Objectives #20

Department of Earth Science |Northeastern Illinois University

PRINCIPLES OF HYDROGEOLOGY
ESCI 337
Spring, 2004

Daily Objectives #20 (April 1, 2004) Dr. Sanders

By the end of today's class, you should be able to do the following:

v Using someone else's sketch of water levels in piezometers (I will assign this part), draw a quantitatively accurate flow net, including flow lines, equipotential lines (labeled with their hydraulic head value), and water table.

v Dam Flow Net:
        n Draw a quantitatively accurate flow net for flow beneath the dam on the handout provided. Be sure to label equipotential lines with their value. For simplicity's sake, let's all use the same datum: the flat bottom of the main portion of the dam.
       n Answer the following questions about the dam flow net:
    o If the sediments have a hydraulic conductivity of 0.28 m/day, and the dam is 200 m long going back into the page, calculate the flow rate of water under the dam. (Give your answer in units of cubic meters/day.)
    o At Point A, what is the total hydraulic head? Elevation head? Pressure head?

v Ground Water Flow Model: Measure the elevations of water levels in the piezometers in the "sand tank" ground water flow model. Use the bottom of the model as a datum, and measure in centimeters. Record the value for each piezometer on the handout provided. Then, use the data to construct a flow net for the model. (Hint: you already know what the flow lines should look like, based on the dye tracks on the other side of the model. You also know what all the boundaries are. Use that information to help you draw your equipotential lines.)

v Cross Section of the Project Study Area: Homework Assignment #6, due next week, is to draw a cross section for the study area based on boring logs of the from the Illinois State Geological Survey's digital database. By the time you leave today you should have a basic familiarity with the data format and the methods you will use to plot the cross section. You also should know which of the following two wells your group will focus on:

Montgomery
Well ID

Longitude and Latitude

Lambert Coordinates

X Y

Public Land Survey

88.329^oW, 41.736^oN
(88^o, 19’, 44”W; 41^o, 44’,10”N)

3318284.250 3170639.500

T38N, R8E,

Sec. 33, Plot 4h

88.33183^oW, 41.73744^oN
(88^o, 19’, 55”W; 41^o, 44’,15”N)

3317428.000 3170504.250

T38N, R8E,

Sec. 33, Plot 5h

Department of Earth Science | Northeastern Illinois University