THE IRRIGATION AGE. 



41 



The Importance of Water Measurement 

 and Accurate Records of Delivery* 



By Samuel H. Lea, State Engineer of So. Dak. 



One of the most important problems that con- 

 fronts the irrigation manager comprises the perfec- 

 tion of a method of delivering water that shall insure 

 to the water user adequate returns, while making 

 the greatest possible use of the available water supply. 



The economical use of irrigation water is es- 

 sential for obtaining the best results, that is where 

 the net duty represents the best use of water. This 

 is the case when only sufficient water is applied to 

 give the best crop production and when the losses 

 of percolation and evaporation are eliminated as much 

 as possible by a skillful application of water and 

 proper cultivation. 



The necessity for using our water supply with 

 due regard to economy is apparent to us all, and we, 

 realize that the situation is becoming more acute with 

 the passage of time. 



In the west there are vast areas of irrigable land 

 awaiting agricultural development, for which there is 

 only a limited supply of water. Of necessity, the 

 available water supply must be used economically, so 

 as to bring the largest possible acreage under the 

 ditch. 



It is universally conceded that the wasteful use 

 of irrigation water results in overirrigation and con- 

 sequent injury to crops as well as damage to the land. 

 In the irrigated west there are hundreds of thou- 

 sands of acres of land that have become waterlogged 

 because of excess of water. While it is true that such 

 excess is not entirely due to over irrigation, since a 

 large percentage comes from seepage losses in ditches, 

 still a considerable portion of it is due to wasteful use 

 of water. 



Another reason why irrigation water should be 

 economically used is that better crop results are ob- 

 tained where careful use is made of the water. Re- 

 ports of the United States Office of Irrigation In- 

 vestigations show conclusively that better crop pro- 

 duction is obtained where just sufficient water is ap- 

 plied, than where a larger quantity is used. By eco- 

 nomical use is meant making the available water 

 supply go as far as possible, using only what is neces- 

 sary to produce maximum crops without wasting the 

 water or supersaturating the land. It is admitted that 

 this is an ideal condition, requiring much patient effort 

 to bring about, but still not unattainable. 



We are all aware of the common tendency to 

 waste water by users, and we also are more or less 

 familiar with the water hog who infests irrigated sec- 

 tions. We are, doubtless, all agreed that the waste- 

 ful use of water under present irrigated methods is a 

 condition to be deplored and for which some remedy 

 is required. 



Until within a comparatively recent period irriga- 



*Paper read at meeting of Irrigation Managers U. S. 

 Reclamation Service, Ft. Collins, Col., Dec. 5-6, 1912. 



tion methods were but little different from those fol- 

 lowed by water users of ancient times. For cen- 

 turies there was very little advance in methods of 

 applying water for crop production. Fertile valleys 

 were made into swamps by wasteful methods of 

 handling water, and the duty of water was reduced 

 to an unsatisfactory minimum. 



We have now advanced to the point where better 

 results are demanded in the way of water transmis- 

 sion and storage as well as in the net duty of water 

 for irrigation. Modern conditions demand a more 

 intelligent use of water in irrigation operations, and 

 in order to accomplish this we must regulate the 

 water supply so as to furnish the proper quantity 

 without waste or unnecessary loss. 



The most feasible way to bring about the desired 

 result in fairness to all is to measure the water used 

 and to keep accurate records of its delivery to con- 

 sumers. 



On the large irrigation projects and as the water 

 becomes more valuable, it is of increasing importance 

 to keep systematic records covering the discharge of 

 the main canals and laterals, the water lost by seep- 

 age and evaporation and the water returned to stream. 



It is also important to determine the approximate 

 quantity of water delivered to each tract of land. It 

 is desirable to have in addition, the acreage in each 

 crop and the yield per acre for the individual water 

 users. With these records the irrigation manager is 

 in a position to introduce important economics in 

 handling the water, reduce water losses, and he can 

 meet complaints of water users with the facts as to 

 actual quantities of water delivered between given 

 dates. 



By measuring the water and keeping a record 

 of its delivery an effective means is provided for de- 

 termining losses in transmission through canals and 

 supply ditches. In many cases, where seepage losses 

 are excessive, it may be found advisable to prevent 

 these by using an impervious lining for the ditch, 

 thereby saving valuable water. Where costly diver- 

 sion works have been constructed it is reasonable to 

 expect that the water supplied at headgate should be 

 delivered without serious loss. 



In the distribution of irrigation water contracts 

 are frequently made on an acreage basis. So long as 

 users are permitted by their contracts to take all the 

 water they consider necessary to irrigate an acre of 

 land there can be no economy in the use of water, for 

 whenever there is a full ditch, those under it will en- 

 deavor to use as much as possible for their respective 

 needs. 



Many engineers claim that the only way in which 

 water can be economically used is to measure out the 

 quantity to which each user is entitled and permit 

 him to make the best possible use of what he has pur- 

 chased. If it is to the interest of water users to save the 

 water which they receive from the ditch, the water 

 now used and wasted on western lands will be suffi- 

 cient for a much larger area. 



The following argument in favor of the recorded 

 measurement of water is advanced by an eminent hy- 

 draulic engineer: 



First, metered service pleases the economical con- 



