Rodrigo Cauduro Dias de Paiva

• Federal University of Rio Grande do Sul

The increase in atmospheric CO2 concentration elevates atmospheric temperature and enhances water storage capacity. This could lead to more extreme precipitation events, while simultaneously, higher temperatures may cause land and soil to dry out. Such alterations create ambiguous expectations regarding the direction of hydrological changes in the...

Climate change is expected to increase the frequency and intensity of flooding, emphasizing the need to better understand these events. Satellite observations provide essential information, and the recent launch of SWOT offers new opportunities to investigate flood dynamics. Here, we use SWOT observations to detect significant hydrologic changes du...

In late 2023, the Amazon River Basin experienced its most extreme drought, putting its population and ecosystem at major risks. Gauges that were still functioning measured the lowest river water levels (RWL) on record. Here, satellite observations, including Surface Water Ocean Topography (SWOT), reveal the spread and timing of extremely low RWL ac...

Inflow prediction on sub-seasonal timescale have the potential for important contributions to the management of water resources in hydroelectric dam operations. These forecasts challenge the limitations of the medium-term and extend it, bridging a long-standing technical-scientific gap in the forecasting field. In Brazil, the use of sub-seasonal hy...

A simple analytical model was developed for evaluating the attenuation of flood wave peak discharge. The physically‐based model represents the flood wave along its trajectory, based on the diffusive model. Relative peak discharge decreases along the downstream distance according to a power function. The distance is scaled by the attenuation factor...

This book is about simple methods that are used to obtain reference streamflow data at ungauged points on rivers and streams, using data from neighbouring gauge stations. It shows how the methods are applied in practice, with example applications. Furthermore, the book gives information on the probable uncertainty of the resulting streamflow esti...

O livro Hidrologia da Amazônia vista do espaço: avanços científicos e desafios futuroso é uma tradução do artigo de revisão não sistemática publicado em 2021 na Review of Geophysics (https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020RG000728). O livro apresenta uma extensa revisão das conquistas de mais de três décadas de avanços científicos...

Study region: The Congo River basin (CRB), the world's second-largest river system, is subject to extreme hydrological events that strongly impact its ecosystems and population. Study focus: Here we present an improved 40-year (1981-2020) hydrological reanalysis of daily CRB discharge and analyze the spatiotemporal dynamics of recent major CRB floo...

Evapotranspiration (ET) is a key process linking surface and atmospheric energy budgets, yet its drivers and patterns across wetlandscapes are poorly understood worldwide. Here we assess the ET dynamics in 12 wetland complexes across South America, revealing major differences under temperate, tropical, and equatorial climates. While net radiation i...

Climate scenarios are important information for water planning, but, in some cases, they disagree with recent climate alterations, which affects their robustness and reliability. Robustness evaluation can help identifying areas that should be prioritized by in water sector adaptation to climate change. Although crucial, this kind of analysis has be...

Study region: South America large basins (>5000 km 2) Study focus: This work represents a first assessment of seasonal streamflow forecasts in South America based on a continental-scale application of a large scale hydrologic-hydrodynamic model and ECMWF's seasonal forecasting system precipitation forecasts (SEAS5-SSF) with bias correction. Seasona...

We provide a new dataset of simulated suspended sediment discharge for South American rivers using daily hydrologic-hydrodynamic modeling. From the previous version (10.17632/k7c5482fsm.1) we improved our results by simulating 234 large reservoirs in South America and also by considering 8 land use and land cover maps. We also extended our simulate...

River sediment fluxes have been impacted in South America (SA), one of the continents with the highest erosion and sediment transport rates globally. However, the magnitude and spatio‐temporal distribution of the main drivers of changes have been poorly identified and explored. Here, we performed simulations using a hydrological‐hydrodynamic‐sedime...

Due to the frequent occurrence of extreme hydrological events in the South American rivers, this work aims to develop a hydrological monitoring platform open to the public, with a wide and intuitive access, using resources of an online geographic information system, in order to contribute to a better understanding of the behavior of these natural d...

