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Abstract(s)
O estuário do Rio Guadiana foi escolhido pelo 6a Programa-quadro de projecto
SPICOSA como umo dos locais piloto para a pesquisa de novas ferramentas de
gestao de águas e costas. O enriquecimento excesivo da água com nutrientes e
matéria orgânica provenientes de descargas de águas residuais não tratadas e das
actividades agrícolas é o principal problema a resolver neste estuário transfronteiriço
entre Espanha e Portugal. Atraves de este trabalho, procura-se a obtenção das
preferências individuais da população local para uma melhoria da qualidade da água,
aqui definido como o valor de não-mercado atribuído à la qualidade das águas
estuarinas. A tradução de tais preferências em termos económicos facilita a
elaboração da análise custo-benefício, útiles para apoiar o processo de decisão
aplicado a gestão do ecossistema estuarino. Para este efeito foi desenvolvido o
método de avaliação contingente para uma melhoria da qualidade da água no estuário
do rio Guadiana baseado em um inquerito realizado in situ o 23 de janeiro de 2009.
A valoração incluiu tanto (1) uma questão referendo para determinar se os inquiridos
estão dispostos a contribuir ou não para melhorar a qualidade das águas estuarinas e
(2) uma questão aberta para descobrir qual é o montante máximo que os inquiridos
estão dispostos a pagar (DAP) em apoio a esta melhoria. Os valores correspondentes
a la máxima disponibilidade para pagar foram explicados usando um modelo tipo
Tobit, enquanto a pergunta referendo foi elucidada usando um modelo tipo Logit. A
máxima DAP aumentou principalmente com a renda dos inquiridos, enquanto que a
questão referendo foi essencialmente dependente do tipo de uso que os inquiridos
fazen do estuário. A média da DAP foi estimada em 42, 55 € por família por mês,
resultando em um benefício total da política ambiental de 3,812449 milhões de €. As
diferenças entre as declarações da DAP nos dois países serão analisados e discutido
o significado dos modelos resultantes.
The Guadiana river estuary was chosen as one of the pilot sites to research into new water and coastal management’s tools in the 6th Framework Programme SPICOSA project. The excess of nutrients and organic matter in water coming from untreated waste waters discharges and farm activities is one of the main problems to be solved in this transboundary estuary shared by Spain and Portugal. This work deal with the individual preferences of local people for a water quality improvement, here defined as a non-market value attributed to the estuarine water quality. The translation of such preferences in economic terms facilitates the elaboration of cost-benefit analysis that can be useful to support decision-making process applied to water and coastal management of the estuarine ecosystem. For that purpose the Contingent Valuation method for a water quality improvement in the Guadiana River estuary was carried out based on an in situ survey in 23 January 2009. The valuation exercise included both, (1) a referendum question to determine whether respondents are willing to contribute or not to improve estuarine water quality and (2) an open question to find out what is the maximum amount that respondents are willing to pay (WTP) for such improvement. The corresponding WTP values were explained using a Tobit model while the referendum question was elucidated using a Logit model. The maximum WTP was seen to rise mostly with the revenue of respondents, while the referendum question was seen to depend mainly on the use that respondents make of the estuary. Mean of WTP was estimated at 42, 55 € per family per month, resulting in a total environmental policy benefit of 3, 812449 € millions. The difference between the WTP statements in the two countries is analyzed and the significance of the resulting models is discussed.
The Guadiana river estuary was chosen as one of the pilot sites to research into new water and coastal management’s tools in the 6th Framework Programme SPICOSA project. The excess of nutrients and organic matter in water coming from untreated waste waters discharges and farm activities is one of the main problems to be solved in this transboundary estuary shared by Spain and Portugal. This work deal with the individual preferences of local people for a water quality improvement, here defined as a non-market value attributed to the estuarine water quality. The translation of such preferences in economic terms facilitates the elaboration of cost-benefit analysis that can be useful to support decision-making process applied to water and coastal management of the estuarine ecosystem. For that purpose the Contingent Valuation method for a water quality improvement in the Guadiana River estuary was carried out based on an in situ survey in 23 January 2009. The valuation exercise included both, (1) a referendum question to determine whether respondents are willing to contribute or not to improve estuarine water quality and (2) an open question to find out what is the maximum amount that respondents are willing to pay (WTP) for such improvement. The corresponding WTP values were explained using a Tobit model while the referendum question was elucidated using a Logit model. The maximum WTP was seen to rise mostly with the revenue of respondents, while the referendum question was seen to depend mainly on the use that respondents make of the estuary. Mean of WTP was estimated at 42, 55 € per family per month, resulting in a total environmental policy benefit of 3, 812449 € millions. The difference between the WTP statements in the two countries is analyzed and the significance of the resulting models is discussed.
Description
Dissertação de Mestrado, Gestão da Água e da Costa, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2010
Keywords
Qualidade da água Estuários Gestão costeira Gestão dos recursos hídricos Avaliação contigencial