{"id":86,"date":"2022-12-27T14:50:19","date_gmt":"2022-12-27T14:50:19","guid":{"rendered":"https:\/\/books.gw-project.org\/large-aquifer-systems-around-the-world\/chapter\/box-2-brief-characterization-of-the-variations-in-geogenic-groundwater-mineralization-in-the-mega-aquifer-systemsas-indicated-in-consulted-documents\/"},"modified":"2022-12-27T22:34:11","modified_gmt":"2022-12-27T22:34:11","slug":"box-2-brief-characterization-of-the-variations-in-geogenic-groundwater-mineralization-in-the-mega-aquifer-systems-as-indicated-in-consulted-documents","status":"publish","type":"chapter","link":"https:\/\/books.gw-project.org\/large-aquifer-systems-around-the-world\/chapter\/box-2-brief-characterization-of-the-variations-in-geogenic-groundwater-mineralization-in-the-mega-aquifer-systems-as-indicated-in-consulted-documents\/","title":{"raw":"Box\u00a02\u00a0-\u00a0Brief Characterization of the Variations in Geogenic Groundwater Mineralization in the Mega Aquifer Systems (as indicated in consulted documents)","rendered":"Box\u00a02\u00a0–\u00a0Brief Characterization of the Variations in Geogenic Groundwater Mineralization in the Mega Aquifer Systems (as indicated in consulted documents)"},"content":{"raw":"
\r\n

Nubian Aquifer System<\/h1>\r\n

According to Bakhbakhi (2006), the mineralization level of groundwater in the Nubian Aquifer System increases from a TDS of 500\u00a0ppm in the southern part to hypersaline water in the northern part. The confined part of the Nubian Aquifer System contains approximately 150 thousand\u00a0km3<\/sup> of saline water, which is 25 percent of all groundwater in the Nubian Sandstone Aquifer System (Nubian and Post-Nubian combined). According to the OSS (Observatoire du Sahara et du Sahel, or in English, Sahara and Sahel Observatory) in 2020, groundwater is saline in a small part of the Post-Nubian aquifer, next to the Mediterranean Sea<\/p>\r\n\r\n

North-Western Sahara Aquifer System<\/h1>\r\n

Along the northern margin of the North-Western Sahara Aquifer System (NWSAS), shallow evaporites are present in a west-east running zone of chotts (i.e., shallow saline lakes, often dry during part of the year), some of which are more than 5000\u00a0km2<\/sup> in extent. They threaten to salinize shallow fresh waters, and that risk can be exacerbated by intensive groundwater abstraction (Bryant <\/a>et al., 1994; Mamou et al., 2006; OSS, 2020).<\/p>\r\n\r\n

Senegalo-Mauritanian Basin<\/h1>\r\n

In the western part of the Senegalo-Mauritanian Basin, in a 100-150\u00a0km wide belt parallel to the coast, the Maastrichtian aquifers (dipping deep in a westward direction) contain saline groundwater of NaCl facies, assumed to be of connate origin. Evaporite dissolution and mixing with seawater from Quaternary transgressions have affected water quality in the Continental Terminal and Quaternary aquifers (IAEA, 2017a). Excessive withdrawals led to high drawdowns in the water table and the risk of marine intrusions in coastal areas (OSS, 2020).<\/p>\r\n\r\n

Lake Chad Basin<\/h1>\r\n

The electrical conductivity level of groundwater in the Quaternary upper aquifer of the Lake Chad Basin is generally low (IAEA, 2017b), but is quite high in the center of the basin (IAEA, 2017). It is somewhat higher in the Lower Pliocene aquifer (IBRD, 2020). The Cretaceous Lower aquifer\u00a0\u2013\u00a0still poorly explored\u00a0\u2013\u00a0is highly mineralized (GWP, 2013).<\/p>\r\n\r\n

Sudd Basin<\/h1>\r\n

Salama (1977) reports that groundwater mineralization in the Sudd Basin gradually increases with depth. Furthermore, it varies laterally from 200 to 500\u00a0ppm in the peripheral zones to approximately 5000\u00a0ppm in the central part of the basin, where water flow is sluggish. A more recent report (RSS, 2015) mentions that groundwater with TDS between 1500 and 5000\u00a0mg\/L and sometimes more, is encountered in the north-eastern zone of the basin.<\/p>\r\n\r\n

