overflow; therefore, the profiles are relatively salt-free 

 and somewhat stratified. Parent materials consist of mixed 

 rock sources. 



The Sacramento series, which is located north of Tracy, is 

 also characterized by frequent overflow. These soils 

 usually have a high organic matter content. Very little 

 acreage has been subjected to tile drainage. 



The Hacienda series is represented by a small acreage in the 

 Tulstre Lake area. These soils are more stratified and more 

 strongly developed than are those in the Tulare series. 



Climate 



Climate greatly affects the quantity and quality of tile 

 drainage along the west side. Heavy rainfall causes leaching 

 of surface soil and, when excessive, may cause increases in 

 tile flow and changes in quality. Too little rain and high 

 temperatures result in increased irrigation, which directly 

 Influence tile discharge and its quality. 



Temperature 



The climate along the west side of the San Joaquin Valley is 

 typically arid, with maximum daytime temperatures frequently 

 exceeding 100°F in July and August. Average annual tempera- 

 tures vary only slightly from one climate station to another; 

 differences between years are also small, as shown in Table 3, 



TABLE 3 



AVERAGE ANNUAL TEMPERATURE 



AT SELECTED WEATHER STATIONS i/ 



ALONG THE WEST SIDE 



Location 1^39 IS/60 I96I 1966 I963 I96U 196^ 1966 196? I968 IQfr' 



Tracy Carbona 62.0 6I.6 6l.2 59.7 59-5 60.7 60.I 61.7 61.3 61. 2 61.1. 



Weetley UK 6U.3 &*.o 61.7 60.5 61.0 63. 62. U 59.2 61.I 62.8 



Nevman 6I.I* 6l.2 6I.O 60.I 59-7 6o.2 60.3 6I.5 60.7 6D.9 60.5 



Los Bancs 63.5 62.U 62.2 61.3 60.7 60.7 61. 6 62.7 62.1 62.8 61.1. 



Corcoran NF 63.3 62.4 61.8 6l.2 61.8 61.8 63.3 62.6 62.8 6e.l 



1/ U. S. weather Bureau, Department of Water Resources, and cooperative stations. 

 NF = No record. 



26 



