| Flood Impacts |
| 32.2 | Flood of Record - July 13, 1993 |
| 30.8 | This level is expected to be met or exceeded on average once every 500 years. |
| 30.5 | This level is expected to be met or exceeded on average once every 200 years. |
| 28.9 | April 25, 1973 crest |
| 27.5 | This level is expected to be met or exceeded on average once every 100 years. |
| 25.7 | This level is expected to be met or exceeded on average once every 50 years. |
| 25.0 | Quincy Waterworks inundated. |
| 23.6 | This level is expected to be met or exceeded on average once every 25 years. |
| 23.0 | U.S. Highway 61 floods |
| 22.5 | Major flooding begins. |
| 22.0 | Major flooding begins. |
| 20.7 | This level is expected to be met or exceeded on average once every 10 years. |
| 18.5 | Urban damage begins in LaGrange, MO. |
| 18.1 | This level is expected to be met or exceeded on average once every 5 years. |
| 18.0 | Moderate flooding begins. |
| 17.0 | Flood Stage: Minor flooding begins. |
| 15.5 | This level is expected to be met or exceeded on average once every 2 years. |
| 14.0 | Unprotected bottomlands flood. |
| 12.3 | This is the upper limit of the pool level at Lock and Dam 21. |
| 12.2 | This is the target pool level for navigation at Lock & Dam 21. |
| 11.8 | This is the lower limit of the pool level at Lock & Dam 21. |
