbon mixtures were compatible were determined.