基于水文变异诊断系统的珠江河口三角洲水沙情势演变分析

Analysis of the Evolution of Water and Sediment Situation in the Pearl River Estuary Delta Based on the Hydrological Variation Diagnosis System

摘要: 为解决单一或较少水文变异检验方法无法充分支持检验结果的可靠性的问题，本文基于10种水文变异检验方法构建水文变异诊断系统，对珠江河口三角洲马口、三水、博罗水文站1959~2019年的实测水沙序列进行综合性变异特征诊断，并对水沙情势变化的成因展开分析。结果表明，1990年以来，珠江河口输沙量较1990年前显著减少，其中马口、三水两站近十年的最大输沙量较多年平均值分别下降65.45%和65.53%。在水沙序列变异形式上，马口站主要为跳跃变异，三水站为趋势变异，而博罗站年径流序列变异特征不明显，年输沙序列为跳跃变异。水沙情势变化导致由三水站进入三角洲河网区的分流比增加约8.1%，分沙比增加约28.3%，进而引起珠江河口东四口门的分沙比增加。在水沙情势变化的成因方面，上游拦河筑坝、流域采砂、水土保持等人类活动是珠江河口水沙量变化的主要原因。

Abstract: In order to solve the problem that deficient hydrological variation test methods cannot fully support the reliability of the test results, this study forms a hydrological variation diagnosis system based on 10 hy-drologic variation test methods to provide a comprehensive analysis of the measured water and sediment series of Makou, Sanshui, and Boluo hydrological stations in the Pearl River estuary delta during 1959~2019 and to further explore the causes of the changes in the water and sediment situation. The re-sults show that the sediment load in the Pearl River estuary has decreased significantly since 1990. The maximum sediment load of Makou and Sanshui stations in the past ten years decreased by 65.45% and 65.53%, respectively, compared with the multi-year averages. In terms of the variation form of water and sediment series, Makou station mainly shows jump variability, and Sanshui station is biased to trend vari-ation, while the variability of runoff series of Boluo station is not characterized by obvious features, but its sediment series presents jump variability. The change of water and sediment situation leads to an in-crease of 8.1% and 28.3% in the proportion of water and sediment entering the delta area from Sanshui station, which subsequently increases the ratio of sediment distribution at the four river mouths on the east side of the Pearl River estuary. With regard to the triggering factors of the water and sediment situa-tion, human activities in the Pearl River Basin such as upstream damming, sand mining and soil and water conservation are the main reasons for the variation of the water and sediment situation.