Peak discharge values may be qualified using the following codes:
| Code | Description |
|---|---|
| 1 | The discharge is a maximum daily average. |
| 2 | The discharge is an estimate. |
| 3 | The discharge was affected by a dam failure. |
| 4 | The discharge is less than the indicated value, which is the minimum recordable discharge at this site. |
| 5 | The discharge was affected to an unknown degree by regulation or diversion. |
| 6 | The discharge was affected by regulation or diversion. |
| 7 | The discharge is an historical peak. |
| 8 | The discharge is actually greater than the indicated value. |
| 9 | The discharge was due to snowmelt, hurricane, ice-jam or debris dam breakup. |
| A | The year of occurrence is unknown or not exact. |
| B | The month or day of occurrence is unknown or not exact. |
| C | All or part of the record was affected by urbanization, mining, agricultural changes, channelization or others. |
| D | The base discharge was changed during the year. |
| E | Only the annual maximum peak was available for this year. |
| blank | No remark. |
Notes: