lab 10 groundwate.f12

7/29/2019 Lab 10 Groundwate.F12

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Introductory Geology 101/103 team ________________________Fall 2012 names _____________________________________

_______________________________________________________________________________________________________________

LAB 10: GROUNDWATER PROCESSES AND WATER RESOURCESThe objectives of this lab are to:

Understand the relationship between sedimentary rock types and groundwater processes.

Construct and understand water-table topography. Determine the rate and direction of groundwatermovement.

Evaluate the hazards and risks associated with groundwater contamination.

PART I: THE TRAGEDY AT LOVECANAL, NY

Watch the video clip summary of the terrifying tragedy of Love Canal, Love Canal parts and 2(Modern Marvels Engineering Disasters). Part 1:http://www.youtube.com/watch?v=vKIM9sE0t6I&feature=related and Part 2http://www.youtube.com/watch?v=MXSE9kcBQCI&feature=related

After watching the video clip, discuss the landmark contamination case with your teammatesand answer the questions below. You may also refer to the website from the pre-lab to help

you with your investigation: History: Love Canal: the Start of a Movement:http://www.bu.edu/lovecanal/canal/index.html

1. How did the contamination get into the soil and groundwater at Love Canal?

2. What types of chemicals were in the soils?
http://www.youtube.com/watch?v=vKIM9sE0t6I&feature=relatedhttp://www.youtube.com/watch?v=vKIM9sE0t6I&feature=relatedhttp://www.youtube.com/watch?v=MXSE9kcBQCI&feature=relatedhttp://www.youtube.com/watch?v=MXSE9kcBQCI&feature=relatedhttp://www.bu.edu/lovecanal/canal/index.htmlhttp://www.bu.edu/lovecanal/canal/index.htmlhttp://www.bu.edu/lovecanal/canal/index.htmlhttp://www.youtube.com/watch?v=MXSE9kcBQCI&feature=relatedhttp://www.youtube.com/watch?v=vKIM9sE0t6I&feature=related


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3. What happened to the people who lived in or went to school at Love Canal?

4. What was the response of the government when they learned of the contamination and itseffects on the residents of Love Canal?

5. What is the relationship between Love Canal and Superfund?

6. What is the relationship between the residents of Black Creek Village and those of LoveCanal

7. Is the situation at Love Canal unique? What can be done to prevent this from happeningEVER again?

PART II: POROSITY AND PERMEABILITYReread sections 12.1 and 12.2, pages 280-283, in your lab manual. You will be conducting theexperiments in Exercise 12.1 on pages 282-283.

Observation Container A Container B Container C Container D

Grain Size

Sorting

Grain Shape

Porosity

Permeability

1. Before the experiments, in the table above, describe each material using qualitativeobservations (i.e. large or small grains; well or poorly sorted; rounded or angular; low-med-high porosity). Then, predict which material will have the greatest permeability. Which willbe the least permeable? Why did you make these predictions?

2. How did the results compare to your predictions? Was there anything surprising in theresults?


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PART III: SEDIMENTARY ROCKS AND AQUIFERSRocks: 13, 16, 19, 20, and 23

What types of earth materials are most likely to be contaminated by groundwater? Which onesare more likely to hold water and which materials are more likely to cause water to be repelled?The following section explores the different types of sediments and rocks that are affected by

groundwater processes.

An aquifer is an underground layer of water bearing rock, which transmits water to wells andsprings. Sediments and sedimentary rocks play a critical role in the groundwater story. Forsedimentary rocks to be good aquifers they must have high porosity and permeability.

Porosity is a measure of the void spaces in a material.

Permeability is the measure of the ability of a material to transmit fluids.Many sedimentary rocks consist of grains such as sand, silt or clay.

Aquifers: When sediment is deposited and lithified there may be spaces or poresbetween the grains. For example, sandstone is a sedimentary rock that often makes anexcellent aquifer. Limestone: While limestones do not have high porosity initially, theydissolve in slightly acidic groundwater so they also can make good aquifers.

Aquitards: Some sediment, such as clay, does not have much pore space when lithifiedto form shale. Shale is often an aquitard.

3. Test each rock specimen with HCl. Which specimen(s) reacted?_____________________________________________________________________

4. What is the significance in relation to groundwater systems of each of the rocks above? Inother words, how would an aquifer be affected if the bedrock consisted of #13 (sandstone)?

SpecimenNumber

Rock/Sediment Name Significance to groundwater systems

13

19

20

23

N/A SandExample: Uncemented sand is typically porous and permeable therefore

it would make a good aquifer.

N/A Clay

N/A Gravel


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PART IV: GROUNDWATER MODELINGTo enhance your understanding of groundwater, you will observe the movement of waterthrough different types of sediments in a groundwater model.

First, you will need to make sure the models are saturated with water.

Check with your instructor or TA to make sure the model is ready.

Second, you will place dye in one of the wells and watch how the dye moves through themodel.

