Static Depth Research Articles

Enhancing the field-of-view of spectral-scanning FMCW LiDAR by multipass configuration with an echelle grating.

We present a spectral-scanning frequency-modulated continuous wave (FMCW) 3D imaging system capable of producing high-resolution depth maps with an extended field of view (FOV). By employing a multipass configuration with an echelle grating, the system achieves an FOV of 5.5° along the grating axis. The resulting depth maps have a resolution of 70 × 40 pixels, with a depth resolution of 5.1 mm. The system employs an echelle grating for beam steering and leverages the multipass configuration for angular FOV magnification. Quantitative depth measurements and 3D imaging results of a static 3D-printed depth variation target are demonstrated. The proposed approach offers a promising solution for enhancing the FOV of spectral-scanning FMCW LiDAR systems within a limited wavelength-swept range, thereby reducing system complexity and cost, paving the way for improved 3D imaging applications.

Splash lubrication for an orthogonal face gear using numerical investigation integrating image processing

With practical physical immersion depth as their joint, the relations between the oil distribution characteristics and the associated no-load power losses for splash-lubricated orthogonal face gears are explored and quantified in this paper. Firstly, a theoretical analytical model is proposed to estimate the churning losses of an isolated face gear considering all the preceding parameters, along with a numerical model of a face gear stirring oil developed based on the sliding mesh strategy. Then the accuracy and correctness of the computational fluid dynamics method are verified with experiments in terms of oil flow behavior and no-load losses. Finally, the physical immersion depth is determined by leveraging the image processing technique and substituted into the theoretical model replacing the static depth with an improvement of prediction accuracy. Last but not least, this practical immersion depth acts as a link to facilitate the communication between the oil distributions and the no-load power losses within the gearboxes.

Dynamics of collapse of free-surface bubbles: effects of gravity and viscosity

The rupture of the thin film at the top of a bubble at a liquid–gas interface leads to an axisymmetric collapse of the bubble cavity. We present scaling laws for such a cavity collapse, established from experiments conducted with bubbles spanning a wide range of Bond ( ${10^{-3}< Bo\leq 1}$ ) and Ohnesorge numbers ( ${10^{-3}< Oh<10^{-1}}$ ), defined with the bubble radius $R$ . The cavity collapse is a capillary-driven process, with a dependency on viscosity and gravity, affecting respectively, precursory capillary waves on the cavity boundary and the static bubble shape. The collapse is characterised by the normal interface velocity ( $U_n$ ) and by the tangential wave propagation velocity of the kink ( $U_t$ ), defined by the intersection of the concave cavity boundary formed after the rupture of the thin film with the convex boundary of the bubble cavity. During the collapse, $U_t$ remains constant and is shown to be $U_t=4.5U_c{\mathcal {W}}_R$ , where $U_c$ is the capillary velocity and ${\mathcal {W}}_R(Oh,Bo)={(1-\sqrt {Oh {\mathscr {L}}} )^{-1/2}}$ is the wave resistance factor due to the precursory capillary waves, with $\mathscr {L}(Bo)$ being the path correction of the kink motion. The movement of the kink in the normal direction is part of the inward shrinkage of the whole cavity due to the sudden reduction of gas pressure inside the bubble cavity after the thin film rupture. This normal velocity is shown to scale as $U_c$ in the equatorial plane, while at the bottom of the cavity $\bar {U}_{nb}=U_c(Z_c/R)({\mathcal {W}_R}/ {\mathscr {L}})$ , where $Z_c(Bo)$ is the static cavity depth. The filling rate of the cavity, which remains a constant throughout the collapse, is shown to be entirely determined by the shrinking velocity and scales as ${Q_T\simeq 2{\rm \pi} R Z_c U_c}$ . From $Q_T$ we recover the jet velocity scaling, thereby relating the cavity collapse with the jet velocity scaling.

