Water Profiles Research Articles

In situ ATR-FTIR spectroscopic imaging of PVC, plasticizer and water in solvent-polymeric ion-selective membrane containing Cd2+-selective neutral ionophore

Concentration profiles of water, polymer and plasticizer in the vicinity of the membrane/water interface were studied by in situ ATR-FTIR spectroscopic imaging with Cd2+-selective membranes as a model system. Two membrane compositions have been studied, both contained polyvinylchloride (PVC) as matrix, 2-nitrophenyl octyl ether (oNPOE) as plasticizer, Cd2+-selective neutral ionophore ETH 1062, and cadmium tetrakis (p-Cl-phenyl)borate as ion-exchanger. One of the membranes contained also a lipophilic electrolyte ETH 500. Prior to measurements, the membranes with overall thickness of 700 μm were equilibrated with water for 1 week. It is shown that in the membranes the surface layers with a thickness of 150 μm are enriched with water, whereas in the bulk of the membranes practically no water was detected. Overall water uptake and also kinetics of evaporation of absorbed water have been studied gravimetrically. Much slower process of leak of the membrane components to water was studied by UV–Vis absorption spectroscopy and gravimetrically, and ion-exchanger and plasticizer are identified as leaking components.

Applying acoustic noise to probe the water column in a dynamic shallow-water environment

Acoustic noise interferometry is applied to retrieve empirical Green's functions (EGFs) from the ambient and shipping noise data acquired in the Shallow Water 2006 experiment on the continental shelf off New Jersey. Despite strong internal wave-induced perturbations of the sound speed in water, EGFs are found on 31 acoustic paths by cross-correlating the noise recorded on a single hydrophone with noise on the hydrophones of a linear array about 3.6 km away. Two fifteen day-long datasets are considered. Dispersion curves of three low-order normal modes at frequencies below 110 Hz are extracted from the EGFs with time-warping technique. The dispersion curves from the first dataset were previously employed to estimate the seabed properties [T. Tan et al., J. Acoust. Soc. Am. 147, EL453–EL459 (2020)]. Here, using this geoacoustic model, we invert the differences between the higher-frequency part of the dispersion curves obtained from the two datasets for the variation of the time-averaged sound speed profile in water between the two observation periods. Results of the passive inversion are compared to the ground truth derived from in situ temperature measurements. The effect of temporal variability of the water column during noise averaging time on EGF retrieval is discussed and quantified.

Mid-frequency propagation and reverberation time series ina deep ice-covered ocean: Modeling and data analysis

Mid-frequency (3.5 kHz) pulses (5 pings, 5 s-long, one per minute) were radiated by an omnidirectional source of opportunity in a deep (3 km) Arctic ocean at 30m depth under ice during the ICEX14 experiment, ALAS component [Williams et al., IEEE-JOE 43, 145–159 (2018)]. Data analysis and modeling results are presented for normalized (re source level) acoustic intensityreceived by an omnidirectional hydrophone located at a 719 m distance from and the same depth as the source. Received time series showed a clear direct blast signal followed by an about 30 s-long reverberation coda. Modeling of the under-ice propagation shows that magnitude of the direct signal is strongly affected by presence of a weak near-surface (within 50 m depths) acoustic channel and by reflectivity of the ice, controlled by its physical properties and acoustical parameters, particularly the ice layer thickness. Analysis of the reverberation coda shows effects of reflections and scattering from rough and/or heterogeneous bottom, as well as reflectivity of the ice layer. Some other effects that may be caused by variability of the sound speed profile and absorption in water are considered as well. Possibilities of inversions for water column, bottom and ice parameters based on this and similar experiments are discussed. [Work supported by ONR.]

Analysis of the influence of larch fibers and particles on selected properties of fiber- and particleboards

Analysis of the influence of larch fibers and particles on selected properties of fiber- and particleboards. The paper presents the results of the research on the effect of the addition of fibers and particles obtained from European larch wood (Larix decidua Mill) from plantations on selected properties of fiber- and particleboards in comparison to the boards of the same structure based on typical industrial raw material (pine wood) uses by European wood based panels industry. The differences were shown in the tests, i.e.: modulus of rupture (MOR), modulus of elasticity in static bending (MOE), internal bond (IB), thickness swelling after 2 and 24 hours soaking in water and density profile. In the MOR and MOE tests, larch boards with a minimum 50% fiber share were characterized by comparable values of the properties determined to pine boards, while in the other variants, boards made of pine wood had better properties. In most cases, the larch boards were characterized by significantly lower values of swelling by thickness (with the exception of boards made of fibers) than boards made of wood from forest cultivation. The density profile of the boards on the cross-section of the plantation raw material did not differ from the boards made of pine raw material.

