椒江流域水沙变化特征及人类活动影响

在人类活动的影响下，径流和泥沙过程的变化受到越来越多人的关注。研究椒江流域水沙变化特征及人类活动影响因素，对椒江流域生态保护和高质量发展具有重要意义。利用椒江流域降水、径流、输沙和遥感影像等长期监测数据，采用多种方法综合分析椒江流域降水、径流和输沙演变特征，包括对椒江流域水文观测资料进行线性回归趋势分析，使用Mann-Kendall突变检验法、滑动t检验法、距平累积曲线法和双累积曲线法进行水文序列的突变检验，使用小波和功率谱进行水文序列的周期分析。在此基础上，采用线性回归方法估算人类活动和气候变化对椒江流域输沙变化的贡献率，最后讨论了人类活动对椒江流域水沙变化的影响。结果表明：椒江降水量存在2～3、4～5、8～9和15～18 a周期；径流量存在2～3、8～9、14～15和18 a周期；输沙量存在2～3、8、12～15和19 a周期。永安溪、始丰溪年降水量、年径流量和始丰溪年输沙量没有显著变化，永安溪输沙量显著减少，63 a间下降了28%。人类活动对永安溪输沙减少的贡献率为86.5%～98.7%，对始丰溪输沙变化的贡献率为50.3%～83.2%。椒江流域水库建设使得年内流量高峰期由6月份向8、9月份发生转移，起到了很好的“蓄峰”作用。流域内土地利用/覆被发生的显著变化以及植被覆盖度的上升降低了流域产沙能力、减少了河流输沙量。

Characteristics and influencing factors of water and sediment changes in Jiaojiang River Basin

Under the influence of climate change and human activities, more and more people pay attention to the changes of runoff and sediment processes. It is of great significance to study the characteristics and influencing factors of water and sediment changes in Jiaojiang River Basin, Zhejiang, China, for ecological protection and high-quality development. Based on the long-term monitoring data of precipitation, runoff, sediment transport, and remote sensing images of the basin, we comprehensively analyzed the evolution characteristics of precipitation, runoff, and sediment transport in the basin using various methods, including linear regression trend analysis of hydrological observation data, catastrophe test of hydrological series by Mann-Kendall catastrophe test, sliding T test, anomaly cumulative curve method, double-cumulative-curve method, and periodic analysis of hydrological series by wavelet and power spectrum. Moreover, the linear regression method was used to estimate the contribution rate of human activities and climate change to the sediment transport change in the river basin. At last, the influence of human activities on the water and sediment change in the river basin was discussed. The results show that 2–3 years, 4–5 years, 8–9 years and 15–18 years of precipitation cycles in the two tributaries; runoff cycles of 2–3 years, 8–9 years, 14–15 years and 18 years; and sediment transport cycles of 2–3 years, 8 years, 12–15 years, and 19 years present in Jiaojiang River Basin. The annual precipitation, annual runoff and annual sediment transport of the tributaries Yongan River and Shifeng River had no significant changes, and the annual sediment transport of Yongan River decreased by 28% in the past 63 years from 1957 to 2021. The contribution rate of human activities to the decrease of sediment transport in Yongan River was 86.5%–98.7%, and that in Shifengxi was 50.3%–83.2%. In addition, reservoir construction played a very good role as a buffer. Significant changes in land use/cover reduced the soil erosion in Jiaojiang River Basin with less sediment generation. The vegetation coverage in watersheds of the two tributaries was gradually increasing, which reduced the sediment yield in the watersheds to some extents.