Chapter 8: Groundwater Flashcards
What are the four parts to Groundwater?
- Unsaturated Zone: air, water, soil. Water is held in tension and considered unavailable.
- Capillary Fringe: up to 100% saturated, but water held in tension.
- Water Table: upper bound of Saturated Zone
- Saturated Zone: Water and soil - water flows as groundwater.
What is an aquifer?
A saturated layer permeable enough to allow water flow. Water can be pumped economically.
What is an aquitard?
Saturated layer not permeable enough for easy water flow. Water can’t be pumped out economically.
What is Groundwater?
Water contained in interconnected pores below water table in an aquifer.
What is Groundwater Flow?
The movement of water through openings in sediment and rock.
What does Artesian mean?
A confined aquifer with water that flows upward out of a well.
What does Perched mean?
Groundwater above a permeable layer - usually above aquifer.
What is the hydraulic gradient?
The slope of water table to difference in hydraulic head b/w 2 points (i)
What is Porosity?
ratio of volume of voids to total volume
What is Effective Porosity?
ratio of interconnected pore spaces to bulk volume
What is hydraulic head?
surface elevation minus distance to water table
What is pressure head?
Depth of well from surface minus distance to water table from surface
What is elevation head?
surface elevation minus depth of well
What is the difference between Darcy Flux and groundwater velocity?
Darcy velocity assumes no soil in cross section (open pipe flow), whereas groundwater velocity takes into account the porosity (ie. soil in the way)
What are the three methods of contaminant transportation?
- Advection: due to groundwater flow
- Dispersion: due to irregular flow paths
- Diffusion: due to concentration gradient