Geology Reference
In-Depth Information
water are naturally unfit for human consumption.
While distilled water has 0 ppm of dissolved solids,
the value for rainwater is 10 ppm, Lake Michigan is
170 ppm, the Missouri River is 360 ppm, the Pecos
River is 2600 ppm, the ocean is 35,000 ppm (35 kg, or
77 pounds, of salt per cubic meter), and the Dead Sea is
250,000 ppm. Nonetheless, these environments pro-
vide useful habitats for certain organisms and in some
cases mineral resources for humans.
In this section on Water Resources and Contami-
nation, we focus on groundwater, how it moves, its
quantity, and its quality. We also look at contamination
of surface water and groundwater, groundwater over-
draft, and saltwater intrusion of aquifers.
3.
List any other water uses or factors that might increase or
decrease the amount of water used in a single-family home.
4.
According to SIWI-IWMI (2004), between 300 and 3,000
liters of water are needed to produce a kilogram of grain.
Each one of us, depending on our diet, is responsible for the
2,000-5,000 liters of water used to produce the food we con-
sume each day. This water is "hidden"; it does not show up
in our household water calculations. If we are seeking to
understand water use in a region, this agricultural use must
be taken into consideration.
a.
Given that 1 gallon (U.S.) of water equals 3.78 liters and
assuming the food in your daily diet required 4,000 liters
of water to produce, how many "food gallons" of water
per day are you using?
QUESTIONS III
1.
The Earth's hydrologic or water cycle consists of several
reservoirs for H2O connected by flows of water or water
vapor. The typical textbook representation of the hydrologic
cycle usually is a cross-section diagram of a small part of the
Earth's surface with an ocean, landmass, and clouds. A box
model (Figure III.l) is another representation of the cycle
that emphasizes the connections (arrows) and the impor-
tance of both groundwater and the cryosphere (ice). List and
identify by name the different symbols in Figure III.l. One,
the letter P, is provided as an example below.
b. How many times greater is the quantity of "food gal-
lons" than the value of your standard household gallons
calculated in Question 2 (above)?
5.
Table III.2 provides average water requirements for pro-
duction of food items. Use it in answering this question.
In Table 2, the water requirement given for cereals is
up to 3 m
3
per kilogram. Below, in a
conversion example,
this
quantity (3 m /kg) is converted to gallons (U.S.) per pound.
P—Precipitation
water used in growing a pound of cereal:
3
»
}
X 264.2 gallons/l m
3
"
— — ——— = 792.6/2.2 = 360
1 kg X 2.2 pounds/1 kg
2.
Determine how many gallons of water you use in a day.
Consider a rainy and cold Saturday, when you spend most of
the day in your house or dormitory. To determine this
amount, go to the USGS website that has a calculator for
water.usgs.gov/edu/sq3.html
.
Record your answers in
Table III.l below and be ready to explain in class why your
"Saturday per-capita value" is higher or lower than the aver-
age of the class.
gallons/pound
a.
From data in Table III.2 and the example above, how
many gallons of water are used to produce a pound of
grain-fed beef? (Hint: Simply consider how many times
greater is the use of water for beef than the upper limit of
water for cereal.)
