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21.
Venetsanou P. Anagnostopoulou C. Loukas A. Voudouris K. 《Theoretical and Applied Climatology》2020,140(3):1017-1030
Theoretical and Applied Climatology - This paper demonstrates a climate change impact study on the hydrological process of a data-scarce Greek watershed. The Soil and Water Assessment Tool (SWAT)... 相似文献
22.
Chahardouly basin is located in the western part of Iran and is characterized by semi‐arid climatic conditions and scarcity in water resources. The main aquifer systems are developed within alluvial deposits. The availability of groundwater is rather erratic owing to the occurrence of hard rock formation and a saline zone in some parts of the area. The aquifer systems of the area show signs of depletion, which have taken place in recent years due to a decline in water levels. Groundwater samples collected from shallow and deep wells were analysed to examine the quality characteristics of groundwater. The major ion chemistry of groundwater is dominated by Ca2+ and HCO3?, while higher values of total dissolved solids (TDS) in groundwater are associated with high concentrations of all major ions. An increase in salinity is recorded in the down‐gradient part of the basin. The occurrence of saline groundwater, as witnessed by the high electrical conductivity (EC), may be attributed to the long residence time of water and the dissolution of minerals, as well as evaporation of rainfall and irrigation return flow. Based on SAR values and sodium content (%Na), salinity appears to be responsible for the poor groundwater quality, rendering most of the samples not suitable for irrigation use. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
23.
N. Kazakis C. Mattas A. Pavlou O. Patrikaki K. Voudouris 《Environmental Earth Sciences》2017,76(9):349
Multivariate statistical analysis has been widely used for hydrogeochemical characterization of groundwater quality. In this study, hydrochemical data from three hydrological basins were used and two methods (factor and cluster analyses) were applied. The first area is the coastal area of Eastern Thermaikos Gulf where groundwater is influenced by seawater intrusion and geothermal fluids. The other two areas are the inland basins of Gallikos and Perdikas in which agricultural and industrial activities constitute the main anthropogenic pollution sources of groundwater. Initially, the aforementioned methods were applied for each area separately and resulted in a different number of significant factors and clusters, while the natural and anthropogenic influences were spatially determined in each area. Additionally, factor and cluster analyses were applied coupling data from all areas. Therefore, five clusters and three major factors were determined distinguishing the hydrochemical processes and impacts from anthropogenic activities in more detail. It is worth mentioning that the application of cluster analysis in the coupled groundwater samples of all studied areas resulted beneficially in the most hydrochemically complex area. Salinization dominates in the coastal area, while in Gallikos and Perdikas basins high concentrations of NO3 occur mainly due to agricultural activities and small livestock units. The numerous hydrochemical samples are identified as the main issue for the higher discretization and reliability of the second approach. Nevertheless, this study is associated with a number of limitations of multivariable statistical analysis regarding extreme concentrations of Cl and Na. This issue stimulates further research in overcoming and understanding these drawbacks. 相似文献
24.
Impacts of simultaneous action of drought and overpumping on Quaternary aquifers of Glafkos basin (Patras region, western Greece) 总被引:1,自引:1,他引:1
N. J. Lambrakis K. S. Voudouris L. N. Tiniakos G. A. Kallergis 《Environmental Geology》1997,29(3-4):209-215
The Glafkos river basin extends southeast of Patras and is the city's main groundwater reservoir. In the last few years,
a steady decline of the groundwater level has been observed in 19 wells due to overpumping and prolonged drought periods.
The present paper assesses the adverse simultaneous effects of drought and overpumping on the groundwater regime. Analysis
of the rainfall data of the last 60 years shows a decrease of precipitation during the last decade. Runoff measurements show
a decrease in the outflow of the Glafkos river. The increased water pumping and the decrease of recharge during the last decades
have resulted in depletion of the aquifers. Chemical analyses showed a constant reduction of the groundwater quality. Comparison
of piezometric maps of two periods with a 19-year interval shows a clear decline of the general piezometry as a result of
overpumping and drought.
Received: 11 January 1995 · Accepted: 21 November 1995 相似文献
25.
26.
Greece is dependent on groundwater resources for its water supply. The main aquifers are within carbonate rocks (karstic aquifers)
and coarse grained Neogene and Quaternary deposits (porous aquifers). The use of groundwater resources has become particularly
intensive in coastal areas during the last decades with the intense urbanization, tourist development and irrigated land expansion.
