Study on Runoff Characteristics and Countermeasures of the Upper Reaches of Nanpanjiang River Under the Background of Drought in Southwest China

Abstract

Climate change can cause strong fluctuations in the hydrological series. From 2009 to 2013, the continuous drought in southwest China had a very adverse impact on local climate and hydrological elements. In this paper, Xiaolongtan Hydrological Station, an important hydrological observation station on the Nanpanjiang River basin in southwest China, was taken as the research object. Mann-Kendall method was used to analyze the trend and abrupt change of the long series of runoff from 1961 to 2018 in Xiaolongtan. On this basis, the contribution rate of climate change and human activities to the runoff change of Xiaolongtan Hydrological Station in Nanpanjiang was quantitatively analyzed by using the double mass curve method. The results show that :(1) the runoff of Nanpanjiang River basin decreased from 1961 to 2018, and abruptly changed in 1980. Human activities were the main driving factor for the annual runoff reduction of Nanpanjiang River basin, contributing 96.23% to runoff reduction, and precipitation contributed only 3.77% to runoff reduction. (2) The construction of Chaishitan Reservoir played a crucial role in the annual redistribution of water volume in the Nanpanjiang River basin, which greatly reduced the adverse impact of successive droughts on the surrounding areas of the Nanpanjiang River basin. The results of this study can alleviate the adverse effects of continuous drought on the Nanpanjiang River basin and provide an important reference for the rational allocation of water resources in the Nanpanjiang River basin under drought conditions.