Earth’s surface is constantly changing, shaped by powerful natural forces that sculpt the landscapes we see today. Topography is the arrangement of a particular region’s natural and artificial physical features-in simpler terms, it is the shape of the land.  Words like flat, sloping, hilly, or mountainous might all describe the topography of a particular area.

Topographic maps include an area’s elevation, relief, and landform.  The topography of a specific area is often characterized by its elevation, which refers to the height at a point on Earth’s surface above sea level. For example, Denver, Colorado, is called “Mile High City” because it sits about one mile above sea level. Relief is the difference in elevation between the highest and lowest points of an area.  A prairie has low relief because it is mostly flat, while the Grand Canyon has high relief because there is a large difference between the canyon floor and the rim.

Moving from measurements to features, we encounter landforms, which are the natural features of Earth’s surface. Hills, valleys, mountains, and plateaus are all examples of landforms. A large area composed mostly of a single type of landform is called a landform region.

Among the most common landforms are plains, which are broad areas of nearly flat or gently rolling land with low relief. Because of their flat terrain and fertile soil, plains are often important agricultural regions. A coastal plain lies along a seacoast and typically has low elevation and low relief, as seen in the Atlantic Coastal Plain of the eastern United States. In contrast, an interior plain is located farther inland. Although it also has low relief, its elevation may vary more, as in the Great Plains of the central United States.

In contrast to plains, mountains are landforms with high elevation and high relief. This means they rise high above sea level and have steep slopes with large differences in height between valleys and peaks. Mountains rarely stand alone. Instead, they usually form groups called mountain ranges, which are long chains of mountains that share similar shapes, structures, and ages. Several related mountain ranges in the same region form a mountain system, and when multiple mountain systems connect across very large distances, they create a mountain belt.  Mountains play an important role in Earth’s systems. They influence the climate by blocking winds and creating wet areas on one side and dry rain-shadow regions on the other. Many rivers begin in mountains as snow and glaciers melt and flow downhill. As elevation increases, temperatures decrease, creating different climates and ecosystems at different heights. Mountains are also important to people because they provide fresh water, natural resources, and recreation opportunities.

Finally, plateaus combine characteristics of both plains and mountains. Like mountains, plateaus have high elevation and rise above the surrounding land. However, like plains, they have relatively flat surfaces on top. The Colorado Plateau is an example of a high, level landform that rises above the surrounding landscape. Plateaus are important because they often contain valuable natural resources such as minerals and fossil fuels. They also support unique plants and animals adapted to higher elevations.

Review:

1. What does a topographic map show?
2. Explain the difference between a coastal plain and an interior plain.
3. Compare mountains to plateaus.