赣江中游禾水河水沙变化特征及影响因素分析

Analysis of water and sediment variation characteristics and influencing factors in Heshui River along middle reaches of Ganjiang River

【目的】探明赣江中游左岸一级支流禾水河水沙变化驱动因素,为赣江中游土壤侵蚀治理、土地利用和功能调整等工作提供科学依据。【方法】采用Mann-Kendall检验法、Pettitt检验法、累积距平法、双累积曲线法、累积量斜率变化率法对河流控制水文站上沙兰站1980—2019年降雨量、径流量及输沙量数据进行分析,量化人类活动对禾水河水沙变化的贡献率。【结果】结果表明:(1)禾水河多年平均降雨量、径流量、输沙量分别为1622.75 mm/a、477.53亿m^(3)/a、26.65万t/a。近40 a降雨量、径流量年际变化稳定,汛期输沙量年际变化大,极值比27.37;(2)禾水河水沙年内分配不均。降雨量呈双峰形,第一次达到峰值的时间为6月,其次为8月;径流量与输沙量变化趋势一致,呈单峰形主要集中在汛期4—6月,分别占全年的45.31%、64.76%;(3)年降雨量和径流量均无显著变化趋势和突变;年输沙量呈显著下降趋势,在2006年发生突变,经贡献率分析,与水库建设和水土保持治理工程具有相关性,人类活动对禾水河水沙关系的贡献率为98%。【结论】人类活动是赣江中游禾水河年输沙量减少的主要因素,其中水土保持措施的减沙作用是缓慢的且有滞后现象,而功阁水库等水利工程的拦沙作用是显著且迅速的。

[Objective]To explore the driving factors of water and sediment change in Heshui River,a tributary of the left bank of the middle reaches of Ganjiang River,and to provide scientific basis for soil erosion control,land use and function adjustment in the middle reaches of Ganjiang River.[Methods]Mann-Kendall test,Pettitt test,cumulative anomaly method,double cumulative curve method and cumulative slope change rate method were used to analyze the rainfall,runoff and sediment discharge data of Shangshalan station from 1980 to 2019.The contribution rate of human activities to the change of water and sediment in Heshui River was quantified.[Results]The result showed that:(1)the average annual rainfall,runoff and sediment discharge of Heshui River were 1622.75 mm/a,477.53 billion m^(3)/a and 266500 t/a,respectively.In recent 40 years,the interannual variation of rainfall and runoff is stable,and the interannual variation of sediment transport in flood season is large,and the extreme value ratio is 27.37.(2)The annual distribution of water and sediment is uneven.The rainfall was bimodal,and the first peak was in June,followed by August.The trend of runoff and sediment discharge is consistent,and the single peak is mainly concentrated in the flood season from April to June,accounting for 45.31% and 64.76% of the year respectively.(3)There was no significant change trend and mutation in annual rainfall and runoff.The annual sediment discharge showed a significant downward trend,and the mutation occurred in 2006.The contribution rate analysis showed that it was related to the reservoir construction and soil and water conservation project.The contribution rate of human activities to the relationship between water and sediment was 98%.[Conclusion]Human activities are the main factors for the decrease of annual sediment discharge in Heshui River in the middle reaches of Ganjiang River.Among them,the sediment reduction effect of soil and water conservation measures is slow and lagging behind,while the sediment retention effect of water conservancy projects such as Gongge Reservoir is significant and rapid.