THE lEEIGATIOiNT AGE. 



937 



Grande is compelled to flow across the line from Colorado 

 into New Mexico, it will destroy from 1,000,000 to 1,500,000 

 acres of agriculture above in order to save 200,000 or 300,000 

 acres in the valley below. 



Major Powell urged that the tributaries of the Rio 

 Grande below the Colorado-New Mexico line would, if the 

 water were conserved, furnish a sufficient flow to maintain 

 the irrigation of that section as then developed. He pointed 

 out that "when the river emerges into the valley at the foot 

 of Embudo Canyon it is a fine stream and must always be so 

 whatever water is taken out in Colorado above," That this 

 somewhat startling and paradoxical statement is borne out 

 by the facts is indicated in the following paragraphs, where 

 the explanation is suggested. 



The great excess of water wasted during the flood sea- 

 son and the frequent lack of water when needed have turned 

 attention to the possibility of reservoirs in the upper course 

 of the streams to conserve the flood water and have led to 

 search for available sites. Naturally those first sought are 

 the ones requiring the least expenditure of money to make 

 them available. The head branches of most of the larger 

 streams emptying into the valley held glaciers of various 

 size during past ages, and many of the morainic dams and 

 terraces resulting from glacial action offer tempting sites for 

 storage reservoirs. Such formations require most careful 

 testing, because from the nature of their material they will 

 not, as a general rule, hold water after it has accumulated 

 in volume sufficient to cause much pressure. But doubtless 

 there are numerous sites in the various streams that will serve 

 admirably. Such are reported on Alamosa Creek and in the 

 upper course of the Rio Grande. One of those on the Rio 

 Grande has been thoroughly tested by the company operating 

 the Rio Grande and Monte Vista canals, and a reservoir is 

 now under construction. 



FIGURE 1. Outline map of Colorado. showing location of San Luis Valley. 



The high gradient and the small drainage areas of the 

 streams coming down from the Sangre de Cristo Range 

 preclude the establishment there of any but small irrigation 

 systems. On the other hand, the low gradient and large 

 drainage areas of the streams entering from the west side of 

 the valley are very advantageous to large systems. Toward 

 their headwaters these streams branch out and their valleys 

 take _ on the rolling character of glaciated cirques and are 

 heavily covered with pine and spruce. The timber, by check- 

 ing the run-off in time of heavy rains and by protecting the 

 snow from rapid melting, controls the discharge of the 

 streams and to that extent does away with the necessity for 

 storage reservoirs. 



IRRIGATION. 



Canals. The full flows of all the streams entering the 

 valley are appropriated for purposes of irrigation. The Rio 

 Grande is the main source of supply. The following table 

 shows the total appropriations and dates of the main priori- 

 ties of the principal canals and ditches taking water from that 

 streams, as decreed by the courts in 1900: 



Water appropriated for principal ditches and canals from the 



Rio Grande, and total decreed appropriation. 

 Priority. Canal. Appropriation. 



Cubic feet. 



Centennial ditch 82.4 



Rio Grande (Del Norte) canal 905.6 



Monte Vista (Citizens') canal 257.8 



1883 and 1890 Empire canal 667.5 



1885 San Luis Valley Canal 92.9 



1886 Costilla ditch 103.3 



1887 Prairie Ditch 105.1 



1887 Farmers' Union canal. . 138.8 



1874 and 1879 



1881 and 1891 



1882 and 1889 



Total of principal ditches and canals 2,353.4 



Total appropriation decreed by court to 1900 . . 3,022.59 



The foregoing table, when compared with the table giv- 

 ing the average monthly flow of the Rio Grande from April 

 to September, inclusive, for sixteen years shows that the 

 waters of this stream are greatly overappropriated, even in 

 the flood season. 



Average monthly discharge of the Rio Grande at Del Norte, 

 1890-1905. 



Second-feet. 



April 968 



May 2,505 



June 2,605 



July 864 



August 474 



September 404 



Acres irrigated from the Rio Grande and tributaries. 



Percent. 

 County. 1899. 1889. increase. 



Hinsdale 1,339 1,389 



Mineral 2,640 



Saguache 75,909 52,453 44.7 



Rio Grande 71,325 21,797 227.2 



Costilla 50,290 25,918 94.0 



Conejos 98,486 46,273 112.8 



299,989 147,830 102.9 



This acreage is confined to the San Luis Valley, except 

 perhaps 10,000 acres lying on the upper courses of the river 

 or its tributaries. 



Between Mosca and Hooper is a region in which the sup- 

 ply of ditch water for several years has been inadequate, and 

 here was developed the scheme of installing a gasoline pump- 

 ing plant and pumping from the underground water level 

 as raised and maintained by subirrigation. No change in the 

 application of the water thus gained was proposed. It was 

 to be used in subirrigating ; that is, the level of underground 

 water was to be raised by adding to it water taken from it 

 another statement of the problem of raising one's self by 

 one's foot straps. The application of the water might be 

 changed by the substitution of surface irrigation for subirri- 

 gation methods, thus doing away with the necessity of keeping 

 up the underground water level; but a difficulty appears in 

 that case. The interesting question is raised as to the right 

 djt one person to lower the water level when his neighbors, 

 in the customary practice of irrigation, are under the necessity 

 of keeping it up. 



Many of the smaller streams on either side of the valley 

 run out into the valley during the flood season but during 

 the remainder of the year, except for short intervals, disap- 

 pear beneath the gravel, where they emerge from the moun- 

 tains at the upper edge of the alluvial slope. But by digging 

 down a few feet in the rocky channels of such streams a 

 persistent and heavy underflow is encountered. It is possible 

 by installing a gasoline pumping outfit to raise this underflow 

 and irrigate successfully when the water is not running in the 

 streams. One such pumping outfit has been in successful 

 operation in 1903 and 1904 by Mr. K. Eilinghoff 2 miles east 

 of Chamberlain Hot Springs. The equipment consisted of a 

 3^-horsepower gasoline engine and a 2-inch centrifugal pump 

 with a normal discharge of 125 gallons per minute. The 

 water was taken from a well 16 feet deep, in which the water 

 stood within 7 feet of the surface but with steady pumping 

 sank to 11 feet from the surface, where it remained. 



The cost of installing such an outfit is not large, and the 

 cost of operating for the short time it would ordinarily be in 

 use, at critical periods in the growth of the crop, will also 



