Most navigable waterways are within the jurisdiction of at least one regulatory agency. Any proposed structure that extends beyond the ordinary high water line or mean high water elevation will likely require authorization from one or more regulatory agency. Examples of over-water structures include Seawalls, rip-rap, marinas, docks, piers, and mooring piles. Regulation of these structures is often required from federal, state, and local agencies. The federal and state regulatory objectives often center on navigability issues, sovereign submerged land leases, and resource impacts (e.g. seagrass beds and oyster reefs).