Climate Number: 28 Cubic Miles Each year the United States pumps
about 28 cubic miles of water out its groundwater aquifers –
natural underground storage areas – for irrigation, drinking
water, industrial purposes, etc. While about 84.6 percent of
these withdrawals are recharged to the aquifers through natural
recharge (primarily rainfall) or artificial recharge (recharge
to the groundwater from human activities), 15.4 percent, or
about 4.25 cubic miles, of America’s groundwater withdrawals
flow into the oceans without being returned as rainfall.
Globally, about 34 cubic miles of groundwater is lost to the
oceans every year. While groundwater losses can be replenished
over time, losses from arid or semi-arid regions may take
thousands of years to recover. Much of the groundwater being
pumped from underneath the Great Plains region, for example, is
fossil groundwater that was deposited by the melting North
American Ice Sheet over 10,000 years ago. For comparison: The 34
cubic miles of groundwater sent to the o