Groundwater contamination

1
Groundwater contamination

• CE 473/573 Groundwater

2
Sources of contamination

• 1. Natural processes
• Leaching of natural deposits
• Evapotranspiration
• 2. Runoff from agricultural urban watersheds
• 3. Waste disposal practices
• 4. Accidental spills and leaks

3
Transport processes (10.6)

• 1. Diffusion
• 2. Advection
• 3. Dispersion
• 4. Retardation
• 5. Degradation

4
Diffusion

• Transport by molecular action from high to low
  concentration

t 0
5
Advection

• Transport caused by the flow carrying the
  contaminant

U
t 0
6
Dispersion

• Transport due to spreading via several mechanisms

7
Other processes

• Retardation chemical and physical processes
  that cause slower transport
• Degradation decay or loss of contaminant