GATE STRUCTURES FOR IRRIGATION CANALS. 



47 



height the permanent gate should reach, and it can be designed 

 accordingly. If concrete is used in the beginning, then it is difficult 

 to add to the height without great expense and a patched appear- 

 ance, and if the structure is already too high, then the extra material 

 is wasted. 



Most checks are for the sole purpose of controlling the level of 

 the water above the structure, and the question of tightness does not 

 enter into their design. However, if for any reason it is desired that 

 all the water be stopped at a check and delivered to a side gate, then 

 the shutters must be made tight by closer joints, tar or other roofing 

 paper, or in some such manner. 



Fig. 13. — Concrete check, lateral headgate or delivery gate, Sacramento Valley Irrigation 



Co., California. 



CHECK GATES, SACRAMENTO VALLEY IRRIGATION CO., CALIFORNIA. 



The Sacramento Valley Irrigation Co. has adopted a set of stand- 

 ard plans which may be used in many other parts of the West. The 

 check-gate structure shown in figure 13 can be used also as a lateral 

 headgate or a delivery gate. In fact this is done by the simple L 

 construction which is so well adapted to a combination of check 

 and delivery. The general construction of this gate is adapted 

 either to flashboards or a stem gate. The latter is used most com- 

 monly by this company. As shown on the detail view in Plate I, i, 

 this stem permits of holes through it far below the top of the shutter 

 without causing leakage through the latter, and it is not necessary 



