342 EEPORT UNITED STATES GEOLOGICAL SURVEY. 



The streams run full during the latter part of May and the most of June. 

 The rise takes place more or less suddenly, corresponding with the 

 rapidity of the melting of the snow in the mountains. After remaining 

 at flood height not more than a month, the streams begin to decrease 

 in volume, at first rapidly, then more gradually as the summer and fall 

 advance. The lowest stage of the water is in November and Decem- 

 ber. 



None of tlie streams of Colorado — and the same may be said of all 

 streams of the West except the Colorado and Columbia — carry sufficient 

 water to warrant the construction of large works in the form of reser- 

 voirs and irrigating canals. Several stupendous enterprises of this sort 

 have been projected in Colorado, but fortunately neither government 

 nor private capitalists have been induced to risk money in any such 

 schemes. 



The first of these in point of magnitude is proposed by Prof. Cyrus 

 Thomas, and incorrectly attributed to this Survey. The author describes 

 it as follows: " My plan is to throw up an embankment running north 

 and south from the Arkansas to the North Platte, curving east and west, 

 so as to follow a contour. Then, by throwing dams acioss the streams, 

 turn the water into this reservoir. * * * An embankment or wall, 

 averaging 30 to 40 feet in height, would, as the average slope here is 

 about 6 feet per mile, form a lake 6 to 8 miles wide and 200 miles long. 

 This would give a surface of some 1,200 square miles. * * * This 

 would irrigate from 12,000 to 14,000 square miles." He proposes to build 

 it on the east line of Colorado. This is truly a magnificent scheme, and 

 one worthy to be ranked with the Chinese wall and other expensive fol- 

 lies of which the world has been guilty. The difficulty would be to get 

 water for the reservoir. The total annual amount of water which the 

 three rivers, the Arkansas and the North and South Plattes, could pos- 

 sibly deliver at the reservoir, even were none of it used above for irri- 

 gation, would be 73,873,000,000 cubic feet, an amount sufficient to make 

 a depth of only about 2 feet in the reservoir. Now, as evaporation in 

 that climate is at the rate of 5 or 6 feet annually, and the greater part 

 of this in the summer, it can easily be seen that but a small part of the 

 "12,000 to 14,000 square miles" will have any chance of getting irri- 

 gated ; indeed, it would be difficult to keep the bottom of the reservoir 

 moist. 



Other plans are, in effect, to take the Arkansas and South Platte 

 from their beds at the foot of the cafion of each stream and carry them 

 over to the Arkansas divide bodily. The question, cui hoiio f is suf- 

 ficient answer to these schemes. There is far more than sufficient good 

 land in the immediate neighborhood of these streams to use up all the 

 water which they deliver annually. There is no necessity whatever for 

 carrying the water, in any case, more than 10 miles from the river. 

 Other things being equal, the water should be used near the mountains, 

 to avoid, as far as possible, loss by evaporation and sinL^ng. 



I should favor the plan of making a number of smaller reservoirs in 

 the bottom lands. There are many places on the Arkansas and South 

 Platte where, by the aijproach of the river bluffs to the stream on both 

 sides, a dam could be built to connect them, at slight expense, and thus 

 a considerable body of water imprisoned until needed. A succession 

 of these along the streams, placed where the local topography and the 

 ' needs of the land require, would serve the purpose of utilizing all the 

 water which is annually sent down from the mountains. 



As a favorable place to build a large reservoir, in which all the water 

 of the Arkansas might be stored, I will mention a small valley in the midst 



