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- Integrative Groundwater Studies in a Small-Scale Urban Area: Case Study from the Municipality of Penafiel (NW Portugal)Publication . Freitas, Liliana; Chaminé, Helder I.; Afonso, Maria José; Meerkhan, Helen; Abreu, Tiago; Trigo, José Filinto; Pereira, Alcides J. S. C.The occurrence of groundwater in urban hard rock areas is mostly controlled by secondary permeability caused by the fracturing degree and weathering grade. Vulnerability GIS-mapping, monitoring, and infiltration/recharge of water resources, and the delineation of the environmental protective background are key issues in evaluating, planning, managing, and decision-making for urban water systems. A small-scale urban area in Penafiel City was used as a case study. Historical and current scenarios were compared using hydrogeological GIS-based modelling. Water sources and potential contamination sources were mapped around the study area. Groundwater is mainly acidic, with a low mineralization and a Cl-Na to Cl-SO4-Na or Cl-Ca to Cl-SO4-Ca hydrogeochemical facies. Considering potential contamination sources, the moderate and the moderate-high classes dominate the area. The combined approach of the vulnerability indexes suggests that most of the area has a low to moderate vulnerability to contamination. The Infiltration Potential Index in urban areas (IPI-urban) indicates the prevalence of a low to moderate infiltration. Groundwater recharge evaluation indicates values < 2.3 mm/year and <60 mm/year for summer and winter scenarios, respectively. Finally, the investigation addresses insights for decision-makers for the appropriate planning and sustainable management of groundwater resources in small-scale urban areas.
- 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.
- Site appraisal in fractured rock media: coupling engineering geological mapping and geotechnical modellingPublication . Chaminé, Helder I.; Afonso, Maria José; Trigo, José Filinto; Freitas, Liliana; Ramos, Luís; Carvalho, José MartinsGeotechnical surveys are based on collecting data from fieldwork and are a key element of rock-mass quality assessment in rock engineering. The lessons learned in several engineering projects underline the value of the accuracy of the basic geological and geotechnical data information related to the rock masses description and evaluation. An evaluation based on engineering geosciences, hydraulic and geotechnical features of rock masses involves combining parameters to derive quantitative geomechanical classifications for engineering design. In the present work, two selected sites are highlighted to demonstrate the importance of GIS mapping and models. Mapping and quantifying the on-site measurements’ information content and building a geo-database is vital for decision-making processes and risk assessment on sustainable engineering design with nature and hazards.
- Groundwater Favourable Infiltration Zones on Granitic Areas (Central Portugal)Publication . Carvalho, José Martins; Afonso, Maria José; Teixeira, José; Freitas, Liliana; Lopes, Ana Rita; Jesus, Rosário; Batista, Sofia; Carvalho, Rosário; Chaminé, Helder I.The Infiltration Potential Index (IPI) was used at Castelo Novo (Fundão, Central Portugal) to delineate favourable infiltration zones. The Infiltration Potential Index is a valuable tool to include in integrated water resources management in crystalline fractured rocks. An integrated approach combining hydrogeomorphology and GIS was developed applying multiple layers of information (tectonic lineaments, hydrogeological units, slope, drainage, land use, and precipitation). Different ranks were assigned to thematic layers and different weights were given to classes according to their contribution for groundwater using the Analytical Hierarchical Process (AHP) methodology. Almost 80% of the area is covered by slightly to moderately weathered (W1–2–W3) granite, having slopes of 5–15° and 15–25°, tectonic lineaments densities of 6–12 km/km2 and 12–18 km/km2 and drainage densities of 6–9 km/km2 and >9 km/km2. Scrub and/or herbaceous vegetation associations and bare rocks dominate. A moderate to high Infiltration Potential Index (IPI) is dominant in the area.
- 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.
