Figure 12. — Grills prevented orifice passage of fish at weir 54. All fish entering 

 fishway passed over weir crest where they could be observed. 



In capacity-type tests, fish were collected 

 for about 48 hours prior to a test. The collec- 

 tion pool brail was partially raised to con- 

 centrate fish near the surface of the pool 

 immediately before the test started. A large 

 entry gate between the release boxes was then 

 opened; it provided access to the fishwayfrom 

 the collection pool. These tests used only half 

 of the fishway. At the upper ■weir, special ob- 

 servers identified the species. 



Timing of fish . --An electrically driven 

 operations recorder recorded the movement of 

 fish as they ascended the fishway. Each time a 

 fish passed a station, the observer depressed 

 a button switch, which in turn activated a pen 

 that scribed a mark on a time-event chart. 

 Chart records were translated to passage times 

 and recorded on a daily operations sheet. 



Individual fish were timed as they entered the 

 fishway at weir 54 and as they left it at weir 60. 

 Since grills cover the orifices at weir 54 (fig. 

 12), each fish crossing this weir could be ob- 

 served. At weir 60, observers above the weir 

 noted fish passing the crest, and those in the 

 observation chamber observed their passage 

 through the orifices. A test run was completed 

 after the fish either had ascended the six pools 

 of the fishway or had remained in the fishway 

 for more than 1 hour without being observed. 



During group and capacity tests, counters 

 at weirs 54 and 60 kept a time-event record of 

 all fish entering and leaving the fishway and 



also noted all "fallback activity." Time inter- 

 vals of the group test periods varied, depending 

 on the willingness of fish to ascend the six- 

 pool fishway. Tests terminated either when 

 all fi^h' had passed through the fishway or 

 ■whetT only a few slow-moving individuals re- 

 mained in it. Capacity tests lasted 1 hour. 

 The entrance gate closed 30 minutes after the 

 start of a capacity test, but observations and 

 counting continued another 30 minutes. 



Comparison of Passage Times 



Both median and mean passage times were 

 used to compare performance of individual 

 fish under various test conditions. Median 

 times were based on all fish tested, including 

 those individuals that spent more than 1 hour 

 in the fishway without completing the six-pool 

 ascent, whereas mean passage times were 

 based only on these fish that completed the 

 ascent. A table of confidence intervals (Dixon 

 and Massey, 1957) was used to test for dif- 

 ferences between median passage times of 

 various tests with individual fish. 



For group and capacity-type releases, a 

 statistic called "median elapsed time" was 

 used to assess performance. This was derived 

 by subtracting the time at which half of the 



Fish that drift or swim back over a weir or through 

 an orifice. 