An inter-comparison of approaches and frameworks to quantify irrigation from satellite data

Abstract. This study provides the first inter-comparison of different state-of-the-art approaches and frameworks that share a commonality in their utilization of satellite remote-sensing data to quantify irrigation at a regional scale. The compared approaches vary in their reliance on either soil moisture or evapotranspiration data or their joint utilization of both. The two compared frameworks either extract irrigation information from residuals between satellite observations and rainfed hydrological models in a baseline framework or use soil water balance modeling in a soil-moisture-based inversion framework. The inter-comparison is conducted over the lower Ebro catchment in Spain where observed irrigation amounts are available for benchmarking. Our results showed that within the baseline framework, the joint approach using both soil moisture and evapotranspiration (ET) remote-sensing data only differed by +37 mm from the irrigation benchmark (922 mm) during the main irrigation season over 2 years and by +47 and −208 mm for approaches relying solely on soil moisture and ET, respectively. A comparison of the different frameworks showed that the main advantage of the more complex baseline framework was the consistency between soil moisture and ET components within the hydrological model, which made it unlikely that either one ended up representing all irrigation water use. However, the simplicity of the soil-moisture-based inversion framework, coupled with its direct conversion of soil moisture changes into actual water volumes, effectively addresses the key challenges inherent in the baseline framework, which are associated with uncertainties related to an unknown remote-sensing observation depth and the static depth of the soil layers in a conceptual model. The performance of the baseline framework came closest to the irrigation benchmark and was able to account for the precipitation input, which resulted in more plausible temporal distributions of irrigation than what was expected from the benchmark observations.

Spatial distribution patterns of striped venus clam (Chamelea gallina, L. 1758) natural beds in the Gulf of Cádiz (SW Spain): Influence of environmental variables and management considerations

Spatial distribution of characteristic population parameters (density, biomass and mean size) of Chamelea gallina were analyzed from systematic survey data applying a geostatistical approach in the Gulf of Cádiz (SW Spain). The influence of static (depth and distance to inland outflows), dynamic (sediment and water column features) environmental variables on density, biomass and mean size was also investigated. The global estimations of kriged density mean was 8.30 ind m−2, biomass mean was 23.78 g m−2, and mean size was 18.71 mm, with the species heterogeneously distributed along the whole sandy subtidal strip of the coast of Huelva. The resulting kriged map shows the location and extension of the patches (5 NM range) in the study area; where the highest density and biomass hot-spots were observed near the river mouths, except for the Guadiana River. This species was present from 3 to 16 m, but preferred the depth window between 6-8 m, having a density and biomass peak at approximately 7 m depth. A negative and significant correlation was found between density/biomass and the coefficient of variation of mean size suggesting a density-dependent process. The most influential factors on density and biomass were depth, sediment characteristics (grain size and percentage of organic content), distance from river mouths and waste water treatment plants, and sea bottom temperature. This study, in addition to reporting on the current status of these natural beds and the influence of dynamic and static environmental variables on their distribution, proposes an additional approach to estimating several biological parameters in C. gallina that could be valuable for the spatial management of this commercial resource and highlight the role of marine protected areas.

Accuracy evaluation of scour depth equations under the submerged vertical jet

Abstract Scouring of sediment materials under submerged vertical jets is shown at grade-control structures, downstream of weirs, and submerged vertical water jets have several uses, including seabed sediment removal and dredging in ocean engineering. Numerous studies have been conducted to demonstrate the scour process and the variation of scour profile utilizing various influencing parameters. Many researchers developed equations for predicting the scour hole characteristics. Previous studies identified two types of scour hole depth configurations: static and dynamic scour depth and the variation of scour hole variations differs for long- and short-impinging jet height conditions. In this study, extensive data on non-dimensional static and dynamic scour depth under short- and long-impinging jets acquired from prior literature, and the previously proposed equations of static and dynamic scour depth were analyzed using graphical and statistical analysis. The findings demonstrated that the relationships proposed by Aderibigbe and Rajaratnam (1996) for long-impinging jets and Amin et al. (2021) for short-impinging jets predict the static scour depth better than the other equations. The proposed equations for dynamic scour depth under long- and short-impinging jets are highly biased and inaccurate.

Development of an analytical model to predict the churning power losses of an orthogonal face gear

As one of the basic energy dissipations for one orthogonal face gear running partially submerged in an oil bath, there is no open literature concerned on the churning power losses of the face gear. This paper proposed a series of formulas to predict the churning losses for one orthogonal face gear running partially submerged in an oil bath. The analytical model of churning drag forces is based on fluid mechanics and boundary layer theory which enables quantitatively calculating the influences of the rotating speed, fluid attributes, and gear geometric construction with the minimum effort. Then, an ad hoc test bench was set up to carry out the specific splash lubrication tests for single face gear at different rotating speeds and initial immersion depth. Finally, considering both the churning and windage effects, a physical-based model adopting the real-time immersion depth instead of the static immersion depth is developed to calculate the total load-independent losses of a splash lubricated face gear. From this, the theoretical results are compared well with sets of directly measured experimental findings. Meanwhile, the model is also exploited to quantitate the contributions of each part in the total load-independent losses for one face gear under splash lubrication condition.

