South Branch Potomac River near Petersburg, Grant County WV (PETW2)
Gage Location: Grant County, West VirginiaSite Location: Grant County, West Virginia
Latitude: 38.991Longitude: -79.176Elevation: 968.34 ft. MSLDrainage Area: 651 Sq. Mi.
Minor Stage: 14 ft. Moderate Stage: 15 ft.Major Stage: 17 ft.
First Flood: 1877-11-24Last Flood: 2014-05-16 Crest: 14.38 ft.Datum change: 2011-03-16Number of Floods: 30

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Date of FloodCrest(ft)Streamflow(cfs)CategoryCode
1877-11-2421.259000MajorC1 C8 F1 G1
1924-05-1319.245000MajorC1 C8 F1 G1
1932-02-0415.1828300ModerateC1 G1
1936-03-1720.349800MajorC1 G1
1939-02-0314.626000MinorC1 G1
1940-05-3114.525600MinorC1 G1
1942-05-1613.9323400MinorC1 G1
1942-05-2213.6922600MinorC1 G1
1949-06-1722.8362000MajorC1 G1
1954-10-1513.3421600MinorC1 G1
1963-03-1914.7926700MinorC1 G1
1967-03-0714.7426600MinorC1 G1
1972-10-0616.1632100ModerateC1 G1
1973-12-2713.1321000MinorC1 G1
1974-06-0213.5822500MinorC1 G1
1975-10-1813.4722200MinorC1 G1
1976-10-0915.1428100ModerateC1 G1
1978-01-2613.9323600MinorC1 G1
1982-03-2013.4521900MinorC1 G1
1984-02-1413.120700MinorC1 G1
1985-11-0521.8130000MajorC1 G1 G3
1996-01-192082000MajorC1 G3
1996-05-1714.2928800MinorC1 G3
1996-09-0622.2113000MajorC1 G3

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