Ogaden-Juba Basin<\/h1>\r\n

The total dissolved content of groundwater in the complex aquifer sequences of the Ogaden-Juba Basin is variable, but generally rather high to very high, especially at shallow depths. This is true for the Ogaden, Somalian and East-Kenyan shares of the basin (Pavelic et al., 2012). Kebede and Taye (2020) mention high salinity as one of the constraints to using groundwater from sedimentary aquifers in this region, but they are probably referring mainly to conditions in the shallow aquifers. Steyl and Dennis (2018) mention seawater intrusion in the drier countries and connate saline water affecting the Merti aquifer shared by Somalia and Kenya.<\/p>\r\n\r\n

Stampriet-Lower Kalahari Basin<\/h1>\r\n

In its south-western part (the Stampriet basin) groundwater mineralization generally increases towards south-western Botswana and the north-western Cape in South Africa (i.e., the Salt Block zone). TDS-values are above 1000\u00a0mg\/L in most of the Kalahari aquifer and reach values above 5000 in the south-western part of the area. Mineralization levels are generally lower in the artesian Auob and Nossob aquifers; in particular in the Auob aquifer (intercalated between the Kalahari and Nossob aquifers) with TDS values less than 1000\u00a0mg\/L in more than half of its area (GGRETA, 2016).<\/p>\r\n\r\n

Karoo Basin<\/h1>\r\n

Groundwater in most of the Karoo Basin is fresh (TDS between 450 and 1000\u00a0mg\/L). Concentrations of dissolved constituents increase from east to west accompanied by decreasing precipitation. High concentrations are limited to the westernmost and southernmost edges of the basin, with mean TDS in the north-western zone (around 10 percent of the total area) exceeding 3400\u00a0mg\/L. The water is partly of connate origin. Water quality in the sedimentary sequence is regarded as poorer than in the dolerite dykes, due to longer residence time (Woodford and Chevallier, 2002).<\/p>\r\n\r\n

Northern Great Plains Aquifer System<\/h1>\r\n

Upper and lower Palaeozoic aquifers of the Northern Great Plains Aquifer System are saline to hypersaline (up to more than 300,000\u00a0ppm). Saline water from these confined aquifers seeps upward to lower and upper Cretaceous aquifers. The former are most widespread, with limited freshwater zones and TDS mostly above, or far above, 3000\u00a0ppm (up to more than 10,000\u00a0ppm). TDS in the upper Cretaceous aquifers is mostly between 1000 and 3000\u00a0ppm (USGS, 2021; Betcher, 1995).<\/p>\r\n\r\n

Cambrian-Ordovician Aquifer System<\/h1>\r\n

Groundwater in large areas of the Cambrian-Ordovician Aquifer System is not used because of high salinity (high dissolved solids content). These areas cover half of the confined part of the aquifer system, including parts of Iowa, Missouri Illinois, Indiana and Wisconsin. Dissolved solids concentration tends to increase drastically with depth in these areas, up to 112,000\u00a0mg\/L (Wilson, 2012).<\/p>\r\n\r\n

California\u2019s Central Valley Aquifer System<\/h1>\r\n

Kang and Jackson (2016) report that groundwater salinity in California\u2019s Central Valley Aquifer System typically increases with depth. At depths less than 1000 m, TDS concentrations less than\u00a010,000\u00a0ppm are more common than those exceeding 10,000\u00a0ppm, while at greater depths the latter are more frequently found. The southern counties have a larger proportion of fresher water (<\u00a03000\u00a0ppm) at depths less than 1000m than the northern counties. A maximum dissolved solids concentration of 52,000\u00a0ppm has been observed in Fresno County in the San Joaquin Valley.<\/p>\r\n\r\n

High Plains Aquifer<\/h1>\r\n

From north to south, TDS in domestic wells of the High Plains Aquifer tends to increase from less than 250 to more than 2000\u00a0ppm. At greater depths mineralization tends to become higher, especially in zones where underlying deep geological formations contain saline water (DeSimone et al., 2014). In the southern part of the plains, upward movement of saline water from deeper aquifers occurs (Scanlon et al., 2012).<\/p>\r\n\r\n

