Letteratura scientifica selezionata sul tema "Sediment salinity"

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Articoli di riviste sul tema "Sediment salinity"

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Warsito, Kevin Wijaya, e Wati Astriningsih Pranoto. "ANALISIS KECEPATAN JATUH SEDIMEN PADA SUNGAI CIBEET, JAWA BARAT". Jurnal Muara Sains, Teknologi, Kedokteran dan Ilmu Kesehatan 5, n. 1 (4 maggio 2021): 45. http://dx.doi.org/10.24912/jmstkik.v5i1.7649.

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Cibeet River is one of the branch of the Citarum river in West Java province with a length of 101 km. Cibeet River is one of the rivers supplying water and sediment to the West Tarum irrigation channel or known as the Kalimalang. In this research, the sample used was in the form of mud taken at the Cibeet River Estuary. This research is focused on settling velocity which is a parameter for sedimentation in order to improve numerical modeling and conceptual understanding of sediment dynamics, especially mud. Sediment research is carried out in the Soil Mechanics laboratory and Hydraulics laboratory. Bottom withdrawal tube experiments were carried out using 5 types of salinity and 6 kinds of sediment concentrations. The purpose of the study was to obtain settling velocity and compare laboratory results with the Stokes law approach and compare the relationship between settling velocity with sediment concentration and salinity. The optimum salinity is obtained at 15 ‰, and the optimum sediment concentration at 4700 ppm with an average fall speed of 37,28 mm / s. The results from the laboratory are not in accordance with the Stokes law due to the influence of flocculation from the cohesive nature of the mud sediment, so that using the Stokes law approach cannot calculate the velocity of falling sediment on the mud. Keywords: concentration; salinity; sediment; settling velocity AbstrakSungai Cibeet merupakan salah satu anak sungai dari sungai Citarum di provinsi Jawa Barat dengan panjang 101 km. Sungai Cibeet merupakan salah satu sungai pemasok air dan sedimen ke saluran irigasi Tarum Barat atau dikenal sebagai Kalimalang. Pada penelitian ini, sampel yang digunakan berupa lumpur yang diambil di Muara Sungai Cibeet. Penelitian ini difokuskan pada kecepatan jatuh sedimen yang merupakan parameter untuk sedimentasi demi meningkatkan permodelan numerik dan pemahaman konsep dari dinamika sedimen terutama lumpur. Penelitian ini dilakukan di laboratorium Mekanika Tanah dan laboratorium Hidrolika, memakai bottom withdrawal tube, dilakukan dengan menggunakan 5 macam jenis salinitas dan 6 macam konsentrasi sedimen. Penelitian ini membandingkan antara hasil laboratorium dengan pendekatan yaitu hukum Stokes serta membandingkan hubungan antara konsentrasi sedimen dengan salinitas. Untuk salinitas didapat optimum pada saat 15‰, dan konsentrasi sedimen yang optimum pada saat 4700 ppm dengan kecepatan jatuh rata-rata 37,28 mm/s. Hasil dari laboratorium tidak sesuai dengan pendekatan hukum stokes dikarenakan adanya pengaruh flokulasi dari sifat sedimen lumpur yang kohesif, sehingga menggunakan pendekatan hukum stokes tidak bisa untuk menghitung kecepatan jatuh sedimen pada lumpur.
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Hamzah, Faisal, Nuryani Widakti e Frida Sidik. "The Growth of Mangroves in Created Wetland in the Porong River, East Java, Indonesia". Journal of Tropical Crop Science 2, n. 1 (1 febbraio 2015): 10–15. http://dx.doi.org/10.29244/jtcs.2.1.10-15.

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Mangrove plantation projects have been established in the created mangrove wetland in the mouth of the Porong River, East Java, in parallel with the construction of reclamation area for LUSI mud dumping area. This study was aimed to assess the growth of planted mangrove in a created mangrove wetland in relation to the environmental parameters, which are sediment salinity, sediment fraction, pore water salinity, pH/eH, and total organic matter (TOM) in the sediment. Periodical measurement of mangrove growth Avicennia sp. and the environmental parameters were undertaken in the created wetland and in the mud flats of intact mangrove forest nearby the created wetland as the natural reference in July to November 2012. We found that sediments in the created wetland had different characteristics of sediment fractions, sediment salinity and TOM compared to sediments in the mud flats of intact forests. Sand dominated sediments with low TOM and higher water salinity in the created wetland as compared to those in the mud flats affected growth rate of mangroves in study sites. We suggest that TOM and salinity are important factors that contribute to the growth of mangroves in the Porong River. Keywords: Mangrove, salinity, Porong River, total organic matter.
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Spears, Bryan M., James E. Saunders, Irvine Davidson e David M. Paterson. "Microalgal sediment biostabilisation along a salinity gradient in the Eden Estuary, Scotland: unravelling a paradox". Marine and Freshwater Research 59, n. 4 (2008): 313. http://dx.doi.org/10.1071/mf07164.

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Microalgal biostabilisation of cohesive sediments via the production of extracellular polymeric substances (EPS) has been well documented in intertidal ecosystems and represents a key ecosystem service with respect to the regulation of sediment transport. However, recent ecosystem comparison studies have uncovered a paradox in which sediment stability is commonly observed to be lower in freshwater ecosystems (compared with estuarine ecosystems) even though sediment EPS concentrations and microalgal biomass are high. Using a combination of freshwater and estuarine field and mesocosm techniques, the relative and interactive roles of salinity and the production of EPS (carbohydrate concentration) by benthic microalgae in the mediation of sediment stability in the Eden River catchment (river, mudflat and saltmarsh) were assessed. Sediment stability apparently increased with salinity from river (42.43 N m–2 surface stagnation pressure; salinity 0) to mudflat (98.65 N m–2; salinity 25) to saltmarsh (135.48 N m–2; salinity 46). The opposite trend was observed in sediment chlorophyll a and carbohydrate concentrations, indicating that salinity is the main variable driving sediment stability across the ecosystems under moderate EPS concentrations. Observations from mesocosm experiments highlighted the individual and combined importance of salinity and EPS in biostabilisation, with the largest increase in sediment stability observed following combined additions (25-fold increase compared with the control). The biogeochemical processes responsible, and their role in buffering phosphorus transport across the freshwater–saltwater transitional zone, are discussed.
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Yatmadi, Denny, Muslim Muin, Ricky L. Tawekal, Heru Nur Alam e Arung Bahari Muslim. "Cohesive Sediment Simulation in Kanal Banjir Barat Using MuSed3D, Non-Orthogonal Boundary Fitted Sediment Transport Model". IOP Conference Series: Earth and Environmental Science 1065, n. 1 (1 luglio 2022): 012014. http://dx.doi.org/10.1088/1755-1315/1065/1/012014.

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Abstract Fine-grained cohesive sediments dominate sedimentation in the lowland area. In the Density Induced Current process, where seawater intrusion occurs, the fine-grained cohesive sediment will be easily flocculated by saltwater and settles rapidly. There are complex problems related to sedimentation in the rivers of Jakarta in the downstream area, which is influenced by tides and the dominance of cohesive sediment. Due to the complex process in the estuary, salinity intrusion will affect the settling velocity. And then, the flocculation process, the river’s geometry, will also affect sediment deposition. A proper model is needed to simulate the sedimentation in this area. This study aimed to investigate the distribution of cohesive sedimentation using 3D hydrodynamic and sediment transport model called MuSed 3D. This model will be applied to the Kanal Banjir Barat (KBB) river, Jakarta. The model result shows salinity values in the range of field observations for TSS and salinity. Salinity model present from 1 till 10 ppt and TSS present from 9,8 until 14,2 ppm. This study concludes that the dispersion of sediment cohesive on river and estuary affected by Density Induced Current also depends on salinity and TSS value.
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Tsai, CH, e SC Hwang. "Flocculation of sediment from the Tanshui River estuary". Marine and Freshwater Research 46, n. 1 (1995): 383. http://dx.doi.org/10.1071/mf9950383.

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Experiments on the flocculation of fine-grained sediments from the Tanshui River estuary, Taiwan, were carried out. The effects of fluid shear, sediment concentration and salinity on floc growth were investigated. The ranges of these parameters were 12.5 to 400 s-1 for the shear, 50 to 600 mg L-1 for the sediments concentration and 0% to 100% sea water for the salinity. The results showed the following. (1) The time required to reach a steady state ranges from 2 to 44 h and median floc sizes range from 100 to 520 μm. (2) The steady-state median floc size decreases with the increase in sediment concentration. (3) The floc size increases as the shear increases. (4) Increasing the proportion of sea water from 0% to 50% decreases the floc size to one-fourth of that of freshwater flocs, and a further increase in salinity does not decrease floc size significantly. (5) The time required to reach a steady state decreases with the decrease in shear, the increase in sediment concentration and the increase in salinity. (6) The larger the steady-state flocs, the longer they take to form. Comparison of these results with those obtained in similar studies of Lake Erie sediments shows that the flocculation properties of Tanshui sediments are substantially different from those of Lake Erie sediments. Tanshui sediments are much more difficult to aggregate, but once flocs are formed they are larger. The reasons why different types of sediment behave differently should be studied further.
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Yao, Suni. "River water injecting into sea: Movement of sediments in stable stratified flows". Theoretical and Natural Science 34, n. 1 (2 aprile 2024): 8–18. http://dx.doi.org/10.54254/2753-8818/34/20241125.

