From Marshwater, who inspected and certified Hurricane Creek Wetlands:

"One misconception is that there must be water on the surface to be a wetland.  Actually, a wetland can never have water on the surface and still be a jurisdictional wetland.  As long as the vegetation and soils criteria are met, the water table can be as deep as 12" below the ground surface."

Ronnie Dilbeck, PG
Marshwater