Flood Control Engineering

Students apply their knowledge of the water cycle, weather, and climate to evaluate how some weather events can impact humans. They evaluate possible solutions that people can design to protect against flooding, specifically the use of levees along riverbanks to protect floodplains.

• Rivers are a source of freshwater and they are part of the water cycle. During certain weather conditions, such as heavy rains, rivers can flood the land.
• Floods are events that occur when water overflows onto land that is normally dry.
• Engineers can use the science of rivers and the water cycle to design solutions to flooding.
• Using an engineering process gives engineers a logical set of steps to help them move from the problem they are trying to solve to the solution.
• Engineers design different dams and levees to reduce the effects of flooding.
  
  

• Why are rivers part of the water cycle? What causes rivers to flood?
• Why does water on Earth’s surface flow downhill?
• Why does weathering and erosion result in natural levees?
• How does flooding affect people?
• Why is it important for engineers to build prototypes before large-scale technology? Why is it important for engineers to test their prototypes?
• How is a dam different from a levee?
• Why do people build levees and/or dams along rivers? Why do levees sometimes cause problems?
• What are the risks of building a dam across a river?
• How might an engineer decide whether to design and build a levee or a dam to solve the problem of flooding?
  
  

Misconception: Water that evaporates has disappeared.

Fact: Matter never disappears. Evaporation refers to the process of liquid water turning into a gas. It is still present even though we cannot see it.

Misconception: Flooding is unusual.

Fact: Extreme flooding may occur only once in 100 or 1000 years. It is common for many bodies of water that are not human controlled to flood seasonally. 

Climate : the average weather over a span of 30 years

Dam : a special kind of wall that holds back water

Engineer : someone who uses scientific knowledge and mathematics to solve a problem by creating new technologies

Evaporation :the process of liquid water changing into water vapor, its gas state

Flood : an event that occurs when water overflows onto land that is normally dry

Floodplain : an area of land next to a stream or river that floods easily

Levee : a natural or human-made wall that helps to keep water from overflowing a river or other body of water

Precipitation : the process of water falling back to Earth in the form of rain, snow, sleet, or hail

Proportion : the relationship between things, as to size, quantity, or number

Prototype : the scaled-down version of a technology

System : a set of connected, interacting parts that form a more complex whole

Water Cycle : the circulation of water from a collection to the atmosphere and back to Earth in four steps: evaporation, condensation, precipitation, collection

Weather : the conditions of the atmosphere (temperature, humidity, wind speed, air pressure, and precipitation) in a particular place at a particular time

The Flood of 1927

In 1927, the Mississippi River flooded. A flood is an event that occurs when water overflows onto land that is normally dry. A floodplain is an area of land next to a stream or river that floods easily.

The flood of 1927 was the most destructive river flood in the history of the United States. This flood was caused by heavy rains. These rains caused the river to overflow into the surrounding land. Water rose 9 meters high (30 feet) in some areas.

The flood affected 10 states: Arkansas, Illinois, Kansas, Kentucky, Louisiana, Mississippi, Missouri, Oklahoma, Tennessee, and Texas.

Designing a Solution

After the flood, engineers came up with a solution to reduce the effects of flooding along the Mississippi. Engineering is different from science, although science and engineering are connected. Scientists use experiments to gain knowledge. Engineers use that scientific knowledge and mathematics to solve a problem by creating new technologies.

Just like scientists, engineers follow a process. Engineers often follow eight steps to guide them as they create new technologies to solve problems.

The engineering process begins with a problem. The problem that engineers were trying to solve was flooding that occurred along the Mississippi River when heavy rains fell. When engineers are defining a problem, they include the criteria. The criteria are the needs the solution must meet. They also include the constraints. Constraints are ways the solution is limited.

Once they have identified the problem, engineers need to research the problem. They want to find out what is known about the problem. For example, engineers need to know that floodplains flood easily.

They also need to know that as water moves over the ground, it pushes sediment to the side. This creates natural levees. A levee is a natural or human-made wall that helps to keep water from overflowing a river or other body of water. Levees are usually slightly higher than the river. They are also usually parallel to the way the river flows. Levees make the banks of the river higher so the river can hold more water.

A dam is another way to slow down the flow of a stream or a river. A dam is a special kind of wall that holds back water. Unlike a levee, dams block the flow of the water.

After engineers have researched their problem, they survey the available materials. This survey includes a sketch of the material. It also lists how much of the material they have available and the properties of that material. Engineers often use soil, sand, rocks, or concrete when designing solutions to flooding.

Engineers then come up with possible solutions for how the problem can be solved with the available materials. One solution to help prevent river flooding is to design a human-made levee. Another solution is to design a dam.

Engineers often consider more than one solution. They weigh the benefits and risks of each solution. They then decide on the solution that has the greatest benefit with the least risk.

In this lesson, students design a flood control method using levees to solve the problem of a river flooding during heavy rains. First, students create a scientific diagram of their prototype levee solutions. Then, they use their models as a guide for creating the model clay prototype levee solutions along a riverbed. Students collect and analyze data on the flooded area of their models with different prototype levee solutions.