Gulf and Atlantic Coastal Aquifer System<\/h1>\r\n

Fresh groundwater is present down to considerable depths and is underlain by salt groundwater in much of the Atlantic and Gulf Coastal Aquifer System. Depths below which chloride concentrations of 5,000\u00a0mg\/L or greater occur increase with distance from the coast. Nevertheless, below this fresh-saline interface there are also zones of fresh water and of brines (Meisler et al., 1988).<\/p>\r\n\r\n

Maranh\u00e3o Basin<\/h1>\r\n

Groundwater of calcium bicarbonate type and good quality prevails in the upper 100 to 150\u00a0m below ground surface in the Maranh\u00e3o Basin. Below that is a zone with a diversity of mixed water types, probably partly resulting from chemical reactions with clay layers. Below 1000 to 1500\u00a0m of depth, groundwater is usually saline, in some cases with mineral contents (TDS) exceeding 150,000\u00a0mg\/L (Rebou\u00e7as, 1976).<\/p>\r\n\r\n

Guarani Basin<\/h1>\r\n

Natural groundwater quality is generally good, with low mineralization in most areas of the Guarani Basin. Hydrogeo\u00adchemical and isotopic data show that formations underlying parts of the Guaran\u00ed Aquifer System (SAG) \u2013 mostly saline aquitards \u2013 contribute to observed salinity and significant trace element increases. Downdip increases in groundwater salinity are observed, with high salinities in the extreme southwest of the SAG in Argentina (Hirata and Foster, 2020).<\/p>\r\n\r\n

Arabian Aquifer System<\/h1>\r\n

Groundwater mineralization in the Paleogene (Umm-er-Radhuma and Damman formations) and Neogene aquifers of the Arabian Aquifer System increases from approximately 1000\u00a0mg\/L (at the western edge) to saline and hypersaline near the Arabian Gulf Coast. Salinity is related to upward flow of deep saline groundwater (of connate origin or salinized by dissolution of evaporites) and to evaporation at inland and coastal sabkhas (UN-ESCWA and BGR, 2013).<\/p>\r\n\r\n

Indo-Gangetic-Brahmaputra Basin<\/h1>\r\n

In the Indo-Gangetic-Brahmaputra Aquifer System, 39, 38, 12 and 11 percent of the total volume in the upper 200\u00a0m has TDS of <\u00a0500; 500-1000; 1000-2500; and >\u00a02500\u00a0mg\/L, respectively. Groundwater with TDS >\u00a01000\u00a0mg\/L underlies 28 percent of the aquifer system area. The lower two-thirds of the Indus Basin aquifer area has predominantly saline groundwater (TDS\u00a0>\u00a02500\u00a0mg\/L), partly caused by anthropogenic activities. Most of the Gangetic-Brahmaputra plains have fresh to very fresh groundwater, while brackish to saline groundwater (TDS\u00a0>\u00a01000\u00a0mg\/L) is found in the northwestern part of the Ganges basin and in the coastal zone of Bangladesh (MacDonald et al., 2016).<\/p>\r\n\r\n

West Siberian Basin<\/h1>\r\n

According to Foley and others (1994), in the West Siberian Basin, Oligocene to Quaternary deposits (only a minor fraction of the total sedimentary series) form an unconfined aquifer, whereas the Jurassic to Oligocene-age rocks contain confined aquifers and aquitards. These confined aquifers and aquitards are highly mineralized (with brines in the center of the basin), which is in line with the perception that they receive little recharge. <\/a>Modern and relict permafrost are present in a large part of the basin (as indicated in Box 1<\/a>).<\/p>\r\n\r\n