Streamflow forecasts from continental to global scale hydrological models have gained attention, but their performance against operational forecasts at local to regional scales must be evaluated. This study assesses the skill of medium-range, weekly streamflow forecasts for 147 large Brazilian hydropower plants (HPPs) and compares their performance...

Current forecasts estimate that almost 68% of the global population will be living in urban centers by 2050. As a result, the increase in impermeable surface area can result in severe hydrological impacts, such as the increase in surface runoff and the frequency of floods and their magnitude. Thus, this work analyzes the performance of the hydrodyn...

Palavras-Chave-Estimativa de precipitação quantitativa, Sensoriamento remoto, Desastres hidrológicos. INTRODUÇÃO A precipitação é um dos principais processos do ciclo hidrológico e pode desencadear eventos extremos, como inundações e movimentos de massa. As alterações climáticas podem tornar os eventos extremos ainda mais frequentes, assim o monito...

Climate change can affect all levels of society and the planet. Recent studies have shown its effects on sediment fluxes in several locations worldwide, which can impact ecosystems and infrastructure such as reservoirs. In this study, we focused on simulating sediment fluxes using projections of future climate change for South America (SA), a conti...

Extensive floodplains throughout the Amazon basin support important ecosystem services and influence global water and carbon cycles. A recent change in the hydroclimatic regime of the region, with increased rainfall in the northern portions of the basin, has produced record-breaking high water levels on the Amazon River mainstem. Yet, the implicati...

A warmer atmosphere is able to hold more water which consequently intensifies the hydrological cycle. The projected increase in extreme precipitation has been associated with greater floods; however, most recent studies have argued that the reduced soil moisture could be causing the opposite effect. We aim to understand how the hydrometeorological...

Sediment flows dynamics (erosion, transport and deposition) have been disrupted in South America (SA), a continent with the highest erosion and sediment transport rates globally. However, the magnitude and spatial distribution of the main drivers of changes have been poorly identified and explored. Here, we performed simulations using a hydrologica...

The estimation of reference flows in the dry period in places without data is necessary for the management of water resources. Different techniques are used for this, and normally they are based on some kind of extrapolation from data collected in fluviometric stations with relatively long observed series (20 years or more). Some authors suggest th...

Brazil hosts a large amount of freshwater. Knowing how this stored water is partitioned in space and time between surface and subsurface components is a crucial step towards a more correct depiction of the country’s water cycle, which has major implications for decision making related to water resources management. Here, we extracted monthly water...

Os reservatórios são estruturas feitas pelo homem que tem contribuído para a redução dos sedimentos em diversos trechos de rios e consequentemente para os oceanos. O objetivo deste trabalho foi avaliar a performance de um modelo de sedimentos continental em representar os fluxos de sedimentos em suspensão e de leito, considerando a presença de 234...

In this work, the role of the initial conditions (ICs) and boundary conditions (BCs) on the predictability of natural flows of large basins rivers (>1000km²) in South America from the MGB-SA (South American Large Basins Model) was investigated. We proposed an analysis based on a simple metric: predictability was estimated by the number of days the...

The Amazon River basin harbors some of the world's largest wetland complexes, which are of major importance for biodiversity, the water cycle and climate, and human activities. Accurate estimates of inundation extent and its variations across spatial and temporal scales are therefore fundamental to understand and manage the basin's resources. More...

The HEC-RAS software reaches its 6.0.0 version in May of 2021, introducing new computational tools to its users. Among these new tools, HEC-RAS is capable of simulating spatially varied rain and evaporation data by grid, constant values or table format. A 2D Sinos river model was created with the intent of testing mainly these two new tools. The Si...

Global and regional climate models (GCM and RCM respectively) are the current mathematical tools used to project alterations on precipitation regimes given different greenhouse gases emissions scenarios. However, these models have specific resolutions, physical equations and numerical approaches that provide a diverse set of performances across dif...

