近50年海南三大河入海水沙通量特征及变化

Characteristics and variations of water and sediment fluxes into the sea of the top three rivers of Hainan in recent 50 years

利用海南岛南渡江、昌化江、万泉河1957-1987年和2006-2008年的河口水文资料,分析了这三条河流不同月份、不同季节入海径流量和输沙量的分布特征和不同年份的年际变化特征。结果表明,海南三大河入海水、沙通量在夏、秋台风季节(7-10月)最大,峰值多出现在9月或10月,三条河流水沙通量总体呈现洪水多沙、枯水少沙的特点,南渡江入海径流最为丰沛,而昌化江为输沙最强河流。近50年来,海南三大河入海水沙通量总体呈下降趋势,20世纪80年代以前水沙通量围绕平均值波动较大,20世纪80年代以后明显偏低;流域降水变化可能是促使三条河流入海径流量变化的主要原因,而输沙量的变化除了流域降水变化的因素以外,流域坡降、下垫面性质以及人类活动的影响也起到了较大的作用。

Based on the hydrological data at the estuaries of Nandu River,Changhua River and Wanquan River from 1957 to 1987 and from 2006 to 2008,this paper analyzed monthly,seasonal and annual variations in terms of runoff and sediment discharges of three rivers into the sea.The results showed that typhoon season(July-October) was revealed to be the period for the peaks of water and sediment fluxes,particularly during the period of September or October.Three rivers also featured more sediments with floods and less sediment with low flow.Nandu River was of the largest water discharge and Changhua River had the strongest sediment transport.Water and sediment fluxes were found to show a decrease overall in recent 50 years.Before 1980s,water and sediment fluxes fluctuated greatly around the average,but the deviation reduced since 1980s.The change of runoff discharges might mainly be related to the precipitation of the fluvial basins.Meanwhile,precipitation,basin slope,underlaying surface properties and human activities were considered to be the factors affecting sediment discharges.