Notes On The Geology Of Southwestern Idaho And Southeastern Oregon
By Israel C. Russel
Bulletin No. 217, Series B, Descriptive Geology, 32Department of The Interior United States Geological Survey Charles D. Walcott, Director
INTRODUCTION
During the summer of 1902 I made a rapid reconnaissance through portions of southwestern Idaho and southeastern Oregon for the purpose, principally, of ascertaining in what localities, if any, the geological conditions are favorable to obtaining flowing water by drilling wells. This search was more successful than had been hoped, and a preliminary report on the artesian basins discovered has already been published (See Note).The explorations referred to were in continuation of similar work done the preceding summer in southern Idaho, a report on which was published as Bulletin No. 199 of the United States Geological Survey. The aim of the present paper is to put on record such observations relating to the general geology of the region traversed as it is thought may be of interest, more particularly to the people of Idaho and Oregon, and also in certain instances serve to supplement the report referred to on artesian conditions. During the reconnaissance I was assisted by Mr. Scott Turner and Mr. Robert H. Dawson, students of the University of Michigan. Our journey began at Boise, Idaho, on July 6, and ended at the same place on September 6, 1902. The route followed was planned so as to traverse as many as possible of the valleys of southwestern Idaho and southeastern Oregon, in which rich agricultural land is plentiful and where artesian conditions are most likely to be present. Portions of Canyon and Owyhee counties, Idaho, and of Malheur and Harney counties, Oreg., were examined; but it is not to be understood that anything like a geological survey of the immense territory included in these counties was undertaken. This paper is simply an account of observations made during a rapid reconnaissance, principally in the way of supplementing the study of artesian conditions, and should not bo judged in any other light.
Note – Water Supply and Irrigation, Paper No. 78, U.S. Geological Survey, 1903. (Page 7)
CLIMATE AND VEGETATION
The leading characteristics of the climate of the portions of. Idaho and Oregon here considered are: Small precipitation; generally cloud-less skies; hot, dry summers; and moderately cold winters, during which there is some rain and snow, but not enough to make the mean annual precipitation large. Something of the nature of the prevailing climatic conditions may be judged from the following data, compiled from the report of the United States Weather Bureau for 1900, which pertain to localities within or near the region here discussed. All the localities mentioned in the above table are situated in valleys. On the mountains cooler and more humid atmospheric conditions prevail. The snowfall is light in the valleys and, like the mean annual precipitation, increases with elevation, but not in a direct and simple ratio. The general climatic conditions of both Idaho and Oregon vary in a conspicuous manner at different localities. In Idaho the northern and more mountainous portion of the State is much colder and more humid than the intensely arid southern portion. In Oregon aridity is the prevailing condition in the southeastern and central parts of the State, with increasing humidity toward the west and northeast. The portion of each State here described, while characteristic of its most arid valleys and most desolate mountains, must not be considered as representative of the entire political division of which it forms a part. (Page 8)
Weather Records for Payette, Idaho for the Year 1900
Locality – Payette, Idaho
Precipitation – 10.60 Inches
Minimum Temperature – 10 Degrees
Maximum Temperature – 104 Degrees
Mean Temperature – 53.7 Degrees
Killing Frost, Last in Spring – April 13
Killing Frost, First in Autumn – September 25
Snow – 19.8 Inches
