Heo Joon, Duc Trinh Anh, Cho Hyung-Sik, Choi Sung-Uk
School of Civil & Environmental Engineering, Yonsei University, 139 Shinchon-dong, Seodaemun-gu, Seoul, 120-749, Korea.
Environ Monit Assess. 2009 May;152(1-4):155-65. doi: 10.1007/s10661-008-0304-8. Epub 2008 May 29.
This study focused on the prediction of a 22 km meandering channel migration of the Sabine River between the states of Texas and Louisiana. The meander characteristics of 12 bends, identified from seven orthophotos taken between 1974 and 2004, were acquired in a GIS environment. Based on that earlier years' data acquisition, channel prediction was performed for the two years 1996 and 2004 using least squares estimation and linear extrapolations, yielding a satisfactory agreement with the observations (the median predicted and observed migration rates were 3.1 and 3.6 [m/year], respectively). The best-predicted migration rate was found to be associated with the longest orthophoto-recorded interval. The study confirmed that channel migration is strongly correlated with bend curvature and that the maximum migration rate of the bend corresponded to a radius of curvature [bend radius (R(C))/channel width (W(C))] of 2.5. In tight bends of a smaller radius of curvature than 1.6, secondary flow scouring near the bend apex increases bend curvature. The stability index of the dimensionless bend radius was determined to be 2.45. Overall, this study proves the effectiveness of least squares estimation with historical orthophotography for characterization of meandering channel migration.
本研究聚焦于预测德克萨斯州和路易斯安那州之间萨宾河一条22公里蜿蜒河道的迁移情况。从1974年至2004年间拍摄的七张正射影像中识别出12个河湾的河湾特征，并在地理信息系统（GIS）环境中获取这些特征。基于早年的数据采集，利用最小二乘法估计和线性外推法对1996年和2004年这两年进行河道预测，预测结果与观测结果吻合良好（预测和观测的迁移率中位数分别为3.1和3.6 [米/年]）。发现最佳预测迁移率与正射影像记录的最长时间间隔相关。该研究证实，河道迁移与河湾曲率密切相关，且河湾的最大迁移率对应于曲率半径[河湾半径（R(C)）/河道宽度（W(C)）]为2.5的情况。在曲率半径小于1.6的急弯处，弯顶附近的二次流冲刷会增加河湾曲率。无量纲弯半径的稳定性指数确定为2.45。总体而言，本研究证明了利用历史正射影像进行最小二乘法估计以表征蜿蜒河道迁移的有效性。
