cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.7743749
title: SYHDA – System of Hydrological Data Acquisition and Analysis

description: ABSTRACT Acquisition and analysis of hydrological series are essential activities for hydrological studies in watersheds. However, they require time and are usually complex and susceptible to human errors. In order to minimize these problems, computational tools are often used for hydrological analysis, although there are few of them in Brazil. This technical note aims to provide a structured document with information on the motivation, development, conception, main functionalities, and applications of the System of Hydrological Data Acquisition and Analysis (SYHDA). SYHDA is a software intended for acquisition and analysis of hydrological data (rainfall and streamflow) and was fully idealized to enable the user to deal with the country’s leading hydrology databases. It has several modules that include analysis by descriptive statistics and graphical tools, seasonality analysis of streamflows, non-parametric tests, and at-site and regional probabilistic modeling. SYHDA has been used in numerous scientific studies, which give grounds to affirm that it demonstrates a great potential to be used in both everyday and complex activities demanded by the scientific and technical community of hydrology and related areas.
DOI: 10.6084/m9.figshare.7743749.v1
title: SYHDA – System of Hydrological Data Acquisition and Analysis

description: ABSTRACT Acquisition and analysis of hydrological series are essential activities for hydrological studies in watersheds. However, they require time and are usually complex and susceptible to human errors. In order to minimize these problems, computational tools are often used for hydrological analysis, although there are few of them in Brazil. This technical note aims to provide a structured document with information on the motivation, development, conception, main functionalities, and applications of the System of Hydrological Data Acquisition and Analysis (SYHDA). SYHDA is a software intended for acquisition and analysis of hydrological data (rainfall and streamflow) and was fully idealized to enable the user to deal with the country’s leading hydrology databases. It has several modules that include analysis by descriptive statistics and graphical tools, seasonality analysis of streamflows, non-parametric tests, and at-site and regional probabilistic modeling. SYHDA has been used in numerous scientific studies, which give grounds to affirm that it demonstrates a great potential to be used in both everyday and complex activities demanded by the scientific and technical community of hydrology and related areas.
DOI: 10.6084/m9.figshare.10258451
title: A methodology to assess vulnerability in small communities drinking water systems

description: ABSTRACT In many countries, small community systems have an important role as suppliers of drinking water for large part of the population. These systems must be evaluated with respect to their capacity to produce and deliver safe drinking water. As there are thousands of small systems to be evaluated in any given region, it is necessary to develop a procedure for selecting a representative sample, as well as the use of indicators that can provide information about the state of the systems. The objective of this study was to propose and apply a methodology to evaluate the vulnerability of small communities drinking water systems. The methodology includes the application of a statistical method to select a representative sample of systems in a region. It also proposes vulnerability indicators, ratings and an index. As a case study, the methodology was applied to determine the vulnerability of small community drinking water systems in the state of Rio Grande do Sul, Brazil. Data collected with application of the proposed methodology indicated that 67% of the surveyed systems were classified as having intermediate and high levels of vulnerabilities, hence at risk of distributing water that is not safe for drinking.
DOI: 10.6084/m9.figshare.10258451.v1
title: A methodology to assess vulnerability in small communities drinking water systems

description: ABSTRACT In many countries, small community systems have an important role as suppliers of drinking water for large part of the population. These systems must be evaluated with respect to their capacity to produce and deliver safe drinking water. As there are thousands of small systems to be evaluated in any given region, it is necessary to develop a procedure for selecting a representative sample, as well as the use of indicators that can provide information about the state of the systems. The objective of this study was to propose and apply a methodology to evaluate the vulnerability of small communities drinking water systems. The methodology includes the application of a statistical method to select a representative sample of systems in a region. It also proposes vulnerability indicators, ratings and an index. As a case study, the methodology was applied to determine the vulnerability of small community drinking water systems in the state of Rio Grande do Sul, Brazil. Data collected with application of the proposed methodology indicated that 67% of the surveyed systems were classified as having intermediate and high levels of vulnerabilities, hence at risk of distributing water that is not safe for drinking.
DOI: 10.6084/m9.figshare.11804211
title: Alternative model of intense rainfall equation obtained from daily rainfall disaggregation

