Stream Temperature Climate in a Set of Southern Appalachian Streams
Water temperature patterns are described for five streams on forested watersheds in western North Carolina as part of stream monitoring in the Wine Spring Ecosystem Management Area. Elevation ranged from 918 m at Nantahaia Lake to 1660 m at Wine Spring Bald with, four temperature measurement sites Itied between 1145 m and 1200 m elevation, and one site at 925 m. Summer daily maximums were relatively constant, 13 to 16°C; whereas, winter minimums ranged from 1 to 8°C. These streams are subjected to a daily temperature range of 0 to 1°C in the summer, 1 to 2°C in the fall, 1 to 3°C in winter, and 1 to 5°C in the spring. Summer precipitation events did not always appear to affect stream temperatures but winter storms may have raised daily minimum temperatures. Water temperature responded to major fluctuations inair temperature and solar radiation more consistently than to precipitation input. In winter, stream temperatures increased an average of 0.3°C with decreasing elevation from 1200 m to 1145 m. In late summer and fall, stream temperatures increased by 1.2°C as elevation decreased from 1145 m to 925 m. However, in winter, the larger stream at 925 m was as cold as the smaller stream at 1200 m. From November through April, water temperatures in one branch of the stream system, draining a south facing slope with shallow soils, were 0.6 to 1.5°C warmer than those in an adjacent stream at the same elevation.