ISEP – DEG – Artigos
URI permanente para esta coleção:
Navegar
Percorrer ISEP – DEG – Artigos por data de Publicação
A mostrar 1 - 10 de 13
Resultados por página
Opções de ordenação
- Hydrogeochemical, isotopical and ecotohicological approach to the Paranhos spring galleries catchworks from Porto urban area (nw Portugal)Publication . Guimarães, Laura; Afonso, Maria José; I. Chaminé, Helder; Marques, José M.; Carreira, Paula; Costa, Isilda; Teixeira, José; Guilhermino, Lúcia; Carvalho, José Martins; Fonseca, Paulo E.; Rocha. Fernando T.; Beleza, VitorinoThis multidisciplinary study presents the preliminary results of the hydrogeochemical, isotopical and ecotoxicological analyses performed to assess the nature and suitability for use of groundwater from the Paranhos’ spring galleries catchworks. These springs constituted for more than five centuries one of the main water supplies to Porto city. For the characterisation of the underground area (ca. 3km extension and a-25m of depth), constituted mainly by granitic rocks, the following tools were applied: i) subsurface geological and geotechnical mapping and; ii) hydrogeological, isotopical and ecotoxicological techniques. Surface and subsurface fieldwork surveys were first carried out to identify major tectonic accidents responsible for groundwater circulation paths and to assess lithological and structural heterogeneity. Hydrogeological fieldwork campaigns were then performed, and in situ determinations included: temperature (°C), pH and electrical conductivity (uS/cm). Several sampling sites were subsequently established, based on the surface activities located on the course of the springs, and water samples were collected for hydrogeochemical, isotopical and ecotoxicological analyses. All the water samples have been analysed for major element concentration. The isotopic techniques employed included d2H and d18O. For ecotoxicological evaluation standard acute bioassays with Daphnia magna were performed. For each sample, two 48h-LC5o bioassays were simultaneously performed: one with PH correction and the other without pH correction. In each bioassay, five concentrations of groundwater were prepared by dilution of the original sample with ASTM hard water. The hydrogeochemical analyses showed a nitrate and sulphate-enriched composition for these groundwaters, probably resulting from intense urbanisation, sewer leakage and some agricultural practices. Concerning the ecotoxicological analyses, no mortality was observed in any of the tests performed. The results obtained in this study suggest that part of Porto urban groundwater could be suitable for irrigation uses, but additional tests must be carried out to verify its compliance with existing standards of water quality. Specifically, geoenvironmental and ecotoxicological studies are required to assess potential variations in water composition and toxicity associated with seasonal changes in climate and human activities.
- A preliminary hydrogeologic conceptual model of the Manteigas-Nave de Santo Antonio-Torre sector (Serra da Estrela Natural park, central Portugal)Publication . Marques, Jorge Espinha; Marques, José M.; Carreira, Paula M.; I. Chaminé, Helder; Fonseca, Paulo E.; Samper, Javier; Pisani, B.; Alvares, D.; Vieira, Gonçalo T.; Mora, Carla; Teixeira, José; Gomes, Alberto; Carvalho, José Martins; Borges, Frederico S.; Rocha, Fernando T.; Beleza, VitorinoThis work is strongly connected with one of the most crucial water research issues at the turn of the millennium “High Mountain Areas Hydrology” (UNESCO IHP-VI Programme). Special emphasis is dedicated to high mountains and their role and impact on surface water/groundwater interaction at Serra da Estrela region - Central Portugal, in order propose a preliminary hydrogeologic conceptual model of the Manteigas - Nave de Santo Antonio - Torre sector, contributing to i) increase knowledge on recharge and discharge processes in this high mountain area and ii) assess the role of snowmelt as a source of groundwater resources, with the aid of coupled isotopic and geochemical techniques. The isotopic signatures of Caldas de Manteigas thermomineral waters combined with the i) morphostructural data and ii) isotopic composition of shallow groundwater and precipitation samples, made it possible to identify possible recharge areas, which should be located at altitude sites above 1500 m a.s.l.. The recharge altitudes are similar to those of Nave de Santo Antonio area which is directly located on the Braganca-Vilarica-Manteigas fault zone. This tectonic structure should play an important role in groundwater recharge and circulation towards the discharge zone at the Spas.
