CEA PE Er yar: 
IRRIGABLE LANDS OF THE SALT LAKE 
DRAINAGE SYSTEM. 
by G. K. GILBERT. 
The field of my work in 1877 included so large a portion of the 
drainage basin of Great Salt Lake and so little else that it has proved most 
convenient to report on all of that basin, or rather on that part of it which 
lies within the Territory of Utah. In so doing, I have depended, for nearly 
all the lands draining to Utah Lake, upon the data gathered by Mr. Ren- 
shawe, of this survey, in connection with his topographic work. The 
remainder of the district, with very slight exception, I have myself visited. 
The officials and citizens of the Territory have all freely contributed 
such information as I have sought, and have aided me in many ways; 
but I have been especially indebted to Mr. Martineau and Mr. Barton, the 
surveyors of Cache and Davis Counties; to Mr. Fox, the territorial sur- 
veyor; and to the Hon. A P. Rockwood, the statistician of the Deseret 
Agricultural Society. Mr. Rockwood prepared a statistical report on the 
Territory in 1875, which has been of great service to me, and he has 
kindly placed at my disposal the manuscript det ails of his work as well as 
the published summary. 
METHOD AND SCOPE OF INVESTIGATION. 
Where agriculture is dependent upon irrigation, the extent of land that 
can be put to agricultural use is determined by the relation of the quantity 
of available water to the quantity of available land. There is a certain 
amount of water needed by a unit of land, and wherever the land suscep- 
tible of cultivation requires more water than is obtainable, only a portion 
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