The estimation of reference flows, either the average flow or Q95, in ungauged locations data is necessary for water resources management. The present work presents an evaluation of errors resulting from the application of the specific flow transfer method (or drainage area ratio), a simple and widespread technique, for which there is a lack of rep...

Evapotranspiration (ET) connects the land to the atmosphere, linking water, energy, and carbon cycles. ET is an essential climate variable with a fundamental importance, and accurate assessments of the spatiotemporal trends and variability in ET are needed from regional to continental scales. This study compared eight global actual ET datasets (ETg...

Mapping flood risk areas is important for disaster management at the local, regional, and national scales. The aim of this study was to evaluate the ability of large-scale models to obtain flood hazard maps. The models were compared to the estimates developed by the Brazilian Geological Survey (CPRM) for different return periods (RP). The floods we...

This study intends to integrate heterogeneous remote sensing observations and hydrological modeling into a simple framework to monitor hydrological variables in the poorly gauged Congo River Basin (CRB). It focuses on the possibility of retrieving effective channel depths and discharges all over the basin in near real time (NRT). First, this paper...

Proposed hydropower dams at more than 350 sites throughout the Amazon require strategic evaluation of trade-offs between the numerous ecosystem services provided by Earth’s largest and most biodiverse river basin. These services are spatially variable, hence collective impacts of newly built dams depend strongly on their configuration. We use multi...

Cette étude a pour but d'intégrer des observations hétérogènes de télédétection et la modélisation hydrologique dans un cadre simple pour le suivi des variables hydrologiques dans le bassin du fleuve Congo (CRB), qui est peu jaugé. Elle se concentre sur la possibilité d'estimer les profondeurs et les débits effectifs des rivières sur l'ensemble du...

Satellite observations offer invaluable insights into hydrological processes and environmental change in the Amazon. The Amazon Basin is the largest river basin in the world. It covers roughly six million square kilometers, which is about one third of South America. While the sheer scale and difficulty of access makes field observations challengin...

This report summarises the main results, conclusions and recommendations of the “HYDROSPACE-GEOGLOWS 2021” Workshop organised by the European Space Agency (ESA), in collaboration with the French Space Agency (CNES) and the GEO Global Water Sustainability Initiative (GEOGloWS) (Fig. 1). This Workshop is a sequel to the ones held in Toulouse (F) in 2...

Reservatórios tem sido um tema central em diversos assuntos atuais como crise hídrica, geração de energia, retenção de sedimentos, redução da conectividade de rios e impacto nos ecossistemas. O objetivo do presente trabalho foi estimar pela primeira vez a vida útil dos grandes reservatórios da América do Sul, buscando compreender o impacto dos rese...

As the largest river basin on Earth, the Amazon is of major importance to the world's climate and water resources. Over the past decades, advances in satellite‐based remote sensing (RS) have brought our understanding of its terrestrial water cycle and the associated hydrological processes to a new era. Here, we review major studies and the various...

Numerous hydropower facilities are under construction or planned in tropical and subtropical rivers worldwide. While dams are typically designed considering historic river discharge regimes, climate change is likely to induce large-scale alterations in river hydrology. Here we analyze how future climate change will affect river hydrology, electrici...

Hydrological models are useful tools for water resources studies, yet their calibration is still a challenge, especially if aiming at improved estimates of multiple components of the water cycle. This has led the hydrologic community to look for ways to constrain models with multiple variables. Remote sensing estimates of soil moisture are very pro...

In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and mo...

In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and mo...

Reservoirs considerably affect river streamflow and need to be accurately represented in environmental impact studies. Modeling reservoir outflow represents a challenge to hydrological studies since reservoir operations vary with flood risk, economic and demand aspects. The Brazilian Interconnected Energy System (SIN) is an example of a unique and...

Probabilistic hydrological forecasting and ensemble techniques have leveraged streamflow prediction at regional to continental scales up to several weeks in advance. However, ensembles that only account for meteorological forecast uncertainty are typically biased and subject to dispersion errors, thus limiting their use for rational decision-making...

