Water Quality as a Function of Discharge from the Roanoke Rapids Reservoir duringHydropower Generation

摘要

The effect of springtime water releases from Roanoke River reservoirs ondownstream water quality was examined by whole water grab samples collected at two locations. At Pollock's Ferry (River Mile 105) near Scotland Neck, North Carolina, surface water samples were collected one day each week from 14 April to 8 June 1988. Within the Roanoke River delta, water samples were collected at four stations once each week for nine weeks starting 14 April and ending 10 June. Water releases from Roanoke Rapids Reservoir caused instream flows to fluctuate from 1,100 to 18,000 cubic feet per second (cfs) in January and February. During the major portion of striped bass (Morone saxatilis) spawning activity (from mid-April through late May), the hydroelectric peaking activity moderated and flows ranged from 5,900 to 8,300 cfs. In early June, normal hydropower operations resulted in river flows fluctuating between about 2,000 and 15,000 cfs. Rainfall events during the study period influenced water release schedules and influenced water quality downstream. We conclude that water quality at Pollock's Ferry, 22 miles below Roanoke Rapids Dam, was largely influenced by water releases from Roanoke Rapids reservoir.