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