Identifying surface water evaporation loss of inland river basin based
on evaporation enrichment model
Abstract
Accurately quantifying the evaporation loss of surface water is
essential for regional water resources management, especially in arid
and semi-arid areas where water resources are already scarce. The
long-term monitoring of stable isotopes (δ18O and δ2H) in water can
provide a sensitive indicator of water loss by evaporation. In this
study, we obtained surface water samples of Shiyang River Basin from
April to October between 2017 and 2019. The spatial and temporal
characteristics of stable isotopes in surface water show the trend of
enrichment in summer, depletion in spring, enrichment in deserts and
depletion in mountains. The Surface Water Line (SWL) has been defined by
the lines: δ2H=7.61δ18O+14.58 for mountainous area, δ2H=4.19δ18O-17.85
for oasis area, δ2H=4.08δ18O-18.92 for desert area. The slope of SWL
shows a gradual decrease from mountain to desert, indicating that the
evaporation of surface water is gradually increasing. The evaporation
loss of stable isotopes in surface water is 24.82% for mountainous
area, 32.19% for oasis area, and 70.98% for desert area, respectively.
Temperature and air humidity are the main meteorological factors
affecting the evaporation loss, and the construction of reservoirs and
farmland irrigation are the main man-made factors affecting the
evaporation loss.