Revista de Gestão de Água da América Latina (Water Management Journal in Latin America)

NATURAL AND ANTHROPIC EFFECTS ON THE QUALITATIVE ASPECTS OF WATER IN THE NIQUIM RIVER BASIN

2024-12-19T11:08:43-03:00

The natural and anthropogenic effects on the water quality of the Niquim River, located in the São Miguel Hydrographic Region, were analyzed with the aim of developing a classification proposal. Qualitative water monitoring was carried out in the Niquim River Lagoon (RNL), the second near the city's water intake (RNC) and the third near the mouth (RNF). The results of the analyses were compared with the limits established by CONAMA Resolution No. 357/05. In the classification proposal, the basin was divided into 3 sections, for which classes 1 and 2 were suggested, but it was found that some parameters do not meet their predominant uses. In section 1, the aim is to increase DO and reduce BOD_5,20 and ammoniacal N, through the preservation of forest formations to reduce the organic load in this section. In section 2, it is necessary to reduce the BOD_5.20 and ammonia-N parameters by preserving vegetated areas, mainly riparian forests, to reduce the organic load in this section. In section 3, the BOD_5.20, ammonia-N, DO and E. coli parameters are above the levels established in the Resolution. In order to reach the limits of the proposed classification in all sections, it is necessary to correctly dispose of effluents, preserve green areas, and plan land use and occupation.

Changes in Water Color Related to Mining in Rivers of Southwestern Amazon Observed by Satellite

2025-01-21T10:45:13-03:00

Given the importance of water resources, their monitoring is essential. Considering the size of Brazilian river basins, especially the Amazonian ones, the use of remote sensing tools becomes feasible, allowing for the monitoring of surface water quality, particularly color characteristics and total solids. The components present in the water alter its reflectance according to their characteristics, enabling the study and tracking of water quality. The main objective of this work was to identify changes in the water color of rivers in the Southwestern Amazon, within the sub-basins of the Ji-Paraná, Canumã, and Amaná rivers, mapping evidence of interactions and the impacts of mining and gold panning. This was achieved through reflectance angles and dominant wavelengths, understanding the formation of water color in the basins and the influence of mining and human activities. A statistical analysis of the average values of dominant wavelengths and suspended material data provided by ANA was conducted to verify whether the variations were significant between 1994 and 2021. Through statistical analyses, significant changes were demonstrated for higher average dominant wavelengths in most sections of the Ji-Paraná and Amaná basins, while for the Canumã River, the changes were mostly toward shorter wavelengths.

A MULTIOBJECTIVE AND MULTICRITERIA METHODOLOGY FOR SUPPORT TO THE PROCESS OF CONCESSION OF WATER USE RIGHTS

2025-02-21T11:39:49-03:00

We proposed a methodology to assist in the granting of water use rights, using multi-objective and multi-criteria methods, and its application to the Preto River basin. We divided the basin into five zones, and we identified water demands and availability in them. We defined eight different development scenarios for the basin, taking into account aspects such as the location of irrigators in the basin, the type of irrigator, and their growth rate. From the interviews with experts, we established seven criteria, covering environmental, social, technical, and economic aspects. We evaluated these criteria using GIS and water balance using Acquanet. We applied three multi-objective methods (Compromise Programming - CP, PROMÉTHÉE-II, and TOPSIS) to four different sets of weights, defined by consulting experts and simulating “policies” to guide the granting process in the Preto River basin. The “policies” aimed to give priority to social, environmental, and economic aspects, in addition to a “neutral policy,” with all weights equal. The results for the different “policies”, after being normalized, produced an aggregated classification and established the concession scenario to be implemented in the basin. The methodology made it possible to define a water granting policy capable of considering conflicts and articulated with social policies.

