AN UNSOLVED WESTERN PROBLEM. 



THE DIVISION OF THE WATERS OF INTER-STATE STREAMS. 



BY ELWOOD MEAD. 



PWO reasons influenced the selection -of this topic. 



J The first was the belief that the opinion of the 

 irrigator at the head of the stream is always of inter- 

 est to the user of water below. The second was the 

 conviction that the division of water across State 

 lines is destined to be a live question in the near fut- 

 ure. As population increases and the area of land 

 reclaimed is extended, the demands on some streams 

 will exceed the supply, and parties living below the 

 invisible barrier which the boundaries of a common- 

 wealth interposes will seek some method of setting it 

 aside. Already parties having investments on the 

 lower levels of inter-state streams look with extreme 

 and anxious disfavor on continued diversions across 

 the border above them. A few controversies have 

 already arisen in which the aid of the courts has been 

 invoked, and the subject will inevitably become a dis- 

 astrous source of litigation unless satisfactory methods 

 of division can be secured. The settlement of inter- 

 state rights in the courts would be enormously expen- 

 sive, and could not but prove unsatisfactory because 

 the relief would be wholly inadequate. The division of 

 water is not accomplished by a court decree. There 

 must be in addition some administrative authority 

 and action. When the floods come all users must be 

 permitted to reap the benefit, and when they subside 

 those entitled to the water must be protected in their 

 rights. Nor are the courts the proper tribunal for 

 the determination of the questions involved. The im- 

 portant problems, or rather the difficult ones, are not 

 legal but physical. Any economical or satisfactory 

 distribution of water must take into account the 

 character of the discharge under original conditions 

 and the modifications produced by use in irrigation. 

 The duty of water, the losses from percolation and 

 evaporation, must all be studied. Courts have no 

 personal familiarity with this subject, and it will be 

 little less than a calamity to intrust the important in- 

 terest involved to the hazard of their decision. It is 

 important, therefore, that those interested in this 

 question give it early and careful consideration in 

 order that when relief becomes imperative the 

 method of procedure may be prepared. It is the aim 

 of this paper to present some problems which con- 

 front the attempt to provide a system of supervision 

 for inter-state streams. 



These problems are both physical and political. 

 They will be considered in the order of their state- 

 ment. 



In the first place the conditions of each stream 

 should be carefully studied in order that the effect of 

 diversions above on the volume below may be de- 

 termined. A blind adherence to priority numbers is 

 not the rule in state supervision and should not be 

 in inter-state. The use of water in high level canals 

 does not necessarily mean a loss to the users of 

 water below. On the contrary it is, within certain 

 limits, a marked advantage. It may, and unquestion- 

 ably does, diminish the total discharge, but it at the 

 same time increases the available supply. It holds 

 back the spring floods when there is a surplus and 

 augments, through percolation, the supply in seasons 

 of scarcity. 



The fluctuations in the discharge of the streams 

 leaving the Rocky mountains do not coincide with 

 the variations in the use of water for irrigation. 

 There is a surplus early in the season and a short- 

 age at the close. The area of land which these 

 streams will serve is not determined by the discharge 

 at flood time in June, but by the supply for July and 

 August. This is fully appreciated in irrigated dis- 

 tricts, but is not generally understood elsewhere. An 

 examination of the gauging records of a number of 

 inter-state streams shows that the average discharge 

 for August is only from one-seventh to one-tenth that 

 of June, while from one-third to one-fourth as much 

 water is required for irrigation in the latter month 

 as in the former. What is needed, therefore, is 

 some provision for holding back the surplus of May 

 and June for the period of scarcity later on. So 

 long, therefore, as diversions above do not result in 

 diminishing the discharge in the season of scarcity 

 below what it would have been under original condi- 

 tions, appropriators below cannot be considered as 

 being injured, and this holds good under all condi- 

 tions as regards priority of appropriation. 



This fact is taken into account in the division of 

 water within state lines. Subsequent appropriators 

 living at the head of streams are encouraged to use 

 all the water possible in the early part of the season, 

 and in no case are the head gates of the upper 

 ditches closed until the rights of prior claims below 