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The study of sediment movement in a stably stratified (each layer is less dense than the one below it) fluid is important for applications such as airborne virus transport, contaminant transport, and sediment settling in river inlets. This project will quantify the effect of sediment-driven instability on the horizontal motion of sediment in a stably stratified fluid. Experiments are designed to analyze this process by adding sediment-rich brine-free water to sediment-free brine, where salinity differences are used to construct stably stratified fluids. The experiments are done with salinity same as salty water with concentration of sediments derived from linear stability analysis. This work provide baseline experiments for sediment settling in a stably stratified fluids for numerical validations in the future.
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Torres-Alvarado, María del Rocío, Teresa Pérez Muñoz e Neivy Betsabet Maldonado-Vela. "Methanogenesis in sediments of a tropical coastal wetland: a culture-dependent method". Revista de Biología Tropical 72, n. 1 (16 aprile 2024): e57126. http://dx.doi.org/10.15517/rev.biol.trop..v72i1.57126.

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Introduction: Methanogenic archaea (MA), participate in the anaerobic mineralization of organic matter in mangrove sediments, their activity is related to atmospheric warming due to the production of methane; several environmental variables can influence the presence of MA and methane production in these sediments. Objective: To analyze, through culture-dependent techniques, viable methanogenic archaea (VMA) in the sediments, and the production of methane from acetate in different climatic periods in the mangrove El Morro-La Mancha, Veracruz, Gulf of Mexico. Methods: From May to November 2019, following a salinity transect, sediment samples from El Morro-La Mancha mangrove were collected at three locations, in three different climatic seasons, dry (May), rainy (October) and northern (November) (N = 9). VMA in the sediments was quantified using the Most Probable Number (MPN) technique with acetate and methanol as substrates. The influence of sulfate on methane production was analyzed from acetate in microcosm by gas chromatography and the chemical variables of salinity, pH, Eh, carbohydrates, organic content, and carbonates in the sediments were evaluated. Results: The abundance of VMA was 102 to 108 MPN/g of wet sediment, higher than that reported in other studies, this abundance was higher when methanol (104-108 MPN/g sediment) was used as substrate, compared to acetate (102-105 MPN/g sediment); methane production in the microcosms increased in sulfate-free conditions (29.78-929.75 nmol CH4/month) and in the sediments of the rainy season. Conclusion: The influence of the chemical conditions of the mangrove sediments on the methanogenic dynamics is highlighted, determining that in the rainy season, the decrease in salinity, more electronegative Eh, and the increase in organic fractions favored the methanogenesis. Objetive: To analyze, through culture-dependent techniques, the abundance of MA and the production of methane in different climatic periods in the mangrove El Morro-La Mancha, Veracruz, Gulf of Mexico. Methods: From May to November 2019, following a salinity transect, sediment samples from El Morro-La Mancha mangrove were collected at three sampling locations, in three different climatic seasons, dry (May), rainy (October) and northern (November) (n=9). The methanogenic abundance in the sediments was quantified using the Most Probable Number (MPN) technique with acetate and methanol as substrates; methane production was analyzed from acetate by gas chromatography and the chemical variables of salinity, pH, Eh, carbohydrates, organic content and carbonates in the sediments were evaluated. Results: The abundance of MA was 102 to 108 cells/g of wet sediment, higher to that reported in other studies, this abundance was higher when methanol (104 - 108 cells/g sediment) was used as substrate, compared to acetate (102 - 105 cells/sediment); methane production increased in rains with 13% compared to dry. Conclusion: Highlighted the influence of the chemical conditions of the mangrove sediments on the methanogenic dynamics, determining that in the rainy season, the decrease in salinity, Eh more electronegative and the increase in organic fractions favored both methanogenic abundance as methane production.
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Zhang, Xiaolei, Xin Liu, Haoran Wu, Shuyu Liu, Yu Zhu, Zhengzheng Bi e Zhiheng Xu. "Experimental Study on the Incipient Movement of Muddy Clay under Different Salinity Conditions". Scientific World Journal 2022 (5 settembre 2022): 1–13. http://dx.doi.org/10.1155/2022/5245928.

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In order to understand the incipient movement of muddy clay under different salinity conditions, three series of flume tests were performed on incipient movement of muddy clay, including tests on incipient movement of salt-free clay mud under salt water conditions (salt water-salt-free clay mud), incipient movement of salt clay mud under salt water conditions (salt water-salt clay mud), and incipient movement of salt clay mud under freshwater conditions (freshwater-salt clay mud), using a circulating flume, in which the salinity of the water body or cohesive sediment varies from 0 to 40%. Based on the particle image velocimetry system and digital image gray processing technology, the gray curves of water near the clay mud bed surface with the velocity were plotted to quantitatively differentiate the incipient velocity of the sediment for each test. The experimental results showed that the higher the salinity of the water body or cohesive sediments is, the more difficult it is to start moving. There is a logarithmic relationship between the incipient velocity of cohesive sediments and the salinity of the water or cohesive sediments. The incipient velocity increases sharply at a salinity of 0∼10% and slowly at a salinity of 10∼40%. At the same salinity, the incipient velocity of salt clay mud under freshwater conditions is the largest, followed by that of salt clay mud under salt water conditions, while that of salt-free clay mud under salt water conditions is the smallest. In addition, the flow turbulence characteristics were analyzed under the critical conditions of the onset of muddy clay. Ultimately, an empirical formula to calculate the critical incipient velocity of muddy clay is proposed by introducing the salinity. In this study, salinity is included as a reference variable, which expands the research scope of sediment initiation and provides a reference for the study of estuary dynamics.
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Singare, Pravin U., M. V. A. Ansari e N. N. Dixit. "Assessment of Physico-Chemical Properties of Sediments Collected along the Mahul Creek near Mumbai, India". International Letters of Natural Sciences 16 (maggio 2014): 54–61. http://dx.doi.org/10.18052/www.scipress.com/ilns.16.54.

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The present study was performed for the period of one year from January 2013 to December 2013 in order to understand the physico-chemical properties of sediments samples collected along the Mahul Creek of Mumbai. The annual average pH value of the creek sediments was recorded as 5.38. It is feared that such low pH value of sediment might increase the acidity of creek water thereby triggering the heavy metal toxicity which will further reduced survivorship in fish through chronic stress and affect the reproductive partner. The annual average salinity content of the sediment was recorded as 4601.17 ppm. It is important here to note that the high salinity of the sediment may increase the salinity level of creek water which is considered as a major stress factor for most freshwater organisms including crustaceans. The average annual concentration of phosphate in the creek sediment was found to 480.39 ppm. Such high concentration of phosphate in the creek sediments might accelerate the process of eutrophication. From the results it appears that as India moves towards stricter regulation of industrial effluents to control water pollution, greater efforts are required to reduce the risk due to the toxic pollutants which are released into the ecosystems.
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Singare, Pravin U., M. V. A. Ansari e N. N. Dixit. "Assessment of Physico-Chemical Properties of Sediments Collected along the Mahul Creek near Mumbai, India". International Letters of Natural Sciences 16 (30 maggio 2014): 54–61. http://dx.doi.org/10.56431/p-23xkb4.

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Abstract (sommario):
The present study was performed for the period of one year from January 2013 to December 2013 in order to understand the physico-chemical properties of sediments samples collected along the Mahul Creek of Mumbai. The annual average pH value of the creek sediments was recorded as 5.38. It is feared that such low pH value of sediment might increase the acidity of creek water thereby triggering the heavy metal toxicity which will further reduced survivorship in fish through chronic stress and affect the reproductive partner. The annual average salinity content of the sediment was recorded as 4601.17 ppm. It is important here to note that the high salinity of the sediment may increase the salinity level of creek water which is considered as a major stress factor for most freshwater organisms including crustaceans. The average annual concentration of phosphate in the creek sediment was found to 480.39 ppm. Such high concentration of phosphate in the creek sediments might accelerate the process of eutrophication. From the results it appears that as India moves towards stricter regulation of industrial effluents to control water pollution, greater efforts are required to reduce the risk due to the toxic pollutants which are released into the ecosystems.
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Tesi sul tema "Sediment salinity"

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Monabbati, Mehran. "Effect of salinity and organic matter content of sediments on the sediment-water exchange of arsenic". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0005/NQ41249.pdf.

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Cakiroglu, Ayse Idil. "Salinity Inference In Inland Turkish Shallow Lakes On Paleoecology Using Sub-fossil Cladocera". Phd thesis, METU, 2013. http://etd.lib.metu.edu.tr/upload/12615450/index.pdf.