Identifying cortical areas that underlie the transformation from 2D retinal to 3D head-centric motion signals

Accurate motion perception requires that the visual system integrate the 2D retinal motion signals received by the two eyes into a single representation of 3D motion. However, most experimental paradigms present the same stimulus to the two eyes, signaling motion limited to a 2D fronto-parallel plane. Such paradigms are unable to dissociate the representation of 3D head-centric motion signals (i.e., 3D object motion relative to the observer) from the associated 2D retinal motion signals. Here, we used stereoscopic displays to present separate motion signals to the two eyes and examined their representation in visual cortex using fMRI. Specifically, we presented random-dot motion stimuli that specified various 3D head-centric motion directions. We also presented control stimuli, which matched the motion energy of the retinal signals, but were inconsistent with any 3D motion direction. We decoded motion direction from BOLD activity using a probabilistic decoding algorithm. We found that 3D motion direction signals can be reliably decoded in three major clusters in the human visual system. Critically, in early visual cortex (V1-V3), we found no significant difference in decoding performance between stimuli specifying 3D motion directions and the control stimuli, suggesting that these areas represent the 2D retinal motion signals, rather than 3D head-centric motion itself. In voxels in and surrounding hMT and IPS0 however, decoding performance was consistently superior for stimuli that specified 3D motion directions compared to control stimuli. Our results reveal the parts of the visual processing hierarchy that are critical for the transformation of retinal into 3D head-centric motion signals and suggest a role for IPS0 in their representation, in addition to its sensitivity to 3D object structure and static depth.

ИССЛЕДОВАНИЕ ВОДОНОСНЫХ ГОРИЗОНТОВ НА ПРИМЕРЕ ОБЛАСТИ ЕЛ-ОВЕЙНАТ, ЕГИПЕТ

The analysis of the geological structure of aquifer layers made it possible to solve two important tasks: (1) determination of the aquifer system and groundwater flow, (2) assessment of the well efficiency of existing productive wells. The resulting solution was based on three-dimensional modeling using borehole geophysical data and the involvement of comprehensive information on the development of water resources. The result was new knowledge about the studied aquifer system in its geophysical, geological and field context. It consists in determining: the static water depth and the direction of the main flow, the structure of the aquifer with the distribution of aquifer layers and aquitard layers, basement rocks, as well as the well efficiency and the aquifer loss coefficients. These measures make it possible to increase the well efficiency and managing the process of pumping water from existing wells, as well as to optimize the drilling of new wells in the area under consideration.

A CNN for Range and Seabed Estimation on Normalized and Extracted Time-Series Impulses

Deep learning techniques have the potential to address real-time source localization and seabed characterization from passive ocean acoustic signals. The challenge grows when considering single-sensor cases that lack absolute travel time with no known source or environmental parameters. To address this, convolutional neural networks (CNNs) are trained to predict the source–receiver range and the seabed type on extracted and normalized 1-s pressure time series from explosive charges measured during the 2017 Seabed Characterization Experiment. To investigate the impact of ocean variability, two training data sets containing different sets of water sound-speed profiles (SSPs) are used. CNNs trained on the first synthetic data set, which contains a static ocean depth but significant variability in water SSPs, predict seabed class more accurately than the second data set from the measured data. Conversely, CNNs trained on the second synthetic data set, which contains fewer SSPs (similar to those measured during the experiment) and multiple ocean depths, predict the source–receiver range more accurately than the first data set from the measured data. The CNNs, with a degree of uncertainty, predict the seabed type and the source range when trained on synthetic data that have been stripped of source–receiver information, such as arrival time and amplitude. The CNNs trained to only predict the seabed type also make more accurate predictions on the seabed type when compared to those for multiple prediction types. This study highlights the importance of accounting for ocean variability and prediction uncertainties in training deep learning algorithms for marine applications.

