In the last decade,North Africa has witnessed significant population growth,particularly those bordering the Mediterranean Sea.This led to increased demand for groundwater,which is an essential source for various wate...In the last decade,North Africa has witnessed significant population growth,particularly those bordering the Mediterranean Sea.This led to increased demand for groundwater,which is an essential source for various water uses such as drinking water supplies and irrigation.Generally,human activities play a crucial role in the different quantitative and qualitative changes in groundwater.Now,climate changes such as a decrease in precipitation have also led to a shortage of water resources and a decline in the groundwater table.This paper presents the impact of climate changes on groundwater resources in the Ain Azel region,Setif,northeastern Algeria.The analysis of longterm spatiotemporal variability in rainfall over 63 years(1958–2021)revealed a significant decline in groundwater recharge,especially after 2013.In contrast,the Pettitt and Mann–Kendall tests show increased temperatures with breaks between 1984 and 1986.A piezometric analysis of the alluvial aquifer demonstrated a significant decline in groundwater levels in the last 20 years.Hydrochemical analysis showed that groundwater in the region is dominated by Ca–Mg–Cl water type,which indicates the presence of water salinity phenomenon.Water Quality Index(WQI)analysis showed the deterioration of groundwater in the area,which may be caused by several factors:brine intrusion from the Salt Lake(Sebkha)in the north;the dissolution of evaporites(Triassic)and/or anthropogenic sources of agricultural and industrial origin.Our findings provide an overview summarizing the state of groundwater,which will help improve groundwater resource management in the region in the coming years.展开更多
This paper deals with the results of a hydrogeochemistry study on the thermal waters of the Constantine area, Northeastern Algeria, using geochemical and statistical tools. The samples were collected in December2016 f...This paper deals with the results of a hydrogeochemistry study on the thermal waters of the Constantine area, Northeastern Algeria, using geochemical and statistical tools. The samples were collected in December2016 from twelve hot springs and were analyzed for physicochemical parameters(electric conductivity, p H,total dissolved solids, temperature, Ca, Mg, Na, K, HCO_3,Cl, SO_4, and SiO_2). The waters of the thermal springs have temperatures varying from 28 to 51 °C and electric conductivity values ranging from 853 to 5630 l S/cm. Q-mode Cluster analysis resulted in the determination of two major water types: a Ca–HCO_3–SO_4 type with a moderate salinity and a Na–K–Cl type with high salinity. The plot of the major ions versus the saturation indices suggested that the hydrogeochemistry of thermal groundwater is mainly controlled by dissolution/precipitation of carbonate minerals, dissolution of evaporite minerals(halite and gypsum), and ion exchange of Ca(and/or Mg) by Na. The Gibbs diagram shows that evaporation is another factor playing a minor role. Principal Component Analysis produced three significant factors which have 88.2% of totalvariance that illustrate the main processes controlling the chemistry of groundwaters, which are respectively: the dissolution of evaporite minerals(halite and gypsum), ion exchange, and dissolution/precipitation of carbonate minerals. The subsurface reservoir temperatures were calculated using different cation and silica geothermometers and gave temperatures ranging between 17 and 279 °C. The Na–K and Na–K-Ca geothermometers provided high temperatures(up to 279 °C), whereas, estimated geotemperatures from K/Mg geothermometers were the lowest(17–53 °C). Silica geothermometers gave the most reasonable temperature estimate of the subsurface waters overlap between 20 and 58 °C, which indicate possible mixing with cooler Mg groundwaters indicated by the Na–K–Mg plot in the immature water field and in silica and chloride mixing models. The results of stable isotope analyses(δ^(18) O and δ~2 H) suggest that the origin of thermal water recharge is precipitation, which recharged from a higher altitude(600–1200 m) and infiltrated through deep faults and fractures in carbonate formations. They circulate at an estimated depth that does not exceed 2 km and are heated by a high conductive heat flow before rising to the surface through faults that acted as hydrothermal conduits.During their ascent to the surface, they are subjected to various physical and chemical changes such as cooling by conduction and change in their chemical constituents due to the mixing with cold groundwaters.展开更多
In the northern part of Algeria,the intensive exploitation of groundwater resources and pollution has considerably affected the aquifer water quality,especially in rural areas where groundwater is the main source of w...In the northern part of Algeria,the intensive exploitation of groundwater resources and pollution has considerably affected the aquifer water quality,especially in rural areas where groundwater is the main source of water supply for most uses.This study was performed to evaluate the groundwater quality and its suitability for drinking and irrigation purposes through the hydrogeochemical study on the groundwater in Bougaa region(Northeastern Algeria).Fourteen groundwater samples were collected and analyzed for p H,T,EC,TDS,and major ions.Most samples are suitable for drinking based on the permissible limits of the Bureau of Indian standards(Indian standard specification for drinking water(IS 10500:2012),but only 35%of the samples are good enough for drinking purposes based on the water quality index of the groundwater.Assessment of groundwater samples from various parameters and methods such as"Electrical conductivity,Sodium adsorption ratio,Soluble sodium percentage,Magnesium adsorption ratio,Residual sodium carbonate,Permeability index,Kelly’s ratio,Wilcox’s diagram,and US salinity laboratory classification"showed that groundwater in the area is chemically suitable for irrigation uses.The Piper trilinear diagram suggests that the groundwater mainly belongs to the hydrochemical facies Ca–Mg–Cl and Na–Cl.The combination of ionic ratios,Gibbs plots,and saturation indices show that water–rock interaction,particularly the dissolution of carbonate,evaporation minerals,and ion exchange processes affects hydrogeochemistry of the area.Additional processes such as evaporation and anthropogenic pollution from various sources can also have major impacts on groundwater salinity.展开更多
文摘In the last decade,North Africa has witnessed significant population growth,particularly those bordering the Mediterranean Sea.This led to increased demand for groundwater,which is an essential source for various water uses such as drinking water supplies and irrigation.Generally,human activities play a crucial role in the different quantitative and qualitative changes in groundwater.Now,climate changes such as a decrease in precipitation have also led to a shortage of water resources and a decline in the groundwater table.This paper presents the impact of climate changes on groundwater resources in the Ain Azel region,Setif,northeastern Algeria.The analysis of longterm spatiotemporal variability in rainfall over 63 years(1958–2021)revealed a significant decline in groundwater recharge,especially after 2013.In contrast,the Pettitt and Mann–Kendall tests show increased temperatures with breaks between 1984 and 1986.A piezometric analysis of the alluvial aquifer demonstrated a significant decline in groundwater levels in the last 20 years.Hydrochemical analysis showed that groundwater in the region is dominated by Ca–Mg–Cl water type,which indicates the presence of water salinity phenomenon.Water Quality Index(WQI)analysis showed the deterioration of groundwater in the area,which may be caused by several factors:brine intrusion from the Salt Lake(Sebkha)in the north;the dissolution of evaporites(Triassic)and/or anthropogenic sources of agricultural and industrial origin.Our findings provide an overview summarizing the state of groundwater,which will help improve groundwater resource management in the region in the coming years.
