1902. 



FORESTRY AND IRRIGATION. 



159 



2,500,000 miner's inches, during the 

 month of June. The river gradually 

 decreases in volume through the late 

 summer and fall, reaching its lowest 

 stage, about 200,000 miner's inches, at 

 midwinter, during the cold weather 

 period of the high mountains. 



This water supply is particularly 

 adapted to the demands of irrigation, as 

 the period of greatest supply is coinci- 

 dent with that of greatest demand, and, 

 converseh', the low stages of the river 

 are during the season of the year when 

 plant life is least vigorous and the de- 

 mands of irrigation are not so great. 

 The river probably can furnish an 

 abundant supply of water to fully irri- 

 gate 3,000,000 acres of land, which is 

 probably a greater area than can ever 

 be commanded in the United States by 

 canals from this stream. 



The boat used on this expedition, 

 drawing eight inches of water, grounded 

 on sand bars on every da}' of the trip. 

 A stern-wheel iron steamer, drawing 

 12 inches of water, five days out from 

 the Needles, was passed 10 miles south 

 of the town. The river (January, 1902) 

 was unusually low and the conditions 

 unfavorable for navigation. However, 

 when high stages occur, the velocities of 

 the w^ater increase to six miles an hour, 

 and are difficult to overcome in going 

 upstream. Two steamers ply on the 

 river from Needles to the \^irgin River, 

 the Montezuma, and the Gila. Steamers 

 have been running on the river since 

 1852, and most of the heavy transporta- 

 tion to the mines is done b}^ them. They 

 would probably be abandoned as soon as 

 railroads entered into competition with 



them. The uses of the river for naviga- 

 tion would be small compared to the 

 benefits derived from its application for 

 irrigation. 



In conclusion, it may be stated: First, 

 that fully 500,000 acres of river bottom 

 lands between Needles and Yuma are 

 easily irrigable from the Colorado River; 

 second, that quite possibly extensive in- 

 terior diversions could be made for the 

 reclamation of larger areas of arid lands 

 near Yuma; third, that reservoir sites 

 exist at the Needles, above Bill Williams 

 Creek and above the Picacho dam site; 

 fourth, that reservoirs for impounding 

 flood waters for irrigation probably are 

 unnecessary on the stream; this to be 

 determined b}- further study of the water 

 supply and of the arsas of irrigable 

 lands ; fifth, owing to the low grade of 

 the stream and the high percentage of 

 silt carried by the water, di\-ersion weirs 

 probably will be necessary to raise the 

 water level at the head of the canal and 

 to act as settling basins therefor; sixth, 

 that the mining resources of the border- 

 ing mountain ranges are of such char- 

 acter as to justify the belief that a 

 general popu:ation and development of 

 the country will result in an extended 

 mining industry in this great interior 

 valley ; seventh , that the problem of the 

 most extensive and economic use of this 

 river is entirely too vast to be grasped, 

 either by a reconnaissance sur\^ey or 

 even by numerous independent line sur- 

 veys, and that the only possible or prac- 

 ticable way of solving the problem is by 

 the aid of a series of topographic maps 

 extending from the Mexican border up 

 to Ft. Mojave. 



FROST CHECKS AND WIND SHAKES. 

 By Eugene S. Bruce, 



Bureau of Forestrv. 



THE relation between frost checks 

 and so-called wind shakes in tim- 

 ber is not generally understood by man}^ 

 people who are greatly interested in both 

 trees and timber. My attention was first 

 called forcibly to this subject by noticing 

 the marked difference in sound between 



the clear and sharp crack of the trees 

 when frost was going into the timber, 

 after a spell of warm weather, and the 

 rather dull, muffled, and confined chug, 

 when the frost was leaving them, and 

 the temperature was rising rapidh'. 

 For a number of years it was neces- 



