420 REPORT OF OFFICE OF EXPERIMENT STATIONS. 



limitation of the area which can be irrigated with the available water 

 supply. 



In man}' localities a lavish use of water has converted areas once 

 arid into alkali marshes, of which the only product is cat-tail flags, 

 and made drainage necessary at a cost fully as great as was required 

 to provide the water supply in the first instance. The need of this 

 drainage might have been avoided in many cases had canals been con- 

 structed with more care and the evil results of overirrigation appre- 

 ciated at the outset, 



The soils of the arid region are rich in mineral ingredients. This 

 is due in part to their origin and in part to the scanty rainfall, which 

 has not been sufficient to wash out the soluble elements, as has been 

 the case in humid regions. Because of this there are large areas which 

 are highly charged with alkali. The tendenc} T of irrigation is to leach 

 these salts out of the higher grounds and concentrate them in the 

 lower lands. Evaporation tends to bring them to the surface, where 

 they accumulate in such quantities as to kill vegetation. The remedy 

 is to be found in drainage, and this investigation has been called upon 

 to assist in solving the larger engineering and legal problems con- 

 nected with the formation of drainage plans. As some of these dis- 

 tricts embrace in the aggregate many thousands of acres, in which not 

 only the alkali but the water plane has risen until it has reached the 

 surface, it is necessary that the plans should be comprehensive, and 

 must include provision for removing the surplus water as well as the 

 salts which are to pass with it. Drainage studies must include the 

 causes of their being flooded and a determination of the source 

 and volume of the water to be removed. Drainage and irrigation 

 are a part of one whole, and their investigation should be carried 

 on together. The office is now engaged in this work in Colorado and 

 California. 



The publication and circulation of the facts being gathered regard- 

 ing the injuries resulting from excessive losses in distribution or 

 wasteful use will go far to prevent a recurrence of such injuries in 

 other localities where irrigation is yet in its infancy. Another result 

 will be the reclamation of more land than would otherwise be possible. 



INSTRUMENTS FOR MEASURING WATER. 



In carrying on the measurements of water it was found that the 

 instruments used were in many cases not suited to the work required 

 of them, and were so expensive as to limit their use generally to Gov- 

 ernment and State work. With the progress of the work of the 

 investigation there has been a growing demand for instruments which 

 will do accurate work and at the same time be within the reach of 

 canal companies and individual irrigators. The instruments most used 

 are the current meter and the register for keeping a continuous record 



