To start, you may want to watch the What is Engineering video.
Too much rainfall or melting snow can sometimes cause a flood. There are different types of floods. The most common type is generally called a river flood. It occurs when a river or similar body of water (stream, creek, brook, etc.) overflows because of heavy rainfall and sometimes because of melting snow and ice. Other times, heavy rains are the result of hurricanes or other large storms.
Floods can be deadly and destructive to people and property. To prevent property destruction and injury to people, engineers study the dynamics of floodplains. They also work with geologists and meteorologists to devise ways to control flooding with a range of human-made structures: dams, dikes, levees, flood gates, seawalls, drainage canals, sewer/water/storm drainage systems, pumping stations, bridges, concrete river banks, spillways, overflow basins, embankments, retention ponds and wetlands restoration. To aid in prediction and planning, engineers and scientists also develop instruments and computer programs to monitor weather (precipitation, temperature, snow pack, etc.), and develop complex models to estimate worst-case-scenario storm surges and flood risks.
You can introduce the activity by showing students the PowerPoint presentation, Floods, Floodplains and Levees, to provide a visual understanding of floods, floodplains and levees. Or, print out some of the images to pass around class during the introductory discussion.
- Floods, Floodplains and Levees (PPT)
Students will learn more about flooding by creating their own mini-floods. Scientists and engineers do these same types of experiments with small-scale (models), as well as computer simulations, to understand how real-life floods behave. Ask students, “Does anyone know what a floodplain is?” It is the dry land surrounding a waterway, like a river or stream, into which flooding waters spill. An engineer needs to know the area of a floodplain in order to figure out how a flood might affect anything located there.
In this lesson, students act as engineers, buildingmini-houses (models) and determining if they get wiped out by the flood. This brings up an interesting point. If the human-made buildings were not there, would the flooding be a problem? Probably not. Natural flooding has been occurring for thousands of years. It only becomes a problem when people create something of value in the floodplain, like houses, that might be destroyed in a flood. As it turns out, floodplains are very attractive locations to build towns and cities — until flooding occurs. Ask students,“Why do you think people build houses in floodplains?”Well, a floodplain is usually a flat area conveniently located near a river that can be used for transportationandrecreation, as well as agriculture, with the land usually good for growing crops because of the rich soil deposited by past floods.
Students will test a few different situations that cause flooding. Ask students, “What might cause a flood to happen?” For more information, please see the Asking Good Questions video below.
There are a few considerations. The most important one is how much water is in the area. The more water that is introduced into an area (through rain or melting snow), the more likely flooding is to occur. Another important factor is how much space there is for the water to flow or settle into. If the riverbed is constricted or blocked by something like a dam or levee, then the water must find someplace else to go. Since floodplains are large areas, the water can spread out all over the place. Another issue (that is not addressed by this activity) is how much water the ground can absorb. Have you ever noticed that water soaks into the ground after it rains and makes the ground soggy or muddy? This is because different soils absorb different amounts of water, which can affect the amount of flooding that results. We are not going to look at that in this lesson, because we are using modeling clay, which absorbs essentially no water.