Preliminary analysis on evaporation rules of high-salinity phreatic water in arid area

In order to analyze the evaporation rules of high-salinity phreatic water in arid area, monitoring of phreatic water evaporation with different total dissolved solids (TDS) (0.8 g/L, 30 g/L and 100 g/L), lithological characteristics of unsaturated zones (fine sand and silty clay) and depth of groundwater (0 m, 0.5 m,1.0 m, 2.0 m and 3.0 m) were carried out at groundwater balance experiment station in Changji, Xinjiang from 1st April, 2012 to 31st March, 2014. The results showed that the influence of lithological characteristics of unsaturated zones on the evaporation of phreatic water with high salinity was basically the same as in freshwater when the groundwater depth was larger than 0.5 m. The influence of variation of lithological characteristics of unsaturated zone on phreatic water evaporation was far less than the common influence of TDS and atmosphere evaporation potential on phreatic water evaporation when the groundwater depth was 0.5 m and TDS was 30 g/L. Annual phreatic water evaporation had an opposite trend as atmospheric evaporation capacity E_Φ20 with groundwater depth being 0 m, TDS being 100 g/L and lithological characteristics of unsaturated zones being silty clay. Phreatic water evaporation decreased gradually with the increase of TDS during non-freezing period with groundwater depth being 0.5 to 1.0 m. The inhibition effect of TDS variation on phreatic water evaporation lagged behind with the groundwater depth of 3.0 m.