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Pedro Henrique Lima Alencar; Eva Nora Paton; José Carlos de Araújo. Supplementary material to "Maximum Entropy Distribution of Rainfall Intensity and Duration – MEDRID: a method for precipitation temporal downscaling for sediment delivery assessment". 2021, 1 .
AMA StylePedro Henrique Lima Alencar, Eva Nora Paton, José Carlos de Araújo. Supplementary material to "Maximum Entropy Distribution of Rainfall Intensity and Duration – MEDRID: a method for precipitation temporal downscaling for sediment delivery assessment". . 2021; ():1.
Chicago/Turabian StylePedro Henrique Lima Alencar; Eva Nora Paton; José Carlos de Araújo. 2021. "Supplementary material to "Maximum Entropy Distribution of Rainfall Intensity and Duration – MEDRID: a method for precipitation temporal downscaling for sediment delivery assessment"." , no. : 1.
Scarcity of precipitation data is yet a problem in erosion modelling, especially when working in remote and data scarce areas. While much effort was made to use remote sensing and reanalysis data, they are still considered to be not completely reliable, notably for sub-daily measures such as duration and intensity. A way forward are statistical analyses, which can help modellers to obtain sub-daily precipitation characteristics by using daily totals. In this paper, we propose a novel method (Maximum Entropy Distribution of Rainfall Intensity and Duration – MEDRID) to assess the duration and intensity of sub-daily rainfalls relevant for modelling of sediment delivery ratios. We use the generated data to improve the sediment yield assessment in seven catchments with area varying from 10−3 to 10+2 km2 and broad timespan of monitoring (1 to 81 years). The best probability density function derived from MEDRID to reproduce sub-daily duration is the generalised gamma distribution (NSE = 0.98), whereas for the rain intensity it is the uniform (NSE = 0.87). The MEDRID method coupled with the SYPoME model (Sediment Yield using the Principle of Maximum Entropy) represents a significant improvement over empirically-based SDR models, given its average absolute error of 21 % and a Nash-Sutcliffe Efficiency of 0.96 (rather than 105 % and −4.49, respectively
Pedro Henrique Lima Alencar; Eva Nora Paton; José Carlos de Araújo. Maximum Entropy Distribution of Rainfall Intensity and Duration – MEDRID: a method for precipitation temporal downscaling for sediment delivery assessment. 2021, 2021, 1 -27.
AMA StylePedro Henrique Lima Alencar, Eva Nora Paton, José Carlos de Araújo. Maximum Entropy Distribution of Rainfall Intensity and Duration – MEDRID: a method for precipitation temporal downscaling for sediment delivery assessment. . 2021; 2021 ():1-27.
Chicago/Turabian StylePedro Henrique Lima Alencar; Eva Nora Paton; José Carlos de Araújo. 2021. "Maximum Entropy Distribution of Rainfall Intensity and Duration – MEDRID: a method for precipitation temporal downscaling for sediment delivery assessment." 2021, no. : 1-27.
Studies that allow the estimation of evaporation in reservoirs represent an important action for the adequate management of water resources. Thus, this study aimed at estimating evaporation in the tropical reservoir Gavião, located in the municipality of Pacatuba, Ceará, Brazil, and to verify the effect of these estimates on the water availability of the reservoir using the VYELAS model. The results of Penman's methods and the Water Balance were compared with the values obtained from the hydrostatic pressure sensor, the most accurate. It was possible to verify that, in relation to the pressure difference method, all the conventional methods overestimate the evaporation in the reservoir. The method that presented estimates closer to those obtained by the pressure difference sensor was that of Penman, based on data from an onboard station in the lake, with a deviation of only 12%. The method of water balance also presented reliable results for monthly average. The two methods usually accepted in the evaporation calculation (water balance ignoring the infiltration; and Penman's method for meteorological station data on land distant from the lake) presented the most disturbing evaporation values significantly altering the water availability. The results of the VYELAS model showed that evaporated flows, estimated by several methods, exceeded the reference flow by up to 83%. The results demonstrate the great sensitivity of the estimate of water availability in relation to the evaporation rate in the lake.
Gabriela Pinheiro Feitosa; José Carlos DE Araújo; Mário Ubirajara Gonçalves Barros. DIFFERENT METHODS FOR MEASURING EVAPORATION IN A TROPICAL RESERVOIR: THE CASE OF THE GAVIÃO RESERVOIR IN THE STATE OF CEARÁ. Revista Caatinga 2021, 34, 410 -421.
AMA StyleGabriela Pinheiro Feitosa, José Carlos DE Araújo, Mário Ubirajara Gonçalves Barros. DIFFERENT METHODS FOR MEASURING EVAPORATION IN A TROPICAL RESERVOIR: THE CASE OF THE GAVIÃO RESERVOIR IN THE STATE OF CEARÁ. Revista Caatinga. 2021; 34 (2):410-421.
Chicago/Turabian StyleGabriela Pinheiro Feitosa; José Carlos DE Araújo; Mário Ubirajara Gonçalves Barros. 2021. "DIFFERENT METHODS FOR MEASURING EVAPORATION IN A TROPICAL RESERVOIR: THE CASE OF THE GAVIÃO RESERVOIR IN THE STATE OF CEARÁ." Revista Caatinga 34, no. 2: 410-421.
