EFFECTS OF CHANNEL MORPHOLOGY ON EVAPORATIVE HEAT LOSS FROM ARID-LAND STREAMS

摘要

Stream evaporation was studied along the Middle Fork of the John Day River in northeastern Oregon during the summer of 1998. Over a 3-4 day period, evaporation rates and meteorological data were acquired at a given site; a total of nine sites were sequentially instrumented in this manner. Stream channel characteristics were analyzed to evaluate potential effects on stream evaporation rates. The alignment of the stream channel with respect to wind direction, the degree of stream channel incision, and the steepness of streambanks on the windward side of the channel were found to influence the movement of wind at the stream surface, thereby affecting evaporative heat loss.