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USGS Water-Year Summary 2024
02077500 HYCO RIVER NEAR DENNISTON, VA
LOCATION - Lat 36°35'16", long 78°53'56" referenced to North American Datum of 1927, Halifax County, VA, Hydrologic Unit 03010104, on left bank 60 ft upstream from bridge on U.S. Highway 501, 0.8 mi upstream from Mayo Creek, 2.5 mi northeast of Denniston, and 7.3 mi south of South Boston.
DRAINAGE AREA - 288 mi².
REVISIONS HISTORY - WSP 1503: 1930(M). WSP 1723: 1930(m). WDR VA-75-1: 1974. OFR 2006-1308: Drainage area.
SURFACE-WATER RECORDS
PERIOD OF RECORD - July 1929 to March 1934, October 1950 to March 2014 (discontinued). Monthly discharge only for some periods, published in WSP 1303.
GAGE - Water-stage recorder. Datum of gage is 315.24 ft NGVD of 1929. July 10, 1929, to Mar. 14, 1934, nonrecording gage, at present site and datum.
REMARKS - Records good except for estimated daily discharges, which are fair, and other periods as noted. Records fair above 1,400 ft³/s. Small diurnal fluctuation at low flow in some years caused by mill upstream from station. Since September 1964, flow regulated by Hyco Lake 15.7 mi upstream, capacity 75,480 acre-ft, and since Apr. 26, 1974, by Roxboro Steam-Electric Generating Plant Afterbay Reservoir, capacity 12,000 acre-ft. Statistics of monthly mean data and summary statistics for water years 1929 - 1934, 1951 - 1964 (unregulated flow) are available in previous data books, water years 1991 - 1998. Maximum discharge, 10,800 ft³/s, from rating curve extended above 8,200 ft³/s. Water-quality records for some prior periods have been collected at this location.
EXTREMES OUTSIDE PERIOD OF RECORD - Floods in August 1928 and September 1945 reached stages of 26.4 ft and 25.6 ft, respectively, from floodmarks.
EXTREMES FOR PERIOD PRIOR TO REGULATION - 1929-34, 1951-64: Maximum peak flow 7,630 ft³/s, Oct. 3, 1929, gage height 21.88 ft. Instantaneous low flow 0.004 ft³/s, Sept. 14, 1932
