130 THE MONTHLY BULLETIN. 



directly, either by gravity or mechanical means, from a surface stream. 

 Water rights may be obtained in existing canal companies and water 

 purchased at a stated price per acre or other unit of measure. Lands 

 may be irrigated from these canals by gravity flow or by means of 

 pumps. Wells may be sunk to reach the underground flow and pumps 

 nistalled to raise the water to the level of the land. 



When diverting directly from some surface stream the irrigator 

 should be certain that the minimum flow of the stream will be sufficient 

 for his needs during the irrigation season. He should know that his 

 rights to the necessary flow from the stream are assured and unques- 

 tionable and should investigate the means of diverting the w^ater to 

 convince himself that the proper amount of Avater may be delivered to 

 his property when recjuired. 



WJien purchasing water rights from an established company the 

 purchaser should investigate the resources of the company, its general 

 system, its water supply and the area to which it is or may be con- 

 tracting to deliver water. Evidence that the company can deliver 

 the required amount of water at the proper time should be demanded 

 by the intending purchaser. 



If wells are to be the means of supply for the irrigation of a rice 

 proposition a careful investigation of the underground water con- 

 ditions for that vicinity should be made and the irrigator should satisfy 

 himself that an ample flow may be expected at a reasonable depth. 



The quantity of w^ater required varies greatly under different con- 

 ditions. In the southern rice states it has been shown that a flow of 

 five gallons per minute is ample to care for one acre of rice. In an 

 irrigating season of five months this would amount to a little over 

 three acre feet. With an impervious subsoil at a depth of twenty to 

 thirty inches and the use of proper care in the preparation of the 

 ground and the application of the water, there is no reason why this 

 duty can not be made to apply to California conditions. Measure- 

 ments, however, show that, at present, double this amount of water is 

 being used in the rice fields of the state. 



As the irrigated area is increased and the available supply of water 

 for each acre is diminished it will become necessary for the irrigators 

 to use greater care in the design of their irrigation system and the 

 application of the water so as to increase as much as possilile the duty 

 of the water. 



While, in general, a gravity w^ater supply is preferable for rice 

 irrigation there are many arguments advanced by those favoring an 

 independent supply by means of pumps. Where the lift is low and 

 power accessible water may be pumped as cheaply or more cheaply 

 than it may be purchased from a number of the canal companies. It 

 is claimed l)y some that well water is too cold to properly mature the 

 crop and that the growing season is materially extended by its use. 

 Results seem to disprove this theory, as there are a number of cases in 

 this state where large yields in the average growing period have been 

 obtained on tracts irrigated by means of pumping from wells. In the 

 southern rice states large areas are irrigated by means of well water 

 and a number have installed pumps in preference tc receiving water 

 from canal companies. 



