Percorrer por autor "Palha, Paulo"
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- Green roofs as contributors for water management schemes within urban areas : a pilot study in PortoPublication . Monteiro, Cristina; Calheiros, Cristina; Pimentel-Rodrigues, Carla; Palha, Paulo; Silva-Afonso, Armando; Castro, PaulaWater scarcity is an issue of worldwide concern and a holistic approach to water management is needed to overcome the potential threats that climate change brings to water availability and security in many parts of the globe. Societal and economic challenges need to be addressed when implementing technological solutions to environmental problems. The fact that green areas in the cities have been reduced and replaced by impervious buildings and paved streets has caused a number of problems, such as an increase in the amount of stormwater runoff discharged into the public drainage system. Green roof (GR) structures promote several ecosystem services and can counteract such effect and contribute to manage stormwater floods within city settlings, at the same time allowing for their storage for later reuse by collecting some of the rainwater into the growing substrate and reducing the runoff into the public drainage system (Schroll et al., 2011), and these advantages can be enhanced with the installation of a system of rainwater harvesting in the buildings. At the same time, Mediterranean countries are among those with high risk of water stress and rainwater harvesting in buildings can be a measure to promote water use efficiency. The present research study shows an example of established GRs at a pilot scale in the city of Porto (fig 1) (Monteiro et al., 2016). Different growing substrates and aromatic plants species were used to evaluate the runoff coefficients applicable to our Mediterranean climate, in order to assess the GR capacity for rainwater runoff delay. This contributes to improve the basis for the design of rainwater harvesting systems in buildings with GR in Mediterranean climate, particularly in regard to runoff coefficients and aspects of water quality and its reuse.
- Growing substrates for aromatic plant species in green roofs and water runoff quality: pilot experiments in a Mediterranean climatePublication . Monteiro, Cristina M.; Calheiros, Cristina S. C.; Palha, Paulo; Castro, Paula M. L.Green roof technology has evolved in recent years as a potential solution to promote vegetation in urban areas. Green roof studies for Mediterranean climates, where extended drought periods in summer contrast with cold and rainy periods in winter, are still scarce. The present research study assesses the use of substrates with different compositions for the growth of six aromatic plant species - Lavandula dentata, Pelargonium odoratissimum, Helichrysum italicum, Satureja montana, Thymus caespititius and T. pseudolanuginosus, during a 2-year period, and the monitoring of water runoff quality. Growing substrates encompassed expanded clay and granulated cork, in combination with organic matter and crushed eggshell. These combinations were adequate for the establishment of all aromatic plants, allowing their propagation in the extensive system located on the 5th storey. The substrate composed of 70% expanded clay and 30% organic matter was the most suitable, and crushed eggshell incorporation improved the initial plant establishment. Water runoff quality parameters - turbidity, pH, conductivity, NH4(+), NO3(-), PO4(3-) and chemical oxygen demand - showed that it could be reused for non-potable uses in buildings. The present study shows that selected aromatic plant species could be successfully used in green roofs in a Mediterranean climate.
- Potentialities of infrared thermography application to green roofs aromatic plants surface temperature evaluationPublication . Monteiro, Cristina; Calheiros, Cristina; Palha, Paulo; Freitas, Sara; Ramos, Nuno; Castro, Paula M. L.
- Potentialities of infrared thermography application to green roofs aromatic plants surface temperature evaluationPublication . Monteiro, Cristina M.; Calheiros, Cristina; Palha, Paulo; Freitas, Sara de; Ramos, Nuno M.M.; Castro, Paula M. L.Introduction: In the last decades, urban environment climate has faced some gradual changes due to the replacement of vegetation by impervious areas. As a consequence, several environmental problems have appeared in urban centres. Rooftops are a significant part of the hard surfaces in urban areas changing the heat balance and thus increasing the heat island effect. Vegetation can have a positive effect in the microclimate and macroclimate lowering urban air temperature in the buildings surroundings due to evapotranspiration and shading. Therefore, green roof technology may help to overcome this well-known problem. In the present study, two green roof platforms with different substrates have been implemented with aromatic plant species. Infrared thermography studies have been performed to assess the effect of different aromatic plants on temperature mitigation. However, several limitations of this technique must be considered, namely, emissivity and exterior conditions. These limitations can be overcome with dynamic measurements, for different periods, which will be a future development of this work. Conclusions: The use of vegetation on roofs appears as a potential alternative technology that contributes to the mitigation of the urban heat island effect. The green roof structure as building component influences the microclimate in urban areas, especially due to the vegetation contribution. This contribution was positively evaluated with infrared thermography measurements for different green roof plant species in spite of the inherent technology limitations. The present research study will contribute to the application of infrared thermography as a technique to assess the surface temperature on green roofs vegetation at a smaller scale and to the urban environment at a larger scale.
- Substrate influence on aromatic plant growth in extensive green roofs in a Mediterranean climatePublication . Monteiro, Cristina M.; Calheiros, Cristina S. C.; Martins, João P.; Costa, Francisco M.; Palha, Paulo; Freitas, Sara de; Ramos, Nuno M. M.; Castro, Paula M. L.Green roofs have been described as technical solutions to overcome urban environmental problems, such as decrease of vegetation and stormwater management. In the present study, two pilot 20 m2 extensive green roofs were implemented in an urban Mediterranean region, at a 1st storey on a warehouse building structure, in order to test the adequacy of different substrates for supporting aromatic plants (Lavandula dentata, Helichrysum italicum, Satureja montana, Thymus caespititius and Thymus pseudolanuginosus). Experimental substrates included expanded clay and granulated cork as main components, supplemented with organic matter and crushed egg shell. A commercial substrate that obeys to FLL guidelines was also tested. Plant growth was assessed and compared within each platform. All experimental substrates proved to be adequate for vegetation growth, with the combination of 70% expanded clay, 15% organic matter and 15% crushed egg shell showing the best results regarding plant establishment and growth over time. Water runoff quality parameters - turbidity, pH, conductivity, NH4+, NO3−, PO43− - met standard values required for water reuse for non-potable purposes, such as toilet flushing or irrigation. Preliminary qualitative thermographic measurements comparing surface temperature of different plant species and the substrate showed that temperature of vegetation surface was lower than substrate, reinforcing green roofs benefits of lowering air temperature in their surroundings. The present research shows that aromatic vegetation combined with clay substrates are suitable for green roofs located in countries of the Mediterranean region.