PROGRESS IN BIOLOGICAL INQUIRIES, 19 30 



601 



other hand the river bed in the vicinity of the screen consisted of 

 o^ravel bars overrun by shaUow water, which was attractive to the 

 nsh. A large number were seen to make their nests and spawn here. 

 At times as numy as 15 to 20 sahnon woukl be found in the timber 

 pool located at the end of the electric screen. This evidence of the 

 action of the screen in leading- even a small number of fish to the pool 

 is considered quite encouraging as physical conditions at its entrance 

 were not entirely favorable. 



FISH LADDERS 



The activities of 1930 in the fish-ladder field include: (1) The 

 building of new, modern concrete fish ladders at two Government 

 projects, these being the Wapato Dam on the Yakima River and 

 the Sprague River Dam in Oregon; (2) specification and supervision 

 of construction on alteration of fish ladder at Gold Ray power plant 

 on the Rogue River; (3) inspection and supervision of progress of 



Figure 7. — Wapato flsh ladder. View looking toward west sliorc simwiiiL; side en- 

 trance pool and shear boom raft at top of dam 



construction of the fish ladders si^ecified for the Rock Island de- 

 velopment; and (4) specification of required fish-protective devices 

 for certain power applications submitted to the Federal Power 

 Commission. 



Wapafo fish ladder. — The success of the Sunnyside fish ladder built 

 by the U. S. Bureau of Fisheries last year was immediate, and this 

 Installation emphasized the need of a similar structure at the AVapato 

 Dam, of the U. S. Indian Irrigation Service, located about 31/2 miles 

 up tlie Yakima River from the Sunnyside Dam. Accordingly, the 

 aid of the Department of the Interior was solicited and funds 

 secured from it for the construction of the ladder. Design of the 

 Wapato ladder followed closely the features of the Sunnyside in- 

 stallation. The U. S. Reclamation Service showed a fine spirit of 

 cooperation in making available to us the services of their construc- 

 tion organization. The ladder has been installed in the east channel 

 of the river at the Wapato diversion. Crest length of the dam is 