226Ra, 210Po and lead isotopes in a pit lake water profile in Sweden

A pit lake arises as a consequence of anthropogenic activities in opencast mining areas. These water bodies may be enriched in hazardous stable contaminants and/or in naturally occurring radionuclides depending on the local geological conditions. Mining legacy in Sweden produced hundreds of these pit lakes and most of them are used for recreational purposes in the southern part of the country. In this paper, one pit lake was selected for having enhanced levels of natural radionuclides. Physico-chemical parameters (temperature, pH, oxidation-reduction potential, dissolved oxygen and depth), elemental composition (via Inductive Coupled Plasma Mass Spectrometry) and radiometric characterization (via alpha spectrometry of 226Ra, 210Po and 210Pb) were carried along the depth of a 60 m depth pit lake, with the main aim to describe how natural radionuclides and elements behaves with depth in a non-uraniferous pit lake.Based on observed changes in physico-chemical parameters, a thermocline and a chemocline region were identified at around 10 and 30 m depth respectively. Concerning radionuclides, 226Ra ranged from 75 ± 3 up to 360 ± 12 mBq/kg while 210Po ranged from 11 ± 1 up to 71 ± 3 mBq/kg. 210Pb distribution with depth was also determined via secular equilibrium with 210Po after 2 years and also stable Pb was measured. Disequilibrium 226Ra-210Pb was found and the residence time of 210Pb in the water column was assessed. Additionally, different vertical distributions between 210Pb and Pb were found which points out different sources for different lead isotopes in the water body.

Thermal neutron radiography of a passive proton exchange membrane fuel cell for portable hydrogen energy systems

A proton exchange membrane fuel cell (PEMFC) for portable applications is studied with thermal neutron radiography. The PEMFC operates under passive conditions, with air-breathing cathode and dead-end anode supplied with static ambient air and dry hydrogen, respectively. A columnar cathodic plate favors the mobility of water drops over the cathode surface and their elimination. Thermal neutron images show liquid water build-up during operation of the cell in vertical and horizontal position, i.e. aligned parallel and perpendicular to the gravity field, respectively. Polarization curves and impedance spectroscopy show orientation dependent cell response that can be related with the water profiles. In vertical position, the elimination of drops sliding over the cathode surface as well as natural convection favor lower water contents in the cathode and improve oxygen transport. The vertical cell can be operated for hours in ambient conditions, providing steady power densities above 100 mW cm−2. In horizontal position, natural forces are less effective for water removal leading to 17% decrease in peak power density. The horizontal position is especially adverse if the upper electrode is the cathode, because anode flooding causes cell failure after production of a small amount of water (5 mg cm−2).

Spatially Resolved Root Water Uptake Determination Using a Precise Soil Water Sensor.

To answer long-standing questions about how plants use and regulate water, an affordable, noninvasive way to determine local root water uptake (RWU) is required. Here, we present a sensor, the soil water profiler (SWaP), which can determine local soil water content (θ) with a precision of 6.10-5 cm3 ⋅ cm-3, an accuracy of 0.002 cm3 ⋅ cm-3, a temporal resolution of 24 min, and a one-dimensional spatial resolution of 1 cm. The sensor comprises two copper sheets, integrated into a sleeve and connected to a coil, which form a resonant circuit. A vector network analyzer, inductively coupled to the resonant circuit, measures the resonance frequency, against which θ was calibrated. The sensors were integrated into a positioning system, which measures θ along the depth of cylindrical tubes. When combined with modulating light (4-h period) and resultant modulating plant transpiration, the SWaP enables quantification of the component of RWU distribution that varies proportionally with total plant water uptake, and distinguishes it from soil water redistribution via soil pores and roots. Additionally, as a young, growing maize (Zea mays) plant progressively tapped its soil environment dry, we observed clear changes in plant-driven RWU and soil water redistribution profiles. Our SWaP setup can measure the RWU and redistribution of sandy-soil water content with unprecedented precision. The SWaP is therefore a promising device offering new insights into soil-plant hydrology, with applications for functional root phenotyping in nonsaline, temperature-controlled conditions, at low cost.

