USGS Water-Year Summary 2020
02047500 BLACKWATER RIVER NEAR DENDRON, VA
LOCATION - Lat 37°01'30", long 76°52'30" referenced to North American Datum of 1927, Surry County, VA, Hydrologic Unit 03010202, on left bank 10 ft upstream from Walls Bridge on State Highway 617, 1.2 mi downstream from Cypress Swamp, and 3.5 mi southeast of Dendron.
DRAINAGE AREA - 290 mi².
- OFR 2006-1308: Drainage area.
PERIOD OF RECORD - October 1941 to December 1986, July 1988 to current year.
GAGE - Water-stage recorder. Datum of gage is 0.00 ft NAVD of 1988. October 1941 to Aug. 13, 1980, at site 25 ft upstream and at datum of 30.99 ft NGVD of 1929 (U.S. Army Corps of Engineers bench mark). Aug. 13, 1980 to Nov. 28, 2012, at current site and at datum of 30.99 ft NGVD of 1929.
COOPERATION - Records were provided by the Virginia Department of Environmental Quality - Water Division.
EXTREMES OUTSIDE PERIOD OF RECORD - Flood in August 1940 reached a stage of 13.1 ft, from U.S. Army Corps of Engineers floodmarks, discharge, 10,000 ft³/s, from rating curve extended above 4,900 ft³/s.
PERIOD OF RECORD - October 2006 to September 2008.
PERIOD OF DAILY RECORD - March 2007 to September 2008.
COOPERATION - Daily records were provided by the Virginia Department of Environmental Quality - Water Division.
INSTRUMENTATION - Specific conductance and water temperature monitor. Electronic data logger with 15-minute recording interval.
EXTREMES FOR PERIOD OF DAILY RECORD -
SPECIFIC CONDUCTANCE: Maximum, 368 microsiemens/cm, Aug. 6, 2008; minimum, 44 microsiemens/cm, Apr. 23, 2008.
WATER TEMPERATURE: Maximum, 29.4°C, Aug. 9, 2007; minimum, 0.0°C, Jan. 4, 5, 21, 22, 26, 2008.