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In the current study, sub-fossil Cladocera collected from the surface sediment of 44 shallow lakes spanning over five latitudes from north to south of Turkey using snap-shot methodology revealed strong impact of salinity on cladoceran community structure. To see the whole picture, sediment cores collected from six of the lakes and long-term monitoring data from two of the lakes were also investigated. Contemporary cladocerans and sub-fossil assemblages were compared to reveal that their responses to salinity changes were highly similar. This lead us to use sub-fossil cladocerans and salinity data from water column together while generating the calibration data set using ordination techniques. Salinity transfer function models were developed utilising weighted averaging techniques. The developed salinity transfer function was applied to cladocera assemblages from dated sediment cores. Hindcasting of the salinity inference model was performed using monitoring data and the reconstructed salinities from two central Anatolian lakes and reflected good linear correlation with the known lake salinity history. This thesis has confirmed that sub-fossil Cladocera is a valuable indicator of historical salinity change and marker for the monitoring of lakes. For the first time, the lake environmental variables and sub-fossil cladoceran species composition from the surface sediments of Turkish shallow lakes were studied and a salinity transfer function was developed to elucidate past salinity change. The approach of the current study has been proven to be reliable while interpreting past salinity conditions. Since monitoring programmes are scarce in Turkey, paleolimnological analyses would be beneficial especially when defining effective restoration strategies.
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Yang, Hua. "Influences of tidal and subtidal currents on salinity and suspended-sediment concentration in the Delaware Estuary". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 105 p, 2008. http://proquest.umi.com/pqdweb?did=1459923351&sid=13&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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Stephens, Christine Elizabeth. "Marine fish carbonates : contribution to sediment production in temperate environments". Thesis, University of Exeter, 2016. http://hdl.handle.net/10871/26195.

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In the past, oceans have strongly influenced atmospheric CO2 levels through organic and inorganic carbon cycling. The inorganic carbon pump relies on the formation of calcium carbonate which releases CO2 into the surface ocean and traps alkalinity in solid form which sinks to deeper ocean layers and sediments. After sinking, calcium carbonate can either then become trapped in the sediments or dissolve increasing the alkalinity of deeper ocean layers. The net effect is of acidifying surface oceans and encouraging release of CO2 to the atmosphere. The present thesis focuses on marine teleost (bony) fish in temperate areas as previously poorly understood but potentially major producers of calcium carbonate in the ocean. Fish in temperate areas may be contributing to carbonate sediment production and as such the inorganic carbon pump. Prior to this thesis only tropical fish have been investigated as major piscine sediment producers. The present thesis describes the composition and morphology of carbonates produced by many different species of temperate fish providing a basis for the understanding the fate of these carbonates in the environments and their potential contribution to sediment production and the inorganic carbon cycle. Characteristics of carbonates produced by fish in the wild were fairly consistent within a species upon examination of carbonates produced by poor cod (Trisopterus minutus) over the course of a year. However, despite the likely consistent and distinct characteristics of fish carbonates, little evidence of them was found in temperate shallow sediments beneath pens of farmed Atlantic salmon (Salmo salar) where there theoretically should be very high production rates. Reduced salinity, often a feature of temperate areas compared to tropical areas, was found to reduce production rates of carbonate from fish compared to higher salinities. However, salinity reductions below the ocean average of 35 psu (practical salinity units) had less impact on production rates than increases above 35 psu. As such it is argued that production rates in temperate environments should still be relatively high considering high fish biomasses in some temperate regions and could still mean fish in temperate areas are an important source of carbonate production and potential sediment production.
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Silva, Camila MagalhÃes. "Detection Aeromonas spp. in surface water samples and sediment along a salinity gradient in river estuary Cocà - CearÃ". Universidade Federal do CearÃ, 2009. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=13386.

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This research work was designed to detect the presence of Aeromonas in the Cocà River estuary, Fortaleza, Cearà State, Brazil. The database consisted of 30 samples of the riverâs surface water and 30 samples of the riverâs sooil, in the period from September, 2007 to April, 2008.. They were amenable, simultaneously, to counting of bacteria on Agar Gelatin Phosphate Salt (GSP) plus 20μg/mL of ampicilim (UFC/mL or UFC/g) The results showed dissemination of Aeromonas in the estuary. The counts for the water samples varied from 10 to 7,050 and from 25 to 38,500 UFC/mL at points A and B respectively; and from 100 to 37,500 UFC/g, and 1,200 to 43500 UFC/g at points A and B respectively. At point C, the counts for water and sediment were smaller than 10 UFC per ml or gram in all samples The occurrence of the greatest indices of Aeromonas in April, at the height of the rainy season, and the lowest in Septemer, at the height of the dry season, suggests there to be a probable seasonality of bacteria density in the studied environment. Among the 41 isolated strains were found the species A. caviae, A. sobria, A. trota, A. salmonicida and A. allossacharophyla. All the strains of Aeromonas sp. were found to be sensitive to cloranfenicol and ceftriaxona except for ampicillim, to which they showed 100% resistance.All the stirps showed resistance to two out of the nine tested antibiotics. After the Curingâ technique, the eritromicina resistance seems to be of plasmidian origin.
Este projeto teve como objetivo principal a pesquisa de Aeromonas spp. em Ãgua de superfÃcie e sedimento em trÃs pontos distintos ao longo do rio CocÃ, CearÃ. Foram realizadas coletas no perÃodo de outubro de 2007 a abril de 2008 gerando um total de 30 amostras de Ãgua e 30 de sedimento. A quantificaÃÃo da comunidade bacteriana pertencente ao gÃnero Aeromonas foi feita atravÃs de plaqueamento direto sobre Agar Gelatina Fosfato Sal (Agar GSP acrescido de 20μg/mL de ampicilina). Nas amostras de Ãgua, os valores obtidos variaram de 10 a 7.050 UFC/mL e de 25 a 38.500 UFC/mL nos pontos A e B, respectivamente. Nas amostras de sedimento, as contagens variaram de 100 a 37500 UFC/g e 1.200 a 43.500 UFC/g nos pontos A e B, respectivamente. Nas amostras de Ãgua e sedimento do ponto C, os valores foram menores que 10 UFC (por mL ou g) em todas as coletas. As maiores contagens foram verificadas no mÃs de abril, perÃodo de chuva, e as menores no mÃs de setembro, perÃodo de estiagem. Foram feitos isolamentos e apÃs identificaÃÃo as estirpes foram submetidas à teste de antibiograma e à tÃcnica da âcuraâ do plasmÃdio. Dentre as 41 cepas isoladas, foram identificadas as espÃcies A. caviae, A. sobria, A. trota, A. salmonicida e A. allossacharophyla. Todas as cepas se mostraram sensÃveis ao cloranfenicol e ceftriaxona. Todas as estirpes apresentaram resistÃncia a, pelo menos, dois dos nove antibiÃticos testados. ApÃs a tÃcnica de cura, a maior parte da resistÃncia a eritromicina ficou caracterizada como de origem plasmidial.Conclui-se que o estuÃrio do Rio Cocà està contaminado por Aeromonas e que muitas delas apresentam resistÃncias a antibiÃticos denotando um ambiente poluÃdo e de risco para a populaÃÃo que usa suas Ãguas para lazer, pesca ou outra atividade qualquer.
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Cadaret, Erik M. "Vegetation Canopy Cover Effects on Sediment and Salinity Loading in the Upper Colorado River Basin Mancos Shale Formation, Price, Utah". Thesis, University of Nevada, Reno, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10001481.

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With future climate change and increased water demand and scarcity in the Colorado River Basin, the Bureau of Reclamation estimates that the costs of salinity damage will increase for Colorado River users and will exacerbate the current salinity challenges. This study focuses on saline and sodic soils associated with the Mancos Shale formation in order to investigate the mechanisms driving sediment and salinity loads in the Price-San Rafael River Basin of the upper Colorado River. A Walnut Gulch rainfall simulator was operated with a variety of slope angles and rainfall intensities at two field sites (Price, Dry-X) near Price, Utah in order to evaluate how the amount and spatial distribution of vegetation affects salinity in runoff. For each simulated rainfall event, the time-varying concentrations of major cations, anions, and sediment in runoff were measured. Principal component analysis revealed that the two field sites are generally different in runoff water chemistry and soil chemistry, likely due to the difference in parent material and soil indicative of their location on different geologic members. The Dry-X site also has substantially greater total dissolved solids (TDS) and sediment in runoff, soil sodium absorption ratio (SAR), and soil cation exchange capacity (CEC) than the Price site. Despite these differences, a consistent positive linear relationship between the plot-averaged sediment and TDS concentration was found across both sites. The Rangeland Hydrology Erosion Model (RHEM) was calibrated to provide unbiased estimates of sediment in runoff from 23 runs of the rainfall simulator. RHEM simulated the plot-plot variability best at Dry-X compared to Price. Sensitivity analysis of the RHEM input parameters showed that the splash and sheet erodibility coefficient (Kss) and the effective saturated conductivity coefficient (Ke) had the largest influence on the model’s sediment and discharge outputs, respectively. The regression that predicted TDS concentration from sediment was applied to RHEM outputs to show that the model could be used to provide salinity estimates for different storm intensities on this part of the Mancos Shale. The potential influence of vegetation canopy cover on sediment production from these two sites was inferred by running RHEM with canopy cover values ranging from 0% to 100%. This changed sediment output by 111% to -91% relative to the present vegetation cover. Measures of the geometry of soil and vegetation patches at Dry-X, such as fractal dimension index and proximity index, showed a relationship to error residuals from RHEM. As the vegetation becomes less isolated, more uniform, and the tortuosity of the bare soil area increases, observed sediment decreases relative to RHEM predictions. The results of this study will help land management agencies assess the feasibility of mitigation strategies for reducing sediment and salinity loads from the saline and sodic soils of the Mancos Shale formation and indicate a possible benefit to incorporating the parameters that describe the spatial pattern of vegetation in RHEM.