- Geodynamic evolution of the SW Europe VariscidesPublication . Ribeiro, António; Munhá, José; Dias, Rui; Mateus, António; Pereira, Eurico; Ribeiro, Luísa; Fonseca, Paulo; Araújo, Alexandre; Oliveira, Tomás; Romão, José; Chaminé, Helder I.; Coke, Carlos; Pedro, JorgeThe early evolution of SW Europe Variscides started by opening of the Rheic ocean at 500 Ma, splitting Avalonia from Armorica/Iberia. Subduction on the SE side of Rheic generated the Paleotethys back-arc basin (430–390 Ma, splitting Armorica from Iberia), with development of Porto-Tomar-Ferreira do Alentejo (PTFA) dextral transform defining the boundary between continental Armorica and Finisterra microplate to the W. Obduction of Paleotethys was followed by Armorica/Iberia collision and emplacement of NW Iberian Allochthonous Units at 390–370 Ma, whereas toward the west of PTFA, there was antithetic ophiolite obduction (Beja-Acebuches and Rheic ophiolites plus Finisterra continental slices) on top of Ossa-Morena Zone, with simultaneous development of eclogites and orogenic magmatism under a flake– double wedge tectonic regime. Continued convergence (<370 Ma) proceeded by intracontinental deformation, with progressive tightening of the Ibero-Armorican Arc through dextral transpression on the Cantabrian Indentor, from Iberia to Armorica. The proposed model is discussed at the light of the driving mechanism of ‘‘soft plate tectonics.’’
- Using engineering geosciences mapping and GIS-based tools for georesources management: lessons learned from rock quarryingPublication . Chaminé, Helder I.; Afonso, Maria José; Teixeira, José; Ramos, Luís; Fonseca, Luís; Pinheiro, Rogério; Galiza, António CarlosThe heterogeneity of the geological properties of rock masses is very important in engineering geosciences and rock engineering issues. The study of discontinuous rock masses has developed enormously. In particular, the assessment of in situ block size plays a key role in rock engineering design projects such as mining, quarrying and highway cutting operations. The application of Geographic Information Systems to engineering geosciences has become more common. In this article, the importance of an integrative comprehensive approach to rock engineering is discussed in the context of quarrying operations, i.e., from field mapping surveys to geomechanical assessment. This approach led us to a better understanding of the appropriateness of exploitation of raw material aggregates and to reduced uncertainty about sustainability of georesources in relation to their management and the environment.
- On a dialogue between hard-rock aquifer mapping and hydrogeological conceptual models: insights into groundwater explorationPublication . Chaminé, Helder I.; Carvalho, José Martins; Afonso, Maria José; Teixeira, José; Freitas, LilianaGroundwater is a dynamic and renewable resource, but in hard-rock terrains its availability is rather limited compared to other types of aquifer formations. Groundwater systems require a comprehensive understanding of geology, morphotectonics and hydrology, which are controlled by ground characteristics like weathering grade, fracturing degree, permeability, slope, drainage pattern and density, land cover, and climate. GIS-based integrative cartography provides an accurate way to improve knowledge on water circulation models and on the global functioning of aquifer systems. The groundwater conceptual model based in Earth systems has proven its value in water resource studies. This approach highlights the importance of groundwater exploration mapping as a useful tool to support hydrogeological conceptualisation of fractured hard-rock terrains, contributing to the sustainability of water resources.
- From historical hydrogeological inventory through GIS mapping to problem solving in urban groundwater systemsPublication . Chaminé, Helder I.; Afonso, Maria José; Freitas, LilianaWater resources have had a huge impact on the socioeconomic sustainability and development of urban areas. The close relationship between water and human society has been important throughout the history of civilization. The water supply for early urban settlements included mainly the use of river canals, rainwater-harvesting systems, wells, aqueducts and underground cisterns. The industrialisation period in Europe promoted an increase in population and expansion of urban areas. Furthermore, several epidemics devastated European urban areas in the period between the18th and 19th centuries. Unhygienic conditions caused by polluted water, human and animal waste and excreta were among the main causes. This study discusses the importance of historical hydrogeological inventories in a large urban area, such as Porto city (NW Portugal), to better comprehend the evolution of urban water supply systems. In that approach urban geosciences need to advance towards a smart urban geoscience concept.
