2.1 Groundwater Systems

Water Footprint

The total amount of water needed to produce a product or food item.

Recharge

The process where water seeps into the ground to replenish groundwater.

Discharge

The process where groundwater exits the system, such as into rivers, lakes, or the ocean.

Aquifer

A water-bearing formation in the ground where groundwater can be stored and moved.

Aquitard

A layer of rock or sediment that restricts or slows water flow.

Unconfined Aquifer

An aquifer where water can flow freely to the surface; the upper boundary is the ground surface.

Confined Aquifer

An aquifer trapped between layers of aquitards, limiting water flow.

Porosity

The measure of void space in a material, indicating how much water it can store.

Infiltration

The process of water entering the soil and groundwater system.

Residence Time

The average amount of time water spends in a groundwater system.

What % of the Earth’s fresh water is in groundwater?

30%

When it rains, what proportion of the water becomes ground water?

10% seeps into the ground by infiltration or percolation

To what point does infiltration supply water to the ground?

until the pore space is saturated, aka the water table

How is ground water able to be dated?

It contains a chemical signature from its last atmosphere contact

What is an aquiclude?

An extreme case of an aquitard that stops water flow altogether

What kind of aquifer is usually protected from toxic chemical spills

Confined aquifer - the aquitard protects it

What is an artisan well?

When a well is drilled into a high-pressure (confined) aquifer and the pressure moves from high to low pressure

what controls porostiy of a system where groundwater moves?

1. Grain shape and packing

2. Grain-size distribution

3. Degree of compaction

4. Degree of cemenation

What are the inputs to a water system?

Precipitation and laterally moving groundwater

What are the outputs for a water system?

Evapotranspiration, surface runoff, and runoff through the ground

What inputs/outputs can be actually measured?

Precipitation and surface runoff