Groundwater and Wells · 2007-09-28 · Groundwater and Wells: An Introductory Discussion with Application to Northeastern Illinois H. Allen Wehrmann, P.E. Illinois State Water SurveyIllinois

Groundwater and Wells:An Introductory Discussion with Application to Northeastern Illinois

H. Allen Wehrmann, P.E.Illinois State Water SurveyIllinois State Water Survey

Illinois Department of Natural Resources

2007 Priority Places Workshop: Implementing a Sustainable Water Supply for Kane County’s Future

Topical Presentation OutlineTopical Presentation Outline Basic Concepts and Definition

The Hydrologic CycleWhat Is Groundwater?

Concepts and DefinitionsPorous Flow vs. Fractured FlowAquifers vs. AquitardsArtesian vs. Water Table Conditions

G SRegional Groundwater Flow SystemsWell and Aquifer Hydraulics


The Water CycleThe Water CycleClimate, surface water, and groundwater are linked


Porous Systems

Groundwater flows throughpore spaces between grains


Fractured SystemsFractured Systems


FracturedFractured Limestone or

DolomiteDolomite


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 ofquantity 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.


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 theupper surface of the zone of saturation is called the water table.

A fi d if i i hi h d t iA confined aquifer is one in which groundwater is confined under pressure by overlying and underlying aquitards or aquicludes, and water levels in wells rise b th t f th if A fi d if i labove the top of the aquifer. A confined aquifer is also

called an artesian aquifer.


Unconfined Aquifers

Land Surface

Unsaturated (Vadose) Zone

Water Table

( )

Saturated

UnconfinedAquifer

Saturated Zone


Bedrock

Confined Aquifers

Land Surface

Water Table

Unsaturated (Vadose) Zone

Unconfined Aquifer

Water Table

Saturated Zone

Confining Layer - AquitardPotentiometric Surface

Confined Aquifer

Confining Layer - Aquitard


Bedrock

Confined Aquifers and Artesian Wells

Land surfaceFlowing artesian well

Land surface

Confining layer

ConfinedfAquifer


Regional Groundwater Flow SystemsRegional Groundwater Flow Systems

0.1 mileDepth

20 milesDepth

0’

100’10’


200’20’

Cone of Depression


Overlapping Cones of Depression


Overlapping Cones of Depression:Overlapping Cones of Depression:Well Interference








Potentiometric S f f thSurface of theDeep Bedrock A if S tAquifer System, Fall 2000


Potentiometric Surface across NE IllinoisPotentiometric Surface across NE Illinois

WESTEAST

Elevation (ft) Elevation (ft)

WESTEAST

Elevation (ft) Elevation (ft)

DeKalb Elburn

Geneva ElmhurstBellwood

Industr ial site in Chi cago

600

800

1000

600

800

1000DeKalb Elburn

Geneva ElmhurstBellwood

Industr ial site in Chi cago

600

800

1000

600

800

1000

0

200

400

0

200

400

St Pete S0

200

400

0

200

400

St Pete S

-400

-200

-400

-200

Ironton-Gale i

St. Peter Ss

-400

-200

-400

-200

Ironton-Gale i

St. Peter Ss

-1000

-800

-600

-1000

-800

-600on-Galesville Ss

-1000

-800

-600

-1000

-800

-600on-Galesville Ss


-1200-1200 -1200-1200

Deep Well Water Levels Cook CountyDeep Well Water Levels, Cook County


Deep Well Water Levels, Kendall CountyDeep Well Water Levels, Kendall County600

500

(feet

)

300

400

ve S

ea L

evel

200

leva

tion

abov

100

El

Oswego #3


1950 1960 1970 1980 1990 20000

Water Sources for Public SupplyWater Sources for Public Supply in Northeast Illinois


Documents

Groundwater and Wells · 2007-09-28 · Groundwater and Wells: An Introductory Discussion with Application to Northeastern Illinois H. Allen Wehrmann, P.E. Illinois State Water SurveyIllinois