PEOGRESS IF BIOLOGICAL INQUIRIES^ 19 31 487 



race screen was not desired. The bureau representatives held that 

 the operation of the electric screen was in no way responsible for 

 the electrocution of the salmon, and pointed to the record of success 

 which this screen had enjoyed for a period of more than two years. 



During the conference Avith this committee and the power company 

 it developed that upon April IG and May 29 there had been short 

 circuits on a 66,000-volt line at Gold Ray. The Gold Ray plant is 

 grounded into the river and the path of the current for these short 

 circuits was through the river to Grants Pass substation No. 2. This 

 explained the electrocution of the salmon in the vicinity of Gold Ray 

 plant and for a considerable distance down river, for at this time this 

 stretch of the channel was alive with a large run of Chinook Salmon. 



A short time later the Oregon Fish Commission, feeling confident 

 that the electric screen was not responsible for the trouble at Gold 

 Ray and having information of similar conditions which had existed 

 upon several occasions in previous years, long before the installation 

 on any electric screen, sought information from the power company 

 as to the occurrence of short circuits in this system. These data, 

 covering a o-year period, were made available to the Oregon Fish 

 Commission, which in turn presented them to the Bureau of Fisheries 

 for their study. Seeking the best ]30ssible advice in this matter, the 

 Bureau of Fisheries retained Prof. F. O. McMillan, research pro- 

 fessor of electrical engineering, Oregon State College, to make a 

 thorough investigation of the situation, with special reference to any 

 possible effect which might have been produced by the presence of the 

 electric screen in the tailrace. After thorough study in the field and 

 conference with officials of the power company, Professor McMillan 

 reported under date of August 22, 1931 : 



I can assure you at this time that the findings are such that there is abso- 

 lutely no question in my mind but that the electric fish screen had nothing 

 whatever to do with the destruction of the fish that were killed. You will 

 probably recall that I have frequently called attention to the desirability of 

 having the electric screen entirely insulated, from the electrical system sup- 

 plying the power, by means of an insulating transformer, and that was the 

 condition of operation of the electric screen at the Gold Ray power plant at 

 the time of the electrical disturbances in question. During my investigation 

 in Medford I personally measured the insulation resistance of the fish-screen 

 transformer and of the conductors and cable supports for the electric screens 

 and found the insulation to be absolutely intact. This means tliat it would 

 be impossible for any of the ground current of the eleeti'ical system during 

 an abnormal electrical disturbance to flow back through the electric screen. 



In his comprehensive technical report, under date of October 4, 

 are set forth the indisputable findings, which show: 



(1) That the electrocutions of fish which occurred on April 16 and May 29 

 were due to ground currents existing through accidental single-phase opera- 

 tion of the 66,000-volt line No. 7 between Gold Ray power plant and Grants 

 Pass substation No. 2, these accidental single-phase operations occurring when 

 attempts were made to reestablish service on line No. 7 following line breaks. 



(2) That it was impossible for the electric screen to have conducted any 

 part of the ground currents, becau.se it was insulated from the electrical system 

 by means of an insulating transformer designed for the express purpose of 

 preventing any direct electrical connection with the supply system. 



(3) That the operation of the electric screen at the time of the accidental 

 grounds was probably responsible for preventing the destruction of a much 

 larger number of salmon than did occur. 



128210—32 4 



