Hydrological reconstruction of extreme palaeoflood events 9000-8500 a BP in the Danjiang River Valley, tributary of the Danjiangkou Reservoir, China
Hydrological reconstruction of extreme palaeoflood events 9000-8500 a BP in the Danjiang River Valley, tributary of the Danjiangkou Reservoir, China
复制标题
丹江口水库支流丹江流域9000-8500 a BP极端古洪水事件的水文重建
DOI：
10.1007/s12517-020-5132-3
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发表时间：
2020
影响因子：
--
通讯作者：
Ma Yugai
中科院分区：
文献类型：
--
作者：
Li Xiaogang;Huang Chunchang;Zhang Yuzhu;Pang Jiangli;Ma Yugai
丹江是丹江口水库的主要支流，因目前的国家南水北调工程而闻名。在丹江流域进行了古水文调查。根据沉积判据和分析结果，在河堤全新世黄土层序中发现了一套古洪水平流沉积层。这些古洪水SWDs是由河岸洪水的悬浮泥沙负荷沉积而成。根据光学模拟发光（OSL）测年和土壤地层对比，这些极端古洪水事件的年代在9000 ~ 8500 a BP之间。采用静水流深度法计算了404.4 ~ 412.5 m之间的古洪峰阶段。利用HEC-RAS模型计算了古洪峰流量在8570 ~ 23350 m3/s之间。这些结果将丹江洪水数据序列扩展到1万年的时间尺度。古洪水事件发生的时间与同期8500 a BP的全球气候事件吻合较好，这一时期季风气候由全新世早期的干燥气候转变为全新世中期的最佳气候条件。这些研究结果将在洪水风险评估、水资源开发、全球气候变化对丹江口水库流域水文系统的影响等方面发挥重要作用。
The Danjiang River, a major tributary of the Danjiangkou Reservoir, is famed for the current national South-to-North Water Diversion project. Palaeohydrological investigations were carried out in the Danjiang River valley. A set of palaeoflood slackwater deposit (SWD) beds was identified embedded in Holocene loess soil sequences within riverbank cliffs based on sedimentary criteria and analytical results. These palaeoflood SWDs were deposited from the suspended sediment load of overbank flooding. These extreme palaeoflood events were dated to between 9000 and 8500 a BP from optically simulated luminescence (OSL) dating and pedostratigraphical correlation. The palaeoflood peak stages were calculated between 404.4 and 412.5 m using the slackwater flow depth method. The palaeoflood peak discharges were calculated between 8570 and 23,350 m3/s using the HEC-RAS model. These results have extended the flood data sequence of the Danjiang River to a 10,000-year time-scale. The ages of the palaeoflood events coincide well with the contemporaneous global climatic events at 8500 a BP, a time that the monsoonal climate shifted from the early Holocene dry conditions to the mid-Holocene climatic optimum. These findings will play an important role in flood risk estimation, the development of water resources, and will be significant in understanding the effects global climatic variations on hydrological systems in catchment of the Danjiangkou Reservoir.