Legal Definitions - navigable water

The term navigable water refers to a body of water that is, or can be, used for commercial transportation and trade. Historically, in English common law, this primarily meant waters influenced by the ocean's tides. However, in the United States, the definition expanded significantly to include any waterway that can serve as a practical route for commercial vessels, even if it is far inland and not affected by tides.

This concept is crucial because it determines the extent of the federal government's authority to regulate waterways. Under the Commerce Clause of the U.S. Constitution, Congress has broad power over "navigable waters of the United States," which are those waterways that alone, or in combination with other waters, form a continuous highway for commerce with other states or foreign countries. This federal oversight allows for regulation of navigation, environmental protection, infrastructure development (like dams and bridges), and other activities impacting interstate and international trade.

Examples of Navigable Water:

• The Mississippi River:

  Scenario: Barges carrying agricultural products, petroleum, and other bulk goods regularly travel the Mississippi River from Minnesota down to the Gulf of Mexico, passing through multiple states.

  Explanation: The Mississippi River is a quintessential example of navigable water because it serves as a vital "highway for commerce" connecting numerous states and ultimately international markets. Its capacity to support large-scale commercial shipping means it falls under federal jurisdiction, allowing the government to regulate navigation, maintain the channel, and oversee environmental protection along its vast stretch.

• The Port of Los Angeles:

  Scenario: Large container ships from Asia and other parts of the world routinely enter the Port of Los Angeles to unload goods, which are then transported by rail and truck across the United States.

  Explanation: The waters within the Port of Los Angeles are considered navigable because they are actively used for international and interstate commerce, accommodating massive vessels and regular commercial traffic. The federal government exercises authority here to ensure safe passage, manage port operations, and enforce environmental regulations, recognizing its role as a critical gateway for global trade.

• A section of the Intracoastal Waterway in Florida:

  Scenario: A segment of the Intracoastal Waterway, a man-made channel along Florida's coast, is regularly used by commercial fishing boats, tour operators, and barges transporting construction materials between coastal towns and connecting to larger shipping lanes.

  Explanation: Even though parts of the Intracoastal Waterway are artificial, they are considered navigable water because they facilitate commercial transportation and connect to a larger system that supports interstate commerce. The consistent use by various commercial vessels for trade and travel means this waterway is subject to federal oversight for navigation, maintenance, and safety regulations.