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- Classification of landforms in Southern Portugal (Ria Formosa Basin)Publication . Granja-Martins, Fernando M.; Fernandez, Helena; MGP Isidoro, Jorge; Jordan, Antonio; Zavala, LorenaA Geographic Information Systems-based tool is used for macro-landform classification following the Hammond procedure, based upon a Digital Terrain Model (DTM) created from ordinary Kriging. Gentle slopes, surface curvature, highlands and lowlands areas are derived from the DTM. Combining this information allows the classification of terrain units (landforms). The procedure is applied to the Ria Formosa basin (Southern Portugal), with five different terrain types classified (plains, tablelands, plains with hills, open hills and hills).
- Soil erosion, Serra de Grandola (Portugal)Publication . Fernandez, Helena; Granja-Martins, Fernando M.; MGP Isidoro, Jorge; Zavala, Lorena; Jordan, AntonioSoil erosion has long been the subject of attention for environmental management researchers because it implies the loss of a key natural resource for sustaining life. Several methodologies for soil erosion assessment have been developed; many of these are supported by Geographic Information Systems. This study aims to classify the susceptibility of rainfall-induced erosion at the Serra de Grandola (Portugal), based on the Priority Actions Programme/Regional Activity Centre guidelines for mapping soil erosion on the Mediterranean coast. Results show a low-to-moderate susceptibility to rainfall-induced erosion in the lowlands, becoming moderate to high in the highlands of the Serra de Grandola.
- The role of Spartina maritima and Sarcocornia fruticosa on trace metals retention in Ria Formosa, PortugalPublication . Moreira, Manuela M.; Duarte, Duarte; MGP Isidoro, Jorge; Chícharo, LuísOver the last years, phytoremediation has become an increasingly recognized pathway for contaminant removal from water and shallow soils. Assessing the phytoremediation potential of wetlands is complex due to variable conditions of hydrology, soil/sediment types, plant species diversity, growing season and water chemistry. Physico-chemical properties of wetlands provide many positive attributes for remediating contaminants. Saltmarsh plants can sequestrate and inherently tolerate high metal concentrations found in saltmarsh sediments.
- Impacts of distinct spatial arrangements of impervious surfaces on runoff and sediment fluxes from laboratory experimentsPublication . Ferreira, C. S. S.; Moruzzi, R.; Isidoro, Jorge M. G. P.; Tudor, M.; Vargas, M.; Ferreira, A. J. D.; de Lima, J. L. M. P.Urbanization affects runoff processes and sediment transport, but the magnitude of the impacts remains poorly understood. Different spatial patterns of pervious and impervious surfaces influence flow and sediment connectivity between hillslopes and stream networks. Following years of research on the peri-urbanizing Ribeira dos Covoes catchment in Portugal, this study uses laboratory rainfall simulation experiments to better assess the impact of soil and pavement patterns on runoff (amount, runoff start and stop times) and sediment transport. Based on urban cores observed in the study catchment, the investigation focused on seven spatial patterns: bare soil (S), 100% pavement (P), and 60% pavement under continuous - C - surface placed upslope (CU) and downslope (CD), and dispersed - D - over the surface with regular (DR), irregular (DI) and linear (DL) distribution. A 1.00 m x 1.00 m flume, 0.05 m deep with a 9 degrees slope, facilitated the experiments. The study used sandy-loam soil (1500 kg m(-3)) with concrete slabs representing pavement. Each experiment comprised a series of four rainfall simulations, each lasting 20 min (50 mm h(-1)), separated by 30-min intervals, to assess the impact of different initial soil moisture conditions. Results indicate that both spatial pattern and soil moisture drive runoff. Under dry conditions, CD provides runoff that is 7 times faster and about 4% higher than that for CU. Already wet conditions, however, produced 12% more runoff on CU than on CD. The greater runoff arose from faster soil saturation, driven by soil moisture increasing more quickly during the rainfall, as well as upstream runoff from paved surfaces, though runoff took longer to reach the outlet. The dispersed pavement pattern only affected runoff amount, with DL producing the highest coefficients (40-71%) and DI the lowest (25-55%), since longer flow paths increase the opportunities for water infiltration. Additionally, CU yielded 40% more sediment transport than CD, but the three dispersed patterns did not show a significant impact (p > 0.05). The results suggest that appropriate planning can reduce flood hazard and land degradation in urban areas, in particular by using dispersed patterns of sealed surfaces to enhance water infiltration and retention. (C) 2019 Elsevier Ltd. All rights reserved.
