Showing papers in "Revista Brasileira de Recursos Hídricos in 1999"

A Política de Recursos Hídricos e o Princípio Usuário-Pagador (PUP)

Abstract: The administration of the water resources in Brazil received a great inpulse with the Federal Law 9433/97, and, in a complementary way, the states have been answering to this effort with the approval of its respective state laws. These laws bring to society a set of management instruments that may cause great impacts on its activities in a direct and/or indirect way. Many doubts and some anxiety have arised because the mentioned instrument includes the water use charging. At the Rio Grande do Sul state the Law 10.350/94 has already anticipated this possibility. This article aims to examine the User Pays Principle (UPP) a generalization of the Polluter Pays Principle (PPP) to the water resources management considering the actual perspective of its utilization based on the recently promulgated Brazilian Law. Initially the work describes the establishment of charges for the water usage. Then the UPP is examined in a certain depth considering two contexts: Cost-Benefit and CostEffectiveness. Finally, based on a recent study performed for a Brazilian river basin an application exercise is undertaken using a water taxation as a problem of cost sharing and using an equity crite-

Caracterização da Variabilidade Espacial de Parâmetros Hidráulicos em Solos Aluviais no Estado de Pernambuco.UCO

Abstract: The spatial variability of saturated hydraulic conductivity is analysed using both statistical and geostatistical methods. The importance of the latter has been highlighted to infer the parameter correlation structure . Data from an irrigated area in Pernambuco State was used. The parameter spatial variability model is comprised by the identified correlation structure, which is the basis to interpolate the parameter outside the measurement points, through kriging.

Novo método para estimativa da umidade do solo na condição de capacidade de campo

Abstract: A new method to estimate the field capacity is presented. For its application, it is enough to know the soil water retention curve data for each depth and to adjust the Van Genuchten’s equation to them in order to obtain the independent parameters (α, m, n, θr and θs) of the equation. By using the “THETACC” BASIC program and the parameter values obtained, field capacity can be estimated for some specified rate of internal drainage (τ). The value of τ (= 0,01.Ks) was able to estimate the field capacity for both homogeneous and heterogeneous soils.

Desenvolvimento de um Sistema de Apoio à Cobrança pelo Uso da Água: Aplicação à Bacia do Rio dos Sinos, RS

Abstract: The development of a Decision Support System for water use taxation is presented. This instrument is conceived as a cost allocation problem. Through equity criteria, the amount of payment for each water use is computed, in such a way that financial resources for river basin investments are obtained. The system was developed using a spreadsheet to make it flexible to test alternatives decisions negotiated in a River Basin Committee, for instance. It is tested in a simulation of water uses taxation in the River Sinos basin, RS. A set of 5 simulations was done, varying the amount of money to be obtained and using several alternative types of subsidies. The results showed that irrigation is the use most vulnerable to water taxation. The need to use some kind of subsidies, direct or crossed, to avoid unwilled impacts in some economic or social sectors was also emphasized. This is the case of rural population and irrigation, for instance, which are more sensitive to taxes.

Determinação da evapotranspiração potencial do brasil aplicando o modelo de thornthwaite a um sistema de informação geográfica

Abstract: Os dados de temperatura media do ar re-gistrados nas normais climatologicas (1961 – 1990) do INMET/MA foram aplicados ao modelo de Thornthwaite para estimar a evapotranspiracao potencial mensal no Brasil, associado a um Siste-ma de Informacao Geografica (SIG). Para corrigir a tendencia desse modelo em superestimar a ET

Modelagem da precipitação horária por meio do modelo de pulsos retangulares de bartlett-lewis modificado

Abstract: 19’ W, e altitude 48.2 m). Foi utilizada a serie de 16 anos de dados de precipitacao horaria observada no ajuste dos parâmetros do modelo para cada mes, assumindo a homogeneidade das caracteristicas de precipitacao dentro do mes. Com os parâmetros ajus-tados foram simuladas series de 500 anos de dados de precipitacao horaria. Observou-se que os parâme-tros do modelo refletem a variacao sazonal das caracteristicas da precipitacao, e que o modelo ajus-tado foi capaz de manter as caracteristicas estruturais da chuva observada nos diferentes niveis de agrega-cao. Nos meses de dezembro a marco foi observado maior frequencia e maior intensidade media da preci-pitacao no periodo da tarde, sendo que o modelo utilizado nao considera essa variacao diurna nas ca-racteristicas da precipitacao.

