DRAINAGE AREA.--11,560 mi2.
PERIOD OF RECORD.--March 1930 to current year.
REVISIONS HISTORY.--WSP 726: Drainage area. WDR MD-DE-75-1: 1973-74(M).
GAGE.--Water-stage recorder, crest-stage gage, and concrete control. Datum of gage is 37.20 ft above
North American Vertical Datum of 1988. Prior to June 7, 1930, nonrecording gage, and June 7, 1930
to Jan. 22, 1965, water-stage recorder at site 1 mi upstream on right bank at same gage datum.
REMARKS.--Diversions since June 1959. U.S. Geological Survey satellite data-collection platform at
EXTREMES FOR PERIOD OF RECORD.--Maximum discharge, 484,000 ft3/s, Mar. 19, 1936,
gage height, 28.1 ft, at site then in use; minimum discharge, 66 ft3/s, Sept. 9, 1966.
Minimum daily discharge observed at gaging station, 121 ft3/s, Sept. 9, 1966, does not include
diversion of 489 ft3/s for municipal use; minimum daily discharge (adjusted), 601 ft3/s,
Sept. 10, 1966, includes diversion of 449 ft3/s for municipal use.
EXTREMES OUTSIDE PERIOD OF RECORD.--Flood of June 2, 1889, was of approximately the same magnitude
as that of March 19, 1936.
COOPERATION.--Funding for the operation of this station is provided by the U.S. Geological Survey.
Access to gage site provided by the Baltimore District, U.S. Army Corps of Engineers. Water
temperature and specific conductance monitoring are supported by the U.S. Army Corps of Engineers.