Anhui Province is rich in geothermal water resources, making the study of its hydrochemical evolution and genetic models essential for scientific development and sustainable utilization. This study combines hydrochemical and hydrogen–oxygen isotopic data from different regions of Anhui Province to analyze the hydrogeochemical evolution characteristics and recharge mechanisms of basin-type and mountainous-type geothermal waters. The results show that basin-type geothermal water is predominantly of the Cl–Na type, with water–rock interactions mainly including halite dissolution, gypsum dissolution, dedolomitization, and silicate hydrolysis. The groundwater system is relatively closed off, with slow flow rates. In contrast, mountainous geothermal water is mainly of the HCO₃–Na·Ca, SO₄–Na·Ca, and SO₄–Na types, with water–rock interactions primarily involving calcite dissolution, dolomite dissolution, and gypsum dissolution. Enhanced precipitation infiltration due to fault structures leads to stronger recharge and an open-system characteristic. The genetic models of the two types of geothermal water reveal the structural and recharge mechanisms of thermal reservoirs under different geological settings, highlighting the significant control of geological background on geothermal water formation.

To reduce downstream ecological damage, it is crucial to analyze water and salt sources in saline–alkali farmland drainage and optimize soil salt discharge. This study employs statistical, hydrochemical, and isotope methods to identify controlling factors and characteristics in water bodies during winter irrigation. The results show average TDS values of 0.59, 6.40, and 4.14 g/L for irrigation, phreatic, and drainage water. Irrigation and phreatic water mainly belong to the HCO₃-Ca·Mg·Na and Cl·SO₄-Na·Mg types. Na⁺/(Na⁺ + Ca²⁺) and Cl⁻/(Cl⁻ + HCO₃⁻) values suggest the rock–water interaction and evaporation influences in irrigation water, while evaporation primarily controls phreatic water. The main salt types include NaCl, MgSO₄, Na₂CO₃, and CaCO₃ for irrigation water and NaCl, MgSO₄, Na₂SO₄, and CaCO₃ for phreatic water. These findings lay a research basis for analyzing water and salt sources in farmland drainage during winter irrigation in saline–alkali land.