近50a来福建海坛海峡动力地貌演变过程

Dynamic geomorphologic evolution of the Haitan Strait,Fujian province,in the past 50 years

福建海坛海峡是闽江和浙闽沿岸流南下物质向兴化湾及福建中南部沿海输运的重要通道。本文运用GIS手段对海坛海峡近50a来的地形资料进行了分析研究,研究结果表明:1964—1975年,闽江流域性洪水导致海坛海峡表现为较强的淤积;1975—1990年受闽江上游水土保持和大量水库建设的影响,海峡经历了较强的冲刷过程,此后冲刷速率逐渐降低,以轻微冲刷为主;2007年以后由于大规模人工采砂影响,海坛海峡北部出现大范围侵蚀。2007年以前,闽江来沙量是海坛海峡地貌演变的主要控制因素,其流域洪水、采砂和水库修建等都对海峡内的地貌演变产生直接影响;而2007年以后,海峡内大范围的人为采砂活动和围填海工程逐渐成为影响其地貌演变的主要因素。

The Haitan Strait in Fujian province is an important channel for the southward transportation of material from the Minjiang River and the Zhejiang-Fujian Coastal Current to the Xinghua Bay and the south-central coast of Fujian.The topographic data of the Haitan Strait in the past 50 years was analyzed using GIS tools.The results indicate that strong siltation occurred in the Haitan Strait due to the influence of several catastrophic floods in the Minjiang River Basin during 1964~1975.The Haitan Strait experienced strong erosion during 1975~1990 which is caused by water and soil conservation and reservoir constructions in the Minjiang River Basin.After that,the erosion rate declined gradually and the strait maintained slight scouring.Large-scale artificial sand mining started since 2007 that caused severe erosion in the northern part of the Strait.Before 2007,sediment discharge from the Minjiang River was the main factor restricting the geomorphological evolution of the Haitan Strait.Flood,sand mining and reservoir construction had a direct impact on the geomorphologic evolution of the strait.However,after 2007,large-scale artificial sand mining activities and reclamation projects in the strait have gradually become the main factors to affect its geomorphologic evolution.