Three Dimensional Downstream Scour Analysis After Levee Overtopping

Abstract

Three dimensional experiments are conducted to analyze the downstream scour dimensions after levee overtopping. For elucidating the difference of scour dimension under various hydraulic (overtopping flow height at the levee top, d bank ) and geometric parameters (levee height, h bank , overtopping flow width along the levee, W bank ), 3D scour profiles are investigated. From the analysis, it has been observed that at equilibrium conditions, for the same d bank cases scour depth (S d ) is higher for greater h bank (10cm) compared with lower levee height (6cm). In contrast, scour length (S l ) is longer in case of lower h bank compared to higher h bank for same d bank . The stronger hydraulic jump that took place in case of smaller levee height cases appears to play a significant role in developing greater scour length along with shorter scour depth. Three separate equations for S d , S l and S w (scour width) have been proposed from multiple regression analysis. These results can be useful for the study of levee design.