It's really quite easy, especially with the special panel clips which I invented and which are shown here. They are made out of mild steel in a process known as progressive die stamping. Then they could be plated to prevent rusting and corrosion. These clips are strong, practically indestructable and can be made in quantities quite cheaply.
In just a couple hours that stack of plywood panels and box of clips could yield dozens of 8'x8'x8' tall privacy cubicles for the flood evacuees to use. Families could group together and enjoy a modicum of privacy, rather than just bunking down in a large room full of people. Sick and injured evacuees would benefit from this small degree of privacy and the whole thing is very economical to create.
Furthermore, once the emergency has passed these panels and clips could be quickly disassembled and stored top be ready for the next time they are needed.