Wednesday Mini-Lesson: How Geography impacts human settlement, pt 1-2

Bodies of Water

How do the bodies of water in the United States affect people’s lives?

Oceans, lakes, and rivers have helped make the United States prosperous. Oceans link the country to other countries for trade. The United States is bordered by the Atlantic Ocean to the east, and the warm waters of the Gulf of Mexico in the southeast. The Pacific Ocean borders the western coast. Included in the land area of the United States are numerous freshwater lakes and rivers. Many of the rivers in the United States are navigable, or wide and deep enough to allow the passage of ships. The abundant supply of freshwater provides power for homes and industries.

The Great Lakes

The term Great Lakes refers to a cluster of five huge lakes located in the American Midwest and central Canada. They form the largest group of freshwater lakes in the world. The lakes are Lake Superior, Lake Michigan, Lake Huron, Lake Erie, and Lake Ontario from west to east. Water flows west to east from one lake to the next and then into the St. Lawrence River.

The St. Lawrence River carries the water eastward for 750 miles (1,207 km) to the Atlantic Ocean. During the 1950s, the United States and Canada worked together to build canals and gated passageways called locks between the Great Lakes and into the St. Lawrence River. The final passageway, the St. Lawrence Seaway, extends 2,340 miles (3,766 km) from Lake Superior to the Atlantic Ocean. It connects the Midwest to seaports all over the world, making it faster and easier for businesses in the Midwest to ship their products to buyers worldwide.

The Mississippi River System

The “Mighty Mississippi” is one of the longest rivers in North America. From its source in Minnesota, the Mississippi River winds its way southward for 2,350 miles (3,782 km) to the Gulf of Mexico. Tributaries such as the Missouri and Ohio Rivers feed into the Mississippi.

The Mississippi River has affected the settlement patterns, the economy, and the lifestyles of countless Americans. People have used the river for transportation for hundreds of years. Ships and steamboats filled with passengers and cargo can follow the wide river and its tributaries for thousands of miles, making it one of the world’s busiest waterways.

In the past, the Mississippi would often flood its banks, dumping millions of tons of water and sediment onto the land. The sediment enriched the soil, but the floods also destroyed homes and washed away entire fields of crops. The government built levees—embankments to control the flooding and reduce the damage to homes and crops. Unfortunately, levees also block the sediment that used to replenish farm fields.

Western Lakes and Rivers

The United States west of the Mississippi River is much drier than the eastern part of the country. But thousands of years ago, the climate was wetter. A huge, freshwater lake covered many of the basins that are located in what are now Utah, Idaho, and Nevada.

One of the few lakes that remain is Utah’s Great Salt Lake, the largest salt lake in the Americas. Two other important lakes in the region are Lake Tahoe and Lake Mead. Lake Tahoe sits high in the Sierra Nevada. Lake Mead is a human-made lake formed when Hoover Dam was built on the Colorado River. Both lakes are used for boating and other water recreation.

The Colorado River is one of the major rivers of the region. It begins along the western slope of the Rocky Mountains and twists its way south and west to the Gulf of California. To the north, the Columbia River flows from the Rocky Mountains to the Pacific Ocean. The river has been dammed in several places to provide hydroelectric power. The dams also control floods and provide water for urban and rural areas. The Snake and Willamette Rivers feed into the Columbia River.

All these rivers flow west. But some of the rivers in the region flow east toward the Gulf of Mexico. The Continental Divide, the high ridge of the Rocky Mountains, separates these two sets of rivers. The eastward-flowing rivers include the Missouri, the Platte, the Kansas, the Arkansas, and the Rio Grande.