- Assessment of loose and adhered urban street sediments and trace metals: a study in the city of Po double dagger os de Caldas, BrazilPublication . Silveira, Alexandre; Pereira Jr. , José A.; Poleto, Cristiano; Lima, João L. M. P. de; Gonçalves, Flávio A.; Alvarenga, Livia A.; MGP Isidoro, JorgeThis study aims to quantify and characterise sediments accumulated in the street gutters in an urban area of Po double dagger os de Caldas, Brazil. The main research questions are: What type of urban areas, e.g. those under construction, produce most sediments and what are the main characteristics of such sediments? What differences, e.g. granulometry, can be found in loose and adhered sediments? What trace metals can be found in the sediments?Fieldwork was carried out in a residential area of Po double dagger os de Caldas, Brazil. Ten samplings were conducted between May and August 2013 to collect sediments from road gutters. The collected sediments were then divided into 'loose' and 'adhered', depending on whether they were collected in a first, gentle, sweeping with soft bristled brush or in a subsequent sweeping with a stiff bristled brush. Granulometric curves were drawn for both types of sediments. Fine sediment analyses (aecurrency sign63 mu m) were performed on samples from the last five samplings. Two techniques were used to look for trace elements: energy dispersive X-ray fluorescence (EDXRF) and inductively coupled plasma-atomic emission spectrometry (ICP-AES).Larger amounts of sediments were collected after lower intensity rainfall events. Higher intensity events seemed to wash the sediments away. A correlation was found between areas under construction and sediment mass production. A characteristic range of granulometries (medium sand), found in our study is in accordance with studies by other authors. An important presence of heavy metals (Cr, Cd, Pb, Zn, Ni and Cu) was detected and characterised. As and Sn were also detected even though they are not often mentioned in the literature on urban soil pollutants.Areas under construction were found to produce more sediments than other areas. The trace metals found in highest concentrations were Pb and As. The heavy metal concentration decreases after wet periods, showing that they are carried by runoff. It is expected that this study may serve as an input for establishing diffuse pollution control and mitigation strategies for the accumulation of pollutants in the urban environment.
- Infiltration of Portuguese cobblestone pavements - An exploratory assessment using a double-ring infiltrometerPublication . Rocheta, Vera Lúcia; MGP Isidoro, Jorge; de Lima, Joao L. M. P.The present study aims to evaluate small-scale infiltration losses of Portuguese cobblestone pavements. This type of pavement consists of rectangular hand-cut natural stones, mainly limestone, with different sizes and it is the most usual type of pavement for sidewalks and squares in Portuguese villages and cities. Portuguese cobblestone pavement can also be seen in several urban environments worldwide. A double-ring infiltrometer under constant and falling head was used for the field research work. Portuguese cobblestone pavements with small and coarse blocks were studied. The latter yield lower infiltration rates when compared to the former. The results show that, despite the block size, Portuguese cobblestone pavement contribute to reduce runoff, when compared with other impervious urban pavements.
- Simulation of the transport of suspended particles and dissolved pollutants by runoff on impervious surfaces: a contribution to urban sanitationPublication . Felice, Jessica Giacchetto; Silveira, Alexandre; MGP Isidoro, Jorge; Gonçalves, Flávio Aparecido; Silva, António Marciano daOne of the impacts of urbanization on the environment is the changes in the rainfall-runoff process, causing changes in water resources quality. The objective of this project was to simulate the transport of suspended particles and pollutants dissolved on runoff, an impermeable surface at laboratory scale. The experimental model consisted on a simulator for the application of artificial rainfall on an impermeable surface with 8,40 m(2), in which sodium chloride and fine sand were distributed in four defined regions, simulating sources of diffuse pollution. The results showed differences between peak transport times of dissolved and suspended pollutants, depending on their position. The first-flush effect was observed for the dissolved pollutants independently of the source position, whereas for the pollutants transported in suspension the same effect was only found when the source was closer to the outlet of the impervious surface.
