Objectives 19

Department of Earth Science |Northeastern Illinois University

PRINCIPLES OF HYDROGEOLOGY
ESCI 337
Fall, 2007

Daily Objectives #19 (November 1, 2007) Dr. Sanders

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

v (Review) Ground Water Modeling: Numerical Model

Explain the difference between a conceptual model and a numerical model.
Explain the purpose of a numerical model grid.
Explain how Darcy's law is used in a numerical model

v Ground Water Modeling: Practice

Describe the steps in constructing a model, as given on pages 526-527 of the Fetter textbook.
Download and install the modeling program Graphic Groundwater, authored by Dr. Steven Esling at SUI/Carbondale.
Use Groundwater to create a model or a given study site.
Assign reasonable values to the variables in the model, and support your choice for each variable.

Today's Agenda:

v Ground Water Modeling: Conceptual Models

Describe the components of a conceptual model, the first part of constructing a ground water model:

Hydrostratigraphy (review from last time)
Boundaries (identify location and type) (review from last time)
Stresses (this usually refers to pumping wells and recharge from infiltration)
Initial conditions (water levels)

For our study area, describe each of the above components of the conceptual model.

v Ground Water Modeling: Numerical Models

Explain how the concept of boundaries applies to calculations of hydraulic head within a ground water model.

Explain the concept of (and reason for) using a grid in a numerical model.

For further thought:

Explain how the concept of anisotropy applies to your calculations.
Explain how the concept of inhomogeneity applies to your calculations.

v Ground Water Modeling: Practice

How do we come up with "hard numbers" for each variable in a ground water model? Find reasonable values or ranges of values for these variables:

top elevation of the aquifer
bottom elevation of the aquifer
hydraulic conductivity (horizontal)
vertical hydraulic conductivity
recharge to the aquifer through infiltration
porosity
initial head
rate of pumping from wells

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Items carried over from last time:

Homework due today, Thursday, November 1:

1) Write a 1-2 paragraph description of the geology of the study area. (Refer to the cross section.)
2) Write a 2-3 paragraph description of the conceptual model, including at this point, the hydrostratigraphy and the boundaries to the flow system (we will add the other components next time).

The documents describing step-by-step model construction appear at the links below. We looked at these last time; they are here for your convenience. First Steps and Building Your Model A graphic image of our study area is posted here!

Department of Earth Science | Northeastern Illinois University