And Len Small is not the only one. There are five levees alone in Alexander County, along the Mississippi, Ohio and Cache rivers, protecting agricultural land, towns and the city of Cairo. In Illinois, 576 levee systems line 1,951 miles of land and water, according to the National Levee Database. Four levees in Illinois are considered to be at high risk of inundation because of a breach or system failure, according to a study of upper Mississippi River levees from the Environmental Law & Policy Center, placing more than 150,000 people and $16.9 billion of property in danger.