Sources of groundwater pollution are the seawater intrusion due to over-exploitation of coastal aquifers, the fertilizers
from agricultural activities and the disposal of untreated wastewater in torrents or in old pumping wells. In the last decades
the total abstractions from coastal aquifers exceed the natural recharge; so the aquifer systems are not used safely. Over-exploitation
causes a negative water balance, triggering seawater intrusion. Seawater intrusion phenomena are recorded in coastal aquifer
systems. Nitrate pollution is the second major source of groundwater degradation in many areas in Greece. The high levels
of nitrate are probably the result of over-fertilization and the lack of sewage systems in some urban areas. 相似文献
27.
In this paper the groundwater quality of the southern part of Korinthos region (north‐east Peloponnese) is discussed. The geology is characterized by a thick sequence of Neogene marls alternating with sandstones, overlain by superficial Quaternary deposits. The latter consist of a mixture of loose materials such as conglomerates, marly sandstones, sands and clay to silty sands. The area is crossed by a fault system parallel to the coastline, and the Quaternary sediments have formed extended Tyrrhenian marine terraces. Two aquifers have been identified in the area. The first is unconfined and occurs within the Quaternary sediments whereas the other is a deep confined aquifer occurring within the underlying Neogene marl series. Analysis of hydrochemical evolution over the past 30 years has indicated significant deterioration of quality owing to seawater intrusion and nitrate pollution. The various sources of pollution have rendered, to a large extent, shallow groundwater unsuitable not only for potable water supply but also for irrigation purposes. However, this is not the case for the deeper confined aquifer. Statistical analysis was used to explore the evolution of salinization during the years 1968 and 1998. In view of the alarming conditions caused by the documented groundwater quality deterioration, the need for integrated water resources management is stressed to maintain the socio‐economic growth of the region studied. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
28.
Zakynthos, an island of 408 km2 in the Ionian Sea, is completely dependent on its groundwater resources for fulfilling the demands of the water supplies.
The use of groundwater resources has become particularly intensive during the last decades because of the intense urbanization,
the tourist development and the irrigated land expansion that took place. The main aquifers are developed in limestones (karstic),
sandstones of neogene deposits (confined) and alluvial deposits (phreatic). This paper focuses on the assessment of their
hydrogeological characteristics and the groundwater quality. For this investigation, groundwater level measurements, drilling
data, pumping tests and chemical analyses of groundwater samples were used. The average annual consumption that is abstracted
from the aquifer systems, is 4.9 × 106 m3 year−1. The exploitable groundwater reserves were estimated to be 3.3 × 106 m3 year−1. In the last decades, the total abstractions exceed the natural recharge, due to the tourist development; therefore the aquifer
systems are not used safely. The results of chemical analyses showed a deterioration of the groundwater quality. According
to the analyses the shallow alluvial aquifer and the confined aquifer are polluted by nitrates at concentrations in excess
of 25 mg L−1. High sulphate concentrations might be related to the dissolution of gypsum. Seawater intrusion phenomena are recorded in
coastal parts of aquifer systems. The increased Cl− concentrations in karstic aquifer indicate signs of overexploitation. Strengths, weaknesses, opportunities and threats (SWOT)
analysis was applied in order to evaluate the SWOT of the groundwater resources. Moreover, some recommendations are made to
assist the rational management that aim at improving the sustainability of the groundwater resources of Zakynthos Island. 相似文献
29.
The northern coastal part of Korinthia prefecture can be characterized as an agrotourism center that has grown and urbanized rapidly. The area is formed of recent unconsolidated material consisting of sands, pebbles, breccias and fine clay to silty sand deposits. These deposits host the main aquifer system of the area, which depends on groundwater as a water resource. Groundwater is the main source for irrigation in the area. A total water volume of 29.2×106–34.3×106 m3 yr−1 was estimated to recharge the aquifer system from direct infiltration of rainfall, streambed infiltration, irrigation return, artificial recharge via flood irrigation and lateral subsurface inflows. The present annual abstraction ranges between 39.2×106 and 44.6×106 m3 yr−1. Groundwater abstraction in dry years exceeds renewable freshwater resources by more than 38%. Approximately 79% of the total abstraction is consumed for agriculture supply. Water balance in the coastal aquifer system is in disequilibrium; a deficit, which ranges from 4.9×106 to 15.4×106 m3 yr−1 exists. The safe yield of the coastal aquifer system has been estimated at 37.1×106 m3 yr−1 for normal hydrological year and 32×106 m3 yr−1 for severely dry hydrological year. The total abstraction is greater than the recharge and the safe yield of the aquifer. The aquifer system has shown signs of depletion, seawater intrusion and quality contamination. The integrated water resources management, securing water in the future, should include measures that augment groundwater budget in the coastal aquifer of the study area. 相似文献
30.
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