摘要
为研究近年闽江下游干流河床下切演变特征,探讨采砂对河道下切的影响,利用1999—2020年7个不同年份实测地形资料进行河床平面、剖面和冲淤量变化分析,并结合采砂资料测算采砂对河道下切的贡献占比。结果表明:1999—2020年闽江下游干流冲刷剧烈,84.18%的区域发生冲刷,总冲刷量约2.55亿m^(3),平均冲刷深度5.09 m,深泓线平均冲刷深度7.87 m;1999—2011年整体急剧冲刷,冲刷总量占1999—2020年冲刷总量的82.51%,2011—2020年冲刷相对缓和;除2014—2017年河床整体略淤积外,其余各时间段均整体冲刷;水口坝下[15,30]km河段下切最剧烈;采砂是导致河床下切的最主要原因,估算其对河床下切贡献值超过50%。研究成果揭示了近年来闽江下游干流河床下切变化过程、特征及趋势,并首次得出采砂对河床下切的定量影响,可为闽江下游干流河道演变及治理、采砂规划提供基础支撑,并供防洪、河道保护管理及涉河项目建设等参考。
[Objectives]In recent years,intense channel evolution in the lower reaches of Minjiang River has negatively impacted channel stability,flood control,water supply,and aquatic ecosystems,thereby constraining socio-economic development in riverside cities.The mainstream of the lower Minjiang River(from Shuikou Dam to Huai’an Diversion Outlet)has been a key sand mining area,with significant riverbed incision.However,previous studies have paid insufficient attention to this phenomenon.This study aims to thoroughly investigate the evolutionary processes and characteristics of riverbed incision in this reach and quantify the impact of sand mining on the riverbed incision.[Methods]Using measured topographic data from seven different years(1999-2020),the evolutionary characteristics of riverbed incision were analyzed in terms of planform changes,cross-sectional profiles,and scouring and deposition variations.Based on river sand mining data,the contribution ratio of sand mining to the riverbed incision was calculated.[Results](1)the mainstream of the lower Minjiang River experienced intense overall scouring from 1999 to 2020,with scouring erosion occurring across 84.18%of the channel area,resulting in a total scouring volume of approximately 255 million m^(3).The average incision depth was 5.09 m,while the thalweg exhibited an average incision of 7.87 m,with a maximum incision depth approaching 20 m.(2)The riverbed underwent rapid scouring before 2011,whereas the scouring rate significantly decelerated thereafter.The total scouring volume during 1999-2011 and the average thalweg incision accounted for 82.51%and 76.11%of the respective totals for 1999-2020.(3)Except for a slight overall deposition in the riverbed during 2014-2017,net scouring occurred in all other periods,with the highest mean annual incision rate observed between 2008 and 2011.(4)The most pronounced incision occurred in the 15-30 km reach downstream of Shuikou Dam,where the average incision depth reached 6.92 m during 1999-2020,and significant incision persisted there after 2011.(5)Sand mining was identified as the primary driver of riverbed incision,estimated to contribute over 50%to the riverbed incision.[Conclusions]The findings reveal the processes,characteristics,and trends of riverbed incision in the mainstream of the lower Minjiang River in recent years and identify the most severely incised reaches.For the first time,a quantitative assessment of the impact of sand mining on the riverbed incision is provided,and it is suggested that sand mining has been the dominant factor driving riverbed incision in the mainstream of the lower reaches of Minjiang River in recent years.These results provide fundamental support for channel evolution,river management and sand mining planning,and also offer valuable references for flood control,river channel protection,and river-related project development.
作者
夏厚兴
陈能志
付开雄
董维良
何承农
张晓
黄梅琼
XIA Hou-xing;CHEN Neng-zhi;FU Kai-xiong;DONG Wei-liang;HE Cheng-nong;ZHANG Xiao;HUANG Mei-qiong(Fujian Provincial Investigation,Design&Research Institute of Water Conservancy&Hydropower Co.,Ltd.,Fuzhou 350001,China;Fujian Key Laboratory of Hydrodynamics&Hydraulic Engineering,Fuzhou 350001,China)
出处
《长江科学院院报》
北大核心
2025年第11期25-32,共8页
Journal of Changjiang River Scientific Research Institute
基金
福建省水利科技项目(MSK201904)。
关键词
河床演变
河道下切
采砂
定量分析
闽江
riverbed evolution
riverbed incision
sand mining
quantitative analysis
Minjiang River
