Installation of electrical sea lamprey 

 barriers in 1952 



In general, a practical, economical electrical device for 

 blocking and/or capturing migrant sea lampreys was evolved from the 

 experimental electromechanical weir operated in the Ocqueoc River in 

 1951* Using 2-inch diameter tubes as electrodes arranged on U-foot 

 centers in a diamond pattern it was determined that migrant sea lam- 

 preys could be blocked and/or diverted (or destroyed within the array) 

 if a minimum voltage gradient of 0. 75 volt, AC per inch was esta- 

 blished on a line between the center and upstream rows of electrodes. 

 Such a minimum gradient between the above named rows of electrodes was 

 conveniently obtained at a 110 volt input to the array. The device 

 functioned effectively on very small amounts of power at common line 

 power voltages or simple reductions of these voltages. 



In view of the low power requirements of the device , ela- 

 borate experimentation directed particularly at further reducing said 

 power requirements was not undertaken during the 1952 season. However, 

 experiments directed at reducing the amount of physical equipment re- 

 quired in a given device could and did result in reductions in power 

 demand. It was further deemed of no immediate practical advantage to 

 engage in experimentation that would lead to the use of some odd input 

 voltage level requiring special or additional transformers, etc. (e. g., 

 indiscriminate and arbitrary changing of electrode spacing and array ~ 

 pattern, particularly in the upper half of incremental fields, for pur- 

 poses other than to compensate for varying electrode diameter and effi- 

 ciency) . Reductions in numbers and rows of electrodes and changes in 

 electrode systems were accomplished where swift water velocities occurred 

 at test sites but experimentation was not carried beyond the point where 

 input voltages greater than 110 would be required to block or divert the 

 migrant lampreys. 



The four pilot model alternating current devices installed in 

 1952 were designed primarily; To demonstrate the practicality and econ- 

 omy of this type of sea lamprey control device j to provide suitable facil- 

 ities for improving the mechanical design of the device sj and, to permit 

 investigations of various power supply problems. Because the experiments 

 of the preceding year had brought out rather clearly many of the major 

 electrical characteristics of an effective barrier, it was considered 

 necessary to provide only limited flexibility in the 1952 installations 

 for experimentation of an electrical nature. These structures were de- 

 signed primarily with a view toward mechanical flexibility adequate for 

 the solution of certain problems of construction and installation that had 

 been raised by the previous years experience. Further information on 

 mechanical problems was obtained by variation from device to device in 

 the structural components. 



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