68 



DIVISION OF WATER RESOURCES 



experiments were conducted and are not applicable to other localities 

 with markedly different climatic conditions. 



SOIL CHARACTERISTICS 



The top soil at the Santa Ana station was overlying a coarse water 

 bearing sand at a depth of 6 to 7 feet. It contained considerable mica 

 and some alkali in qnantities not detrimental to the varieties of vege- 

 tation nsed in the investigation. A thin layer of finer than average 

 material lay at a depth of about 4 feet in all Santa Ana tanks, a 

 mechanical analysis of which showed that 29 per cent should be classed 

 as very fine sand and 59 per cent as silt. This fine material was unim- 

 portant, as in all tests except one it lay below the water table and 

 could have no effect on capillary rise of moisture or rate of transpira- 

 tion. In the one case referred to, where it was a few inches above 

 the water table, it apparently had no influence on rate of movement 

 of soil moisture. Soil at the San Bernardino station is classed as Chino 

 silt loam and is relatively free from alkali. 



Mechanical Analyses 



Mechanical analyses of soil from five tanks at the Santa Ana 

 station and from two tanks at the San Bernardino station were made, 

 and the percentages of different sized soil particles are shown in Table 

 23. Each sample of soil, representing 1 foot in depth and weighing 



TABLE 23 



MECHANICAL ANALYSES OF SOIL FROM TANKS AT SANTA ANA AND 

 SAN BERNARDINO STATIONS 



Tank 

 number 



Depth of 

 sample, 

 in feet 



Per cent of material retained on screens of the following s'zes 



No. 14 



No. 28 



No. 48 



No. 100 



No. 200 



Per cent 



of material 



passing 



screen 



No. 200 



