West Branch Susquehanna River at Williamsport, Lycoming County PA (WILP1)
Gage Location: Lycoming County, Pennsylvania	Site Location: Lycoming County, Pennsylvania
Latitude: 41.236	Longitude: -76.907	Elevation: 494.98 ft. MSL	Drainage Area: 5682 Sq. Mi.
Minor Stage: 20 ft.	Moderate Stage: 21 ft.	Major Stage: 30 ft.
First Flood: 1865-03-17	Last Flood: 2011-04-28 Crest: 20.27 ft.	Datum change: 1928-10-01	Number of Floods: 39

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Date of Flood Crest(ft) Streamflow(cfs) Category Code 1865-03-17 27.5 -9999 Moderate *** NWS 1889-06-01 32.4 252000 Major *** 1894-05-21 31 -9999 Major *** NWS 1898-03-24 21 141000 Moderate *** 1901-12-15 20.7 138000 Minor *** 1902-03-01 21.7 149000 Moderate *** 1904-03-04 21 141000 Moderate *** 1909-05-01 21 141000 Moderate *** 1913-03-27 20.4 135000 Minor *** 1916-03-29 20.5 136000 Minor *** 1916-06-17 21 141000 Moderate *** 1918-02-21 21.4 145000 Moderate *** 1919-05-22 20.9 140000 Minor *** 1920-03-13 20.4 135000 Minor *** 1923-03-05 21.6 147000 Moderate *** 1936-03-12 23.6 164000 Moderate none 1936-03-18 33.57 264000 Major none 1940-04-01 22.73 146000 Moderate none 1942-12-31 23.03 148000 Moderate none 1946-05-28 29.63 223000 Moderate none 1948-04-15 20.63 124000 Minor none 1950-11-26 28.11 206000 Moderate none 1951-03-31 20.15 119000 Minor none 1956-03-09 20.37 121000 Minor none 1959-01-22 22.99 150000 Moderate none 1960-04-01 20.92 127000 Minor none 1961-02-26 21.68 136000 Moderate none 1964-03-11 27.25 197000 Moderate (6) 1972-06-23 34.75 279000 Major (6) 1975-09-26 24.7 169000 Moderate (6) 1979-03-06 22.73 147000 Moderate (6) 1984-02-15 25.59 178000 Moderate (6) 1993-04-01 20.52 122000 Minor (6) 1996-01-20 26.71 191000 Moderate (6) 2004-09-18 27.79 203000 Moderate (6) 2010-01-26 20.12 118000 Minor none 2010-03-14 24.9 -9999 Minor none 2010-12-02 23.25 152000 Moderate none 2011-04-28 20.27 120000 Minor none

MARFC Codes
Code Description
(!!!) Datum changed during this year.
(1) Backwater Effect.
(2) 15.77 ft also occurred on 11/25/1950 but only counted as one flood.
(3) Estimated from currrent USGS rating table.
(4) Estimated height from the USGS.
(5) Gage height at a different site and/or datum
(6) Discharge affected by Regulation or Diversion
(7) Due to changes, prior floods were based on present flood stage. Therefore, flood data could possibly be incomplete.
(8) Gage is a staff gage and not the offical USGS gage. Therefore, some floods may be missing from our study.
(9) Discharge effected by snow-melt, ice jam or debris jam break up
(A) Discharge affected to unknown degree by regulation or diversion.
(B) Month or day of occurrence is unknown or not exact.
(C) All or part of the record affected by urbanization, mining, agricultural changes, channelization, or other factors.
(D) Crest height adjusted to current datum.
(E) Estimated discharge.
(F) Only annual maximum peak available for this year.
(O) This flood occurred at a previous flood stage that is lower than the current flood stage. This is only a historical flood.
** Crest information looks reasonable despite potential problems. This data was used in our study.
*** Crest information looks unreliable and incomplete and was not used in our flood frequency study.
**** Gauge was discontinued in 2004. 2004 and later was not used in our study.
none No code

Updated: 08:58 AM Jun 28, 2012