Flood Walls or Wetlands for Flood Mitigation

The winter and spring of 2019 set several records in the Quad Cities, which is located in eastern Iowa. In January 2019 the Quad Cities saw 28.8” of snowfall, beating the previous record of 26.7” in January of 1979. On Thursday, May 2, 2019 the Mississippi River broke a record set back in 1993 for reaching its highest level ever recorded at 22.7 feet. Also in the Spring of 2019, the Mississippi River in the Quad Cities was above flood stage (18 feet) for 96 days in a row, crushing the previous record of 42 days set back in 1993. According to the Bettendorf Mayor Bob Gallagher, the reason for the flooding was due to the fact that between May 2018 - May 2019 the state of Iowa received more precipitation than has previously been recorded in the past 124 years of data. At the same time the global average temperature has increased by 2 degrees Fahrenheit, and more water vapor can be held in a warmer atmosphere. Furthermore, since 1979 the amount of Arctic sea ice at Earth’s North Pole has decreased by 3.3 million square kilometers, and it continues to decrease by 13% every decade. NASA predicts that as more ice turns to water and more water vapor is held in a warmer atmosphere, the Midwest can expect to see more flooding in the future.

With the expected increase in flooding in the future, cities across Iowa along major rivers must decide if they should invest a great deal of money in a flood wall or if they should open up land for wetland restoration. There are a pros and cons of each. Building a flood wall would almost guarantee the city protection from floods at a certain stage. Unfortunately flood walls block the view of rivers, could potentially fail in the future and cost a lot of money. Restoring wetlands allows for cities to keep the view of their river while storing millions of gallons of potential flood water so it doesn’t flood cities. Unfortunately this land could not be used to grow crops or build businesses and homes, and wetlands don’t offer the confidence of protecting the city from a specific river height.

• Should Davenport, Iowa, build a flood wall or should cities along the Mississippi add more wetlands to protect the Davenport from future flooding?

• Why does NASA suggest that all communities in the Midwest should brace for an increase in flooding events in the future?

Students could:

• Learn about the 2019 flood in Davenport and analyze whether a flood wall or wetland restoration is a better solution to preventing future floods.
• Construct an explanation for why cities and towns in other locations decided to build flood walls, or not build in certain locations due to natural hazards, or why certain cities are planning to bulldoze parts of their city and turn it into wetlands in those specific locations

• NPR | The Mississippi Has Been Flooding for 41 Days Now: This website contains an article from NPR documenting the devastating flooding that occurred in the Quad Cities in the Spring of 2019.
• NASA | Climate Change & Global Warming: This website from NASA contains data on Arctic sea ice melt, increasing carbon dioxide levels and global average temperature, as well as the effects these phenomena have on different parts of the country.
• EPA: Incorporating Wetland Restoration and Protection in Planning Documents: The EPA has put together guidelines for restoring wetlands in order to protect the community from flooding.