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Josko, Troselj. "FLUVIAL INFLUENCE ON ESTUARINE SEDIMENT TRANSPORT PROCESSES AND LINKAGE OF ITS OUTFLOW DATA TO COASTAL MODELING". Kyoto University, 2016. http://hdl.handle.net/2433/217745.

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Zaghmouri, Imen. "Impact des fluctuations de salinité sur le cycle de l'azote dans les sédiments de l'étang de berre". Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4007/document.

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Dans l'étang de Berre, les apports excessifs en eau douce entraînent souvent des variations brusques de la salinité et des apports en azote parfois abondants. Les processus de régénération sédimentaire et d'élimination d'azote constituent des phénomènes majeurs pouvant expliquer le développement phytoplanctoniques et contrôler l'eutrophisation. L'étude de ces processus a été réalisée dans 2 stations ayant subi des historiques de variations de salinité différents. RDNA et anammox étaient négligeables. La dénitrification (couplée à la nitrification) serait le principal processus de sortie de N2 de l'étang. La forte production primaire pélagique utilisant l'ammonium a pu être expliquée par les processus de régénération, contrairement au nitrate dont la demande pélagique serait soutenue par des apports externes. Comme la salinité est susceptible d'influencer les processus d'azote, des microcosmes ont été utilisés afin d'évaluer la sensibilité de ces processus (résistance, résilience, shift) face aux variations à court terme de la salinité. Les 2 stations ont présenté des réponses différentes (dénitrification et nitrate réduction plus résilientes que la nitrification), suggérant que les stress halins à long terme influencent les réponses à court terme. Une hypothèse serait que la diversité et la structure des communautés joueraient un rôle crucial dans le maintien des taux d'activité. Dans cette étude, seule la communauté nitrifiante (AO) a été étudiée. Les AO et leurs transcrits étaient spécifiques aux sites et leurs abondances changeaient faiblement entre les microcosmes (résistance plus forte dans le site fréquemment soumis à des fluctuations de salinité)
The Berre lagoon receives excess freshwater leading to strong changes in the ecosystem salinity and in the nutrient inputs. Regeneration processes and the N2 removal of nitrogen are of a particular interest as they can explain the planktonic development and control the eutrophication state. These processes were studied in 2 stations with different patterns of long term stresses. DNRA and anammox were negligible. Denitrification (particularly the one coupled to nitrification) would be the main N2 removal in the lagoon. The high primary production based on N-NH4+ can be explained by the regeneration processes, while the primary production based on N-NO3- might be sustained by external inputs. As salinity susceptible to influence directly or indirectly the nitrogen processes, a microcosm approach was used in order to assess their sensitivity (resistance, resilience, shifts) to short term salinity fluctuations. Overall, towards the same kind of perturbations, the two stations responded differently (denitrification and nitrate reduction exhibited showed higher resilience than nitrification.), suggesting that long-term saline stresses would influence short-term responses. We suggest that the diversity and the structure of the communities would be crucial in their functional redundancy and thereby in the maintenance of the rates. In this study, we focused on the total structure of the nitrifying community (AO). AO and their transcripts were site-specific and their abundances changed slightly between microcosms (higher resistance in the site subject to frequent salinity fluctuations compared to the other site which is not affected by changes in the in situ salinity)
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Benaouda, Abdelkader. "Dynamique saisonnière des sédiments en suspension dans l'estuaire de la Gironde : modélisation opérationnelle de la réponse aux forçages hydrodynamiques". Thesis, Bordeaux 1, 2008. http://www.theses.fr/2008BOR13618/document.

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L’objectif de ce travail est d’étudier la dynamique du bouchon vaseux, ainsi que la dynamique saline, dans l’estuaire de la Gironde. La stratégie adoptée consiste à examiner, par le biais du modèle de simulation SIAM-3D, l’impact du paramétrage hydro-sédimentaire, du débit fluvial et de la bathymétrie, sur le comportement des sédiments et sur l’évolution de la salinité. L’effet de la vitesse de chute sur la dynamique sédimentaire est l’un des cas étudiés ; son impact sur la distribution des suspensions est considérable. Ainsi, la diminution de ce paramètre entraîne l’homogénéisation de la concentration sur la verticale, mais aussi l’étalement du bouchon vaseux et l’évacuation d’une masse de sédiment hors de l’estuaire. Nous avons également mis en évidence lors d’une période de débits moyens ou faibles précédée par une crue, la partition du bouchon vaseux simulé en deux masses turbides, l’une remonte l’estuaire alors que l’autre se maintient en aval. La dynamique saline a été étudiée, entre autres, par l’analyse des gradients de salinité, calculés dans l’estuaire aval et en situation de forts débits. On observe, la diminution de ces gradients avec l’augmentation de l’intensité de la marée à l’échelle des cycles vives-eaux/mortes-eaux, toutefois, de fortes valeurs sont maintenues lors de la phase d’augmentation de cette grandeur à l’échelle de la marée. D’autres résultats ont permis de vérifier la capacité du modèle à simuler des dynamiques sédimentaires observées in-situ ; on peut citer entre autres, le détachement du bouchon vaseux de la rive gauche dans l’estuaire aval et son transfert vers la rive droite, en situation de forts débits. Afin d’évaluer l’impact de l’évolution du fond des fleuves de 1959 à 2002 sur l’hydrodynamique et les dynamiques sédimentaire et saline, nous avons comparé deux simulations, l’une effectuée avec l’ancienne bathymétrie de 1959, l’autre avec la nouvelle bathymétrie de 2002. Les résultats montrent l’augmentation de la masse sédimentaire dans les fleuves avec la bathymétrie de 2002 comparée à celle de 1959, ainsi que la hausse de la salinité dans la Garonne et l’amplification de la marée dans la Dordogne. Ces résultats sont en accord avec les mesures et observations in-situ
The aim of this work is to study the turbidity maximum dynamics as well as the salinity dynamics in the Gironde estuary. The adopted strategy consists in analysing, by means of the SIAM-3D simulation model, the impact of hydro-sedimentary parameters, the fluvial flow and the bathymetry on sediment behaviour and salinity evolution. The effect of settling velocity on sediment dynamics is one of the studied cases; its impact on suspended sediment distribution is goodly. Thus, the diminution of this parameter leads to homogenisation of concentration in water column, but also spreading the turbidity maximum and evacuation of a sediment mass outside the Gironde estuary. We gave also prominence to the division of the turbidity maximum into two parts during low or mean water flow preceded by peak high water discharge, one of the parts migrates upstream whereas the other remains downstream. We studied the salinity dynamics, among others things, by means of analysing the calculated salinity gradients in the lower estuary during high water discharge. We observe the decrease of these gradients with increase of the tide intensity on a scale of spring tides/neap tides cycles, however, on a scale of tide, these gradients reach high values during the augmentation phase. Others results indicate the model capacity to simulate in-situ observations of the sediment dynamics; for example, the detachment of turbidity maximum from the left bank in the lower estuary and its transfer to the right bank during high water discharge. In order to evaluate the impact of the bed river evolution from 1959 to 2002 on hydrodynamics, sediment and salinity dynamics, we compared two simulations performed using the former (1959) and recent (2002) bathymetries. The results demonstrate that the sediment mass increase in the rivers with recent bathymetry, as well as, the salinity in the Garonne river and the tide amplitude in the Dordogne river. These results are in accordance with the in-situ measures and observations
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Gao, Chan. "Devenir des substances per et poly-fluoroalkylées (PFAS) dans les estuaires : focus sur les interactions avec les sédiments en suspension". Electronic Thesis or Diss., Bordeaux, 2024. http://www.theses.fr/2024BORD0409.

