Potomac River at Hancock, Washington County MD (HNKM2)
Gage Location: Washington County, MarylandSite Location: Washington County, Maryland
Latitude: 39.698Longitude: -78.178Elevation: 383.68 ft. MSLDrainage Area: 4064 Sq. Mi.
Minor Stage: 30 ft. Moderate Stage: 33 ft.Major Stage: 35 ft.
First Flood: 1889-06-01Last Flood: 1996-09-08 Crest: 35.81 ft.Datum change: 1937-01-21Number of Floods: 13

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Date of FloodCrest(ft)Streamflow(cfs)CategoryCode
1889-06-0140220000MajorC1 C8
1924-03-3032.4130000MinorC1 C4 C9
1924-05-1335160000MajorC1 C8
1929-04-1730.3110000MinorC1 C8

Codes and description

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|Crest 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; Good Data

Updated: 08:00 PM May 28, 2014