Study On Hydrochemical Character Of Karst Water And Its Indication In Jinan Spring

Jinan is a famous city for the springs, just as the proverb describes"every household has springs". With the development of economy and society, the Karst water production is increasing, which induced to series of environment problems as water level decline, water pollution, springs dried out and so on. The hydrochemical fields essentially changed. The article studied hydrochemical characters of the past 50 years on the time and space scale and its indication, posed the intrinsical regularity and hydrochemical field formation of eastern suburbs-city-western suburbs and supply-runoff-drainage. The research was significant to Jinan springs and its ecologic environment protection, rational exploitation and utilization groundwater resource. The results and innovation were summarized as following:1. Hydrogeological statistical methods were used to research the conventional hydrochemistry characteristics of 50's, 80's, 90's and after 2000 and three typical locations of eastern industrial suburb, near the spring groups, and the western suburbs. The results indicated that at first period of recent 50 years each components increased slowly then increased sharply and at last the constitent increased slowly increased, and found out the main contribution factors to make groundwater components changed. The hydrochemical components of three typical areas increased rapidly since 80's, which reflected humans activities had great effect on groundwater environment.2. Saturation index of main mineral was calculated, combined regular components contour map and main mineral saturation index contour map to analyzed hydrochemical characteristics of recharge and discharge areas, which indicated that the components content and mineral saturation index of recharge areas were less than that in discharge areas. Along the groundwater flow direction, the closer to the end of the water discharge area the greater the saturation index of minerals. The research of hydrochemical components of three typical travel path indicated that along the water flow direction the components content was rising, which indicated hydrodynamic condition had a certain effect to hydrochemical components.3. Single-factor index analysis and trend analysis method were used to explore the hydraulic connection between karst water systems, and it was found that the correlation coefficient of each indicators was low in eastern suburb and urban areas, which western suburbs and urban areas had a high correlation coefficient of each index, the relevance was better. The correlation of groundwater among Huaneng Road and Povincial Exploration Academe in eastern suburb, Lashan waterworks and Emeishan waterworks in western suburbs and Baotu Spring confirmed this conclusion. Some water samples of eastern industrial suburbs, western suburbs and near the springs were adapted space cluster theory to analyse for the first time, and the clustering results showed that the western suburbs and large karst springs had good clustering effect. East industrial suburb and karst springs had poor clustering. The result provided a new proof to the hydraulic connection research of eastern suburbs-city-western suburbs.The research indicated hydrochemical indexes had significant indication to put out interior hydraulic connection of groundwater system. Meanwhile, the analysis of abnormity points of Politics and Law College in east suburb and Dayangzhuang in western suburbs indicated hydrochemistry field analysis should combined with groundwater flow field, groundwater extraction, aquifer characteristics and other factors.4. Ion proportional coefficient method was adapted, it was considered that the hydrodynamic conditions of groundwater recharge zone were significantly different with discharge areas. On the basis of hydrochemical simulation by PHREEQC, the simulation results indicated calcite and aragonite dissolution and deposition were the main source of Ca2+, gypsum and anhydrite dissolution accounted for a relatively modest proportion.The results indicated human activities, aquifer conditions and groundwater circulation were three main factors to impact the hydrochemical composition changes in Jinan spring area. Indoor static dissolution experiments show that the lithology, intensity of rainfall infiltration, structural conditions and groundwater runoff cycle conditions were four main factors that affect groundwater corrosion. Aquifer lithology, suitable monoclinic structure conditions and human activities were main factors to control the chemical composition of karst water.5. According to the evolution regular and formation mechanism of hydrochemical field in Jinan spring area, proposed the protection Jinan springs must regard both water quality and quantity. Measures of controlling pollution source in recharge-runoff area, reducing the new city sewage to be taken against water quality deterioration. In order to keep springs spewing, based on simulation calculation to optimal exploitation layout by MODFLOW,groundwater safe yield was 18.5×104m3/d, while mesaures of artificial recharge, rain floods using, planting trees were adopted to increase groundwater infiltration, and strengthen water resources management and long-term monitoring of groundwater.