North China Plain Aquifer System<\/h1>\r\n

Below most of the North China Plain (NCP) Aquifer System\u2019s alluvial plain and coastal strip, the hydrogeological sequence includes a brackish-water aquifer of large geographical extent. It overlies confined freshwater aquifers and is locally overlain by thin lenses of fresher groundwater (Foster et al., 2004). The Quaternary series of the NCP (150 to 600\u00a0m thick) contains four super\u00adimposed aquifers. Groundwater in the first one (unconfined) and the second one (shallow confined) contain fresh water in the piedmont plain zone, but it becomes saline (TDS\u00a0>\u00a02,000\u00a0mg\/L) in the central alluvial and littoral plains. The third and the fourth aquifer (both confined) contain fresh water (TDS of 300-500\u00a0mg\/L and <\u00a01,000\u00a0mg\/L, respectively) and form the main target for exploitation (Foster et al., 2003; Su et al., 2018). The brackish-water aquifer (locally overlain by thin lenses of fresher groundwater) is present below most of the alluvial plain and coastal strip. It is of large geographical extent and originates from Quaternary marine transgressions. Modern seawater intrusion occurs near the Bohai Sea coast (Shi and Jao, 2014).<\/p>\r\n\r\n

Paris Basin<\/h1>\r\n

Fresh groundwater is observed down to 1000\u00a0m of depth of the Paris Basin (Bodelle and Margat, 1980). Groundwater in the Middle Jurassic and Triassic aquifers is saline, reaching TDS values exceeding 200,000\u00a0mg\/L in the deep center of the basin, but salinity decreases to only a few hundred\u00a0mg\/L along the edge of the aquifers (Matray and Chery, 1998). The saline Jurassic (Dogger) and Triassic (Keuper, Rh\u00e9tien) aquifers are used for the production of geothermal energy (Kloppmann et al., 2010).<\/p>\r\n\r\n

Great Artesian Basin<\/h1>\r\n

Groundwater of the main tapped Lower Cretaceous-Jurassic artesian aquifers of the Great Artesian Basin is characterized by low salinity at 500-1500\u00a0mg\/L total dissolved solids in most of the area, but it is saline in large zones in the south-western and central-southern parts of the basin (where TDS increases downgradient along groundwater flowlines). The overlying Cretaceous aquifers have higher TDS and are generally brackish. Groundwater in the deeper aquifers in the Jurassic sequence range from fresh in the northern zone of the area to brackish in most of the south-western and southeastern zones (Ransley et al., 2015; Habermehl, 2020).<\/p>\r\n

Return to<\/span> where the text links to<\/span> Box 2<\/span><\/a><\/p>\r\n\r\n<\/div>","rendered":"

\n

Nubian Aquifer System<\/h1>\n

According to Bakhbakhi (2006), the mineralization level of groundwater in the Nubian Aquifer System increases from a TDS of 500\u00a0ppm in the southern part to hypersaline water in the northern part. The confined part of the Nubian Aquifer System contains approximately 150 thousand\u00a0km3<\/sup> of saline water, which is 25 percent of all groundwater in the Nubian Sandstone Aquifer System (Nubian and Post-Nubian combined). According to the OSS (Observatoire du Sahara et du Sahel, or in English, Sahara and Sahel Observatory) in 2020, groundwater is saline in a small part of the Post-Nubian aquifer, next to the Mediterranean Sea<\/p>\n

North-Western Sahara Aquifer System<\/h1>\n

Along the northern margin of the North-Western Sahara Aquifer System (NWSAS), shallow evaporites are present in a west-east running zone of chotts (i.e., shallow saline lakes, often dry during part of the year), some of which are more than 5000\u00a0km2<\/sup> in extent. They threaten to salinize shallow fresh waters, and that risk can be exacerbated by intensive groundwater abstraction (Bryant <\/a>et al., 1994; Mamou et al., 2006; OSS, 2020).<\/p>\n

Senegalo-Mauritanian Basin<\/h1>\n

In the western part of the Senegalo-Mauritanian Basin, in a 100-150\u00a0km wide belt parallel to the coast, the Maastrichtian aquifers (dipping deep in a westward direction) contain saline groundwater of NaCl facies, assumed to be of connate origin. Evaporite dissolution and mixing with seawater from Quaternary transgressions have affected water quality in the Continental Terminal and Quaternary aquifers (IAEA, 2017a). Excessive withdrawals led to high drawdowns in the water table and the risk of marine intrusions in coastal areas (OSS, 2020).<\/p>\n

Lake Chad Basin<\/h1>\n

The electrical conductivity level of groundwater in the Quaternary upper aquifer of the Lake Chad Basin is generally low (IAEA, 2017b), but is quite high in the center of the basin (IAEA, 2017). It is somewhat higher in the Lower Pliocene aquifer (IBRD, 2020). The Cretaceous Lower aquifer\u00a0\u2013\u00a0still poorly explored\u00a0\u2013\u00a0is highly mineralized (GWP, 2013).<\/p>\n

