and Deubler, in part (1968), compiled 

 the seasonal isohalines of the sound 

 and coastal waters of North Carolina. 

 The rivers that empty into the coast- 

 al sounds (Figure 1) are most af- 

 fected in early spring, especially 

 March or April, when runoff (the re- 

 sult of rains or melting snow up- 

 stream) is highest. The major water- 

 sheds of North Carolina, from north 

 to south, are the Chowan-Roanoke, 

 Albemarle Sound, Pamlico-Pungo River, 

 Neuse River, Bay River, Newport Riv- 

 er, White Oak River, New River, and 

 Cape Fear River (Figure 1). These 

 likewise feed into the major sounds 

 of Albemarle-Currituck, Croatan, 

 Roanoke, and Pamlico. Numerous 

 smaller sounds exist south of Pamlico 

 Sound but they are usually short in 

 length or subject to more oceanic in- 

 fluences than freshwater runoff 

 (Figure 1). Most of the major rivers 

 of North Carolina have extensive wa- 

 tersheds and are usually 10m or less 

 deep. The Cape Fear River, in the 

 southern portion of the state, is 

 the largest and is dredge-maintained 

 upstream at 13 to 15m to Wilmington, 

 North Carolina. 



Albemarle and Currituck Sounds 

 are typically freshwater habitats 

 during most of the year. Spring 

 freshet runoff of these freshwaters 

 extend 28 km into the low saline 

 8 ppt to 20 ppt Croatan and Roanoke 

 Sounds thereby carrying fresh waters 

 southward to Oregon Inlet (Figure 1). 

 During the late fall (November) sa- 

 line waters from Croatan and Roanoke 

 sounds may extend into and along the 

 lower eastern third of Albemarle 

 Sound . 



The Pamlico-Pungo rivers are 

 usually saline from near Washington 

 and Winsteadville , North Carolina. 

 Spring or sudden runoffs lower these 

 10 ppt to 17 ppt waters to ppt for 

 distances of 60 and 15 km respective- 

 ly. 



The short 5 km Bay River is not 

 included in the discussions of this 

 study as it usually does not have a 

 clearly defined freshwater intrusion 

 zone. Instead runoff waters flow out 

 into Pamlico Sound as a layer over 

 the highly saline bottom waters. 



The Neuse River is fresh-water 

 to just downstream of Grifton, North 

 Carolina. The affected area of 

 spring freshwater intrusion moves 

 ppt salinity waters 35 km to the 

 junction of the Neuse River with Pam- 

 lico Sound. Surface waters of Pam- 

 lico Sound, during hurricane or 

 other heavy rains, have been found 

 fresh the entire extent from west to 

 east and often pour out the inlets 

 in the outer banks as a definite 

 visible water mass (Schwartz 1973). 

 However, 7 ppt to 32 ppt salinities 

 usually prevail within Palmico Sound 

 (Schwartz and Chestnut 1973) . 



The Newport River is a short 

 compressed estuary of 12 km and is 

 subject to large saline intrusions 

 from the nearby Atlantic Ocean (Hyle 

 1976). The freshwater runoff zone has 

 extended downstream for 4 to 5 km 

 from its confluence with the estuary 

 near the "Crossrocks . " 



The White Oak River is a long 

 shallow river subject to high saline 

 intrusions from the nearby ocean in 

 its lower courses. During runoff 

 the vertical freshwater face has been 

 moved downstream 15 km to Stella, 

 North Carolina. 



The New River is another saline 

 intrusion-influenced river, yet the 

 runoff zone is often extended south- 

 east of Jacksonville, North Carolina 

 for 12 km. 



The Cape Fear River is a swift 

 river which, in its lower 30 km, is 

 subject to 2-m tidal influences. 

 Cape Fear experiences the highest 



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