Unit 1: Fresh Water: Scarcity or Surfeit?



Water is often called the “Elixir of Life.” We refer to Earth as the “Blue Planet” because of its abundance of liquid water; indeed, NASA’s search for life on other planets starts with the search for water. While its importance for sustaining life is perhaps common knowledge, the extent to which we depend on water in every aspect of our everyday lives and activities is less obvious. In this course, we will explore these facets of water’s impact on human society. We begin with an overview and discussion of the underpinnings of water use, occurrence, and movement. We then explore the many and profound consequences of human manipulation of water; the ability to reroute, store, and transport water is one of the very things that has allowed human civilizations to thrive, yet has also led directly to a complex and broad-ranging relationship with this most essential of substances. Water pervades almost every aspect of our existence, including food production; the manufacture of goods and development of new technologies; transportation and energy generation; human health via its use for sanitation, the conveyance of waste, and control on the distribution of water-borne diseases; and the sustenance of ecosystems on which we often depend but do not realize. Not only is water needed for you to be here and to produce your breakfast this morning, but the computer you are using to read this course’s modules, the electricity needed to turn on your computer, the steel and fuel needed to transport you to/from school all required even more water!

Through its importance in these arenas, it is perhaps unsurprising that water allocation and policy lie at the heart of economic and political tensions between communities, states, and nations. As populations in many water-stressed areas continue to grow, and in the face of climate changes that affect where and when water may be available in the future, these challenges continue to mount.

We begin this course by providing an outline of water resources on a global basis—where resources are abundant or limited and why. We first ask questions regarding the "value" of water and consider whether having access to fresh (uncontaminated) water for drinking and other household uses is a fundamental right as opposed to water being a commodity subject to profit-taking. In other words is water a resource that is subject to privatizations and price fluctuations, or should water be provided by benevolent governments at reasonable cost? In addition, we are concerned with projected population growth, its regional distribution, and resulting demands for water in the future. This helps us appreciate the two-way relationship between water and human society: how water availability and quality affect economic opportunities and human well-being, and how human activity affects water resources.

A major consideration is why some regions have a surplus of water and others have less than necessary to support local populations in various activities. In order to understand this, we need to examine the operation of Earth's climate system in some detail: the roles of global wind systems, proximity to an ocean, and topographic features (especially mountain belts) in determining patterns of rainfall, a first-order control on water availability. This involves discussion of the global "hydrologic cycle" that reflects the cycling of water from ocean to atmosphere to land and its ultimate return to the sea. We also outline some of the important properties of water that determine its behavior in the climate system, flowing water, and sustaining life.


Unit Goals

Upon completion of Unit 1 students will be able to:

  • Describe the two-way relationship between water resources and human society
  • Explain the distribution and dynamics of water at the surface and in the subsurface of the Earth
  • Interpret graphical representations of scientific data
  • Identify strategies and best practices to decrease water stress and increase water quality
  • Communicate scientific information in terms that can be understood by the general public
  • Predict how availability of and demand for water resources is expected to change over the next 50 years

Unit Objectives

In order to reach these goals, the instructors have established the following learning objectives for student learning. In working through the modules within Unit 1 students will be able to:

  • List the primary reasons that most population centers developed near major rivers or other surface water bodies.
  • Provide examples of consumptive and non-consumptive, and direct and indirect water uses.
  • Compare the amounts used by the various end-users of water, both in the U.S. and globally.
  • Identify regions of critical water stress at present and those anticipated 20 and 40 years into the future.
  • Identify possible solutions to anticipated water shortages.
  • Discuss issues surrounding the debate about public access to (clean) fresh water.
  • Identify the unique physical properties of water that contribute to its fundamental role in driving Earth Systems.
  • Quantitatively compare fluxes of water in the hydrologic cycle.
  • Assess the relationship between precipitation, topography, and location in the U.S. and globally.