Application of inverse modeling in a study of the hydrogeochemical evolution of karst groundwater in the Jinci Spring region, northern China

The study of the hydrochemical characteristics and the water–rock interaction of karst groundwater is very important for the rational exploitation of karst groundwater and its pollution control. In this paper, the systematic clustering method was used to analyze the hydrochemical characteristics of different types of groundwater, combined with hydrochemical graphic analysis and correlation analysis to explore the impact of chemical acidic wastewater on the evolution of karst aquifer in the Dawu water source area, northern China. The results show that the chemical acid wastewater, sourcing from discharges/spillages from the local chemical industries, has different degrees of pollution impact on karst groundwater, causing the total hardness of all karst groundwater and the total dissolved solids, Cl− and SO42− in nearly half of the karst groundwater to exceed the quality indexes of class III water in China’s standard for groundwater quality (GB/T 14848-2017). Hydrochloric acid and sulfuric acid in the wastewater can be buffered by the dissolution of carbonate rocks, resulting in a nearly neutral pH (pH-buffering effect) and an increase in Ca2+, Mg2+, Sr, Cl− and SO42− concentrations in karst groundwater.

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Impacts of Artificial Regulation on Karst Spring Hydrograph in Northern China: Laboratory Study and Numerical Simulations

Water ◽

10.3390/w11040755 ◽

2019 ◽

Vol 11 (4) ◽

pp. 755 ◽

Cited By ~ 2

Author(s):

Wu ◽

Shu ◽

Li ◽

Chen ◽

Xu ◽

...

Keyword(s):

Karst Aquifer ◽

Time Lag ◽

Northern China ◽

Flow Fields ◽

Spring Discharge ◽

Karst Groundwater ◽

Karst Spring ◽

Stagnation Points ◽

Recession Coefficient ◽

Laboratory Tank

Karst aquifers produce the world’s largest springs and supply the water resources to about a quarter of the global population while being influenced by high-intensity human activities. Knowledge about spring discharge hydrographs driven by the effects of artificial regulation is essential to develop practical strategies for the management of karst groundwater. Based on hydrogeological conditions of the karst aquifer in Jinan, a two-dimensional laboratory tank was constructed, and a corresponding numerical simulation model was developed to explore how artificial regulation drives spring hydrographs in northern China. The results showed that the spring hydrographs were significantly changed under the effects of artificial regulation. The recession coefficient increased with pumping and decreased with increasing injection rates. The late sub-recession of spring discharge did not obey the exponential recession under the influence of injection. Pumping and injection in conduit zones showed more obvious effects on the recession coefficient in the late sub-recession curves. Groundwater exchange between conduits and fissure zones differed totally for different artificial regulation modes. With continuing rainfall, the flow fields were gradually controlled by rainfall. There was a time lag in the flow fields caused by rainfall. Under the stress of exploitation at different positions, stagnation points appeared at different locations in fissure zones, and locations of stagnation points were highly dependent on the positions of pumping wells. These findings are essential for better management of karst groundwater and karst spring protection.

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