Groundwater and Wells:
An Introductory Discussion with Application
to Northeastern Illinois
H. Allen Wehrmann, P.E.
Illinois State Water Survey
Illinois Department of Natural Resources
2007 Priority Places Workshop: Implementing a Sustainable Water Supply for Kane County’s Future
Topical Presentation Outline
Basic Concepts and Definition
„
The Hydrologic Cycle
… What
„
Is Groundwater?
Concepts and Definitions
… Porous
Flow vs. Fractured Flow
… Aquifers vs. Aquitards
… Artesian vs. Water Table Conditions
„
„
Regional Groundwater
G
Flow Systems
S
Well and Aquifer Hydraulics
2007 Priority Places Workshop: Implementing a Sustainable Water Supply for Kane County’s Future
The Water Cycle
Climate, surface water, and groundwater are linked
2007 Priority Places Workshop: Implementing a Sustainable Water Supply for Kane County’s Future
Porous Systems
Groundwater flows through
pore spaces between grains
2007 Priority Places Workshop: Implementing a Sustainable Water Supply for Kane County’s Future
Fractured Systems
2007 Priority Places Workshop: Implementing a Sustainable Water Supply for Kane County’s Future
Fractured
Limestone or
Dolomite
2007 Priority Places Workshop: Implementing a Sustainable Water Supply for Kane County’s Future
Aquifers vs. Aquitards
„
An aquifer is a saturated bed, formation, or
group of formations that yields water in sufficient
quantity to be of consequence as a source of
supply.
„
An aquitard yields inappreciable quantities of
water, but leakage of water through the aquitard
is possible. Aquitards often act as confining
beds.
2007 Priority Places Workshop: Implementing a Sustainable Water Supply for Kane County’s Future
Unconfined vs. Confined Groundwater
„
An unconfined aquifer is one in which groundwater
possesses a free surface open to the atmosphere. The
upper surface of the zone of saturation is called the
water table.
„
A confined
fi d aquifer
if is
i one iin which
hi h groundwater
d t iis
confined under pressure by overlying and underlying
aquitards or aquicludes, and water levels in wells rise
above
b
th
the ttop off the
th aquifer.
if A confined
fi d aquifer
if is
i also
l
called an artesian aquifer.
2007 Priority Places Workshop: Implementing a Sustainable Water Supply for Kane County’s Future
Unconfined Aquifers
Land Surface
Unsaturated
((Vadose)) Zone
Water Table
Saturated
Zone
Unconfined
Aquifer
Bedrock
2007 Priority Places Workshop: Implementing a Sustainable Water Supply for Kane County’s Future
Confined Aquifers
Land Surface
Unsaturated (Vadose) Zone
Water Table
Unconfined Aquifer
Saturated Zone
Potentiometric Surface
Confining Layer - Aquitard
Confined Aquifer
Bedrock
2007 Priority Places Workshop: Implementing a Sustainable Water Supply for Kane County’s Future
Confined Aquifers and Artesian Wells
Flowing artesian well
Land surface
Confining layer
Confined
Aquifer
f
2007 Priority Places Workshop: Implementing a Sustainable Water Supply for Kane County’s Future
Regional Groundwater Flow Systems
0.1 mile
20 miles
Depth
0’
100’
10’
200’
20’
2007 Priority Places Workshop: Implementing a Sustainable Water Supply for Kane County’s Future
Cone of Depression
2007 Priority Places Workshop: Implementing a Sustainable Water Supply for Kane County’s Future
Overlapping Cones of Depression
2007 Priority Places Workshop: Implementing a Sustainable Water Supply for Kane County’s Future
Overlapping Cones of Depression:
Well Interference
2007 Priority Places Workshop: Implementing a Sustainable Water Supply for Kane County’s Future
Overlapping Cones of Depression:
Well Interference
2007 Priority Places Workshop: Implementing a Sustainable Water Supply for Kane County’s Future
Overlapping Cones of Depression:
Well Interference
2007 Priority Places Workshop: Implementing a Sustainable Water Supply for Kane County’s Future
Overlapping Cones of Depression:
Well Interference
2007 Priority Places Workshop: Implementing a Sustainable Water Supply for Kane County’s Future
Potentiometric
S f
Surface
off the
th
Deep Bedrock
A if S
Aquifer
System,
t
Fall 2000
2007 Priority Places Workshop: Implementing a Sustainable Water Supply for Kane County’s Future
Potentiometric Surface across NE Illinois
WEST
EAST
Elevation (ft)
Elevation (ft)
1000
1000
DeKalb
800
Elburn
Geneva
800
Elmhurst
Bellwood
Industrial site
in Chi cago
600
600
400
400
200
200
0
St. Peter
0
Ss
- 200
-200
- 400
-400
- 600
- 800
Ironton
-Galesviil
le
Ss
-600
-800
-1000
-1000
-1200
-1200
2007 Priority Places Workshop: Implementing a Sustainable Water Supply for Kane County’s Future
Deep Well Water Levels
Levels, Cook County
2007 Priority Places Workshop: Implementing a Sustainable Water Supply for Kane County’s Future
Deep Well Water Levels, Kendall County
600
Ellevation abov
ve Sea Level (feet)
500
400
300
200
100
Oswego #3
0
1950
1960
1970
1980
1990
2000
2007 Priority Places Workshop: Implementing a Sustainable Water Supply for Kane County’s Future
Water Sources for Public Supply
in Northeast Illinois
2007 Priority Places Workshop: Implementing a Sustainable Water Supply for Kane County’s Future