MINEIRO WATER RESOURCES POLICY

2025-01-21T10:50:22-03:00

The management of Brazilian water resources is conducted through a system that possesses a holistic perspective on all aspects involving water management. Additionally, this system seeks to reconcile strategically important sectors of the country for the sake of water management. Minas Gerais is a state that plays a crucial role in the country when considering economic, social, and environmental aspects. Thus, understanding the water resources management system in Minas Gerais is fundamental for achieving cohesion in the management process at the national level. That said, this study evaluates the relationship between the water resources regulations in force at the aforementioned levels, traversing certain fields of water management in Minas Gerais and Brazil. It is evident that Minas Gerais plays a significant role in the management of water resources under its jurisdiction.

Use and occurrence of 2,4-D in Brazil: emphasis on drinking water quality

2025-01-21T16:19:42-03:00

This study aims to provide a diagnosis of 2,4-D in Brazil, based on its environmental fate, sales, spatial distribution, and concentrations in raw and drinking water. An estimate of 2,4-D sales in Brazilian municipalities and states was conducted, considering data on planted area, sales, and authorized use in the country. The concentration of 2,4-D was analyzed through a systematic literature review and data processing from SISAGUA. It was found that 2,4-D shows a tendency for increased commercialization, with an annual average of 43,267 tons and an average usage rate per planted area of 0.65 kg/ha, with some notable regions. 2,4-D showed a high detection frequency, with values that, overall, did not exceed the maximum acceptable value (MAV) for drinking water in Brazil. It is concluded that 2,4-D is widely used and detected, however, this fact does not currently reflect a risk to human health through drinking water consumption.

Influence of seasonality on the characteristics and biological pre-treatment of landfill leachate

2025-02-19T15:33:23-03:00

Factors such as climate, waste characteristics, age and operation of the landfill influence the flow and composition of landfill leachate, which must be monitored as they interfere with the treatment process. Although anaerobic and aerated lagoons are unable to bring the treated leachate into line with release standards, they function as pre-treatment and amortise its variability, preparing it for post-treatment. This study assessed the influence of seasonality on the flow, composition and biological pre-treatment of leachate generated in a landfill in a tropical region, by means of physico-chemical and flow analyses of the raw and pre-treated leachate. The influence of precipitation on the increase in flow and the variability of COD and BOD was confirmed5,20. Pre-treatment removed 60.8% and 36.6% of COD; 74.7% and 79.4% of BOD5.20, and 94.6% and 76.8% of N-NH4, respectively, in the dry and rainy seasons, but with remaining concentrations still high for direct use in post-treatment.

Challenges for effective implementation of urban drainage and stormwater management service fees in Brazil

2025-02-19T15:15:01-03:00

Intense urbanization alters the water balance and impacts stormwater runoff, making Urban Stormwater Drainage and Management (USDM) services essential to mitigate the effects of heavy rainfall. This article analyzes the economic and financial situation of USDM services in Brazil based on data from the National Sanitation Information System (2015-2022) and addresses legal, institutional, and technical challenges for implementing an efficient charging system. A simplified financing model adaptable to various cities and regions is also proposed. The results show that of the 24 municipalities claiming to charge for USDM services, only one actually does. These services are mostly provided by direct public administration, with funding for maintenance, operation, and system expansion primarily coming from the general budget. While implementing charges could enhance service delivery, restructuring the institutions responsible for USDM is also necessary.

NEW PATHWAYS FOR SUSTAINABLE URBAN WATER MANAGEMENT

2025-03-21T14:55:53-03:00

Accelerated urbanization and climate change intensify the challenges of sustainable urban water management, particularly in emerging and low-income economies. In these regions, recent unplanned urbanization and insufficient or inadequate infrastructure increase population vulnerability to extreme events. The concept of sustainable urban water management has historically evolved under various terminologies—BMP, LID, SUDS, WSUD, Green Infrastructure, and Sponge Cities—reflecting different priorities and cultural contexts. Recently, it has been framed under the new term Nature-Based Solutions (NBS). Urban water management encompasses seven essential components: drainage, detention, retention, infiltration, evaporation, treatment, and reuse. Incorporating as many of these components as possible into stormwater systems ensures sustainable urban water management, fostering resilience and adaptation in cities facing climate change challenges. Additionally, integrating gray infrastructure with technological components and natural elements is a crucial step toward achieving sustainability in these systems, while also providing essential ecosystem services. This study presents a conceptual review of sustainable urban water management, outlining its components, requirements, and steps for implementation. It emphasizes the importance of multidisciplinary approaches and strong community involvement in these initiatives. Furthermore, it highlights the need to strengthen regulatory and financial frameworks to encourage the adoption of the necessary measures for achieving sustainable urban water management.

