Lesson: Raging RiversContributed by: Integrated Teaching and Learning Program, College of Engineering, University of Colorado Boulder
Educational Standards :
Learning Objectives (Return to Contents)
After this lesson, students should be able to:
Introduction/Motivation (Return to Contents)
Who can tell me what a river is? Yes, a river is a part of the land that has water flowing in it at least some time of the year. Land, called banks, surrounds each side of a river. We also call this area the riparian zone, which just means the land on either side of the river. Who has ever seen a river? Is there one near our school or your home? What might be found in the riparian area of the river? (Possible answers: Plants, animals, insects, sand, gravel, bike path, bridge, sidewalks, etc.) For what purpose might we use a river? (Accept all reasonable answers, which might include: fishing, transportation, swimming, kayaking, drinking water, watering plants and gardens, transportation, etc.) Today we are going to learn about rivers and the water cycle.
Let's start by learning about the different parts of the water cycle, as illustrated in Figure 1. (Make the attached graphic of the water cycle into an overhead transparency to show students.)
In this drawing, we see that water is always moving around in a circular pattern. Let's start with the ocean. Where does water from the ocean go? It moves up into the air and turns into clouds. This is called evaporation. Does anyone know why the water evaporates from the ocean? Well, the sun heats up the water, and some of the water on the surface of the ocean turns into a gas that rises and forms clouds. Next, what happens to water in the clouds? Correct! When there is enough water built up in the clouds, it snows or rains back onto the Earth's surface. This is called precipitation. That rain and snow can fall into rivers, lakes and oceans, or soak into the ground.
Close your eyes and think about when it rains on the school grounds. What happens to the water if it rains onto a grassy area? Right, the rain water soaks into the ground and plant roots "drink" the water. What happens if it rains onto the sidewalk or parking lot? Correct again! The rain water collects in puddles or runs off of the sidewalk into the grass or the street. Have you ever seen a really large puddle on the sidewalk or road where the rain has nowhere to go? Sometimes these puddles are so big that they make it hard to get to the other side (of the puddle, or the sidewalk!). Open your eyes.
Let's look back at the water cycle graphic, and think about rain on the sidewalk again. Do you think that making a lot of sidewalks and roads changes where the water goes when it rains or snows? Yes, it does. When we make more pavement than grassy areas, then the water has fewer places to absorb into the ground. It may just form those large puddles or turn nearby dirt areas into mud. If there is a river or creek between two sidewalks, then most of the water might run into the river. Sometimes this causes flooding of the river when an abundant amount of water overflows the banks. Also, any dirt or garbage on the sidewalk gets carried into the river along with the rainwater and pollutes the river.
Engineers help design communities, including the sidewalks, lighting systems, roadways and buildings. It is the job of these engineers to make sure that they design ways for rainwater to move throughout the community without causing flooding that might harm the people living there.To help with this, engineers design storm drains into sidewalks or roads so that the rain has a place to go. Sometimes they design grassy areas next to sidewalks and roads to give the rain water places to go. Engineers might also design walls (barriers) on the sides of rivers to prevent flooding onto a road. Next time you are walking or driving around your community, see if you can find the paths that engineers have designed to keep the rainwater from forming puddles or floods. Is it working?
Engineers also know that rivers can be a good resource for humans for drinking water and recreation, like swimming and fishing. To keep a river healthy, environmental engineers monitor its water quality in order to help prevent pollution so that it remains a healthy ecosystem and continues to be a safe resource for people. These engineers take measurements of chemicals to monitor its health, and they consider how different uses of the river, such as fishing and swimming, might affect the fish and plants that live in the river.
Lesson Background & Concepts for Teachers (Return to Contents)
Our Earth is covered by three types of land cover, either natural or human-made:
Permeable: This type of land cover easily soaks up excess water. Example: Land with native plants growing on it. This type of land usually has not been compacted by human activities.
Semi-permeable: This land cover can soak up some water, but not as much as permeable surfaces. Examples: Farmland, soccer fields and lawns.
Impermeable: This type of land cover does not soak up much water. Examples: Concrete sidewalks, asphalt roads, roofs, rock, stone.
