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Unearthing Groundwater:

GROUNDWATER & ARIZONA: Pre Lesson 1

Groundwater Use in the U.S.

The National Ground Water Association has determined that 38% of the U.S. population, depends on groundwater for its drinking water supply.

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How important is groundwater to Arizona?

GROUNDWATER & ARIZONA: Pre Lesson 1

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Let’s

Review!

Aquifer:

Groundwater moves between the spaces and pores and is pulled down due to gravity. The bigger the spaces between the materials, the faster or easier the water can move around it.

An area where significant groundwater is present. Groundwater flows between layers of earth materials.

Pore Spaces

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Well, well, well, what do we have here?

How do we access and use groundwater?

Both individual landowners and city municipalities drill wells to access groundwater.�

GROUNDWATER & ARIZONA: Pre Lesson 1

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How do we pump it up

and why?

GROUNDWATER & ARIZONA: Pre Lesson 1

We use it for drinking water, agriculture, and for pretty much everything else.

Do different places have different amounts of groundwater? Do you think it is evenly distributed under Arizona?

Just like surface water (lakes and rivers), our groundwater is not evenly distributed across the state…

There are many types of wells (some are observation wells so that we can see what is under our feet and some are pumping wells). Some are only 100s of feet deep while others can be 1,000s feet deep. But they all are expensive

A drilled well is constructed by a rotary drilling machine that literally “drills” a hole into the ground until it reaches the underground water source. These types of wells require a casing on the outside of the drilled hole as well as screening to prevent the driving water from being contaminated. The screen also reduces the amount of sediment flowing into the water storage tanks and can also improve the integrity of the well. These types of wells can reach depths up to 1,000 feet. Once the drilled well has been opened, a submersible water pump and piping system are installed and a casing cap is installed on top of the water wells, which also is designed to protect the integrity of the below-ground water source and reduce exposure to chemicals and other contaminants.

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Going, Going, Gone?

Decline & Depletion

What if we just keep pumping? Students will get to explore this when we come visit your school.

The water stored in the ground can be compared to money kept in a bank account. If you withdraw money at a faster rate than you deposit new money you will eventually start having account-supply problems. Pumping water out of the ground faster than it is replenished over the long-term causes similar problems. We call this overdraft

Pumping groundwater at a faster rate than it can be recharged can have some negative effects on the environment and the people who use that water:

LOWERING OF THE WATER TABLE – a severe consequence of excessive groundwater pumping is that the water table, below which the ground is saturated with water, can be lowered.

If groundwater levels decline too far, then shallow wells may dry up causing well owners to drill deeper (this is very expensive and not always possible.

We also know if we take too much groundwater it can reduce the amount of water in our streams, rivers and lakes.

We also call the area that lowers around the well that is pumping water, a cone of depression…

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Sink Holes, Fissures & Land Subsidence, Oh My!

So when we take too much groundwater besides drying up lakes and rivers, we can also cause damage to the land! ��This is a 2-mile-long crack that opened in the AZ desert in Pinal County between Casa Grande and Tucson because of groundwater pumping! The land subsided more in one area than in another, so it caused the earth to crack open. We call this a land fissure, and we have no idea if they can be repaired or how to repair them.

The bottom right picture is near Wilcox, AZ where the land has actually started to subside due to over pumping of groundwater. When land subsides, it loses its capacity to hold groundwater, as the spaces between the materials collapse and get smaller and smaller, so we can’t just pump water back into the ground to fix subsidence issues.

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Active Management Area and Irrigation Non-Expansion Area designations
Groundwater pumping limitations
Recharge

GROUNDWATER & ARIZONA: Pre Lesson 1

1980 Arizona Groundwater

Management Act

Because of over pumping and the issues we just discussed finally in 1980 The 1980 Arizona Groundwater Management Act (GMA) was passed.

The passing of the 1980 Groundwater Management Act (GMA) was monumental for many reasons. First and foremost, it established laws that enabled the State to manage and protect groundwater for the benefit of all residents across Arizona. It also created provisions to ensure this finite water source was preserved for the future.

It created Active Management Areas (AMAs), which introduced regulation and conservation measures in parts of the state with a history of heavy reliance on groundwater.

There are six AMAs in the state, Prescott, Phoenix, Pinal, Tucson, Santa Cruz and Douglas. Each has its own long-term goal in accordance with the Groundwater code

INAs – are Irrigation Non-expansion areas which prohibit the expansion of new irrigated acreage within established boundaries and require irrigators to report their water use if they pump more than 35 gallons per minute. There are 3 INAs.

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Recharging the Aquifer

GROUNDWATER & ARIZONA: Pre Lesson 1

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GROUNDWATER & ARIZONA: Pre Lesson 1

Watch Series of Arizona Groundwater Videos – an APW & ADWR joint project.

This Photo by Unknown Author is licensed under CC BY-NC

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A PLUME PROBLEM

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Investigative Questions

How does water move underground?
If groundwater is contaminated, will pollutants move to other nearby locations?

Groundwater & Sustainability : Lesson 1

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The Activity:

GROUNDWATER: A Plume Problem

Students read through a scenario and plot data on a map to discover groundwater contamination levels.
They soon learn that with new evidence their data may not lead to only one answer.

Sometimes past solutions become current problems.

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Now think about how this activity might play into the case file?

Provide Lead #1 & #2 after lesson:

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Wrap-Up

Stability &

Change

Lesson 1

What have you learned about how groundwater moves?

If it is contaminated, can pollutants move to other locations?
How does groundwater fit within the Arizona Water Cycle?

How can you protect and conserve groundwater?