Control of surface runoff at different scales in an urban community through event-based and continuous simulations

2025-04-25T15:37:12-03:00

Green and blue infrastructures integrate ecosystem-based measures into urban planning to mimic the natural water cycle, controlling runoff at its source and reducing peak flows. However, their implementation in consolidated urban communities can face challenges due to limited space and socioeconomic constraints, which hinder installation and maintenance. In this context, this study evaluated the performance of runoff control devices in the Grota do Cigano sub-basin (SBGC), an urban community in Maceió-AL, using SWMM to calibrate a hydrological-hydraulic model for the current scenario, which has a critical overflow point at its outlet, and simulating four intervention scenarios. In scenarios I and II, detention microrreservoirs (MRD) were simulated in residential lots, while in scenarios III and IV, detention reservoirs (RD) were simulated near the outlet. In scenarios I and III, the devices were sized based on the drainage channel capacity, whereas in scenarios II and IV, they were designed according to pre-urbanization flow rates. The RD proved to be more viable, effectively controlling runoff across the entire SBGC while occupying less space. Additionally, devices designed based on drainage channel capacity were more practical, balancing flow control efficiency with minimal space usage.

Origin and background of the barium anomaly in the groundwater of the Barreiro’s Alkaline-Carbonatite Complex – Araxá – MG

2025-04-25T15:45:17-03:00

The anomalous values of barium in the groundwater of the Barreiro’s Carbonatite Alkaline Complex (BACC), located in the municipality of Araxá, in the Alto Paranaíba Igneous Province, have been studied since the early 1980s, when this element was detected dissolved in groundwater at high concentrations. The objective of this work is to investigate the possible origins and what levels can be considered natural for barium in the CACB. The methodology used was based on the statistical analysis of monitoring well data to determine the background, as well as geochemical solubility analyses, SEM, and XRD in clay soils to estimate the origin of barium, in addition to the statistical treatment of barium concentrations in soil samples collected XXX. The results of the XRD analyses of the lateritic covers did not detect barium minerals, despite the chemical and solubility analyses showing significant levels of the element. The geochemical solubility analyses of barium from the clays of the lateritic covers show values that can reach 16 mg/L. This condition indicates that barium is probably in the form of free ions (Ba2+), adsorbed on clay minerals and iron oxide-hydroxides, which constitute the capping materials of the alkaline dome, being mobilized from recharge and transported to the saturated zone. The statistical analysis of the results of barium concentrations in groundwater shows that the value of 5.52 mg/L can be adopted as a reference applicable to the background levels of barium in the groundwater of the CACB. The use of groundwater from the interior of the dome should be evaluated with caution for human consumption and recreation, as the maximum permitted values of 0.7 and 1.0 mg/L, respectively, are lower than the defined background value.

PROGRAMA NOVO PINHEIROS. AVANÇAMOS RUMO A REVITALIZAÇÃO DOS RIOS URBANOS BRASILEIROS?

2025-04-09T15:00:48-03:00

As climate change intensifies the frequency and severity of extreme events, the revitalization of urban rivers and the creation of green and blue infrastructure through Nature-Based Solutions (NBS) emerge as a significant opportunity for city adaptation and the construction of more sustainable, resilient, and livable cities for future generations. The rapid urbanization process of the São Paulo Metropolitan Region has resulted in the degradation of its watercourses and the distancing of the population from the water element, which reflected in the current state of its main rivers. The emergence of the "Tietê Program" in the 1990s represents a milestone in the beginning of concern for the recovery of the Tietê River and the movement to achieve this purpose, culminating in various other actions such as the "Novo Pinheiros Program", the subject of the present article. This study aimed to analyze the "Novo Pinheiros Program", an initiative of the Government of the State of São Paulo to recover and revitalize the Pinheiros River. For this purpose, a qualitative analysis of the actions carried out by the program was conducted, as well as an assessment matrix of the actions and their effectiveness in the purpose of recovering and revitalizing the Pinheiros River. Additionally, a comparative analysis of the program's actions with 10 other similar programs was conducted. Thus, the study provides an answer to the central question: "Are we progressing towards the revitalization of Brazilian urban rivers?".

