18 Fatal Flood

We will watch together in class the video Fatal Flood^[1], a documentary about the 1927 Mississippi River flood that was the worst in the nation’s history, transforming both culture and politics. Echoes of the flood reverberated across the U.S. and into its future, including through the time of Hurricane Katrina.

This is one of my favorite videos. It combines geology with soci-ology, history, and political science—an integration that is central to the thrust of this course. Most of you are not science majors, nor are you likely to take a science course after this one. Beginning to see the connection of science to many other areas of life is a significant thrust of the course. Be sure and take a look at the review questions related to the video.

Notes on Rivers and Flooding

• It is normal for rivers to flood. Most natural streams flood every one of two years, at least topping their banks.

• When a stream tops its banks, the coarsest material drops out first, the coarse material forming a natural levee.

• Further away from the stream, the amount of sediment decreases, as does the elevation. From the natural levee, the landscape becomes swamp (with trees) and then marsh. The marsh has little sediment, with mostly organic material.

• The area away from the stream where water from floods often flows is called the flood plain. It is a natural storage area for flood waters, but the flooding also creates rich agricultural lands. It’s no accident that many of the worlds first civilizations forms on deltas, discussed later in the Geology and Jazz section.