LOCATION.--Lat 38°57'36.6", long 77°02'31.4", Washington, DC, Hydrologic Unit 02070010,
   on right bank at downstream side of bridge on Joyce Rd. 
DRAINAGE AREA.--63.7 mi2.
PERIOD OF RECORD.--April 2007 to September 2012 (gage heights and discharge measurements only).
   October 2012 to current year.
GAGE.--Water-data recorder and crest-stage gage. Datum of gage is 136.78 ft above North American 
   Vertical Datum of 1988.
REMARKS.--Flow affected by two upstream reservoirs which control flow from about 25 mi2,
   Needwood Lake on Rock Creek since Sept. 1966 and Bernard Frank Lake on North Branch Rock Creek 
   since February 1968. U.S. Geological Survey water-data telemeter at station.
EXTREMES FOR PERIOD OF RECORD.--Maximum discharge, 4,440 ft³/s, Apr. 30, 2014, gage height, 9.68 ft;
   minimum discharge, 4.58 ft³/s, Sept. 21, 2015.  
COOPERATION.--Funding for the operation of this station is provided by the Montgomery County 
   Department of Environmental Protection, and the U.S. Geological Survey.