- Role of hydrogeological mapping in groundwater practice: back to basicsPublication . Chaminé, Helder I.; Carvalho, José Martins; Teixeira, José; Freitas, LilianaMaps are of key importance in groundwater professional practice and hydrogeology research, mainly in field data synthesis and communication related to a number of fields: regional hydrogeology, exploration hydrogeology, groundwater engineering, hydrogeophysics, hydrogeomorphology, urban groundwater, military geology/engineering, thermal water resources, planning, management and decision making on the water resources. This paper highlights the importance and necessity of accurate ground field surveys at several scales, water resources inventory and an integrated groundwater mapping as useful tools to support hydrogeological conceptualisation. Selected sites are highlighted to demonstrate the importance of groundwater mapping for assessment of water resources. Conceptualisation of groundwater systems must be grounded on Earth-based models and mathematical modelling to outline predicting scenarios. Thus, going back to basics is important to create a reliable conceptualization on groundwater systems established on cartographic reasoning.
- From engineering geosciences mapping towards sustainable urban planningPublication . Chaminé, Helder I.; Teixeira, José; Freitas, Liliana; Pires, Ana; Silva, Rui S.; Pinho, Telma; Monteiro, Rosália; Costa, Ana Lúcia; Abreu, Tiago; Trigo, José Filinto; Afonso, Maria José; Carvalho, José MartinsMaps are of key topical importance in urban geoscience and engineering practice, mainly in field data synthesis and communication related to a number of fields, such as geomatic techniques, applied geology and geomorphology, engineering geology, soil and rock geotechnics, slope geotechnics, subsurface site geotechnical investigations, urban hydrology, hydraulics and sanitation, coastal zones management, urban geoarcheology and heritage, planning and land use. The value of preparing engineering geoscience maps and plans specificallyfor urban engineering purposes are still a challenging task, particularly to end-users and planners. Nowadays, the application of Geographic Information Systems to geosciences and engineering has become more common. This paper emphasises the importance of an accurate ground field survey and inventory at several scales, GIS mapping and databases, and integrated multidisciplinary urban studies as useful tools to support a sustainable land use planning. Some selected sites are highlighted to demonstrate the importance of urban mapping for land use planning. Thus, in this study the significance of a smart urban geoscience approach is stressed.
- Environmental Groundwater Vulnerability Assessment in Urban Water MinesPublication . Afonso, Maria José; Freitas, Liliana; Pereira, Alcides; Neves, Luís; Guimarães, Laura; Guilhermino, Lúcia; Mayer, Bernhard; Rocha, Fernando; Marques, José Manuel; Chaminé, Helder I.A multidisciplinary approach was developed to estimate urban groundwater vulnerability to contamination combining hydrogeology, hydrogeochemistry, subterranean hydrogeotechnics, groundwater ecotoxicology and isotope tracers. Paranhos and Salgueiros spring waters in Porto City were used as a case study. Historical and current vulnerability scenarios were compared using hydrogeological GIS-based modelling. Potential contamination sources were mapped around the spring galleries. Most of these were point sources and their potential contamination load was moderate. The ecotoxicological assessment indicated a low acute toxicity potential. Groundwater radionuclides appeared to be mainly controlled by geological factors and biomineralisation. Vulnerability maps suggest that most of the area has a moderate to low vulnerability to contamination. However, some surface sources such as sewage systems cause contamination and contribute to increased vulnerability. This integrated approach was demonstrated to be adequate for a better knowledge of urban hydrogeological processes and their dynamics, and highlighted the importance of a vulnerability assessment in urban areas.
- Delineating Groundwater Vulnerability and Protection Zone Mapping in Fractured Rock Masses: Focus on the DISCO IndexPublication . Meerkhan, Helen; Teixeira, José; Marques, Jorge Espinha; Afonso, Maria José; Chaminé, Helder I.Hard-rock catchments are considered to be source of valuable water resources for water supply to inhabitants and ecosystems. The present work aims to develop a groundwater vulnerability approach in the Caldas da Cavaca hydromineral system (Aguiar da Beira, Central Portugal) in order to improve the hydrogeological conceptual site model. Different types of information were overlaid, generating several thematic maps to achieve an integrated framework of key sectors in the study site. Thus, a multi-technical approach was used, encompassing field and laboratory techniques, whereby different types of data were collected from fields such as geology, hydrogeology, applied geomorphology and geophysics and hydrogeomechanics, with the fundamental aim of applying the so-called DISCO index method. All of these techniques were successfully performed and an intrinsic groundwater vulnerability to contamination assessment, based on the multicriteria methodology of GOD-S, DRASTIC-Fm, SINTACS, SI and DISCO indexes, was delineated. Geographic Information Systems (GIS) provided the basis on which to organize and integrate the databases and to produce all the thematic maps. This multi-technical approach highlights the importance of groundwater vulnerability to contamination mapping as a tool to support hydrogeological conceptualization, contributing to improving the decision-making process regarding water resources management and sustainability.