second-feet. Picket barriers across one spillway gate adjacent to each of 

 the fishway entrances on the spillway dam also furnish attraction water for 

 the fishways. Each of these supplies approximately 3,000 second-feet of 

 water. 



Counting stations are located near the upper end of each ladder so 

 that the number of fish ascending may be counted (fig. U) . At each station 

 there is a picketed barrier in which is a 2-foot-wide opening through which 

 the fish can pass. A submerged white board is located under the opening as 

 an aid in identification of species. Before 1950, both counting stations 

 were at weir elevation 70. Early in 19^0 the Washington Shore counting 

 station was moved to the head of the ladder, where it is at headwater level 

 and where the fish, after being counted, pass directly into the forebay. 

 In 1951 the Bradford Island counting station was also moved to the head of 

 the ladder. 



In the design of the ladders no provision was made for the counting 

 stations. Their installation at weir 70 caused complications in adjustment 

 of the ladder. As there is no significant drop in water level at the count- 

 ing barrier, one weir, and hence 1 foot of elevation was lost. To provide 

 a large pool immediately below the counting station, a weir was omitted 

 there. Similarly to create a large pool above the counting station a third 

 weir was omitted. After 19h2, when the pool level xvas allowed to rise above 

 elevation 72, adjustments were made to compensate for the loss of 1 foot (of 

 a total of 3) of ladder elevation by adding 1; inches to the rise at the three 

 weirs immediately belo;-j the counting station. At normal forebay levels no 

 additional wfeirs were needed, but at the highest forebay level the 2 feet 

 lost through the eliminatif^n of weirs 70 and 71 had to be regained by increas- 

 ing the height of the v^eirs between the counting station and the upper end 

 of the fishway. 



The shad is considered a relatively unimportant species on the 

 Columbia Hiverj the fishways were constructed and are operated mainly for 

 the passage of the more valuable salmonoid fishes whose spawning grounds 

 are above the dam. A record is kept, however, of the miscellaneous species 

 using the fishways, and counts of shad passing up the ladders have been 

 made each year since 1938 when the fish-passing devices were completed. 

 As shown in table 1, the number of shad using all fish-passing facilities 

 at Bonneville Dam each year has varied considerably, from 2,8I|8 in 19ii3 to 

 9U}526 in I9I1.5 (U, S» Army, Corps of Engineers, 1950) , Shad have been counted 

 at Bonneville as early as May 13 and as late: as October 30, but the bulk 

 of the run usually passes the dam during the month of July. The one excep- 

 tion is the year I9I1O when a larger percentage xvas taken in June than in 

 July. 



