Outflow dynamics in a French system of vertical wetlands operating with an extended feeding cycle.

The possibility of using the first stage of the French System (FS) of vertical wetlands composed of only two units in parallel requires hydraulic investigations to allow a better understanding of its operation under tropical climatic environments. This study evaluated the pattern of the outflow hydrograph along an extended cycle of operation (seven days of feeding) and the influence of the sludge deposit, rainfall occurrence and duration of pulse application on the outflow hydrograph in a modified full-scale FS in Brazil. The results indicated that, as the feeding cycle days increased, there was an increase in the time of filtration and the internal storage of the liquid volume, probably due to a reduction in the filter permeability. Greater hydraulic gradient favoured the infiltration velocity, decreased the amount of liquid stored within the system, and delayed the loss of permeability. The sludge layer contributed to a momentary liquid retention, and also allowed greater evapotranspiration, reducing the liquid volume to be treated. The sludge deposit seemed to hinder the liquid percolation, especially at the end of the cycle, modifying the hydraulic conductivity of the filter as a whole. Intense rainfall events demonstrated that precipitation could modify the flow dynamics within the system.

Estudos de externalidades na área de saúde humana decorrentes de reservatórios hidrelétricos / Human health externalities studies derived from hydropower plants reservoirs

O objetivo deste trabalho foi apresentar um método para se estimarem os valores das externalidades na área de saúde associadas à operação de reservatórios hidrelétricos. O método foi aplicado nos municípios de Uberaba e Uberlândia, Minas Gerais, parcialmente alagados pelo reservatório de Miranda. Foram analisados o número de internações hospitalares na rede do Sistema Único de Saúde e o crescimento populacional dos municípios alagados. Havendo relação de causa e efeito entre o lago e os impactos à saúde, o custo da externalidade em 2001 - quando US$ 1 equivalia a R$ 2,36 - foi estimado em R$ 25 mil, sendo a população associada a esse valor de 773.409 pessoas. A valoração econômica dos impactos mostrou que os mesmos são pouco expressivos.

The objective of this work was to present an estimation method of the values of the health externalities associated to the operation of hydro power plants reservoirs. The method was applied in the cities of Uberaba and Uberlândia, Minas Gerais, Brazil, partially flooded by Miranda reservoir. The number of hospital admittances in the Public Health System and the population growth in the flooded municipal districts were analyzed. If there is a cause-effect relation between the lake and the diseases, the costs of externalities in 2001 were estimated in R$ 25,000 when US$ 1 corresponded to R$ 2,36; the population number linked to this value was 773.409. The economical value of the health impacts showed that they do not have much significance.

Metodologia para estimação de externalidades agropecuárias decorrentes da construção de reservatórios / Methodology to estimate livestock and agricultural externalities derived from hydro power reservoirs construction

O objetivo deste trabalho é o de apresentar uma metodologia que avalia e quantifica as perdas agropecuárias que ocorrem quando da construção de reservatórios para a geração de energia elétrica. Foram estudados sete reservatórios da CEMIG situados no Estado de Minas Gerais. A produção agropecuária foi obtida de acordo com dados do IBGE relativos a 2001. As áreas municipais alagadas foram calculadas com base em dados georeferenciados fornecidos pela ANEEL. Ao final, os valores das externalidades foram comparados ao custo da energia elétrica e ao PIB municipal para a avaliação da significância dos resultados. Verificou-se que quanto maior o valor da área municipal alagada, mais relevante será a externalidade. Como exemplo, o município de Grupiara tem 40 por cento de suas terras inundadas pelo lago de Emborcação. Entre todas as localidades estudadas, esta foi aquela onde a externalidade agropecuária foi mais relevante.

The objective of this work is to present a methodology that evaluates and quantifies the agricultural and livestock losses that happen when reservoirs for the electric power generation are constructed. Seven CEMIG reservoirs, located in Minas Gerais State were studied The agricultural and livestock production were obtained in agreement on with IBGE 2001 data. The municipal areas were calculated based in georeference data supplied by ANEEL. The externalities values were compared to the electric power cost and to municipal gross domestic product to evaluate the significance of the results. It was verified that as larger is the value of the municipal flooded area, more relevant is the externality. As example, the city of Grupiara has 40 percent of their lands flooded by the lake of Emborcação. Among all the cities studied, that was the one where the agricultural and livestock externalities were more significant.