Stability shear stress and equilibrium cross-sectional geometry of sheltered tidal channels

摘要: This study relates tidal channel cross-sectional area (A) to peak spring discharge (Q) via a physical mechanism, namely the stability shear stress ( tau sub(S)) just necessary maintain zero gradient in net along-channel sediment transport. It is assumed that if bed ) greater than sub(S), erosion will occur, increasing A, and reducing similar (Q/A) super(2) back toward sub(S). If < sub(S) there be deposition, A survey of literature allows estimates Q at 242 sections 26 separate sheltered systems. Assuming single value characterizes entire length given channel, it predicted geometry follow relation Ah sub(R) super(1) super(/) super(6) Q. Along-channel regressions form super( beta give mean observed for 1.00 plus or minus 0.06, which consistent with this concept. Results indicate lower bound on (and an upper A) stable channels provided by critical sub(C)) capable initiating motion. Observed found vary among all systems as function range (R sub(sp)) according approximately 2.3 R sub(sp) super(0.79) sub(C). deviations from uniform along individual are associated variation direction maximum (i.e., flood-versus ebb-dominance).