Brasília, Brazil
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Pruski F.F.,Federal University of Viçosa | Bof L.H.N.,Instituto Estadual Of Meio Ambiente E Recursos Hidricos | da Silva L.M.C.,Agencia Nacional de Aguas | da Silva J.M.A.,Federal University of Viçosa | And 2 more authors.
Engenharia Agricola | Year: 2014

The consideration of the streamflow seasonality has a high potential to improve the water use. In order to give subsidies to the optimization of water use, it was evaluated the impact of the change of reference annual streamflow by the monthly streamflows in the potential water use throughout the hydrography of Paracatu sub-Basin. It was evaluated the impact on Q7,10 (lowest average streamflow during a 7-day period with an average recurrence of 10 years) and on Q95 (permanent flow present 95% of the time). The use of monthly streamflow to substitute the annual streamflow had a high potential of improvement of water resources use in the sub-Basin studied. The use of monthly Q 7,10 in substitution of annual Q 7,10 increases the potential water use that vary from about 10% in the months of lower water availability to values exceeding 200% in the months with higher availability of surface water resources. The use of monthly Q95 in substitution of the annual Q95 implies in changes oscillating from reduction of 37% in months of higher water restriction to values exceeding 100% in the months of higher availability, so the use of monthly Q95 instead of the annual Q95 enables the more rational and safe use of water resources.

Lima J.E.F.W.,Embrapa Cerrados | Lopes W.T.A.,Agencia Nacional de Aguas | Aquino F.G.,Embrapa Cerrados | Oliveira-Filho E.C.,Embrapa Cerrados | And 2 more authors.
Journal of Soils and Sediments | Year: 2014

Purpose: Payment for environmental services (PES) has assumed increasing importance in discussions about sustainable development strategies. Many of the PES programs are based on water erosion control and the corresponding environmental and economic benefits generated in the basins where they are implemented. The main objective of this study was to show how erosion susceptibility models can support PES programs. Materials and methods: The application of the Universal Soil Loss Equation (USLE) in the Sarandi Experimental River Basin (32.7 km2), located in the Federal District, Brazil, was used as a study case. Then a scheme for organizing knowledge about ecosystem services related to erosion control and water resources was performed. Considering the generated scheme, the USLE results, the land use map, and the water use in the region, we evaluated how erosion modeling could support PES programs. Results and discussion: The results show that a large part of the study basin (90%) presents "low" susceptibility to erosion, which is significant in terms of the use and conservation of ecosystem services, as well as being a limitation regarding the need for the implantation of PES programs for erosion control. Incentives for maintaining the natural vegetation in areas with higher erosion susceptibility have the greatest potential to justify PES programs in the study basin, and the sanitation company is the potential payer for erosion control in the Sarandi River Basin. Conclusions: The application of the USLE in a spatially distributed form proved to be an important support tool for land management and the implementation of PES policies. © 2013 Springer-Verlag Berlin Heidelberg.

Coelho A.C.,Agencia Nacional de Aguas | Labadie J.W.,Colorado State University | Fontane D.G.,Colorado State University
Water Resources Management | Year: 2012

Successful implementation of integrated water resources planning and management (IWRM) requires delineation of regions that are relatively homogeneous with respect to multiple criteria, including hydrographic, physical-environmental, socioeconomic, and political-administrative aspects. The water resources planning and management (WARPLAM) DSS is presented as tool for regionalization in support of IWRM through: (1) GIS processing of spatial data related to multiple criteria for defining the homogeneity of clustered base units (e.g., catchments) with respect to multiple criteria; (2) application of fuzzy set theory to development of composite measures of homogeneity over all criteria for alternative clustering of adjacent base units; and (3) development of a modified dynamic programming clustering algorithm that guarantees consistent optimal solutions based on user preferences on the relative importance of the suite of criteria considered for regionalization. The viability of WARPLAM DSS as a tool for regional delineation in support of IWRM is demonstrated through a case study application to the Tocantins-Araguaia River Basin, the second largest in Brazil. © 2012 Springer Science+Business Media B.V.

Espinoza Villar R.,University of Brasilia | Martinez J.-M.,University of Brasilia | Martinez J.-M.,University Paul Sabatier | Martinez J.-M.,Brazilian Radiological Protection and Dosimetry Institute (IRD) | And 8 more authors.
Journal of South American Earth Sciences | Year: 2013