Otimização da operação de reservatório pela programação dinâmica em um processo de decisão markoviano

Abstract: Although it is a technique which is frequently used to optimize the operational policy of reservoirs, dynamic programming (PD) still has dimensionality problems. A stochastic PD model was proposed to optimize water use in a reservoir for regulation purposes, considering the inflow and irrigation demand as random variables organized in a first order Markovian process. The model was applied to Poção da Ribeira reservoir, in the state of Sergipe, and offered an optimal solution for monthly discharge. No problems of memory allocation and processing speed occurred when five levels of the state variable (stored volume), five levels of the decision variable (discharge) and five conditional probability classes were used, in a computer with medium processing capacity. Higher levels of these variables help obtain more reliable information, but they could compromise model resolvability. The results obtained by this model are the same as those found in the stochastic linear programing model in that the reservoir can operate with an approximately 5 hm/month discharge ten months a year.

Valoração monetária de bens e serviços ambientais: revisão do estado-da-arte sob a ótica da gestão das águas

Abstract: Application of techniques for monetary valuation of environmental goods and services is a promising tool for project and policy analysis for integrated water resources and environmental management. Firstly, some relationships between economics and the environmental issues are considered. The main valuation techniques are described focusing their strengths and weaknesses as well as their suitability to the water resources field using some application examples. The application of these techniques is analysed in the Brazilian context and some Brazilian examples involving water resources are presented. The concepts and techniques mentioned are considered as potentially useful to the integrated water resources and environmental management, provided that the conceptual and methodological limitations are considered, as well as the Brazilian social, economic and cultural characteristics.

Analogia de \"RollWaves\" ao Problema de Van Der Pol.

Abstract: The purpose of this article is a detailed invest igat ion of the Van Der Pol problem adaptability to explain roll-waves phenomena. In this context, a linear instability analysis for uniform flow was undertaken. Two conditions were obtained from this analysis: i) F > φ (k, σ (F,ε,θ), Re, C*, α) with F: Froude’s Number, k: wave number, σ: function of Froude, ε: steepness, θ: channel slope l; Re: Reynold’s Number, C*: Bingham’s parameter (fluid cohesion) and α the coefficient presented into the momentum equation that takes into account the different velocity profiles. ii) 1

Correlações Visando Reduzir o Número de Medições Fluvio-Sedi-Mentométricas.

Abstract: This paper presents experimental research on the correlation between the mean suspended sediment concentration of flow and those measured by point samplers and integrating samplers. During five years concentration was measured at seven verticals by integrating sampler, and by point sampler in the following positions: y = 0,0.D; y = 0,2.D; y = 0,6.D; y = 0,8.D, from the depth, and y = 3,5 cm, from the bottom. Also presented is the correlation between mean flow velocity and mean velocity calculated by integrating the velocity profile in the thalweg; between the average velocity calculated by integrating the velocity profile in the thalweg, the average velocity of flow and those measured in positions: y = 0,0; y = 0,2.D; y = 0,6.D; y = 0,8.D; from de depth, and y = 0,16 cm from the bottom. The velocities were measured during five years. Good linear relations were obtained between concentrations as well as between velocities by regression analysis of field data. Information presented in this paper was very important to reduce the number of samplings and operational costs.

Análise dos custos de um sistema elevatório de água em função do diâmetro da tubulação de recalque e modalidades de aplicação das tarifas de energia elétrica

Abstract: In this paper were analyzed the costs of an electric power water pumping system to supply center pivot irrigation systems. The independent variables were: i) pipeline diameter; ii) application modalities of electric energy tariffs with and without the special discount for irrigation done between 11 PM and 5 AM. Finally, a sensitivity analysis of the total annual cost in relation to the electric energy tariff variation was considered. The cost simulations enabled the selection of the best system configuration, contributing to the rational use of electric energy.