DU Kang1, ZHANG Beiying1, LI Kai2, LI Linjuan1
(1. School of Geography, Geomatics and Planning, Jiangsu Normal University, Xuzhou 221116, China;
2. College of Grassland Agriculture, Northwest A&F University, Yangling 712100, China)
Abstract: In order to investigate the characteristics of hydrogen and oxygen isotopes in different water bodies and the recharge and conversion relationship between water bodies in typical loess hilly regions, and to use water resources rationally in arid regions, precipitation, river water, groundwater, and soil water samples around Ansai Dun Mountain, Yan'an city, were collected from June to November in 2019. Stable isotope technology and mixed model were used to explore the hydrogen and oxygen isotope characteristics of different water bodies in the study area and water cycle conversion relationship. The results showed that: river water and groundwater in the study area are enriched with hydrogen and oxygen isotopes compared with soil water. The instability of D and 18O content in each water body decreased in orders of precipitation >soil water > river water > ground water. The hydrogen and oxygen isotopes of precipitation, soil water and river water changed greatly with time, and were more depleted in August and November than in other months, the isotopic content of groundwater is stable. Due to the intense nonequilibrium evaporation, the slope and intercept of evaporation line of soil water, river water and groundwater are all smaller than that of atmospheric precipitation line, among which soil water is the smallest. The contribution of precipitation and groundwater that recharge rivers are 32.54% and 67.46%, respectively. The proportion of groundwater recharged by soil water and river water was 72.35% and 27.65%, respectively. The main recharge source of groundwater in the study area is soil water, and the main recharge source of river water is precipitation.
Key words: hydrogen and oxygen stable isotopes; precipitation; soil water; conversion ratio; mixed model
EARTH AND ENVIRONMENT Vol.49, No.3, Tot No.341, 2021, Page 270-276