The Chemical Characteristics And Available Analysis Of Unconfined Groundwater In The Typical Area Of North East China Plain

Hengshui is in central of North China Plain as the study area, the location is extremely important and the freshwater resource is shortage, it's potential of the development and utilization of unconfined water are great. The Hengshui city was chose as the typical area. On the base of expatiation the background of hydrogeology and the data of chemical analysis on the water sampling, the classification methods of FKLF, SL and Piper was used to analysis the chemical system of deep and shallow groundwater. The multi-year changes of salinity were contrasted, and main ion was analysis using correlative analysis and regression analysis. The relation of the different ion was decided using cluster analysis and factor analysis. Finally, discuss the formation of a genetic mechanism using the formative conditions of salt groundwater, made the use of salt water distraction, there is a very important value for guiding local agricultural irrigation.There are the conclusions:1. There are complex chemistry types of groundwater. Generally speaking, Cl- and Na + are the highest contents. In the shallow water samples, there are five types that Cl·SO₄-Mg·Na, Cl·HCO₃-Na, HCO₃·Cl·SO₄-Na·Mg·Ca, Cl·SO₄-Na·Mg and Cl·SO₄-Na·Mg·Ca. It shows the complexity of the formative environment and the sources about the shallow groundwater.2. Though the chemistry types and formation is complex, using the comparative analysis of salinity about years of the shallow underground, the desalination of shallow groundwater has a clear trend, because of the impaction of the precipitation and mining.3. The detection rate of NO₃^- in the water samples is high. And through cluster analysis and factor analysis, NO₃^- has poor relation with other ions. So it has a different source and result from the water pollution of human activities.4. Based on the rate of hydrogeochemical factors, the salinity, the chemical characteristics of salt water , the distribution and the comprehensive analysis of environmental background about the Quaternary Geology of Hebei Plain, the two ways causing of salt water was decided that were marine origination and inland drought secondary formation. Because of significantly human impact, the characteristics of the two types reflect of mainland salinity, seawater intrusion and human impact.5. Through the relative analysis of different irons in deep and shallow groundwater, the vertical hydraulic links between the two types of groundwater was confirmed. The shallow groundwater was polluted and the salinity was increased And the deep water had the deteriorating trend.6. Using the methods of sodium absorption ratio (SAR) and irrigation coefficient, the shallow groundwater samples were evaluated. And the part which was suit for the direct irrigation was found, another part should be mixed with fresh water to the irrigation. The contour map of the rate between salt and fresh water which was made form the test of samples can guide the agricultural production.7. Through the development and utilization of shallow groundwater in the history, the prospect and the factors, the shallow water of study area have great potential for the development and utilization was concluded. And the focus of utilization is the use of salt water. The rational development and use of underground water resources can increase capacity, enhance storage capacity, improve the ecological environment and reduce the threat to freshwater resources. The gradually increasing of the exploitation about groundwater transformation saline-alkali soil, and has positive significance of water and land resources utilization.The methods and prospects of development and utilization about shallow groundwater was forecast, and there is a great practical significance and broad prospects about the research of shallow water on study area.