The USACE has released a manual titled: "Standards and Procedures for Referencing Project Elevation Grades to Nationwide Vertical Datums", (EM 1110-2-6056).

This document, largely the result of the misconceptions of vertical datum’s revealed by levee failures in New Orleans due to Hurricane Katrina, addresses vertical datum use
not only for coastal projects, by also inland navigation and flood control. The entire document can be found at:

http://140.194.76.129/publications/eng-manuals/

Scroll down the list until you find "EM 1110-2-6056".