The multiple-year drought that started in 2011 and reached climax in 2015 was the most severe and prolonged one in the semiarid northeastern (NE) Brazil in recent decades. This study aimed to investigate the reservoir surface water volume (SWV) variation in NE Brazil from 2009 to 2017 in four representative regions covering a total area of approximately 10,000 km2 there and encompassing 2,140 reservoirs (areas range from 0.003 to 21 km2). High-resolution (10 m) digital elevation models (DEMs) were generated from the TanDEM-X data acquired during October–December 2015 to represent the reservoirs' bathymetric maps. The water extents in the reservoirs were delineated from high-resolution (6.5 m) RapidEye images acquired during 2009–2017. The combination of the aforementioned two variables yielded reservoir SWV with an accuracy of 0.64 × 106–1.06 × 106 m3, corresponding to 3.1%–5.6% of the maximum SWV in the reservoirs. The results showed that: 1) 81%–99% of the reservoirs in the four regions were from the groups with maximum water extent 50 ha and contributed 40%–98% to the regional SWV; 2) From 2009 to 2017, reservoir SWV in the four regions decreased at the rates of 2.3 × 106–17.8 × 106 m3/year; and 3) The SWV in the reservoirs responded differently to the regional terrestrial water budget, i.e. the differences between precipitation and evapotranspiration (P-ET). This study filled the data gap of bathymetric maps for the 2140 reservoirs, regardless of their sizes and macrophyte coverage. The SWV variations derived in those reservoirs over a period covering the recent drought can support better preparedness for drought in NE Brazil and better understanding of the regional hydrology in semi-arid regions.
Shuping Zhang; Saskia Foerster; Pedro Medeiros; José Carlos de Araújo; Zheng Duan; Axel Bronstert; Bjoern Waske. Mapping regional surface water volume variation in reservoirs in northeastern Brazil during 2009–2017 using high-resolution satellite images. Science of The Total Environment 2021, 789, 147711 .
AMA StyleShuping Zhang, Saskia Foerster, Pedro Medeiros, José Carlos de Araújo, Zheng Duan, Axel Bronstert, Bjoern Waske. Mapping regional surface water volume variation in reservoirs in northeastern Brazil during 2009–2017 using high-resolution satellite images. Science of The Total Environment. 2021; 789 ():147711.
Chicago/Turabian StyleShuping Zhang; Saskia Foerster; Pedro Medeiros; José Carlos de Araújo; Zheng Duan; Axel Bronstert; Bjoern Waske. 2021. "Mapping regional surface water volume variation in reservoirs in northeastern Brazil during 2009–2017 using high-resolution satellite images." Science of The Total Environment 789, no. : 147711.
Flash droughts recently started to draw a larger curiosity to its occurrence and, therefore, its features. Differently from the slow development of droughts (months to years), flash droughts evolve over a short time (weeks) of a rapid intensification. Over the last few years, multiple methods for flash drought identification were proposed. Those methods, although sharing some characteristics, as tracking of soil water content and/or evapotranspiration (actual and potential), end up not flagging the same periods under flash drought events. We compared six well-known flash drought identification methods from the literature and used two different datasets. The datasets are: (1) the FluxNET15 dataset (Pastorello et al, 2020), a collection of worldwide, quality-controlled measurements of several hydroclimatic variables, such as soil water content, precipitation, temperature, and wind speed; and (2) the ECMWF Reanalysis 5 (ERA5 – Hersbach et al., 2019) provides over three hundred different data including soil water content in multiple levels, evapotranspiration, precipitation, and temperature. Ten stations from FluxNET15 were selected and the data from the ERA5 on the respective pixels was acquired. The aim of this work is to compare the event identification of different methods using different datasets as input (direct measures and reanalysis based).
Pedro Henrique Lima Alencar; José Carlos de Araújo; Eva Nora Paton. Flash Drought identification – a comparison of definitions across different datasets. 2021, 1 .
AMA StylePedro Henrique Lima Alencar, José Carlos de Araújo, Eva Nora Paton. Flash Drought identification – a comparison of definitions across different datasets. . 2021; ():1.
Chicago/Turabian StylePedro Henrique Lima Alencar; José Carlos de Araújo; Eva Nora Paton. 2021. "Flash Drought identification – a comparison of definitions across different datasets." , no. : 1.
Evapotranspiration (ET) plays an important role in integrated water resource planning, development and management. This process is particularly relevant in semiarid regions. The aim of this study is, hence, to compare spatial and temporal patterns of actual evapotranspiration, as well as the temporal trends in two different semiarid forests, Caatinga (Brazil) and Tierra de Pinares (Spain). We used the Surface Energy Balance Algorithm for Land (SEBAL) to assess actual evapotranspiration (ETa) in both areas. In the Brazilian semiarid forest, Caatinga is the main vegetation, while it is Pinares in Spain. For this purpose, 69 Landsat‐5 and 42 Landsat‐8 images (1995 – 2019) were used. The Mann‐Kendall test was applied to assess the occurrence of trends in precipitation, temperature and potential evapotranspiration data; and the Temporal Stability Index (TSI) to know which areas have greater seasonal ETa. The annual amplitude of the potential evapotranspiration (ET0) is the same in both areas, however, the Caatinga values are higher. In the Caatinga forest, when ET0 presents its highest values throughout the year, ETa presents the lowest, and vice versa. In the Pinares forest, ETa follows the ET0 dynamics during the year, and the difference between ET0 and ETa is maximum during the summer. The Caatinga forest showed a greater spatial variation of ETa than the Pinares forest as well as a greater extension with lower temporal stability of ETa than the Pinares forest. Both the Caatinga forest and the Pinares forest showed significant positive trends in annual ET0 and ETa. We estimate that the value of ETa increases more rapidly in Pinares than in the Brazilian Caatinga. Taking Caatinga as a hydrological mirror, some consequences are expected to Pinares, such as significant changes in the water balance, increase of biodiversity vulnerability, and reduction of water availability in soil and reservoirs. This article is protected by copyright. All rights reserved.
