Permanent work that changes a facility’s location, footprint, alignment or size, or affects natural or cultural resources, gets a deeper review, which is common for improved, alternate, relocation, code upgrade and mitigation projects. In alternate and alternative procedures projects, if you don’t repair or sell the old facility and it’s unsafe, you must secure it or demolish it, and coordinate with the historic and resource agencies.
For changes in size, location or alignment: design plans and any agency consultations. For alternate and alternative procedures projects that leave the original facility: documentation of coordination with SHPO/THPO, Fish and Wildlife, NMFS or the Corps of Engineers, and the agreed measures; or records showing the original facility was secured or demolished.
On alternate projects, the old site is still your responsibility. Coordination costs with historic or resource agencies there are generally yours unless directly tied to repairing disaster damage, and salvage income reduces the capped funding.