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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Height Above Flood Stage for Entire Period of Record
Height Above FSTotal OccurencePercent of Crest OccurrenceCumulative Total Flood OccurrencePercent of Floods above Listed Value
30 ft to 31 ft215.430 ft or above 13100.0
31 ft to 32 ft17.731 ft or above 1184.6
32 ft to 33 ft215.432 ft or above 1076.9
33 ft to 34 ft00.033 ft or above 861.5
34 ft to 35 ft00.034 ft or above 861.5
35 ft to 36 ft323.135 ft or above 861.5
36 ft to 37 ft215.436 ft or above 538.5
37 ft to 38 ft00.037 ft or above 323.1
38 ft to 39 ft00.038 ft or above 323.1
39 ft to 40 ft00.039 ft or above 323.1
40 ft to 41 ft17.740 ft or above 323.1
41 ft to 42 ft17.741 ft or above 215.4
42 ft to 43 ft00.042 ft or above 17.7
43 ft to 44 ft00.043 ft or above 17.7
44 ft to 45 ft00.044 ft or above 17.7
45 ft to 46 ft00.045 ft or above 17.7
46 ft to 47 ft00.046 ft or above 17.7
47 ft to 48 ft17.747 ft or above 17.7
Height Above Flood Stage After Datum Change
Height Above FSTotal OccurencePercent of Crest OccurrenceCumulative Total Flood OccurrencePercent of Floods above Listed Value
30 ft to 31 ft112.530 ft or above 8100.0
31 ft to 32 ft112.531 ft or above 787.5
32 ft to 33 ft112.532 ft or above 675.0
33 ft to 34 ft00.033 ft or above 562.5
34 ft to 35 ft00.034 ft or above 562.5
35 ft to 36 ft225.035 ft or above 562.5
36 ft to 37 ft225.036 ft or above 337.5
37 ft to 38 ft00.037 ft or above 112.5
38 ft to 39 ft00.038 ft or above 112.5
39 ft to 40 ft00.039 ft or above 112.5
40 ft to 41 ft00.040 ft or above 112.5
41 ft to 42 ft112.541 ft or above 112.5
42 ft to 43 ft00.042 ft or above 00.0
43 ft to 44 ft00.043 ft or above 00.0
44 ft to 45 ft00.044 ft or above 00.0
45 ft to 46 ft00.045 ft or above 00.0
46 ft to 47 ft00.046 ft or above 00.0
47 ft to 48 ft00.047 ft or above 00.0





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: 08:09 AM Feb 08, 2013