Abstract: The aim of this study is to obtain the hydrochemical characteristics of groundwater in the Xiuwu area of north Henan Province of China. Fourty-two groundwater samples and three surface water samples collected in the wet season of 2018 were analyzed to obtain the hydrochemical characteristics and assess the water quality via mathematical statistics, Piper’s plot, fuzzy mathematics synthesis method, correlation analysis and Gibbs plot. Major factors affecting the hydrochemical characteristics were also investigated. The results are as follows: (1) The content of Na⁺, Ca²⁺, HCO₃^- and SO₄^2- in the groundwater of Xiuwu area was relatively high, and the content of cation was in an order of Na⁺>Ca²⁺>Mg²⁺>K⁺, while anions HCO₃^->SO₄^2->Cl^->NO₃^->F^-. (2) Shallow groundwater presented obvious zoning characteristics, transiting from HCO₃ type and HCO₃·SO₄ type in the northern alluvial fan, to HCO₃·SO₄·Cl type in the front of the fan, and then to SO₄·Cl type, SO₄ type and HCO₃·SO₄ type in the Huangqin River alluvial plain; deep groundwater as a whole was of HCO₃ type. (3) The results of fuzzy mathematics comprehensive evaluation showed that the groundwater quality in the Xiuwu area was good overall yet with pollutions locally. (4) Groundwater chemistry is mainly controlled by rock action and is also affected by evaporation and concentration. Groundwater in some parts is affected by surface water, hydrodynamic conditions and human factors, mainly industrial and mining enterprises. The research results are expected to provide reference for groundwater pollution prevention and water resources protection in Xiuwu area.

Key words: groundwater, hydrochemical characteristics, water quality evaluation, influencing factors, Xiuwu area