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Phosphorus loads for September 15 to October 20 ranged from 30 tons in the Lumber River (site 45) to 370 tons in the Neuse River near Fort Barnwell (site 32; fig. 19). The esti- mated phosphorus load at Kinston (site 28) was 66 percent of the mean annual phosphorus load of 350 tons (Hamed and others, 1995). The esti- mated load during flooding at Tar- boro (site 14) was 89 percent of the mean annual load of 270 tons (Harned and others, 1995). Phos- phorus yields ranged from 0,03 to 0.2 I tons/mi2 (fig. 18B). The lowest yield was in the Lumber River Basin 400 3S0 total phosphorus load (fig. 19), the North- east Cape Fear had a greater yield (fig. 18B), In the Neuse and Cape Fear River Basins, total phos- phorus yields result- ing from Hurricane Floyd were generally slightly less than those resulting from Hurricane Fran. In the Tar River Basin, however, the phosphorus yield ,.-1.__._ ~ h~...,...'w , " w ,'. =:l Streamflow measurement using acoustic Doppler current profiler and radio transmitter, Potecasi Creek resulting from Hurricane Floyd was nearly triple that from Hurricane Fran. The concentration of phospho- rus was similar, but the quantity of streamflow that resulted from Hurri- cane Floyd was much greater. As previously discussed, resi- dence time in the Pamlico River and Neuse River estuaries was greatly reduced during the flooding. Conse- quently, nutrients and organic matter that are typically biochemically transformed or settle in these systems likely passed directly through the estuaries to Pamlico Sound. The effects of this massive pulse of nitro- gen, phosphorus, and organic carbon on the Pamlico Sound ecosystem remains to be seen. (site 45), and the highest yield was in the Northeast Cape Fear River (site 43). The yield was 0.19 tons/mi2 for the Tar-Pamlico River Basin above Washington (site 18; this estimate was for September based on the monthly average discharge and the median concentra- tion). Although the Neuse River near Fort Barnwell (site 32) carried a greater w Z 0 ~ 300 ;; ci "' 0 250 ~ w Cape Fear River :> ~ at lock 1 0 200 I ~ ~ w 0 Northeast Cape Fear River ~ ~ 150 w near Chinquapin > I ~ :> 100 " :> Lumber River at u Boardman 50 I 9119 9123 9127 10/1 10/5 10/9 10/13 10/17 1999 Figure 19, Cumulative total phosphorus load at sites near the mouths of the Tar, Neuse, Cape Fear, Northeast Cape Fear, and Lumber Rivers. ~ w C u z US Highway 17 in Brunswick County Salinity and Dissolved Oxygen in the Pamlico and Neuse River Estuaries Floodwaters entering the Pamlico and Neuse River estuaries flushed brackish water out of the estuaries. High flows associated with Hurricane Dennis resulted in increased stratification and decreased salinity in the Two Months of Flooding in Eastern North Carolina, Scptember-Oclober 1999