The Madeira River may contribute nearly half of the Amazon River sediment discharge to the Atlantic Ocean, showing the highest erosion rates in the Amazon Basin. However, few studies have assessed the Madeira River sediment budget and the transport processes occurring in the main stem of the river. In this study, MODIS space-borne sensors were used to analyze the suspended sediment transport processes along the main stem of the Madeira River. Field measurements of suspended sediment concentration, spectral radiometry and granulometry were performed during 10 cruises from 2007 to 2011. The relationship between the spectral reflectance and the surface suspended sediment concentration (SSSC) was analyzed using both field radiometric measurements and satellite data. Ten-day SSSC samples acquired by the HYBAM monitoring network were used to match satellite observations with field measurements performed from 2000 to 2011. Over 900 MODIS images of 6 different locations were processed to monitor the SSSC dynamics in space and time. Satellite reflectance was found to be significantly correlated with the SSSC. However, a seasonal dependency was demonstrated, most likely caused by a variable granulometric distribution along the annual cycle. The ratio between the red and near-infrared bands was found to be free of the seasonal dependency (r = 0.79, N = 282), and a SSSC retrieval model was built from the satellite data using a bootstrap resampling technique. The satellite-retrieved SSSC time series showed excellent accuracy over the 11-year period and at two different stations located 800 km from each other. The satellite data were averaged to analyze the SSSC pattern temporally and spatially along the entire Madeira River, which provided evidence of significant sedimentation and resuspension. The backwater effect caused by the two-to-three-month lag between peak water in the Madeira and Amazon Rivers was used to predict local sedimentation near the Madeira River mouth. Our results facilitated a precise assessment of such sedimentation, which demonstrated an SSSC decrease 400 km upstream from the Madeira-Amazon confluence. © 2013 Elsevier Ltd.

Viana L.T.,Agencia Nacional de Aguas | Bustamante M.M.C.,University of Brasilia | Molina M.,U.S. Environmental Protection Agency | Pinto A.S.,University of Brasilia | And 3 more authors.
Pesquisa Agropecuaria Brasileira | Year: 2011

The objective of this work was to evaluate the effects of fire regimes and vegetation cover on the structure and dynamics of soil microbial communities, through phospholipid fatty acid (PLFA) analysis. Comparisons were made between native areas with different woody covers ("cerrado stricto sensu" and "campo sujo"), under different fire regimes, and a 20-year-old active palisadegrass pasture in the Central Plateau of Brazil. Microbial biomass was higher in the native plots than in the pasture, and the highest monthly values were observed during the rainy season in the native plots. No significant differences were observed between fire regimes or between communities from the two native vegetation types. However, the principal component (PC) analysis separated the microbial communities by vegetation cover (native x pasture) and season (wet x dry), accounting for 45.8% (PC1 and PC3) and 25.6% (PC2 and PC3), respectively, of the total PLFA variability. Changes in land cover and seasonal rainfall in Cerrado ecosystems have significant effects on the total density of soil microorganisms and on the abundance of microbial groups, especially Gram-negative and Gram-positive bacteria.

Paz A.R.,Federal University of Paraiba | Serra L.S.,Federal University of Paraiba | Silva M.R.F.,Federal University of Paraiba | Meller A.,Agencia Nacional de Aguas
Journal of Hydrologic Engineering | Year: 2016

Coupling rainfall-runoff and one-dimensional (1D)/two-dimensional (2D) hydrologic models provides the current state-of-the-art approach for predicting the extent of urban inundation, although the computational cost for running 2D models is still a major concern. This paper presents a procedure to dynamically reshape 2D numeric domain according to flooding extent evolution. The numeric domain is updated at each selected time step for reshaping (TSR) and includes grid elements directly connected to the 1D stormwater network, flooded grid elements, or grid elements within a buffer distance threshold (BDT) identified in both previous criteria. Results for an urban catchment in South Brazil are presented considering two spatial resolutions and three return-period rainfall events. An optimal relation between TSR and BDT was found and resulted in runtime savings greater than 86% in comparison to adopting a fixed boundary as catchment limits, and greater than 69% in comparison to using a fixed boundary below the 70-m elevation (which represents the maximum elevation reached by the 100-year flood). The major concepts of the proposed algorithm are straightforward and could be tested in similar 2D models. © ASCE.

de Souza F.A.O.,Agencia Nacional de Aguas | da Silva C.L.,University of Brasilia | Maggiotto S.R.,University of Brasilia | de Oliveira Junior M.P.,University of Brasilia
Revista Brasileira de Engenharia Agricola e Ambiental | Year: 2012

In Brazil, Distrito Federal region is characterized by the presence of streamlets and small rivers, which explains the importance of the discharge characterization in watersheds. This study used 13 years of hydrological data of the Capetinga watershed to analyze: the stationarity of hydrological parameters; the statistical distributions that best represent the discharge; the comparison of using short and medium series to calculate discharge; and the requirement for water rights concession according to the current legislation. The Lognormal 3 and Pearson 3 distributions best represented the maximum discharge, while Logpearson 3 distribution was best indicated for minimum discharge. Total annual precipitation, long duration mean discharge and seven-day minimum flow presented stationary series, but maximum instantaneous discharge did not. The use of short series to calculate discharge in this watershed was not reasonable, since it resulted in overestimation of the minimum discharge and underestimation of the maximum discharge. According to the legislation, the water capturing from the stream Capetinga requires a concession from the regulatory agency, in spite of the minimum discharge has a small value, which reflects its low potential of use.