Comparison of Machine Learning-Based Snow Depth Estimates and Development of a New Operational Retrieval Algorithm over China

Snow depth estimation with passive microwave (PM) remote sensing is challenged by spatial variations in the Earth’s surface, e.g., snow metamorphism, land cover types, and topography. Thus, traditional static snow depth retrieval algorithms cannot capture snow thickness well. In this study, we present a new operational retrieval algorithm, hereafter referred to as the pixel-based method (0.25° × 0.25° grid-level), to provide more accurate and nearly real-time snow depth estimates. First, the reference snow depth was retrieved using a previously proposed model in which a microwave snow emission model was coupled with a machine learning (ML) approach. In this process, an effective grain size (effGS) value was optimized by utilizing the snow microwave emission model, and then the nonlinear relationship between snow depth and multiple predictive variables, e.g., effGS, longitude, elevation, and brightness temperature (Tb) gradients, was established with the ML technique to retrieve reference snow depth data. To select a robust and well-performing ML approach, we compared the performance of widely used support vector regression (SVR), artificial neural network (ANN) and random forest (RF) algorithms over China. The results show that the three ML models performed similarly in snow depth estimation, which was attributed to the inclusion of effGS in the training samples. In this study, the RF model was used to retrieve the snow depth reference dataset due to its slightly stronger robustness according to our comparison of results. Second, the pixel-based algorithm was built based on the retrieved reference snow depth dataset and satellite Tb observations (18.7 GHz and 36.5 GHz) from Advanced Microwave Scanning Radiometer 2 (AMSR2) during the 2012–2020 period. For the pixel-based algorithm, the fitting coefficients were achieved dynamically pixel by pixel, making it superior to the traditional static methods. Third, the built pixel-based algorithm was verified using ground-based observations and was compared to the AMSR2, GlobSnow-v3.0, and ERA5-land products during the 2012–2020 period. The pixel-based algorithm exhibited an overall unbiased root mean square error (unRMSE) and R2 of 5.8 cm and 0.65, respectively, outperforming GlobSnow-v3.0, with unRMSE and R2 values of 9.2 cm and 0.22, AMSR2, with unRMSE and R2 values of 18.5 cm and 0.13, and ERA5-land, with unRMSE and R2 values of 10.5 cm and 0.33, respectively. However, the pixel-based algorithm estimates were still challenged by the complex terrain, e.g., the unRMSE was up to 17.4 cm near the Tien Shan Mountains. The proposed pixel-based algorithm in this study is a simple and operational method that can retrieve accurate snow depths based solely on spaceborne PM data in comparatively flat areas.

Animal behavior is central in shaping the realized diel light niche.

Animal behavior in space and time is structured by the perceived day/night cycle. However, this is modified by the animals’ own movement within its habitat, creating a realized diel light niche (RDLN). To understand the RDLN, we investigated the light as experienced by zooplankton undergoing synchronized diel vertical migration (DVM) in an Arctic fjord around the spring equinox. We reveal a highly dampened light cycle with diel changes being about two orders of magnitude smaller compared to the surface or a static depth. The RDLN is further characterized by unique wavelength-specific irradiance cycles. We discuss the relevance of RDLNs for animal adaptations and interactions, as well as implications for circadian clock entrainment in the wild and laboratory.

Minimally invasive temporalis tendon transposition and upper lid lipofilling for immediate and secondary facial reanimation in patients treated for malignant tumors of the parotid gland

Treatment for facial nerve-invading parotid malignancies usually results in complete facial palsy. The authors present a novel technique to treat facial palsy following radical parotid surgery and retrospectively evaluate results in terms of soft tissue symmetry at rest and during smiling and eyelid closure using the eFACE system.9 patients with facial palsy following parotid malignancies resection or undergoing parotidectomy with planned facial nerve resection for tumor invasion were treated with the association of mini-invasive temporalis flap rotation and upper lid lipofilling to restore symmetry of the middle facial third at rest and during smiling and eyelid closure. The technique was employed during the same surgical session as the tumor removal or for secondary facial reanimation.Systematic eFACE evaluation demonstrated significant improvement in static nasolabial fold depth orientation and oral commissure position, palpebral fissure narrowing during eye closure, and oral commissure movement and nasolabial fold depth and orientation with smile (p respectively .008, .011, 0.008, 0.035, 0.011, 0.008, and 0.011, Wilcoxon's test). Furthermore, all patients described subjective improvement of corneal discomfort.The presented technique appears promising in treating facial palsy in oncological patients, representing a potential alternative to other more complex reconstructive techniques.

Monocular Perception of Equidistance: The Effects of Viewing Experience and Motion-generated Information.

