DEPARTMENT OF CHEMISTRY, 



IRRIGATION WATERS. 



The examination of the water of the Salt, Gila and Colorado 

 rivers, the three principal sources for irrigation purpose: in the 

 Territory, has been completed during the year. The w rf is be- 

 ing tabulated and studied, and the results are to be published in 

 the near future. Some idea of the scope of the work may be 

 gained when it is understood tbat samples were taken daily for 

 one year, so far as possible, from the three above mentioned 

 rivers, and sent to the Station laboratories of the University, 

 where the examination to which they were subjected necessitated 

 the making of over two thousand analytical determinations. 



The year during which samples were taken proved to be in 

 some respects an unfortunate selection, owing to the fact that it 

 was abnormally dry, the rainfall in the watershed of the Salt 

 river being less than one-half of the average for the five or more 

 years for which the records have been kept. It therefore follows 

 that all the figures obtained are below what they would be for a 

 normal year. However, being a dry year, the amount of water 

 used by the canals more nearly approached the total volume of 

 the river ; hence, the flow of Salt river at all times being known, 

 the quantitative data for the effect of irrigation upon the lands of 

 the Salt river valley are available, because the various amounts 

 of silt and soluble salts carried upon the land very nearly ap- 

 proaches the total amount carried by the river. 



The quantitative silt determinations, both by weight and 

 volume, made upon these waters bear upon the discussions re- 

 lating to storage reservoir construction. Our observations, 

 though made during a year when the total silt was much smaller 

 than the average, are accurate, afford a reliable basis from 

 which to make estimations, and will yield a maximum figure for 

 tbe life of specified reservoirs upon the streams stated. 



The results will be of much value to the agriculturist, and to 

 prospective investors, not only showing the character of the irri- 



