Yvonilde Dantas Pinto Medeiros

An Objective Multi-Criteria Evaluation of Water Management Scenarios

Advanced computer models are commonly used to simulate reservoir systems performance. If the number of possible management scenarios is large, it can be extremely difficult to follow related systems operation and get a valuable picture on its spatial and temporal behavior. The decision maker or analyst can be overburdened by quantity and complexity of information generated by model, particularly if system operation is repeatedly simulated for multiyear periods. Related problem is how to select the scenario with most desired long-term consequences. Possible approach is to use selected parts of models output and re-interpret system behavior by means of certain performance indicators, create appropriate decision matrix and perform multi-criteria analysis to rank decision alternatives (scenarios). The paper proposes a methodology that includes: (1) multiyear simulations of system operation; (2) computing spatially and temporally distributed systemperformance indices such as supply reliability, resiliency and vulnerability; (3) unbiased entropy-based weighting the importance ofperformance indices; and (4) final ranking of scenarios by means of multi-criteria analysis. The number of scenarios and number of performance indices is not restricted, and to account for possibly large sets of scenarios, an ideal-point-distance multi-criteria method TOPSIS is suggested. Proposed methodology appeared to be confident and robust in proof-of-concept application in Brazil.

Avaliação e identificação de parâmetros importantes para a qualidade de corpos d'água no semiárido baiano. Estudo de caso: bacia hidrográfica do rio Salitre

Objective of this work was identifying superficial water quality parameters, significant to semi-arid hydrographic basins, minimizing costs of water monitoring. The Salitre river basin, an important sub-basin of the Sao Francisco river, was used as a case study. STD, Cl-, DO, BOD, pH, NO3-, PO43-, Al, Cu, Fe, Mn, Ni and Pb were considered the most significant parameters, with concentration levels found in some stretches of the basin not compliant with the current legislation. Some of the Salitre river basin sediments may represent a risk to the quality of the water body in relation to levels of nickel and zinc.

Cost-benefit analysis of reservoir operation scenarios considering environmental flows for the lower stretch of the São Francisco River (Brazil)

A alocacao ambiental da agua consiste em considerar o meio ambiente como licito usuario da agua. A importância em determinar as necessidades hidricas da agua para protecao do ecossistema, e reconhecida mundialmente, entretanto as implementacoes praticas de vazoes ambientais sao restritas, necessitando da avaliacao dos impactos dessa implementacao nos demais usuarios da agua. Nesse contexto, o artigo objetiva avaliar o impacto economico no setor eletrico considerando as vazoes ambientais como restricao de escoamento a jusante dos reservatorios. O estudo de caso e o baixo curso do rio Sao Francisco, uma regiao que presenta uma degradacao social e ambiental acentuada com extrema relevância para o sistema energetico do Brasil. A metodologia adotada compreendeu a construcao de cenarios de operacao de reservatorios, modelagem matematica do sistema hidrico e analise custo-beneficio para o setor energetico. A simulacao aponta a possiveis conflitos entre os usos nao consuntivos. Avaliando a analise custo-beneficio para periodos normais e secos, os primeiros resultam em perdas financeiras totais para o setor eletrico, enquanto os segundos em ganhos totais, permitindo acordos entre a geracao de energia e a implementacao de vazoes ambientais no baixo curso do rio Sao Francisco.

Inorganic and organic contaminants in drinking water stored in polyethylene cisterns

This work evaluated the presence of contaminants in stored rainwater in 36 polyethylene tanks installed in two rural communities of the semiarid of Bahia, Brazil. Carbonyl compounds were analyzed by High Performance Liquid Chromatography (HPLC-UV), BTEX (Benzene, Toluene, Ethylbenzene and Xylenes) by gas chromatoghaphy (GC-FID), and trace elements by inductively coupled plasma optical emission spectrometry (ICP-OES). Seven carbonyl compounds were quantified including acrolein (<3-115 µg L-1), which is considered a potent mutagenic agent, above the potability limit in 75% of the cases. Trace elements such as copper, zinc, barium, aluminum and lead, more frequently found, were also quantified, and lead (<0,56-99 µg L-1) was above the tolerable limit for drinking water of 10 μg L-1 in 73% of the cases. The results show that the stored water in polyethylene cisterns in the Brazilian semiarid region does not present satisfactory conditions for human consumption.

Water permit integration in the Paraguaçu River Watershed (Bahia)

In Brazil, water regulatory agencies adopt two different methodologies of equating water balance for the purposes of water permits: one that considers the uses for surface water withdrawal and waste water discharge in an integrated way, and one that analyses these two uses as demands that do not relate with each other. In the state of Bahia, this analysis disregards the integration of quantitative and qualitative uses. Furthermore, at the moment, there are not internal procedures that enable the integration of the water permit with other water resources management instruments. In this context, the aim of this work consists of analysing the advantages and limitations of the implementation of the equating methodology that integrates the quali-quantitative analysis of the water balance for purposes of water permit, compared with current procedures in the state of Bahia. For this analysis, a diagnosis of use of the Paraguaçu River Watershed (BHRP) was developed through the Water Balance Control System (SCBH), simulating the two methodologies and comparing potential water use index. The results reinforce that the methodology of equating the quali-quantitative water balance does not represent an advance for water resources management when the other instruments, present in the State Water Resources Policy, are not integrated with the water permit.