HURRICANE KATRINA – USING A STREAM TABLE TO INVESTIGATE THE ROLE OF LEVEE BASE WIDTH ON FAILURE TIME DURING FLOODS

2005 was a record year for hurricanes in the United States. Hurricane Katrina, one of the most significant storms of the year, formed the basis of my research project for 7th grade Earth science class. Some 350 miles of levees surround New Orleans and hold back the waters of the Mississippi River and Lake Ponchartrain. Portions of New Orleans are more than 15 feet below sea level, making it easier to flood and harder to drain floodwaters. During Katrina, several levees failed, sending billions of gallons of water into New Orleans and causing the city to fill like a bath tub. A controlled experiment was designed to test the relationship between the width of the levee base and the likelihood of failure. The problem relates to the flooding of New Orleans because maybe if the levee bases were thicker, they might not have failed. Levees of 1-, 2-, and 3-inch thickness were constructed from sand within a slightly sloped stream table. Levees were arranged so that they thinned downslope on one side of the channel and thickened downslope on the other side. Water was poured into the upper end of the stream table and the process of levee erosion (failure) was recorded in notes and photographs. The experiment revealed that the thinnest levee (1-inch wide base) failed first whether it was upslope or downslope; however, although the three inch levee failed last, one of the 2-inch thick levees did not fail at all. Further experiments are needed to understand why one of the two-inch wide levees did not fail. The process of investigating a major natural disaster through research and experiments revealed the importance of science and engineering to everyday life.