19 



The distinctions between desert and arid regions were explained 

 and that under discussion was defined as being arid rather than 

 desert, for the most part, although the production of cultivated 

 crops without irrigation was impossible. The first settlement 

 established was a Moravian mission near the present western 

 boundary of Redlands. This was afterwards purchased by the 

 Mormons, who instituted local irrigation. The first extensive 

 irrigation operations were employed by the town of San Ber- 

 nardino, the present water supply of which is about 1,200,000 

 gallons, obtained by the deflection of Lytle Creek, besides a 

 large amount from deeply driven wells. This water supplies 

 not only the requirements of the city, but those of a large culti- 

 vated area. 



San Bernardino is near the western mouth of the large, some- 

 what horseshoe- shaped valley, from the mountains about which 

 all the water of the valley must come, except that which falls 

 during the rainy season, and which varies from six to twelve 

 inches in the different parts of the valley, the larger amounts fall- 

 ing successively nearer the mountains. The moisture brought 

 by the Pacific winds is precipitated in crossing these mountains 

 during the winter season only. At the greater elevations, 10,000 

 to 12,000 feet, it is deposited as snow; lower, in the form of 

 copious rains, and in the valley itself in a more or less scanty 

 rainfall. During this period, moisture is not carried to the great 

 interior plain of Nevada, Utah, Colorado, New Mexico, and 

 Arizona, where a dry season then prevails. In the summer, con- 

 ditions are exactly reversed, no rain whatever falling west of the 

 mountains. It thus happens that the San Bernardino valley gets 

 its natural water supply at a time when cultivation can derive the 

 least benefit from it and the problem is presented of preserving 

 the winter supply and distributing it during the summer. The 

 highly successful operations in the western part of the valley 

 demonstrated the existence of a most fertile soil of great depth, 

 and showed that the sole requirement for a rich agricultural region 

 was an abundant water supply. It was recognized that a town 

 located at the eastern end or top of the valley would be nearer 

 the mountain supply and that its subterranean streams would be 