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Les substances per et poly-fluoroalkylées (PFAS) constituent un vaste groupe hétérogène de micropolluants émergents. Du fait de leur structure physico-chimique très stable, les PFAS sont persistantes et largement répandues dans l'environnement et posent de nombreux problèmes environnementaux. Ces dernières années, le devenir des PFAS a fait l'objet d'une attention croissante. Dans le cycle des PFAS, l'air, l'eau, le sol et les sédiments sont différents compartiments impliqués. À l'exutoire des grands bassins versants et à l’interface terre-mer, les estuaires sont considérés comme la principale voie d’entrée des PFAS vers le milieu océanique, puits ultime des PFAS. Les conditions estuariennes complexes affectent le comportement des PFAS dans les sédiments et déterminent le sort final des PFAS. Les estuaires jouent par ailleurs un rôle écologique majeur et sont soumis à une forte pression chimique, générant des risques environnementaux. Il est donc important d'étudier le devenir des PFAS dans les estuaires.Les sédiments estuariens constituent un réservoir important pour les PFAS, où la sorption et la désorption se produisent et contrôlent la distribution des PFAS. Les conditions géochimiques jouent un rôle essentiel dans ce processus. D'une part, les flux fluviaux apportent d'énormes quantités de particules en suspension qui absorbent les PFAS et se déposent finalement dans les sédiments estuariens. D'autre part, au cours des cycles de marée, les particules sont remises en suspension, transportées et remises en place, désorbant ou réabsorbant les PFAS. La distribution des PFAS entre les particules et l'eau est la clé de l'étude du devenir des PFAS dans les estuaires. Les conditions contrastées de salinité et de turbidité des estuaires peuvent influencer la distribution des PFAS entre les particules et l'eau en facilitant ou en entravant la sorption/désorption, ce qui complique l'interaction entre les sédiments et l'eau pour les PFAS. Il est donc très important de réaliser des études approfondies sur la distribution des PFAS entre les particules et l'eau dans les conditions estuariennes.Ces travaux sont divisés en deux parties : 1) détermination des cinétiques d'adsorption et de désorption des PFAS seuls ou mélange (compétition) sur un substrat modèle, la kaolinite et 2) étudier l'influence de la salinité et de la turbidité sur la distribution particules-eau des PFAS en conditions estuariennes. Ces travaux fournissent des éléments importants pour paramétrer les modèles de devenir des PFAS et estimer les bilans de masse à l'interface terre-mer
To understand the fate of legacy and emerging PFAS at the land-sea interface, this work focused on the interactions with estuarine sediments. More precisely, we mainly studied the influence of co-existing PFAS, salinity (S) and suspended particulate matter (SPM) on the sediment-water partitioning of PFAS. First, to investigate the effect of coexisting PFAS on their adsorption and desorption, competitive adsorption and desorption experiments were conducted using single and mixed PFAS solutions at low concentrations, using kaolinite as model sorbent. Selected PFAS include eight perfluoroalkyl carboxylates (PFCAs), two perfluoroalkyl sulfonic acids (PFSAs) and one zwitterionic PFAS (8:2 fluorotelomer sulfonamide alkylbetaine (8:2 FTAB)), which were studied in three single-solute solutions and two mixture solutions. A pseudo-second-order kinetic model was used to fit in the adsorption and desorption kinetics data correctly. Their sorption and desorption on kaolinite were quite fast, with equilibrium reached within 2h. Sorption processes appeared to be influenced by the PFAS molecular structure: sorption increased and desorption decreased with increasing fluoroalkyl chain length, characterized by the increase of log Kd. Besides, PFSAs (i.e, PFHxS and PFOS) had greater sorption and weaker desorption than PFCAs (i.e, PFHpA and PFNA) with similar fluoroalkyl chain. The zwitterionic 8:2 FTAB showed stronger sorption and smaller desorption than anions (i.e., PFOS or PFNA) with a similar fluoroalkyl chain. Sorption and desorption data obtained for single and multi-solute experiments indicated that there was no significant statistical difference between such conditions. Thus, the influence of competitive adsorption and desorption was negligible at low concentrations. To study the influence of salinity and SPM on the sorption of PFAS, we used a sediment sample collected in the fluvial sector of the Garonne-Gironde system. We performed sorption kinetics and sorption isotherms tests for the same PFAS, under 35 combination of salinity and turbidity. Based on response surface methodology (RSM) modelling approach, results indicated the sorption kinetics of PFAS onto sediment can be described by pseudo-second-order model and 24h is the equilibrium time for targeted PFAS. Besides, PFAS sorption can be well fitted by linear model and Freundlich model, the linear sorption range for PFAS studied was in the range of 0.12 to 1.31 nM (equilibrium concentration). Moreover, based on RSM modelling approach, we found that Kd varied between 0.62 and 55271 L/kg and that both S and SPM were significant factors, i.e. the Kd of PFAS was positively related to S due to salting-out effect while it was negatively related to SPM concentration. Moreover, SPM had a stronger effect than salinity (S) for PFHxA and PFHpA, whereas S was the more dominant factor for most other compounds. For PFUnDA and 8:2 FTAB, S and SPM displayed nearly equivalent weights as drivers of Kd. In addition, a negative interaction between both factors was observed, i.e. if SPM increases, the effect of S on Kd is weaker. Overall, this work provides original results to model the sorption of legacy and emerging PFAS on estuarine sediments based on RSM modelling approach. It provides a new perspective to investigate the fate of PFAS at the land-sea interface
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Libri sul tema "Sediment salinity"

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D, Boon John, Virginia. Dept. of Transportation. e Virginia Institute of Marine Science., a cura di. Three dimensional hydrodynamic-sedimentation modeling study: Hampton Roads Crossing, Lower James River, Virginia : a report to the Virginia Department of Transportation. Gloucester Point, Va: Virginia Institute of Marine Science, Dept. of Physical Science, 1999.

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T, Yost Brian, Geological Survey (U.S.), California. Dept. of Water Resources. e California. State Water Resources Control Board., a cura di. Description of salinity, temperature, chlorophyll, suspended-sediment, and velocity data, south San Francisco Bay, California, February-April 1987. Sacramento, Calif: U.S. Geological Survey, 1990.

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T, Yost Brian, Geological Survey (U.S.), California. Dept. of Water Resources e California. State Water Resources Control Board, a cura di. Description of salinity, temperature, chlorophyll, suspended-sediment, and velocity data, south San Francisco Bay, California, February-April 1987. Sacramento, Calif: U.S. Geological Survey, 1990.

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Rogowski, David. Saltwater intrusion in Salmon Bay and Lake Union sediments. [Olympia, Wash.]: Washington State Dept. of Ecology, 2000.

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Riedel-Lorjé, Jeannette Cornelie. Salzgehalts- und Trübstoffverhältnisse in dem oberen Brackwassergebiet der Elbe. [Hamburg]: Wassergütestelle Elbe, 1992.

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Baldys, S. Effects of low-flow diversions from the South Wichita River on downstream salinity of the South Wichita River, Lake Kemp, and the Wichita River, north Texas, October 1982-September 1992. Austin, Tex: U.S. Dept. of the Interior, U.S. Geological Survey, 1996.

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Baldys, S. Effects of low-flow diversions from the South Wichita River on downstream salinity of the South Wichita River, Lake Kemp, and the Wichita River, north Texas, October 1982-September 1992. Austin, Tex: U.S. Geological Survey, 1996.

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S, Baldys. Effects of low-flow diversions from the South Wichita River on downstream salinity of the South Wichita River, Lake Kemp, and the Wichita River, north Texas, October 1982-September 1992. Austin, Tex: U.S. Dept. of the Interior, U.S. Geological Survey, 1996.

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Baldys, S. Effects of low-flow diversions from the South Wichita River on downstream salinity of the South Wichita River, Lake Kemp, and the Wichita River, north Texas, October 1982-September 1992. Austin, Tex: U.S. Dept. of the Interior, U.S. Geological Survey, 1996.

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S, Baldys. Effects of low-flow diversions from the South Wichita River on downstream salinity of the South Wichita River, Lake Kemp, and the Wichita River, north Texas, October 1982-September 1992. Austin, Tex: U.S. Geological Survey, 1996.

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Capitoli di libri sul tema "Sediment salinity"

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Calmano, W., W. Ahlf e J. C. Bening. "Chemical mobility and bioavailability of sediment-bound heavy metals influenced by salinity". In Sediment/Water Interactions, 605–10. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2783-7_53.

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Hay, William W., Christopher N. Wold, Emanuel Söding e Sascha Floegel. "Evolution of Sediment Fluxes and Ocean Salinity". In Geologic Modeling and Simulation, 153–67. Boston, MA: Springer US, 2001. http://dx.doi.org/10.1007/978-1-4615-1359-9_9.

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Douglas, Audrey R., Paul A. Montagna e Timothy Dellapenna. "Influence of Inflows on Estuary Sediments". In Estuaries of the World, 173–90. Cham: Springer Nature Switzerland, 2025. https://doi.org/10.1007/978-3-031-70882-4_6.

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AbstractRivers deliver sediments, organic matter/carbon, contaminants, and nutrients from watersheds. Sediments form delta, estuarine, marsh, and wetland habitats. Most of the sediments are derived from weathered rocks that are transported by rivers during floods as both bedload (sand and gravel) and suspended load (silts and clays, i.e., mud). Siliciclastic sand can enter the estuary naturally through four mechanisms, which are: (1) shoreline erosion; (2) inflow from rivers; (3) advection into the bay via the flood tide, through tidal inlets and cuts; and (4) barrier island overwash. River-mouth/saltwater wedge dynamics trap the bedload (coarse fraction) within bayhead deltas of estuaries, with only the suspended load (mud fraction) being delivered to the estuaries under most conditions. Sand entering the bay through the tidal inlets/cuts, are trapped in the flood tidal delta proximal to the bay mouth. Barrier island overwash sands are also trapped proximal to the overwash sites. As a result, the interior of most estuarine sediment is muddy, with sandy shorelines, shoreline shoals, bayhead, and flood tidal deltas. Carbonate sands also form in situ by the abrasion of shells, most notably, oyster shells, forming shell shoals and oyster reef. Over time, the greatest “natural” changes to sediment distribution within estuaries are caused by extreme storms and floods that can deliver the equivalent of decades worth of “average fluvial sediment load” to bays within a few days. Additionally, sediment distributions and loads within estuaries can be altered by anthropogenic activities, including dredging and formation of dredge spoil island, formation of mitigation oyster reefs and wetlands, alterations in shoreline protection, and alteration of bay configurations and size. The carbon content of sediments increases with decreasing inflow and increasing salinity across the state where Sabine Lake averages 1% and Laguna Madre averages 2.5%. The nitrogen content of sediments is generally low, always <0.1%, but can be as high as 0.25% in Laguna Madre. Sedimentation rates generally range from 0.07 to 2.2 cm year−1. There has been sediment compaction and subsidence over time.
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Ahlf, Wolfgang, Wolfgang Calmano e Ulrich Förstner. "The Effects of Sediment-Bound Heavy Metals on Algae and Importance of Salinity". In Sediments and Water Interactions, 319–24. New York, NY: Springer New York, 1986. http://dx.doi.org/10.1007/978-1-4612-4932-0_26.

