金沙江支流关河流域水文情势评价

Evaluation of hydrological situation in Guanhe Basin,a tributary of Jinsha River

水文情势变化是影响河流生态系统、功能的主要驱动力。为研究人类活动影响前后关河流域水文情势变化,在研究豆沙关水文站相关数据的过程中,以1959—2018年间的数据为参考资料,结合Mann-Kendall法分析水文数据的演变趋势,水文指标变化范围法分析年径流输沙年际、年内变化趋势及其水沙单项水文指标改变度;在分析该地气候变化情况时,运用双累积曲线法,同时,为了更好地分析影响径流水沙的变化的因素,特别是对人类活动因素进行分析,引入累积量斜率变化率法。结果显示:1)1959—2018年,豆沙关水文站多年平均流量和年降水总量呈下降趋势,趋势不显著;年平均输沙率呈下降趋势,趋势显著;2)在人类活动的干扰下,该流域的流量发生了一定改变,体现为月均流量值变化明显,与之前相比,变化幅度已经突破34%;月均含沙量值水文改变度达到40.58%,呈中度改变;3)人类活动、年降水量、年潜在蒸发量分别对年输沙量的贡献率分别为69.22%、29.66%和1.12%,1996—2018年总减沙量为2564.66万t,平均每年为116.57万t,分析造成输沙变化的因素可知,虽然许多因素都具有一定影响作用,但人类活动是最为核心且影响最大的因素。

[Background]The Jinsha River is the main sand-producing area in the upper reaches of the Yangtze River.Studying the characteristics and driving factors of water-sediment changes in the Jinsha River is of great significance to the implementation of soil and water conservation measures in the future,the regulation of the relationship between water and sand in the Yangtze River,and the rational use of water resources.[Methods]This paper selects the water and sediment data of the Doushaguan Hydrological Station from 1959 to 2018 for a total of 60 years,and uses the Mann-Kendall trend analysis and the hydrological index change range method(IHA/RVA)to determine the annual runoff and annual sediment transport.The double cumulative curve method and the cumulative slope rate of change method were used to quantitatively calculate the impact of human activities on the water and sand regime.[Results]1)The multi-year average discharge and total annual precipitation at Doushaguan Hydrological Station from 1959 to 2018 showed a downward trend,but the trend was not significant;the annual average sediment transport rate showed a downward trend,with a significant trend.2)After soil erosion control,the hydrological change degree of the monthly average discharge value of Doushaguan Station Hydrological Station reached 34%,showing a moderate change;the hydrological change degree of the monthly average sediment content value reached 40.58%,showing a moderate change.3)Human activities,annual precipitation,and annual potential evaporation contribute 69.22%,29.66%,and 1.12%to the annual sediment transport,respectively.The total sediment reduction affected by human activities is 2564.66×104 t,and average annual amount was 116.57×104 t Human activities were the most important factor influencing changes in sediment transport of Guanhe Basin.[Conclusions]This paper analyzes the change trend of water and sediment before and after the impact of human activities in 1996,and the degree of change in the hydrological indicators of the Guanhe Basin for a total of 60 years in the two phases,and further explores the changes in water and sediment regimes before and after soil erosion control.Provide reference for ecological protection and restoration of Guanhe River.