The porosity and permeability of the different sediments will affect the direction and rateof groundwater movement.

a. Fill the plastic water bottles, insert stopper assembly, and invert it at the ends of thegroundwater model tank.

b. Allow the water to run through the groundwater model.c. Add dye to one of the monitoring wells. DO NOT PLACE DYE INTO THE SMALL

POND!! BE SURE TO ONLY PLACE DYE INTO ONE OF THE WELLS!d. Observe the direction and rate of groundwater movement as the dye flows through the

aquifer sediments. You can time the rate of groundwater movement either usingstopwatches, your watch, or your cell phone.

e. What direction does the groundwater flow - toward the lake or toward the river?________________

f. Why?

g. Use the box as the edge of the model andmake a sketch of the sediment layers in thegroundwater model. Label the types ofsediment and location of the river and wells.

h. Using the syringe, withdraw water from one ofthe wells, simulating pumping. Observe whathappens to the groundwater motion. Drawarrows on your sketch to illustrate.

i. What happened to the direction of the groundwater flow when you began pumping fromthe well?________________________________________________________________________

j. What happened to the direction of the groundwater flow when you STOPPED pumping?Why did this happen?________________________________________________________________________

k. Suppose a company that manufactures solvents dumped nasty chemicals into the groundin the middle of the night. What would happen to the farmers well water next door?________________________________________________________________________


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PART IV: GROUNDWATER CONTAMINATION

Section A: Rate of Contaminant Transport

In 1985, Voldemort Industries paint manufacturing company dumped chemical wastes(containing chromium, lead, and zinc compounds) from their paint pigment operations in alandfill near River Hogwarts (Figure 1). In response to concerns expressed by nearby residents,

Voldemort Industries conducted an investigation of the landfill in 2010 in which they installed thegroundwater monitoring wells T-1, T-2, T-3, and T-4. The 2010 water sample results from thesewells are listed below.

Well Number Depth to water table (m) Contaminants PresentT-1 11 NoneT-2 14 NoneT-3 17 Pb, Cr, ZnT-4 18 None

Well at Hagrids Residence 6 None Using the depth to water table for each well, draw the water table with a dashed line onFigure 1. Measure the depth to water from the top of the well - not from the ground surface Show the direction of groundwater flow with arrows on Figure 1. In 2010, the water sample from T-2 was not contaminated. When T-2 was sampled in 2011

it showed significant levels of lead, chromium, and zinc. Sketch the approximate boundariesof the contaminant plume (area of contaminated groundwater) on Figure 1.

8. How many years, since the chemical waste was dumped in the landfill, has it taken forthe contaminant plume to reach well T-2? Show your work!(HINT: when did contamination BEGIN?)

______ years

9. Approximately how fast is this plume moving (in m/year)? Measure the horizontaldistance from the middle of the landfill and well. Show your work!

_______ m/yr

10. In what year will the contamination reach the well at Hagrid s residence? Show yourwork!

___________

11. Why were no contaminants found in well T-4?______________________________________________________________________

12. Is the Dumbledore Formation likely to act as an AQUIFER or AQUITARD?

13. Will the plume contaminate the well water at Hogwarts? YES NO

14. Why or why not?______________________________________________________________________


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WEST EAST

Figure 1: Voldemort Industries Landfill Cross-section

Humphreys Shale

T - 1

T - 2T - 3

T - 4

Humphreys

Hermione FormationDumbledore Formation

Meters

VerticalScale

0

10

20

30

40

50

Sand and Gravel

Shale

Sandstone

Horizontal Scale

0 100 200

Landfill

Hagrids Residence

Hogwarts

River Hogwarts

Weasley Formation

Dumbledore FormationHermione Formation


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Section B: Exercise 12.7 Someone is Polluting My Water!

In this scenario, homeowners noticed a strange smell in whenever they took showers, washeddishes, or ran the tap for drinking water. Many complained of the water smelling and tastingsuspiciously of gasoline! Your Environmental Assessment company has been hired todetermine if there has been a gas leak from one of the nearby gas stations and if so, which oneis causing the contamination of the homeowners drinking water.

The background information in Section 12.4, 12.5, pages 288-290 and questions for thisscenario are found in Exercise 12.7 on pages 294-295 in your lab manual. Be sure to READthe exercise background before answering the questions!

You and your teammates will need to determine what you need to know in order to find asolution for these homeowners.

What information do you need to solve this case?

a. Does either gas station have a leakage problem? Explain

____________________________________________________________________________________________________________________________________________

b. Which homes or neighborhoods will be affected next? Indicate on the map below(Figure 12.13) where the gasoline contamination will go.

c. Gasoline concentrations of50 ppm and higher are considered dangerous. Circle thoselocations on Figure 12.13 below and color code the location (indicate your colorhere_________).

d. Are there other locations on this map that are likely to be in danger of contamination in

the future?

e. How do you know?______________________________________________________________________

f. If so, indicate those location on your map (Figure 12.13, page 295) with a different color note that color here ___________


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Figure 12.13

Contour Interval: 10 pp

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lab 10 groundwate.f12

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