description: ABSTRACT The objective of this work was to propose an alternative model of IDF equation based on the disaggregation of daily rainfall. Data from the rainfall gauge station code 02649018 of the Brazilian National Water Agency from the period 1968 to 2011 were used. Several extreme event probability distributions were adjusted. Rainfall intensity with a return period of 2 to 100 years and durations of 5 to 1440 minutes were estimated using the relationships between rainfall for different durations. The four coefficients of the traditionally used IDF equation were adjusted, obtaining a sum of squares of deviations equal to 695.1 (mm.h-1)2 and standard error of estimation equal to 2.69 mm.h-1. For the model of the intense rainfall equation proposed, that relates the rain intensity and duration with the maximum daily rainfall, the sum of squares of the deviations was 33.6 (mm.h-1)2 and the standard estimated error was 0.59 mm.h-1. Including the return period in the model, we obtained squares of the deviations of 129.4 (mm.h-1)2, with a standard error of estimation of 1.16 mm.h-1. The models proposed have, besides better estimation accuracy, the advantages of facilitating the updating only by updating the maximum daily precipitation and sub serve the spatial representation.
DOI: 10.6084/m9.figshare.11804211.v1
title: Alternative model of intense rainfall equation obtained from daily rainfall disaggregation

description: ABSTRACT The objective of this work was to propose an alternative model of IDF equation based on the disaggregation of daily rainfall. Data from the rainfall gauge station code 02649018 of the Brazilian National Water Agency from the period 1968 to 2011 were used. Several extreme event probability distributions were adjusted. Rainfall intensity with a return period of 2 to 100 years and durations of 5 to 1440 minutes were estimated using the relationships between rainfall for different durations. The four coefficients of the traditionally used IDF equation were adjusted, obtaining a sum of squares of deviations equal to 695.1 (mm.h-1)2 and standard error of estimation equal to 2.69 mm.h-1. For the model of the intense rainfall equation proposed, that relates the rain intensity and duration with the maximum daily rainfall, the sum of squares of the deviations was 33.6 (mm.h-1)2 and the standard estimated error was 0.59 mm.h-1. Including the return period in the model, we obtained squares of the deviations of 129.4 (mm.h-1)2, with a standard error of estimation of 1.16 mm.h-1. The models proposed have, besides better estimation accuracy, the advantages of facilitating the updating only by updating the maximum daily precipitation and sub serve the spatial representation.
DOI: 10.6084/m9.figshare.11804217
title: Extreme pressure forecasting methodology for the hydraulic jump downstream of a low head spillway

description: ABSTRACT Extreme pressures in the hydraulic jump are associated with risk of damage to the flow discharge system of dams by a series of mechanisms. Therefore, understanding and predicting these efforts are crucial for the safe and economical design of discharge systems. Thus, this paper aims to validate an existing pressure forecasting methodology for estimating the extreme pressure in the hydraulic jump with low Froude number (below 4.5). Results have shown that the method may be used for this situation on a preliminary basis. Further studies are recommended to refine the technique and to achieve results that are more precise.
DOI: 10.6084/m9.figshare.11804217.v1
title: Extreme pressure forecasting methodology for the hydraulic jump downstream of a low head spillway

description: ABSTRACT Extreme pressures in the hydraulic jump are associated with risk of damage to the flow discharge system of dams by a series of mechanisms. Therefore, understanding and predicting these efforts are crucial for the safe and economical design of discharge systems. Thus, this paper aims to validate an existing pressure forecasting methodology for estimating the extreme pressure in the hydraulic jump with low Froude number (below 4.5). Results have shown that the method may be used for this situation on a preliminary basis. Further studies are recommended to refine the technique and to achieve results that are more precise.
DOI: 10.6084/m9.figshare.11804199
title: Estimating groundwater resources of the Içá-Solimões Aquifer System in the Urucu Oil Province Central Amazon Region, Brazil, focused on a balance between availability and water demand

