490 U. S. BUREAU OF FISHEEIES 



of approximately 200 feet upstream to the head of the Upper Falls. 

 The rise in water surface along this 200 feet of channel is normally 

 about 12.8 feet. 



The most practical solution of the difficulty is held to be by use of 

 timber dams constructed of heavy logs faced with planking. The 

 installation of three such new log dams along the critical stretch of 

 channel was recommended. 



NEW AND PROPOSED POWER PROJECTS 



A matter of fundamental importance to fish conservation is the 

 provision of proper equipment for the safe handling of fish at hydro- 

 electric power developments. A good share of the, activities of this 

 investigation has been devoted to this work at new and proposed 

 projects in the Northwest. During 1931 the following major devel- 

 opments claimed attention: 



(1) Kock Island development of Puget Sound Power & Light Co. 

 on the Columbia Eiver, Wash. 



(2) North River project of Western Washington Electric Light 

 & Power Co. on North River, Wash. 



(3) Ariel development of Inland Power & Light Co. on Lewis 

 River, Wash. 



(4) Cascade Rapids projects (application of Columbia River 

 Power Co. and application of Charles O. Lentz et al.) at Cascade 

 Rapids on Columbia River. 



The Bock Island project. — The original requirements for fish pro- 

 tection as written into the project license of this major power de- 

 velopment of the Puget Sound Power & Light Co. on the Columbia 

 River near Wenatchee, Wash., called for the protection of both the 

 intake and tailrace waters by means of electric fish screens. How- 

 ever, with the completion of the power house and east-channel spill- 

 wa}'^ dam, in the winter of 1930, opportunity was afforded for the 

 study of physical conditions at the site, and it became evident that 

 there was good possibility that migrating fish might safely negotiate 

 the waters about the power house without the aid of electric screens. 

 Conferences were held with the engineers of the Stone & Webster 

 Co. in Boston, and after thorough study it appeared that in fairness 

 to the company immediate installation of the electric screens should 

 not be required, but that a trial period of operation should be allowed 

 to determine whether or not such equipment would be necessary. 



Under date of September 4, 1931, the company obtained an amend- 

 ment to their Federal Power Commission license providing for 

 change in the plan of development. As regards safety, location and 

 design and relocation of the dam have made possible the construction 

 of a fish ladder offering many advantages over the structure origi- 

 nally proposed for the west channel. 



The lower portion of the new ladder consists of a series of pools- 

 excavated in solid rock and the upper portion is of reinforced con- 

 crete exactly similar to the fish ladder at the power house, the grade 

 being 1 to iO and the pools being 10 feet long by 20 feet wide and 

 providing for minimum depth of 4 feet of water. Under the new 

 plan of development ultimate pond elevation has been set 4 feet 

 lower than the height originally proposed. 