Biogeochemical Processes in the Active Layer and Permafrost of a High Arctic Fjord Valley

Warming of ground is causing microbial decomposition of previously frozen sedimentary organic carbon in Arctic permafrost. However, the heterogeneity of the permafrost landscape and its hydrological processes result in different biogeochemical processes across relatively small scales, with implications for predicting the timing and magnitude of permafrost carbon emissions. The biogeochemical processes of iron- and sulfate-reduction produce carbon dioxide and suppress methanogenesis. Hence, in this study, the biogeochemical processes occurring in the active layer and permafrost of a high Arctic fjord valley in Svalbard are identified from the geochemical and stable isotope analysis of aqueous and particulate fractions in sediment cores collected from ice-wedge polygons with contrasting water content. In the drier polygons, only a small concentration of organic carbon (<5.40 dry weight%) has accumulated. Sediment cores from these drier polygons have aqueous and solid phase chemistries that imply sulfide oxidation coupled to carbonate and silicate dissolution, leading to high concentrations of aqueous iron and sulfate in the pore water profiles. These results are corroborated by δ34S and δ18O values of sulfate in active layer pore waters, which indicate the oxidative weathering of sedimentary pyrite utilising either oxygen or ferric iron as oxidising agents. Conversely, in the sediments of the consistently water-saturated polygons, which contain a high content of organic carbon (up to 45 dry weight%), the formation of pyrite and siderite occurred via the reduction of iron and sulfate. δ34S and δ18O values of sulfate in active layer pore waters from these water-saturated polygons display a strong positive correlation (R2 = 0.98), supporting the importance of sulfate reduction in removing sulfate from the pore water. The significant contrast in the dominant biogeochemical processes between the water-saturated and drier polygons indicates that small-scale hydrological variability between polygons induces large differences in the concentration of organic carbon and in the cycling of iron and sulfur, with ramifications for the decomposition pathway of organic carbon in permafrost environments. © Copyright © 2020 Jones, Hodson, Thornton, Redeker, Rogers, Wynn, Dixon, Bottrell and O’Neill.

Physicochemical quality of and Escherichia coli resistance profiles in urban surface waters.

Aquatic ecosystems of urban rivers are contaminated through waste disposal, which poses a public health problem. The objective of this research was to evaluate the quality of water used for recreation and public supply of six rivers in the city of Cascavel - Paraná, including Cascavel, Quati, Bezerra, Antas, Clarito and Amambay. Samples were collected every 4 months in 2017, and their physicochemical and microbiological parameters, as well as resistance profiles of strains of Escherichia coli to antimicrobials distributed by pharmacies of the primary healthcare network, were evaluated. Parameters such as water temperature, turbidity, total nitrogen, total phosphorus, total coliforms and thermotolerant coliforms showed significant differences. The allowed limit for thermotolerant coliforms, which was set by National Environment Council, Resolution 357/2005, was exceeded in all of the six analyzed rivers. It was determined that 48.1% of E. coli strains showed resistance to nine antimicrobial tested. The highest levels of resistance were found for ampicillin (27.7%), tetracycline (27.7%) and amoxicillin (24.0%). The results of this study contribute to the understanding of the hazards associated with the contamination of springs in urban centers with wastewater containing resistant bacteria. Therefore, recovery work is necessary in these areas because of the importance of these water sources for the entire western region of Paraná state.