description: ABSTRACT Hydrogeologic information is still scarce in the Amazon region being required more studies for improving the understanding of local hydrogeologic contexts. The goal of this paper, focused on the Urucu Oil Province, Brazilian Central Amazon, is to quantitatively estimate groundwater resources of the Içá-Solimões Aquifer System (ISAS) in the region. The work focuses on a balance between availability and water demand, considering current and future uses, contributing to a sustainable and integrated use of groundwater. Cartographic, lithologic and geophysical logs were analyzed coupled with ISAS hydraulic data (transmissivity, hydraulic conductivity, and storativity) and its local aquifer geometries, as well as the potentiometric surface map to estimate values of total and renewable groundwater resources, sustainable yields, and well-field facility capacities. Results showed the portion of the Içá-Solimões Aquifer System has a total groundwater resource of 0.45 km3. As there is a groundwater consumptive projection to 2050 close to 2.7 x 10-3 km3 yr–1 and the aquifer system has a sustainable yield of 3 x 10-3 km3 yr–1, the current resource allocation for future consumption rate appears to be sustainable.
DOI: 10.6084/m9.figshare.11804199.v1
title: Estimating groundwater resources of the Içá-Solimões Aquifer System in the Urucu Oil Province Central Amazon Region, Brazil, focused on a balance between availability and water demand

description: ABSTRACT Hydrogeologic information is still scarce in the Amazon region being required more studies for improving the understanding of local hydrogeologic contexts. The goal of this paper, focused on the Urucu Oil Province, Brazilian Central Amazon, is to quantitatively estimate groundwater resources of the Içá-Solimões Aquifer System (ISAS) in the region. The work focuses on a balance between availability and water demand, considering current and future uses, contributing to a sustainable and integrated use of groundwater. Cartographic, lithologic and geophysical logs were analyzed coupled with ISAS hydraulic data (transmissivity, hydraulic conductivity, and storativity) and its local aquifer geometries, as well as the potentiometric surface map to estimate values of total and renewable groundwater resources, sustainable yields, and well-field facility capacities. Results showed the portion of the Içá-Solimões Aquifer System has a total groundwater resource of 0.45 km3. As there is a groundwater consumptive projection to 2050 close to 2.7 x 10-3 km3 yr–1 and the aquifer system has a sustainable yield of 3 x 10-3 km3 yr–1, the current resource allocation for future consumption rate appears to be sustainable.
DOI: 10.6084/m9.figshare.11804214.v1
title: Combination of experimental and numerical approaches to determine the main characteristics of skimming flow in stepped spillways

description: ABSTRACT The traditional approach for the hydrodynamic characterization of the flow down stepped spillways is through physical modeling, which is susceptible to scale effects and has limitations related to experimental apparatus, laboratory space and the spatial discretization of data collection. Computational fluid dynamics (CFD) is an important tool for hydrodynamic analysis because, if used properly, it presents great potential for application in hydraulics. In this work, CFD was used to model the skimming flow down a stepped spillway to investigate the effects of possible pressure measurement errors due to uncertainties in the position of the sensors within the steps. The numerical model was validated through literature velocity profiles and pressure experimental data. The results showed that the best values of water fraction (α) to define free surface are α = 0.30 in the nonaerated region and α = 0.10 in the aerated region. Statistical parameters were calculated using experimental data to estimate extreme pressures. These parameters and the simulation results were used to determine that the extreme maximum and minimum pressures occur, respectively, in the region of 0.81 &lt; x/l &lt; 0.98, in the horizontal faces, and in the region of 0.93 &lt; y/h &lt; 0.98, in the vertical faces.
DOI: 10.6084/m9.figshare.11804214
title: Combination of experimental and numerical approaches to determine the main characteristics of skimming flow in stepped spillways

