29 research outputs found

    CALCULATING BEDLOAD TRANSPORT IN RIVERS: CONCEPTS, CALCULUS ROUTINES AND APPLICATION

    Get PDF
    Rivers are immensely important to human activities such as water supply, navigation, energy generation, and agriculture. They are also an important morphodynamic agent of erosion, transport and deposition. Their capacity to transport sediment depends on their hydraulic characteristics and can be predicted by mathematical models. Several mathematical models can be used to compute bed-load transport. Each one is appropriately better for certain conditions. In this paper, we present an application built in Microsoft Excel to compute the bed-load transport in rivers based on the Van Rijn mathematical model. The Van Rijn model is appropriate for rivers transporting sandy sediments in conditions of subcritical flow. Hydraulic parameters such as channel slope, stream power, and Reynolds and Froude numbers can be calculated using the application proposed here. The application was tested in the Parana River and results from the calculations are consistent with data obtained from fieldwork surveys. The error of the application was only 20%, which shows good agreement of the model with survey values.CNPqMato Grosso do Sul Research FoundationSao Paulo Research FoundationNational Council of Technological and Scientific DevelopmentCAPESSao Paulo Research Foundation (FAPESP)Univ Estadual Paulista, Inst Geociencias & Ciencias Exatas, Ave 24A,1515, BR-13506900 Rio Claro, SP, BrazilUniv Fed Mato Grosso do Sul, Dept Geog, Ave Rio Branco 1270, BR-79304902 Corumba, MS, BrazilUniv Fed Sao Paulo, Dept Ciencias Ambientais, Rua Sao Nicolau 210, BR-09913030 Diadema, SP, BrazilUniv Kentucky, Dept Earth & Environm Sci, 101 Slone Res Bldg, Lexington, KY 40506 USAUniv Fed Sao Paulo, Dept Ciencias Ambientais, Rua Sao Nicolau 210, BR-09913030 Diadema, SP, BrazilCNPq: 140334/2015-7CNPq: 308563/2013-1CNPq: 312386/2014-1FUNDECT/CNPq: 083/2016]FAPESP: 2007/55987-3FAPESP: 2014/06889-2CNPq: 443437/2014-9CNPq: 447402/2014-5CAPES: 140334/2015-7CAPES: 308563/2013-1CAPES: 312386/2014-1FAPESP: 2014/23334-4Web of Scienc

    METHODOLOGY FOR ANALYSIS OF DISTRIBUTION AND CLASSIFICATION OF THE INTENSITY OF DEQUADA FISH KILL EVENTS IN THE PANTANAL WETLAND

    Get PDF
    Extensive fish mortality occurs occasionally in the Pantanal wetland and the phenomenon is called dequada by local inhabitants. The phenomenon originates by deterioration water quality in rivers and lakes, and the depletion of dissolved oxygen (DO) is the major indicator. Researches have shown that dequada occurs when DO reaches values lower than 3 mg/L. In addition, the duration of these low DO values determines the intensity of fish mortality. This paper presents a proposed classification of dequada event, using water quality data for Pantanal rivers surveyed by National Agency of Water (ANA). The proposed method has qualitative and quantitative bases and utilizes mean DO value and duration of these values, based on historical series of DO measurements. The results are compared to other studies of the dequada phenomenon, showing that the method is efficient to determine locales with higher probability of dequada. The Paraguay River has displayed highest dequada intensity. The rivers with narrower floodplains, such as Piquiri River, do not have dequada or the intensity is lower. The phenomenon is shown to be linked to basin hydrological condition