Juliana Alcântara Costa; Joaquín Navarro‐Hevia; Carlos Alexandre Gomes Costa; José Carlos de Araújo. Temporal dynamics of evapotranspiration in semiarid native forests in Brazil and Spain using remote sensing. Hydrological Processes 2021, 35, e14070 .
AMA StyleJuliana Alcântara Costa, Joaquín Navarro‐Hevia, Carlos Alexandre Gomes Costa, José Carlos de Araújo. Temporal dynamics of evapotranspiration in semiarid native forests in Brazil and Spain using remote sensing. Hydrological Processes. 2021; 35 (3):e14070.
Chicago/Turabian StyleJuliana Alcântara Costa; Joaquín Navarro‐Hevia; Carlos Alexandre Gomes Costa; José Carlos de Araújo. 2021. "Temporal dynamics of evapotranspiration in semiarid native forests in Brazil and Spain using remote sensing." Hydrological Processes 35, no. 3: e14070.
With an area of 6,200 km2, the Gilbués badlands region in Brazilian drylands is the largest desertification site in the country. It is located upstream the Boa Esperança Hydroelectric Power Plant and contiguous to an important Brazilian agricultural area. However, primary quantitative data on erosive processes are scarce or inexistent. We analyzed on‐site data (2018 – 2019) concerning small‐scale (hillslope and micro basin) processes: inter‐rill gross erosion, vegetation coverage factor, sediment yield, and sediment delivery ratio. We measured gross erosion in four hillslopes using metal pins; rainfall erosivity using an automatic meteorological station; soil erodibility; and siltation of five check dams that control micro basins (101–103 m2) by means of an unmanned aerial vehicle. Gross erosion (102 Mg.ha‐1.yr‐1; 7.5 mm.yr‐1) is up to 100‐fold the regional mean value and up to 45 times the tolerable soil‐loss reference value (0.17 mm.yr‐1), showing that degradation still evolves. Sparse small vegetation directly exposes two thirds of the soil, with a high vegetation factor (0.90). The sediment delivery ratio of the micro basins is 0.88, compatible with low (12%) sediment‐deposition pattern at this scale. Maner delivery‐ratio model mimicked field observation, which indicates that relief is the key element influencing sediment deposition there. The check‐dam effectiveness considerably decreased after the first decade of operation due to high siltation rates. Although the Gilbués badland occupies only 5% of a basin upstream the power plant, it contributes with 32% to its sediment load. This shows the relevance of the badland restoration for the regional sustainability of water and energy supply. This article is protected by copyright. All rights reserved.
Antonio Alisson Fernandes Simplício; Carlos Alexandre Gomes Costa; Joaquín Navarro‐Hevia; José Carlos De Araújo. Erosion at hillslope and micro‐basin scales in the Gilbués desertification region, Northeastern Brazil. Land Degradation & Development 2020, 32, 1487 -1499.
AMA StyleAntonio Alisson Fernandes Simplício, Carlos Alexandre Gomes Costa, Joaquín Navarro‐Hevia, José Carlos De Araújo. Erosion at hillslope and micro‐basin scales in the Gilbués desertification region, Northeastern Brazil. Land Degradation & Development. 2020; 32 (3):1487-1499.
Chicago/Turabian StyleAntonio Alisson Fernandes Simplício; Carlos Alexandre Gomes Costa; Joaquín Navarro‐Hevia; José Carlos De Araújo. 2020. "Erosion at hillslope and micro‐basin scales in the Gilbués desertification region, Northeastern Brazil." Land Degradation & Development 32, no. 3: 1487-1499.
This study assesses the extent to which silting increases water-scarcity risk, considering the temporal reduction of water availability and increased demand using land use and water-demand scenarios at the transition of Caatinga and Cerrado biomes of the Bocaina reservoir watershed (103hm4), in the Brazilian dry region. Methodological steps were: reservoir silting measured in-situ 20 years after dam construction; climate variables computed with the aid of a conventional station (2005-2014); soil erodibility assessed using 16 soil samples; and topography and land cover estimated based on 21 years of Landsat imagery. Three land use scenarios were generated (invariability, degradation and preservation) with the climate scenario derived from the semi-arid rainfall temporal variability; whereas two water-demand scenarios (invariability and higher efficiency) were a function of the efficiency of the irrigation systems. Water availability was calculated using the volume-yield elasticity (VYELAS) Model. The field results (1985-2015) showed a gross erosion rate of 13.5 Mg-ha-1 -yr-1 in the basin. The annual sediment yield (1.7 Mg-ha-1) and the decadal reservoir silting (1.0%) were below regional average due to the low sediment delivery ratio (12.6%) in the area. Scenario projections (2040) suggest water demand may double if irrigation methods do not improve, whereas siltation may cause water availability to decrease up to 10% in the period. In this case, the water-supply reliability will be below the recommended standard value (90%), regardless of the land use scenario. Nevertheless, simultaneous soil preservation and improved irrigation efficiency can reduce the decadal water-scarcity risk from 82% (worst scenario) to 17%.