description: ABSTRACT The traditional approach for the hydrodynamic characterization of the flow down stepped spillways is through physical modeling, which is susceptible to scale effects and has limitations related to experimental apparatus, laboratory space and the spatial discretization of data collection. Computational fluid dynamics (CFD) is an important tool for hydrodynamic analysis because, if used properly, it presents great potential for application in hydraulics. In this work, CFD was used to model the skimming flow down a stepped spillway to investigate the effects of possible pressure measurement errors due to uncertainties in the position of the sensors within the steps. The numerical model was validated through literature velocity profiles and pressure experimental data. The results showed that the best values of water fraction (α) to define free surface are α = 0.30 in the nonaerated region and α = 0.10 in the aerated region. Statistical parameters were calculated using experimental data to estimate extreme pressures. These parameters and the simulation results were used to determine that the extreme maximum and minimum pressures occur, respectively, in the region of 0.81 &lt; x/l &lt; 0.98, in the horizontal faces, and in the region of 0.93 &lt; y/h &lt; 0.98, in the vertical faces.
DOI: 10.6084/m9.figshare.11804202
title: Simulation of the occurrence of drought events via copulas

description: ABSTRACT This study presents a method based on Archimedean and Gaussian copulas to simulate the occurrence of hydrological droughts. The droughts were characterized by theory of runs for four threshold levels and six univariate probability distributions were evaluated to represent the probabilistic behavior of their severities and durations. The Akaike Information Criterion was used to select the better univariate probabilistic models, while their hypotheses of goodness-of-fit to the historical data were evaluated by Kolmogorov-Smirnov test. Based on the univariate probability distributions of severities and durations, Archimedean and Gaussian copulas were used in the bivariate analysis of the drought events. The proposed method proves to be a useful tool to simulate the occurrence of drought events, preserving the laws of probability of the severities and durations and the dependency between both.
DOI: 10.6084/m9.figshare.11804202.v1
title: Simulation of the occurrence of drought events via copulas

description: ABSTRACT This study presents a method based on Archimedean and Gaussian copulas to simulate the occurrence of hydrological droughts. The droughts were characterized by theory of runs for four threshold levels and six univariate probability distributions were evaluated to represent the probabilistic behavior of their severities and durations. The Akaike Information Criterion was used to select the better univariate probabilistic models, while their hypotheses of goodness-of-fit to the historical data were evaluated by Kolmogorov-Smirnov test. Based on the univariate probability distributions of severities and durations, Archimedean and Gaussian copulas were used in the bivariate analysis of the drought events. The proposed method proves to be a useful tool to simulate the occurrence of drought events, preserving the laws of probability of the severities and durations and the dependency between both.
DOI: 10.6084/m9.figshare.11804208
title: Analysis of currents on the continental shelf off the Santa Catarina Island through measured data

description: ABSTRACT The coastal currents and forcing agents that conduct them are still little-known in the internal continental shelf of Santa Catarina. Therefore, this work aimed to analyze the data of currents measured off the Island of Santa Catarina in order to better comprehend its patterns and forcing agents. The three measuring stations were installed in shallow water near the Arvoredo Biological Marine Reserve (ST01), Jurerê Beach (ST02) and Ingleses Beach (ST03). Data were collected by a current meter from January 22, 2014 to December 17, 2014. In the consisted data set, it was performed a basic statistical analysis, spectral decomposition and harmonic analysis in the tide components. All the stations presented a resulting southward flow, especially the station next to Arvoredo Marine Biological Reserve (ST01). The meteorological forcing has a strong contribution to the magnitude and direction of component v (alongshore). While the tidal component has greater importance in the cross-shore flow (component u). The wind showed a strong correlation with currents and the local level, indicating to be the main forcing agent of the flow in the subtidal frequency.
DOI: 10.6084/m9.figshare.11804208.v1
title: Analysis of currents on the continental shelf off the Santa Catarina Island through measured data

