Nilo Nascimento

GR3J: a daily watershed model with three free parameters

This paper describes a new empirical watershed model, the prime feature of which is its parsimony. It involves only three free parameters, a characteristic unparalleled by continuous process models able to work on a wide array of catchments. In spite of its crude simplicity, it achieved, on average, worthwhile results on a set of 140 French catchments and overwhelmingly outperformed a linear model involving 16 parameters. It performed roughly as well as a conceptual model with five free parameters, derived from the well-known TOPMODEL.

Ciência, tecnologia e inovação na interface entre as áreas de recursos hídricos e saneamento

The paper presents an evaluation of emerging subjects in research, development and innovation in interface domains of environmental sanitation and water resources. The evaluation focus on the identification of research subjects with a high potential for innovation, in general terms, as well as those subjects more oriented to the solution of typical problems of the Brazilian context in the areas of environmental sanitation and water resources, for what fundamental knowledge as well as technological development are still required.

The assessment of damage caused by floods in the Brazilian context

The present paper describes theoretical aspects and the main results on the development of a methodology for the global evaluation of direct damage caused by floods. This methodology is based on the use of standard flood damage curves versus depth of inundation on dwelling, commerce and service sectors. The research was developed based on field surveys in the city of Itajubá, located in the valley of the Sapucaí River, in Minas Gerais state in the southeast region of Brazil. In January 2000, this city suffered severe floods where more of 70% of the urban area was affected; with depths of inundation higher than 3 m in certain areas. The empirical data were obtained through questionnaires applied in the ravaged area in 2002. The questionnaires allowed the characterization of the dwellings and their content, as well as the different categories on commercial and service activities. The generic curves obtained from the data in the survey were used at the same site to evaluate the amount of potential flood damage in relation to different hydrologic risks.

Pesquisa e desenvolvimento na área de saneamento no Brasil: necessidades e tendências

The paper deals with a set of dimensions about research and development on environmental sanitation, based on the national reality. The historic background, the research sense and aim, and the investigation object and method are discussed. The themes of human resources, scientific communication, technology transfer, funding and evaluation are introduced, emphasizing the need of deeper approach. A protocol regarding classification and selection of RD evaluating the social basis that support researches; discussing research objects and conceptual basis; discussing methodological frameworks; prospecting research themes, through appropriated protocol and methodology. Finally, the development of a directive plane for environmental sanitation researches, providing the basis and supporting future policies on the area, is proposed.

A method for evaluating the evolution of clogging: application to the Pampulha Campus infiltration system (Brazil)

In order to evaluate the hydraulic performance of stormwater infiltration trenches, a study was undertaken to assess clogging and its distribution between the bottom and the sides. The method used was based on the calibration of the hydraulic resistance event by event according to Bouwers model and applied to a demonstration trench in Belo-Horizonte monitored in the framework of the European Project Switch. The calibration was performed by minimizing the distance between measured and modeled infiltration flow rates and by using continuous measurements of rainfall, inflow, water temperature and depth in the trench. The study showed that the methodology and particularly Bouwers model was able to produce satisfactory results. It revealed a significant clogging evolution within a year, with global resistance increasing by a factor of 9. A significant difference between the bottom and the sides was observed; the bottom being more rapidly prone to clogging. Sudden fluctuations of the hydraulic resistance of the bottom were found that could be explained by very high concentrations of total suspended solids from inflows (about 2,000 mg/L). Clogging of the sides evolves over the time but with a very low rate.

Modelagem da Lagoa da Pampulha: uma ferramenta para avaliar o impacto da bacia hidrográfica na dinâmica do fitoplâncton

In urban areas the increasing imperviousness is responsible for rising runoff volume and speed, leading to a greater capacity to load nutrients and pollutants into reservoirs. In order to study the impacts of catchment changes on the phytoplankton dynamics in urban lakes, a modelling approach in which a hydrological model is connected to an ecological lake model is proposed for Lake Pampulha (Brazil). In this paper we present the methodology used to link both models. Lake Pampulha and its catchment area were intensively monitored between October 2011 and June 2013 in order to provide data for the calibration and validation of both models. The results of the hydrologic model showed good agreement with the in situ measurements, and the Nash coefficient ranged from 0.70 to 0.88. The lake ecological model have successfully represented the cyanobacteria dynamics (normalized mean average error: 0.25-0.42, Pearson coefficient: 0.82-0.89, p<0.0001). Monitoring and modelling showed that cyanobacteria blooms are quite disturbed by water column mixing caused by rain events. The mathematical tool developed here can be used to assess different scenarios of climate changes or catchment area changes and can be very helpful for the management of urban water resources.

