长江芜湖段疏浚砂利用实践与思考

Utilization of Dredging Sand in the Wuhu Reach of Yangtze River:Reflections and Practices

近年来,三峡水库出库泥沙量大幅减少,长江中下游河道水流挟沙力长期处于非饱和状态,相同流速下会加剧河床及河岸原堆积性或沉积性泥沙被水流冲起、带走,造成河床冲刷、河岸崩塌,影响防洪安全、河势稳定和水生态安全,目前长江安徽段已处于无砂可采状态。对近20 a长江铜陵、黑沙洲、芜裕3个河段的河床冲淤、河势变化以及重点崩岸区、重要港区、航道局部河势变化进行了分析,并研究了河道整治、航道整治、防洪工程加固、崩岸区治理等疏浚砂利用需求,结合维护河势稳定、航道通畅的总体目标,提出了疏浚砂不上岸利用,取之河道、用之河道的总体原则,以及维护河道水沙平衡、河势稳定和通航安全的具体利用思路。

In recent years,the sediment discharge from the Three Gorges Reservoir has decreased significantly,causing the flow of the middle and lower reaches of the Yangtze River to remain consistently unsaturated with sediment,which exacerbates the scouring of riverbeds and banks by causing deposited sediments to be washed away at the same flow rate.This phenomenon adversely impacts flood control safety,river stability,and water ecological safety.Currently,there is no sediment available for dredging in the Anhui reach of the Yangtze River.We analyzed the changes in riverbed erosion and siltation,channel transformation,and certain critical sections including bank collapse zones,important port areas,and navigational channels of Tongling,Heishazhou,and Wuyu segments of the Yangtze River in the past two decades.We further investigated the demand for dredging sand utilization in the regulation of waterways,navigational channels,flood control works,and bank erosion controls.Based on the overall target of ensuring stable river regime and navigational channels,we propose the principle of"not depositing dredged sediment on the bank,utilizing it from the river,and returning it to the river",as well as specific strategies to maintain the balance of water and sediment in the river,ensure river stability,and guarantee navigational safety.