Li Chao-Yue, Fang Hai-Yan
Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China.
Ying Yong Sheng Tai Xue Bao. 2020 Feb;31(2):590-598. doi: 10.13287/j.1001-9332.202002.011.
The variations of runoff and sediment flux are important factors influencing the socioeconomic development of Thailand. Based on the dataset of runoff and sediment flux during 1980-2014 at the Ubon hydrological station in the lower Mun River, a tributary of the Mekong River, the temporal variations of runoff and sediment flux were analyzed with the linear regression method, Mann-Kendall test, and wavelet transform method. The driving forces for the variations of runoff and sediment flux were discussed. The results showed that annual runoff in the Mun River basin increased slightly, while the sediment flux presented a decreasing trend. The changes of sediment flux and runoff were consistent before 2000. However, the sediment flux significantly decreased after 2000. During the study period, both the runoff and sediment flux during the flood seasons showed decrease trend. The abrupt change points of runoff and sediment flux did not occur in the same year, which were in 1999, 2006 and 2011 for runoff and in 1986, 1999 and 2011 for sediment, respectively. The main cycles of runoff amount were 14, 8 and 4 years, respectively, while those of sediment flux were 32, 12, 9 and 4 years, respectively. Except for the 32-year cycle of sediment flux, the main cycles of runoff and sediment flux were almost similar and both were mainly related to the Southern Oscillation, polar movement, sunspot activity, and other factors. There was a significant correlation between monthly runoff and sediment flux. Sea-air interaction and human activity were important factors influencing runoff and sediment flux in the Mun River basin. El Nino and La Nina were closely related to rainfall which in turn affected the runoff and sediment flux in the basin. Since 2000, the construction area increased and the forest area decreased, which increased the runoff in the basin, while the reservoirs and other engineering measures reduced the runoff and sediment flux, and thus offset the impact of decreased forest lands on sediment flux.
径流和输沙量的变化是影响泰国社会经济发展的重要因素。基于湄公河支流蒙河下游乌汶水文站1980 - 2014年径流和输沙量数据集，采用线性回归法、曼-肯德尔检验法和小波变换法分析了径流和输沙量的时间变化特征，并探讨了径流和输沙量变化的驱动因素。结果表明，蒙河流域年径流量略有增加，而输沙量呈下降趋势。2000年前输沙量和径流量的变化趋势一致，但2000年后输沙量显著下降。研究期间，汛期径流和输沙量均呈下降趋势。径流和输沙量的突变点不在同一年，径流突变点分别为1999年、2006年和2011年，输沙量突变点分别为1986年、1999年和2011年。径流量的主要周期分别为14年、8年和4年，输沙量的主要周期分别为32年、12年、9年和4年。除输沙量的32年周期外，径流量和输沙量的主要周期基本相似，且均主要与南方涛动、极地运动、太阳黑子活动等因素有关。月径流量与输沙量之间存在显著相关性。海气相互作用和人类活动是影响蒙河流域径流和输沙量的重要因素。厄尔尼诺和拉尼娜现象与降雨密切相关，进而影响流域内的径流和输沙量。2000年以来，建设用地增加，森林面积减少，导致流域内径流量增加，而水库等工程措施减少了径流和输沙量，从而抵消了林地减少对输沙量的影响。
