LIST OF ILLUSTRATIONS 



Figure Page 



1. Experimental electromechanical weir and trap installed 



in the Ocqueoc River in 195l 2 



2. Plan and block diagram of experimental electromechanical 



weir and trap installed in the Ocqueoc River in 195l 3 



3. Electrical circuit diagram of experimental electromechan- 



ical weir and trap installed in the Ocqueoc River in 



1951 5 



U. Drawing of ground-mounted electrode and stake assembly 6 



5. Electromechanical weir and trap installed in the Kewaunee 



River in 1952. 12 



6. Drawing of electromechanical weir and trap installed in 



the Kewaunee River in 1952 13 



7. Electrical block diagram of electromechanical weir and 



trap installed in the Kewaunee River 15 



8. Electromechanical weir and trap installed in Squaw Creek 



in 1952 17 



9. Electrical barrier installed in Hibbards 1 Creek in 1952 18 



10. Electrical barrier installed in Carp Creek in 1952 with 



upper and lower checking weirs 19 



11. Drawing of electrical barrier installed in Carp Creek in 



1952 20 



12. Electrical block diagram of electrical barrier installed 



in Carp Creek 22 



13. Observer recording behavior of fish and lampreys below 



and within the electrical fields in the water 23 



lU- Checking voltage gradients within electrode array with 



probe and vacuum tube voltmeter 25 



15. Drawing of voltmeter probe 26 



16. Drawing of water and stream-bed resistance probe 28 



17. Relationship of total immersed electrode surface and 



power consumption l|2 



18. Drawing of recommended design of multiple-row, suspended 



electrode, electromechanical weir and trap. 1|6 



19. Drawing of recommended design of electrical barrier or 



electromechanical weir and trap with single-row, 



suspended electrodes and ground line U8 



20. Diagrammatic plan of recommended design of electrical 



barrier consisting solely of two lateral submerged 



electrodes. U9 



