IRRIGATION INVESTIGATIONS. 421 



of depth of water at an\ v point. Efforts have been made to cheapen 

 these instruments and at the same time increase their efficiency. Little 

 has been accomplished with the current meter, but the water register 

 has been so simplified as to reduce its cost by more than half without 

 any sacrifice in accuracy. The appearance and method of using these 

 registers is shown in PI. XXXIX. 



LEGAL AND SOCIAL PROBLEMS. 



The measurements made to determine the quantities of water used 

 and the losses from canals has another object besides the improvement 

 of agricultural practices. It is a principle of irrigation law, in theory 

 at least, that rights to water ,are based on beneficial use; that is, a 

 person or company can maintain a right to only so much water as he 

 or it can put to a beneficial use in irrigation. It is of first impor- 

 tance, therefore, to know how much water is needed to grow crops on 

 a given area, in order that courts and boards of control may intel- 

 ligently determine the amount of rights to water, and officers charged 

 with this duty be able to prevent wasteful use by those who have early 

 rights or a desire to monopolize the supply. Because of the lack of 

 this information, rights to water have too often been established with- 

 out any regard to the volume of the stream, the capacity of canals, or 

 the needs of the land to be irrigated. The attempt to utilize such 

 excess rights can lead to nothing else than continued litigation and 

 trouble. The facts gathered in these investigations are already being 

 eagerly sought as a guide in the establishment of water titles, and 

 they are certain to prove one of the most effective agencies in pre- 

 venting erroneous or excess decrees in the future. 



A knowledge of the extent of the losses from canals is also nec- 

 essary to the proper distribution of the supply. Appropriations 

 usually contemplate the measurement of the volume allowed at the 

 head of the canal, hence the amount granted should be great enough 

 to meet all the necessities Of crops and also to allow for losses in transit. 

 If this estimated loss is too large the volume taken in at the head gate 

 will be greater than the needs of the land irrigated, but if too small 

 irrigators will suffer. Excessive allowance for these losses puts a 

 premium on poor construction, hence data is needed to show what are 

 reasonable losses and to prevent anything above this. Where losses 

 can be stopped appropriations should be cut down in order to compel 

 ditch owners to make them economical water carriers. Losses which 

 can not be stopped should be provided for. 



IRRIGATION LAWS. 



Along with the observations and experiments in the use of water 

 has gone a study of the laws and customs which control its distribu- 

 tion. This study reveals the fact that the development of irrigation 



