Experimental investigation of inertial flow processes in porous media   总被引：3，自引：0，他引：3  

Konstantinos N. Moutsopoulos  Ioannis N.E. Papaspyros  Vassilios A. Tsihrintzis   《Journal of Hydrology》2009,374(3-4):242-254

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Identifying key environmental variables structuring benthic fauna for establishing a biotic typology for Greek running waters     

Nikolaos Th. Skoulikidis  Konstantinos C. Gritzalis 《Limnologica》2009,39(1):56-66

A central aspect of the Water Framework Directive 2000/60/EC addressed to Member Countries is to proceed to type-specific ecological assessment and classification by establishing typology systems. Sixty-four permanent stream sites distributed throughout mainland Greece and islands were assessed with macroinvertebrate indicators to evaluate their ecological quality. Local and catchment scale parameters were determined and recorded to obtain an integrated assessment of the main factors affecting stream integrity and macroinvertebrate communities. Twenty-three sites were classified as reference or good status in terms of biological, chemical and hydromorphological quality with the use of various metrics. Multivariate statistical techniques were performed (MDS, BIOENV, correlation analysis and PCA) to investigate the main environmental factors structuring benthic macroinvertebrate communities and to select candidate environmental variables for establishing a biotic typology for Hellenic rivers. The results revealed relatively distinct macroinvertebrate communities within defined abiotic zones of the country. Assemblages of macroinvertebrate fauna were most strongly associated to differences in geographical position, altitude, slope, catchment area, current velocity, conductivity and water temperature. In view of the lack of sufficient data at the country level on the three last variables and after considering cause-effect relationships between large scale variables and the latter, it has been demonstrated that a number of catchment scale variables could be used as robust surrogates.  相似文献   

Soil contamination by toxic metals in the cultivated region of Agia, Thessaly, Greece. Identification of sources of contamination     

K. Skordas  A. Kelepertsis 《Environmental Geology》2005,48(4-5):615-624

A soil geochemical survey was undertaken in the cultivated region of Agia in Thessaly area, Central Greece. The objectives of the study were to assess the levels of soil contamination in respect to average concentrations of toxic metals in the region, to determine the associations between the different toxic elements and their spatial distribution and to identify possible sources of contamination that can explain the spatial patterns of soil pollution in the area. One hundred seventy three soil samples were collected and analysed by ICP-AES after digestion with a mixture of HClO₄–HNO₃–H₂O. The study focused on eleven elements (Cu, Pb, Zn, Ni, Co, Mn, As, V, Cr, Fe and Mg) and all of them except Pb have mean concentrations above the average global soil composition. The elements Ni, Cr, Mn and V show concentrations that according to G.L.C guidelines the Agia soils are classified as slightly contaminated to contaminated. Factor analysis explained 84.02% of the total variance of the data through four factors. Combined with spatial interpretation of its output, the method successfully grouped the elements according to their sources and provided evidence about their natural or anthropogenic origin.  相似文献   

Hazard zonation mapping of earthquake-induced secondary effects using spatial multi-criteria analysis     

Karpouza  Maria  Chousianitis  Konstantinos  Bathrellos  George D.  Skilodimou  Hariklia D.  Kaviris  George  Antonarakou  Assimina 《Natural Hazards》2021,109(1):637-669

Natural Hazards - The present study aims to suggest an approach that allows the simultaneous hazard zonation mapping of earthquake-induced secondary effects. The modeling process of the applied...  相似文献   

Assessing soil water content spatio-temporal variability at the hillslope scale in a headwater catchment using a multi variable interpolation model based on EMI surveys (Draix,South Alps,France)     

Florian Mallet  Simon D. Carrière  Konstantinos Chalikakis  Vincent Marc 《Environmental Earth Sciences》2018,77(13):507

To improve flood prediction in headwater catchments, hydrologists need to know initial soil moisture conditions that precede rain events. In torrential hydrology, soil moisture mapping provides a valuable tool for investigating surface runoff generation processes. In these mountainous environments, soil moisture prediction is challenging because of highly heterogeneous land cover and soil properties. This survey propose a methodology to study spatial soil moisture variations in the mountainous and torrential environment of the Draix Bléone experimental site—Laval 0.86 km². This approach associates water content measurements at the plot scale with spatialized soil bulk electrical conductivity (EC_a) measurements combined in a multivariate statistical analysis based on topographical parameters. Between the summer of 2015 and winter of 2016, four geophysical surveys were conducted under various moisture conditions and along the same pathway, using the Slingram electromagnetic induction (EMI) technique (EM31 device) in horizontal dipole to identify changes in soil properties to a depth of 3 m. These results were analyzed to determine water dynamics in this mountainous catchment. Temporal variations of EC_a vary among land cover types (forest, grassland, and black marl). A significant relationship was observed between EC_a and soil water content (SWC) measured with capacitive sensors in forest and grassland. A multiple linear regression produced using the spatial interpolation code LISDQS shows a significant correlation between EC_a and landform units depicted on a high-resolution DEM. EC_a variations decrease with distance to talwegs. Riparian zones appear as potential hydrological contributing areas with patterns varying according to moisture status. This study shows that multiple linear regression analysis and EMI make it possible to fill gaps between SWC plot measurements, over wide areas that are steep and that present numerous obstacles due to vegetation cover.  相似文献   

