Tidal Inlets Hydraulics and Morphological Modeling: An application to Mundaú Lagoon, Brazi

Tidal inlets are narrow channels connecting coastal lagoons to the sea and in this way controlling the exchange of water while serving as navigational pathways. These important components of the coast are also very dynamic environments, having their morphology determined by multiple sediment transport processes, making tidal inlets difficult to model. Expected future sea level rise imposes an added challenge to the management and maintenance of the inlets and also of the connected lagoons, in particular for poorly studied regions that often lack data to support more detailed morphological models. The present thesis advances the development of new numerical and analytical models to be used in preliminary studies and to serve as useful tools for qualitative and quantitative assessment of tidal inlet hydraulics and morphology. The study validated the developed approaches against a natural and dynamic inlet-lagoon system: the Mundaú Lagoon (northeastern Brazil). Furthermore, the research investigated internal processes of this lagoon that are affected by the flow through its inlet, such as the water exchange, during the critical dry season scenario, and the impacts of the tidal exchange on the lagoon salinity dynamics and population of its characteristic mussels. A semi-analytical approach was developed based on the classical Keulegan equations, resulting in a series of expressions in non-dimensional form, describing key characteristics of the inlet flow as the lagoon levels response to tides, tidal prism, and inlet velocities, having as the main independent variable the repletion coefficient. These flow expressions were then used in a sediment balance equation for the inlet evolution resulting in diagrams of inlet equilibrium for different scenarios related to inlet geometry configurations. The numerical model for the inlet morphology was applied in the Mundaú lagoon inlet long-term (decadal) and validated through schematic simulations and an application to a complex set of forcing conditions. In this way, the inlet evolution was estimated through the evolution of the inlet width, based on a geometrically similar idealization of the cross-section. The approach taken resulted in a satisfactory description of the inlet evolution through fast simulations and showing potential for long-term assessment of the inlet morphology. In conclusion, the developed models demonstrated the ability to reproduce the main characteristics of the inlet flow and morphological evolution, requiring only key information about the inlet and lagoon geometries as well as the main forcing. Furthermore, the fast execution times required by the numerical model is promising for applications in a probabilistic manner exploring multiple future scenario

Open-access portal with hindcast wave data for Skåne and Halland

Wave climate data for the Swedish provinces Skane and Halland, were hindcast using SWAN, a third-generation spectral wave model. The 40-year wave dataset, from 1979 to 2019, is made available through an open-access data portal (https://gis.sgi.se/vagmodell/). The wave data has a three-hour resolution and includes significant wave height, peak wave period, and wave direction. The wave model domain encompasses the Baltic Sea, Öresund, Kattegat, and Skagerrak. Along the coast of Skane and Halland, the spatial resolution of the computational nodes, from which data can be extracted in the portal, is 250 m. In the offshore areas, the resolution of the computational grid is coarser. The simulated significant wave height was validated against observations from 25 wave gauges, operating intermittently during the simulation period. The coefficient of determination, R2, for these comparisons ranged from 0.46 to 0.93 for the different stations. For 15 wave gauges, R2 values for the comparisons exceeded 0.80. The wave model will continuously be updated and developed

A STUDY ON THE WATER EXCHANGE IN MUNDAÚ LAGOON, NORTHEASTERN BRAZIL DURING THE DRY SEASON

Changes in the inlet morphology of choked coastal lagoons often restrict the water exchange with the sea, making them vulnerable to pollution release and eutrophication processes. In this study, the role of tides for the water exchange was investigated in a choked lagoon for critical scenarios during the low river flow season. Both an integrated and spatially distributed approach were employed using Lagrangian tracking of particles. The spring tides were responsible for the most pronounced water exchange and the spatially distributed approach identified different zones with similar water exchange characteristics. The tide action was primarily limited to the southern portion of the lagoon presenting a zone with rapid exchange times, whereas the other parts involved lower exchange and consequently long renewal times making it a more vulnerable area to different types of pollution releases

MORPHOLOGICAL MODELING OF TIDAL INLET EVOLUTION: AN APPLICATION TO MUNDAÚ INLET, BRAZIL

The aim of this study was to develop a morphological model for long-term inlet evolution to be applied using a minimum amount of input data and requiring low computational costs. The model was implemented numerically and then validated for a real inlet application: Mundaú inlet (northeastern Brazil), a dynamic inlet with a marked freshwater seasonality and alongshore sand transport, reduced by reef sheltering. The model performance was verified, over a total period of 11 years, comparing the simulated inlet width with Landsat and Google Earth images. The simulated inlet channel morphology presented a satisfactory agreement with observations. With the low computational costs, the developed model represented a reliable approach with demonstrated potential to be applied in the quantitative assessment of inlet evolution over long time periods

A SEMI-ANALYTIC MODEL OF TIDAL INLETS AND THEIR EVOLUTION

The water exchange between the sea and a lagoon or bay through an inlet due to tides is a classical topic that has been investigated in a large number of studies (Keulegan, 1967; O’Brien and Dean, 1972; O’Brien and Clark, 1974; Escoffier, 1977). In this paper, a simple semi-analytic model of the flow induced by tides through an inlet connecting the sea to a lagoon or bay is developed. The model is employed to derive explicit expressions for key parameters associated with inlet flows such as bay water level amplitude, tidal prism, maximum inlet velocity, and mixing (retention) time. Also, the inlet flow model is combined with a sediment transport model to determine the conditions for equilibrium as well as the evolution of the inlet cross-sectional area towards equilibrium or closure

