Bulkhead construction brings a lot of federal regs, state regs, regional regs, etc, into the equation.
My guess is that if you're in the process of figuring out how to design it, you haven't gone for the permits yet. Check with the local office first, and work your way up. They usually specify certain design feature minimums, like how deep the pilings have to be driven and such.
Also, the ACE usually has to approve a bulkhead permit if it's in a coastal area or navigable (boat traffic) waterway. Typically you submit a package to them, they issue a permit number, they do a Section 10 review, and either issue an approval letter or deny it. If approved, then the local folks get involved.
Here are a couple links for other states, just to give a flavor. I see engineers stamps and signatures everywhere.
http://www.toh.li/content/bz/forms/bulkhead.html
http://www.scdhec.gov/environment/ocrm/notice/docs/PN062306/CAP062306_Bellamy.pdf