4 
Colorado Experiment Station 
According to ex-State Engineer, John E. Field, the above law, which 
was passed in 1874, was drafted to meet the conditions under which irri¬ 
gation water was being measured at that time in the vicinity of Denver. 
A box made of boards 16 feet long was placed through the ditch bank, and 
it was given a grade of at least one-eiglith of an inch to the foot. If the 
irrigator had a water-right of 3 6 inches, the box would be made 6 inches 
square, inside measurement, and for 60 inches, it would be made 6 inches 
deep by 10 inches wide. It is interesting to note that although the law 
was intended to apply to the flow through such tube-boxes, it is so worded 
that it applies to practically all types of inch devices. Very few tube- 
boxes are used in Colorado now, nearly all inch measurements being made 
through thin edged orifices placed in the vertical side of a box so the is¬ 
suing stream of water flows free into the air. 
Former State Engineer, Nettleton, computed the flow through an 
orifice to correspond to the Colorado law, and stated the quantity to be 
1 y38.4 of a cubic foot per second. This value has been assumed to be 
the value of the Colorado “Statute Inch." 
In order to secure definite information concerning the Colorado 
statute inch a series of experiments were made in the hydraulic labora¬ 
tory, at Fort Collins, Colorado, during the fall of 1914 and the spring 
of 1915. The results of these experiments are given in the tables in this 
bulletin for the use of engineers and others who may have need of. the 
actual data. Experiments were also made with one type of measuring de¬ 
vice used in the Uncompahgre Valley, and with one of the Miner’s Inch 
devices used in Southern California known as the Azusa hydrant. 
COLORADO STATUTE INCH. 
Box-Tubes.—Many of the water rights in Colorado are stated in 
inches, though there are but few irrigation systems in the state under 
which the water is actually measured in inches. The water is usually 
measured in second feet, but it is necessary to know the quantity of water 
that will flow through orifices under the terms of the Colorado law in 
order that the irrigator may receive the amount he is entitled to. 
In reply to an inquiry concerning the method of installing the outlet 
or tube-box, Mr. John E. Field gave the following description of the 
practice of 30 or 40 years ago. “In the earlier practice it was seldom 
that an effort was made to regulate the head over the outlet boxes. Where 
this effort was made, it was by means of a box or long-crested weir which 
would discharge back into the ditch the surplus water entering the box. 
This box or flume was placed parallel to the bank of the ditch and the 
outlet box was placed at the lower end. This did not regulate the head 
absolutely, but only approximately. Where this method was not used, 
the boxes were placed so that when the ditch was at normal stage there 
would be a 5-inch pressure. When there was a greater amount of water 
in the ditch, then the discharge through the box was greater, and when 
it was less it was in the nature of cutting down the amount purchased 
and a rough pro-rating of the available amount. When the ditch was 
very low this pro-rating was done by shutting down the boxes partially, 
