Rivers and Groundwater Systems
Earth is often called the "Water Planet," and rightly so—it is about three-fourths water. At first glance it probably seems that we have plenty of water to go around. We do have plenty of water, but the problem is that most of it—97% of it, in fact—is salt water in the oceans that we cannot drink. The remaining 3% is called freshwater. Two common sources of freshwater are the focus of this unit.
This unit focuses on water in rivers at Earth's surface and water that is beneath the surface, called groundwater. You will learn about how rivers form and why they sometimes flood. You will also learn about where groundwater comes from, how it is used, and how humans impact the quality of groundwater.