Using static depth information, normal observers monocularly perceived equidistance with high accuracy. With dynamic depth information and/or monocular viewing experience, they perceived with high precision. Therefore, monocular patients, who were adapted to monocular viewing, should be able to perceive equidistance and perform related tasks. This study investigated whether normal observers could accurately and precisely perceive equidistance with one eye, in different viewing environments, with various optical information and monocular viewing experience. Sixteen normally sighted observers monocularly perceived the distance (5 to 30 m) between a target and the self and replicated it either in some hallways that contained ample static monocular depth information but had a limited field of view or on a lawn that contained less depth information but had a large field of view. Participants remained stationary or walked 5 m before performing the task, as a manipulation of the availability of dynamic depth information. Eight observers wore eye patches for 3 hours before the experiment and gained monocular viewing experience, whereas the others did not. Both accuracy and precision were measured. As long as static monocular depth information was available, equidistance perception was effectively accurate, despite minute underestimation. Perception precision was improved by prior monocular walking and/or experience with monocularity. Accuracy and precision were not affected by the viewing environments. Using static and dynamic monocular depth information and/or with monocular experience, normal observers judged equidistance with reliable accuracy and precision. This implied that patients with monocular vision, who are better adapted than participants of this study, should also be able to perceive equidistance and perform distance-dependent tasks in natural viewing environments.

GROUNDWATER EXPLORATION USING RESISTIVITY AND FLOWNET DATA AT THE EASTERN PART OF ILORIN, SOUTHWESTERN NIGERIA

Flownets, geo-electric layers construction and groundwater exploration analysis was investigated in the eastern and Western parts of Ilorin of Southwestern Nigeria. Apata-Yakuba, Eleko-yangan, Tepatan, Oke-Andi at the Eastern part and Akamo, Idi-Araba in the Western part of Ilorin were surveyed to depict the exact locations for potential future groundwater exploration. A preliminary step to collect lithologs of wells from the records of Nigeria Hydrological Services Agency used 35 water samples taken from hand dug wells and boreholes. Static water levels, total depth and coordinates of hand dug wells were measured using tape and GPS respectively. The Static water level (below ground surface and above sea level) values and their coordinates were processed using IPWIN resist software to generate the water level locations on topographical contour maps and the groundwater flow net of the study area. Result reflects the presence of crystalline rocks consisting of migmatite gneiss, granite gneiss, quartzite and granite. Analysis and interpretation of flownet shows ascending equipotential lines at the Eastern part indicating an easy groundwater movement, and divergent equipotential lines at the Western part indicating difficulty in water movement in the study area. The static water levels values together with the corresponding coordinates were superimposed on the geological map of the study area. This research reveals the water table is very close to ground surface in Oyun, Oke-Andi resulting into digging of shallow wells by the dwellers of the area. Water table is also far away from the surface in places Tepatan, Apata-Yakuba among others

Assessment of silica content in groundwater of Peninsular Indian region using statistical techniques

The groundwater resources from open dug wells are the ultimate and inevitable drinking water source in Chennai municipality. These are of shallow depth of 8 to 10m with a static water depth range of 30 to 75 m. This study's objective was to assess silica (in the form of Silicon Dioxide, SiO2) in groundwater and to establish their baseline concentration. Twelve wells were monitored in the study area, in some parameters, namely: Chloride (Cl-), Total Dissolved Solids (TDS), pH, Electrical Conductivity (EC), and SiO2. We examined the existing relationship between silica and other measured water quality parameters (Cl-, pH, TDS, and EC) using Spearman correlation matrix analysis in SPSS software and Normalized Difference Dispersal Index (NDDI) in Simplex Numerix software that was applied to identify the hotspots of SiO2. The water pH ranges from 8.09 to 8.37 (slightly alkaline) with an appreciable amount of TDS (730.50 to 1294.50 ppm). The groundwater also contains abundant silica (15.50 to 24.0 ppm), Cl- (106 to 438 ppm), and EC (759.50 to 1837.50 µS/cm). Further, a geostatistical tool was used to derive NDDI map of groundwater quality parameters and quantified site-specific variations in parameters, namely SiO2, Cl-, pH, TDS, and EC values. Average NDDI value enrichment was exhibited by SiO2 (0.09, ≈ 0.1) it reflects accretion, while average NDDI values of Cl- (–0.09, ≈–0.1), EC (–0.04), TDS (–0.03), and pH (–0.02), it outlined that by dilution in particular groundwater parameter.