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Montagna, Paul A., Richard D. Kalke e Larry J. Hyde. "Effect of Freshwater Inflow on Benthic Infauna". In Estuaries of the World, 259–93. Cham: Springer Nature Switzerland, 2025. https://doi.org/10.1007/978-3-031-70882-4_11.

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AbstractBenthic organisms are ideal bioindicators of freshwater inflow effects in bays and estuaries because they are fixed in space and integrate ephemeral processes in the overlying water column over long periods of time. Freshwater inflow regulates water quality, which drives benthic abundance, productivity, diversity, and community structure. Texas estuaries have different long-term characteristic fauna that reflect the long-term average salinity and sediment conditions in each bay system. Within estuary systems, the secondary bays have distinct communities compared to the primary bays because secondary bays are closer to freshwater inflow sources and are more oligohaline and/or brackish in nature than primary bays that are more marine influenced. Similar responses occur within bay types over time when conditions change with droughts, floods, freezes, and major events, such as hurricanes. Bioindicators of freshwater inflow effects include four dominant species: the polychaetes, Mediomastus ambiseta, and Streblospio benedicti; the bivalve Mulinia lateralis; and the amphipod Ampelisca abdita. Each of these species is primarily found in secondary bays with similar salinities where abundances are higher than in primary bays. Because of the relationship between prevailing salinity conditions and benthos community structure, assessment of benthic conditions can be used to determine if a “sound ecological environment” exists in a given bay system.
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Walther, Régis, e Eric David. "3D Modeling of Salinity and Sediment Suspension in the Loire Estuary: Coupling of Processes". In Practical Applications in Engineering, 231–43. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2013. http://dx.doi.org/10.1002/9781118557792.ch21.

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Uncles, R. J., R. C. A. Elliott, S. A. Weston, D. A. Pilgrim, D. R. Ackroyd, D. J. McMillan e N. M. Lynn. "Synoptic observations of salinity, suspended sediment and vertical current structure in a partly mixed estuary". In Physics of Shallow Estuaries and Bays, 58–70. Washington, D. C.: American Geophysical Union, 1986. http://dx.doi.org/10.1029/ln016p0058.

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Clavero, V., J. A. Fernández e F. X. Niell. "Influence of salinity on the concentration and rate of interchange of dissolved phosphate between water and sediment in Fuente Piedra lagoon (S. Spain)". In Saline Lakes, 91–97. Dordrecht: Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-009-0603-7_8.

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Barua, Prabal, Anisa Mitra e Mazharul Islam. "Effect of Salinity Intrusion on Sediments in Paddy Fields and Farmers’ Adaptation Initiative: A Case Study". In Global Agricultural Production: Resilience to Climate Change, 587–609. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-14973-3_21.

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Eng, George, Xueqing Song e Leopold May. "Use of Mössbauer spectroscopy to determine the effect of salinity on the speciation of triorganotins in Anacostia River sediments". In NASSAU 2006, 117–25. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-71127-8_13.

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Atti di convegni sul tema "Sediment salinity"

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Dai, Qian, Hongxian Shan, Yonggang Jia, Xiangmei Meng, Honglei Li e Wenlin Cui. "Laboratory Study on the Relationships Between Suspended Sediment Concentration and Electrical Conductivity". In ASME 2009 28th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/omae2009-79211.

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In order to find a simple, continuous method to determine the suspended sediment concentration in a high turbidity region, experiments were conducted to look for relationships between suspended sediment concentration and electrical conductivity. Sediments were sampled from the Yellow River Delta and a conductivity sensor was used to measure the electrical conductivity of different sediment content seawater. The influencing factors such as temperature and salinity are also investigated. The results show that good linear relationships exist between suspended sediment concentration and electrical conductivity; salinity and temperature have some influence on electrical conductivity, and salinity is the most important influencing factor and temperature takes the second place. Basically, the general linear regression formulas between suspended sediment concentration and electrical conductivity can be drawn with variable salinity and temperature. The relationships suggest that it is feasible to measure suspended sediment concentration in situ using electrical conductivity sensors.
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Osadchiev, Alexander, Alexander Osadchiev, Peter Zavialov, Peter Zavialov, Vadim Pelevin e Vadim Pelevin. "METHOD FOR QUANTIFYING ADVECTION, TURBULENT MIXING, AND GRAVITATIONAL SETTLING OF RIVER-BORNE SUSPENDED SEDIMENTS IN COASTAL AREAS FROM THERMOHALINE AND OPTICAL MEASUREMENTS". In Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.31519/conferencearticle_5b1b94a309e5c6.22106638.

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This work presents an original method for quantifying advection and turbulent mixing of river-borne suspended sediments. The main idea of the method consists in joint analysis of surface distributions of salinity and sediment concentration in coastal areas influenced by river discharge. Basing on the Lagrangian approach we represent a river plume as a set of individual water particles, which inflow from a river mouth, mix with ambient sea water during their motion within a river plume and finally dissipate. Surface salinity and sediment concentration of a particle provides information about its turbulent mixing with undelaying ambient sea waters and gravitational settling of its sediments respectively during the period from its origin in the river estuary till the moment of measurement. Using these integrated Lagrangian characteristics calculated for the whole study area we reconstruct advection streamlines within the river plume and ratio between turbulent mixing and gravitational settling of river-borne suspended sediments. This method was applied to coastal areas situated in the north-eastern part of the Black Sea and the western part of the Philippine Sea. High resolution thermohaline and sediment concentration data were collected using a pump-through system equipped by a CTD instrument and a turbidity sensor.
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3

Osadchiev, Alexander, Alexander Osadchiev, Peter Zavialov, Peter Zavialov, Vadim Pelevin e Vadim Pelevin. "METHOD FOR QUANTIFYING ADVECTION, TURBULENT MIXING, AND GRAVITATIONAL SETTLING OF RIVER-BORNE SUSPENDED SEDIMENTS IN COASTAL AREAS FROM THERMOHALINE AND OPTICAL MEASUREMENTS". In Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.21610/conferencearticle_58b431548658b.

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Abstract (sommario):
This work presents an original method for quantifying advection and turbulent mixing of river-borne suspended sediments. The main idea of the method consists in joint analysis of surface distributions of salinity and sediment concentration in coastal areas influenced by river discharge. Basing on the Lagrangian approach we represent a river plume as a set of individual water particles, which inflow from a river mouth, mix with ambient sea water during their motion within a river plume and finally dissipate. Surface salinity and sediment concentration of a particle provides information about its turbulent mixing with undelaying ambient sea waters and gravitational settling of its sediments respectively during the period from its origin in the river estuary till the moment of measurement. Using these integrated Lagrangian characteristics calculated for the whole study area we reconstruct advection streamlines within the river plume and ratio between turbulent mixing and gravitational settling of river-borne suspended sediments. This method was applied to coastal areas situated in the north-eastern part of the Black Sea and the western part of the Philippine Sea. High resolution thermohaline and sediment concentration data were collected using a pump-through system equipped by a CTD instrument and a turbidity sensor.
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4

Han, Xiao, e Ning Zhang. "Coastal Hydrodynamic and Sediment-Salinity Transport Simulations for Southwest Louisiana Using Measured Vegetation Data". In ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-51571.

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Storm-surge flood is a major thread to the inhabitants and the health of the marshes in Southwest Louisiana. The floods caused direct damages to the area, but also indirectly caused excessive sedimentations in the water system, especially in Calcasieu Ship Channel which is a vital industrial water way connecting the City of Lake Charles to the Gulf. It is well known that coastal wetlands and marshes have significant impacts on the prevention and reduction of coastal floods. The wetland vegetation creates larger frictions to the flooding water and acts as the first line of defense against any storm surge floods. In this study, we center Calcasieu Ship Channel, and hydrodynamic and sediment transport simulations were conducted for Calcasieu Ship Channel and surrounding areas. The target area ranges from the city of Lake Charles as the north end and the Gulf of Mexico as the south end, and includes three connected water systems, Calcaiseu Lake, Prien Lake and Lake Charles. The entire Calcasieu Ship Channel running from north to south is included in the domain along with the Gulf Intracoastal Waterway (GIWW) in east and west directions. In authors’ previous study, only the area of south portion of the ship channel, Calcasieu Lake and its surrounding wetlands was simulated and studied. This study is a major upgrade to the model, which provides more complete understanding of the flow and sediment transport in the entire area, as well as the interactions among all water systems surrounding the ship channel. There are wetlands (two National Wild Life Refuges, one in the west and one in the east) surrounding Calcaiseu Lake, while there are various of vegetated and non-vegetated areas surrounding Prien Lake and Lake Charles. The standard 2-D depth averaged shallow water solver was utilized for the simulation of the flow phase and a standard Eulerian scalar transport equation was solved for the sediment and salinity phases. In the sediment phase, the sediment deposition and re-suspension effects are included, while in the salinity phase, the precipitation and evaporation are included. A realistic vegetation model was implemented to represent various types of vegetation coverage in the target area, and appropriate friction values were assigned to different non-vegetated areas. Measured and observed vegetation data were utilized. A coastal storm surge flood was simulated, and effects of vegetation on flood reduction and sediment distribution were investigated. The total flooded area, the flood speed, and the distribution of the flooding water and sediments were compared between vegetated and non-vegetated areas to show the differences between different types of surfaces.
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5

Liu, Wei, Runhao Chen, Xiaohui Liang, Haifeng Zhou, Dapeng Zou e Zhiwei Shi. "Design of Depth Measurement System for Seafloor Sediment Temperature and Salinity". In 2023 IEEE 16th International Conference on Electronic Measurement & Instruments (ICEMI). IEEE, 2023. http://dx.doi.org/10.1109/icemi59194.2023.10270379.

