11/14/06 1/2
GEOL474/674 Fall 2006 Assignment #5 Due: 11/30/05
Your task is to interpret the attached aquifer test data. Drilling logs from the producing
well indicate a stiff clay beneath a 24 foot thick sand layer, with a 13' thick layer of
clayey-sand above. The top of the sand layer is located 552 ft below land surface, and
initial water level in the production well was 531 ft below land surface. An existing well
located 103 ft due south of the producing well was used to collect drawdown data. Logs
for the observation well are not detailed, but suggest that the clayey-sand is present, and
that the well is completed in the sand aquifer. The sediments were likely deposited during
a wetter climate by the river that runs through the valley. The pumping rate was held
constant at 350 GPM for the entire 5-1/2 day duration of this aquifer test.
This assignment is to be completed as if I had contracted you to perform the analysis.
Your answer should be transmitted in the form of a business letter or memorandum, with
attachments. The cover letter/memo should concisely address the relevant issues and refer
directly to the supporting documentation. The cover letter should concisely document and
justify the procedure and choices that you make in completing this assignment. It should
also clearly state potential sources of uncertainty that may affect the clients decision
making process. Please cite references where appropriate, show your work, be careful
with significant digits, and be sure to include units as needed.
There are various means to approach this problem, matching of type curves, straight-line
analysis, and the computer program provided with your book. It would be a mistake to
rely solely on one method. In order to facilitate this process I will place a set of USGS
type curves on reserve in the library; these curves are from USGS publication number
708, “Ground-Water hydraulics” by Lohman. Remember that this assignment will also be
posted on my web site; however I can not accurately provide graph paper through the
web site as the scale is dependent on the printer.
You are to work on this project in 2-4 person teams that I will choose. Each team should
produce a single document with attachments, and all members of the team will be
assigned the same grade. Feel free to use whatever resources that you can locate, and to
discuss your work with other class members or myself. The budget on this assignment is
severely restricted, and no team is to spend more than $10 dollars on preparing their
result.
