Estimation of evaporation and irrigation return flow in arid zones using stable isotope ratios and chloride mass-balance analysis: Case of the Euphrates River, Syria

摘要: Abstract Stable isotope ( 18 O and 2 H) ratios were measured together with electrical conductivity (EC) values chloride concentrations on a monthly basis at 12 stations along the Syrian portion of Euphrates River during period 2004–2005. systematically increased distance downstream most significant enrichment occurring Al-Assad Lake. This systematic increase could be due to: (1) evaporation from river its tributaries (2) drainage return flows irrigation water via groundwater system. Based integral stable isotopes in water, amount lost by Lake was estimated to about 1.93–2.15 billion m 3 using H, respectively. On budget, computed component input through riverbed flow varies spatially 70% less than 1%, depending extent exercised course.