In Brazil, substantial understanding of flooding regimes in large natural wetlands, as in the Amazon and Pantanal regions, has been promoted through remote sensing (RS) and river flood modeling. However, less research attention has been given to the floods with socioeconomic impacts. In the last decades, RS has provided new opportunities for improv...

As the largest river basin on Earth, the Amazon is of major importance to the world's climate and water resources. Over the past decades, advances in satellite-based remote sensing (RS) have brought our understanding of its terrestrial water cycle and the associated hydrological processes to a new era. Here, we review major studies and the various...

Evapotranspiration (ET) is a key process linking surface and atmospheric energy budgets, yet its drivers and patterns across wetlandscapes are poorly understood worldwide. Here we assess the ET dynamics in 12 wetlands complexes across South America, revealing major differences under temperate, tropical, and equatorial climates. While net radiation...

The accuracy of hydrological model predictions is limited by uncertainties in model structure and parameterization, and observations used for calibration, validation and model forcing. While calibration is usually performed with discharge estimates, the internal model processes might be misrepresented, and the model might be getting the "right resu...

Suspended sediments (SSs) contribute to the maintenance of several ecosystems. However, intense soil erosion can lead to environmental, social, and economic impacts. South America (SA) has very high erosion and sediment transport rates. Here, we present a detailed description of the spatio‐temporal dynamics of natural SS flows in SA using the conti...

Estimating discharges is a major challenge in water resources management, and techniques such as Data Assimilation (DA) can be used to improve these estimates. This study assesses the application of the local ensemble Kalman filter (LEnKF) DA scheme within a large scale hydrological-hydrodynamic model to improve discharge estimates. Different scena...

River floodplains and reservoirs interact throughout a basin drainage network, defining a coupled human-water system with multiple feedbacks. Recent modeling developments have aimed to improve the representation of such processes at regional to continental scales. However, most large-scale hydrological models adopt simplified lumped reservoir schem...

We provide a dataset of simulated suspended sediment discharge for South America rivers using daily hydrologic-hydrodynamic modeling. We simulate the potential natural situation, where rivers is no damming, and therefore, sediment are not trapped. The model MGB-SED AS was calibrated and validated against 595in-situ sediment stations from three nati...

Sediment flows in South America supported by daily hydrologic‐hydrodynamic modeling

The discretization of river networks is a critical step for computing flow routing in hydrological models. However, when it comes to more complex hydrologic-hydrodynamic models, adaptations in the spatial representation of model calculation units are further required to allow cost-effective simulations, especially for large scale applications. The...

Terrain elevation is essential for land management, navigation, and earth science applications. Remote sensing advancements have led to an increase in the availability of a range of digital elevation models with global to quasi-global land coverage. However, the generation of these models in water bodies requires specialized approaches , such as th...

Global estimates of river dynamics are necessary to manage water resources, mainly in developing countries where in-situ observation is limited. Remote sensors such as nadir altimeters can complement ground data. However current altimeters miss a large number of continental surface water bodies, what is expected to be surpassed by the future Surfac...

In this paper we synthesize the special sessions of the XXIII Brazilian Water Resources Symposium 2019 in order to understand the major advances and challenges in the water sciences in Brazil. We analyzed more than 250 papers and presentations of 16 special sessions covering topics of Climate Variability and Change, Disasters, Modeling, Large Scale...

Global estimates of river dynamics are needed in order to manage water resources, mainly in developing countries where in-situ observation is limited. Remote sensors such as nadir altimeters can complement ground data. Current altimeters miss however a large number of continental surface water bodies. This issue will be largely resolved by the futu...

This study presents an alternative model for hydrological tracking of surface waters designed to investigate multi‐year storage and movement of water in large river basins. We coupled this model with a background solution from a large‐scale hydrological‐hydrodynamic model to study the fate of waters in the Amazon River basin (6 million km2) conside...

We introduce a new catchment dataset for large-sample hydrological studies in Brazil. This dataset encompasses daily time series of observed streamflow from 3679 gauges, as well as meteorological forcing (precipitation, evapotranspiration, and temperature) for 897 selected catchments. It also includes 65 attributes covering a range of topographic,...

