Based on the implementation of the 12.5 m deep-water channel regulation project (phase I) in the Changjiang river downstream of Nanjing,this paper focuses on the scouring issues of applied regulation structures,studies the regularity,main influence factors and mechanism of general scour as well as scouring around the submerged spur dike,and respectively deduces in line with the fundamental theory of river dynamics the semi-empirical and semi-theoretical formulas for calculation of scouring depth resulting from initial flow velocity and initial shear stress.Based on practical examples of scouring occurred around non-submerged spur dike and the results of numerical scouring modeling for submerged spur dike,these formulas are verified and calibrated with good effects,and they are not only applicable to the calculation of scouring depth around the non-submerged and submerged spur dikes,but also suitable for the calculation of scouring depth developed at longitudinal dike and revetment in view of the fundamental theory of river dynamics.This paper makes a systematic summary of the major study results related to the semi-empirical and semi-theoretical formulas for calculation of scouring depth.