济南四大泉群泉水补给来源混合比探讨

Mixing ratios of recharging water sources for the four largest spring groups in Jinan

济南泉水众多闻名于世,人类活动造成泉水断流。为恢复名泉,多年来一直实施地下水自备井限采、集中开采的水源地禁采、回灌补源等措施,但保泉效果并不明显。根据泉水位观测、示踪试验、水质指标测试、岩溶发育程度分析、数理统计等方法,研究泉水补给来源的混合比例。研究结果表明:泉水位及泉水电导率动态变化特征揭示泉水补给来源存在季节性差异,丰水期泉水以东南方向管道流补给为主,枯水期泉水以西南方向裂隙流补给为主;岩溶水系统排泄区的水位动态与泉水位具有明显的相关性,奥陶系灰岩补给区地下水位与泉水位的相关性高于张夏组岩溶水水位与泉水位的相关性,枯水期在张夏组灰岩含水层进行回灌补源并不能遏制泉水位下降的势态;根据42组水质资料计算,泉水的Ca^(2+)、Mg^(2+)、Cl^-、SO4^(2-)、总硬度等常规离子组分含量介于寒武系张夏组岩溶水和奥陶系岩溶水之间,四大泉群流量中,来自张夏组含水层的补给比例占11%～32%,凤山组—奥陶系含水层的补给比例占24%～60%,历阳湖占5%～10%,兴济河占0～6%,玉符河占1%～8%,市区回灌对五龙潭的流量有重要影响。可见,北方岩溶发育极其不均,泉水动态变化反映出北方岩溶的管道流与裂隙流并存,济南保泉回灌补源地点宜选择在奥陶系灰岩分布区。

Jinan,a city well known for its numerous springs,is now faced with spring dry out caused by human activities.In past years,the city has taken measures to protect the famous springs by limiting extraction from self-supply wells,prohibiting extraction of centralized water supply sources,artificial recharging,etc.,with no apparent success.In this paper,the mixing ratios of different recharging water sources were studies through spring level observation,tracer experiment,water quality test and analysis of karst development,complemented by mathematical modeling.The characteristics of changes of the spring level dynamics and electrical conductivity revealed that the source of recharge changes according to the season.Specifically,the springs were recharged mainly by the pipe flow from the southeast in wet seasons,and by the fissure flow from the southwest in dry seasons.The results show：in the discharging area of the karst water system,distinct correlation exists between the groundwater level and spring level dynamics;the groundwater level in Ordovician limestone correlates better with spring level than the karst water level in limestone of the Cambrian Zhangxia Formation;and artificial recharge in the Zhangxia Formation can not halt the declining trend in spring level.Based on 42 sets of data,our calculation shows that the contents of conventional ions in springs,such as Ca2＋,Mg2＋,Cl- and SO42-,and total water hardness,lied between that of the karst waters of the Cambrian Zhangxia Formation and Ordovician.Moreover,in the flow of the four large spring groups,11%-32% came from the recharge of the Zhangxia Formation,24%-60% from the recharge of the Fengshan Formation and Ordovician,5%-10% from the Liyang Lake,0-6% from the Xingji River,and 1%-8% from the Yufu River.Artificial recharge in urban areas,therefore,would significantly influence the Five-Dragon Pool.In conclusion,the northern karst developed heterogeneously;pipe flow coexisted with fissure flow as indicated by changes of spring level dynamics;and artificial recharge should be located in areas where Ordovician limestones are distributed.