    CALCULATING BEDLOAD TRANSPORT IN RIVERS: CONCEPTS, CALCULUS ROUTINES AND APPLICATION

    Get PDF
    Rivers are immensely important to human activities such as water supply, navigation, energy generation, and agriculture. They are also an important morphodynamic agent of erosion, transport and deposition. Their capacity to transport sediment depends on their hydraulic characteristics and can be predicted by mathematical models. Several mathematical models can be used to compute bed-load transport. Each one is appropriately better for certain conditions. In this paper, we present an application built in Microsoft Excel to compute the bed-load transport in rivers based on the Van Rijn mathematical model. The Van Rijn model is appropriate for rivers transporting sandy sediments in conditions of subcritical flow. Hydraulic parameters such as channel slope, stream power, and Reynolds and Froude numbers can be calculated using the application proposed here. The application was tested in the Paraná River and results from the calculations are consistent with data obtained from fieldwork surveys. The error of the application was only 20%, which shows good agreement of the model with survey values

    SPATIOTEMPORAL EVOLUTION OF THE MARGINS OF LAKE UBERABA, PANTANAL FLOODPLAIN (BRAZIL)

    Get PDF
    Aquatic macrophytes are important components of wetland ecosystems, and studying them contributes to a better understanding of ecological succession in the Pantanal. The function and history of floating macrophytes on the shores of Lake Uberaba, located on the Paraguay River floodplain, were examined. A multitemporal analysis of Landsat satellite images in the years 1984-2015 was conducted. For the analysis, a land cover map was generated with three classes: water, aquatic macrophytes, and surroundings (undefined vegetation). The results revealed ~21.4% decrease in open water area of the lake over a period of 26 years (-4.7 km2/yr.). The expansion of vegetation helps explain the loss of open water and the recent shrinkage of Lake Uberaba. Macrophyte surface area along the lake margins grew by 1.4 km2/yr. Through ecological succession, the growth and decay of aquatic plants (r-strategists) along the lake shore likely provided the soil substrate needed for colonization by terrestrial plant assemblages (k-strategists). This hypothesis that we propose to describe the evolution of dynamic geomorphological processes in Lake Uberaba should be tested in other areas to verify its applicability to similar system

    Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

    Get PDF
    Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

    Catálogo Taxonômico da Fauna do Brasil: setting the baseline knowledge on the animal diversity in Brazil

    Get PDF
    The limited temporal completeness and taxonomic accuracy of species lists, made available in a traditional manner in scientific publications, has always represented a problem. These lists are invariably limited to a few taxonomic groups and do not represent up-to-date knowledge of all species and classifications. In this context, the Brazilian megadiverse fauna is no exception, and the Catálogo Taxonômico da Fauna do Brasil (CTFB) (http://fauna.jbrj.gov.br/), made public in 2015, represents a database on biodiversity anchored on a list of valid and expertly recognized scientific names of animals in Brazil. The CTFB is updated in near real time by a team of more than 800 specialists. By January 1, 2024, the CTFB compiled 133,691 nominal species, with 125,138 that were considered valid. Most of the valid species were arthropods (82.3%, with more than 102,000 species) and chordates (7.69%, with over 11,000 species). These taxa were followed by a cluster composed of Mollusca (3,567 species), Platyhelminthes (2,292 species), Annelida (1,833 species), and Nematoda (1,447 species). All remaining groups had less than 1,000 species reported in Brazil, with Cnidaria (831 species), Porifera (628 species), Rotifera (606 species), and Bryozoa (520 species) representing those with more than 500 species. Analysis of the CTFB database can facilitate and direct efforts towards the discovery of new species in Brazil, but it is also fundamental in providing the best available list of valid nominal species to users, including those in science, health, conservation efforts, and any initiative involving animals. The importance of the CTFB is evidenced by the elevated number of citations in the scientific literature in diverse areas of biology, law, anthropology, education, forensic science, and veterinary science, among others

    Geomorfologia e hidrossedimentologia da planície do Rio Paraguai, da Lagoa Vermelha à confluência do Rio Miranda, Pantanal Mato-Grossense

