Navigation Channels - Our Underwater Highways
Level 1

Major Ports and Waterways in the United States
Where are You?

The inland waterways navigation channels have been called our nation's underwater highways. Ships, boats and barges travel on the inland waterways, carrying products to and from ports around the world. The map above shows the location of the major inland waterways and coastal ports in the continental United States.

Instead of road maps, those who sail ships and boats on waterways use nautical charts. Nautical charts show the channels and a lot of other information about the area. Some of the other information on nautical charts are things like the depth of the channel, the location of ports, the location and height of bridges over the water, and the location of buoys and other channel markers. People depend on the chart information for the safety of their vessels and cargo.

If sands fill the channels, ships cannot safely pass.

Water carries sand and soil, as well as other floating material, like logs, along with it as it flows toward the ocean. Where the water slows down, the sand and soil drop to the bottom of the river channel. When the sand and soil drop to the bottom, they are called sediments.