Burial Design Criteria for Tidal Flow Crossings

Design criteria for burial depths (for submarine pipelines, cables, diffusors, etc.) across tidal rivers, estuaries and inlets are examined. For the case of shallow, alluvial tidal rivers and estuaries, design computation based upon real-time records is suggested. Numerical hydrodynamic models may be used to fine the instantaneous flow depths and velocities. faculties corresponding tractive stresses can then be computed for peak velocities by assuming a logarithmic velocity distribution. For tidal inlets, additional considerations must be given to the effects of waves on sediment transport near the seaward end of the inlet. A relationship for predicting the maximum scour depth in a new inlet as a function of the spring tidal prism is proposed. For inlets that are to be modified, the expected change in the maximum depth due to a change in the tidal prism can be computed.