Investigation of discharge-area groundwaters for recharge source characterization on different scales: the case of Jinan in northern China

Wang, Jiale; Jin, Menggui; Lu, Guoping; Zhang, Dele; Kang, Fengxin; Jia, Baojie

Investigation of discharge-area groundwaters for recharge source characterization on different scales: the case of Jinan in northern China | Etude des eaux souterraines au niveau de l’aire de décharge en vue de la caractérisation de l’origine de la recharge à différentes échelles: le cas de Jinan dans le Nord de la Chine La investigación de la zona de descarga de agua subterránea para la caracterización de fuentes de recarga en diferentes escalas: el caso de Jinan, en el norte de China 排泄区水文地质信息指示不同尺度地下水补给来源:以中国北方济南地区为例 Investigação de áreas de descarga de águas subterrâneas para a caracterização de fontes de recarga em diferentes escalas: o caso de Jinan, norte da China

2016

Discharge-area groundwater in Jinan, a typical karst region in northern China, was investigated by studying both the hydrological and chemical processes evolving from the recharge in mountainous terrains to the karst-spring outflows in the metropolitan area. Large-scale exploitation of karst groundwater has led to a disturbing trend in the ever-decreasing spring outflow rates and groundwater level. There is insufficient information about the Jinan karst aquifers, which provide the main water sources to meet human demand and to sustain spring outflow. The coupling of hydrological and chemical processes quantifies the flow system through aqueous chemistry characterization of the water sources. This approach is used to study the groundwater flow discharges in different locations and geological settings. The potentiometric data indicated limited vertical connectivity between distinct hydrogeological units and alteration of the recharge regime by the faults and by artificial exploitation. Shallow groundwater primarily belongs to the local flow system, with high nitrate concentration and enriched stable isotopic contents. Thermal groundwater has high concentrations of chloride and total dissolved solids, derived from a regional flow system with the highest recharge altitudes and long residence time. Non-thermal karst water may be attributed to the intermediate flow system, with uniform HCO₃–Ca(Mg) facies and low nitrate concentration. This work highlighted discharge as a fingerprint of groundwater flow conditions and provides a better insight into the hydrogeological system.

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