Table 3. — Species composition of group releases ascending the half -width and full -width Ice 



Harbor fishway, June 8 to September lA, 1960 



Test 

 condi- 

 tion 



Date 



Species coinposition 



Chinook 



Chinook 

 jacks 



Steel- 

 head 



Sockeye 



Non- 

 salmonids''" 



Half -width fishway 

 Test l2 



Test 2 



Test 3 



Test <4 



Test 5 



Test 6^ 



Test 7^ 



Full -width fishway 



Test 1 



Test 2 



Test 3 



Test A 



Test 5 



Test 6 



June 13 



July 28 



July 29 



Aug. 3 



Aug. 5 



Aug. 12 



Sept. U 



June 8 



June 9 



June 10 



June 24 



Aug. 9 



Aug. 10 



Percent 



'•■90.0 

 *90.0 



15.0 

 9.6 



10.4 

 4.7 

 4.9 



12.3 

 23.2 



*97.6 

 *94.6 

 *91.5 

 *77.4 

 1.0 

 2.8 



Percent 



.7 

 2.5 



3.1 

 1.4 



2.0 

 1.4 

 2.5 



Percent 



7.5 

 7.5 



*77.5 



*87.6 



*75.2 



*92.0 



*88.9 

 *97.9 



*82.8 

 *69.6 



5.4 



8.5 



7.4 



»96.6 



*93.3 



Percent 



Percent 



2.4 



13.2 



1.0 

 1.4 



■'" Includes suckers ( Catostomus sp.] 

 ( Cyprinus carpio j . 



squawfish (Ptychocheilus oregonensls) ^ and carp 



Both sides of the divided fishway tested simultaneously. 

 ■H-Dominant species . 



These performances compare favorably with 

 those in the group tests of June 13 (table 4) in 

 which the median elapsed times for sample 

 sizes of only 40 fish were 8.8 and 8.2 minutes, 

 respectively. Capacity tests in late July and 

 early August prinnarily used steelhead trout 

 of sample sizes considerably larger than those 

 in the June tests (table 5). Passage tinnes in 

 the midsunnmer tests are not directly com- 

 parable with those in the earlier tests because 

 of differences in season, species composition, 

 and weir crest design in the two sets of tests. 

 The general performance of fish in these 

 tests showed that they moved freely through 

 the fishway. The number of fish during these 

 tests was apparently insufficient to approach 

 a capacity condition in the fishway. 



Effect of Weir Crest Design 



The original Ice Harbor fishway design spe- 

 cified The Dalles-type weir crests, but in our 

 studies we noted that this crest produced an 

 air pocket beneath the nappe of the overfall. 

 As there was son-ie concern that this condition 

 might innpede the passage of fish, we also 

 studied the effects of two other shapes of weir 

 crests, the McNary type and the plane-surface- 

 ogee type (fig. 4). We connpared passage times 

 of fish under various weir crest conditions 

 (table 6). 



The McNary crest appreciably reduced the 

 objectionable air space and provided a 

 smoother overfall and a less turbulent flow 

 pattern in the pools (fig. 15). Fish passage 



11 



