Carlos R. Padovani

Evaluation of the Siltation of River Taquari, Pantanal, Brazil, through 210Pb Geochronology of Floodplain Lake Sediments

This work presents the 210Pb geochronology of seven bottom sediment cores, collected in three floodplain lakes located in the area of the middle Taquari River, Pantanal, Brazil. In five of them, a significant increase in the sediment mass deposition rate was observed, reflecting an increase of the sediment input to the Pantanal. Additionally, in order to validate the 210Pb results, the mercury content was determined for two sediment cores, showing that despite a constant concentration, the flux of Hg has increased due to an increase in the mass sedimentation rate. This increase can be attributed to the expansion of agricultural activity in the upper Taquari River during the last 25 years.

Avulsive Rivers in the Hydrology of the Pantanal Wetland

This chapter presents and discusses the avulsive nature of the Pantanal rivers and shows how the ever-changing drainage network influences the surface hydrology and ecology. Besides, the systemic portrait here outlined provides new insights concerning the Pantanal hydrodynamics, in its particularities and as a whole system. A simple model of the avulsion process is illustrated, and several realistic examples of the processes leading to river avulsions are shown and discussed. The north-to-south flood-pulse wave due to the presence of bottlenecks is further described in detail. This systemic approach allows identifying that the fluvial “avulsive and bottleneck” dynamics seasonally affects both local and regional ecohydrological processes. Moreover, it shows that avulsive processes are commonplace in Pantanal, and changes in land use, particularly in river headwaters in the highlands, accelerate the avulsions, making the sustainable use of the Pantanal lowland areas difficult.

Use of MODIS Images to Quantify the Radiation and Energy Balances in the Brazilian Pantanal

MODIS images during the year 2012 were used for modelling of the radiation and energy balance components with the application of the SAFER algorithm (Simple Algorithm for Evapotranspiration Retrieving) in the Brazilian Pantanal area. Pixels from the main sub-regions of Barao de Melgaco (BR), Paiaguas (PA) and Nhecolândia (NH) were extracted in order to process microclimatic comparisons. In general, the net radiation (Rn) relied much more on the global solar radiation (RG) levels than on water conditions and ecosystem types, in accordance with the low Rn standard deviation values. The fraction of the available energy used as latent heat flux (λE) were, on average, 65, 50 and 49% for the BR, PA and NH sub-regions, respectively. Horizontal heat advection, identified by the negative values of sensible heat flux (H), made several pixels with λE values higher than those for Rn in the middle of the year. Taking the evaporative fraction (Ef) as a surface moisture indicator, the Tree-Lined Savanna (TLS) was considered the moister ecosystem class, with 58% of the available energy being used as λE, while the driest one was the modified ecosystem Anthropogenic Changes (AC), presenting a λE/Rn fraction of 0.46. According to the spatial and temporal consistencies, and after comparisons with other previous point and large-scale studies, the SAFER algorithm proved to have sensibility to quantify and compare the large-scale radiation and energy balance components in the different ecosystems of the Brazilian Pantanal. The algorithm is useful for monitoring the energy exchange dynamics among the different terrestrial and aquatic ecosystem types throughout the seasons of the year.

Relationships between variability in precipitation, river levels, and beef cattle production in the Brazilian Pantanal

The hydrology of the Brazilian Pantanal, part of the largest humid tropical area on the planet, follows the rhythm of seasonal floods. The traditional movement of cattle herds in the southern Pantanal is defined by these seasonal flooding patterns, which determine the availability and quality of native-grass pastures throughout the year. Extreme hydrological events, such as prolonged droughts and intense floods, can impact the management of cattle in this region, preventing access to, circulation within, and occupation of some grazing areas. This study aims to analyze the spatial and temporal variability of precipitation, the river levels in this region from 1974 to 2012, and assessed the effects on the evolution of local beef cattle stocks. We integrated the spatiotemporal variability of precipitation and river levels for six gaging stations and standardized these variables using standard deviation and linear trends at annual and seasonal scales. Additionally, we integrated the results with an analysis of the livestock production within the region’s municipalities. Regional precipitation was highly variable, including an almost decadal oscillation, with positive trends in parts of the 1970s and 1980s and a negative trend since the 1990s. River levels in the northern portion of the basin and in the Paraguay River corresponded to those dynamics while presenting marked anomalies. Simultaneously, river levels in the eastern Pantanal changed from negative to positive anomalies, which were more intense in wet months. Both the eastern and western patterns reflected the occurrence of extreme El Niño–Southern Oscillation events and other large-scale climatic patterns. In intra-annual terms, the variability of the river levels during the flooded months at four of the six gaging stations studied suggests an early onset or delay of the flood season, as well as positive anomalies in the ebbing months and in the southeast. Given the lags in flow between different rivers in the region, this behavior draws attention to dam construction and intensification of localized flooding in the southern areas, which may impact everyday life and cattle management. For example, from 2009 to 2012, two severe droughts and an extreme flood significantly impacted livestock numbers in the region. Overall, herd numbers decreased (increased) in humid (dry) periods, including a reduction of over 1 million head during the flood of 1973–1974. The differential level patterns at annual, wet season, and dry season between the eastern and western sides of the Pantanal modulate the livestock activities, where the strong negative anomalies of the levels along the eastern side seem to force the diminution of beef cattle stock at local regions in different intensities in annual scale. This reinforces the effects of climate variability and extreme hydrological events on the management and dynamics of the beef cattle industry and market in Brazil.

