Spatio-temporal hydrochemistry of two selected Ramsar sites (Rara and Ghodaghodi) of west Nepal

The present study was conducted in two Ramsar sites, Lake Rara and Lake Ghodaghodi, of the western Nepal covering pre-monsoon and post-monsoon seasons of 2019 to find out the dynamics of the hydrochemistry. A total of 11 major ions (Na⁺, K⁺, Ca²⁺, Mg²⁺, NH₄ ⁺, F^-, Cl^-, SO₄ ^2-, NO₃ ^-, NO₂ ^-, HCO₃ ^-) along with six on-site parameters (temperature, pH, electrical conductivity, total dissolved solids, dissolved oxygen, and turbidity) were sampled in replicates from 18 sites in Lake Rara and 13 sites in Lake Ghodaghodi. Major ions were analyzed using ion chromatography including field and procedural blanks to maintain quality standards, whereas on-site parameters were measured by using standard multi-meter probes. The most dominant cation and anions were Ca²⁺ and HCO₃ ^- in both lakes indicating rock dominance through carbonate weathering as the primary source of dissolved ions in the lake waters. Further analysis indicated that Rara belongs to Ca(Mg)HCO₃ and Ghodaghodi belongs to Ca-HCO₃ type. The higher concentrations of Na⁺ and Cl^- during the post-monsoon indicates a possibility of long-range marine transport through monsoon precipitation.