Recent years have seen the development of 1D and 2D regional scale hydrological-hydrodynamic models, which differ greatly from reach scale applications in terms of subgrid assumptions, parameterization and applied resolution. Although 1D and 2D comparisons have already been performed at reach and local scales, model differences at regional scale ar...

In this research study, the MGB-IPH (acronym for Large Scale Model in Portuguese - Modelo de Grandes Bacias) was used to simulate the propagation of a dam breach hydrograph estimated from predictor equations for the Três Marias Hydropower Dam, considered one of the largest in South America. The results of the peak flow, peak time and flood spot wer...

Recent scientific and computational developments have pushed hydrological forecasting systems up to continental and global scales. In this study, we evaluate the potential skill of ensemble streamflow forecasts for flood prediction in South America (SA), with a closer look on some of the large basins of the continent. Medium-range precipitation for...

Topography is critical information for water resources management in lakes, and remote sensing provides a unique opportunity to estimate topography in ungauged regions. We introduce here a new method that estimates nearshore topography of water bodies based on a flood frequency map and time series of water levels by assuming the equivalence between...

Animated GIF of daily rainfall in South America during the 1983 year.

Animated GIF of return period of daily discharges in South American rivers during the 1983 year.

Terrain elevation data are essential for land management, navigation, and earth science applications. Digital elevation models (DEMs) can be created for land as well as underwater surfaces, and remote sensing advancements have led to the increase in the availability of a range of DEMs over the land. However, the generation of underwater DEMs usuall...

Abstract. We introduce a new catchment dataset for large-sample hydrological studies in Brazil. This dataset encompasses daily time series of observed streamflow from 3713 gauges, as well as meteorological forcing (precipitation, evapotranspiration and temperature) for 897 selected catchments. It also includes 63 attributes covering a range of topo...

Topography is critical information for water resources management in lakes, and remote sensing provides a unique opportunity to estimate it in ungauged regions. We introduce here a new method which estimates near shore topography of water bodies based on a flood frequency map and time series of water levels by assuming the equivalence between flood...

South America contributes to roughly 30% of global runoff to the oceans. Because the regional economy and biodiversity depend significantly on its water resources, assessing potential climate change impacts on the continental water balance is crucial to support water management planning. Here we evaluate the mean alterations of water balance variab...

Tens of thousands of dams were built around the world to reduce flood risks, produce energy, and maximize benefits of limited freshwater resources. In Brazil, the main and largest reservoirs are related to hydropower plants. Improving the understanding of reservoir dynamics is important not only to evaluate their impact in the flow regime of Brazil...

This study provides a spatio-temporal analysis of the great floods that occurred in South America in 1983 using hydrometeorological data and outputs from a continental-scale hydrological-hydrodynamic model. In the extreme year 1983, there were three main flooding periods (February, June and July) in many South American river basins, such as the Ara...

Sediment models are important for estimating soil erosion, sediment transport, and deposition at different scales and for disparate scenarios; however, the availability of in-situ measurements may not be sufficient for the appropriate evaluation of model performance. For this reason, this study investigated how surrogate data (water quality [WQ] an...

South America (SA) features a wide range of hydroclimatic characteristics, contributing to around 30 % of global runoff to the oceans. Managing water resources in SA is challenging due to many reasons including the complexity of its river systems, conflicts of water uses extending beyond political borders and extreme hydrometeorological events occu...

Tropical basins such as the Amazon basin are the main sources of dissolved solids for the oceans, but they lack of studies that involve the sediment modeling, whereas the application of mathematical models that estimate the erosion and transport of sediments on rivers with adequate temporal and spatial distribution. The flood routing module in hydr...

Considering the past, it has been observed that since the 1950s, there have been documented 39 cases of dam failure in Brazil. Considering the present, in 2019 Brazil experiences the most catastrophic dam break ever documented, in terms of confirmed victims (Brumadinho). For the future, it is estimated that the probability of having at least 1 dam...