27 research outputs found

    Environmental Forest Fire Danger Rating Systems and Indices around the Globe: A Review

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    The objective of the present review is to analyze and evaluate the most used and well-performing environmental forest fire danger rating systems and indices globally, aiming to the creation of an integrated forest fire danger system for Greece. The analysis emphasizes the core input parameters that have been associated with forest fire danger (i.e., weather, vegetation, topography, and hydrology) and the computational procedure of each system index as well as the categorization of the output values. Online search engines such as Scopus, Google Scholar, WorldWideScience, ScienceDirect, and ResearchGate were used in the search for relevant literature published in scientific journals, manuals, and reports. The retrieved studies were classified and reviewed. Studies were selected for analytically describing the calculation process related to forest fire danger ignition and not being strictly geographically bound. A total of 210 studies were included in the current review, describing 63 forest fire danger systems and indices. These were analyzed and evaluated based on a scoring system. Overall, the top-rated indices were the: Nesterov’s index, Sharples’ index, Keetch and Byram’s drought index, Telicyn logarithmic, and vapor pressure deficit, and the 3rd and the 4th also proved to be the most accurate for fire-prone regions. Remote sensing indices also proved to be promising in forest fire danger estimation

    Office building refurbishment based on assesment of energy and natural resource conservation

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    When the replacement of an existing building by a new one is financially restrictive or not possible for any reason, refurbishment can be the only option. The refurbishment of a non-residential building may require a specialized study, not only because of building location, use, importance and historic significance, but also because it provides the opportunity to take measures to reduce energy consumption. A refurbishment project must consider energy consumption and propose measures to improve energy use efficiency. In this paper, the case study is presented of the refurbishment of the building of the Ministry of Commerce in Greece, located in the center of Athens. The main purpose of the study is to propose refurbishment suggestions for reduction of energy consumption and provision of comfort to the occupants. The existing condition of the building in terms of energy consumption was assessed. Then, alternatives were studied including, among others, changing the windows from single to double, adding thinner curtains and external wooden shutters, ventilating naturally the building (during the spring and summer months), and adding insulation on the external walls. In energy consumption computations for existing conditions and proposed refurbishment alternatives, the computer program tsbi3 was used. Environmental impacts and energy consumption for the production of the refurbishment materials were assessed using the computer program BEAT 2000 (Building Environmental Assessment Tool). Both pieces of software have been developed by the Danish Building Research Institute (SBI). Eleven refurbishment alternatives in terms of energy consumption reduction were tested in total using the two pieces of software. A final alternative was proposed, which, according to the study and software used, would save about 28% of the currently consumed energy in the offices of the building

    Simulation of Low Impact Development (LID) Practices and Comparison with Conventional Drainage Solutions

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    The present work aims at quantifying the benefit of Low Impact Development (LID) practices in reducing peak runoff and runoff volume, and at comparing LID practices to conventional stormwater solutions. The hydrologic-hydraulic model used was the Storm Water Management Model (SWMM5.1). The LID practices modeled were: (i) Green roofs; and (ii) Permeable pavements. Each LID was tested independently and compared to two different conventional practices, i.e., sewer enlargement and detention pond design. Results showed that for small storm events LID practices are comparable to conventional measures, in reducing flooding. Overall, smaller storms should be included in the design process

    Comparative Assessment of Various Water Quality Indices (WQIs) in Polyphytos Reservoir-Aliakmon River, Greece

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    The present study attempts to examine the comparative performance of seven different WQIs, as they were computed for Polyphytos Reservoir-Aliakmon River in Greece, based on water quality monitoring data for the period between June 2004 and May 2005. The WQIs applied were: Prati’s Index of Pollution, Bhargava’s Index, Oregon WQI, Dinius’ Index, CCME WQI, NSF WQI and the Weighted Arithmetic WQI. Significant discrepancies were observed in classification results between the different methodologies. Among others, it was concluded that NSF and Bhargava indices classify the reservoir in higher quality classes, Prati’s and Dinius indices in medium, while CCME and Oregon in lower quality categories

    Water Resources and Environment

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    Comparative Assessment of the Application of Four Water Quality Indices (WQIs) in Three Ephemeral Rivers in Greece