Margarita Maria López Gil; José Carlos De Araújo; Suzana Maria Gico Lima Montenegro; Juliana Maria De Morais Sobreira Valença. INCREASE IN WATER-SCARCITY RISK IN A BRAZILIAN DRY-REGION RESERVOIR. Revista Caatinga 2020, 33, 1025 -1036.
AMA StyleMargarita Maria López Gil, José Carlos De Araújo, Suzana Maria Gico Lima Montenegro, Juliana Maria De Morais Sobreira Valença. INCREASE IN WATER-SCARCITY RISK IN A BRAZILIAN DRY-REGION RESERVOIR. Revista Caatinga. 2020; 33 (4):1025-1036.
Chicago/Turabian StyleMargarita Maria López Gil; José Carlos De Araújo; Suzana Maria Gico Lima Montenegro; Juliana Maria De Morais Sobreira Valença. 2020. "INCREASE IN WATER-SCARCITY RISK IN A BRAZILIAN DRY-REGION RESERVOIR." Revista Caatinga 33, no. 4: 1025-1036.
Gullies lead to land degradation and desertification as well as increasing environmental and societal threats, especially in arid and semiarid regions. Despite this fact, there is a lack of related research initiatives. In an effort to better understand soil loss in these systems, we studied small permanent gullies, which are a recurrent problem in the Brazilian northeastern semiarid region. The increase in sediment connectivity and the reduction of soil moisture, among other deleterious consequences, endanger this desertification-prone region and reduce its capacity to support life and economic activities. Thus, we propose a model to simulate gully-erosion dynamics, which is derived from the existing physically based models of Foster and Lane (1983) and Sidorchuk (1999). The models were adapted so as to simulate long-term erosion. A threshold area shows the scale dependency of gully-erosion internal processes (bed scouring and wall erosion). To validate the model, we used three gullies that were over 6 decades old in an agricultural basin in the Brazilian state of Ceará. The geometry of the channels was assessed using an unmanned aerial vehicle and the structure from motion technique. Laboratory analyses were performed to obtain soil properties. Local and regional rainfall data were gauged to obtain sub-daily rainfall intensities. The threshold value (cross-section area of 2 m2) characterizes when erosion in the walls, due to loss of stability, becomes more significant than sediment detachment in the wet perimeter. The 30 min intensity can be used when no complete hydrographs from rainfall are available. Our model could satisfactorily simulate the gully-channel cross-section area growth over time, yielding a Nash–Sutcliffe efficiency of 0.85 and an R2 value of 0.94.
Pedro Henrique Lima Alencar; José Carlos De Araújo; Adunias Dos Santos Teixeira. Physically based model for gully simulation: application to the Brazilian semiarid region. Hydrology and Earth System Sciences 2020, 24, 4239 -4255.
AMA StylePedro Henrique Lima Alencar, José Carlos De Araújo, Adunias Dos Santos Teixeira. Physically based model for gully simulation: application to the Brazilian semiarid region. Hydrology and Earth System Sciences. 2020; 24 (8):4239-4255.
Chicago/Turabian StylePedro Henrique Lima Alencar; José Carlos De Araújo; Adunias Dos Santos Teixeira. 2020. "Physically based model for gully simulation: application to the Brazilian semiarid region." Hydrology and Earth System Sciences 24, no. 8: 4239-4255.
Gullies are key drivers of land degradation, are important sources of sediment and increase sediment and pollutant connectivity in the catchment. They also play an important role in desertification areas, changing the water-table height and in farmlands, reducing productive areas. In this study, we attempted to model small permanent gullies, common in the Brazilian Semiarid Region, where the shallow soils limit the size of gullies cross-sections to a depth of no more than one meter. To model this process, we coupled the models of Foster and Lane (1983) and Sidorchuk (1999), in order to consider the effect of permanent gullies not considered in the first. Both models need as input the discharge peak and its duration, however, these data are frequently not available. We tested four different rain intensities (average, 60-minute, 30-minute and 15-minute), finding that the most intense 30 minutes represent the best the effects of the storms over gully erosion. The coupling of the two models is defined by a threshold that indicates when the equations for sidewall erosion proposed by Sidorchuk should be applied. To validate the model, we measured three gullies in the Brazilian Semiarid Region. The gullies were initiated in 1958 after the construction of a country road and have drainage area below 1 ha. The model yielded a Nash-Sutcliffe coefficient of 0.85.
Pedro Henrique Lima Alencar; José Carlos De Araújo; Adunias Dos Santos Teixeira. Small permanent gullies: modelling and application to a semiarid region. 2020, 1 .
AMA StylePedro Henrique Lima Alencar, José Carlos De Araújo, Adunias Dos Santos Teixeira. Small permanent gullies: modelling and application to a semiarid region. . 2020; ():1.
Chicago/Turabian StylePedro Henrique Lima Alencar; José Carlos De Araújo; Adunias Dos Santos Teixeira. 2020. "Small permanent gullies: modelling and application to a semiarid region." , no. : 1.
