GROUNDWATER HYDROLOGY AND CONTAMINANT TRANSPORT CEVE 518 P.C. de Blanc C.J. Newell

1
GROUNDWATER HYDROLOGY AND CONTAMINANT
TRANSPORTCEVE 518P.C. de BlancC.J. Newell
Lecture 3

1. Porosity and Density Continued
2. Saturation and Water Content
3. Darcys Law
4. Hydraulic Head

2
GROUNDWATER HYDROLOGY AND CONTAMINANT
TRANSPORTCEVE 518P.C. de BlancC.J. Newell
Lecture 3

1. Porosity and Density Continued
2. Saturation and Water Content
3. Darcys Law
4. Hydraulic Head

3
GROUNDWATER HYDROLOGY AND CONTAMINANT
TRANSPORTCEVE 518P.C. de BlancC.J. Newell
Lecture 3

1. Porosity and Density Continued
2. Saturation and Water Content
3. Darcys Law
4. Hydraulic Head

4
Capillary Rise in a Tube
Domenico and Schwartz, 1992.
5
Soil Moisture Held by Capillary Pressure
Charbeneau, 2000.
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Soil Water Characteristic Curve is a Function of
pore size
Capillary forces hold water tightly in small clay
pores.
Larger sand pores produce lower capillary
pressures.
?r,lay
?r,and
0
nclay
nsand
Charbeneau, 2000.
7
Soil Water Characteristic Curve is a Function
of Sorting (Pore Size Distribution)
Relatively wide range of pore sizes from small to
large results in widely varying capillary
pressures.
Narrow range of particle sizes results in
relatively small range of capillary pressures.
Fetter, 1999.
8
Soil Water Characteristic Curves Also Represent
Water Content as a Function of Height Above Water
Table
Fetter, 1999.
9
Capillary pressure May Be More Easily Conceived
of as the Independent Variable
nclay
nsand
clay
water content
sand
-103
0
capillary pressure (increasing height above water
table)
Charbeneau, 2000.
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GROUNDWATER HYDROLOGY AND CONTAMINANT
TRANSPORTCEVE 518P.C. de BlancC.J. Newell
Lecture 3

1. Porosity and Density Continued
2. Saturation and Water Content
3. Darcys Law
4. Hydraulic Head

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Who Was Darcy?

• Henry Philibert Gaspard Darcy was born June 10,
  1803 in Dijon, France.
• Admitted to the French School of Bridges and
  Roads in Paris, part of the Corps of Bridges and
  Roads. After graduation, he was eventually
  assigned by the Corps to a position in Dijon.
• In 1828, Darcy designed a 12.7 km system of
  aqueducts to supply the city of Dijon with
  surface water. The system included 28,000 m of
  pressurized surface lines and required no pumps
  or filters.
• Made important contributions to flow and friction
  loss in pipes, created an improved pitot tube
  design, and was the first to postulate the
  existance of a boundary layer in fluid flow.
• In 1856, carried out experiments while
  researching sand filters that lead to Darcys
  Law.
• Died unexpectedly January 3, 1858 from pneumonia
  during a trip to Paris.

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Darcys Experimental Apparatus
Domenico and Schwartz, 1992.
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Darcys Experimental Data
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Darcys Experimental Data
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Darcys Data in English (One Experiment)
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Velocity through Porous Medium
Pipe
Porous Medium
Solid
Void Space
Porosity 0.5
Porosity 0.5
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Darcys Legacy
Place Darcy, Dijon, France.
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Can you Help the French Postal Service?
Young Darcy
Old Darcy
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GROUNDWATER HYDROLOGY AND CONTAMINANT
TRANSPORTCEVE 518P.C. de BlancC.J. Newell
Lecture 3

1. Porosity and Density Continued
2. Saturation and Water Content
3. Darcys Law
4. Hydraulic Head

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Pressure and Elevation Heads - Laboratory
? pressure head z elevation head h ? z
total head
Freeze and Cherry, 1979.
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Pressure and Elevation Heads - Field
? pressure head z elevation head h total
head
Freeze and Cherry, 1979.
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Horizontal and Vertical Head Gradients
Freeze and Cherry, 1979.
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Two Confined Aquifers with Different Heads
Groundwater will tend to flow from the top
aquifer to the bottom aquifer. (Assuming that
horizontal distance between piezometers is small)
Charbeneau, 2000.
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Hydraulic Head is a Potential Field
Hubbert (1940) potential a physical quantity,
capable of measurement at every point in a flow
system, whose properties are such that flow
always occurs from regions in which the quantity
has a higher values of those in which it has
lower, regardless of the direction in space.
Potential fields and associated physical laws
Fluid Flux
Head (Darcys Law) Temperature (Fouriers Law)
Conduction of heat in solids Concentration
(Ficks Law) Diffusion of chemicals
Heat Flux
Mass Flux
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Horizontal and Vertical Head Gradients
Freeze and Cherry, 1979.
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Horizontal and Vertical Head Gradients
Freeze and Cherry, 1979.
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Potentiometric Surface Dakota Sandstone
Domenico and Schwartz, 1992.