Acta Geographica Sinica ›› 2019, Vol. 74 ›› Issue (9): 1733-1744.doi: 10.11821/dlxb201909003

• Surface Processes • Previous Articles     Next Articles

Characteristics of hydrogen and oxygen isotopes in precipitation and runoff and flood hydrograph separation in an urbanized catchment

XIE Linhuan1,JIANG Tao1(),CAO Yingjie2,3,ZHANG Desheng1,LI Kun1,TANG Changyuan1,2,3   

  1. 1. School of Geography and Planning, Sun Yat-sen University, Guangzhou 510275, China
    2. School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
    3. Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou 510275, China
  • Received:2018-04-25 Revised:2019-07-14 Online:2019-09-25 Published:2019-09-25
  • Contact: JIANG Tao E-mail:eesjt@mail.sysu.edu.cn
  • Supported by:
    National Natural Science Foundation of China(41501512);National Natural Science Foundation of China(41471020);Natural Science Foundation of Guangdong Province, China(2017A030313231);Science and Technology Program of Guangzhou, China(201510010300)

Abstract:

In order to study the response characteristics of precipitation-runoff under the influence of human activities, this paper took Shima River, a typical urbanized catchment in the Pearl River Delta as the research area. Daily samples of precipitation and river water were collected from January to December and hourly samples were collected during three typhoon rainstorms in 2017. Based on the stable isotope data (δD, δ 18O), the characteristics of hydrogen and oxygen isotopes were analyzed. Two-component isotope-based hydrograph separation was used to study the contribution of pre-event water and event water to the runoff process during three typhoon events. The results showed that δD and δ 18O in precipitation ranged from -105.10‰ to 9.98‰ and -14.80‰ to -0.55‰, respectively, and the annual weighted mean values were -57.88‰ and -8.61‰. The Local Meteoric Water Line was δD=7.70δ 18O+8.61(R 2=0.98). δD and δ 18O in river water ranged from -91.23‰ to -15.96‰ and -12.66‰ to -4.01‰, respectively. δD-δ 18O basically fell on the LMWL indicated that precipitation was the main source of runoff in the Shima River catchment. During the three typhoons, the proportion of event water was 59.7%, 55.0% and 69.4%, respectively, which was higher than that of pre-event water. In the early stage of flood, pre-event water and event water increased synchronously. In the late stage of flood, the proportion of event water increased gradually which was more than 80% during the peak period. This indicated that the increase of impervious areas in the urban regions would significantly alter the hydrological cycle. The results of this study could provide the theoretical foundations for hydrological forecast of urbanized basins in Pearl River Delta.

Key words: hydrogen and oxygen isotopes, two-component mixing model, hydrograph separation, urbanization, Shima River catchment