Qualification Codes for Peak Flow Data

C1 = Crest information looks unreliable and incomplete and not used in frequency calculations. Some of the floods are based on current flood stage and nearby gage information.

C2 = Crest information looks reliable despite potential problems. This data was used in frequency calculations.

C3 = Crest height estimated by the USGS..

C4 = Crest height is from the National Weather Service.

C5 = Crest height affected by backwater.

C6 =Crest occurred at a previous flood stage that is lower than the current flood stage. The crests below the new flood stage are not used in flood frequency calculations.

C7 = rest from USGS yearly peak and/or date is different than the crest we provide. In many cases MARFC uses crest based on backwater or ice effects.

C8 = Crest month or day of occurrence has been estimated by The Middle Atlantic River Forecast Center usually based on nearby gage information.

C9 = Crest date (day) in the month is unknown.

F1 = Flow is an estimate.

F2 = Flow affected by regulation or diversion and in some cases to an unknown degree.

F3 = Flow effected by snow-melt, ice jam or debris jam break up.

F4 = Flow affected by dam failure.

F5 = Flow - All or part of the record affected by urbanization, mining, agricultural changes, channelization or other factors.

G1 = Gage height at a different site and/or datum.

G2 = Gage is not an official USGS gage with crests provided by the NWS. Crest information looks unreliable and incomplete and not used in flood frequency calculations.

G3 = Gage datum changed during this year.

none = No Code

 

 

Data provided by the U.S. Geological Survey

Additional support for this project was provided by the Susquehanna River Basin Commission, National Weather Service and Penn State University (PSU) Department of Meteorology. Special thanks to Michael Kozar (PSU student) for writing numerous weather summaries in the Floods by Events section.

Questions should be directed to Charles Chillag or Alaina MacFarlane.