    No full text
    A planície do rio Paraguai ao norte da cidade de Corumbá-MS é um sistema deposicional que vem sendo construído pelo rio Paraguai desde tempos pleistocênicos. Com base em dados de sensores remotos e verificação de campo, mapeamento geomorfológico foi realizado na planície do rio Paraguai, da lagoa Vermelha à confluência do rio Miranda. Feições fluviais deposicionais foram reconhecidas na área estudada, que é composta por cinturões de meandros e rede de paleocanais na planície de inundação. Paleocinturões de meandros foram reconhecidos na planície do rio Paraguai e apresentam padrão anabranching, tendo sido reconhecidos e mapeados três paleocinturões. Os paleocinturões exibem paleoformas deposicionais que indicam condições hidrossedimentares diferentes das atuais. O cinturão de meandros atual do rio Paraguai foi subdivido em cinco trechos de acordo com a direção e a largura, e também com sinuosidade do canal que diminui de norte para sul. Com base no mapeamento e interpretação das associações de formas deposicionais reconhecidas na área, foi proposto esquema evolutivo da geomorfologia da planície. Rede de drenagem abandonada, parcialmente preservada na planície de inundação e composta por formas elevadas de canal-diques evidenciam período mais seco, provavelmente no Pleistoceno tardio. Os paleocinturões de meandros com padrão anabranching, que truncam as formas de canais-diques, são registro de mudanças paleoambientais significativas na planície do rio Paraguai, associadas a aumento da precipitação e da descarga fluvial. Com maior descarga fluvial e aporte sedimentar, o rio Paraguai passou a construir de modo agradacional, possivelmente na da transição do Pleistoceno para o Holoceno, cinturões de meandros com direção aproximada norte-sul. Com a progressiva melhora climática e aumento das vazões...The Paraguay river floodplain, north of Corumbá city, state of Mato Grosso do Sul, is a depositional system which has been built by the Paraguay river since Pleistocene. Based on remote sensing data and field verification, geomorphological mapping was accomplished for the floodplain of the Paraguay river, from Vermelha lake to the Miranda river confluence. Depositional fluvial landforms were recognized in Paraguay river floodplain, composed by abandoned meanders belts and network of paleochannels on the floodplain. Three generations of anabranching pattern abandoned meander belts were recognized in the studied area. The abandoned meanders belts have depositional landforms indicating differents hidrossedimentologycal conditions. Based on channel direction, meander belt width and channel sinuosity index that decreases from north to south, the current Paraguay river meander belt was subdivided into five reaches. Based on the mapping and interpretation of the depositional landforms associations, evolutionary outline of the geomorphology of the floodplain was proposed. Abandoned drainage network, partially preserved in the floodplain and composed by higher landforms of channel-levees, shows evidences of a drier period, probably in the Late Pleistocene. The abandoned meanders belts anabranching pattern, that truncate the landforms of channel-levees, are records of significant paleoenvironmental changes in the Paraguay river floodplain, associated to the precipitation and fluvial discharge increase. Due to higher fluvial discharge and sediment yield, the Paraguay river builded in an agradational way, possibly in the transition of Pleistocene to Holocene, meanders belts with north-south direction. With progressive climatic changes and river discharge increases, an avulsion occurred in Paraguay river nearby Castelo... (Complete abstract click electronic access below

    WATER BALANCE BASED ON REMOTE SENSING DATA IN PANTANAL

    No full text
    Water storage in a drainage basin determines its water security. The quantity of water retained in the watershed can be measured by means of the water balance calculation. This balance can be defined by the input of water subtracted from the outputs. However, for the Pantanal, the measurements of water inlet and outlet are expensive, which makes the use of remote sensing data a high impact tool with clear socioeconomic advantages. Studies of water availability with orbital sensors are relatively scarce in the Upper Paraguay Basin (BAP). This work is an attempt to estimate the BAP water balance using rainfall and evapotranspiration remote sensing data from the Tropical Rainfall Measuring Mission (TRMM) and the MODIS Global Evapotranspiration Project (MOD16), respectively. The results indicate that BAP had an annual surplus of water between 2000 and 2014, though water parameters seem weakly correlated at annual basis. However, there may be atmospheric-climatic phenomena that maximize the correlation between the hydrological parameters and the temperature anomaly with delays of 2 to 5 years, suggesting lagged teleconnections with QBO and ENSO
    corecore