Sudd Basin<\/h1>\n

Salama (1977) reports that groundwater mineralization in the Sudd Basin gradually increases with depth. Furthermore, it varies laterally from 200 to 500\u00a0ppm in the peripheral zones to approximately 5000\u00a0ppm in the central part of the basin, where water flow is sluggish. A more recent report (RSS, 2015) mentions that groundwater with TDS between 1500 and 5000\u00a0mg\/L and sometimes more, is encountered in the north-eastern zone of the basin.<\/p>\n

Ogaden-Juba Basin<\/h1>\n

The total dissolved content of groundwater in the complex aquifer sequences of the Ogaden-Juba Basin is variable, but generally rather high to very high, especially at shallow depths. This is true for the Ogaden, Somalian and East-Kenyan shares of the basin (Pavelic et al., 2012). Kebede and Taye (2020) mention high salinity as one of the constraints to using groundwater from sedimentary aquifers in this region, but they are probably referring mainly to conditions in the shallow aquifers. Steyl and Dennis (2018) mention seawater intrusion in the drier countries and connate saline water affecting the Merti aquifer shared by Somalia and Kenya.<\/p>\n

Stampriet-Lower Kalahari Basin<\/h1>\n

In its south-western part (the Stampriet basin) groundwater mineralization generally increases towards south-western Botswana and the north-western Cape in South Africa (i.e., the Salt Block zone). TDS-values are above 1000\u00a0mg\/L in most of the Kalahari aquifer and reach values above 5000 in the south-western part of the area. Mineralization levels are generally lower in the artesian Auob and Nossob aquifers; in particular in the Auob aquifer (intercalated between the Kalahari and Nossob aquifers) with TDS values less than 1000\u00a0mg\/L in more than half of its area (GGRETA, 2016).<\/p>\n

Karoo Basin<\/h1>\n

Groundwater in most of the Karoo Basin is fresh (TDS between 450 and 1000\u00a0mg\/L). Concentrations of dissolved constituents increase from east to west accompanied by decreasing precipitation. High concentrations are limited to the westernmost and southernmost edges of the basin, with mean TDS in the north-western zone (around 10 percent of the total area) exceeding 3400\u00a0mg\/L. The water is partly of connate origin. Water quality in the sedimentary sequence is regarded as poorer than in the dolerite dykes, due to longer residence time (Woodford and Chevallier, 2002).<\/p>\n

Northern Great Plains Aquifer System<\/h1>\n

Upper and lower Palaeozoic aquifers of the Northern Great Plains Aquifer System are saline to hypersaline (up to more than 300,000\u00a0ppm). Saline water from these confined aquifers seeps upward to lower and upper Cretaceous aquifers. The former are most widespread, with limited freshwater zones and TDS mostly above, or far above, 3000\u00a0ppm (up to more than 10,000\u00a0ppm). TDS in the upper Cretaceous aquifers is mostly between 1000 and 3000\u00a0ppm (USGS, 2021; Betcher, 1995).<\/p>\n

Cambrian-Ordovician Aquifer System<\/h1>\n

Groundwater in large areas of the Cambrian-Ordovician Aquifer System is not used because of high salinity (high dissolved solids content). These areas cover half of the confined part of the aquifer system, including parts of Iowa, Missouri Illinois, Indiana and Wisconsin. Dissolved solids concentration tends to increase drastically with depth in these areas, up to 112,000\u00a0mg\/L (Wilson, 2012).<\/p>\n

California\u2019s Central Valley Aquifer System<\/h1>\n

Kang and Jackson (2016) report that groundwater salinity in California\u2019s Central Valley Aquifer System typically increases with depth. At depths less than 1000 m, TDS concentrations less than\u00a010,000\u00a0ppm are more common than those exceeding 10,000\u00a0ppm, while at greater depths the latter are more frequently found. The southern counties have a larger proportion of fresher water (<\u00a03000\u00a0ppm) at depths less than 1000m than the northern counties. A maximum dissolved solids concentration of 52,000\u00a0ppm has been observed in Fresno County in the San Joaquin Valley.<\/p>\n