Hidrograma de Projeto em Pequenas Bacias

2025-01-20T22:02:04-03:00

The estimation of the design hydrograph for small basins (< 2,000 km2) is a challenge due to the lack of flow data. The model usually used in this case is the NRSCS (NRSCS, 1975), where one of the main parameters is the CN, which estimates the amount of surface water in the basin. The CN value is estimated based on land use and type, but it brings with it many uncertainties due to the subjectivity of the choice of the CN parameter, leading to uncertainties in the estimated flows.

The proposed procedure uses the maximum average daily flow for the chosen risk (return time), obtained by regionalization of the maximum flows observed in the region, and the precipitation with the same risk to estimate the CN parameter, seeking to minimize the uncertainties of its estimate.

This methodology was applied in the Camboriu River basin (SC) with a drainage area of 127 km2 and a concentration time of 6 hours. The maximum average daily flow for each return time was obtained by regionalization by the Index Flood method (NERC, 1975) based on the data measured from the region. The estimated CN value was obtained based on the referred flow and precipitation for the same risk. This result was compared with the conventional procedure where the CN is obtained by the reference tables of the literature based on its land use. The result obtained based on the maximum regionalized flow tends to be more reliable, since it is based on flow data from the region. This methodology is not recommended when regionalization is unreliable. This can occur for basins smaller than 20 km2 that do not have data and extrapolation by regionalization has uncertainties.

Português português

2025-06-10T16:28:22-03:00

This article aimed to analyze the impacts of climate change effects, associated with rainfall patterns and intensity, on the urban drainage system projects of Joinville/SC. The research evaluated climate projections for global warming scenarios of 1.5°C, 2°C, and 4°C, applied statistical methods to identify trends in historical precipitation data, and compared current design rainfall intensities with newly projected scenarios. Through historical data and future projections, a comparative analysis of hydrological parameters for hydraulic network sizing was also developed. The results indicate a significant increase in rainfall intensity, showing that the city's current drainage system is undersized for both present and future climate conditions. The study underscores the need for sustainable urban planning and public policies to enhance the resilience of urban infrastructure to climate change.

WATER RESOURCES MANAGEMENT IN SANTA CATARINA: EXECUTIVE ENTITIES CASE

2025-07-11T14:11:57-03:00

The Water Resources Management System is centered around river basin committees and water agencies. Until the formal regulation of water agencies, support models such as executive entities have been implemented to assist the committees. This study presents the outcomes of the executive entity for the Eastern Cluster of the State of Santa Catarina for the years 2023 and 2024. During the operational period, 128 meetings were held, resulting in 635 administrative acts and 24 training sessions, which engaged over 1,400 participants. Significant progress was made in the implementation of Water Resources Plans (PRH) and management instruments, including the development of 19 projects and 3 superficial and groundwater quality framework and the implementation programs. The results of the project demonstrated the strengthening of the committees and the advancement of PRH and management instruments. However, certain weaknesses were identified, such as the use of fixed-term contracts within the executive entity model, which can lead to discontinuity in the work.

