Figure 3. — Six-pool test section of the 1-on-lO-slope Ice 

 Harbor fishway design. Divider panels Inserted for 

 optional testing under a half-width condition. 



»— FLOW 



V4' CHAMFER — H [•— I W*' 



^ 7 — ^— iM' CMUim 



5 W»' 



v^ ^^ 



THE DALLES 



PLANE-SURFACE 0«EC 



Figure 4. — Sectional views of types of weir crests. 

 ^OIVIDCR WALL 



L, _-, 



PLAN 



— I T '■-• 



TT- i I i i 



Weir crest design . --Three types of weir 

 crests were used in the tests (fig. 4). The 

 original design specified The Dalles-type 

 crest, but to eliminate certain undesirable 

 characteristics of the overfall, we tested two 

 other types of crests, the McNary and plane- 

 surface ogee. 



Hydraulic conditions .- -The normal head on 

 weirs, measured 4 feet upstream of the weir 

 crest, was 0.95 foot, which produced a fishway 

 flow of about 63 cubic feet per second (c.f.s.). 

 Velocities during normal operation ranged 

 from about 1 foot per second (f.p.s.) on the 

 surface to about 8 f.p.s. in the center line of 

 the orifices. Metering stations (fig. 5) indicate 

 the points at which velocity readings were 

 obtained in pools 57 and 58 of the half- width 

 fishway. Velocity plots during normal flows 

 (fig. 6) and experimental flows (figs. 7 and 8) 

 were taken with a cup-type current meter in 

 the left bank of the divided fishway. 



Experimental flows included: ( 1) Overfall and 

 orifice flows with 1.20 feet of head on weirs, 

 (2) overfall flows only (no orifice) with 0.95 

 foot and 1.20 feet of head on weirs, and 



TOP OF WEIR 



MID-DEPTH 



CENTER LINE OF ORIFICE 



Figure 5.--Meterlng stations in the test fishway pool 

 divided at center line. Dotted lines In plan view indicate 

 additional metering stations at center Line (elevation) of 

 orifices only. 



(3) orifice flow only (no overfall flow) with 

 1.0-foot head on the orifice. When orifices 

 were closed, 0.95-foot head on weirs produced 

 a plunging"^ flow, but streaming' flows re- 

 sulted when the head on the weirs was increased 

 to 1.20 feet. 



In a plunging flow, the strong airectlonal flow carries 

 downward and along the bottom of the pool. 



' A streaming flow condition produces a strong direc- 

 tional flow along the surface of the pool. 



