gen-define-watershed-and-drainage-basins-and-give-one-short-work-e540

Define watershed and drainage basins and give one short worked example.

# Watershed and Drainage Basin ## Definitions **Watershed (or Divide)**: A ridge or elevated boundary that separates water flowing into different drainage basins. Water falling on opposite sides of a watershed flows into different river systems. **Drainage Basin (or Catchment Area)**: The entire land area that collects precipitation and drains it into a common outlet (river, lake, or ocean). It includes all tributaries and is bounded by watersheds. ## Worked Example **The Mississippi River Drainage Basin** - **Area**: Approximately 3.2 million km² - **Watershed boundaries**: - West: Rocky Mountains (Continental Divide) - East: Appalachian Mountains - North: Smaller divides near the Canadian border - South: Gulf of Mexico (outlet) **How it works**: - Rain falling in Pittsburgh, PA flows east to the Atlantic via the Ohio River → Mississippi River → Gulf of Mexico - Rain falling just 50 km west of Pittsburgh crosses the watershed and flows west to the same Mississippi system - Rain falling on the *western* side of the Rockies crosses the Continental Divide and flows to the Pacific Ocean instead **Result**: All water within this basin eventually drains to a single point (the Gulf of Mexico), while watersheds prevent mixing with adjacent basins (like the Rio Grande or Columbia River basins).