| Jinan City is famous for numerous karst springs; spring water is a good “city card” and history culture carrier. With the rapid development of social economy and the increase of population, Jinan's springs have been influenced by it. The crisis of spring cutoff has caused widespread concern. In this paper, taking Jinan four large springs as the main research object,based on the analysis of geological and hydrogeological condition in Jinan area, using methods of spring water dynamic monitoring, tracing experiment, chemical analysis of water,erosive experiment of limestone, and so on, the two aspects of hydrogeochemical field and hydrodynamic fields were studied. In this research, the differences and similarities of the recharge resources of four large springs are illustrated, the ratios of different recharge water contributing four large springs is calculated, a spring water table prediction model is established for Baotu Spring to guide the work of protection of spring, and some protection measures are put forward. There is a certain theoretical and practical significance in this research. The main results and innovative points are as follows:(1)The type of groundwater table dynamic curve shows the development degree of Jinan's karst is relatively high. The spring water level is very sensitive to the effects of precipitation and human influence. One millimeter effective rainfall can cause Baotu Spring water level rise by 0.0038 m.(2)The direction of recharge water resources is different between Baotu Spring and Black Tiger Spring. Baotu Spring is mainly recharged by the south and southwest, but Black Tiger Spring is mainly recharged by the south and southeast in Baotu Spring area.(3)Due to the good positive correlation between spring water level and spring discharge,a linear equation is established to use the spring water level to replace spring discharge, which is substituted into the boussinesq equations, obtaining the attenuation coefficient ? show that the karst development of Jinan's karst water system is vertical zonality, the karst development degree from top to bottom could be “strongest”-“stronger”-“strong”-“weakest”- “weak”.(4)The chemical components concentrations of groundwater in Zhangxia formation aquifer in the south of Baotu spring area are lower than in Fengshan formation andOrdovician limestone aquifer, but higher than in the discharge area in north of Baotu spring area. The phenomenon illustrates the springs water is recharged by the both. The dynamic characteristics of springs water electrical conductivity in the discharge area show that there are two groups in origin types and recharge resources types, the first group is Tanxi Spring and Pearl Spring, the second group is Baotu Spring and Black Tiger Spring. The flow route of water supply of the first group is further than the second.(5)The spatial distribution characteristics of spring water electrical conductivity in the discharge area are that from south to north the electrical conductivity gradually decreases. The main reason is that the mixed ratios of recharge water resources contributing four springs are different. The water of Baotu Springs group and Black Tiger Springs group is mixed by large proportion of shallow aquifer(Fengshan formation and Ordovician limestone aquifer), The water of Five Dragon Springs group and Pearl Springs group is recharged by large proportion of Zhangxia formation aquifer. The proportion of recharge water resources contributing four large springs is calculated.(6)The dynamic characteristics of springs water temperature reveal that water supply depth of Baotu Spring is relatively similar with Black Tiger Spring, and the recharge water resources are mainly from the shallow aquifer; Tanxi Spring's is similar with Wangfu Spring's,and the recharge water resources are mainly from the deep aquifer.(7)Baotu Spring recharge water from zhangxia aquifer accounted for 25%,Fengshan formation~ ordovician aquifer accounted for 40%, Liyang lake accounted for 10%, Xingji river accounted for 6%, Yufu river accounted for 8%. Black Tiger Spring recharge water from zhangxia aquifer accounted for 27%, Fengshan formation~ ordovician aquifer accounted for66%, Liyang lake accounted for 6%, Yufu river accounted for 1%. And city artificial recharge had important influence on Five Dragon Pool and Pearl Spring.(8)In discharge area, there occurs strongly mixed corrosion, so karst development is very strong. According to the tracing test results, molybdenum concentration duration curves could be divided into “single-peak type”, “double-peak type”, “three-peak type”, and“multi-peak type”, which illustrate the types of karst run-off channels contain “single-tube type”, “single-tube and pool type”, “multi- tube type”, “multi- tube and pool type”,showing that the types of karst development contain dissolution pore, fissure, dissolutionfissure, pipe, karst cave.(9)Prediction Model of Karstic Large Spring water level dynamic coupling multiple factors in Jinan is established for Baotu Spring to guide the work of protection of spring.Combined with the research content, artificial recharge and water seepage channel protection are the important measures of spring protection at the present stage; the suitable amount of artificial recharge water is 293,000 m3/d; The depth range of the development and utilization of engineering construction in the urban area of Jinan is less than 6m, and in the area near the big four Springs groups is never more than 2m. |
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