Ground Water

Note: Please refer to the GETTING STARTEDmodule to learn how to maneuver through and answer the lab questions using Google Earth ().

KEY TERMS

Students should know and understand these terms:

Aquifer

Dissolution

Stalactites

Cave

Groundwater

Stalagmites

Cavern

Karst landscape

Subsidence

Carbonate rock

Sinkhole

Tower karst

Disappearing stream

Speleothems

Water table

LAB LEARNING OBJECTIVES

After successfully completing this module, you should be able to the following tasks:

· Identify karst features on a topographic map and aerial photo

· Identify land uses associated with karst topography

· Identify components of the groundwater system

· Explain how water enters, flows through, and exits the ground

· Explain how caves and caverns are formed

· Explain how the hydrologic cycle functions

· Identify land uses associated with groundwater

INTRODUCTION

This module examines Karst landscapes and groundwater. Topics include caves, caverns, sinkholes, aquifers, infiltration and groundwater movement. While these topics may appear to be disparate, you will learn how they are inherently related. The modules start with four opening topics, or vignettes, which are found in the accompanying Google Earth file. These vignettes introduce basic concepts karst landscapes and groundwater. Some of the vignettes have animations, videos, or short articles that will provide another perspective or visual explanation for the topic at hand. After reading the vignette and associated links, answer the following questions. Please note that some links might take a while to download based on your Internet speed.

Expandthe INTRODUCTION folder and then select Topic 1: Introduction.

Read Topic 1:Introduction.

Question 1: What human disturbance is evident in both surface and subterranean karst environments?

A. Human dwellings

B. Pollution

C. Agricultural land use

D. Dams for hydroelectric power

Read Topic 2: Karst Landscapes.

Question 2: How are caves and caverns, once underground, now visible on the surface in mature tropical karst environment?

A. A decrease in water levels exposed the caves and caverns

B. Terracing of mountains for agricultural production exposed them

C. Tectonic uplift and weathering and erosion of mountains exposed them

D. Removal of vegetation exposed the caves and caverns

Read Topic 3: Groundwater

Question 3: How does the “ground” (soil, rock, topography) influence groundwater movement? (Check all that apply).

A. The ground can temporarily hold or store the water

B. Groundwater generally conforms to the topography of landscape

C. Soil type affects infiltration rates

D. The ground does not influence groundwater movement

Read Topic 4: Human Interaction.

Question 4: According to the website, what are three methods used to mitigate subsidence? (Check all that apply).

A. Repressuring of wells through aquifers

B. Artificial recharge of aquifers from the land surface

C. Reduction of pumping draft

D. Repressuring of aquifers through wells

Collapse and uncheck INTRODUCTION.

For the rest of this module, you will identify and explain the geographic distribution, patterns, and processes associated with karst processes and groundwater. In doing so, you will recognize and appreciate the impact that these processes and features have on the surface.

GLOBAL PERSPECTIVE

Double-click GLOBAL PERSPECTIVE, and the select Global Karst Distribution.

Karst environments are found throughout the world, and are found in nearly all climates and locations on earth. Many metropolitan cities are found in these karst landscapes. Moreover, many of these cities also are situated above or near large aquifers that provide water (in the form of groundwater) to the city and surrounding areas.

For Questions 5 to 8, double‑click and check each question to arrive at the city located in a karst environment. To find the associated large aquifer system located beneath or adjacent to the city of interest, select Global Aquifer Distribution and click global map. Fill in the blanks below with the answer:

City

Associated Aquifer

Question 5

A. Miami

B. Tampa

C. Cairo

D. Paris

A. Gulf Coastal Plains

B. Eastern European

C. Central Asian

D. Western Desert

Question 6

A. Moscow

B. Paris

C. London

D. New York

A. Gulf Coastal Plains

B. Eastern European

C. Central Asian

D. Western Desert

Question 7

A. Cairo

B. Dubai

C. Johannesburg

D. Nairobi

A. Eastern Africa

B. Sahara Basin

C. South Africa

D. Karoo Basin

Question 8

A. Paris

B. Bonn

C. Rome

D. Madrid

A. Southern Europe

B. Germanic Basin

C. Parisian Basin

D. Alpine Aquifer

Collapse and uncheck GLOBAL PERSPECTIVE.

KARST TOPOGRAPHY

Expand the KARST TOPOGRAPHY folder, and then double‑click and select Dunnellon, Florida.

After the topographic map displays in Google Earth, expand the Feature A folder, and then select both Feature A and Feature A Profile.
Note: You might have to zoom out to clearly see Feature A.

Notice that the contour lines are enclosed and hachured.

Question 9: What do enclosed hachured contour lines topographically represent?

A. Water body

B. Hill top or high point

C. Depression

D. Unsure about exact location of contour

Question 10: What do enclosed contour lines without hachured lines topographically represent?

A. Water body

B. Hill top or high point

C. Depression

D. Unsure about exact location of contour

Question 11: What type of karst landform is Feature A?

A. Sinkhole

B. Cave

C. Cavern

D. Tower Karst

Right click the term Feature A Profile and select Show Elevation Profile

Question 12: What is the relief (difference in elevation between maximum elevation and minimum elevation) within Feature A using the elevation profile (in feet)? (Select the answer closest to what you see in your elevation profile window).

A. 70 feet

B. 1,393 feet

C. 900 feet

D. 9 feet

Uncheck the folder Feature A. Verify Dunnellon, Florida is still enabled, and then double‑click and select Feature B.

Question 13: Why would these features have to be on the surface?

A. Ground is too soft to construct them underground

B. Ground is too wet to construct them underground

C. Risk of wastewater contaminating groundwater

D. Risk of groundwater contaminating wastewater

Uncheck Feature B. Verify Dunnellon, Florida is still enabled, and then double‑click and select Feature C.

Question 14: What is this feature?

A. A lake

B. A pond

C. A spring

D. A swamp

Uncheck Feature C. Verify Dunnellon, Florida is still enabled, and then double‑click and select Feature D.

Question 15: What is this feature?

A. Stream

B. Road

C. Trail

D. River

Uncheck Feature D. Double‑click and select Feature E. Notice what the feature looks like in the Topographic map.

Uncheck the Dunnellon, Florida topographic map. Use the Historical Imagery option to set the date to 1/5/1999. Compare the water in the feature in 1999 to the water feature on 1/17/2010.

Question 16: What has happened to the water level in Feature D?

A. The water level has increased

B. The water level has decreased

C. The water level has remained the same

D. Unable to determine

Uncheck Dunnellon, Florida.

Now we will go to Mt. Gambier, Australia.

Double‑click and select Umpherston Sinkhole. Click the link on the call out box for Umpherston Sinkhole and watch the short video clip.