Functionalized Single-atom Thickness Boron Nitride Membrane for Separation of Arsenite Ion from Water: A Molecular Dynamics Simulation Study

In this research, the performance of functionalized boron nitride nanosheet (BNNS) as a nanostructure membrane with single-atom thickness for the separation of arsenite ions from aqueous solution was examined by molecular dynamics simulation method. The simulated system included a functionalized BNNS placed in an ionic solution containing sodium arsenite, while the external pressures were applied to the system. For the high-water permeability and full ions rejection, the pore of BNNS was functionalized by passivizing pore edge atoms with F and H atoms. Then hydrostatic pressures in the range of 5-100 MPa was applied to the system. During the molecular dynamics simulations, water molecules and arsenite ions were monitored, and some analyses such as water flux, the density profile of water and ion, hydrogen bonds, and radial distribution function were obtained. Results showed that functionalized BNNS was able to conduct water molecules with high permeability through its pore, whereas ions were not able to pass through the pore.

Unified Entrainment and Detrainment Closures for Extended Eddy-Diffusivity Mass-Flux Schemes.

We demonstrate that an extended eddy‐diffusivity mass‐flux (EDMF) scheme can be used as a unified parameterization of subgrid‐scale turbulence and convection across a range of dynamical regimes, from dry convective boundary layers, through shallow convection, to deep convection. Central to achieving this unified representation of subgrid‐scale motions are entrainment and detrainment closures. We model entrainment and detrainment rates as a combination of turbulent and dynamical processes. Turbulent entrainment/detrainment is represented as downgradient diffusion between plumes and their environment. Dynamical entrainment/detrainment is proportional to a ratio of a relative buoyancy of a plume and a vertical velocity scale, that is modulated by heuristic nondimensional functions which represent their relative magnitudes and the enhanced detrainment due to evaporation from clouds in drier environment. We first evaluate the closures off‐line against entrainment and detrainment rates diagnosed from large eddy simulations (LESs) in which tracers are used to identify plumes, their turbulent environment, and mass and tracer exchanges between them. The LES are of canonical test cases of a dry convective boundary layer, shallow convection, and deep convection, thus spanning a broad rangeof regimes. We then compare the LES with the full EDMF scheme, including the new closures, in a single‐column model (SCM). The results show good agreement between the SCM and LES in quantities that are key for climate models, including thermodynamic profiles, cloud liquid water profiles, and profiles of higher moments of turbulent statistics. The SCM also captures well the diurnal cycle of convection and the onset of precipitation.

Land Use Favourability Assessment Based on Soil Characteristics and Anthropic Pollution. Case Study Somesul Mic Valley Corridor, Romania

The Someș Corridor, located in the central Transylvanian region of Romania, is a territory characterised by favourable conditions for habitation and land use with agricultural purposes, offering suitable premises for the development of the settlements and the economic activities taking place in the area. This study aims to identify the parcels of land from outside the built-up area, which can be used as arable land, this particular use being pursued due to the favourability induced by the pedological resources, the morphometrical characteristics of the Someș floodplain and, last but not least, the climatic conditions. GIS technology has been used, enabling the management of the databases representing soil, topography and climatic factors, and thus obtaining the classification of all land parcels using favourability classes for agricultural land use. In order to perform a correct favourability classification, the degree of soil pollution and groundwater pollution have been analysed, using chemical tests of water and soil profiles taken in the area of former abandoned industrial platforms, which are intended to be reintroduced in the local economic use. The highest degree of soil pollution with ammonium and sulphates has been identified in the industrial park from Dej city, on the territory of the former industrial platform of the paper factory, this pollution modifying the quality scores of arable land use, despite the fulfilment of favourable climatic and topographic conditions.

Nano Co-crystal Engineering Technique to Enhance the Solubility of Ezetimibe

Background: Co-crystals have been highly promising for tailoring physicochemical properties of Active pharmaceutical ingredient (API) by coupling with co-former. Objectives: The objective of the present work was to prepare and characterize novel nano co-crystals of Ezetimibe by different methods in various ratios of co-formers and to optimize the formulation based on the enhancement in solubility and dissolution rate. Methods: Ezetimibe nano co-crystals were prepared employing oxalic acid, succinic acid and maleic acid as co-formers by solvent evaporation method and anti-solvent method. Results: Instrumental analysis of co-crystals (DSC, IR, SEM and XRD) was performed to characterize the novel nano co-crystals. Dissolution studies and chemical stability were assessed and compared with pure Ezetimibe. The formulation with maleic acid as a co-former in the molar ratio of Ezetimibe and maleic acid (0.4:0.4) was found to be efficient than oxalic acid and succinic acid. The co-crystal dissolution profile in distilled water containing 0.5% SLS showed 18.8 folds increase in the dissolution efficiency and was found to be 95.2% within 45 min. Conclusion: The results demonstrate feasibility of co-crystallization method using maleic acid as co-former to enhance the solubility of poorly soluble drug Ezetimibe. Key words: Anti-solvent, Co-Formers, Maleic Acid, Oxalic acid, Solubility, Solvent evaporation, Succinic acid.

