Research On Groundwater Quality Of Large-scale Irrigation

Jinghui Irrigation Area is a very important grain base base on Guanzhong Plain ShaanxiProvinee. Jinghui Irrigation Area product5.8%of the grain of the whole province with2.4%of the cultivated land of the whole province. In the80′s, most of the groundwater which cansupply up to1.7～2.3million m3, conform to the standard of agricultural irrigation. Inrecent years, however, due to the natural factors and human factors,the production of thegroundwater are increasing,which leads to the serious decline of groundwater level andoverweight of multiple water quality parameters.This paper studied the status of water qualityand the chemical composition of water,which can provide an important science basias forexploiting groundwater resources rationally and treating the groundwater pollution.Through the analysis of samples data of2012,we know that:the northeastern ofSanYuanxian and the southeastern of LinTong county is the most serious pollution area;Groundwater is given priority to with brackish water and hard water; don’t like Ca2+,whichthe change of concentration areas is not clearly, the concentration of Na++K+、Mg2+、HCO3-、Cl-、SO42-increase gradually from west to east; only8.82%of the monitoring wells reachedthe standard of drinking water; Since2009, except JingYang xian,the water quality ofSanYuan xian,GaoLing xian,LinTong qu and YanLiang qu has a tendency to deteriorate;groundwater chemical types mainly for SO4·HCO3·Cl-Na·Mg;the groundwater hydrodynamicconditions of western is better than the east; The formation of the chemical composition ofgroundwater is mainly affected by the leached effect and concentration effect; The correlationcoefficient that TDS with Na++K+、Cl-、SO42-is more than0.85,which is highly correlated; Inthe process of flow of groundwater, calcite, glauber’s salt and rock salt are dissolved.Through the analysis of samples data from1990to2012,we know that:the highconcentration area of HCO3-、Cl-、SO42-are closing; the high concentration area of Na++K+、Ca2+are widing; besides Ca2+of which the average concentration changes very little, theaverage concentration of Na++K+、Mg2+、HCO3-、Cl-、SO42-have tendency to expand with time.