description: ABSTRACT The coastal currents and forcing agents that conduct them are still little-known in the internal continental shelf of Santa Catarina. Therefore, this work aimed to analyze the data of currents measured off the Island of Santa Catarina in order to better comprehend its patterns and forcing agents. The three measuring stations were installed in shallow water near the Arvoredo Biological Marine Reserve (ST01), Jurerê Beach (ST02) and Ingleses Beach (ST03). Data were collected by a current meter from January 22, 2014 to December 17, 2014. In the consisted data set, it was performed a basic statistical analysis, spectral decomposition and harmonic analysis in the tide components. All the stations presented a resulting southward flow, especially the station next to Arvoredo Marine Biological Reserve (ST01). The meteorological forcing has a strong contribution to the magnitude and direction of component v (alongshore). While the tidal component has greater importance in the cross-shore flow (component u). The wind showed a strong correlation with currents and the local level, indicating to be the main forcing agent of the flow in the subtidal frequency.
DOI: 10.6084/m9.figshare.11804205
title: A regional similarity-based approach for sub-daily rainfall nonparametric generation

description: ABSTRACT Rainfall time series with high temporal resolution are required for estimating storm events for the design of urban drainage systems, for performing rainfall-runoff simulation in small catchments and for modeling flash-floods. Nonetheless, large and continuous sub-daily rainfall samples are often unavailable. For dealing with the limited availability of high-resolution rainfall records, in both time and space, this paper explored an alternative version of the k-nearest neighbors algorithm, coupled with the method of fragments (KNN-MOF model), which utilizes a state-based logic for simulating consecutive wet days and a regionalized similarity-based approach for sampling fragments from hydrologically similar nearby stations. The proposed disaggregation method was applied to 40 rainfall gauging stations located in the São Francisco and Doce river catchments. Disaggregation of daily rainfall was performed for the durations of 60, 180 and 360 minutes. Results indicated the model presented an appropriate performance to disaggregate daily rainfall, reasonably reproducing sub-daily summary statistics. In addition, the annual block-maxima behavior, even for low exceedance probabilities, was relatively well described, although not all expected variability in the quantiles was properly summarized by the model. Overall, the proposed approach proved a sound and easy to implement alternative for simulating continuous sub-daily rainfall amounts from coarse-resolution records.
DOI: 10.6084/m9.figshare.11804205.v1
title: A regional similarity-based approach for sub-daily rainfall nonparametric generation

description: ABSTRACT Rainfall time series with high temporal resolution are required for estimating storm events for the design of urban drainage systems, for performing rainfall-runoff simulation in small catchments and for modeling flash-floods. Nonetheless, large and continuous sub-daily rainfall samples are often unavailable. For dealing with the limited availability of high-resolution rainfall records, in both time and space, this paper explored an alternative version of the k-nearest neighbors algorithm, coupled with the method of fragments (KNN-MOF model), which utilizes a state-based logic for simulating consecutive wet days and a regionalized similarity-based approach for sampling fragments from hydrologically similar nearby stations. The proposed disaggregation method was applied to 40 rainfall gauging stations located in the São Francisco and Doce river catchments. Disaggregation of daily rainfall was performed for the durations of 60, 180 and 360 minutes. Results indicated the model presented an appropriate performance to disaggregate daily rainfall, reasonably reproducing sub-daily summary statistics. In addition, the annual block-maxima behavior, even for low exceedance probabilities, was relatively well described, although not all expected variability in the quantiles was properly summarized by the model. Overall, the proposed approach proved a sound and easy to implement alternative for simulating continuous sub-daily rainfall amounts from coarse-resolution records.