The North East of Brazil is characterized by a high spatial, seasonal and inter-annual variability of rainfall. The climate is semiarid with pronounced wet and dry seasons. In the federal state of Ceará, water supply for the dry season is ensured by the construction of reservoirs of various sizes. However, most of these reservoirs were built without documentation by the water management authorities. Thus, there is no complete state-wide inventory of reservoirs in Ceará. Using the satellite based global surface water dataset (GSW), this study aimed at investigating (i) the location, (ii) size, (iii) commissioning and decommissioning year as well as (iv) spatio-temporal dynamics of reservoirs in Ceará for the period 1984 - 2018.
Based on the maximum water extent of the GSW dataset, 17 919 reservoirs larger than 90 x 90 m were detected in Ceará (ii), which could be confirmed with an accuracy of 87 % for a validation dataset including 157 reservoirs regularly monitored by the State Agency for Meteorology and Water Resources in Ceará (FUNCEME). Thereby, reservoirs with a maximum water extent < 2.05 ha (category 1) form the largest and reservoirs with a maximum water extent > 50 ha (category 6) the smallest share in number of all detected reservoirs (i). In turn, reservoirs of category 6 contribute most to the water storage capacity while category 1 reservoirs contribute least. For the estimation of (de-)commissioning years (iii), the GSW monthly water history dataset was used. The years of commissioning and decommissioning were determined as the first and last year, respectively, of water being detected. The calculated commissioning years were validated against the FUNCEME dataset, whereas to date there is no validation data to confirm the decommissioning of reservoirs. The analysis of spatio-temporal dynamics of reservoir commissioning and decommissioning (iv) indicate a spatially variable increase of reservoirs until approximately 2010, followed by an intensive decrease until 2015 (analysis of extended study period currently ongoing).
Deviations in terms of commissioning years are mainly small and can be attributed to uncertainties inherent to satellite observations. Up to 2010, the detected spatio-temporal variability can be largely attributed to droughts which occurred in most parts of the state in several years and particularly severe since 2012. However, the maximum rate of large strategic reservoir construction by the public sector (for which records exist) decreased since the 1990’s, which is attributed to a shift in the adaptation strategy to water scarcity, from structural measures (construction of dams) to governance measures (water management and control). From the data presented here, it seems that this trend likewise occurred on the level of small reservoirs for which no records existed so far.
Arlena Brosinsky; Sandra Timmke; Saskia Foerster; Till Francke; Pedro Medeiros; José Carlos De Araújo. Spatio-temporal dynamics of reservoir (de-)commissioning in Ceará, NE Brazil. 2020, 1 .
AMA StyleArlena Brosinsky, Sandra Timmke, Saskia Foerster, Till Francke, Pedro Medeiros, José Carlos De Araújo. Spatio-temporal dynamics of reservoir (de-)commissioning in Ceará, NE Brazil. . 2020; ():1.
Chicago/Turabian StyleArlena Brosinsky; Sandra Timmke; Saskia Foerster; Till Francke; Pedro Medeiros; José Carlos De Araújo. 2020. "Spatio-temporal dynamics of reservoir (de-)commissioning in Ceará, NE Brazil." , no. : 1.
The Gilbués Desertification Site (GDS) is an 8,000-km² area located in the Northeast of Brazil. It comprises large continuous areas with deep (up to 30 m), wide (up to 50 m), and long (up to 6 km) gullies, as well as severe inter-rill erosion. Inside the GDS there is an experimental site, in which almost 100 check dams were constructed a decade ago to assess their feasibility as a soil-restoration initiative. For two years (2018 and 2019) we have monitored a 15-ha watershed that contains 52 check dams so as to estimate the main erosion-related parameters as well as to assess the effectiveness of the check dams. The monitoring program consisted of (i) a climate station; (ii) four hillslopes with pins every m², measured monthly to quantify gross erosion; (iii) five flights with an accurate unmanned aerial vehicle (UAV) to identify the siltation of the check dams and to parameterize the rainfall-runoff behavior; (iv) 92 soil samples in the hillslopes and inside the check dams; and (v) four infiltration experiments. The results show that (i) the gross erosion is 8 mm.yr-1, or 10² Mg.ha-1.yr-1, a value ten times higher than the region average; (ii) based on the silting of the check dams, the sediment yield averaged 85 Mg.ha-1.yr-1, 20 times higher than the regional mean value, which is partially explained by the small size of the watersheds (10²-10³ m²); (iii) the Wischmeier vegetation C factor is 0.9, showing high degree of vegetative-cover degradation; and (iv) the sediment delivery ratio was 0.8, which could be satisfactorily represented by the Maner equation. These results show that, although the GDS corresponds to only 10% of the Boa Esperança (5,000 hm³) hydroelectric power plant basin, it may cause 60% of the reservoir silting. The GDS soil has also shown specific properties: 71% of the soil mass has a diameter of ~ 0.1 mm; there is a high rate of open macro-pores when the soil is dry (they close shortly after a moderate rainfall event ~ 40 mm); and it is prone to form gravel-like particles that silt in the reservoir delta (despite its fine diameter). Last, we observed that the check dams – as they were built – are not a sustainable solution: after a decade, nearly 10% are spilling due to the high siltation rates, causing dam-wall erosion and instability; and three dams have presented piping, with discharges (0.2 – 0.7 L.s-1) one thousand times higher than the expected percolation flow through the dams.
José Carlos De Araújo; Antonio Álisson Simplício; Francisco Jairo Pereira; Carlos Alexandre Gomes Costa. Erosion assessment in the desertification site of Gilbues, Brazil. 2020, 1 .
