106 



plant existence. In instances where no water was applied by 

 irrigation and the grass received only a low rainfall the yield 

 was equal to or greater than that produced when 21.5 inches of 

 irrigation was applied. 



Sugar grass .--Water received by sugar grass ( Carex aqua - 

 tilis ) grown in tanks varied from 17.80 inches to 40.92 inches. 

 Records of yield are incomplete, but those available show the 

 greatest yield for the most water received. 



Wire rush . — Use of water by wire rush in tanks varied from 

 9.58 inches of depth to 59.98 inches for peaty soil. Yield in 

 tons per acre is available only for three tanks which show the 

 largest yield for the most water received. 



MUD LAKE. IDAHO (29) 



Tules . — Additional data on consumptive use of water by 

 tules in a tank set in a swamp area are afforded by an investi- 

 gation of water resources of Mud Lake, Idaho, from 1921 to 1923, 

 inclusive. Results of the investigation indicate that 162,000 

 acre-feet of water appeared in Mud Lake and five smaller lakes 

 or reservoirs in the same vicinity during the year ending March 

 31, 1922. At that time three-fourths of the lake area and ad- 

 joining marshes were occupied by tule growth. 



Stearns and Bryan (29) state that "about 49,000 acre-feet 

 was used for the irrigation of about 13,300 acres, and about 

 108,000 acre-feet was discharged by evaporation and transpiration 

 from tules and other native plants of small economic value. The 

 data show that the natural losses were very large in proportion 

 to the quantity used for irrigation. They at once raise the ques- 

 tion whether the supply for irrigation can be increased by reduc- 

 ing the natural losses." 



As a means of measuring losses from swamp areas a tule pan 

 4 feet in diameter by 4 feet deep was set in the swamp. Tules of 

 about the same density as the surrounding growth were transplanted 

 into the pan. The soil was generally submerged to represent swamp 



