三峡水库下游水沙情势变化及影响因素分析

为定量评价三峡水库下游水沙情势变化并分析其影响因素,采用基尼系数分析了宜昌站1952～2016年径流量与输沙量年内分配均匀度,运用Mann-Kendall非参数检验、滑动T、累积距平法确定了水沙年内分配均匀度的变化趋势及其突变年份,进一步将水文要素划分为汛期(6～10月)与非汛期(11月～次年5月),并采用累计量斜率变...

Analysis of Variation of Water and Sediment Regime and Its Influencing Factors in the Lower Reaches of the Three Gorges Reservoir

In order to quantitatively evaluate the change of water and sediment regime in the lower reaches of the Three Gorges Reservoir and analyze the influencing factors, the Gini coefficient was used to analyze the annual distribution uniformity of runoff and sediment discharge in Yichang Station from 1952 to 2016. The Mann-Kendall nonparametric test, sliding T method and cumulative anomaly method were used to determine the change trend and mutation year of annual distribution uniformity of runoff and sediment discharge. Furthermore, the hydrological elements were divided into flood season(June-October) and non-flood season(November-May of the next year), and the contribution rate of climate factors and human activities to the runoff and sediment discharge changes in flood season and non-flood season of Yichang Station was quantitatively evaluated by using the cumulative slope change rate method;The river impact method was used to quantitatively evaluate the change degree of water and sediment regime in Yichang. The results show that the annual distribution of runoff in the downstream of the Three Gorges reservoir is more and more uniform, and the annual distribution of sediment transport is more and more uneven;The annual distribution uniformity of runoff and sediment discharge showed a significant downward and upward trend, respectively. According to the variation of annual distribution uniformity, the runoff in flood season and non-flood season changed abruptly in 2002, and the sediment discharge in flood season and non-flood season changed abruptly in 1978 and 2002. Human activities are the main influencing factors of runoff and sediment discharge in the lower reaches of the Three Gorges reservoir, while climate change has little impact on runoff and sediment discharge. The contribution rate of human activities to the runoff and sediment discharge in the downstream of the Three Gorges reservoir is more than 70%. The runoff in flood season and non-flood season in the downstream of the Three Gorges reservoir are 0.69 and 0.86 after 2002, respectively, reaching moderate change and mild change;The sediment discharge in flood season and non-flood season after 2002 are 0.08 and 0.02, respectively, which have reached a serious change.