The present study aims to understand the hydrochemical evolution of groundwater in the Ghaggar River Basin,representing a zone of excessive abstraction of groundwater in the northwestern Indo-Gangetic Basin.The study ...The present study aims to understand the hydrochemical evolution of groundwater in the Ghaggar River Basin,representing a zone of excessive abstraction of groundwater in the northwestern Indo-Gangetic Basin.The study comprises a regional scale and high-resolution sampling of groundwater during preand post-monsoon seasons of 2013 and their analyses for major ions,δ^(18)O,δ^(2)H,and 3 H.Variation in hydrochemical and isotopic data is found both in spatial and vertical scales.The significant vertical variation of TDS,NO_(3)and K^(+)allowed the classification of the aquifer system into two major groups:shallow(depth<80 m bgl)and deep(depth>80 m bgl).The depthwise variations ofδ^(18)O andδ^(2)H support this categorization of the aquifers.The Ca-HCO_(3)and Ca-Mg-Na-HCO_(3)water facies with higher values of 3 H in the proximal part of the basin characterize recharge areas under humid conditions.The dominance of Mg-Na-HCO_(3)and Na-HCO_(3)facies in shallow and deep aquifers in central part of the basin,illustrate the intermediate to advanced stages of hydrochemical evolution in the system.Dominance of brackish Ca-Mg-Cl-SO_(4)and Na-Cl-SO_(4)water types in the discharge areas is due to the prevailing geological conditions and anthropogenic activities.Geochemical modelling supports the reverse cation exchange and mixing during lateral and vertical flows,weathering of silicate minerals,dissolution of crustal salts,and evaporative enrichment are the natural processes governing the evolution of groundwater chemistry along the flowpaths.The developed process-based conceptual model will aid in the formulation of a suitable plan for groundwater resource management in the region.展开更多
In Algeria, the steppe areas of southern Sebdou between Tlemcen, El-Aricha and Mecheria are the scene of an adverse and continuous ecological imbalance often caused by the strong support of human pressure in these eco...In Algeria, the steppe areas of southern Sebdou between Tlemcen, El-Aricha and Mecheria are the scene of an adverse and continuous ecological imbalance often caused by the strong support of human pressure in these ecosystems. In arid and semi-arid regions, salinity remains a constraint for the development of plants. This study focuses on the realization of floristic surveys, where attention was paid to areas occupied by the dominant perennial species (Tamarix gallicaL.). A correspondence analysis by Minitab 15 software has allowed us to individualize the groups of species attracted by some parameters (edaphic, nitrates, humidity), and ecological gradients appear to affect the distribution of these taxa. The study of plant diversity shows the dominance of biological type of therophytes (41%) and morphological type of the Chenopodiaceaes with (25%). For geographical types, the strict Mediterranean and circum-Mediterranean element predominates.展开更多
基金supported by the Ministry of Earth Sciences,Government of India(Letter no:MoES/NERC/16/02/10 PC-II)the UK Natural Environment Research Council(grants NE/I022434/1 and NE/I022604/1)the Changing Water Cycle-South Asia program.One of the authors,Dr.Kossitse Venyo Akpataku was supported by Indian Government through DST under the RTF-DCS program(DCS/2018/000009)。
文摘The present study aims to understand the hydrochemical evolution of groundwater in the Ghaggar River Basin,representing a zone of excessive abstraction of groundwater in the northwestern Indo-Gangetic Basin.The study comprises a regional scale and high-resolution sampling of groundwater during preand post-monsoon seasons of 2013 and their analyses for major ions,δ^(18)O,δ^(2)H,and 3 H.Variation in hydrochemical and isotopic data is found both in spatial and vertical scales.The significant vertical variation of TDS,NO_(3)and K^(+)allowed the classification of the aquifer system into two major groups:shallow(depth<80 m bgl)and deep(depth>80 m bgl).The depthwise variations ofδ^(18)O andδ^(2)H support this categorization of the aquifers.The Ca-HCO_(3)and Ca-Mg-Na-HCO_(3)water facies with higher values of 3 H in the proximal part of the basin characterize recharge areas under humid conditions.The dominance of Mg-Na-HCO_(3)and Na-HCO_(3)facies in shallow and deep aquifers in central part of the basin,illustrate the intermediate to advanced stages of hydrochemical evolution in the system.Dominance of brackish Ca-Mg-Cl-SO_(4)and Na-Cl-SO_(4)water types in the discharge areas is due to the prevailing geological conditions and anthropogenic activities.Geochemical modelling supports the reverse cation exchange and mixing during lateral and vertical flows,weathering of silicate minerals,dissolution of crustal salts,and evaporative enrichment are the natural processes governing the evolution of groundwater chemistry along the flowpaths.The developed process-based conceptual model will aid in the formulation of a suitable plan for groundwater resource management in the region.
文摘In Algeria, the steppe areas of southern Sebdou between Tlemcen, El-Aricha and Mecheria are the scene of an adverse and continuous ecological imbalance often caused by the strong support of human pressure in these ecosystems. In arid and semi-arid regions, salinity remains a constraint for the development of plants. This study focuses on the realization of floristic surveys, where attention was paid to areas occupied by the dominant perennial species (Tamarix gallicaL.). A correspondence analysis by Minitab 15 software has allowed us to individualize the groups of species attracted by some parameters (edaphic, nitrates, humidity), and ecological gradients appear to affect the distribution of these taxa. The study of plant diversity shows the dominance of biological type of therophytes (41%) and morphological type of the Chenopodiaceaes with (25%). For geographical types, the strict Mediterranean and circum-Mediterranean element predominates.
