

14 



THE AURIFEROUS GRAVELS OF THE SIERRA NEVADA. 



the farmer to secure a bountiful harvest. In the winters from 1870 to 1873 

 the annual rain-fall at Visalia was as follows: for the year 1870-71 6.8 

 inches; 1871-72, 10.3 inches; 1872-73, 7.2 inches. The crops of the 

 year 1872 were abundant, those of the other years mentioned were failures. 

 That the Great Valley on the whole is a dry region, is abundantly proved 

 by the scantiness of its population. But there are here all possible facilities 

 for artificial irrigation, with the aid of the copious streams coming down the 

 slopes of the Sierra ; although to utilize these in a suitable and economical 

 Avay demands considerable capital and engineering skill, combined with in- 

 telligent action on the part of the Legislature, backed up by the good will 

 of a law-abiding people. 



The enumeration of the streams draining the western slope of the Sierra, 

 as given in the preceding pages, indicates very clearly a considerable amount 

 of precipitation in that region. Unfortunately there are no statistics giving 

 the amount of rain and snow-fall for any considerable period at a sufficient 

 number of stations to enable us to form any idea of the general average ; 

 neither are there any measurements of the amount of water carried down in 

 the different streams, which amount is not only very variable from month to 

 month during the year, but also from year to year. That the precipitation 

 is almost entirely during the winter months has been already stated ; that it 

 increases with the elevation would also be inferred j and, the southern por- 

 tion of the Sierra being higher than the northern, it is probable that this 

 increased elevation about compensates for the difference in latitude. If the 

 Sierra opposite the Tulare Valley were no higher than it is from Sacramento 

 north, we should almost certainly have no such large streams flowing down 

 in that region as the Kern and King's. If, moreover, the rain-fall were 

 equally distributed throughout the year, instead of being, as it now is, limited 

 to less than six months, the condition of things would be greatly changed, 

 especially in relation to the mining interests of the Sierra. Almost the whole 

 precipitation in the higher portions of the range is in the form of snow ; and 

 this usually remains in large part upon the surface, gradually melting away 

 during the early spring and summer months, so that it forms a much 

 more reliable source of supply than it would do if it had fallen chiefly as 



The system of dams, reservoirs, and ditches by which the water of 

 the High Sierra in the mining region is made available for the purposes of 

 the miner, is very extensive, and a large amount of capital is invested in this 

 form of improvements. The total quantity of the precipitated moisture in the 



ram. 