PolyWaTT: A polynomial water travel time estimator based on Derivative Dynamic Time Warping and Perceptually Important Points

Abstract Traditional methods for estimating timing parameters in hydrological science require a rigorous study of the relations of flow resistance, slope, flow regime, watershed size, water velocity, and other local variables. These studies are mostly based on empirical observations, where the timing parameter is estimated using empirically derived formulas. The application of these studies to other locations is not always direct. The locations in which equations are used should have comparable characteristics to the locations from which such equations have been derived. To overcome this barrier, in this work, we developed a data-driven approach to estimate timing parameters such as travel time. Our proposal estimates timing parameters using historical data of the location without the need of adapting or using empirical formulas from other locations. The proposal only uses one variable measured at two different locations on the same river (for instance, two river-level measurements, one upstream and the other downstream on the same river). The recorded data from each location generates two time series. Our method aligns these two time series using derivative dynamic time warping ( DDTW ) and perceptually important points ( PIP ). Using data from timing parameters, a polynomial function generalizes the data by inducing a polynomial water travel time estimator, called PolyWaTT . To evaluate the potential of our proposal, we applied PolyWaTT to three different watersheds: a floodplain ecosystem located in the part of Brazil known as Pantanal, the worlds largest tropical wetland area; and the Missouri River and the Pearl River, in United States of America. We compared our proposal with empirical formulas and a data-driven state-of-the-art method. The experimental results demonstrate that PolyWaTT showed a lower mean absolute error than all other methods tested in this study, and for longer distances the mean absolute error achieved by PolyWaTT is three times smaller than empirical formulas.

Analysis and distribution of the rainfall monitoring network in a Brazilian Pantanal Region.

ABSTRACT: To better understand drought and flood dynamics in the Pantanal is crucial an adequate hydrometeorological monitoring network. However, few studies have investigated whether the current monitoring systems are suitable in this region. Here, we analyzed the hydrometeorological monitoring network of the Aquidauana region, composed of pluviometric, meteorological and fluviatile gauging stations. We obtained data of all hydrometeorological gauges available in this region to compare with the World Meteorological Organization (WMO) recommendation. We found that although the number of stations in operation is satisfactory when compared with that established by the WMO, the network is not satisfactory in the operating stations because of lack of maintenance, thus creating a need for additional stations. This fact was also observed when analyzing the meteorological network. Using remote sensing data may be possible to fill these data gap. However, to improve the knowledge on hydrological processes in this region is still necessary to install additional ground-based stations. RESUMO: Para entender melhor a dinâmica de seca e inundacao no Pantanal e fundamental uma rede de monitoramento hidrometeorologico adequada. No entanto, poucos estudos tem investigado se os atuais sistemas de monitoramento sao adequados nesta regiao. Aqui, analisamos a rede de monitoramento hidrometeorologico da regiao de Aquidauana, composta por estacoes pluviometricas, meteorologicas e fluviais. Obtivemos dados de todos os medidores hidrometeorologicos disponiveis nesta regiao para comparacao conforme a recomendacao da Organizacao Meteorologica Mundial (OMM). Constatou-se que, embora o numero de estacoes em operacao seja satisfatorio quando comparado com o estabelecido pela OMM, a densidade da rede nao e satisfatoria nas estacoes de operacao por falta de manutencao, criando assim a necessidade de estacoes adicionais. Esse fato tambem foi observado na analise da rede meteorologica. O uso de dados de sensoriamento remoto pode ser possivel para preencher essa lacuna de dados. No entanto, para melhorar o conhecimento sobre os processos hidrologicos nesta regiao ainda e necessario instalar estacoes terrestres adicionais.