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 during this period may be incomplete and therefore was not used in frequency calculations. Some of the floods are based on current flood stage and nearby gage information.
C2|Crest information during this period 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: 07:31 AM Dec 19, 2014