The development of aquifer artificial recharge projects brings two main concerns: the groundwater contamination risk and, in the case of thermal systems, the risk of water cooling. The present study presents, from a semi-quantitative perspective, an analysis of the risk of temperature reduction of the thermal aquifer at the Caldas Novas region, state of Goiás, Brazil. The local groundwater reservoirs are classified as thermal artesian fractured aquifer systems. Three different aquifer systems are individualized: Intergranular, Paranoá and Araxá. The permanent reserves of the Paranoá and Araxá Aquifers Systems were estimated in 1,8 × 108 m3 and 4,5 × 107 m3, respectively, and the renewable reserves as 2,25 × 106 m 3/year, for Araxá, and 9,0 × 106 m 3/year, for Paranoá. These were compared to different volumes of artificial recharge water, and showed that, on a global view, there is no risk of temperature reduction for these waters, since the volumes of recharge are insignificant when compared to the reservoir. However, it is possible to find some heat loss in the surroundings of the wells that were used for the water injection, because the mixture of waters is not instantaneous and the water injected in each well affects a restricted volume of the aquifer. It had also been proposed the delimitation of the hydrogeological basin associated to the control of the hydrothermal system present in the central region of Caldas Novas. The set of available information shows that, regarding the temperature issue, the artificial recharge of the thermal aquifers is viable.

de Andrade L.A.Z.,Agencia Nacional de Aguas | Miranda H.S.,University of Brasilia
Plant Ecology | Year: 2014

The seed-bank dynamics of cerrado, a savanna-like vegetation type in central Brazil, was monitored for a year after a fire event in the mid-dry season. Fifty paired soil and litter samples were collected 1 day before and 1 day after the fire to record the immediate effects on the seed bank, and thereafter at monthly intervals to investigate the post-fire seed bank dynamics. The samples were hand-sorted and the intact seeds were classified as monocot or dicot and counted. All seeds underwent germination trials in a germination chamber for 1 month. Seeds that did not germinate were checked for the presence and viability of the embryo. The sorted soil samples were placed in a greenhouse for 6 months, and the count of emerging seedlings was added to the number of germinated and dormant seeds from the germination trials to estimate the total number of viable seeds per sample. The fire did not affect the total seed-bank density: 63 ± 8 seeds m−2 before the fire, and 83 ± 20 seeds m−2 (mean ± se) immediately after it. Although monocots represented 65 % of the pre-fire seed bank, 1 year after the fire, the monocot seed density did not reach the pre-fire value, whereas the density of dicot seeds increased threefold. After the fire, the viable seed density and species richness, decreased with the onset of the rainy season coinciding with germination in the field. Therefore, post-fire recruitment increases genetic variability and contributes to the persistence of plant populations in cerrado communities. © 2014, Springer Science+Business Media Dordrecht.

Goncalves H.C.,Agencia Nacional de Aguas | Mercante M.A.,Anhanguera-Uniderp University | Santos E.T.,Anhanguera-Uniderp University
Brazilian Journal of Biology | Year: 2011

The Pantanal hydrological cycle holds an important meaning in the Alto Paraguay Basin, comprising two areas with considerably diverse conditions regarding natural and water resources: the Plateau and the Plains. From the perspective of the ecosystem function, the hydrological flow in the relationship between plateau and plains is important for the creation of reproductive and feeding niches for the regional biodiversity. In general, river declivity in the plateau is 0.6 m/km while declivity on the plains varies from 0.1 to 0.3 m/km. The environment in the plains is characteristically seasonal and is home to an exuberant and abundant diversity of species, including some animals threatened with extinction. When the flat surface meets the plains there is a diminished water flow on the riverbeds and, during the rainy season the rivers overflow their banks, flooding the lowlands. Average annual precipitation in the Basin is 1,396 mm, ranging from 800 mm to 1,600 mm, and the heaviest rainfall occurs in the plateau region. The low drainage capacity of the rivers and lakes that shape the Pantanal, coupled with the climate in the region, produce very high evaporation: approximately 60% of all the waters coming from the plateau are lost through evaporation. The Alto Paraguay Basin, including the Pantanal, while boasting an abundant availability of water resources, also has some spots with water scarcity in some sub-basins, at different times of the year. Climate conditions alone are not enough to explain the differences observed in the Paraguay River regime and some of its tributaries. The complexity of the hydrologic regime of the Paraguay River is due to the low declivity of the lands that comprise the Mato Grosso plains and plateau (50 to 30 cm/km from east to west and 3 to 1.5 cm/km from north to south) as well as the area's dimension, which remains periodically flooded with a large volume of water.

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