Neotropical freshwater fisheries : A dataset of occurrence and abundance of freshwater fishes in the Neotropics

The Neotropical region hosts 4225 freshwater fish species, ranking first among the world's most diverse regions for freshwater fishes. Our NEOTROPICAL FRESHWATER FISHES data set is the first to produce a large-scale Neotropical freshwater fish inventory, covering the entire Neotropical region from Mexico and the Caribbean in the north to the southern limits in Argentina, Paraguay, Chile, and Uruguay. We compiled 185,787 distribution records, with unique georeferenced coordinates, for the 4225 species, represented by occurrence and abundance data. The number of species for the most numerous orders are as follows: Characiformes (1289), Siluriformes (1384), Cichliformes (354), Cyprinodontiformes (245), and Gymnotiformes (135). The most recorded species was the characid Astyanax fasciatus (4696 records). We registered 116,802 distribution records for native species, compared to 1802 distribution records for nonnative species. The main aim of the NEOTROPICAL FRESHWATER FISHES data set was to make these occurrence and abundance data accessible for international researchers to develop ecological and macroecological studies, from local to regional scales, with focal fish species, families, or orders. We anticipate that the NEOTROPICAL FRESHWATER FISHES data set will be valuable for studies on a wide range of ecological processes, such as trophic cascades, fishery pressure, the effects of habitat loss and fragmentation, and the impacts of species invasion and climate change. There are no copyright restrictions on the data, and please cite this data paper when using the data in publications

NEOTROPICAL CARNIVORES: a data set on carnivore distribution in the Neotropics

Mammalian carnivores are considered a key group in maintaining ecological health and can indicate potential ecological integrity in landscapes where they occur. Carnivores also hold high conservation value and their habitat requirements can guide management and conservation plans. The order Carnivora has 84 species from 8 families in the Neotropical region: Canidae; Felidae; Mephitidae; Mustelidae; Otariidae; Phocidae; Procyonidae; and Ursidae. Herein, we include published and unpublished data on native terrestrial Neotropical carnivores (Canidae; Felidae; Mephitidae; Mustelidae; Procyonidae; and Ursidae). NEOTROPICAL CARNIVORES is a publicly available data set that includes 99,605 data entries from 35,511 unique georeferenced coordinates. Detection/non-detection and quantitative data were obtained from 1818 to 2018 by researchers, governmental agencies, non-governmental organizations, and private consultants. Data were collected using several methods including camera trapping, museum collections, roadkill, line transect, and opportunistic records. Literature (peer-reviewed and grey literature) from Portuguese, Spanish and English were incorporated in this compilation. Most of the data set consists of detection data entries (n = 79,343; 79.7%) but also includes non-detection data (n = 20,262; 20.3%). Of those, 43.3% also include count data (n = 43,151). The information available in NEOTROPICAL CARNIVORES will contribute to macroecological, ecological, and conservation questions in multiple spatio-temporal perspectives. As carnivores play key roles in trophic interactions, a better understanding of their distribution and habitat requirements are essential to establish conservation management plans and safeguard the future ecological health of Neotropical ecosystems. Our data paper, combined with other large-scale data sets, has great potential to clarify species distribution and related ecological processes within the Neotropics. There are no copyright restrictions and no restriction for using data from this data paper, as long as the data paper is cited as the source of the information used. We also request that users inform us of how they intend to use the data

Evaluation of a quality improvement intervention to reduce anastomotic leak following right colectomy (EAGLE): pragmatic, batched stepped-wedge, cluster-randomized trial in 64 countries

Background Anastomotic leak affects 8 per cent of patients after right colectomy with a 10-fold increased risk of postoperative death. The EAGLE study aimed to develop and test whether an international, standardized quality improvement intervention could reduce anastomotic leaks. Methods The internationally intended protocol, iteratively co-developed by a multistage Delphi process, comprised an online educational module introducing risk stratification, an intraoperative checklist, and harmonized surgical techniques. Clusters (hospital teams) were randomized to one of three arms with varied sequences of intervention/data collection by a derived stepped-wedge batch design (at least 18 hospital teams per batch). Patients were blinded to the study allocation. Low- and middle-income country enrolment was encouraged. The primary outcome (assessed by intention to treat) was anastomotic leak rate, and subgroup analyses by module completion (at least 80 per cent of surgeons, high engagement; less than 50 per cent, low engagement) were preplanned. Results A total 355 hospital teams registered, with 332 from 64 countries (39.2 per cent low and middle income) included in the final analysis. The online modules were completed by half of the surgeons (2143 of 4411). The primary analysis included 3039 of the 3268 patients recruited (206 patients had no anastomosis and 23 were lost to follow-up), with anastomotic leaks arising before and after the intervention in 10.1 and 9.6 per cent respectively (adjusted OR 0.87, 95 per cent c.i. 0.59 to 1.30; P = 0.498). The proportion of surgeons completing the educational modules was an influence: the leak rate decreased from 12.2 per cent (61 of 500) before intervention to 5.1 per cent (24 of 473) after intervention in high-engagement centres (adjusted OR 0.36, 0.20 to 0.64; P < 0.001), but this was not observed in low-engagement hospitals (8.3 per cent (59 of 714) and 13.8 per cent (61 of 443) respectively; adjusted OR 2.09, 1.31 to 3.31). Conclusion Completion of globally available digital training by engaged teams can alter anastomotic leak rates. Registration number: NCT04270721 (http://www.clinicaltrials.gov)