Department
of Earth Science |Northeastern
Illinois University
PRINCIPLES
OF HYDROGEOLOGY
ESCI
337
Fall,
2007
Review Sheet for Exam #1 (October 4,
2007)
Dr. Sanders
Exam #1 is open-note, open-book. You may bring any printed
materials you like. You should be able to do the following:
v Write
the full names of at least two of your classmates.
v Making
Hydrogeologic Calculations:
- Describe
the purpose and function of a rain barrel, and make quantitative
calculations to estimate how a rain barrel is involved in the water
budget of a residential property in Chicago. The
information you need is on this PowerPoint presentation (5.2MB). Make all the
calculations
required to answer questions on the slides with white
backgrounds.
- Use concepts of
length, area, volume, and flow rate to quantify hydrologic variables.
- Solve a
hydrologic
problem in a sequence of logical steps, using reasonable units and
dimensional analysis.
v Wells and Ground Water Systems:
- Measure
depth to water in a well and the total depth of the well.
Extract water from the well and describe the effect of that extraction
on the water level over time. Sketch a diagram illustrating the
components
of a well. Develop a test protocol for evaluating how a well
responds to pumping. Information
on what we are doing outdoors appears at this link.
v Water Flow:
- Using
the ground water flow model, inject dye into the model and track its
flow through time. Sketch a diagram showing the following
features:
q surface water
q
ground water
q boundaries of the
flow system
q flow directions (use
arrows)
q flow
velocities (show
areas of fast/medium/slow flow) (Note:
we did not debrief this item, and the data were inconsistent; we'll
come back to this activity in a few weeks.)
- Describe
in words
what makes water flow. Using simple sketches, show how water
would flow from one container (like a rain barrel) into another if they
were connected by hoses.
v Water Flow--Lab Explorations: Investigate, discover,
and
articulate the general principles that describe the movement of water
and the
factors that drive it. Use simple
lab set-ups to
investigate the movement of water through open conduits and through
porous media.
Activities (Click
here for an MSWord copy of the instructions):
- Bucket-to-Bucket
Transfer
- Holey
Water Bottle
- Draining
Work
- Capillary
Action
- Infiltration
Observation
- Darcy
Discovery
Follow-up
questions
(these were assigned for Homework #2):
- What is
the effect of tube diameter on flow velocity in Bucket-to-Bucket
transfer?
- What
is the effect of grain sorting on how
much water drains out of sediment in Draining Work?
- What is
the effect of volume of water in the upper bucket on flow rate in
Bucket-to-Bucket transfer?
- What makes the water flow in
Bucket-to-Bucket transfer?
v Properties of Porous Materials:
- Define the following terms, using appropriate units of
measurement:
- porosity
- effective
porosity
- specific yield
- specific retention
- hydraulic conductivity
- permeability
- Write formulas defining each of the properties. Write a
formula that relates specific
retention
and specific yield to porosity.
- Explain the difference between hydraulic conductivity and
permeability.
- Characterize rocks and sediments in terms of their
porosity, effective porosity, specific yield, and specific retention,
giving typical ranges of values of these properties for each type of
rock and sediment.
- Define the terms aquifer and aquitard.
v Hydraulic Head, Hydraulic Gradient, and
Flow:
- Define
the term hydraulic head
and describe its two components.
- Explain
the effect hydraulic head has on the flow of water.
- Discuss
what makes
water flow and how that relates to the concept of hydraulic head.
Determine the hydraulic head at various points in a cross section
illustrating a shallow ground water system. (Click
here to get the worksheet.)
- Determine
the hydraulic head within a bucket of water. (Hint: you will need
to start by setting an arbitrary datum.)
<>If two
buckets are connected by a tube (see
a simple worksheet here), find the total
hydraulic head at each end of the tube. What does this tell you
about direction of flow? What if the end of the tube is higher
than water level in the lower bucket? What happens if the
tube is made longer? Looped? Made shorter? Packed with sand?
- <>Given
a
system of two water buckets with a tube between them (see the
worksheet here), say whether water will
flow from one bucket to the other (and if so, which way). Come up
with a general rule that tells whether water will flow or not and if
so, which way.
- Return to the system
of two buckets connected by a long tube, the tube packed with
sand. Find the hydraulic head at a point exactly halfway between
the two ends of the tube, and at points exactly one-fourth of the way
from each end. Then, consider a shorter tube packed with
sand, but starting and ending at the same places as the longer
one. Find the hydraulic head at the 1/4, 1/2, and 3/4
points.
How is this system like/unlike the system with the longer tube?
Explain the term hydraulic
gradient.
v Water Table: Discuss
the meaning of the following terms:
- water table
- unsaturated
(vadose) zone
- saturated
(phreatic) zone
- capillary
zone (capillary fringe)
Explain how
each of the above relates to atmospheric pressure and pressure of water
in pores (pore water pressure), and describe saturation conditions in
each of the zones. Tell what the hydraulic head is at a point
directly on the water table.
v Measuring Hydraulic Conductivity and
Permeability:
- Devise a new protocol
for measuring hydraulic conductivity (see Homework #3). Using that
protocol,
measure the hydraulic conductivity of two samples of sediments, and
write a lab report as per the instructions given on the homework
page.
- Draw a
sketch of your experimental set-up. Determine the hydraulic head
at these two points:
as water enters the sediment sample, and as it exits the sediment
sample. Find the hydraulic gradient within the sample. How
could you have increased discharge (Q) through the sample by altering
your experimental set-up?
v Darcy's Law:
- Formulate
a way to combine hydraulic
conductivity, cross sectional area,
and hydraulic
gradient to give the discharge of water flowing through a tube
packed with sand. Check to be sure the units of measurement work
out! Find a
statement of Darcy's
Law in your textbook, and tell how it compares with what you
just formulated.
Department
of Earth Science | Northeastern
Illinois
University
© 2007 Laura L.
Sanders.
Last updated October 2, 2007.