Chapter 8: Groundwater Flashcards

1
Q

What are the four parts to Groundwater?

A
  1. Unsaturated Zone: air, water, soil. Water is held in tension and considered unavailable.
  2. Capillary Fringe: up to 100% saturated, but water held in tension.
  3. Water Table: upper bound of Saturated Zone
  4. Saturated Zone: Water and soil - water flows as groundwater.
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2
Q

What is an aquifer?

A

A saturated layer permeable enough to allow water flow. Water can be pumped economically.

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3
Q

What is an aquitard?

A

Saturated layer not permeable enough for easy water flow. Water can’t be pumped out economically.

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4
Q

What is Groundwater?

A

Water contained in interconnected pores below water table in an aquifer.

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5
Q

What is Groundwater Flow?

A

The movement of water through openings in sediment and rock.

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6
Q

What does Artesian mean?

A

A confined aquifer with water that flows upward out of a well.

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7
Q

What does Perched mean?

A

Groundwater above a permeable layer - usually above aquifer.

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8
Q

What is the hydraulic gradient?

A

The slope of water table to difference in hydraulic head b/w 2 points (i)

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9
Q

What is Porosity?

A

ratio of volume of voids to total volume

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10
Q

What is Effective Porosity?

A

ratio of interconnected pore spaces to bulk volume

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11
Q

What is hydraulic head?

A

surface elevation minus distance to water table

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12
Q

What is pressure head?

A

Depth of well from surface minus distance to water table from surface

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13
Q

What is elevation head?

A

surface elevation minus depth of well

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14
Q

What is the difference between Darcy Flux and groundwater velocity?

A

Darcy velocity assumes no soil in cross section (open pipe flow), whereas groundwater velocity takes into account the porosity (ie. soil in the way)

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15
Q

What are the three methods of contaminant transportation?

A
  1. Advection: due to groundwater flow
  2. Dispersion: due to irregular flow paths
  3. Diffusion: due to concentration gradient
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16
Q

What is Plume?

A

Dissolved contaminants

17
Q

What are some attributes of dispersion?

A
  • micro, macro, and mega scales
  • smaller pores = higher velocity
  • higher velocities = higher dispersion
18
Q

What are some attributes of diffusion?

A
  • Contaminant plume moves from high concentration to low
  • Important in low velocity soils (clay/bedrock)
19
Q

What is Adsorption?

A

The property of a solute to attach to a surface of a solid

20
Q

What is Absorption?

A

The property of a solute to attach to surface of a solid, then penetrate the solid

21
Q

What is Retardation?

A

When contaminant velocity is slower than groundwater velocity.

22
Q

What are NAPLs?

A

Non-Aqueous Phase Liquids

23
Q

What are LNAPLs and DNAPLs?

A

Less dense than water - LNAPL
More dense than water - DNAPL

24
Q

What are some attributes of NAPLs?

A
  • Ganglion form as NAPL migrates
  • Immobile
  • Long term source of groundwater contamination
  • Difficult to remove or remediate
25
Q

What are the steps in Contaminated Site Management?

A
  1. Site Investigation
  2. Remediation Plan & Implementations
  3. Confirmation of Remediation - certification
  4. Long-term Monitoring
26
Q

What are some remediation technologies for groundwater?

A
  • Fluid pumping
  • Mass destruction
  • Enhanced fluid pumping
  • Enhanced bioremediation
27
Q

What does Groundwater Pumping involve?

A
  • Uses advective treatment methods to remediate
  • Contaminant and fluid brought to surface for treatment
  • Hydrodynamic/hydraulic control
28
Q

What is SVE?

A

Air Flushing:
- Soil Vapour Extraction
- Unsaturated Zone: Soil remediation

29
Q

What is Air Sparging?

A

Air Flushing:
- Saturated Zone: Plume remediation

30
Q

What are PRB’s?

A

Permeable Reactive Barriers.

They passively intercept contaminants passing through the barrier where they react and are broken down by a reactive material.

31
Q

What is ISCO?

A

In-situ chemical oxidation.

Oxidation converts hazardous contaminants to non-hazardous compounds that are more stable.

32
Q

What are common oxidizing agents used?

A
  • Ozone
  • Hydrogen Peroxide
  • Permanganate
33
Q

What are some benefits of ISCO?

A
  • applicable to a variety of soil types
  • Can treat VOC’s and SemiVOC’s
  • Rapid destruction
  • No significant waste
34
Q

What is MNA?

A

Monitored Natural Attenuation

Naturally Occurring processes that act without human intervention to reduce contaminants in soil/groundwater.

35
Q

What are Reactive Zones?

A

Zones created by injection of air/oxygen that treats contaminants through biodegredation.

36
Q

What is Thermal Remediation?

A

Use of heat to destroy contaminants.
- Conduction heating
- Steam injection

37
Q

What is Phytoremediation?

A

Use of plants to address contamination issues.