Tetracycline Resistance Gene Profiles in Red Seabream (Pagrus major) Intestine and Rearing Water After Oxytetracycline Administration.

Marine aquaculture fish and the environment are possible hot spots for the maintenance and spread of antibiotic resistance genes (ARGs). We here show the time courses of changes of six tetracycline resistance genes (tet) in fish rearing seawater and fish intestine in tank experiments. Experimental tanks were prepared as oxytetracycline (OTC) administration tanks and those without OTC. It was found that tet(B), tet(M), and tet(W) were dominant in seawater among the six tet genes. tet(B) and tet(M) abundances increased immediately after OTC administration, indicating that OTC served as a selective pressure to increase the proportion of tet-possessing bacteria. In contrast, the abundance of tet genes in the fish intestine did not differ between the with- and without-OTC administration groups, and clearly was not altered by OTC administration. Profile changing of tet in seawater and fish intestine did not synchronize. These observations suggested that the dynamics of intestinal tet-possessing bacteria do not directly reflect the environment, but reflect selection within the intestine.

Influence of Vertical Heterogeneities in the Canopy Microenvironment on Interannual Variability of Carbon Uptake in Temperate Deciduous Forests

AbstractVegetation structure and function are key design choices in terrestrial models that affect the relationship between carbon uptake and environmental drivers. Here, we investigate how representing canopy vertical structure in a terrestrial biosphere model—that is, micrometeorological, leaf area, and leaf water profiles—influences carbon uptake at five U.S. temperate deciduous forest sites in July. Specifically, we test whether the interannual variability (IAV) of gross primary productivity (GPP) responds differently to four abiotic environmental drivers—air temperature, relative humidity, incoming shortwave radiation, and soil moisture—using either a Community Land Model multilayer canopy model (CLM‐ml) or a big‐leaf model (CLM4.5/CLM5). We conclude that vertical leaf area and microclimatic profiles (temperature, humidity, and wind) do not impact GPP IAV compared to a single‐layer model when plant hydraulics is excluded. However, with a mechanistic representation of plant hydraulics there is vertically varying water stress in CLM‐ml, and the sensitivity of carbon uptake to particular climate variables changes with height, resulting in dampened canopy‐scale GPP IAV relative to CLM4.5. Dampening is due to both a reduced dependence on soil moisture and opposing climatic forcing on different leaf layers. Such dampening is not evident in the single‐layer representation of plant hydraulic water stress implemented in the recently released CLM5. Overall, both model representations of the canopy fail to accurately simulate observed GPP IAV and this may be related by their inability to capture the upper range of observed hourly GPP and diffuse light‐GPP relationships that cannot be resolved by canopy structure alone.

The control of hydrogen sulfide on benthic iron and cadmium fluxes in the oxygen minimum zone off Peru