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6

Schindler, Rob, Sean Comber e Andrew Manning. "METAL POLLUTANT PATHWAYS IN COHESIVE COASTAL CATCHMENTS: INFLUENCE OF FLOCCULATION ON PARTITIONING AND FLUX". In GEOLINKS International Conference. SAIMA Consult Ltd, 2020. http://dx.doi.org/10.32008/geolinks2020/b2/v2/09.

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Potentially toxic metals (PTMs) dispersed within catchments from land-based sources pose serious, long-term threats to aquatic ecology and human health. Their chemical state or form affects the potential for transportation and bioavailability and ultimate environmental fate. PTMs are transported either as (1) particulates adsorbed onto sediments, or 2) solutes in groundwater and open channel flow. Cohesive sediment occupies a major part of the world’s coastlines. PTMs are readily sorbed onto clay/silt and consequently particulate-borne PTMs dominate in estuaries and coastal waters. Sediments also represent a considerable ‘sink’ of contaminants which can be periodically remobilized. The role of suspended particulates in the uptake, release, and transport of heavy metals is thus a crucial link in understanding PTM dispersion in these environments. Cohesive sediment is subject to flocculation which dictates the behaviour of suspended sediment. PTM partitioning, flocculation and particulate-borne PTM dynamics are spatially and temporally variable in response to a complex array of inter-related physical and chemical factors exhibited within tidal catchments. However, knowledge of the dispersion and accumulation of both particulate and soluble forms of PTMs within cohesive coastal catchments is limited by little understanding of the association of PTMs with flocculated sediments and their subsequent deposition. This study investigates the influence of changing hydrodynamics and salinities to reveal the partitioning coefficients (Kp) and PTM settling flux (PTMSF) for different spatial and temporal locations within an idealized mesotidal catchment. The data show that the ratio of soluble and particulate-borne PTMs are dependent on salinity and flocculation, and that PTMSF is dependent upon partitioning and flocculation dynamics. Kp is largely dictated by salinity, but floc size and suspended particulate matter concentration (SPMC) are also influential, particular for PTMs with low chloride complexation and in freshwater. PTMSF is a function of Kp, floc size and settling velocity and varies by up to 3 orders of magnitude in response to changing environmental conditions. Findings will improve our ability to predict and monitor contaminant transport for PTMs generated by industries such as agriculture, mining, fisheries, aquaculture & marine engineers. They can be incorporated in existing decision making tools, and help improve numerical modelling parameteristion, to maintain environmental quality standards and limit the impacts of bioavailability of metals in aquatic environment.
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7

Barber, Donald. "CARBON IN SALT MARSH SEDIMENT ACROSS ESTUARINE SALINITY AND TIDAL GRADIENTS, NORTH CAROLINA, USA". In GSA Connects 2024 Meeting in Anaheim, California. Geological Society of America, 2024. http://dx.doi.org/10.1130/abs/2024am-405418.

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8

Xiong, Chuanfang, Hongxian Shan, Shaotong Zhang, Chaoqi Zhu e Yonggang Jia. "Study on the sediment consolidation process under different salinity fields in the Yellow River Estuary". In 2017 6th International Conference on Energy, Environment and Sustainable Development (ICEESD 2017). Paris, France: Atlantis Press, 2017. http://dx.doi.org/10.2991/iceesd-17.2017.13.

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9

Chao, Xiaobo, e Yafei Jia. "Numerical Modeling of Flow, Sediment, and Salinity in Lake Pontchartrain during the Bonnet Carré Spillway Flood Release". In World Environmental and Water Resources Congress 2020. Reston, VA: American Society of Civil Engineers, 2020. http://dx.doi.org/10.1061/9780784482971.015.

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10

Zhu, Yuliang, Chencheng Xu e Xiaoyan Wei. "Impacts of Waterway Regulation Engineering on Saltwater Intrusion in the Modaomen Estuary". In ASME 2012 31st International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/omae2012-83741.

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Abstract (sommario):
A large-scale waterway regulation project, which is the main approach for people to manage coastal and estuary area will be imperative due to the high-speed economic development in Guangdong Province. The project will change the topography in the estuary region and influence the hydrodynamic conditions there. The Modaomen waterway, as the main access to the sea of Xijiang River, plays a key role in connecting outer sea. During recent years, a remarkable deterioration of tide intrusion occurred resulting in negative effect on water resource utilization in industry, agriculture and local people’s lives and therefore it is of great significance to study on the tide intrusion caused by dredging project. This paper analyses measured Modaomen hydrological data and exhibits the temporal and spatial distribution of salinity and characteristics of fresh and salinity water mixing, as well as the correlation between salinity, water level and suspended sediment concentration in the Modaomen region. Based on the establishment of high-precision three-dimensional salinity mathematical model in Modaomen region, this paper calculates various engineering plans and examines the changes of flow field and tidal saltwater intrusion, which provides elementary base for implementation of the waterway regulation engineering. During the process of calculation, the terrain, the border and validation data that adopted in this paper is relatively new and have high reliability. The study indicates that the salinity degree has a merely minor increase after projects indeed in the estuary to provide situation for tide intrusion. However, the influence is little and it fails to be the chief reasons responsible for the depravation of tide intrusion in the Modaomen estuary recent years.
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Rapporti di organizzazioni sul tema "Sediment salinity"

1

McAlpin, Jennifer, e Cassandra Ross. Houston Ship Channel numerical model update and validation. Engineer Research and Development Center (U.S.), agosto 2023. http://dx.doi.org/10.21079/11681/47498.

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The Houston Ship Channel (HSC) is one of the busiest deep-draft navigation channels in the United States and must be able to accommodate increasing vessel sizes. The US Army Corps of Engineers, Galveston District (SWG), requested the US Army Engineer Research and Development Center, Coastal and Hydraulics Laboratory, update and revalidate a previously developed three-dimensional Adaptive Hydraulics (AdH) hydrodynamic and sediment model of the HSC, Galveston, and Trinity Bays. The model is necessary for analyzing potential impacts on salinity, sediment, and hydrodynamics due to alternatives designed to reduce shoaling in the HSC. SWG requested an updated validation of the previously developed AdH model of this area to calendar years 2010 and 2017, utilizing newly collected sediment data. Updated model inputs were supplied for riverine suspended sediment loads as well as for the ocean tidal boundary condition. The updated model shows good agreement to field data in most conditions but also indicates potential issues with freshwater flow inputs as well as the ocean salinity boundary condition.
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2

Brown, Gary, e Kimberly Pevey. Hydrodynamic, salinity, and morphological modeling study of a sediment diversion : an application of the Adaptive Hydraulics Model/SEDLIB Sediment Transport Library. Engineer Research and Development Center (U.S.), marzo 2019. http://dx.doi.org/10.21079/11681/32445.

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3

McAlpin, Jennifer N., e Cassandra G. Ross. Houston Ship Channel Expansion Channel Improvement Project (ECIP) Numerical Modeling Report : Increased Channel Width Analysis. Engineer Research and Development Center (U.S.), febbraio 2021. http://dx.doi.org/10.21079/11681/39739.

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Abstract (sommario):
The Houston Ship Channel is one of the busiest deep -draft navigation channels in the United States and must be able to accommodate larger vessel dimensions over time. The U.S. Army Engineer District, Galveston (SWG) requested the U.S. Army Engineer Research and Development Center, Coastal and Hydraulics Laboratory perform hydrodynamic and sediment modeling of proposed modifications along the Houston Ship Channel. The modeling results are necessary to provide data for salinity and sediment transport analysis a s well as ship simulation studies. SWG provided a project alternative that includes channel widening, deepening, and bend easing. After initial analysis, two additional channel widths in the bay portion of the Houston Ship Channel were requested for testing. The results of these additional channel widths are presented in this report. The model shows that the salinity does not vary significantly due to the channel modifications being considered for this project. Changes in salinity are 2 parts per thousand or less. The tidal prism increases by less than 2% when the project is included, and the tidal amplitudes increase by no more than 0.01 meter. The residual velocity vectors do vary in and around areas where project modifications are made.
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4

Raikow, David, Jacob Gross, Amanda McCutcheon e Anne Farahi. Trends in water quality and assessment of vegetation community structure in association with declining mangroves: A condition assessment of American Memorial Park. National Park Service, 2023. http://dx.doi.org/10.36967/2301598.

