inclusive) this condition was never clearly 

 demonstrated. 



Chief among the difficulties in pro- 

 ducing and maintaining a maximum entry was 

 our inability to provide an ample, sustained 

 supply of fish for the tests. A typical 

 entry rate achieved in the initial tests is 

 shown in figure 10. Depicted is the passage 

 of fish over the various weirs in the July 

 13 experiment. The entry into the fishway 

 is shown in the passage over weir 54. This 

 may be seen to rise rapidly to a peak (350 

 fish per minute) shortly after the release 

 and then decline almost as rapidly as it 

 had risen. At this stage of the investiga- 

 tions the assumption is that the supply was 

 not adequate to sustain a constant maximum 

 entry. Also, a major portion of the initial 

 supply would always be required to saturate 

 the fishway which was void of fish at the 

 start of a test. By the time a point of 

 saturation was being approached, the supply 

 had become virtually exhausted. Thus, it 

 was becoming apparent that the present 

 experimental condition of limited supply 

 was to be an obvious deterrent to a realis- 

 tic determination of capacity. 



Realization of the existing experimen- 

 tal limitations led us to conclude that our 

 initial approach to a determination of capa- 

 city would undoubtedly have to come from an 

 examination of conditions in the lower pools 

 of the fishway. This reasoning was beised 

 on the belief that the greatest surge of 

 fish would undoubtedly occur at the point 

 of entry into the fishway and that the lower 

 pools would be the first and perhaps the 

 only areas in the fishway which would become 

 sufficiently saturated for any period of 

 time. The approach may not appear to be in 

 keeping with our stated purpose of determin- 

 ing the maximum number of fish that a fish- 

 way can pass since passage implies that the 

 measure should be based on the exit from 

 the fishway (last pool). It is probable, 

 however, that capacity may in fact be con- 

 trolled at a particular point in the fish- 

 way, and that this point might well be in 

 the first pool or one of the lower pools. 

 Later in the text, data will be presented 

 which lend some support to this assumption. 



In the final test of the season (Sep- 

 tember 7) there is indication that a sus- 

 tained entry rate finally may have been 

 achieved. Figure 11 presents the numbers 

 of fish passing per unit time at 5 of 7 



lOOr 







WEIR 60 



WEIR 58 



WEIR 56 



WEIR 54 



Minutes After Release 



FIGURE 10. --PASSAGE PER MINUTE OVER WEIRS 

 54, 55, 56, 58 AND 60 DURING CAPACITY 

 TEST OF JULY 13, 1956. 



weirs in the fishway. Entry rate into the 

 fishway is given in the passage curve shown 

 at weir 54. The maximum observed entry per 

 minute was 75 fish and this occurred in both 

 the 2nd and 5th minute after release. From 

 the 6th to the 22nd minute, the entry held 

 relatively constant, fluctuating between 40 



14 



