Publications

The characterization of the river boundary condition infinite difference numerical models based on MODFLOW requires thequantification of a set of parameters, some of them usually difficult todefine. A methodology is presented based on the digital elevation model(DEM) and the river network, to characterize two of these parameters:the stage of the river and the length of the river in each model cell. Suggestionsare presented for the other parameters such as the riverbed bottomelevation and the width of the river to be calculated as a function ofthe river stage, and the riverbed thickness and hydraulic conductivity.The part of the methodology depending on the DEM is explained anddemonstrated using a GIS environment with reference to the GIS toolsneeded to produce the main steps. This methodology produces more representativevalues of the river stage parameter if at least 9 DEM cells permodel cell are used. This methodology allows a first approximation, ata regional scale, for the characterization of the river boundary conditionin numerical modelling.

A set of tests on failure by overtopping of earth dams was performed under hydraulic and geotechnical controlled conditions in a medium-scale facility located at the Portuguese National Laboratory for Civil Engineering. The flow over the breaching dam is three-dimensional and exhibits several length scales. Instrumentation must be able to capture this complexity and scale amplitude and must be non-intrusive. This work presents a summary of the instrumentation layout as well as its main components and measuring methods that were used and/or developed to address these issues. The emphasis is placed on post-processing analysis of digital imagery, for which there is detailed exposition of the adopted methods and an evaluation of its suitability for its intended purpose.

In assessing the impact of climate change on infrastructure, it is essential to consider the interactions between the atmosphere, vegetation and the near-surface soil. This paper presents an overview of these processes, focusing on recent advances from the literature and those made by members of COST Action TU1202

The purpose of this study was to analyze the quality of atmospheric deposition, soil, vadose zone water, and plant species in several Urban Allotment Gardens (UAG) in the city of Lisbon, and to correlate its nature and characteristics with their location within the city pressures and with the farming practices, comparing results with similar studies elsewhere. Twenty one metals or metalloids (Ag, Al, As, B, Ba, Be, Cd, Co, Cr, Cu, Fe, Li, Mn, Mo, Ni, Pb, Sb, Se, Ta, V, Zn) and 16 PAHs (acenaphthene, acenaphthylene, anthracene, fluorene, phenanthrene, naphthalene, benzo[a]anthracene, benzo[a]pyrene, benzo[b] f luoranthene, benzo[k] f luoranthene, benzo[g,h,i]perylene, chrysene, dibenzo[a,h]anthracene, fluoranthene, indeno[1,2,3-c,d]pyrene), pyrene) were analyzed in the atmospheric deposition, and some of these elements/compounds were further analyzed in soils, water, and vegetables. Results show a wide range of concentrations in the city resulting from different soil types and contamination sources. Indexes based on ratios of selected PAHs suggest pyrogenic origins for the PAHs. Metals and metalloids have both anthropogenic and petrogenic origins, the latter mainly for soils with vulcanic origin. Despite the fact that concentrations in soils and waters have exceeded the recommended values in some areas, the lettuce and cabbage rarely presented contamination, with the measured metal values generally under legislated limits, where this exist.

As alterações climáticas causam impactos no ciclo hidrológico e nas disponibilidades hídricas, criandodesafios adicionais à gestão integrada e sustentada dos recursos hídricos, nas suas componentes de qualidade,quantidade e suporte dos ecossistemas. As águas subterrâneas sofrem impactos directos das alterações climáticas (viaalterações da recarga), ou indirectos (ex.: alterações na recarga vinda dos rios), os quais se conjugam com os devidos àsevoluções demográficas, sociais, de uso e ocupação do solo e adaptação no sector da agricultura devido a alteraçõesdos ciclos de vida das culturas e pragas, pragas emergentes ou adopção de novas culturas, com consequente alteraçãode extracções de águas subterrâneas. Os estudos de alterações climáticas normalmente abarcam um horizonte de50 a 100 anos, o que dificulta as opções dos decisores, que costumam basear as suas políticas em projecções decurto prazo. O projecto BINGO tenta ultrapassar esta lacuna, fornecendo informação sobre impactos das alteraçõesclimáticas no ciclo hidrológico, incluindo os de eventos extremos, para um período de curto-médio prazo (ano 2024).A análise dos impactos das alterações climáticas sobre as águas subterrâneas recorre a um modelo 3D (FEFLOW) dosaquíferos Aluviões do Tejo, Tejo-Margem Direita e Tejo-Sado/Margem Esquerda, com recargas calculadas com modelode balanço hídrico sequencial diário a nível do solo (BALSEQ_MOD) a partir dos resultados de 10 realizações climáticasdo modelo climático regional MiKlip. Os resultados do MiKlip sugerem cenários de recarga superior e inferior à actual;o ensemble das 10 realizações indica recarga similar à actual. As alterações da recarga sobre a piezometria do aquíferosão moderadas, com subidas de 2 a 5 m no cenário de recarga máxima, e descidas de 2 a 10 m no de recarga mínima,e praticamente sem alteração no cenário ensemble das 10 realizações. Analisou-se também o impacto das secascom cenários de duração destas de 3 e 5 anos, considerando as condições do ano muito seco de 2005. Em média,os níveis descem 1 a 2 m no cenário de 3 anos e 2 a 3 m no cenário de 5 anos. Considerando que para o curto prazo,os modelos não mostram mudanças significativas face à actualidade, conclui-se que para acautelar o futuro a longoprazo é necessária uma mudança de paradigma dos decisores, que deverão passar a basear as suas políticas nãoapenas em previsões de curto prazo, mas sobretudo nas de longo prazo, começando a estabelecer políticas agora,que minorem as consequências das alterações climáticas em 2050 e 2100. Ou seja, agir agora para obter resultadosdaqui a 3 gerações.

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