GATE STRUCTURES FOR IRRIGATION CANALS. 27 
PROPORTIONAL DIVISION BOXES. 
In parts of Utah and northern Colorado and in other places in the 
West a type of structure is used which is supposed to divide what- 
ever water there is in a ditch in a proportional manner. As a rule 
this division box is used on rather small ditches, owned by a few 
men as partners or a small group of men organized as a cooperative 
company. The general manner of division is the same in either case. 
Assume the organization to be a small cooperative company in which 
a share of stock entitles the holder to the same proportion of what- 
Fig. 5. — Wooden division box, Montana. 
ever water is turned into the ditch as one share bears to the total 
number of shares in the company. Assume the total number of 
shares of stock to be 36 and that the first stockholder on the ditch 
has 11 shares and the second one 8 shares. The first division box, 
therefore, is to turn out eleven-thirty-sixths of whatever water is in 
the ditchy and the second box is to turn out eight-twenty-fifths* of 
the remaining water. The denominator becomes 25 for the reason 
that after delivering water to the 11 shares the water remaining in 
the ditch represents 36 less 11, or 25 shares. This procedure is car- 
ried out to the end of the ditch. 
