Do you get the groundwater picture yet?. What is an “aquifer”?

Do you get the Do you get the groundwater groundwater picture yet?picture yet?

What is an “aquifer”?What is an “aquifer”?

An underground An underground formation that is capable formation that is capable

of storing AND of storing AND transmitting watertransmitting water

Some aquifers cover Some aquifers cover 100’s of square miles and 100’s of square miles and

be 100’s of square feet be 100’s of square feet thick. Others may only thick. Others may only

cover a few square miles cover a few square miles and be a few feet thick.and be a few feet thick.

Water quality and water Water quality and water quantity vary from quantity vary from

aquifer to aquifer, even aquifer to aquifer, even vary sometimes within vary sometimes within

the same aquifer! (how the same aquifer! (how can this happen?)can this happen?)

Some aquifers yield Some aquifers yield millions of gallons of millions of gallons of

water per day and water per day and maintain their water maintain their water

levels, while others may levels, while others may only be able to produce only be able to produce small amounts of water small amounts of water

each day.each day.

The rate of movement of The rate of movement of ground water varies ground water varies based on the rock based on the rock

material in the formation material in the formation through which the water through which the water is moving. After water is moving. After water percolates down to the percolates down to the water table, it becomes water table, it becomes

ground water & starts to ground water & starts to move slowly down move slowly down

gradient.gradient.

Water movement Water movement responds to differences responds to differences in energy levels. The in energy levels. The energies that cause energies that cause

ground water to flow are ground water to flow are expressed as expressed as

gravitational energy & gravitational energy & pressure energy (both pressure energy (both

are forms of are forms of mechanical mechanical energyenergy).).

Gravitational energy Gravitational energy comes from the comes from the

difference in elevation difference in elevation between the recharge between the recharge

area (where water enters area (where water enters the ground water the ground water

system) and discharge system) and discharge area (where water leaves area (where water leaves

the system).the system).

Pressure energy Pressure energy (hydraulic head) comes (hydraulic head) comes

from the weight of from the weight of overlying water and overlying water and

earth materials.earth materials.

Drilling wells is the best Drilling wells is the best way to way to get the ground get the ground

water picture!water picture!

You have a You have a well logwell log for for 25 different wells.25 different wells.

You are to illustrate your You are to illustrate your well data on a strip of well data on a strip of

paper.paper.

USE PENCIL FOR THISUSE PENCIL FOR THIS

Mark off 1” sections on Mark off 1” sections on your strip of paper.your strip of paper.

Using your well data, Using your well data, draw the boundary lines draw the boundary lines

for each substrate.for each substrate.Fill in the substrate Fill in the substrate

sections with the sections with the appropriate markings.appropriate markings.

We must all use the same We must all use the same colors:colors:

black line for the water black line for the water tabletable

yellow – fine sandyellow – fine sandorange- medium sandorange- medium sand

red – coarse sandred – coarse sandgreen – sandstonegreen – sandstone

clay- brownclay- browndark blue – graveldark blue – gravelpurple - granitepurple - granite

If the horizontal scale of the cross If the horizontal scale of the cross section is 1 inch = 1 mile, and the section is 1 inch = 1 mile, and the vertical scale is 1 inch = 50 feetvertical scale is 1 inch = 50 feet

How many miles are horizontally How many miles are horizontally represented in the cross section?represented in the cross section?

25 miles25 miles

How many feet are vertically How many feet are vertically represented in the cross section?represented in the cross section?

600 feet600 feet

How many feet below the surface is How many feet below the surface is the water table?the water table?

(yes, I know it varies, but from what (yes, I know it varies, but from what depth to what depth??????????????)depth to what depth??????????????)

12.5 to 250 feet12.5 to 250 feet

Imagine a drop of water falling on Imagine a drop of water falling on the surface near well #8. What type the surface near well #8. What type of pollutants might enter the of pollutants might enter the groundwater there?groundwater there?

Fertilizers, pesticides, tractor fuel Fertilizers, pesticides, tractor fuel and POO POO!!!!!!!!and POO POO!!!!!!!!

Through which layer(s) would a drop Through which layer(s) would a drop of water move the fastest?of water move the fastest?

GRAVELGRAVEL

Which layer would take the longest Which layer would take the longest for a drop of water to get through?for a drop of water to get through?

CLAYCLAY

Got a calculator? Get it out. If the Got a calculator? Get it out. If the groundwater has a flow rate of 100 groundwater has a flow rate of 100 feet per day, how long would it take feet per day, how long would it take the water in the sandstone formation the water in the sandstone formation to move from well #1 to well #15?to move from well #1 to well #15?

792 days or a bit over 2 years792 days or a bit over 2 years

How deep is the zone of aeration at How deep is the zone of aeration at well #11?well #11?

150 feet150 feet

How deep is the zone of saturation How deep is the zone of saturation at well #6?at well #6?

About 325 feetAbout 325 feet

Last question: Where would you Last question: Where would you label a “cone of depression” on the label a “cone of depression” on the class chart?class chart?

Between well #11 and well #19Between well #11 and well #19

Are you “water-logged” yet???Are you “water-logged” yet??? Get it? Ha, Ha, HaGet it? Ha, Ha, Ha