KEOKUK DAM 
111 
of two types. The type shown in Figure 14 gives a clearance of about 0.5 to 0.8 foot 
(15 to 23 centimeters) less than the other, but still large enough for any fish of the 
locality. It should be understood that the water passes smoothly and without com- 
motion through the turbines, so that a fish passing with the water would move rapidly 
but without being subject to any violent churning action. 
The wheel itself was examined as closely as possible. The blades or buckets 
appeared to come closest together at the top of the inner edge, where the aperture, 
as estimated, is 6 to 7 inches (15 to 18 centimeters) wide; this widens downward to 
about 10 or 12 inches; below is the river. 
After passing the screens in the head bay, a fish would nowhere find a narrower 
passage than the screens afford, except in one unit, where the vanes stand about 5 
inches apart. Probably a fish is trapped here occasionally, but it seems doubtful 
whether many fish go down through the turbines (p. 97); and the percentage, small 
enough to pass the 6-inch screen but too big for the 5-inch vanes, that chances to 
enter this particular unit must be negligible. 
EXPERIMENTS 
In an effort to learn whether fish are hurt at the base of the dam or elsewhere, 
Stringham allowed several fish to pass over the dam and others to go through turbine 
chambers. Three attempts in May and June, 1916, with paddlefish, goujon, and 
carp, respectively, were made by tying a line to the fish and attempting to draw it 
back, but in spite of modifications of method each time the three fish were lost because 
the line broke. The goujon was seen swimming before the line broke. 
On June 18 a carp 53 centimeters (21 inches) long and weighing 2 kilos (4% 
pounds) was dropped on the crest of the water of operative spillway 104, with a long 
line tied through its caudal peduncle, played out, and drawn back at another part 
of the dam; it was entirely uninjured and lively. On August 2 a carp 51 centimeters 
(20 inches) long and weighing 1.5 kilos (3/j pounds) was similarly dropped through 
spillway 105, a twisted cotton line (No. 90 or thereabouts) 116 meters (380 feet) 
long being used. The fish was drawn back alive but with scales scratched off each 
side of the back before the dorsal fin, the left opercle broken into four pieces, and 
the shoulder girdle partly severed from the body. 
On August 3 two carp, the smaller 56 centimeters (22 inches) long and weighing 
2 kilos (4 y 2 pounds) and the larger 81 centimeters (32 inches) long but not weighed, 
were fastened to ^-gallon buoys by lines each about 3 meters long, tied through the 
lower lips. They were dropped through spillway 106. The smaller was picked up 
below entirely uninjured. The larger was slightly scratched on the right opercle, 
and there was a little blood on each side under the base of the dorsal fin, but there 
was no abrasion. 
On August 24 three paddlefish, measuring 63 to 84 centimeters (25, 28, and 33 
inches), respectively, were dropped through spillway 42, similarly attached to buoys 
but with the line tied through the caudal peduncle. One became fast among the 
rocks but later floated free. The smallest was picked up dead but bore no marks. 
The other was uninjured, though there was a slight scratch at the base of the caudal 
fin, which may have been overlooked before the fish was dropped in. 
On August 27 several paddlefish, with pieces of cork from a life preserver tied 
to their snouts, were dropped into a whirlpool in the head bay of the power house, 
inside the screens; and, after passing through a turbine, one was picked up in the 