基金supported by (Faculty of Earth Science, University of Constantine 1)
文摘This paper deals with the results of a hydrogeochemistry study on the thermal waters of the Constantine area, Northeastern Algeria, using geochemical and statistical tools. The samples were collected in December2016 from twelve hot springs and were analyzed for physicochemical parameters(electric conductivity, p H,total dissolved solids, temperature, Ca, Mg, Na, K, HCO_3,Cl, SO_4, and SiO_2). The waters of the thermal springs have temperatures varying from 28 to 51 °C and electric conductivity values ranging from 853 to 5630 l S/cm. Q-mode Cluster analysis resulted in the determination of two major water types: a Ca–HCO_3–SO_4 type with a moderate salinity and a Na–K–Cl type with high salinity. The plot of the major ions versus the saturation indices suggested that the hydrogeochemistry of thermal groundwater is mainly controlled by dissolution/precipitation of carbonate minerals, dissolution of evaporite minerals(halite and gypsum), and ion exchange of Ca(and/or Mg) by Na. The Gibbs diagram shows that evaporation is another factor playing a minor role. Principal Component Analysis produced three significant factors which have 88.2% of totalvariance that illustrate the main processes controlling the chemistry of groundwaters, which are respectively: the dissolution of evaporite minerals(halite and gypsum), ion exchange, and dissolution/precipitation of carbonate minerals. The subsurface reservoir temperatures were calculated using different cation and silica geothermometers and gave temperatures ranging between 17 and 279 °C. The Na–K and Na–K-Ca geothermometers provided high temperatures(up to 279 °C), whereas, estimated geotemperatures from K/Mg geothermometers were the lowest(17–53 °C). Silica geothermometers gave the most reasonable temperature estimate of the subsurface waters overlap between 20 and 58 °C, which indicate possible mixing with cooler Mg groundwaters indicated by the Na–K–Mg plot in the immature water field and in silica and chloride mixing models. The results of stable isotope analyses(δ^(18) O and δ~2 H) suggest that the origin of thermal water recharge is precipitation, which recharged from a higher altitude(600–1200 m) and infiltrated through deep faults and fractures in carbonate formations. They circulate at an estimated depth that does not exceed 2 km and are heated by a high conductive heat flow before rising to the surface through faults that acted as hydrothermal conduits.During their ascent to the surface, they are subjected to various physical and chemical changes such as cooling by conduction and change in their chemical constituents due to the mixing with cold groundwaters.
文摘In the northern part of Algeria,the intensive exploitation of groundwater resources and pollution has considerably affected the aquifer water quality,especially in rural areas where groundwater is the main source of water supply for most uses.This study was performed to evaluate the groundwater quality and its suitability for drinking and irrigation purposes through the hydrogeochemical study on the groundwater in Bougaa region(Northeastern Algeria).Fourteen groundwater samples were collected and analyzed for p H,T,EC,TDS,and major ions.Most samples are suitable for drinking based on the permissible limits of the Bureau of Indian standards(Indian standard specification for drinking water(IS 10500:2012),but only 35%of the samples are good enough for drinking purposes based on the water quality index of the groundwater.Assessment of groundwater samples from various parameters and methods such as"Electrical conductivity,Sodium adsorption ratio,Soluble sodium percentage,Magnesium adsorption ratio,Residual sodium carbonate,Permeability index,Kelly’s ratio,Wilcox’s diagram,and US salinity laboratory classification"showed that groundwater in the area is chemically suitable for irrigation uses.The Piper trilinear diagram suggests that the groundwater mainly belongs to the hydrochemical facies Ca–Mg–Cl and Na–Cl.The combination of ionic ratios,Gibbs plots,and saturation indices show that water–rock interaction,particularly the dissolution of carbonate,evaporation minerals,and ion exchange processes affects hydrogeochemistry of the area.Additional processes such as evaporation and anthropogenic pollution from various sources can also have major impacts on groundwater salinity.