Desempenho dos diferentes modelos institucionais de prestação dos serviços públicos de abastecimento de água: uma avaliação comparativa no conjunto dos municípios brasileiros

This paper presents a comparative assessment of the different institutional public models for water supply provision in Brazil. In an encompassing way, the study compares services of almost all Brazilian municipalities, by a nonparametric analysis of variance. For this assessment, services were grouped according to the following classification: managed by the municipality; managed by a municipal autarchy; private companies; and regional models. The base year of the study was 2008, and secondary data from the National Survey of Basic Sanitation were used. A set of performance indicators, related to operational and management aspects of services, was created. The results indicate significant differences between the evaluated models.

Avaliação de danos às edificações causados por inundações e obtenção dos custos de recuperação

O presente artigo descreve uma metodologia de desenvolvimento de curvas de danos de inundacao (FDC) na Regiao do Barreiro, no Municipio de Belo Horizonte, Minas Gerais. Foi realizado um estudo de caso a partir da de dados de danos causados a edificacoes atingidas pelas enchentes de 31 de dezembro de 2008 e 22 de janeiro de 2009 nessa regiao. Embora o tema venha sendo bastante pesquisado em âmbito internacional, nao existem ainda no Brasil estudos de avaliacao do efeito da inundacao sobre as construcoes e da extensao dos danos provocados pela acao da agua. Para o desenvolvimento do trabalho, foram realizadas vistorias a 62 edificacoes e identificadas as manifestacoes patologicas provocadas pelas inundacoes. Isso possibilitou o levantamento dos servicos necessarios para recuperacao das patologias observadas e a elaboracao de orcamentos para a obtencao dos custos de sua recuperacao. Os custos finais para recuperacao das 62 casas foram obtidos considerando-se a profundidade da agua de inundacao, a tipologia de projeto adotada e os custos indiretos e margem de lucro. As curvas obtidas indicam que, para o padrao construtivo normal, o aumento da profundidade de inundacao nao tem impacto significativo nos danos causados as edificacoes e que, para os padroes construtivos baixo e proletario, observa-se uma tendencia de aumento dos custos de recuperacao dos danos na medida em que se aumenta a profundidade da inundacao.

Urban water management and planning: urban sanitation policies and an emerging institutional structure

Brazilian urban politics for the last two decades have been marked by the emergence of organised sectors of civil society who progressively reclaimed their roles as subjects. Both society and state were substantially transformed in such process, and urban and environmental policies, sanitation included, based on citizens’ participation are an important and visible outcome. Participatory budgeting, national and municipal committees, municipal conferences, master plans at different geographical scales are now widespread among progressive governments. They define priorities for public resource allocation according to demands usually associated to the incomplete character of Brazilian urbanisation (where several items of material reproduction, such as housing, services and infrastructure, are missing), bringing together conflicting interests of different social agents. Departing from such approach to urbanisation, the empowering idea of citizen’s participation, and the changing context of urban policy formulation at the national level.

Impact of Urbanization (Trends) on Hydrological Behaviour of Belo Horizonte Watersheds (Brazil)

The paper presents an analysis of runoff behaviour of four, small urban catchments between the city of Belo Horizonte and Contagem in Brazil, linked to their land-use. Two year of on- line measurements of hydrological and basic water quality data, combined with spatial analysis, made it possible to compare urban catchment with different land use and urbanization and support the generally admitted hypothesis that more dense urbanization generate faster and bigger discharges, accompanied by stronger solid fluxes. These findings contribute to better understanding of the urbanization trends of Pampulha watershed and to predict measures of mitigation if actual trends go on.