PRINCE WILLIAM SOUND, COPPER AND BERING RIVER SALMON STATISTICS 239 
stream through the summer months and is noticeably cloudy in the other seasons. 
Not all of its tributaries are discolored, however, as several clear streams form the 
headwaters of the rivers draining the Copper River basin. The entire river system 
abounds in lakes, many of which are more or less turbid, due to the action of galciers, 
yet in all this elaborate network of streams and lakes, favorable spawning grounds 
are comparatively limited and aggregate much less than in many smaller streams in 
other parts of the territory. 
Through much of its length, the Copper is a swiftly flowing river heavily loaded 
with silt which is deposited at its mouth. In the course of years, a large delta has 
thus been formed, spreading completely between the east and west boundaries of the 
district, while large quantities of silt have been swept into the eastern part of Prince 
William Sound through Orca Inlet. Conspicuous sand bars have also been formed 
across this stretch of coast about 4 miles out from the edge of the delta, giving further 
proof of the tremendous quantity of solid material being constantly brought down by 
the river. Through the delta thus formed, the river has maintained several channels 
in addition to the main outlet just west of Cottonwood Point. These channels, or 
sloughs as they are commonly called, and the mud flats between the sand bars and 
the delta, have been the principal fishing grounds in the Copper River district ever 
since exploitation of its runs of salmon began. 
