PROVISIONAL DATA SUBJECT TO REVISION

LOCATION.--Lat 39°18'37.1", long 76°47'32.7", Baltimore County, 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.
GAGE.--Water stage recorder and crest-stage gage. Datum of gage is 186.9 ft above North American Vertical Datum of 1988, 
   from digital elevation model. Prior to June 22, 1972, water-stage recorder at site on opposite bank at same datum.   
   Prior to May 1, 2010, at site on downstream side of bridge at same 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.  Turbidity values that were determined to be a result of debris on the sensor; 
   a function of incident sun angle; or other phenomena that did not appear to be correlated to suspended-sediment 
   concentration were removed by the hydrogopher. 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 Maryland Geological Survey,
   and the U.S. Geological Survey.