Sustainable groundwater resources exploration and management in a complex geological setting as part of a humanitarian project (Mahafaly Plateau,Madagascar)     

Simon Damien Carrière  Konstantinos Chalikakis  Chloé Ollivier  Tom Heath  Marie Mangin  Jean Kempf  Jacques Bablon Randriatsitohaina  Marina Gillon  Théodore Razakamanana  Jean Lapègue 《Environmental Earth Sciences》2018,77(21):734

Southwestern Madagascar is a semi-arid region and a hot-spot of global change. On the Mahafaly plateau, people live with quasi-permanent water stress and groundwater, the only available resource, is difficult to exploit due to a complex hydrogeological environment. A methodology (suitable for humanitarian projects; <?40 k€) was developed in four phases to assess the sustainable exploitation of the water resource: (A) regional scale exploration, (B) village scale exploration, (C) drilling campaign, and (D) hydro-climatic monitoring. This integrated hydrogeophysical approach involves geophysical measurements (262 TEM-fast soundings, 2588 Slingram measurements, 35 electrical soundings), hydrochemical analyses (112 samples), and a piezometric survey (127 measurements). Two groundwater resources were identified, one deep (below 150 m) and one shallow (<?20 m). Hydrochemical results highlighted the vulnerability of both resources: anthropic contamination for the shallower and seawater intrusion for the deeper. Therefore, subsequent geophysical surveys supported the siting of six boreholes and three wells in the shallow aquifer. This methodological approach was successful in this complex geological setting and requires testing at other sites in and outside Madagascar. The study demonstrates that geophysical results should be used in addition to drilling campaigns and to help monitor the water resource. In fact, to prevent over-exploitation, piezometric and meteorological sensors were installed to monitor the water resource. This unique hydro-climatic observatory may help (1) non-governmental organization and local institutions prevent future water shortages and (2) scientists to understand better how global change will affect this region of the world.  相似文献   

Erratum to: Development and validation of a novel-based combination operational air quality forecasting system in Greece     

Stamatis Zoras  Vasilis Evagelopoulos  Ioannis Pytharoulis  Athanasios G. Triantafyllou  Ioannis Skordas  Georgios Kallos 《Meteorology and Atmospheric Physics》2014,125(1-2):103-103

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Evaluation of a global ensemble flood prediction system in Peru     

Konstantinos Bischiniotis  Bart van den Hurk  Ervin Zsoter  Erin Coughlan de Perez  Manolis Grillakis  Jeroen C. J. H. Aerts 《水文科学杂志》2013,58(10):1171-1189

ABSTRACT

Flood early warning systems play a more substantial role in risk mitigation than ever before. Hydrological forecasts, which are an essential part of these systems, are used to trigger action against floods around the world. This research presents an evaluation framework, where the skills of the Global Flood Awareness System (GloFAS) are assessed in Peru for the years 2009–2015. Simulated GloFAS discharges are compared against observed ones for 10 river gauges. Forecasts skills are assessed from two perspectives: (i) by calculating verification scores at every river section against simulated discharges and (ii) by comparing the flood signals against reported events. On average, river sections with higher discharges and larger upstream areas perform better. Raw forecasts provide correct flood signals for 82% of the reported floods, but exhibit low verification scores. Post-processing of raw forecasts improves most verification scores, but reduces the percentage of the correctly forecasted reported events to 65%.  相似文献   

Site selection for drinking-water pumping boreholes using a fuzzy spatial decision support system in the Korinthia prefecture,SE Greece     

Andreas K. Antonakos  Konstantinos S. Voudouris  Nikolaos I. Lambrakis 《Hydrogeology Journal》2014,22(8):1763-1776

The implementation of a geographic information system (GIS)/fuzzy spatial decision support system in the selection of sites for drinking-water pumping boreholes is described. Groundwater is the main source of domestic supply and irrigation in Korinthia prefecture, south-eastern Greece. Water demand has increased considerably over the last 30 years and is mainly met by groundwater abstracted via numerous wells and boreholes. The definition of the most “suitable” site for the drilling of new boreholes is a major issue in this area. A method of allocating suitable locations has been developed based on multicriteria analysis and fuzzy logic. Twelve parameters were finally involved in the model, prearranged into three categories: borehole yield, groundwater quality, and economic and technical constraints. GIS was used to create a classification map of the research area, based on the suitability of each point for the placement of new borehole fields. The coastal part of the study area is completely unsuitable, whereas high values of suitability are recorded in the south-western part. The study demonstrated that the method of multicriteria analysis in combination with fuzzy logic is a useful tool for selecting the best sites for new borehole drilling on a regional scale. The results could be used by local authorities and decision-makers for integrated groundwater resources management.  相似文献   

Using Network Analysis for Emergency Planning in Case of an Earthquake   总被引：1，自引：0，他引：1  

Konstantinos Tarabanis  & Ioannis Tsionis 《Transactions in GIS》1999,3(2):187-197

Populations in several countries including Greece face a continuous earthquake hazard. Planning to explore how the authorities will conduct their actions when such incidents occur is very important. People have to move to safe areas called refuge areas. GIS network analysis tools can help predict how many and which people these refuge areas can host depending on the location of their residence. A network allocation model is used.  相似文献