Began by reviewing second exam. Key questions that will be repeated on
the final: Hadley cell and warm and cold fronts (the changes in weather
that you expect as a front passes through).
What exactly do we mean by groundwater?
The water beneath the land surface that is in rock. Review: most water on
Earth is salt water. Only about 3% of all water is freshwater. Most of this
freshwater is tied up in glaciers. Now, subsurface water is comprised
of (1) mostly groundwater and (2) a little bit of soil moisture above the
groundwater table. Groundwater can be either shallow or deep groundwater.
An outline of this information follows:
subsurface water:
This diagram shows how water percolates downward from the surface. Immediately
beneath the surface is the zone of aeration, which is not saturated, and
below that is the zone of saturation, where the rock is 100% water-saturated. The dividing line between the zones
of aeration and saturation is called the groundwater table.
How do you get water into rocks?
In a rock, there are spaces between grains called pores. The amount of porespace is called "porosity." To get water to flow through a rock, these pores must be connected. The
connectedness of pores is called "permeability." A rock that is both porous and permeable is called an aquifer. A rock that is impermeable is called an aquiclude.