THE UNOCCUPIED LANDS OF COLORADO. 



supply of water found in this way is apparently in- 

 exhaustible and ordinary windmill pumping machin- 

 ery cannot pump them dry. 



CHARACTER OF THE SOIL. 



At some remote period the San Luis valley was 

 undoubtedly a great mountain lake, the mountain 

 ranges now bordering the valley forming its shores. 

 The soil which once formed the bottom of the lake 

 and now forms the valley lands is from ten feet in 

 depth in some places to hundreds of feet in others 

 and was made by sedimentary erosions carried down 

 from the surrounding mountain ranges. 



The soil in consequence contains mineral as well 

 as organic matter and is practically inexhaustible. 

 In many portions of the valley the soil contains a 

 mixture of volcanic ash which makes it admirably 

 adapted for the cultivation of small fruits. 



IRRIGATION IN THE VALLEY. 



The San Luis valley is admirably adapted tor irri- 

 gation. It is a smooth plain sloping from either side 

 to the center of the valley at an average grade of 

 about ten feet to the mile, and from the north to the 

 south at a lighter average slope, admitting of easy 

 irrigating. The character of the soil and the almost 

 absolute freedom from arroyos or breaks make ditch 

 building comparatively inexpensive so that perpetual 

 water rights in this valley cost the farmer 

 very little more than annual charges for 

 water in many sections of the country. 

 Although along the river bottoms many 

 farmers irrigate from individual ditches the 

 bulk of the land now under ditch is covered 

 by large ditch enterprises. 



Among the larger enterprises of this 

 character in the valley are the Rio Grande 

 Land and Canal Company which has over 

 100,000 acres under ditch. This company 

 has two canals taken from the Rio Grande 

 between the town of Monte Vista and Del 

 Norte aggregating seventy-five miles in 

 length with several hundred miles of laterals. 



Near Alamosa the Alamosa Land and 

 Canal Company has 100 miles of canals with 

 over 70,000 acres under ditch. The Empire 

 Canal Company also has a large canal sys- 

 tem under which is 70,000 acres. 



At Antonito in the southern part of the 

 valley the Toltec Canal Company has an 

 immen?e storage and canal system by which 

 the waters of the Conjos and San Antonio 

 rivers are impounded and 545,000,000 cubic 

 feet of water stored annually for purposes 

 of irrigation. 



SUB-IRRIGATION. 



N atural sub-irrigation is rapidly increas- 

 ing the acreage of farming land in the val- 



ley. Sub-irrigation is the process by which non- 

 irrigated lands lying between or contiguous to irri- 

 gated lands become productive and arable without 

 direct irrigation. A 40 acre tract without irrigation 

 if located between tracts of irrigated land, or if con- 

 tiguous to a large body of irrigated land for several 

 years, becomes productive and may be farmed profit- 

 ably without direct irrigation. The soil and sub-soil 

 of the San Luis valley are peculiarly adapted to sub- 

 irrigation and large areas are yearly being added to 

 the arable acreage by this method. 



INCREASING DUTY OF WATER. 



From the same conditions the duty of water is con- 

 stantly increasing and with each succeeding year the 

 farmer finds he needs less water for his land, or that 

 with the same-amount of water he can cultivate more 

 land. The increasing duty of water and the increas- 

 ing acreage by sub-irrigation are dispelling the idea 

 that large reservoir systems must be established 

 along the Rio Grande at the head of the valley in 

 order to increase the area of farm land in the valley. 

 It is probable that the immense acreage of the valley 

 will eventually be farmed and cultivated with no ad- 

 ditional water facilities, except the extension of canals 

 and laterals, than it now has in its canals, artesian 

 wells and surface wells. 



SAN LUIS VALLEY. 



