14 



ARTIFICIAL, PROPAGATION OF PACIFIC SALMONS. 



turn in eyebolts in the side walls. To pre- 

 vent the fish passing through when the gate 

 is open, a 12-inch board should be nailed 

 across its under side at such an angle that 

 the current rushing against it will lift the 

 lower end of the gate just above the surface 

 of the water. Floating objects coming 

 down the stream are carried onto the gate, 

 which sinks from their weight, and as the 

 current carries the object on the gate closes 

 automatically. 



Eacks constructed in accordance with 

 this method will often stand submerging 

 several times in the course of a spawning 

 season, and at its close remain practically 

 undamaged. 



A barrier that has stood the test of sev- 

 eral years and has proved that it will oper- 

 ate successfully in almost any stage of 

 water is described in the following para- 

 graphs.'* The design is to be credited to 

 A. H. Dinsmore, former superintendent of 

 the Baker Lake (Wash.) station. 



A permanent barrier at the Birdsview station, 

 an auxiliary of ttie Baker Lake station in Wash- 

 ington, is of novel construction and calls for 

 more than passing notice. This barrier is located 

 in a portion of Phinney Creek, where formerly 

 there was a dam built for the purpose of obstruct- 

 ing the passage of steelhead trout. When the 

 dam washed out, a new channel formed and the 

 river bed was very much broadened. 



The first step in the construction of the new 

 barrier was the laying of four heavy log stringers 

 acros.s this new channel from the abutment on the 

 north to the new bank on the south side of the 

 stream. The logs were let down through the dam 

 foundation to low-water level on the north side, 

 and the deep channel under them on the south side 

 was filled with brush and gravel. The logs were 

 spotted down to form a practically level bed, 

 reaching the width of the stream. Heavy piles 

 were then driven behind each stringer to form 

 alternate single and double rows extending up and 

 down stream. The log stringers were next 

 I)lanked over, forming a platform 18 feet wide, 

 similar to a regular dam apron, extending from 

 the north abutment to the final row of piles on the 

 south side, a distance of about 140 feet. 



By planking the sides of the single row of piles 

 and all around the double rows and filling the 

 space with rocks, piers 4 feet high and approxi- 

 mately 2 feet and 4 feet wide were formed. 

 Through each pier at the bottom, behind the 

 upstream pile, openings 1 foot square were left, 



" Titcomb. .Tohn W. : Fish-cultural practices in the 

 Bureau of Fisheries. Bulletin. U. S. Bureau of Fish- 

 eries, Vol. XX VIII, for 1908, part 2, pp. 728-732. 

 Washington, 1910. 



