Identifying the flow pattern and natural recharge at groundwater resource in Dornogobi, Mongolia

What is it about?

The strategic project of economic development in the Dornogobi Province in Mongolia is dependent on water supply. Thus a comprehensive hydrogeological characterization was focused on the Upper Cretaceous multi-aquifer system north of Sainshand City. A conceptual model was developed to discover the groundwater flow pattern essential to correct the setting of the numerical model of groundwater flow created using MODFLOW to assess the natural recharge of the aquifer. The conceptualization was based on geological and hydrogeological characterization. However, especially the evaluation of hydrochemistry proved to be the key factor revealing the principal feature of the groundwater flow pattern, which is the presence of preferential flow zones. These zones allow for intensive transfer of relatively fresh Na(Mg,Ca)‒HCO3 dominated groundwater into discharge areas where it leaks into the Quaternary aquifer. The numerical model suggested an enormous natural recharge of 22 100 m3/d, originating in 64% of the preferential flow zones.

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Why is it important?

Evaluation of groundwater system has fundamental implications for the economic and population growth of the Dornogobi Province in Mongolia. Presented study emphasizes the importance of the combination of hydrogeological and hydrochemical data into the construction of a conceptual model. Manuscript deals with the area where the groundwater flow system is very rarely seen in literature and it deserves to be noticed as a place where the overexploitation may happen soon.