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American Memorial Park (AMME) in Saipan contains a rare mangrove wetland that is known to support several endangered species. Through monitoring water quality and vegetation characteristics of the wetland for >10 years we documented a declining mangrove population, an increase in invasive plant species, and declining surface water salinity. Comprehensive surveys conducted in 2014 and 2019 quantified declines in the plant community observed by park staff. Surface water salinity declined from 2009 to 2018 and no other trend in surface water quality was observed. Over the time period of the present study, AMME experienced shifts in annual rainfall conditions that could be associated with ENSO cycles. Dry conditions beginning in late 2016 and continuing through mid-2018 resulted in some surface water sampling sites completely drying. Several stressors may have contributed to declines in mangroves adapted to saturated soils directly and allowed competing plants to proliferate, including disruption of hydrologic connectivity with marine waters resulting in reduced surface water salinity, reduced rainfall causing dry soil conditions, and physical storm damage to canopies. Recommendations include study of groundwater salinity, maintaining or modifying a culvert subject to filling with sediment or other excavation work to improve saline water flow to the wetland at high tides, the establishment of a new groundwater monitoring well, adding a surface water monitoring station near the culvert, conducting a spatial assessment of the mangrove habitat suitability within the mangrove wetland, and developing or assisting with mangrove interpretive and outreach programs.
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5

McAlpin, Jennifer, e Cassandra Ross. Houston Ship Channel Expansion Channel Improvement Project (ECIP) numerical modeling report : BABUS cell and Bird Island analysis. Engineer Research and Development Center (U.S.), agosto 2021. http://dx.doi.org/10.21079/11681/41581.

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Abstract (sommario):
The Houston Ship Channel (HSC) is one of the busiest deep-draft navigation channels in the United States and must be able to accommodate increasing vessel sizes. The US Army Engineer District, Galveston (SWG), requested the Engineer Research and Development Center, Coastal and Hydraulics Laboratory, perform hydrodynamic and sediment modeling of proposed modifications in Galveston and Trinity Bays and along the HSC. The modeling results are necessary to provide data for hydrodynamic, salinity, and sediment transport analysis. SWG provided three project alternatives that include closing Rollover Pass, Bay Aquatic Beneficial Use System cells, Bird Islands, and HSC modifications. These alternatives and a Base (existing condition) will be simulated for present (2029) and future (2079) conditions. The results of these alternatives/conditions as compared to the Base are presented in this report. The model shows that the mean salinity varies by 2–3 ppt due to the HSC channel modifications and by approximately 5 ppt in the area of East Bay due to the closure of Rollover Pass. The tidal prism increases by 2.5% to 5% in the alternatives. The tidal amplitudes change by less than 0.01 m. The residual velocity vectors vary in and around areas where project modifications are made.
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6

Li, Honghai, Mitchell Brown, Lihwa Lin, Yan Ding, Tanya Beck, Alejandro Sanchez,, Weiming Wu, Christopher Reed e Alan Zundel. Coastal Modeling System user's manual. Engineer Research and Development Center (U.S.), aprile 2024. http://dx.doi.org/10.21079/11681/48392.

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Abstract (sommario):
The Coastal Modeling System (CMS) is a suite of coupled 2D numerical models for simulating nearshore waves, currents, water levels, sediment transport, morphology change, and salinity and temperature. Developed by the Coastal Inlets Research Program of the US Army Corps of Engineers, the CMS provides coastal engineers and scientists a PC-based, easy-to-use, accurate, and efficient tool for understanding of coastal processes and for designing and managing of coastal inlets research, navigation projects, and sediment exchange between inlets and adjacent beaches. The present technical report acts as a user guide for the CMS, which contains comprehensive information on model theory, model setup, and model features. The detailed descriptions include creation of a new project, configuration of model grid, various types of boundary conditions, representation of coastal structures, numerical methods, and coupled simulations of waves, hydrodynamics, and sediment transport. Pre- and post-model data processing and CMS modeling procedures are also described through operation within a graphic user interface—the Surface- water Modeling System.
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7

Wiggert, Jerry, Brandy Armstrong, Mustafa Kemal Cambazoglu e K. K. Sandeep. Mid-Breton Sediment Diversion (MBrSD) Assessment – Final Report. The University of Southern Mississippi, 2022. http://dx.doi.org/10.18785/sose.001.

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Abstract (sommario):
The purpose of this project is to provide managers at the Mississippi Department of Marine Resources (MDMR) with the scientific information needed to accurately address public concerns regarding the potential effects of the Louisiana Coastal Master Plan / Coastal Protection and Restoration Authority (CPRA) Mid-Breton Sediment Diversion (MBrSD) on the jurisdictional waters and resources of Mississippi. The stated design purpose of the MBrSD is to reconnect and re-establish the deltaic sediment deposition process between the Mississippi River and the Breton Sound Basin through a diversion that will deliver up to 75,000 cfs of sediment-laden freshwater. The report presented herein provides model-based guidance on the impact that the introduction of the MBrSD will have on salinity conditions in the Mississippi Sound (MSS) and Mississippi's jurisdictional waters that encompass oyster reef locations. Oysters are key ecosystem health indicators and economic drivers for the State of Mississippi and freshwater diversions into the western MS Sound (WMSS) have recently led to significant, unprecedented environmental impacts resulting in oyster mortality. The potential addition of a new pathway for additional freshwater to be introduced into the MSS requires careful assessment of the potential impacts that may be incurred. This project is designed to assess the impact of implementing the MBrSD on the physical environment in the WMSS. The primary aim is to understand the connectivity between MBrSD-derived freshwater input to Breton Sound on the environmental conditions impacting the oyster reefs of the WMSS near Bay St. Louis. A physical ocean modeling system based on the Coupled Ocean Atmosphere Wave Sediment Transport (COAWST) has been used to simulate the circulation and dynamics over the entire MSS with the analysis presented herein focusing particularly on the western to central MSS. This project demonstrates the importance of applying modeling-based scientific research and the capability of physical ocean circulation models for assessing aquatic ecosystem health, particularly in key oyster reef areas.
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Messina, Francesca, Ioannis Georgiou, Melissa Baustian, Travis Dahl, Jodi Ryder, Michael Miner e Ronald Heath. Real-time forecasting model development work plan. Engineer Research and Development Center (U.S.), settembre 2023. http://dx.doi.org/10.21079/11681/47599.

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Abstract (sommario):
The objective of the Lowermost Mississippi River Management Program is to move the nation toward more holistic management of the lower reaches of the Mississippi River through the development and use of a science-based decision-making framework. There has been substantial investment in the last decade to develop multidimensional numerical models to evaluate the Lowermost Mississippi River (LMMR) hydrodynamics, sediment transport, and salinity dynamics. The focus of this work plan is to leverage the existing scientific knowledge and models to improve holistic management of the LMMR. Specifically, this work plan proposes the development of a real-time forecasting (RTF) system for water, sediment, and selected nutrients in the LMMR. The RTF system will help inform and guide the decision-making process for operating flood-control and sediment-diversion structures. This work plan describes the primary components of the RTF system and their interactions. The work plan includes descriptions of the existing tools and numerical models that could be leveraged to develop this system together with a brief inventory of existing real-time data that could be used to validate the RTF system. A description of the tasks that would be required to develop and set up the RTF system is included together with an associated timeline.
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9

Eisemann, Eve, Catherine Thomas, Matthew Balazik, Damarys Acevedo-Mackey e Safra Altman. Environmental factors affecting coastal and estuarine submerged aquatic vegetation (SAV). Engineer Research and Development Center (U.S.), ottobre 2021. http://dx.doi.org/10.21079/11681/42185.

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Abstract (sommario):
Submerged aquatic vegetation (SAV) growing in estuarine and coastal marine systems provides crucial ecosystem functions ranging from sediment stabilization to habitat and food for specific species. SAV systems, however, are sensitive to a number of environmental factors, both anthropogenic and natural. The most common limiting factors are light limitation, water quality, and salinity, as reported widely across the literature. These factors are controlled by a number of complex processes, however, varying greatly between systems and SAV populations. This report seeks to conduct an exhaustive examination of factors influencing estuarine and coastal marine SAV habitats and find the common threads that tie these ecosystems together. Studies relating SAV habitats in the United States to a variety of factors are reviewed here, including geomorphological and bathymetric characteristics, sediment dynamics, sedimentological characteristics, and water quality, as well as hydrologic regime and weather. Tools and methods used to assess each of these important factors are also reviewed. A better understanding of fundamental environmental factors that control SAV growth will provide crucial information for coastal restoration and engineering project planning in areas populated by SAVs.
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10

Krafft, Douglas, Rachel Bain, Jack Cadigan e Richard Styles. A review of tidal embayment shoaling mechanisms in the context of future wetland placement. Engineer Research and Development Center (U.S.), dicembre 2022. http://dx.doi.org/10.21079/11681/46143.

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Abstract (sommario):
Wetland construction in tidally influenced embayments is a strategy for beneficial use of sediment dredged from nearby navigation channels. These projects have the potential to alter basin morphology, tidal hydrodynamics, and shoaling trends. This special report provides a broad review of the literature related to engineering-induced changes in tidal range, salinity, tidal prism, tidal asymmetry, and other known causes of shoaling. Each potential shoaling mechanism is then evaluated in the context of wetland placement to provide a foundation for future beneficial use research. Based on a compilation of worldwide examples, wetland placement may reduce tidal amplitude and enhance ebb current dominance, thus reducing shoaling rates in the channels. However, constructed wetlands could also reduce the embayment’s tidal prism and cause accelerated shoaling relative to the pre-engineered rate. Because constructed wetlands are often created in conjunction with navigation channel dredging, the system’s morphologic response to wetland construction is likely to be superimposed upon its response to channel deepening, and the net effect may vary depending on a variety of system-specific parameters. Planning for future wetland placements should include an evaluation of local hydrodynamic behavior considering these factors to predict site-specific response.
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