Hydrodynamic Behavior of Particles in a 3D Integral Multi-Jet Spout-Fluidized Bed.

The hydrodynamic behavior of particles in a 3D integral multi-jet spout-fluidized bed has been studied experimentally by particle image velocimetry method. In the cross section of the spouted bed, especially in the annulus, it was found that particle movement can be effectively promoted by adding the integral multi-jet, thus enhancing the radial movement of particles in the annulus and effectively eliminating the dead zone of particle flow in the annulus region. With the decrease of particle handling capacity, the fluidization effect of multi-jets was improved. When the static bed depth was 0.165 m, the enhancement effect of multi-jets on the movement of particles in the spouted bed would be optimal. When the particle diameter was overly small, the fluidization effect of the side jet would be relatively low, while excessive particle diameter would weaken the fluidization effect of the side jet due to the rise in the inertia force of particles. The analysis of the average turbulent kinetic energy and radial velocity of the particles revealed that when the particle diameter is equal to 0.72 mm, the strengthening factor of movement of particles (η) reaches the peak, the turbulence fluctuation of particles in the annulus region reaches the highest, and the fluidization effect of side jets on the particles is the best.

Effect of porous baffle on sloshing pressure distribution in a barge mounted container subjected to regular wave excitation

An experimental study has been carried out to assess the sloshing pressure expected on the side walls of the tank and on top panel. A liquid fill level with an aspect ratio (hs /l, where hs is the static liquid depth and l is the tank length) of 0.488 is considered which corresponds to 75% liquid fill level. In view of suppressing sloshing oscillation and consequent sloshing pressure, the baffle wall configurations such as porous wall at l/2 and porous walls at l/3 and 2l/3 were adopted. Three porosities of 15%, 20.2%, and 25.2% were considered. The sloshing tank is fitted into the freely floating barge of model scale 1:43. The barge is kept inside the wave flume in the beam sea conditions. The effects of wave excitation frequencies and on the sloshing pressure variation have been studied in detail. For comparison purpose, solid wall placed at l/2 (Nasar and Sannasiraj, 2018) is also considered and, the salient results are herein reported.

Utilizing indicator kriging to identify suitable zones for manual drilling in weathered crystalline basement aquifers

Abstract: Manual drilling offers a practical and affordable method of increasing access to groundwater supply in regions struggling with economic water scarcity. However, manual techniques are limited to specific hydrogeological contexts and must be sited appropriately. Indicator kriging is proposed as an interpolation method that builds upon previous efforts to identify suitable zones for manual drilling, particularly in weathered crystalline basement aquifers. This approach allows for heterogeneity within weathering profiles and provides probability mapping of success for regional planning. Modeling was conducted in the Upper East Region of Ghana using available borehole-log data, including: well yield, static water depth, laterite thickness, depth to hard rock, water quality parameters, and the degree of weathering. Indicator kriging interpolations for depth to hard rock predicted binary variables with over 90% accuracy. The model predicts that drilling into highly weathered layers will often be necessary to reach the required depths for groundwater use, emphasizing the importance of percussion techniques. The results suggest that suitable zones occur near Bolgatanga, Bawku, and Zebila, which coincide with historical drilling efforts in the central and eastern portions of the region.

Effects of water depth and water level fluctuation on the total and bio-available element concentrations in riverine reed stands

• Chemical composition in riverine reed stands depends on water depth and water level fluctuation. • Both the total and the bio-available element concentrations increase towards the deep water. • Floods homogenize the surface layer of the sediment, but water depth gradient influences the bio-available fractions. • Chemistry in reed stands can indicate redox conditions in the rhizosphere and anthropogenic pollution sources. This paper evaluates the chemical composition of reed stands grown in different riverine habitats. In addition to the total concentrations, we first present data on the bio-available element fractions of the sediment of reed stands. The results demonstrate clear separation between the plant and sediment samples and reveal the same concentration order of organs in all of the investigated sites irrespective of the water depth and water level fluctuation of the habitats. In reed stands with static water depth gradient, both the total and the bio-available element concentrations of the sediment increase towards the deep water. In habitats regularly flooded by the river, the deposition of suspended matter homogenizes the surface layer of the sediment and, therefore, total element concentrations in that layer is not influenced by the deepening river bed. After the flood event, however, the water depth gradient does influence the bio-available fractions. Finally, it is also demonstrated that chemistry in reed stands can indicate redox conditions in the rhizosphere and anthropogenic pollution sources.