基于RS技术的北江下游河道岸滩演变分析

An Analysis on the Evolution of the River Course at Lower Reaches of the Beijiang by Remote Sensing Technique

以1975～2001年共7个时相的遥感影像作为数据源，在GIS支持下采用动态分析方法，对比各个时期北江下游河道岸滩形态及位置变化，结合河道的地质、地貌、水文泥沙、整治工程等信息，分析洲滩消长的原因，获取河道横向演变特性，预测岸滩变化趋势以及整治工程效果。对比该时段内北江下游河道纵向演变情况，得出河道的纵向变形影响横向变形，总体变化两者成反比关系，河势向着稳定的趋势发展。

Environment of river course is changed frequently due to nature and human activities, compared with traditional means; the remote sensing-based study on lateral fluvial processes has its advantages of macroscopic, dynamic, intuitionist and systematic features. In this paper, four-temporal remote sensing data from 1988 to 2001 are used for dynamic analysis in support of GIS technology, and the patterns and positions of bank-line and beach in different periods at the lower reaches of the Beijiang are compared. In combination with the information from Geology, Geomorphology, Hydrology, and engineering, the lateral fluvial processes are studied. The results show that the river regime has changed significantly since 1990s, which is characterized by the shift of the main stream and the disappearance of the small sandbars, and the time of these changes matches with the periods of sand dredging and waterway renovation. Compared with longitudinal evolution at the lower stream of the Beijiang during this period, the results show that the longitudinal deformation affects the lateral deformation of the watercourse and they have negative co-relationship. The development of the river regime tends to be stable.