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

5. Advection Transport caused by the flow carrying the contaminant 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