AMA StyleJosé Carlos De Araújo, Antonio Álisson Simplício, Francisco Jairo Pereira, Carlos Alexandre Gomes Costa. Erosion assessment in the desertification site of Gilbues, Brazil. . 2020; ():1.
Chicago/Turabian StyleJosé Carlos De Araújo; Antonio Álisson Simplício; Francisco Jairo Pereira; Carlos Alexandre Gomes Costa. 2020. "Erosion assessment in the desertification site of Gilbues, Brazil." , no. : 1.
In dry environments, society has long implemented infrastructure to adapt to water scarcity, but unanticipated feedbacks have threatened the supply-demand balance. For instance, construction of dams increases the water residence time in highly impounded basins, causing sediment and nutrient accumulation in water supply reservoirs. Reuse of reservoirs’ sediment as fertilizer sustainably benefits agricultural and water systems by: replacing fine particles and nutrients to soils, previously lost by erosion; recovering water quantity and quality by the removal of nutrient-enriched sediments from reservoirs. In the last 5 years we have assessed the potential of the sediment reuse technique for soil fertilization and water conservation in the semiarid Ceará State (149 000 km²), Brazil, where there is a dense network of more than 20 000 dams with considerable silting and eutrophication. Our previous studies demonstrated that:
In spite of the recent advances, sediment recycling must go through some phases in order to be included in the public policy agenda. Our ongoing and planned studies focus on the generation of basic data, real-scale testing, simulations under diverse environmental contexts, elaboration of guidelines and disclosure. Spectroscopy has been successfully applied to characterize sediment and soil properties and reduce the costly laboratory analysis. Additionally, data acquisition will be supported by remote sensing approaches based on hyperspectral satellite images that will become available in the near future (Prisma, EnMAP). Such data will be used to estimate nutrient availability in sediments and deficit in the soils to generate a map of the sediment reuse potential in Ceará. Field scale growth experiments are to be conducted for the main crops cultivated in the study region, in contrast to the indoor controlled conditions of our previous assessment. Furthermore, we are developing a modelling tool to quantify the impacts of the sediment reuse practice on water quality, enabling us to expand our previous study to other reservoirs and to test its effectiveness to water conservation.
Pedro Medeiros; Brennda Braga; Camila Lira; Arlena Brosinsky; Saskia Foerster; Franklin Gondim; José Carlos De Araújo. Potential of sediment reuse for soil fertilization and water conservation in drylands. 2020, 1 .
AMA StylePedro Medeiros, Brennda Braga, Camila Lira, Arlena Brosinsky, Saskia Foerster, Franklin Gondim, José Carlos De Araújo. Potential of sediment reuse for soil fertilization and water conservation in drylands. . 2020; ():1.
Chicago/Turabian StylePedro Medeiros; Brennda Braga; Camila Lira; Arlena Brosinsky; Saskia Foerster; Franklin Gondim; José Carlos De Araújo. 2020. "Potential of sediment reuse for soil fertilization and water conservation in drylands." , no. : 1.
In this research, the trade-off between the number of restrictions and the robustness of the primary formulation of entropy models was evaluated. The performance of six hydrodynamic models in open channels was assessed based on 1730 Laser-Doppler anemometry data. It was investigated whether it is better to use an entropy-based model with more restrictions and a weak primary formulation or a model with fewer restrictions, but with a strong formulation. In addition, it was also investigated whether the model performance improves with the insertion of restrictions. Three of the investigated models have a weak formulation (open-channel velocity field represented by Cartesian coordinates); while the other three models have a strong formulation, according to which isovels are represented by curvilinear coordinates. The results indicated that models with two restrictions performed better than those with one restriction, since the additional restriction includes information relevant to the system. Models with three restrictions perform worse than those with two restrictions, because the information lost due to the use of a numerical solution was more substantial than the information gained by the third restriction. In conclusion, a strong primary formulation brought more information to the system than the inclusion of a third constraint.
Antonio Viana Da Silva Filho; José Carlos De Araújo; Armin Raabe. Trade-off between number of constraints and primary-statement robustness in entropy models: the case of the open-channel velocity field. Anais da Academia Brasileira de Ciências 2020, 92, e20200594 .
AMA StyleAntonio Viana Da Silva Filho, José Carlos De Araújo, Armin Raabe. Trade-off between number of constraints and primary-statement robustness in entropy models: the case of the open-channel velocity field. Anais da Academia Brasileira de Ciências. 2020; 92 (3):e20200594.
Chicago/Turabian StyleAntonio Viana Da Silva Filho; José Carlos De Araújo; Armin Raabe. 2020. "Trade-off between number of constraints and primary-statement robustness in entropy models: the case of the open-channel velocity field." Anais da Academia Brasileira de Ciências 92, no. 3: e20200594.
