68 (Beograpbfcal IRotes on 



It receives the drainage of all the eastern slopes of the Durango 

 sierras and the western slopes of the Coahuila ranges, but possesses no 

 outlet. As a consequence, throughout its whole area, the rivers run 

 into broad, shallow lakes, whence the waters are gradually lost by 

 evaporation during the dry season. Of these rivers, the largest is the 

 Nazas, which has a course of nearly three hundred miles from its 

 source to where it is dispersed over the shallows, called on modern 

 maps Lake Mayran. Sixty or seventy years ago the Nazas discharged 

 its waters into a series of extensive lagoons, occupying what is now 

 the fertile Laguna district of Durango and Coahuila. 



At that time a phenomenal and long-continued rainfall so over- 

 charged the, then, bed of the Nazas as to cause it to open a new 

 course, and leave the Cayman lagoons thirty miles on one side. In 

 the course of years these lagoons were converted into a mesquite wil- 

 derness, almost dead level, and composed of a deposit of the finest 

 detritus, of unknown depth. The central depression of this lake-bed 

 filled a broad valley running north and south, and surrounded by a 

 parallelogram of mountains. The area thus comprised was about two 

 hundred and ten square miles of pure vegetable loam, locally known as the 

 Lake of Tlahualilo. This cuenca, or bowl, was the spot chosen about 

 six years ago for the establishment of the great irrigation enterprise. 



The problems involved called for courage and high administrative 

 qualities, as well as technical engineering knowledge. It had early 

 developed that the lands left dry by the changed course of the river 

 were of extraordinary fertility, and half a century ago these tracts, 

 immediately adjacent to the river, had been taken up and brought 

 under irrigation after the rough methods then practised. The result 

 was that, by 1890, about 250,000 acres of this land were under ditch, 

 and the region was producing the greatest part of the cotton grown in 

 Mexico, as well as heavy crops of corn and wheat. The Tlahualilo 

 basin was known to be the richest portion of this district, but the 

 thirty miles of sun-baked desert separating it from the present course 

 of the river presented an obstacle to utilization which proved too 

 formidable for the cultivators of the Laguna country. In 1889 a 

 project was formulated for carrying a ditch across the intervening 

 desert to the head of the Tlahualilo cuenca, and converting the 

 whole of the latter area into a huge hacienda. 



Preliminary survey showed that the lowest level of the basin to be 

 irrigated was about 100 feet below the point on the river Nazas 

 which it was proposed to dam ; that the main canal, on account of 

 topographical conditions, would require a development of 39 miles ; 

 and that the slope of the lands within the basin was such that about 

 175 square miles out of the 210 composing the basin could be advan- 

 tageously irrigated. A company was formed to undertake the work. 



