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

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

1. Hydrologic Cycle and Water Distribution
2. Soil Horizons
3. Aquifers
4. Soil Texture
5. Porosity and Density
6. Saturation and Water Content
7. Hydraulic Head

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1. Hydrologic Cycle and Water Distribution
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Hydrogeology What is it?

• Hydrologic cycle circulation of water in the
  environment
• Hydrogeology examines the relationships of
  geologic materials and flowing water

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Global Hydrologic Cycle
Domenico and Schwartz, 1990.
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Basin Hydrologic Cycle
Charbeneau, 2000.
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Basin Hydrologic Cycle GW/SW Interaction
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Artesian Zone of Edwards Aquifer

• The artesian zone is a complex system of
  interconnected voids varying from microscopic
  pores to open caverns
• Located between two relatively less permeable
  layers that confine and pressurize the system
• Underlies 2100 square miles of land

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Global Hydrologic Cycle Schematic
Domenico and Schwartz, 1990.
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Basin Hydrologic Cycle Schematic
Domenico and Schwartz, 1990.
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Basin Hydrologic Cycle Quantitative
Representation
Basin
I
Surface/ Soil
Aquifer
Domenico and Schwartz, 1990.
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2. Soil Horizons
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Charbeneau, 2000.
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Figure 15.1
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3. Aquifers
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Aquifers

• Definition A geological unit which can store
  and supply significant quantities of water.
• Principal aquifers by rock type
• Unconsolidated
• Sandstone
• Sandstone and Carbonate
• Semiconsolidated
• Carbonate-rock
• Volcanic
• Other rocks

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Occurrence of Ground Water

• Ground water occurs when water recharges the
  subsurface through cracks and pores in soil and
  rock
• Shallow water level is called the water table

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Recharge

• Natural
• Precipitation
• Melting snow
• Infiltration by streams and lakes

• Artificial
• Recharge wells
• Water spread over land in pits, furrows, ditches
• Small dams in stream channels to detain and
  deflect water

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Example Layered Aquifer System
Bedient et al., 1999.
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Other Aquifer Features
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Leaky and Perched Aquifers

• Leaky confined aquifer represents a stratum that
  allows water to flow from above through a leaky
  confining zone into the underlying aquifer
• Perched aquifer occurs when an unconfined water
  zone sits on top of a clay lens, separated from
  the main aquifer below

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4. Soil Texture
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Bedient et al., 1999.
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Particle Size Distribution
Poorly sorted silty fine to medium sand
Well sorted fine sand
Bedient et al., 1999.
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Particle Size Distribution
Charbeneau, 2000.
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4. Porosity and Density
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REV Representative Elementary Volume
Charbeneau, 2000.
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REV Scale Effect
Freeze and Cherry, 1979.
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Types of Porous Media
Freeze and Cherry, 1979.
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Typical Values of Porosity
Bedient et al., 1999.,
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6. Saturation and Water Content
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Soil Moisture Held by Capillary Pressure
Charbeneau, 2000.
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Moisture Content in Capillary Zone
Charbeneau, 2000.
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7. Hydraulic Head
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Pressure and Elevation Heads - Laboratory
? pressure head z elevation head h 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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Two Confined Aquifers with Different Heads
Groundwater will tend to flow from the top
aquifer to the bottom aquifer. We cant make any
conclusion about horizontal head gradients from
this picture.
Charbeneau, 2000.
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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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Lecture 2 Reading Assignments

• Hydrologic Cycle and Water Distribution
• Bedient et al., pp. 1-6
• Domenico Schwartz, pp. 9-21
• Soil Horizons
• Bedient et al., pp. 15-18
• Charbeneau, pp. 5-6
• Aquifers/Soil Texture/Porosity and
  Density/Saturation and Water Content
• Bedient et al., pp. 18-23
• Charbeneau, pp. 2-12
• Hydraulic Head
• Bedient et al., pg. 24
• Domenico and Schwartz, pp. 58-59
• Freeze and Cherry, pp. 18-25

Note Only reading in Bedient et al. is required.
Other reading assignments are highly recommended
and contain extended explanations that might be
helpful for your understanding of the material.