required for the Delta-Mendota Canal from existing Delta channels increased 

 in volume by greater discharges down Sacramento River, and to cut a channel 

 from Sacramento River to the center of the Delta to increase and improve the 

 water supply available at the Delta-Mendota intake. If insufficient water is 

 obtained by gravity through the initial channel, supplemental water will be 

 diverted through additional gravity channels or a low-lift pump system. 



The Sacramento-San Joaquin Delta is a. sea-level maze of channels, 

 low islands, and levees. It forms the uppermost extension of San 

 Francisco Bay and constitutes a common terminus for the two main river 

 systems in the Centrsl Valley. Approximately $00 miles of channels in 

 the Delta network mix the waters of Sacramento and San Joaquin Rivers 

 thoroughly; especially since the entire Delta system is influenced by 

 tidal action. Water in the Delta is generally fresh or only slightly 

 brackish, although seasonal and cyclic changes in salinity do occur. 

 Salinity is higher in late summer and fall, and lower in winter and 

 spring. In periods of drought, salinity increases in the Delta area suf- 

 ficiently to cause crop damage and to change the fauna inhabiting the 

 waters . 



The Sacramento-San Joaquin Delta is an especially important key in 

 the life history of anadromous fishes utilizing the streams of the Central 

 Valley as spawning areas. Adult and juvenile king salmon, striped bass, 

 shad, and two species of smelt pass through, spawn, or temporarily reside 

 in Delta waters. The Delta stream complex is also an extremely vital 

 nursery ground for the young of these species. Anything which threatens 

 to change the dynamics of Delta waters constitutes a potent threat to the 

 continued existence of these species which are valuable segments of the 

 well-developed fishery resources of the State of California and the Paci- 

 fic Coast in general. 



Salmon resources of California which are directly attrj bu table to 

 Central Valley and which will be endangered by the Central Valley Project 

 amount to an average annual commercial catch of 5, 600,000 pounds. This 

 average is derived from catch statistics covering the years 1916 through 

 19U6. It was calculated according to methods established by the Califor- 

 nia Division of Fish and Game from tagging experiments x\rhich fix propor- 

 tions of the troll catch attributable to the Central Valley Streams. It 

 also involves the total catch of the gill-net fishery in Sacramento and 

 San Joaquin Rivers. During the 30-year period the annual calculated catch 

 has ranged between 1,936,800 pounds in 1939 to 11,390,600 pounds in 19U6. 

 In addition to the commercial catch, there is a large sport fishery for 

 salmon both in the ocean and in the rivers. The total size of this fish- 

 ery is unknown. However, creel census studies show sport catches of about 

 62,uOO pounds in the 19u7-M3 season and 136,200 pounds in the 19U8-U9 

 season in the upper 100 miles of the Sacramento River alone. According to 

 the California Division of Fish and Game, approximately 20, COO salmon were 

 caught offshore on party boats during 19u8. Using the methods applied to 

 the commercial catches discussed above, we derive a figure of approxi- 

 mately ll^OOO fish which originated in the Central Valley. 



Opposite; Figure 1 - Map of Central Valley Project 



