| Flood Impacts |
| 27.9 | This is the RECORD FLOOD LEVEL that was reached on July 9 1993. |
| 27.0 | Water reaches the top of the lower gates. |
| 26.5 | This level is expected to be met or exceeded on average once every 500 years. |
| 25.0 | Major flooding begins. Flood water overtops the levee protecting the town of Canton. |
| 24.5 | This flood level was reached on April 24 1973. |
| 23.6 | This level is expected to be met or exceeded on average once every 100 years. |
| 22.2 | This level is expected to be met or exceeded on average once every 50 years. |
| 20.8 | This level is expected to be met or exceeded on average once every 25 years. |
| 20.0 | Moderate flooding begins. Flood waters reach the top of the upper gates. |
| 19.5 | Flood water reaches the top of lock guide wall. |
| 18.8 | This level is expected to be met or exceeded on average once every 10 years. |
| 17.3 | This level is expected to be met or exceeded on average once every 5 years. |
| 16.4 | Burlington Northern/Sante Fe railroad tracks begin to flood. |
| 14.4 | This level is expected to be met or exceeded on average once every 2 years. |
| 14.0 | Both banks begin to overflow. Minor damages begin. |
| 8.5 | The Corps will not allow the pool level to drop below 8.5 feet (higher flows below 100K). At low flows, they allow a 2-foot variation between 11.0 and 13.0 feet. At higher flows below 100K, the range is actually lower, between 8.5 and 10.5 feet. Above 100K cfs, the gates are raised above the water surface, allowing open river conditions. |
