of Earth Science |Northeastern Illinois
Homework #4 (Due
March 12, 2009)
"The Situation" described in this problem is
The Situation: Your clients are purchasing property and intend to build a
small factory. They intend to use ground water in some of their
processing, so they will need a well. They ask you to study the
hydrogeology of the area and create a model so they can investigate different
Your Task: Collect geologic data and create cross sections that
illustrate the geologic and hydrogeologic setting of the study area. Your
cross sections should portray the hydrogeologic system--that is, you should be
looking for flow system boundaries. Keep that in mind as you decide how
far a cross section should extend.
The property boundaries are not firmly established yet, because the sale has not
yet been completed. However, it is in the area of latitude 42 degrees,
6.856 minutes N, and longitude 88 degrees, 54.963 minutes W.
Cross Section Format Information:
Cross sections should extend from point to
point, not necessarily in a straight line. (Some call this a
"fence diagram" instead of a cross section.) Use as many points as you
need to represent the system.
The following should be shown on cross sections:
Draw your cross section
(You probably will have to change it after it is reviewed.)
- Elevation scales (one on each side of
- Horizontal scale (a graphical bar
- Statement of vertical exaggeration (for
example, "Vertical Exaggeration = x25", or "Vertical Exaggeration = 50:1")
- Letters designating the line along
which the cross section is drawn--for example, A-A', or B-B'.
- Single black lines outlining
lithostratigraphic and/or hydrostratigraphic units (do
not fill the area with a pattern)
- A label for each geologic unit
portrayed. If you know the formal formation name, give it; otherwise, use a
label such as "Clay", "Granite", etc.
- A label for any significant local
features, for example, lakes, streams, county lines, major highways, and so
- A single, solid, black line showing the
location and depth of each well that appears on cross section; at the top,
give the five-digit unique number code for that well (digits six through ten
of the "API number").
- Total depth of each well that appears
on the cross section (print "TD = __" at the bottom of each well).
- Ideally, the cross section should fit
on one sheet of 11" x17" paper (or smaller).
- On a separate sheet, give a map showing
the line of cross section. Be sure to label the lines as A-A' or B-B' .
You may find it helpful to use the USGS
Map Locator (click "Download Digital Scans of Topo Maps"; also see
Hemzacek's suggestions on downloading from this site) or
We will be working on this project in class on Tuesday, but you should come in
with much of the research already done. By the end of the day on Tuesday,
you should have delineated the boundaries of the flow system, collected all the
boring log data you need, identified the hydrostratigraphic units, and sketched
out cross sections. You also may wish to get a start on the final
Please cooperate with each other to collect data and analyze the problem.
However, each person is responsible for his/her own cross section drawing.
Copyright 2009 Laura L. Sanders. Last updated March 5, 2009.