High Plains Aquifer<\/h1>\n

From north to south, TDS in domestic wells of the High Plains Aquifer tends to increase from less than 250 to more than 2000\u00a0ppm. At greater depths mineralization tends to become higher, especially in zones where underlying deep geological formations contain saline water (DeSimone et al., 2014). In the southern part of the plains, upward movement of saline water from deeper aquifers occurs (Scanlon et al., 2012).<\/p>\n

Gulf and Atlantic Coastal Aquifer System<\/h1>\n

Fresh groundwater is present down to considerable depths and is underlain by salt groundwater in much of the Atlantic and Gulf Coastal Aquifer System. Depths below which chloride concentrations of 5,000\u00a0mg\/L or greater occur increase with distance from the coast. Nevertheless, below this fresh-saline interface there are also zones of fresh water and of brines (Meisler et al., 1988).<\/p>\n

Maranh\u00e3o Basin<\/h1>\n

Groundwater of calcium bicarbonate type and good quality prevails in the upper 100 to 150\u00a0m below ground surface in the Maranh\u00e3o Basin. Below that is a zone with a diversity of mixed water types, probably partly resulting from chemical reactions with clay layers. Below 1000 to 1500\u00a0m of depth, groundwater is usually saline, in some cases with mineral contents (TDS) exceeding 150,000\u00a0mg\/L (Rebou\u00e7as, 1976).<\/p>\n

Guarani Basin<\/h1>\n

Natural groundwater quality is generally good, with low mineralization in most areas of the Guarani Basin. Hydrogeo\u00adchemical and isotopic data show that formations underlying parts of the Guaran\u00ed Aquifer System (SAG) \u2013 mostly saline aquitards \u2013 contribute to observed salinity and significant trace element increases. Downdip increases in groundwater salinity are observed, with high salinities in the extreme southwest of the SAG in Argentina (Hirata and Foster, 2020).<\/p>\n

Arabian Aquifer System<\/h1>\n

Groundwater mineralization in the Paleogene (Umm-er-Radhuma and Damman formations) and Neogene aquifers of the Arabian Aquifer System increases from approximately 1000\u00a0mg\/L (at the western edge) to saline and hypersaline near the Arabian Gulf Coast. Salinity is related to upward flow of deep saline groundwater (of connate origin or salinized by dissolution of evaporites) and to evaporation at inland and coastal sabkhas (UN-ESCWA and BGR, 2013).<\/p>\n

Indo-Gangetic-Brahmaputra Basin<\/h1>\n

In the Indo-Gangetic-Brahmaputra Aquifer System, 39, 38, 12 and 11 percent of the total volume in the upper 200\u00a0m has TDS of <\u00a0500; 500-1000; 1000-2500; and >\u00a02500\u00a0mg\/L, respectively. Groundwater with TDS >\u00a01000\u00a0mg\/L underlies 28 percent of the aquifer system area. The lower two-thirds of the Indus Basin aquifer area has predominantly saline groundwater (TDS\u00a0>\u00a02500\u00a0mg\/L), partly caused by anthropogenic activities. Most of the Gangetic-Brahmaputra plains have fresh to very fresh groundwater, while brackish to saline groundwater (TDS\u00a0>\u00a01000\u00a0mg\/L) is found in the northwestern part of the Ganges basin and in the coastal zone of Bangladesh (MacDonald et al., 2016).<\/p>\n

West Siberian Basin<\/h1>\n

According to Foley and others (1994), in the West Siberian Basin, Oligocene to Quaternary deposits (only a minor fraction of the total sedimentary series) form an unconfined aquifer, whereas the Jurassic to Oligocene-age rocks contain confined aquifers and aquitards. These confined aquifers and aquitards are highly mineralized (with brines in the center of the basin), which is in line with the perception that they receive little recharge. <\/a>Modern and relict permafrost are present in a large part of the basin (as indicated in Box 1<\/a>).<\/p>\n

