The current Upper Mississippi River and Illinois River flow frequency study, completed in 2004, was created using a period of record ending in 1998. Since then frequent and record setting major floods have occurred. The flood of 2019 was not only historic with regards to flood heights, but also in its duration. The Mississippi River was above flood stage at Cape Girardeau for 145 days. In addition, many communities between Dubuque, Iowa and St. Louis, Missouri have experienced the majority of their top 10 flood crests in the past 20 years. Significant flooding on the UMR occurred in 2001, 2008, 2011, 2013, 2014, 2018, and 2019. The Illinois River has experienced the same unprecedented flooding. At Peoria, IL (on the IWW), 5 of the 10 highest flood crests have occurred since 1998; including the record crest in 2013.