Hydrologic Cycle
Sand porosity
and permeability
Shallow aquifer
Confining bed/
aquitard
Deeper aquifer
Fig. 19.06
W. W. Norton
Unsaturated zone
Fig. 19.07 a
HUMID CLIMATE
Fig. 19.11
W. W. Norton
Important to identify recharge areas!!!! Do not pollute them!
Gaining Stream
Losing stream
ARID CLIMATE
Fig. 19.13
W. W. Norton
Determine which way
Groundwater flows
Determine location of
Recharge/discharge areas
Cone of depression
Fig. 19.15 a
W. W. Norton
Fig. 19.15 b
W. W. Norton
Fig. 19.15 c
W. W. Norton
Fig. 19.22 a, b
W. W. Norton
South Florida before pumping
South Florida after pumping
AQUIFER TYPES
Fig. 19.06
Confining bed
W. W. Norton
Confined/artesian aquifer
Note: aquiclude = confining bed!
The potentiometric surface is a pressure surface
It’s the level to which water will rise in your well!
Fig. 19.16 c
W. W. Norton
Flooding due to subsidence in Indonesia
Fig. 19.09
W. W. Norton
Unit Conversions
Common units used to measure water are:
•
•
•
•
cfs (cubic feet per second)
gallons
acre-foot
inches (in precip gage)
Need to be able to convert between them
Acre-foot
1 acre-foot = 43,560 ft2/acre x 1 foot = 43,560 ft3
How many gallons is this???
Cubic feet  gallons
• 7.48 gallons = 1 ft3
• 43,560 ft3 x 7.48 gal/1 ft3 = 325,829 gal
Length-Area-Volume
L vs. L2 vs. L3
12 inches
12 inches x 12 inches =
144 in2
12 inches
1 ft2
=1 ft2
Length-Area-Volume
L vs. L2 vs. L3
12 inches
12 inches
1 ft3
12 in x 12 in x 12 in =
1728 in3 =
1 ft3
CRATER LAKE
Surface area = 579,348,000 ft2
Avg. ann. Precip = 68 in.
What volume of precip. is added
to the lake in acre-feet each year?
1) Need to convert units to make
them consistent. It’s easiest to convert
Feet to acre-feet, so let’s convert inches to
Feet!
68 in x 1 foot /12 inches = 68/12 feet = 5.67 ft
2) Calculate volume of precip. in ft3 by
multiplying Surface area of lake x depth
of precip.
579,348,000 ft2 x 5.67 ft = 3,284,903,160 ft3
3) Convert ft3 to acre-ft
3,284,903,160 ft3 x 1 ac-ft/43,560 ft3 =
75,411 acre-ft/year from ppt.