For the InstructorThese student materials complement the Water Science and Society Instructor Materials. If you would like your students to have access to the student materials, we suggest you either point them at the Student Version which omits the framing pages with information designed for faculty (and this box). Or you can download these pages in several formats that you can include in your course website or local Learning Managment System. Learn more about using, modifying, and sharing InTeGrate teaching materials.
Driving Forces for Groundwater Flow
The driving forces that control groundwater flow are a bit more complicated than those more familiar to us for rivers and streams we can see at the land surface. As you learned in Module 3, surface water flows downhill due to gravity, and the flow direction is defined simply by the topography. The reason that water flows downhill, of course, is that gravity is a form of potential energy – and the water, or anything that falls or rolls downward – flows in response to that difference, from high to low potential energy.
In contrast to surface water, groundwater is separated from the atmosphere, and as a result it may also be under considerable pressure. As a result, the potential energy that drives groundwater movement includes both pressure and gravity. In this section you will learn about these driving forces, how we define them, and how they translate to the direction and rate of groundwater movement in the subsurface.