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    In this work, the possibility of using four water quality indices (WQIs) to evaluate the quality status of small rivers in the Mediterranean region (Northern Greece) was investigated. The WQIs selected were the NSF WQI, Oregon WQI, CCME WQI and Prati’s Index of Pollution and were applied to three rivers, namely Laspias, Kosynthos and Lissos, located in the prefectures of Xanthi and Rhodope, Northern Greece. The individual indices were calculated based on the values of 11 physicochemical parameters derived from field measurements and chemical laboratory analyses of water samples at two monitoring stations in each river. The in situ measurements and samplings were executed at a frequency of approximately 10 days and lasted 20, 12 and 10 months for rivers Laspias, Kosynthos and Lissos, respectively. The comparative results from the four indices in the three rivers showed that for rivers Kosynthos and Lissos, which had comparable values of physicochemical parameters, Prati’s and CCME indices classified these water bodies into the highest quality classes, the NSF WQI into a slightly lower class and the Oregon WQI into the lowest classes of quality ranking. Regarding Laspias River, whose physicochemical parameter values indicated inferior water quality than the other two rivers, the Oregon index ranked this water body in the lowest quality class, while the other indices in slightly higher classes. In conclusion, regarding the water quality of ephemeral streams in the Mediterranean, it seems that the Oregon index is stricter followed by the NSF, and then, Prati’s and CCME WQIs

    A fuzzy inference system for wind-wave modeling

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    International audienceForecasting of sea-state characteristics, with warning time of a few hours, appears a necessity in Operational Oceanography. linking sophisticated marine monitoring systems with forecasting modeling tools. In this paper, instead of using conventional numerical models, a Takagi-Sugeno-rule-based Fuzzy Inference System (FIS) was developed aiming at forecasting wave parameters based on the wind speed and direction, and the lagged-wave characteristics. Initial and final antecedent fuzzy membership functions were identified using the subtractive clustering method. The model was applied on the wind and wave dataset recorded in years 2000-2006 by an oceanographic buoy deployed in the Aegean Sea. The model showed perfect fit for the training period (2000-2005; 12,274 data points), and expanded its hindcasting ability during 2006 (1044 data points), as the verification part of the series. Model results, for a lead time of 3 h, showed good agreement between the predicted and the observed significant wave height (RMSE=0.216) and zero-up-crossing period (RMSE=0.315). According to other model performance criteria, the fuzzy model slightly underpredicted both wave characteristics (the linear regression slope was 0.911 for wave height and 0.788 for wave period), and reduced its forecasting ability at higher prediction intervals (+6 to + 12 h). Overall, model results illustrated that the developed FIS could serve as a valuable tool for the operational prediction of wave characteristics in Northern Aegean Sea, through the utilization of the POSEIDON network

    Potential of Two SAR-Based Flood Mapping Approaches in Supporting an Integrated 1D/2D HEC-RAS Model

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    This study investigates the potential of Sentinel-1 data in assisting flood modeling procedures. Two different synthetic aperture radar (SAR) processing methodologies, one simplified based on single-flood image thresholding and one automatic based on SAR statistical temporal analysis, were exploited to delineate the flooding caused by a storm event that took place in Spercheios River, Central Greece. The storm event was simulated by coupling a HEC-HMS hydrologic model and an integrated 1D/2D HEC-RAS hydraulic model. Both SAR methodologies were compared to each other and also used as a reference to test the sensitivity of the hydraulic model in the variation of upstream discharge and roughness coefficient. Model sensitivity was investigated with respect to the change in the derived inundation extent and three additional metrics: the Critical Success Index (CSI), the Hit Rate (HR), and the False Alarm Ratio (FAR). The model response was found to be affected in the following order: by the upstream inflow, and by the variation of the roughness coefficient in the main channel and in the land use “cultivated crops”. The discrepancies observed between model- and SAR-derived inundation products are associated with the uncertainty accompanying the SAR processing and the utilized satellite data itself, the underlying topography, and the structural uncertainty inherent in the modeling procedure. Regarding the SAR methodologies tested, the second one (FLOMPY approach) proved to be more suitable, yielding a more coherent and realistic flooded area. According to the applied metrics and considering as reference the FLOMPY result, model performance ranged between 22–27.5% (CSI), 36.9–60.4% (HR), and 62.1–68.2% (FAR)

    An Index-Based Method to Assess the Resilience of Urban Areas to Coastal Flooding: The Case of Attica, Greece

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    The aim of this study is to assess the resilience of coastal urban areas and their exposure to sea-level rise and coastal flooding, using the proposed Coastal Resilience Index (CResI). The CResI is an innovative combination of diverse characteristics. It includes 19 parameters and is implemented using GIS techniques. The parameters included in the CResI are classified into six category factors (geomorphology, flooding, wave exposition, land use, socioeconomic, and infrastructure/functional). The Analytic Hierarchy Process is used to assign weights and rank the parameters. The framework is tested in the southwest waterfront of the Athens Metropolitan Area in Greece. The study identified that around 25% of the coastal area could be at risk of coastal flooding in the upcoming years, including areas in both the metropolitan and suburban environments. As a result, the need for adaptation measures cannot be overlooked
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