... corresponding with the fifthdepositionalcycle of ThaiBinhFormation.In spatial distribution, the sediments of the first and second sequences are ratherwidespreadin the plain. The thirdsequencehasa ... represent the waterbearing properties as well as the quality of the groundwater in the region. Therefore, the important aquiferswithgoodqualit ycorrespon dswith the coarse ... According to the results of chemical analysis, the groundwater in the Holocene aquifer has arNa/rCl ratio of 1.56, ahardness of 2‐9, a pH of 7.5, a TDS content of 1.2‐11.7g/l,inparticularitsironcontentreaches1.24to33.5mg/l.Fig.2.Laminatedfinesandinterclatedwithsilt of alluvialfacies of HoloceneaquiferinVP2borehole,Hanoiarea(6.9‐7.2mdepth).Courtesy of ESTNV‐2Project(EnvironmentalScienceandTechnologyinNorthernVietnam)supportedbySDCandimplementedbyCETASDandEawag.3.2.Pleistoceneaquifer(Qp) The Pleistoceneaquiferiswidelydistributedin...