Changes of Water Discharge between Datong and the Changjiang Estuary during the Dry Season
Received date: 2002-04-07
Revised date: 2002-11-02
Online published: 2003-03-25
Supported by
National Natural Science Foundation of China, No. 49971071; Shanghai Priority Academic Discipline
Based on data from hydrometric stations and other documented sources about the hydro-engineering works downstream from Datong (the tidal limit from the East China Sea), this paper presents a preliminary study on water discharge changes between Datong and Xuliujing during the dry season. The natural hydrological processes and human factors that influence the changes of water discharge are analyzed with the help of the GIS technology. The investigations indicate that the water-extracting engineering projects downstream Datong had totaled to 64 in number by the end of 2000, with a water-extraction capacity up to 4626 m3/s averaged in a tidal cycle. The water abstractions from the Changjiang River downstream Datong have become the most important agent that may cause large and episodic drop in water discharge downstream Datong during dry season. The potential magnitude in water discharge changes under different climatic and hydrological conditions in dry season and its influence on the discharge into the sea are estimated based upon records of water extractions and parameters of engineering capacity. The results were calibrated with the actual data. The future trend of changes in water discharge to the sea during the dry season was discussed according to the historical data and the newly built engineering projects. The results show that the water extractions in dry season before 2000 downstream Datong had exerted remarkable impacts on discharges into the sea only during the extremely dry year like the period 1978-1979, when the monthly mean discharges all decreased over 490 m3/s. The decrease in January and February accounted for about 7% of the total discharge recorded at Datong. It is expected that the water extractions will continually increase in the coming decades, especially during dry years, and will have a far-reaching effect on the changes of water discharge from the Changjiang into the sea. The decrease in monthly mean water discharge is estimated to be over 1,000 m3/s.
Key words： the Changjiang Estuary; dry season; water discharge; water resources
ZHANG Erfeng, CHEN Xiqin . Changes of Water Discharge between Datong and the Changjiang Estuary during the Dry Season[J]. Acta Geographica Sinica, 2003 , 58(2) : 231 -238 . DOI: 10.11821/xb200302010
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