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Description
To understand the hydrological regime of the surface water in Kanu Woralaksaburi district, Kamphaeng Phet province, the rainwater and surface water were analyzed on the isotopic variability of hydrogen (δ 2H) and oxygen ( δ18O) collected over 3 years from 2015-2017. Surface water evaporation was verified on the basis of the isotope composition results. Based on a total of 213 rainwater samples and 152 surface water samples, stable isotope analysis was carried out and the Local Meteoric Water Line (LMWL) was defined as δ2H = 7.703 δ18O -1.333, R2 = 0.952 while the Local Evaporation Line (LEL) of surface water was δ2H = 5.318 δ18O -17.618, R2 = 0.935. It was observed that the isotope compositions of surface water have a linear relationship with precipitation (R2 = 0.935). However, the small slope of 5.318 indicated the enrichment effect of evaporation. Depleted isotopic compositions of surface water revealed in wet season and enriched δ2H and δ18O were found in dry season with less precipitation, lower humidity and higher temperature. Presented data imply that the isotopic composition of surface water in semi-arid area of Kamphaeng Phet is predominantly due to rain intensity and evaporative loss.
