148 



THE IRRIGATION AGE. 



Besides these uses, many of these lands are of ines- 

 timable value for mining purposes. These divisions 

 are, of course, only approximations, but they serve to 

 exhibit the proportional values of these great tracts. 

 Nearly three-fourths of the vacant public lands, or 22 

 per cent, of the whole United States, is adapted to 

 and is now quite fully utilized as a great free range 

 for cattle, and will continue to be so utilized until 

 disposed of by Congress or until the native grasses 

 and shrubs are destroyed by over-stocking the 

 ranges. Of that classified as wooded, a part is valu- 

 able for lumber, but the greater portion supports a 

 scanty growth of trees, suitable only for fire-wood 

 and fencing. Among the trees good grazing is 

 usually found, so that much of the wood land could 

 also be included under the head of grazing land. 



WATER SUPPLY IN RELATION TO ARID AND 

 SUB-HUMID LANDS. 



Any consideration of the quantity of vacant land 

 which can be utilized for other purposes than graz- 

 ing, wood land and mineral wealth must rest upon 



from creeks to large rivers, have been gauged, and a 

 record kept of their fluctuations from day to day 

 for periods of from one to five years, while a few 

 measurements have been made of a large number of 

 other streams. The results obtained have been 

 shown graphically upon the run-off map published in 

 the February number of THE AGE, and from this cer- 

 tain approximations have been obtained concerning 

 the total water supply of each of the States and Terri- 

 tories. In order to do this it is obvious that a num- 

 ber of assumptions must be made, both as regards 

 the actual quantity of water discharged and the pos- 

 sibility of utilizing this, and in such assumptions it is 

 doubtful whether any two men would arrive at iden- 

 tical conclusions. This fact, however, need not pre- 

 vent us from making the comparisons of water sup- 

 ply with land areas, for even if the results obtained 

 by other persons differ somewhat, the general conclu- 

 sion must be nearly the same, namely, that the water 

 supply is small as compared with the area of land. 



In order clearly to bring this out, the following 

 table has been prepared, showing for each of the 



ARIZONA 



CALIFORNIA 



COLORADO 



DAKOTAS 



IDAHO 



KANSAS 



MONTANA 



NEBRASKA 



NEVADA 



NEW MEXICO 



OREGON 



UTAH 



WASHINGTON 



WYOMING 



SHOWING THE TOTAL AREA OF ARID AND SUB-HUMID LANDS, THOSE IN PRIVATE OWNERSHIP AND THE 



AVAILABLE WATER SUPPLY FOR THE SAME. 



a consideration of the water supply of the area. 

 Estimates as to the possible water supply are based 

 upon accurate measurements of streams in different 

 parts of the arid region. It is obviously impractica- 

 ble, except by enormous expenditures, to ascertain 

 the quantities of water flowing in all the streams, and 

 therefore, in order to obtain definite data, such 

 streams have been measured as would give the best 

 results, not only for local use but for general conclu- 

 sions. From thirty to fifty streams, ranging in size 



States and Territories the total area of arid and sub- 

 humid lands, the area of arid and sub-humid lands in 

 private ownership, and the area of available water 

 supply: 



In estimating the water supply by States and Terri- 

 tories, two important assumptions have been made. 

 First, it has been assumed that the upper tributaries 

 of the Colorado river will ultimately be utilized in 

 such a manner as to take out all their water upon the 

 lands by the construction of canals and reservoirs, 