- Delimitação de áreas inundáveis por acção fluvial: aplicação ao Rio Séqua/Gilão na área urbana de TaviraPublication . MGP Isidoro, Jorge; Rocheta, Vera Lúcia da Silva; Lança, RuiA Universidade do Algarve realizou em 2008 um estudo para o Município de Tavira relativo à delimitação das áreas inundáveis causadas por extravasamento do rio que atravessa a cidade, Rio Séqua/Gilão, devido a precipitações intensas associadas a períodos de retorno de 10 e de 100 anos. O estudo em causa dividiu-se basicamente em três etapas: a realização de um estudo hidrológico da bacia hidrográfica do Rio Séqua/Gilão (221km2) com vista a determinação de caudais máximos de cheia, a realização de um estudo hidrodinâmico, no qual se efectuou a modelação numérica do troço de rio com aproximadamente 9.50km, considerando o efeito das diversas estruturas hidráulicas existentes no troço e do efeito de maré, e finalmente a identificação dos níveis atingidos pelo Rio para os caudais associados a períodos de retorno de 10 e 100 anos. Foram também analisados os resultados obtidos e identificadas soluções para minimizar o efeito das cheias na cidade de Tavira. Particular atenção foi dada à aferição do modelo utilizado, através da comparação entre os níveis de cheia atingidos na cheia de 3 de Dezembro de 1989 (através de marcas de cheia, fotografias e vídeos) e os níveis de cheia modelados. Este exercício permitiu verificar que o modelo numérico apresenta resultados muito satisfatórios nas simulações efectuadas. Foi também realizada uma simulação tendo em conta potenciais efeitos das alterações climáticas no que concerne à subida do nível médio do mar. Pretende-se apresentar uma síntese das etapas que constituíram o estudo, dando particular incidência ao trabalho de aferição existente, bem como à elaboração dos mapas de delimitação de áreas inundáveis.
- Modelling the effects of tsunami-induced forces on building facadesPublication . MGP Isidoro, Jorge; Estêvão, João Manuel CarvalhoTsunami waves cause severe structural and nonstructural damages in the shallow water and inundation areas. The intense development that coastal areas have experienced in the last decades, with a rapid growth in population and economy, has increased their exposure to tsunami waves. Recent research on tsunami modelling has been mainly centred in the hydrodynamic issues (e.g., propagation). However, the major losses, human lives and economic, occur at the inland areas, and so further knowledge on what happens in these areas is needed. Main goal of this research is the assessment of inland buildings resilience to tsunami-induced flooding.
- Enhancing the spatial rainfall uniformity of pressurized nozzle simulatorsPublication . Silveira, Alexandre; MGP Isidoro, Jorge; Deus, Fábio P. de; Reis, Simone Siqueira dos; Silva, António Marciano da; Gonçalves, Flávio A.; Bretanha Junker Menezes, Paulo Henrique; Tiezzi, Rafael de O.Purpose - Rainfall simulators are used on experimental hydrology, in areas such as, e.g., urban drainage and soil erosion, with important timesaving when compared to real scale hydrological monitoring. The purpose of this paper is to contribute to increase the quality of rainfall simulation, namely, for its use with scaled physical models. Design/methodology/approach - Two pressurized rainfall simulators are considered. M1 uses three HH-W 1/4 FullJet nozzles under an operating pressure of 166.76 kPa and was tested over a 4.00 m length by 2.00 m width V-shaped surface. M2 was prepared to produce artificial rainfall over an area of 10.00m length by 10.00m width. The spatial distribution of rainfall produced from a single nozzle was characterized in order to theoretically find the best positioning for nozzles to cover the full 100m(2) area with the best possible rainfall uniformity. Findings - Experiments with M1 led to an average rainfall intensity of 76.77-82.25 mm h(-1) with a 24.88 per cent variation coefficient and a Christiansen Uniformity Coefficient (CUC) of 78.86 per cent. The best result with M2 was an average rainfall intensity of 75.12-76.83 mm h(-1) with a 21.23 per cent variation coefficient and a CUC of 83.05 per cent. Practical implications - This study contributes to increase the quality of artificial rainfall produced by pressurized rainfall simulators. Originality/value - M2 is the largest rainfall simulator known by the authors worldwide. Its use on rainfall-runoff studies (e.g. urban areas, erosion, pollutant transport) will allow for a better understanding of complex surface hydrology processes.