渭河水文情势变化评估及归因分析

Alteration of Hydrologic Regime and Analysis on Its Diving Factors of the Weihe River Basin

河流水文情势关系着河流生态健康,对河流生态系统的完整性和稳定性具有重要影响。采用线性回归法、Mann-Kendall法、累积距平法及双累积曲线法分析了渭河流域咸阳、华县与状头3个水文站径流变化特征(1965—2018年),结合IHA-RVA法综合评估河川径流水文指标改变程度,揭示了人类活动对水文情势的影响。结果表明:1965—2018年渭河主干及子流域北洛河流域年径流量呈显著减少趋势(p<0.05),干流咸阳和华县站年径流减少速率分别为5.5×10^(7)m^(3)/a和6.8×10^(7)m^(3)/a,北洛河状头站年径流减少速率为8.0×106m3/a;咸阳和华县站年径流量突变年份均为1993年,状头站年径流量突变年份为1994年。对比突变前后水文指标变化程度,咸阳、华县与状头站水文整体改变度分别为48%,46%和50%,为中度改变。流量变化改变率及频率改变最为显著,水利工程与水土保持措施是河川水文情势变化的主因。研究结果可为流域水资源可持续利用与水土保持措施合理规划提供理论基础。

Hydrological regime is related to river ecological health and has an important influence on the integrity and stability of river ecosystem. Linear regression method, Mann-Kendall method, cumulative anomaly method and double cumulative curve method were used to analyze the runoff change characteristics of Xianyang, Huaxian and Zhuangtou hydrological stations in the Weihe River Basin from 1965 to 2018. IHA-RVA method was used to comprehensively evaluate the change degree of runoff hydrological indicators and reveal the impact of human activities on hydrological regime. The results show that the annual runoff of the main and sub-basins of the Weihe River showed a significant decreasing trend from 1965 to 2018(p< 0.05). The annual runoff reduction rates of Xianyang and Huaxian stations were 5.5×10^(7)m^(3)/a and 6.8×10^(7)m^(3)/a, respectively, and the annual runoff reduction rate of Beiluo River head station was 8.0×10~6 m~3/a. The abrupt change year of the annual runoff at Xianyang and Huaxian stations was the year of 1993, and the abrupt change year of the annual runoff at Fangtou station was the year of 1994. Compared with the changes of hydrological indexes before and after the mutation, the overall changes of Xianyang, Huaxian and Fangtou stations were 48%, 46% and 50%, respectively, which were moderate changes. Water conservancy projects and soil and water conservation measures were the main causes of the hydrological regime change. The results can provide the theoretical basis for the sustainable utilization of water resources and rational planning of soil and water conservation measures in this basin.