Admiralty courts used to only have jurisdiction over the sea as far as the tides ran up the rivers. Somehow that all changed. I think it first got extended to the Great Lakes because of action during the war of 1812. Then they took it up river and then covering all land drained by rivers and all wetlands. It was one way of getting Fed jurisdiction over state jurisdiction land. The Feds used to have only jurisdiction over forts, magazines and post offices inside states. This is why the Fed owns so little land in the first 13 states.