- Urban Groundwater Processes and Anthropogenic Interactions (Porto Region, NW Portugal)Publication . Afonso, Maria José; Freitas, Liliana; Marques, José Manuel; Carreira, Paula M.; Pereira, Alcides J.S.C.; Rocha, Fernando; Chaminé, Helder I.Groundwater in fissured rocks is one of the most important reserves of available fresh water, and urbanization applies an extremely complex pressure which puts this natural resource at risk. Two-thirds of Portugal is composed of fissured aquifers. In this context, the Porto urban region is the second biggest metropolitan area in mainland Portugal. In this study, a multidisciplinary approach was developed, using hydrogeological GIS-based mapping and modeling, combining hydrogeochemical, isotopic, and hydrodynamical data. In addition, an urban infiltration potential index (IPI-Urban) was outlined with the combination of several thematic layers. Hydrogeochemical signatures are mainly Cl-Na to Cl-SO4-Na, being dependent on the geographic proximity of this region to the ocean, and on anthropogenic and agricultural contamination processes, namely fertilizers, sewage, as well as animal and human wastes. Isotopic signatures characterize a meteoric origin for groundwater, with shallow flow paths and short residence times. Pumping tests revealed a semi- to confined system, with low long-term well capacities (<1 L/s), low transmissivities (<4 m2/day), and low storage coefficients (<10−2). The IPI-Urban index showed a low groundwater infiltration potential, which was enhanced by urban hydraulic and sanitation features. This study assessed the major hydrogeological processes and their dynamics, therefore, contributing to a better knowledge of sustainable urban groundwater systems in fractured media
- Forecasting and Mass Transport Modelling of Nitrates in the Esposende–Vila Do Conde Nitrate Vulnerable Zone (Portugal)Publication . Zeferino, Joel; Carvalho, Maria Rosário; Ferreira, Tânia; Silva, Maria Catarina; Afonso, Maria José; Freitas, Liliana; Lopes, Ana Rita; Jesus, Rosário; Batista, Sofia; Chaminé, Helder I.; Carvalho, José MartinsEsposende–Vila do Conde, a nitrate-vulnerable zone, in the littoral north of Portugal, is contaminated by nitrates of an agricultural origin. Measures have been implemented to reduce that contamination. The effectiveness of the measures was evaluated, predicting the time required for the groundwater body reach the quality standard, i.e., less than 50 mg/L for dissolved nitrates. Two methodologies were used, groundwater flow and nitrates transport modelling, and predictive analysis of time series. The transient simulation of nitrate transport shows that the minimization measures imposed in the NVZ are being effective. However, the persistence of concentrations above 50 mg/L in some areas is notorious even in the next 24 years. The forecasting points out to a recovery period of ten years if current agricultural practices are maintained. The prediction of NO3 concentration based on forecasting methodology may not be applicable in the long run because it is a punctual analysis, not taking into consideration the contaminant dispersion dependent on the aquifer characteristics.
- 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.
- Assessment of sustainability of groundwater in urban areas (Porto, NW Portugal): a GIS mapping approach to evaluate vulnerability, infiltration and rechargePublication . Freitas, Liliana; Afonso, Maria José; Pereira, Alcides J. S. C.; Delerue-Matos, Cristina; Chaminé, Helder I.The urban water cycle concept demonstrates the connectivity and interdependence of urban water resources and human activities, and the need for integrated sustainable management studies and approaches. The role of climate, geology, geo-morphology, land-use/cover, hydrogeochemistry, hydraulics, human activities among other features is significant in urban areas. In addition, land-use development has a stronger influence on terrestrial hydrology than climate variability. The need for provision of safe water, sanitation and drainage systems is key elements to consider for the groundwater resources in complex urban environments. In recent years, a new focus has emerged, addressing issues on integrated GIS mapping stud-ies on urban water supply systems, particularly in historical cities. To illustrate that approach the Porto urban area (NW Portugal) was selected. This work presents a comprehensive study to demonstrate the key importance of urban groundwater studies, as well as the evaluation of the Urban Infiltration Potential Index and the potential groundwater yields that might be available for non-potable uses, such as irrigation of parks and lawns, street cleaning and firefighting. This strategy is useful for the planning and management of urban groundwater abstraction in an equitable and sustainable manner.
- Geotechnical Hazards in Rocky Slopes (Northern Portugal): Focused on MethodologyPublication . Trigo, José Filinto; Pacheco, Carlos; Fernandes, João; Ferraz, Pedro; Sousa, Jorge; Machado, Rui; Duarte, Sara; Mendes, Ana; Freitas, Liliana; Teixeira, José; Ramos, Luís; Afonso, Maria José; Chaminé, Helder I.Interdisciplinary studies of rocky slopes stability have been performed on Northern Portugal, that allowed to establish a design methodology. This approach carries together the use of more traditional techniques, with the application of more recent technologies, such as unmanned aerial vehicles. This work presents a set of procedures that have been applied successfully in several case studies, describing the different stages, with an emphasis on the production of a ground three-dimensional model. This model is generated from photographs obtained with successive drone flights, with overlapping. It is the support for the development of subsequent stages, especially for the characterisation of the trajectories of rockfalls and modelling, the development of susceptibility mapping and of rock slope hazard. In this context, the Natural Slope Quality Index (N-SQI ), an adaptation of the Slope Quality Index (SQI), orientated to natural slopes, is presented. The Block Gravity Number (BGN), created in order to hierarchise rock blocks, selecting them for modelling, is also proposed.