A Watershed In Action
National Park Service Mission
...to conserve the scenery and the natural and historic objects and the wild life therein and to provide for the enjoyment of the same in such manner and by such means as will leave them unimpaired for the enjoyment of future generations.
Black Canyon of the Gunnison National Park and Curecanti National Recreation Area Outreach Education is committed to: Creating an awareness and fostering an appreciation for the mission of the National Park Service and the natural, cultural, and historic resources of Curecanti National Recreation Area and Black Canyon of the Gunnison National Park.
EDUCATION LESSON PLAN
Title: A Watershed In Action
Grade level: Fifth grade
Theme: Studying the watershed we live in can help us understand the connection and responsibility that we have to the people and wildlife that live downstream.
Materials:Water trailer, rented through the Forest Service in Gunnison (641-0471); hose; water spigot at the school; electrical outlet; extension cord; plastic farm animals; rocks of a variety of sizes; plastic landscaping (should all be located in the storage area of the water trailer)
Comprehension level: Students will be able to list two ways that natural and made-made rivers differ.
Application: Students will be able to use the components of the water table to form either a natural or a man-made river.
II. ANTICIPATORY SET
III. TEACHING PROCEDURE/METHODOLOGY
“Today we are going to be talking about rivers and watersheds. What is a watershed? (take a few answers) A watershed is a region draining into a river, river system, or other body of water. We live in the Uncompaghre/Gunnison River watershed. Therefore, all the water that drains from the mountains in this area will flow into what river? The Uncompaghre/Gunnison River, very good.
We live west of the Continental Divide. That means that the water here is flowing in which direction, east or west? West. Near here (or downstream from here), past Blue Mesa there is a huge geological formation. Can anyone tell me what that is? The Black Canyon of the Gunnison. This huge canyon was carved out over millions of years by the Gunnison river that passes through town. After the 48 mile canyon, the Gunnison River winds to the north/northwest, joining the Uncompaghre River in what town? Delta. Jointly, these two rivers become the Gunnison River, and who can tell me which city they flow downstream into next? Does anybody know which large city in Western Colorado we’re talking about? Grand Junction, yes! Here, the Gunnison River empties into, or joins with, an even larger river, called….the Colorado River. From there, where does the Colorado River flow? It passes through Utah, through the Grand Canyon in Arizona, through Nevada, and eventually, California. Its ultimate destination is the Gulf of California, over a thousand miles away, in the ocean. Our Gunnison watershed connects us to all the other watersheds, people and wildlife downstream, emptying into the Gulf of California, if any water remains. Our actions here can affect many people and animals downstream.
Now that we’ve explored the Colorado River watershed, let’s talk about river processes. If your teacher gave you the choice of taking a test on your least favorite subject that had one question or 500 questions, which would you choose? Most of us would choose one question, because it’s easier. Do you think the river does the same thing, takes the easy route? Imagine that a river is flowing along right here. All of a sudden, a rockslide makes a huge boulder fall into the river’s path. Do you think that the river would stop, and start to slowly carve its way through the boulder, or would it simply flow right around it and continue downstream? It would go around it. Rivers take the route of least resistance. So does that mean that rivers could change over time? Yes. If you were to return to this area in 20 years, do you think the (Gunnison, Uncompahgre, etc.) River would be exactly where it is today? Probably not. Rivers and streams are constantly changing their courses. One of the most dramatic changes in a river might occur during the spring meltoff. Sometimes Colorado gets huge amounts of snow high in the mountains, and when all of it melts, it comes rushing down the mountains in small streams, and pours into the Gunnison Watershed, and the Gunnison River. Its banks may overflow, causing it to change its course.
One great example of this occurred in the spring of 1995. The winter before, it snowed a lot up in the mountains. When it melted, it caused a massive flood in the Gunnison River. In an area called Neversink (have any of you been there?) the river overflowed its banks and began to follow a new course. This caused some conflict. Neversink was a popular fishing spot. Fishermen enjoyed easy access to the river. After the flood, the river changed its course to a half a mile away from the road, meaning that the fishermen had to walk through a muddy area, over and under trees and bushes, to reach the river. They didn’t like this, so they asked the National Park Service to put the river back where it was before. Do you think we, the NPS rangers, did that? No, because our mission is to let nature take its course. The flood was a natural process, so we decided to let the river remain where its new course had taken it. The change in the river’s course actually made it a better environment for fisherman. The original path of the river became a slower moving channel, or a secondary channel, allowing for the growth of more macro invertebrates, which attract many trout. Does anyone know what macro invertebrates are? That’s right, small bugs and insects. So the change in the river’s location actually helped the fisherman.
Now that we’ve learned about some of the natural processes that impact a watershed, you will all have the very special opportunity to see a real-life demonstration of how rivers will change their course to find the path of least resistance. We have two rivers set up on our water trailer outside. One is a natural river and the other is a manmade river. We will set up different scenarios to see how the river erodes and evolves over time.
