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›› 2016, Vol. 39 ›› Issue (3): 573-581.

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Hydrological reconstructions of the Holocene Palaeoflood in the Tianshui East Reach of the upper Weihe River

SHI Bin-nan, HUANG Chun-chang, PANG Jiang-li, ZHA Xiaochun, LIU Tao, LIU Wen-jin   

  1. College of Tourism and Environmental Sciences, Shaanxi Normal University, Xi'an 710062, Shaanxi, China
  • Received:2015-11-23 Revised:2016-01-28 Online:2016-05-25

Abstract: In this paper, palaeoflood hydrological investigations were carried out in the upper reaches of Weihe River which is a major tributary of the Yellow River and noted for the earliest cradles of Chinese civilization. Four bedsets of Holocene palaeoflood slackwater deposits were found interbedded within the cliff riverbanks at HNC profile of the river. During field investigations, palaeoflood SWD was identified by a variety of scientific sedimentological criteria including color, texture and structure of the extraordinary flood deposits; besides, the chronology, sedimentary features, and hydrological characteristics were also observed and recorded. Later in laboratory, characteristics of the particle-size distribution, magnetic susceptibility, percentage composition of calcium carbonate and loss on ignition were further analyzed. Results show that these four bedsets slackwater deposits recorded the extraordinary floods happened between 1800-1600 a BP on the river over the Holocene by using Optically Stimulated Luminescence (OSL) dating method in combination with pedostratigraphy correlations, checking by historical relics of the human from profiles. This indicates that the extraordinary floods happened during the dynasties of Eastern Han to Three Kingdoms in Chinese history, when grievous floods and droughts were caused by many years of price war according to the record of Historical documents. The estimated results indicated that the palaeoflood peak discharges were between 11420 m3·s-1 and 20100 m3·s-1 by using HEC-RAS model. Thirteen cross-sections were selected in one kilometer along the river reach, and the roughness values included three segments, channel, left riverbank and right riverbank. The sensitivity test on the model showed an error between -10.99% to 8.79% with the same hydrological parameters, which was much smaller than that by the slope-area methods. Relation between catchment area and the peak discharges indicates that the results were reasonable and scientific. Using the palaeoflood discharge data, gauged data and historical flood information, peak discharges-frequency curves of the Nanhechuan gauge station on Weihe River at 10000 year time scale were analyzed. This research improved the accuracy of the flood frequency calculation and prolonged flood data time series from decades to millennia in Weihe River. The results provided important basis for this region's hydraulic engineering construction, traffic engineering construction, water resource management, the flood control, and disaster mitigation project.

Key words: palaeoflood, Holocene, HEC-RAS model, hydrological reconstruction, Weihe River

CLC Number: 

  • P531