canals

A canal is an artificial waterway created to connect bodies of water, provide a navigable route for ships and boats, or supply water for irrigation, drainage, and flood control. Canals are engineered to control depth, width, channel slope, and flow, and they differ from natural rivers by their deliberate construction and management.

Canals serve multiple purposes, most notably navigation and irrigation. Navigation canals enable inland trade by linking seas or large river systems with interior regions, shortening journeys and reducing travel time. They may be used for commercial shipping, passenger transport, or as components of irrigation networks in arid areas. Some canals are sea level and use no locks, while many inland canals rely on locks to raise or lower vessels between different water levels.

Historically, large-scale canal building has played a major role in economic development. Notable examples include the Grand Canal in China, the Erie Canal in the United States, and various European networks that facilitated trade and movement before the prominence of rail and road transport. The Panama Canal and the Suez Canal are among the most consequential modern waterway links, with the former using locks to pass between ocean basins and the latter functioning largely as a sea-level route.

Canals are usually composed of a team of hydraulic structures and features, such as locks, gates, culverts, aqueducts, and dredged channels. Towpaths allowed draft animals to move boats, and later mechanical propulsion and towing systems reduced reliance on animal traction. Maintenance is ongoing and often overseen by national or regional authorities, including dredging, water level control, and structural repairs.

Economic and environmental impacts vary; canals support commerce, agriculture, and tourism, but can affect habitats, water quality, and local ecosystems. Modern improvements aim to accommodate larger vessels and optimize water management while mitigating ecological effects.