Gregg Gallagher, age 14, of Monroe, La., for his question:
WHEN WAS THE FIRST NAVIGABLE CANAL BUILT?
A navigable canal is a waterway constructed for the purpose of navigation. There are generally two kinds: ship canals, which are deep enough to accommodate ocean going vessels, and shallower canals used mainly by barges. The first one was built about 4000 B.C.
Ancient canals served as means of navigation and communication for the Assyrians, Egyptians, Hindus and Chinese.
The remains of a canal near Mandali, Iraq, date from about 4000 B.C.
The Grand Canal of China, connecting Tianjin City (Tientsin) and Hangzhou (Hangchow), was begun in the 6th century B.C. and completed in A.D. 1327. It is still in use today.
The canal lock was invented in Europe in the late 15th century.
Several important French canals were built in the 17th century, including the Briere, Orleans and Languedoc canals.
During the 18th century in Russia a great system of canals connecting Saint Petersburg (now Leningrad) with the Caspian Sea was built. The Gota Canal, a 240 mile long system of lakes rivers and canals, about 54 miles of which can accommodate oceangoing ships, connects Stockholm and Goteborg and was completed in 1832. The Ludwig Canal, joining the Danube with the Main and Rhine rivers and totaling about 110 miles, was built in 1832.
Perhaps the world's two most famous canals are the Suez and the Panama. The Suez Canal, opened in 1869, links the Mediterranean and the Red Seas. The Panama Canal, first used in 1914, joins the Atlantic and Pacific oceans. The Suez Canal is about 100 miles long while the Panama Canal is about 50 miles long.
The first navigation canal in the United States was built around the rapids of the Connecticut River at South Hadley, Mass., in 1793. It had two levels connected by an incline, over which boats were transported in tanks filled with water and dragged by cables operated by water power.
The construction of the Erie Canal, started in 1817, marked the beginning of an era of canal building, which produced an aggregate of more than 4,500 miles of canals (mostly in the Middle Atlantic and Central states and was largely responsible for opening the American Midwest to settlement.
Many of the early canals are no longer in active service, having been superseded by railroads and by modern, enlarged waterways. These include the Mississippi River system, which is navigable for 1,837 miles and has 30 locks and dams; the Illinois Waterway, which links Lake Michigan with the Mississippi River; the 981 mile Ohio River waterway system, extending from Pittsburgh, Pa., to the Mississippi River; and the New York State Barge Canal System, a principal section of which connects Lake Erie with the Hudson River.
The intracoastal waterways along the Atlantic and Gulf coasts are an important part of the inland waterway system of the U.S., which totals more than 25,000 miles.
The Canadian canal system includes the Saint Lawrence River canals,