THE IRRIGATION AGE. 



241 



sary that the obstructions of the flow caused by the 

 observer's body shall not interfere seriously with the 

 current acting upon the meter. For large streams where 

 a structure is not available and where the water is too 

 deep or the current too strong for wading, a wire cable 

 is stretched across the stream and by means of a car 

 suspended from it the observer is enabled to make the 

 measurements at the various points in the cross-section. 

 Whatever be the means of spanning the stream, the first 

 thing the observer does is to stretch his tape, chain or 

 tag wire across the channel and divide the stream into 

 sections whose sides depend upon the accuracy of the 

 measurement desired. In Fig. 6 is shown the cross- 

 section of a natural channel with the tag wire stretched 

 and sections outlined as above suggested. The stream, 

 in this instance, is taken as being 100 feet wide and 

 ten foot sections have been chosen and represented by 

 the tags on the chain. Beginning at the left bank, 

 which is taken as station 10, the observer measures the 

 depth of water at the edge. Then the depth at five feet 

 is taken, which is assumed to be the average depth of 

 the first section. The center depths of the remaining 

 sections are then taken in successive order .and recorded 

 in the note book, in a column headed "Depths." Having 

 measured the depth of each ten foot section he next 

 proceeds to obtain the mean velocity of flow in the re- 

 spective sections. This, if the vertical integration 

 method is used, is done by taking observations at the 

 same points at which the depths have been measured. 

 He immerses the meter at Station 5, and waits until 

 the motion of the vane has become uniform and the flow 

 of the water undisturbed, then simultaneously with the 

 sound of the buzzer the stop watch is started and the 

 meter gradually lowered until it reaches the. bottom of 

 the channel, then changing the direction it is moved 

 upward with a uniform motion until the starting point 

 is reached. The observer continues this vertical motion 

 usually for fifty seconds. The fifty second period is 

 chosen for ease in computation of the results. To deter- 

 mine the number of revolutions per second made by the 

 vane where the fifty second period is used it is only 

 necessary to multiply the total number of revolutions by 

 two and point off two decimal places. The number of 

 revolutions made at the center of each section is recorded 

 in the note book as shown. This completes the notes 

 of the observation and they are now ready for computa- 

 tion. 



GAUGING OF GALLATIN RIVER AT SALESVILLE, MONT. 



Date June 3, 1902. Gauge Height 7.4. 



Revolu- 



Station Depth Time tions 

 10 Left Bank 



Revolutions 



per Dis- 



Second Velocity Area charge 



110 Right Bank 



794.7 

 Meter No. 112. 



PAGE OF FIELD NOTE BOOK. 



Computation of field notes. The figures in the first 

 four columns represent the observations taken in the 



field. In column headed "station" are given the points 

 in the cross-section at which the depths of sections re- 

 corded in the second column and meter observations 

 recorded in the fourth column have been taken. In com- 

 puting the discharge, the number of revolutions made 

 per second by the meter are placed in the fifth column. 

 From the rating table of the meter a mean velocity of 

 flow for each section corresponding to the revolutions 

 per second observed are placed in the sixth column, 

 headed "velocity." The width of each section in the 

 case under consideration is ten feet. This multiplied 

 by the mean depth of each section gives the area in 

 square feet, which is placed in the seventh column. Not 

 knowing the area and corresponding mean velocity of 

 each section, the product of the two gives us the dis- 

 charge, which is placed in the last column. The sum 

 of the several discharges is the total discharge of the 

 stream. The method of recording notes varies, of 

 course with the style of meter used and with the way in 

 which the velocity is determined. 



From what has been said, it will be seen that the 

 accuracy of current meter measurements depends pri- 

 marily upon the accuracy of the meter rating. It also 

 depends upon the care and the manner in which the 

 meter is used and upon the conditions of flow in the 

 channel measured. Other conditions being equal, the 

 best results will be obtained where the measurement can 

 be made in the section of greatest uniformity. For this 

 reason, the rating flume should be used wherever pos- 

 sible and wherever a record is to be continued on a canal 

 or stream some means should be adopted to obtain a 

 uniform fixed channel. In a few of the Western States 

 laws require that all irrigation canals and ditches shall 

 install properly constructed rating flumes near their re- 

 spective points of diversion. 



KANSAS VS. COLORADO. 



Senator Smith Spoke of the Law-suit and What It Means for 

 Kansas. 



At the irrigation convention held at Garden City, 

 Kan., in December, Senator F. Dumont Smith, of Kins- 

 ley, one of the counsel for Kansas in the suit of Kansas 

 vs. Colorado, explained the objects and status of the 

 case. This suit was brought by the State at the urging 

 of the people in the Arkansas Valley around Wichita 

 and Arkansas City, who believed that since the exten- 

 sive practice of irrigation in Colorado the water in the 

 Arkansas and the underflow was greatly decreased. 

 Such a case is unprecedented. The contention of Kan- 

 sas is under the old common law doctrine of riparian 

 rights, that the lower properties on a stream had a 

 right to have the water flow as accustomed except for 

 domestic use, the proprietor above not being allowed 

 to prevent or contaminate the water. The Colorado 

 contention conceeds the common law position of Kan- 

 sas but holds that owing to necessity this principle has 

 been superseded in arid regions by the theory of prior 

 appropriation, that the man who first takes out the 

 water for irrigation" has the first right to it. This 

 doctrine prevails in all the Western States and is recog- 

 nized by the constitution of Colorado, and was agreed 

 to by the United States when Colorado was admitted 

 with that constitution. Under this theory Colorado 

 claims the right to every drop of water in the river. 

 Colorado further claims that irrigation in that State 

 does not injure Kansas, 