HYDROLOGICAL RESPONSE OF THE MINAS GERAIS PORTION OF THE SÃO FRANCISCO RIVER BASIN TO RAINFLOW-RUNOUT MODELING

2025-07-24T14:48:35-03:00

Flow forecasting in extreme events caused by intense precipitation is one of the greatest challenges of our time and can help water resource managers in decision-making, minimizing the risks arising from these events. This study aimed to implement the HEC-HMS model in the Minas Gerais portion of the São Francisco River basin. The methods used in the hydrological modeling were: Deficit and Constant, for flow separation; Clark Unit Hidrograph, for hydrograph formation; Recession, for base flow; and Muskingum-Cunge, for flow propagation. The precipitation input data were obtained by the CHIRPS product and the flow data, for calibration and validation, from the fluviometric stations, in Hidroweb. The calibration period was from January 1, 2010 to December 31, 2017, and the validation period was from January 1, 2019 to December 31, 2022, reproducing the main extreme flood events that occurred in recent years. The model results were evaluated based on the Nash-Stucliffe Efficiency Index and PBIAS, being classified as “satisfactory to very good”. Flow forecasting was also performed using the ACCESS-CM2 model considering two scenarios SSP2-4.5 (moderate) and SSP5-8.5 (pessimistic) for a future period of 10 years (2025 a 2034), and the results indicated that the type of scenario had a great influence on the magnitude of the peak discharge. The HEC-HMS software performed well and simulated the values coherently, confirming its capacity in flow forecasting.

QUANTIFICATION AND SEASONAL DISTRIBUTION OF MICROPLASTIC POLLUTION IN THE WATER COLUMN AND SEDIMENT OF THE MEIA PONTE RIVER, UPPER PARANÁ RIVER BASIN, CENTRAL BRAZIL

2025-07-07T16:37:16-03:00

Plastic waste pollution in rivers is a growing concern due to its impact on environmental quality and human livelihoods. These environments act as conduits and reservoirs of plastic pollution, interacting with the aquatic ecosystem. This study aimed to determine the presence of microplastics in water (CA) and sediment (SE) samples from the Meia Ponte River, which drains the metropolitan region of Goiânia, between November 2023 and August 2024. The results indicated the presence of microplastics in both types of samples, with greater abundance in SE, especially during the dry season and in samples collected downstream of the urban stretch. The analyses revealed significant differences among the variables assessed, reflecting specific characteristics of each sampling site throughout the study period. Furthermore, the results showed that SE is influenced by CA, suggesting the impact of anthropogenic activities within the Meia Ponte River basin, associated with rainfall and surface runoff.

AVALIAÇÃO DE DIFERENTES SISTEMAS DE SUPORTE A TOMADA DE DECISÃO PARA A GESTÃO DE RECURSOS HÍDRICOS

2025-06-03T15:05:33-03:00

Com a crescente demanda pelo uso da água e a atual escassez hídrica, as ferramentas de suporte à decisão auxiliam o gestor na tomada de decisão considerando aspectos como demanda e oferta dos recursos hídricos. Nesse contexto, este trabalho teve como objetivo realizar uma análise comparativa entre alguns sistemas de suporte à decisão (SSD), de modo a levantar elementos sobre a aplicabilidade desses sistemas no gerenciamento de recursos hídricos. A análise comparativa foi realizada considerando o SIGA e o Acquanet, dois softwares abertos, de uso gratuito, e o SSD do SIGARH, utilizado no estado do Paraná, integrado ao sistema de outorgas do Instituto Água e Terra (IAT), órgão gestor de recursos hídricos do estado. Para cada um deles foi realizado o estudo detalhado de seu funcionamento, aplicabilidade e suas informações específicas. A partir dessas determinações foram estabelecidos cenários de simulação para a mesma condição inicial. Os softwares analisados indicam na saída os valores de déficit e escassez da demanda. O SSD do Paraná também indica uma classificação quanto à disponibilidade hídrica. No cenário simulado, todos os softwares apresentaram valores de déficit hídrico, indicando uma área com alta demanda de usuários e recursos hídricos limitados, sendo necessário adotar estratégias para garantir que os recursos hídricos sejam distribuídos de maneira igualitária e sustentável. Os softwares possuem características distintas, porém todos se mostram relevantes para a gestão dos recursos hídricos, sendo assim a escolha do melhor SSD dependente do perfil do usuário tomador de decisão e das necessidades de cada análise.