By completing this lesson, the learner will:
Exploration
Begin by giving students a stack of old magazines. Ask the students to create a class mural of pictures from those magazines which shows uses of water. List these uses beside the mural. Include: drinking, cooking, farming, energy, transportation, recreation, etc. Students should conclude that water is used in many ways by humans, and that many of these uses are life-sustaining.
Using Internet and/or other maps, discuss the where towns and cities in your home state are located. Focus on cities or towns established during early settlement and ask students to observe the geographical features of each site. In general, most settlements were established near a natural water source, as this was a critical geographical feature. Discuss the importance of water to early settlers and their needs. How important was water to farming, milling, commerce and other endeavors of early settlers?
Ask students to consider the concept of water rights. If an area has a limited amount of available water and an increasing demand for it, how could this situation affect relationships with neighbors and businesses upstream and downstream? Advise students that water rights played an important part in the history of certain geographical areas in the westward expansion of the United States.
Conclude that the more clean, usable water that can be made available in a geographic area for human usage and commerce, the better that region will thrive. Although some areas will have an abundance of water, contamination could render a supply unusable and other sources would have to be discovered. As students move through the activities in this lesson they should have a better understanding of fresh water resources.
Concept Introduction
Activity 1:
Much of the freshwater that is used by humans is found not on the surface of the planet but beneath it, in layers under the ground. This groundwater collects in aquifers at various depths, depending on the stratography of a specific region. To develop a better understanding of these layers, below are some links actual data from several Montana water wells. (Teachers may be able to find and use data from local wells in place of what is given below.)
Wolf Point: located in northeastern Montana, next to the Missouri River.
Bridger Bowl: near Bozeman, Montana, contains the highest elevation wells, at 6400 feet. Located in southwestern Montana.
Broadus: a flat plains area, elevation 3020 feet, located in southeastern Montana.
East Glacier Park: elevation 4780 feet, located in northwestern Montana.
Find the location of the wells on Montana state map. (Other state relief maps can be found here.) Discuss landforms at the well sites.
Using the information, construct a scale model of the layers of earth found while digging the well. Layers of construction paper can be cut and placed on a large sheet of butcher paper representing the total depth. Attention should be given to scaling the layers appropriately. Label each layer. Mark the level where water is found.
Direct students to use 1/4 inch graph paper to draw a representation of earthen layers according to water well data. (Choose an appropriate scale for each 1/4 inch block to represent. For example, each 1/4 inch block could equal one foot, two feet, ten feet, etc., depending upon the depth of the well.) Color and label each layer appropriately and indicate the level at which water is found. Compare graph paper models for different sites. Lead a discussion concerning similarities and differences between wells.
Lead the students in a discussion of soil types at each level. What factors might explain where the water is found? What layer is directly above and below the water level of each well? Are there any similarities? What conclusions can be made?
Using a flat-sided fish bowl, construct a layered model of the earth’s crust. Layers should include clay, sand, pebbles and rock, in an effort to duplicate on a simplified scale one of the water wells. Based on what was learned in Activity 1, predict at what level water will stabilize. Pour water into the bowl. Was the prediction correct?
Activity 2:
In order to demonstrate the process of accessing underground sources of water, set up the following experiment:
Place a bucket of water on the floor and a pan on the table above the bucket (see picture). Ask students how they might get the water from the bucket into the pan without picking up the bucket (groundwater). Provide them with string, a pipe and some pieces of cloth. Let them experiment for awhile.
After a while, show them the solution: Tie the string so that it forms a large circle that goes through the pipe. Tie some pieces of cloth onto the string. Use the string to pull the water up through the pipe so that it falls into the pan on the table.
Ask students to consider practical applications of this experiment. How do real wells compare to our simulated one?
Activity 3:
This activity accesses the USGS National Water Conditions Streamflow site to explore and interact with data produced at actual stream sites throughout the United States. First, in order to understand streamflow, create a simulated stream in the schoolyard with a hose and a ten foot section of aluminum house guttering. If an actual stream is located close to the school, a walking field trip to the site would be preferable.
Set up the simulated stream by allowing the hose to pour into the gutter. Use a ping pong ball as a float. Streamflow is measured in cubic feet per second (cf/s). Release the ball at one end of the pipe (with the water flowing) and time how long it takes to float to the other end of the gutter. Determine the velocity the ball moves (v= feet per second), then multiply by the cross-sectional area of the stream or simulated stream to get cubic feet per second.
Vary the speed at which the water flows through the gutter by increasing or decreasing the water pressure through the hose. How is streamflow affected?
If an actual stream is available, play a game of “Pooh Sticks.” Winnie the Pooh and Piglet often played this game by dropping sticks off a bridge over a creek. The stick that made it to the other side of the bridge first would win. Vary this game by creating a starting and finishing line. Have students find or make custom sticks and race them. Discuss the differences in currents and stream conditions that would result in slightly different calculations for winning and losing sticks.
After a firm understanding of streamflow is established, access the USGS Streamflow site. Select your state and the stream closest to your location. Note that data for each site includes longitude, latitude, location, drainage area, period of record, maximum, minimum, median and actual streamflow information. Record the information. Below is one example of station data:
Site #06043500 Gallatin River, near Gallatin Gateway - located 7.4 miles south of Gallatin Gateway at river mile 47.7. Latitude: 45 29'51" Longitude: 111 16' 11". Drainage area: 825 miles. Period of record - 67 years.
Conditions on 8/07/97:
Flow: 1,060 cu.ft/sec
Stage: 2.3
Data from the website: (click on thumbnail picture to see larger image)
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This site provides raw data as well as these graphs. Using the data, students can use a spreadsheet to draw their own graphs. View and discuss these graphs. Are there any trends evident? What would cause the high and low points? Are there any seasonal variations? How would precipitation affect streamflow?
Extract the data for other groundwater stations near the first selected site. Locate each site on a regional map and note the geographic features near each site. Discuss climate, landforms and landuse of surrounding regions for each site. Compare data for multiple sites and note any correlations. Are there any similarities? What might cause any differences?
Students should hypothesize about a relationship between precipitation and streamflow. Is there a correlation? Positive, negative or none? Discuss the possibilities. If a correlation is suspected, would precipitation have an immediate or delayed effect on streamflow? How could we find out? Using internet resources, locate precipitation data for monthly time intervals which correlate to the streamflow data. Create a corresponding graph with this data and overlay it with the streamflow graph. You should be able to see a relationship between precipitation and streamflow. There will be a time lag which decreases with urbanization of the area nearby the stream.
Note the periods of low precipitation. The stream still flows even when there is no rainfall. Where does the stream get its water during these periods? The water in the creek when there is no incoming precipitation is groundwater. This is referred to as “base flow.” The source of this water is the underground water coming to the surface that they worked with in the first activity.
Concept Application
For the purpose of this activity, assume your students are the staff members of the Land Use and Resource Management Department of a local county. A new factory is considering relocating to your area and has applied for a permit to dig a well for a freshwater supply.
Debate the advantages, disadvantages and problems that will arise should the permit be issued. How will this new well effect locations downstream? How will landowners, residents and businesses be affected? Should the permit be issued or not? What factors could influence your decision? How has what we have learned about groundwater and streamflow helped in understanding the cause and effect relationship of supply and demand of natural resources?
After exploring streamflow and water use issues in their local area, ask students to develop a water use plan. Look at local climate data for your region. How would local preciptation patterns affect a water use plan?
