INTRODUCTION 



Th© purpose of the Colxambia River Stream Survey is to provide data 

 for the evaluation of eaoh stream, or portion of stream, from the stand- 

 point of its present and potential value in relation to the maintenance 

 of the salmon resources of the Columbia River. The Columbia River water- 

 shed has been divided into several survey areas or units as shown in 

 Pigvire 1« This report deals with the streams in Area VI. 



Area VI includes the tributaries to the Snake River from a point 

 just above the mouth of the Grande Ronde River through the Payette 

 River. The area begins approximately 170 miles above the mouth of the 

 Snake River emd extends for a distance of 197 miles upstresuoa. For more 

 than 125 miles of this distance, up to Homestead, Oregon, the Snake 

 River extends through an immense canyon. One section of the Snake River 

 Canyon, known as Hell's Canyon, is the deepest gorge on the North Ameri- 

 can continent, and extends from a point about 217 miles above the mouth 

 for a distance of 30 miles upstream. 



Although it is impossible to conduct a biological survey of the 

 Snake River through Hell's Canyon, it may be stated that this section 

 is of no value to salmon because of the steep gradient and the bedrock 

 composition of the river bed* 



Above the mouth of Pine Creek the river has fewer canyons, and in 

 the upper part of the area portions of the main stream might be utiliz- 

 ed to some extent by spawning chinook salmon. However, the chief value 

 of the Snake River to salmon has been as a passageway to some of its 

 large tributary systems. In Area VI these have been divided for con- 

 venience into four sub-areas. On the Idaho side of the Snake River 

 these are (1) the Salmon River System, (2) the Weiser River System, and 

 (3) the Payette River System. On. the Oregon side of the Snake River 

 the sub-area (4) includes the Imnaha River, Pine Creek, Powder River, 

 euad Burnt River. A great many small streajns enter the Snake River 

 Cajiyon, but all of them have steep gradients, and are of no value to 

 salmon. 



Various individuals had a part in the field work and, so far as 

 possible, the names of those who made the observations upon which the 

 following account is based and the dates on which the surveys were 

 made are given in connection with the treatment of eaoh stream. For 

 convenience there is given here a complete list of all the men who were 

 engaged in the survey of Area VTi - F. G. Bryant, D. G. Frey, M. G. Hana- 

 van, W. M. Morton, Z. E. Parkhurst, J. L. Wilding, and P. D. Zimmer, 



