LOCATION.--Lat 39°18'37.1", long 76°47'32.7", Baltimore County, MD, Hydrologic Unit 02060003, on left bank at upstream side of highway bridge at Hollofield, 0.3 mi downstream from Dogwood Run, 3.0 mi north of Ellicott City, and 28 mi upstream from mouth.
DRAINAGE AREA.--285 mi².
PERIOD OF RECORD.--May 1944 to January 1992, March 1994 to September 1995, January 2000 to September 2004, April 2010 to current year.
REVISIONS HISTORY.--https://waterdata.usgs.gov/nwis/peak?site_no=01589000: 2013 (P).
REVISIONS HISTORY (WATER QUALITY).--https://waterdata.usgs.gov/nwis/dv/?site_no=01589000: 2014.
GAGE.--Water stage recorder and crest-stage gage. Datum of gage is 186.99 ft above North American Vertical Datum of 1988, from digital elevation model. Prior to May 1, 2010, at site on downstream side of bridge at same gage datum. Prior to June 22, 1972, water-stage recorder at site on opposite bank at same gage datum.
REMARKS.--Flow regulated by Liberty Reservoir, 11 mi upstream, beginning July 22, 1954, usable capacity, 42,070,000,000 gal; dead storage, 1,260,000,000 gal. Diversions upstream from station for municipal supply of Westminster (sewage effluent discharged into Little Pipe Creek), and from Liberty Reservoir beginning Feb. 26, 1953, for municipal supply of Baltimore, and beginning February 1970 for a small municipal supply for part of Carroll County. U.S. Geological Survey satellite data-collection platform at station.
EXTREMES FOR PERIOD OF RECORD.--Maximum discharge, 80,600 ft³/s, June 22, 1972, gage height, 31.30 ft; minimum discharge, 5.7 ft³/s, Aug. 22, 23, 2002.
COOPERATION.--Funding for the operation of this station is provided by the Baltimore County Department of Environmental Protection & Sustainability.