Which federal agency in the United States primarily oversees navigable waters?

The U.S. Army Corps of Engineers is primarily responsible for the oversight and management of navigable waters in the United States. This agency plays a critical role in maintaining the nation's waterway infrastructure, which includes the construction and maintenance of navigation channels, locks, and dams. They also regulate activities in navigable waters under the authority of the Clean Water Act and other legislation.

The Corps is involved in ensuring safe navigation, managing flood control projects, and preserving water quality. Their expertise in managing water resources relates directly to the maintenance and development of water pathways used for commercial and recreational purposes. Their comprehensive approach to waterways management also includes permitting processes for projects like docks, marinas, and other structures that could impact navigable waters.

In contrast, the other federal agencies listed have distinct areas of focus. For instance, the Environmental Protection Agency mainly deals with environmental regulation and protection, rather than directly regulating navigable waters. The National Oceanic and Atmospheric Administration focuses on ocean and atmospheric conditions and forecasting, while the Federal Bureau of Land Management manages public lands, which does not primarily include navigable waters. Thus, the U.S. Army Corps of Engineers is the correct choice for the oversight of navigable waters.