GLY 110-101: GENERAL GEOLOGY
EXTRA CREDIT ASSIGNMENT: GROUNDWATER AVAILABILITY
The questions for this assignment pertain to the United States Geological Survey (USGS)
publication, Groundwater Availability in the United States (2008). The link below
provides access to the document:
http://pubs.usgs.gov/circ/1323/
1. Groundwater exists almost everywhere across the U.S.
a. true
b. false
2. Groundwater is usually available even where surface water is not.
a. true
b. false
3. The availability of groundwater varies widely across the U.S.
a. true
b. false
4. Determining the availability of groundwater in any given area can usually be done
reliably and quickly.
a. true
b. false
5. What is the potential effect of groundwater withdrawal on streams connected to the
aquifer that is being pumped?
a.
b.
c.
d.
decreased flow from the aquifer to the stream
increased flow from the stream to the aquifer
streamflow capture
all of the above
6. What type of aquifer systems are most extensive in the western U.S. (first part of
Figure 2)?
a.
b.
c.
d.
sand and gravel
sandstone
sandstone / carbonate
carbonate
7. What type of aquifer systems are most extensive in the eastern U.S. (second part of
Figure 2)?
a.
b.
c.
d.
sand and gravel
sandstone
sandstone / carbonate
carbonate
8. Which of the following is true about groundwater withdrawals for irrigation in the
U.S.?
a. Western states pump more water than eastern states but the volume pumped in
the western states has been decreasing.
b. Eastern states pump more water than western states but the volume pumped in
the eastern states has been decreasing.
c. Western states pump more water than eastern states and the volume pumped
in the western states has been increasing.
d. Eastern states pump more water than western states and the volume pumped in
the eastern states has been increasing.
9. Figure 5 shows that, at 17 million gallons of water per day, the High Plains aquifer is
far and away the biggest source of water for irrigation in the U.S. According to
Figure 2, where is this aquifer system located?
a.
b.
c.
d.
California
Michigan and Wisconsin
Texas and Louisiana
Texas, Oklahoma, Nebraska, and Kansas
10. The eastern seaboard, from Florida to the Carolinas to the Mid-Atlantic states, is
located in a wet climate with abundant renewable freshwater resources. Why, then, is
significant decline in groundwater levels occurring in some of the principal aquifers
in this area?
a.
b.
c.
d.
increased pumping for agricultural use
increased pumping to support growing population
wasteful use of water for nonessential needs like water parks and golf courses
increased evaporation due to global warming
11. Which one of the following statements is true about groundwater recharge?
a. Recharge generally exceeds the amount of evapotranspiration (evaporation
plus transpiration from plants).
b. Potential evapotranspiration cannot exceed the amount of precipitation.
c. In extremely wet areas recharge can exceed the amount of precipitation.
d. Recharge is generally highest in areas where precipitation is highest.
12. What are some of the consequences of groundwater pumping?
a.
b.
c.
d.
e.
less base flow
less water for native plants
less water for other wells
lowered aquifer levels
all of the above
13. Starting on page 39 are examples of regional aquifer assessments. The Central Valley
Aquifer System is of note because 8% of the nation’s agricultural output is produced
on only 1% of its land area, thanks in large part to irrigation of crops with
groundwater. How can so much water be pumped from this aquifer when the climate
is arid to semiarid?
a. More marijuana is being grown, which uses less water than fruits and
vegetables.
b. The aquifer system gets additional recharge in the form of snowmelt from the
mountains.
c. Ocean water from coastal areas is pumped over the mountains to supplement
the water pumped from the ground.
d. Decreasing population in the Central Valley means people don’t need as much
water, so agriculture can use more.
14. The assessment of the Coastal Plain Aquifer System mentions the transition zone
between salt and fresh water in aquifers along the coastline. After, looking at Figure
20 and reading the accompanying text, select the best answer of the following:
a. A normal transition zone consists of a wedge of fresh water sitting on top of
salt water and angled seaward.
b. A normal transition zone consists of a wedge of salt water sitting on top of
fresh water and angled seaward.
c. A normal transition zone consists of a wedge of fresh water sitting on top of
salt water and angled landward.
d. A normal transition zone consists of a wedge of salt water sitting on top of
fresh water and angled landward.
15. The assessment of the Coastal Plain Aquifer System also mentions that “saltwater
encroachment” can be a problem. How can this problem develop?
a.
b.
c.
d.
Fresh water invades salt water-pumping wells due to over-pumping.
Fresh water invades salt water-pumping wells due to under-pumping.
Salt water invades fresh water-pumping wells due to over-pumping.
Salt water invades fresh water-pumping wells due to under-pumping.