North China Plain Aquifer System<\/h1>\n

Below most of the North China Plain (NCP) Aquifer System\u2019s alluvial plain and coastal strip, the hydrogeological sequence includes a brackish-water aquifer of large geographical extent. It overlies confined freshwater aquifers and is locally overlain by thin lenses of fresher groundwater (Foster et al., 2004). The Quaternary series of the NCP (150 to 600\u00a0m thick) contains four super\u00adimposed aquifers. Groundwater in the first one (unconfined) and the second one (shallow confined) contain fresh water in the piedmont plain zone, but it becomes saline (TDS\u00a0>\u00a02,000\u00a0mg\/L) in the central alluvial and littoral plains. The third and the fourth aquifer (both confined) contain fresh water (TDS of 300-500\u00a0mg\/L and <\u00a01,000\u00a0mg\/L, respectively) and form the main target for exploitation (Foster et al., 2003; Su et al., 2018). The brackish-water aquifer (locally overlain by thin lenses of fresher groundwater) is present below most of the alluvial plain and coastal strip. It is of large geographical extent and originates from Quaternary marine transgressions. Modern seawater intrusion occurs near the Bohai Sea coast (Shi and Jao, 2014).<\/p>\n

Paris Basin<\/h1>\n

Fresh groundwater is observed down to 1000\u00a0m of depth of the Paris Basin (Bodelle and Margat, 1980). Groundwater in the Middle Jurassic and Triassic aquifers is saline, reaching TDS values exceeding 200,000\u00a0mg\/L in the deep center of the basin, but salinity decreases to only a few hundred\u00a0mg\/L along the edge of the aquifers (Matray and Chery, 1998). The saline Jurassic (Dogger) and Triassic (Keuper, Rh\u00e9tien) aquifers are used for the production of geothermal energy (Kloppmann et al., 2010).<\/p>\n

Great Artesian Basin<\/h1>\n

Groundwater of the main tapped Lower Cretaceous-Jurassic artesian aquifers of the Great Artesian Basin is characterized by low salinity at 500-1500\u00a0mg\/L total dissolved solids in most of the area, but it is saline in large zones in the south-western and central-southern parts of the basin (where TDS increases downgradient along groundwater flowlines). The overlying Cretaceous aquifers have higher TDS and are generally brackish. Groundwater in the deeper aquifers in the Jurassic sequence range from fresh in the northern zone of the area to brackish in most of the south-western and southeastern zones (Ransley et al., 2015; Habermehl, 2020).<\/p>\n

Return to<\/span> where the text links to<\/span> Box 2<\/span><\/a><\/p>\n<\/div>\n","protected":false},"author":1,"menu_order":26,"template":"","meta":{"pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-86","chapter","type-chapter","status-publish","hentry"],"part":121,"_links":{"self":[{"href":"https:\/\/books.gw-project.org\/large-aquifer-systems-around-the-world\/wp-json\/pressbooks\/v2\/chapters\/86","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/books.gw-project.org\/large-aquifer-systems-around-the-world\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/books.gw-project.org\/large-aquifer-systems-around-the-world\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/books.gw-project.org\/large-aquifer-systems-around-the-world\/wp-json\/wp\/v2\/users\/1"}],"version-history":[{"count":5,"href":"https:\/\/books.gw-project.org\/large-aquifer-systems-around-the-world\/wp-json\/pressbooks\/v2\/chapters\/86\/revisions"}],"predecessor-version":[{"id":205,"href":"https:\/\/books.gw-project.org\/large-aquifer-systems-around-the-world\/wp-json\/pressbooks\/v2\/chapters\/86\/revisions\/205"}],"part":[{"href":"https:\/\/books.gw-project.org\/large-aquifer-systems-around-the-world\/wp-json\/pressbooks\/v2\/parts\/121"}],"metadata":[{"href":"https:\/\/books.gw-project.org\/large-aquifer-systems-around-the-world\/wp-json\/pressbooks\/v2\/chapters\/86\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/books.gw-project.org\/large-aquifer-systems-around-the-world\/wp-json\/wp\/v2\/media?parent=86"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/books.gw-project.org\/large-aquifer-systems-around-the-world\/wp-json\/pressbooks\/v2\/chapter-type?post=86"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/books.gw-project.org\/large-aquifer-systems-around-the-world\/wp-json\/wp\/v2\/contributor?post=86"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/books.gw-project.org\/large-aquifer-systems-around-the-world\/wp-json\/wp\/v2\/license?post=86"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}