FHWA HEC-18 (Fifth Edition)

Anyone involved in Bridge Scour Analysis must be completely familiar with the FHWA Bridge Scour guidance.
This circular documents the equations used in the FHWA Hydraulic Toolbox and guidance for using them.
Evaluating Scour at Bridges, Fifth Edition

FHWA 2D Hydraulic Bridge Modeling

Federal Highway published a document with some guidance and best practices for 2D hydraulic bridge modeling. 
Two-dimensional Hydraulic Modeling for Highways in the River Environment Reference Document

This document includes a lot of useful modeling content, but it is not up to date on HEC-RAS' capabilities.
An updated version of the HEC-RAS entry for Table 2.2 is included below: