ACTIVITIES AND OBSERVATIONS 



For 1 day, May 4, normal sequence of spill- 

 way gate operations was changed to detern-iine 

 riverflow patterns for future power generating 

 units. 



The waterflow was reduced in the right lad- 

 der from 11:00 to 11:30 a.m. and again from 

 1:30 to 3:40 p.m. on August 6 to repair a 

 broken chain on an adjustable weir. 



On August 30, attraction water was discon- 

 tinued at left ladder entrance at 10 a.m. for 

 removal of grass and weeds from the drop gate 

 screen. Water was restored to the attraction 

 system at left ladder entrance on August 31 at 

 2:30 p.m. 



On September 1, the center ladder was par- 

 tially dewatered from 12:45 to 2:30 p.m. to 

 allow inspection by a diver of the diffusion 

 gratings in the lower part of the ladder. 



On September 16, from 10:25 to 11:50 a.m., 

 attraction water at the left ladder entrance was 

 discontinued to allow a diver to cleain grass 

 and weeds from a large screen in front of the 

 drop gate. 



On September 20, the center ladder was 

 partially dewatered from 9 a.m. to 4 p.m. to 

 repair a broken chain on an adjustable weir. 

 An open submerged orifice was discovered at 

 bottom of the counting station weir. Fishpass- 

 ing through this opening were not counted. 



On September 21, the right ladder counting 

 station was out of operation from 6 to 10 a.m. 

 owing to high water in the pools above the 

 counting weir. This condition resulted from 

 grass amd weeds plugging the pickets at the 

 counting station. 



On October 1, the center ladder was par- 

 tially dewatered fronn 11 a.m. to 5 p.m. to re- 

 pair a broken chain on an adjustable weir. 



On October 5, the attraction water was dis- 

 continued at the center ladder from 10:20 to 

 1 1:40 a.m. to allow a diver to clean the screen 

 in front of the entrance drop gate. 



On October 15, attraction water at the left 

 ladder was discontinued from 10:00 to 11:30 

 a.m. during removal of grass and weeds from 

 the ladder entrance screen. 



As part of an evaluation study of effects of 

 Wanapum Dam reservoir encroachment on the 

 ladders at Rock Island Dam, the Bureau of 

 Commercial Fisheries trapped and taggedfish 

 at the left bank ladder. Chinook were taken in 

 a floating trap at the exit, and sockeye were 

 trapped at the counting station inside the lad- 

 der. All fish taken were tagged with numbered 

 Petersen disks and released about 1,000 ft. 

 (feet) below the dam in equal amounts on each 

 bank of the river. Trapping and tagging was 

 performed internnittently from May 16 through 

 June 9 for chinook and July 14 through August 4 

 for sockeye. During this period, 311 chinook 

 and 679 sockeye were tagged and released. 

 Numbers of tagged fish returning through the 

 ladders were: chinook, 288; sockeye, 626. 

 Twelve chinook tagged by fishery agencies in 

 the lower river were observed passing over 

 Rock Island Dam during the counting season. 



During 1965, fish were observed with cuts 

 or abrasions on their heads and bodies. Of the 

 85,107 salmon and steelhead seen passing over 

 the counting boards, 3,801 fish (4.5 percent) 

 had injuries (table 21). This was more than 

 twice the percentage of injured fish observed 

 in 1964. Because in both years the counters 

 could see only the top and one side of each 

 fish, the incidence of injury might have been 

 greater than observed. Of the total nun-iber of 

 injured fish observed in 1965, about 67, 22, 

 and 11 percent were recorded in the left, 

 middle, and right ladders, respectively. In 

 1964, these percentages were 56, 23, and 21. 

 As in previous years, the greatest number of 

 injuries was observed on the large chinook and 

 sockeye. In the 2-wk. (week) period July 16-31, 

 26,691 sockeye were counted through the fish- 

 ways and injuries were noted on about 8 per- 

 cent. In 1964, during the same period, about 2 

 percent of the sockeye observed had injuries. 



Throughout the counting season, State and 

 Federal fishery personnel made frequent in- 

 spections of fishway operations at Rock Islstnd 

 Dam. Inspections were similar to those at 

 other main stem dams where fishways were 

 operated. 



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