Other Applications of the Water Cycle
The water cycle is also important to our fresh water supply used for drinking water, growing crops and industrial production. Since humans cannot drink the salty water from the oceans, we rely on freshwater from lakes, river and aquifers (underground reservoirs) to meet our needs for fresh water. When engineers alter the land by developing communities and roads, it changes the water cycle. For example, many problems with flooding in Chicago are due to the existence of so many paved areas. Originally, Chicago was built on marshy soil that absorbed significant amounts of water. Now, the heavy amount of water runoff during big storms has no place to go since pavement cannot absorb moisture. The water runs off the impermeable surfaces and into the local rivers, bringing them to dangerous near-flood levels. Engineers had the design challenge to build large underground storage tanks to hold storm water that can be used during storm-free times. Sometimes these tanks cannot hold the massive amount of water that flows as the result of a storm, so engineers in Chicago have suggested other alternatives to handle storm water runoff, including rooftop gardens, permeable alleys, green infrastructure, downspouts (which reduce the flow of water into the storm sewers), and rain gardens.
Engineers consider constraints (limitations) when building a community. These constraints might include the material and time requirements of building up the community, as well as the social, ethical and environmental considerations that are imposed by the building up of the community. As with most large projects, knowledge comes with experience. Engineers building up the community of Chicago did not have the experience they have now in knowing the effects of large communities of paved areas (which leave little land exposed to soak up rainwater). If those engineers had known then that this would become a problem, they might have planned scattered parks and areas with permeable surfaces to "soak up" the storm water. However, since the city was already designed and built as it is today, engineers are working to improve that situation by designing and maintaining a very expensive system for managing storm water underground to prevent floods.
Vocabulary/Definitions (Return to Contents)
Associated Activities (Return to Contents)
Lesson Closure (Return to Contents)
Today we have been talking about rivers and the water cycle. Can anyone tell me what a river is? Right, it is a landform that has water in it at least some of the year. Can anyone name a river in our area? Good, these are all rivers near where we live. Thinking about those rivers, what do we find along the sides of them, or what do you see in the riparian area? Right, we might find plants, animals or a bike path. So, for what purpose might we use a river? People use rivers for recreation (swimming, fishing, etc.), to irrigate farms to grow food, and even for transportation in areas where waterways are a good way to move about. Engineers also know that rivers are a good resource. They design ways for us to keep rivers clean to use for drinking water and other purposes. Engineers also know about the water cycle and its importance in the movement and use of water.
What is the water cycle? It is how water moves around the Earth. What are the processes that make the water cycle work? Part of the water cycle is evaporation and another part is precipitation. Precipitation includes rain and snow, which can soak into the ground or puddle on the pavement. Engineers design ways for rainwater from a storm to move into storm sewers or the ground instead of flooding roads or communities.
Attachments (Return to Contents)
Assessment (Return to Contents)
Discussion Questions: Solicit, integrate and summarize student responses.
Idea Web: Ask students to develop an idea web around the water movement for their local environment. How much precipitation is there? Is most of the precipitation rain, snow or something else? Where does the precipitation go? Are there many paved areas? Are there any rivers? Are there examples of how engineers have designed paths for the rainwater to flow off the pavement and onto grassy areas or rivers?
Question/Answer: Ask students the following questions:
Lesson Summary Assessment
Water Cycle in Your Area: Have students draw a water cycle for the area around their school, showing how the water flows around the school. Have them draw arrows illustrating how the water evaporates from a river or puddles into the air, where it condenses and fall back on to the grassy and paved areas (as well as the school building, roof and gutters). Have them draw red boxes around problem areas near the school that get frequent puddles or muddy spots. Have them describe what they would do to help prevent the puddles or muddy areas.
Lesson Extension Activities (Return to Contents)
Take students to a nearby creek or river to show them a riparian area. Look to see if human structures, such as drainage pipes or bridges, exist in the floodplain. Have them note the types of animals, plants and insects that live in the areas around their homes and near the river. Have students think about how precipitation and evaporation might affect the river and its nearby plants and animals.
References (Return to Contents)
City of Chicago, Chicago's Water Agenda 2003. Accessed February 7, 2008. http://www.cityofchicago.org/city/en.html
Jones, Steve. Chicago Public Library, Down the Drain, "Five: Deep Tunnel," 2/2006. Accessed February 7, 2008. http://www.chipublib.org/
ContributorsKaelin Cawley, Malinda Schaefer Zarske, Janet Yowell
Copyright© 2008 by Regents of the University of Colorado.
Supporting Program (Return to Contents)Integrated Teaching and Learning Program, College of Engineering, University of Colorado Boulder
Acknowledgements (Return to Contents)
The contents of this digital library curriculum were developed under grants from the Fund for the Improvement of Postsecondary Education (FIPSE), U.S. Department of Education and the National Science Foundation (GK-12 grant no. 0338326). However, these contents do not necessarily represent the policies of the Department of Education or National Science Foundation, and you should not assume endorsement by the federal government.