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BULLETIN 115, U. S. DEPARTMENT OP AGRICULTURE. 



ply canal for the larger of the two canals and change the direction 

 of the smaller channel. This involves about the same construction 

 as a check gate and a lateral delivery, the check serving as the head 

 gate of the larger of the two divisions and the lateral gate as the 

 head gate of the smaller division. 



The relations between the two companies receiving water from a 

 structure of this class may be such that the designer is called on to 

 attach locking devices to either or both of the division gates. This 

 condition may involve a more expensive form of gate shutter than 

 would be required if the water is to be divided between two canals 

 of the same organization. 



BIFURCATION GATES, HOLBROOK IRRIGATION DISTRICT, COLORADO. 



About 9 miles below the head of the Lake Canal of the Holbrook 

 irrigation district, in Otero County. Colo., the inlet canal to supply 



Side Elevation- Inlet. 



Fig. 3. — Bifurcation works on Lake Canal, Holbrook irrigation district, Colorado. 



Dye Reservoir leaves the main canal. The regulation of water 

 between these two is effected by means of the twin structure shown 

 in Plate VI, figure 2. This structure illustrates very well the 

 general practice in Colorado of combining wood and concrete. It 

 is noted that the wings, floor, and side walls are of concrete, while 

 the gate shutters — shown in detail in Plate I, / — the front guides, 

 and the whole bridge structure are of wood (fig. 3). As these parts 

 are all bolted to the concrete they may be replaced as they rot out, 

 whereas the portions most difficult of access are made permanent. 



The canal leading to the structure is 30 feet wide on the bottom, 

 7 feet deep at the water line, and has a capacity of 1,000 second-feet. 



