| Only
a small percentage of Earth's water is actually available
for human use at any time. Seawater, ice, and water in
the atmosphere account for more than 99% of the water
on our planet. The portion that is fresh and available
for human use is at Earth's surface—in rivers, lakes,
or stored as groundwater, filling up pore spaces or cracks
in rocks.
In arid regions, surface water is not available year round,
so humans depend on groundwater sources. The Denver metropolitan
area is one area where people have been tapping in to
underground water for over a century. In this investigation,
you'll analyze changes in the water level of the Arapahoe
aquifer, one of the major aquifers of the Denver Basin
aquifer system.
|