This water trailer is like a big sandbox, but it is important to remember that the sand is really expensive ground up soda bottles. I know it looks really fun to play in, but I am going to have to ask you to keep you hands out of the trailer and only watch, unless I ask you to help move something. If you do get the sand on your hands, please brush your hands off over the water trailer, instead of over the grass, because like I said, this sand is rather expensive.”
IV. CHECK FOR STUDENT UNDERSTANDING
V. GUIDED PRACTICE
(Before you turn the water on…) “In order to understand what’s happening on the water trailer, let’s look at some important words.” Show the children signs with vocabulary words on them, one at a time. Ask them to define each word. The student that defines it correctly gets to place the sign in an area that represents that word on the water trailer. There should be signs for riparian habitat (area along rivers or streams, lush vegetation), watershed (point out actual watershed boundaries on the horizon to students now that they are outside), structures (manmade house, barn, windmill), runoff, permeability (having pores or openings that permit liquids to pass through), sediment (small particles of sand, mud, clay, discuss how sediments travel in rivers as they are suspended, but they settle down when the river slows, which is usually at the end of the river or on the inside corner of bends in the river), erosion, gradient (the steepness of a river; use this term as a segue to discuss the other factors that determine the speed and strength of a river, such as depth, width, path of the river, composition of river bed), delta (where the sediment gets deposited as the river slows down, such as the Mississippi delta), meander (noun and a verb, means a curve or to wander back and forth), etc.
Which river do you think is natural, and which one has been altered by people? What clues tell you that one is natural and the other has been altered? (riparian vegetation along the natural river, rocks along the other; houses along human-altered river; natural river meanders, altered river is straighter).
Before we turn the water on, tell me what you think is going to happen. Let’s form some hypotheses, or educated guesses. Which section of the river will erode the most? Will one river erode more than the other? Which river will flow faster? Why?
“Are you ready to see the rivers in action? First, we’re going to look at the human altered river. These people have built a house and a farm right along the river. They even have an irrigation system set up to water their fields. The biggest alteration by humans seen here are the rocks these people have put along the edge of the river bank to help prevent erosion. You can see the water being diverted through the irrigation tunnel and it’s beginning to water the field. Can you start to see erosion anywhere? These rocks are helping to protect the house, but some erosion is still happening. What is forming at the end of the river? That’s right; it’s the formation of a delta. Now let’s see what would happen if these people didn’t put these rocks here. (Remove rocks) See how the river is starting to carve out the edges on the outside of the river bends and depositing sand on the inside of the river bends? What do you think is going to happen eventually as this process continues? The bends will get bigger and the river course will start to meander more.
What is preventing erosion in this riparian area? That’s right, the lush vegetation has roots that penetrate into the soil, holding the soil in place. The vegetation provides the same protection that the rocks did in the human altered river. What’s going to happen when I pull the vegetation out? It will start eroding. Now in this curve in the river, which part of the water is moving faster and which side is moving slower? Yes, the outside edge of the river is moving faster and the inside is moving slower. Do you think erosion will take place faster on the outer or inner bend of the river? On the outer bend, where the water travels faster. On the inner bend, the sediment will settle to the bottom, since the water travels more slowly there. This causes the river to meander as time passes.
Let’s talk about this parking lot. Are parking lots clean areas? No, often times cars drip oil and chemicals onto the asphalt, and garbage ends up in parking areas, too. Is this parking lot permeable? No. If it were to rain here, what would happen to the water, the oil, chemicals, and garbage? Would they sink into the concrete? Let’s do an experiment to see if we’re right. (Pour watering can over the parking area/upside down mouse pad, which is positioned on top of a hill. The water should flow down, off the area, and eventually into the rivers.) All of these contaminants would run off, into the rivers.
“Let’s take another look at our human river. Look at the house. It has collapsed into the river now that the rocks are gone, because erosion has caused the river bed to widen so much. How do you think this family could have prevented this erosion? They could have planted native plants with strong roots, which would have held the soil in place.
“Does all the water of the Gunnison River ever make it to the Gulf of California? No, that’s right. What do we use the water for? Drinking, irrigation, cooking, showers, flushing the toilet, watering lawns, fighting fires, and it is used in industry as well, when water is diverted to cool down the equipment. We also use water to create electricity by placing dams along a river. This is called hydroelectricity, or electricity formed by the force of water. Does hydroelectricity waste any water? No, after the water is used to create hydroelectricity, it is released back into the river. But not all of the water makes it down to the Gulf of California.
VI. INDEPENDENT PRACTICE
Did You Know?
Bald Eagles winter at Curecanti, feeding on fish until the water becomes ice covered.