CARACTERÍSTICAS FÍSICAS DE CÁPSULAS POROSAS PARA USO NA IRRIGAÇÃO LOCALIZADA PEDRO IDELANO DE ALENCAR FELÍCIO1; RENATO SÍLVIO DA FROTA RIBEIRO1; ALEXSANDRO OLIVEIRA DA SILVA1; JOSÉ CARLOS DE ARAÚJO1 E RAIMUNDO NONATO TÁVORA COSTA1 1 Departamento de Engenharia Agrícola, Universidade Federal do Ceará, Av. Mr. Hull, s/n, Pici, CEP:60356-001, Fortaleza, Ceará, Brasil. E-mail: [email protected]; [email protected]; [email protected]; [email protected]; [email protected] 1 RESUMO Há diversos usos para as cápsulas porosas na agricultura, contudo, estas devem ser caracterizadas por parâmetros de avaliação como pressão de borbulhamento e condutância hidráulica. O objetivo da pesquisa foi aferir as características físicas de cápsulas porosas para uso na irrigação localizada. Para o sistema de irrigação proposto, utilizaram-se dez cápsulas porosas na execução do ensaio experimental que consistiu em um delineamento inteiramente casualizado com três tratamentos, constando de diferentes manejos de irrigação (manejo via clima, via solo e via cápsula porosa) com dez repetições, totalizando 30 unidades experimentais, tendo sido avaliados parâmetros de produção e crescimento da cultura do rabanete. A pressão de borbulhamento média observada foi de 2,34 atm, enquanto a condutância hidráulica apresentou valor médio de 9,27 x 10-6 cm² s-1. Para a cultura em estudo não houve diferenças entre os tratamentos estudados, sendo que a massa fresca da raiz apresentou valores de 7,4 g planta-1 para o manejo via clima e 4,7 g planta-1 para o manejo via cápsula porosa, não sendo estatisticamente diferentes pelo teste de Tukey (p
Pedro Idelano De Alencar Felício; Renato Silvio Da Frota Ribeiro; Alexsandro Oliveira Silva; José Carlos De Araújo; Raimundo Nonato Távora Costa. CARACTERÍSTICAS FÍSICAS DE CÁPSULAS POROSAS PARA USO NA IRRIGAÇÃO LOCALIZADA. IRRIGA 2019, 24, 861 -873.
AMA StylePedro Idelano De Alencar Felício, Renato Silvio Da Frota Ribeiro, Alexsandro Oliveira Silva, José Carlos De Araújo, Raimundo Nonato Távora Costa. CARACTERÍSTICAS FÍSICAS DE CÁPSULAS POROSAS PARA USO NA IRRIGAÇÃO LOCALIZADA. IRRIGA. 2019; 24 (4):861-873.
Chicago/Turabian StylePedro Idelano De Alencar Felício; Renato Silvio Da Frota Ribeiro; Alexsandro Oliveira Silva; José Carlos De Araújo; Raimundo Nonato Távora Costa. 2019. "CARACTERÍSTICAS FÍSICAS DE CÁPSULAS POROSAS PARA USO NA IRRIGAÇÃO LOCALIZADA." IRRIGA 24, no. 4: 861-873.
Castanhão Dam, a mega-water-management work in Brazil, was built – according to the official reasoning – to reduce water scarcity and boost the economy. It compulsorily displaced over 10,000 people, whose satisfaction with the new standard of living, a decade after the resettlement, was marginally negative, contrasting with the pre-construction expectations. The government invested almost exclusively in infrastructure, signaling that their focus was the corporations, not the displaced citizens. Despite the improved water availability, the quality of life did not improve for the directly affected societal groups, indicating that water scarcity is not the main development hindrance in the Brazilian semi-arid region.
Carlos Enrique Tupiño Salinas; Vládia Pinto Vidal De Oliveira; Liana Brito; André V. Ferreira; José Carlos De Araújo. Social impacts of a large-dam construction: the case of Castanhão, Brazil. Water International 2019, 44, 871 -885.
AMA StyleCarlos Enrique Tupiño Salinas, Vládia Pinto Vidal De Oliveira, Liana Brito, André V. Ferreira, José Carlos De Araújo. Social impacts of a large-dam construction: the case of Castanhão, Brazil. Water International. 2019; 44 (8):871-885.
Chicago/Turabian StyleCarlos Enrique Tupiño Salinas; Vládia Pinto Vidal De Oliveira; Liana Brito; André V. Ferreira; José Carlos De Araújo. 2019. "Social impacts of a large-dam construction: the case of Castanhão, Brazil." Water International 44, no. 8: 871-885.
Gullies are one of the most relevant erosion processes, connected to land degradation and desertification, in special in arid and semiarid regions. Despite its role, gully erosion is neglected by many models and researches. This study presents a physically-based model for small permanent gullies, typical in the Brazilian Semiarid Region. The model consists of coupling two previous models, those by Foster and Lane (1983) and Sidorchuk (1999). As both models require input data of peak discharge and duration, different rain intensities were tested. The rain intensity that suited gully erosion modelling best was the 30-minute intensity. The Foster and Lane model supplied a better response for smaller areas, where bed-channel erosion is more pronounced. The Sidorchuk model presented a better performance in larger sections, where wall erosion becomes more prominent. The experimental area is located in the semiarid State of Ceará, Brazil, in which the land use is characterised by agriculture and livestock. We measured and modelled three gullies ageing almost six decades. The threshold between the prevailing domains of each process (channel bed or wall erosion) is based on the cross-section area; and it is intrinsically connected to wall erosion: for the case study, the threshold area was approximately 2 m2. The final model, hereby called FL-SM (Foster & Lane and Sidorchuk Model) performed very well, with Nash–Sutcliffe coefficient of 0.846.
Pedro Henrique Lima Alencar; José Carlos De Araújo; Adunias Dos Santos Teixeira. Physically-based model for gully simulation: application to the Brazilian Semiarid Region. 2019, 2019, 1 -26.