Abstract. Sediments in oxygen-depleted marine environments can be an important sink or source of bio-essential trace metals in the ocean. However, the key mechanisms controlling the release from or burial of trace metals in sediments are not exactly understood. Here, we investigate the benthic biogeochemical cycling of iron (Fe) and cadmium (Cd) in the oxygen minimum zone off Peru. We combine bottom water and pore water concentrations, as well as benthic fluxes determined from pore water profiles and from in situ benthic chamber incubations, along a depth transect at 12∘ S. In agreement with previous studies, both concentration–depth profiles and in situ benthic fluxes indicate a release of Fe from sediments to the bottom water. Diffusive Fe fluxes and Fe fluxes from benthic chamber incubations (−0.3 to −17.5 mmol m−2 yr−1) are broadly consistent at stations within the oxygen minimum zone, where the flux magnitude is highest, indicating that diffusion is the main transport mechanism of dissolved Fe across the sediment–water interface. The occurrence of mats of sulfur-oxidizing bacteria on the seafloor represents an important control on the spatial distribution of Fe fluxes by regulating hydrogen sulfide (H2S) concentrations and, potentially, Fe sulfide precipitation within the surface sediment. Rapid removal of dissolved Fe after its release to anoxic bottom waters hints at oxidative removal by nitrite and interactions with particles in the near-bottom water column. Benthic flux estimates of Cd suggest a flux into the sediment within the oxygen minimum zone. Fluxes from benthic chamber incubations (up to 22.6 µmol m−2 yr−1) exceed diffusive fluxes (&lt;1 µmol m−2 yr−1) by a factor of more than 25, indicating that downward diffusion of Cd across the sediment–water interface is of subordinate importance for Cd removal from benthic chambers. As Cd removal in benthic chambers covaries with H2S concentrations in the pore water of surface sediments, we argue that Cd removal is mediated by precipitation of cadmium sulfide (CdS) within the chamber water or directly at the sediment–water interface. A mass balance approach, taking the contributions of diffusive and chamber fluxes as well as Cd delivery with organic material into account, suggests that CdS precipitation in the near-bottom water could make an important contribution to the overall Cd mass accumulation in the sediment solid phase. According to our results, the solubility of trace metal sulfide minerals (Cd ≪ Fe) is a key factor controlling trace metal removal and, consequently, the magnitude and the temporal and spatial heterogeneity of sedimentary fluxes. We argue that, depending on their sulfide solubility, sedimentary source or sink fluxes of trace metals will change differentially as a result of declining oxygen concentrations and the associated expansion of sulfidic surface sediments. Such a trend could cause a change in the trace metal stoichiometry of upwelling water masses with potential consequences for marine ecosystems in the surface ocean.

Flood Mapping Uncertainty from a Restoration Perspective: A Practical Case Study

Many hydrologic studies that are the basis for water resources planning and management rely on streamflow information. Calibration and use of hydrologic models to extend flow series based on rainfall data, perform flood frequency analysis, or develop flood maps for land use planning and design of engineering works, such as channels, dams, bridges, and water intake, are examples of such studies. In most real-world engineering applications, errors in flow data are neglected or not adequately addressed. However, because flows are estimated based on the water level measurements by fitted rating curves, they can be subjected to significant uncertainties. How large these uncertainties are and how they can impact the results of such studies is a topic of interest for researchers, practitioners, and decision-makers of water resources. The quantitative assessment of these uncertainties is important to obtain a more realistic description of many water resources related studies. River restoration in many areas is limited by data availability and funding. A means to assess the uncertainty of flow data to be used in the design and analysis of river restoration projects that is cost effective and has minimal data requirements would greatly improve the reliability of river restoration design. This paper proposes an assessment of how uncertainties related to rating curves and frequency analysis may affect the results of flood mapping in a real-world application to a small watershed with limited data. A Bayesian approach was performed to obtain the posterior distributions for the model parameters and the HEC-RAS (Hydrologic Engineering Center-River Analysis System) hydraulic model was used to propagate the uncertainties in the water surface elevation profiles. The analysis was conducted using freely available data and open source software, greatly reducing traditional analysis costs. The results demonstrate that for the study case the uncertainty related to the frequency analysis study impacted the water profiles more significantly than the uncertainty associated with the rating curve.

Synthesis of Poly(ethylene glycol) Grafted Polyamidoamine Dendrimer Hydrogels and Their Temperature and pH Sensitive Properties

