IRRIGATION INVESTIGATIONS 



Owin^ to the absence of the assistant engineer, Capt. A. L 

 Enger, and the difficulty in obtaining technical assistance, the work 

 of this department has been much restricted during the past year. 

 Certain features of Experiment Station work inseparable from the 

 office were performed as in previous years, while other features, 

 and especially research, suffered disproportionately. 



STATUwS OF IRRIGATION WATER SUPPLIES 



The year has been one of light rainfall and the necessity for 

 irrigation has increased. The stream flows have been meagre and 

 many areas have suffered for water. The advantage of water stor- 

 age has been exemplified in the Salt River Valley where plentiful 

 water has been available for an increased acreage, because of the 

 supply in Lake Roosevelt, stored during the flood years of 1915 and 

 1916. The lack of similar storage on the Gila River has been felt 

 keenly. The hundreds of thousands of acre-feet of water that were 

 wasted to the sea in 1915 and 1916 could have been used with great 

 advantage in 1917 and 1918 if a storage reservoir had been available. 

 Surely no other project in Arizona oflfers such inducement for gov- 

 ernmental action as the building of the San Carlos dam and irriga- 

 tion project. On the Colorado River, too, the time has arrived 

 when storage is necessary, for the natural flow during the period of 

 low discharge is entirely appropriated, and it will be necessary soon 

 for Arizona to join with other states in storage projects on the 

 Colorado, else even the right to flood waters of the river will be 

 lost. The Parker Valley, especially, should be provided with a 

 water supply at the earliest possible time. The need for action in 

 the development of storage projects has become more urgent by the 

 call for new lands on which returning soldiers can make homes. 

 Arizona is one of the states in which there is abundant opportunity 

 to prepare new lands under projects that are known to be economi- 

 cally feasible. 



AN IRRIGATION CODE 



Arizona, the most arid state, the one most in need of the modern 

 system of establishing and administering rights to water, is the only 

 irrigated state which has not adopted the system. The chaotic 

 condition of water rights in the Gila River watershed is retarding 

 the development of agriculture in southern Arizona and the lack of 



