关键词: 弯曲河流, 崩岸, 有效流量, BSTEM, 黑河下游, 若尔盖高原

Abstract: Bank erosion and collapse play an important role on sediment transport in alluvial channels and lateral migration of meandering rivers. A combination method of field measurement, discharge frequency analysis, and numerical simulation (BSTEM), based on the prototype data of bank profiles, is used to study bank failure process and bank toe erosion and collapse in a Ω-shaped bend of the lower Black on the Zoige Plateau under constant and variable discharges. The results show that under constant discharges, bank erosion rate and retreat width are increased with discharge; while under variable discharges, both are nearly the same as those under the constant discharges with the same averages and are increased with the discharge average, indicating that the bank erosion rate and retreat width are independent of the shape, peak discharge, or dispersion of hydrographs. This means that bank erosion is affected by the magnitude of discharge and its frequency, and the erosion rate of bank toe and the bank retreat width are mainly controlled by average discharge, rather than the shape of hydrograph or peak discharge.

Key words: meandering river, bank failure, effective discharge, BSTEM, lower Black River, Zoige Plateau