PEG-based smart hydrogels have excellent properties and are widely used in the drug delivery, tissue engineering and other fields. In this article, a temperature responsive and pH sensitive dual responsive hydrogel which is suitable for water plugging and profile control in the Daqing oil field was prepared via graft copolymerization using polyethylene glycol (Mn = 600, 1000, and 2000) and polyamidoamine (PAMAM) as raw materials. The structure and properties of the products were characterized using infrared, 1H NMR and UV–Vis spectroscopy, end group titration, scanning electron microscopy (SEM) and swelling behavior tests. The influence of the molecular weight of the PEG precursor on the critical phase transition temperature (LCST) and pH sensitivity of the hydrogel were systematically studied. The experimental results showed that when the molecular weight of the PEG precursor was varied in the range of 600–2000, the hydrogel showed obvious temperature sensitivity and the LCST increased from 40 to 50°C. When the pH was in the range of 8–11, the hydrogel exhibited obvious pH sensitivity, swelling under alkaline conditions under acid shrinkage conditions, and the swelling ratio of the hydrogel increased upon increasing the molecular weight of the PEG precursor. The hydrogel was switched at temperatures between 10 and 60°C, pH values between 3 and 11, and the swelling behavior of the hydrogel showed good reversibility for swelling–deswelling, which provides the possibility for water plugging and profile control in an oil field. SEM showed that the hydrogels in their dry state had a spherical structure and as the molecular weight of the PEG precursor increased, the size of the spherical particles decreased and the porosity increased.

Effect of Change in Land-use to High Pattern of Inundation on Sub-River System of Lowland Urban River

Flooding is a temporal condition of surface water where the level and debit are exceeding a specific allowable limit. Urban city flooding is an effect of unbalance city environment related to regulation function. Vulnerability to increasing of population and change of land use at rural area and urbanisation to the flood-prone area, illegal shelter, land development on the water catchment area, increase in population density are the most common source of flooding on an urban area. This paper presents a study on the effect of changing in land use to high inundation pattern on river sub-system (SRS) of Bendung River in Palembang City. The data is taken based on a digital elevation model (DEM) generated from high point data set from a Compact Airborne Spectrographic Imager (CASI) sensor. The model used in this study was a hydrological model using SMADA 6.0 and DUFLOW 3.6 for rainfall-runoff model and analysis of river system generating surface water profile. The ArcGIS was used to construct a surface water model related to DEM data to obtain inundated area, inundation maps, inundation height and geospatial analysis. Four scenarios are applied in this study area which was changing the type of land use to a green area, changing the type of land use to a settlement area, free up 30 m riverbank to a green area and free up 100 m riverbank to a green area. From this study, the change in runoff coefficient, C value does not significantly reduce the inundation area in the area with more than 80% relatively flat topography. Increase the C value by 10% resulted in an increase on the puddle area to 9.4%, while the flood area with an altitude of more than 1 m increased to 359%. The results of scenario with land used change 10% - 20%, contributed to the increase in the flood area of 9.4% - 12.1%. So that to reduce the high pattern inundation a structural approach combined with a non-structural approach should be enforced and implemented. Besides, land-use changes will be significant to reduce flooding when land consolidation is applied to a sub-river system (SRS).

Lacustrine Groundwater Discharge Through Giant Pockmarks (Lake Neuchatel, Switzerland)

Pockmarks are circular depressions on the floor of oceans and lakes and constitute potential hot spots of gas ebullition and/or groundwater discharge. Marine pockmarks are well studied, whereas lacustrine pockmarks are virtually unexplored. In Lake Neuchatel (Switzerland) four giant pockmarks of 80 to 150 m in diameter are located along the northern shore and adjacent to the karst system of the Jura Mountains. Two pockmarks have a ~60 m-deep chimney filled with mud; two are funnel-shaped 12 m and 29 m deep holes. We present evidence for the presence of groundwater in the pockmark chimneys and active lacustrine groundwater discharge (LGD) at both pockmark types. Temperature, electrical conductivity and calcium concentrations of the pore water in the chimneys show values typical for karst water (maximal sampling and profiling depth: 41 m into the pockmark) and contrast strongly with the properties of the lake water. TOC and TIC indicate that the chimney mud is homogenized and composed of liquefied sediments from the entire deglacial to Holocene lacustrine sediment succession. Mini mud volcanoes apparent on the suspension surface imaged with a remotely operated vehicle (ROV) localize the groundwater exit points and confirm LGD. LGD is further corroborated by electrical conductivity anomalies detected above the lutoclines and within a funnel-shaped pockmark during the ROV survey. We conclude that the giant pockmarks in Lake Neuchatel represent a type of subaquatic springs that connect the water body of the lake with the karst system. A next essential research step will be to quantify LGD via the pockmarks in order to assess their lake-wide relevance. This study underlines the existing need for research on the connectivity of lakes and oceans with groundwater systems for completing our understanding of the hydrological cycle.