人类活动影响下海南岛万泉河下游年最高水位阶段性演变研究OA

The human intervention makes the changes of river flood level deviate from the natural evolution process,which has a profound impact on flood control and navigation in the basin.To investigate the evolution trend and mechanism of flood level in the lower Wanquan River of Hainan Island in recent years,based on the highest water level data at the Jiaji station,combined with the dataset of water discharge and cross-sectional morphology,the evolution trend of annual highest water level was elucidated,and the influence of human activities was further identified.The results show that the evolution of flood level in the lower Wanquan River can be divided into two stages:steady fluctuation period(1980-2002)and rapid decrease period(2003-2020).During the rapid decrease period,the annual highest water level decreases by about 1.81 m,or 23%.Human activities(e.g.reservoir construction)are the main driving force for the significant decrease of the annual highest water level.Among them,the impact of reducing effect of reservoirs for the flood peak on the annual highest water level accounted for 41%,and the impact of the riverbed downcutting caused by the sediment trapping effect of reservoirs accounted for 51%.