Study On The Character Of Groundwater Geochemistry And Its Defence Capacity To Contamination In The Karst Spring Area Of Jinan

Jinan is a travel city with mountain and water and it is famous for Spring in the world. Many tourist in the world are attracted to Jinan by Spring. With population increasing and economy development, the Spring is faced with not only exhausted but also pollution. Protecting the Spring and grounwater supply is a chief task. Therefore, it is very important to implement the protection and control of groundwater resources. Hydrochemistry evolvement character of groundwater and Groundwater vulnerability to pollution were systematically analyzed and assessed in this paper.The groundwater quality in rainy period of 2005 and in drought period of 2006 was evaluated using synthetic evaluation method. The result indicated: Karst groundwater quality was better than shallow groundwater quality, and shallow groundwater was liable to pollution; 72%(in rainy period of 2005) and 86.96%(in drought period of 2006) karst groundwater was good with water quality ofⅠorⅡorⅢclass level, but 57.14%(in rainy period of 2005) and 40%(in drought period of 2006) shallow groundwater was good with water quality ofⅠorⅡorⅢclass level; Shallow groundwater quality was all right in recharge area and was not good in discharge area; Karst groundwater pollution was spot or small area. Groundwater quality was close correlation with human activities. Groundwater hardness, NO3- and TDS were the main pollutants in Groundwater now.Hydrochemistry and stable isotope of groundwater was systematically analyzed by AquaChem and Grapher in this paper. Combining with topography and hydrology condition, this paper analyzed thoroughly different recharge source of groundwater in different area, and found out the hydraulic contact between Karst groundwater and shallow groundwater. The result indicated: Karst groundwater in discharge area was provided with character of recharge area, that indicated precipitation infiltrated to karst groundwater directly in bare carbonate rock area. Shallow groundwater was main from precipitation infiltrating in city zone and east suburb, but main from karst groundwater top replenishment and surface water in west suburb and Pingandian area. The research found out the area of karst groundwater top replenishment enlarged than research before.Based on the studies of European karst groundwater vulnerability to pollution assessement method, PI method——the karst groundwater vulnerability to pollution assessement factor system——was systematically analyzed in this paper. Combining with groundwater condition of the study area, karst groundwater vulnerability to pollution was assessed and regionated by Arcgis. The result showed that karst groundwater vulnerability to pollution subarea was coherent with stratum lithology, groundwater embedding condition, topographty gradient.