Introduction
This old fashioned water pump is the only way to get water at Upper Chatanika State Recreation Area in Alaska. Back in the “good old days” this is how towns or houses accessed water. In the U.S., these pumps only remain at hunting cabins and some rural state and federal campgrounds (Alaska Department of Labor).
Up to this point we’ve covered the basics about Earth Science, the Scientific Method, and started covering Earth’s many systems. Our focus of the last three Modules (Geologic Time and Plate Tectonics, Rocks and Minerals, and Soils) has focused on the Lithosphere. In this Module, we’ll cover the Hydrosphere. As you will see, it’s really difficult to speak of one Earth System without speaking of the others because, as the concept of Environmental Unity states, all Earth Systems are connected, affecting and being affected by each other.
As you have probably surmised, the Hydrosphere is the Earth System that has to do with water. Hydro comes from the Greek word hỳdōr, which means water. Our hydrosphere is an important resource that has shaped and continues to shape the Earth's surface and the development of ecosystems. Water is one of those essential resources. It is absolutely necessary to life. As we learned in the Introduction and Principles module this resource is one that sets the carrying capacity of the Earth. Today, we currently use 50 – 75 percent of the freshwater on the planet with a current population of 7 billion. Our best estimates show that we only have enough fresh water to support about 9 billion people.
In this section, we will more closely exam the hydrologic cycle, looking at surface water (runoff), groundwater, and glaciers. Once we have an understanding of how these resources are formed, we will look specifically at how we use these resources on a global scale as well as here in Indiana. We’ll build on many of the concepts we cover here when we discuss Ecosystems, Rivers and Flooding, and Resources.