AMA StylePedro Henrique Lima Alencar, José Carlos De Araújo, Adunias Dos Santos Teixeira. Physically-based model for gully simulation: application to the Brazilian Semiarid Region. . 2019; 2019 ():1-26.
Chicago/Turabian StylePedro Henrique Lima Alencar; José Carlos De Araújo; Adunias Dos Santos Teixeira. 2019. "Physically-based model for gully simulation: application to the Brazilian Semiarid Region." 2019, no. : 1-26.
Pedro Henrique Lima Alencar; José Carlos De Araújo; Adunias Dos Santos Teixeira. Supplementary material to "Physically-based model for gully simulation: application to the Brazilian Semiarid Region". 2019, 1 .
AMA StylePedro Henrique Lima Alencar, José Carlos De Araújo, Adunias Dos Santos Teixeira. Supplementary material to "Physically-based model for gully simulation: application to the Brazilian Semiarid Region". . 2019; ():1.
Chicago/Turabian StylePedro Henrique Lima Alencar; José Carlos De Araújo; Adunias Dos Santos Teixeira. 2019. "Supplementary material to "Physically-based model for gully simulation: application to the Brazilian Semiarid Region"." , no. : 1.
Conhecer o comportamento das chuvas intensas é fundamental para planejamento de bacias hidrográficas, contudo demanda robustos bancos de dados pluviográficos, ainda escassos na região semiárida brasileira. O objetivo deste trabalho foi avaliar as curvas intensidade - duração - frequência (IDF) na Bacia Experimental de Aiuaba, Ceará. Com base em medições a cada 5min durante 16 anos (2003 a 2018) foram geradas curvas IDF para os períodos de 5min, 30min, 1h, 2h, 3h, 6h, 12h, 18h e 24h e calibrados os parâmetros da equação de Otto Pfafstetter para as curvas IDF da referida bacia. Da investigação pôde-se concluir que: as curvas IDF (inéditas para a região dos Inhamuns, CE) são compatíveis com os de outros estudos em regiões semiáridas e indicaram ser uma propriedade macrorregional; a erosividade indicou um valor máximo para chuvas de duração igual a 3 horas, sendo esse um efeito combinado de alta intensidade e alta energia cinética. Esta conclusão demanda um estudo mais aprofundado, ratificando a necessidade de modelos hidrológicos capazes de identificar de maneira mais precisa variações sub-diárias dos processos hidrológicos.
Gláuber Pontes Rodrigues; J.C. Araújo. Comportamento de chuvas intensas para bacia em região semiárida de Caatinga preservada. Revista Brasileira de Ciências Agrárias - Brazilian Journal of Agricultural Sciences 2019, 14, 1 -6.
AMA StyleGláuber Pontes Rodrigues, J.C. Araújo. Comportamento de chuvas intensas para bacia em região semiárida de Caatinga preservada. Revista Brasileira de Ciências Agrárias - Brazilian Journal of Agricultural Sciences. 2019; 14 (3):1-6.
Chicago/Turabian StyleGláuber Pontes Rodrigues; J.C. Araújo. 2019. "Comportamento de chuvas intensas para bacia em região semiárida de Caatinga preservada." Revista Brasileira de Ciências Agrárias - Brazilian Journal of Agricultural Sciences 14, no. 3: 1-6.
Leaf area index (LAI) influences hydrological processes as both active and passive agents. In the Caatinga biome, little is known about LAI and its relationship with hydrological variables. Thus, the objective of this work was to measure LAI for a preserved arboreal-shrub vegetation and correlate it with hydrological variables (precipitation, evapotranspiration and soil moisture) and spectral (vegetation indices) in order to evaluate and to monitor their dynamics in time and space. The experiment was carried out in the Aiuaba Experimental Basin, considering three soil-vegetation associations and two periods (dry and rainy seasons) for three years (2014–2016). The results showed that LAI maximum is influenced by the type of soil-vegetation association and does not change over time. Among the hydrological variables, all had a significant correlation with LAI, but the best result was obtained using soil moisture. The best performance among the vegetation indexes for LAI estimation of the preserved Caatinga shrub-arboreal area was the Enhanced Vegetation Index (EVI), as shown by the analyses. The presence of clouds during the rainy season prevented a better evaluation of LAI with vegetation index. We concluded that the LAI of a preserved arboreal shrub area in Caatinga (3.5 ± 1.3 m2 m−2) can be monitored utilizing only precipitation, the precipitation-to-potential evapotranspiration ratio and soil moisture.
Cicero Lima de Almeida; Thayslan Renato Anchiêta de Carvalho; José Carlos de Araújo. Leaf area index of Caatinga biome and its relationship with hydrological and spectral variables. Agricultural and Forest Meteorology 2019, 279, 107705 .
AMA StyleCicero Lima de Almeida, Thayslan Renato Anchiêta de Carvalho, José Carlos de Araújo. Leaf area index of Caatinga biome and its relationship with hydrological and spectral variables. Agricultural and Forest Meteorology. 2019; 279 ():107705.
Chicago/Turabian StyleCicero Lima de Almeida; Thayslan Renato Anchiêta de Carvalho; José Carlos de Araújo. 2019. "Leaf area index of Caatinga biome and its relationship with hydrological and spectral variables." Agricultural and Forest Meteorology 279, no. : 107705.